Include what the new code uses

The Windows build stopped on test_kdtree.cpp: it calls std::iota without
including <numeric>, which libstdc++ happens to pull in anyway. Added
there, and the same for <limits> and <algorithm>/<cmath> where the
recent changes rely on them being included by something else.

docs/HLSD/preset-cache.md

@@ -28,8 +28,8 @@ Per-vendor granularity is what makes the system practical:
 - A vendor whose profile is bumped invalidates only its own cache. The other 60-odd
   vendors keep theirs — even when the bumped vendor is the shared Orca filament
   library everyone else inherits from.
-- The setup wizard loads its vendors through the same routine as startup, so it
-  gets the same speedup without a second code path.
+- The setup wizard, which loads vendors one at a time, gets the same speedup as
+  startup without a second code path.
 - A vendor with no cache, or a broken one, costs only that vendor a parse.
 
 A cache holds *system* presets only. User presets, project settings and modified
@@ -162,20 +162,15 @@ cache nothing can invalidate is worse than no cache.
 
 Vendors load in a fixed order, because filament inheritance crosses exactly one
 boundary: any vendor's filament may inherit from the shared Orca filament library,
-and nothing else reaches across vendors — an `include` is always vendor-local. Only
-installing a vendor's presets crosses it; reading the vendor, from its cache or its
-JSONs, needs nothing from the library. So every other vendor is read while the library
-loads, each is installed against it as soon as both are done, and the results are
-merged in a stable order:
+and nothing else reaches across vendors — an `include` is always vendor-local. The
+library therefore goes first, alone; every other vendor follows in parallel, resolving
+against it; and the results are merged in a stable order:
 
 ```mermaid
 flowchart LR
-    lib["1 · OrcaFilamentLibrary loaded;<br/>meanwhile every other vendor read<br/>from its cache or its JSONs"] --> par["2 · every other vendor installed<br/>in parallel, each into its own bundle,<br/>filaments resolving against the library"] --> merge["3 · bundles merged into one,<br/>in one pass per collection,<br/>in stable vendor order"]
+    lib["1 · OrcaFilamentLibrary<br/>loaded first, synchronously"] --> par["2 · every other vendor in parallel,<br/>each into its own bundle, filaments<br/>resolving against the loaded library"] --> merge["3 · bundles merged into one,<br/>sequentially, in stable vendor order"]
 ```
 
-`PresetBundle::load_vendors` runs these steps for startup and for the setup wizard,
-which hand it the vendors to load and the directory each is installed in.
-
 Whether a vendor comes from its cache or from a parse changes nothing in that
 order — both produce the same bundle, so cached and parsed vendors mix freely in
 one startup.
@@ -216,12 +211,11 @@ shipped cache answered first, so the profile in `<data_dir>/system/` was never p
 and its cache was never written back.
 
 Serving from a cache is not a memory-image restore. The entries are deserialized and
-then installed by `install_vendor`, the routine the JSON path hands the vendor's entries
-to once it has parsed the sub-files: inheritance resolved against the presets installed
-before them and the currently loaded filament library, includes layered in, configs
-flattened onto the collection defaults, validated and registered. An `include` layers
-what the included base states, between the parent and the preset's own keys: the base's
-diff against the
+then installed one by one — inheritance resolved against the presets installed before
+them and the currently loaded filament library, includes layered in, configs flattened
+onto the collection defaults, validated and registered — by the same function the JSON
+path calls straight after parsing a sub-file. An `include` layers what the included
+base states, between the parent and the preset's own keys: the base's diff against the
 default, taken when the base itself was installed and before the per-variant padding
 `inherits` sees, so only what a template sets reaches the presets including it. The two
 paths share everything below the parse, which is what makes a cache-loaded bundle
@@ -229,16 +223,6 @@ indistinguishable from a JSON-loaded one by construction rather than by test cov
 Installation also rebuilds each preset's file path from the local data directory, so a
 shipped cache never carries the generating machine's paths.
 
-Installing an entry is split in two. `resolve_vendor_preset` flattens it, reading only
-what is registered under the names it inherits and includes, and `commit_vendor_preset`
-registers it, the only step that writes anything shared. Entries resolve across threads
-in runs and commit in the order the vendor lists them. A run ends before an entry that
-inherits or includes one already in it, since that one's commit registers what the
-entry resolves against, so no entry in a run reads what another in it registers. An
-entry's parse messages are held until it commits. The bundle, the log's parse and
-install messages and the error count therefore come out as parsing and installing one
-entry at a time would leave them, whatever the listing order.
-
 App upgrades work because a cache normally survives one. Only a deliberate
 `CACHE_VERSION` bump makes an installed cache unreadable, and that is handled at
 install time rather than at load: a vendor whose cache this build cannot read counts
@@ -270,20 +254,17 @@ the wizard caches the *derived JSON*, not another form of the inputs:
 open, the wizard computes the current stamps (one version peek per vendor) and, when
 they match, serves the catalog from the file — no bundle built, no preset installed.
 Caching bundle inputs instead was tried and measured: rebuilding the bundle from
-per-vendor caches costs over a second of preset installation whatever feeds it, so
-only skipping the rebuild entirely wins.
+per-vendor caches costs ~2 s of preset installation whatever feeds it, so only
+skipping the rebuild entirely wins.
 
 Any change to the set — a vendor added, removed or updated, or its cache-only
 `.opc` replaced by a newer one — changes the stamps and retires the whole file;
-the wizard then rebuilds the bundle with `PresetBundle::load_vendors`, the load
-startup uses (per-vendor caches serving where they cover), and writes the catalog
-back. When a vendor fails to load, the filament library included, that open falls
-back to the wizard's own scan of the vendor JSONs, as when no bundle can be built,
-and writes nothing. Selections, region and per-open decorations are applied
-downstream of the cache either way, so a served catalog is indistinguishable from a
-rebuilt one. Nothing ships this file and the updater never touches it; it is a
-locally written artifact, re-derived whenever stale, written through a temp file and
-rename so half a cache is never readable.
+the wizard then rebuilds the bundle vendor by vendor (per-vendor caches serving where
+they cover) and writes the catalog back. Selections, region and per-open decorations
+are applied downstream of the cache either way, so a served catalog is
+indistinguishable from a rebuilt one. Nothing ships this file and the updater never
+touches it; it is a locally written artifact, re-derived whenever stale, written
+through a temp file and rename so half a cache is never readable.
 
 The cache lives under `<data_dir>/cache/`, not beside the vendors: everything that
 scans `<data_dir>/system/` treats any `.opc` there as a vendor, so a non-vendor
@@ -397,13 +378,6 @@ enumerates only `*.json` will find no vendors at all in a packaged build.
   the `CachedPreset` field list — written and read by `visit_entry` in
   `PresetCacheFormat.cpp`, one list for the save, the load and the name peek alike — or
   the cache's own layout or stamps, requires bumping `CACHE_VERSION` by hand.
-- **Adding a kind of reference between presets**, as `inherits` and `include` are:
-  parse the names into `CachedPreset` (a field change, so `CACHE_VERSION` is bumped),
-  have `install_vendor_entries` end a run before an entry that names one already in it
-  and retain what the names point at, look them up only in `resolve_vendor_preset`, and
-  register what they point at only in `commit_vendor_preset`. The listing-order test in
-  `test_vendor_cache.cpp` fails for a kind the runs do not check once its fixture uses
-  it.
 - **The dictionary indexes with a `uint16`**, so `print_config_def` may hold at most
   65535 options and one cache at most 65535 distinct enum value names.
   `CacheDictionary::save` throws past that, which surfaces when CI generates the

src/libslic3r/AppConfig.cpp

@@ -5,7 +5,6 @@
 //BBS
 #include "Preset.hpp"
 #include "Exception.hpp"
-#include "InstanceLock.hpp"
 #include "LocalesUtils.hpp"
 #include "Thread.hpp"
 #include "format.hpp"
@@ -740,13 +739,10 @@ static bool verify_config_file_checksum(boost::nowide::ifstream &ifs)
 
 
 #ifdef USE_JSON_CONFIG
-std::string AppConfig::load(bool read_only)
+std::string AppConfig::load()
 {
     json j;
 
-    // Keep another instance from replacing or restoring the file mid-read.
-    InstanceLock instance_lock(read_only ? std::string() : lock_path());
-
     // 1) Read the complete config file into a boost::property_tree.
     namespace pt = boost::property_tree;
     pt::ptree tree;
@@ -996,6 +992,7 @@ void AppConfig::save()
     // The config is first written to a file with a PID suffix and then moved
     // to avoid race conditions with multiple instances of Slic3r
     const auto path = config_path();
+    std::string path_pid = (boost::format("%1%.%2%") % path % get_current_pid()).str();
 
     json j;
 
@@ -1125,18 +1122,43 @@ void AppConfig::save()
 
         j["local_machines"][local_machine.first] = m_json;
     }
-    const std::string config_str = j.dump(1, '\t');
-    if (write_config_file(path, config_str + "\n", config_str))
-        m_dirty = false;
+    boost::nowide::ofstream c;
+    c.open(path_pid, std::ios::out | std::ios::trunc);
+    c << j.dump(1, '\t') << std::endl;
+
+#ifdef WIN32
+    // WIN32 specific: The final "rename_file()" call is not safe in case of an application crash, there is no atomic "rename file" API
+    // provided by Windows (sic!). Therefore we save a MD5 checksum to be able to verify file corruption. In addition,
+    // we save the config file into a backup first before moving it to the final destination.
+    c << appconfig_md5_hash_line(j.dump(1, '\t'));
+#endif
+
+    c.close();
+    if (c.fail()) {
+      BOOST_LOG_TRIVIAL(error) << "Failed to write new configuration to " << path_pid << "; aborting attempt to overwrite original configuration";
+      return;
+    }
+
+#ifdef WIN32
+    // Make a backup of the configuration file before copying it to the final destination.
+    std::string error_message;
+    std::string backup_path = (boost::format("%1%.bak") % path).str();
+    // Copy configuration file with PID suffix into the configuration file with "bak" suffix.
+    if (copy_file(path_pid, backup_path, error_message, false) != SUCCESS)
+        BOOST_LOG_TRIVIAL(error) << "Copying from " << path_pid << " to " << backup_path << " failed. Failed to create a backup configuration.";
+#endif
+
+    // Rename the config atomically.
+    // On Windows, the rename is likely NOT atomic, thus it may fail if PrusaSlicer crashes on another thread in the meanwhile.
+    // To cope with that, we already made a backup of the config on Windows.
+    rename_file(path_pid, path);
+    m_dirty = false;
 }
 
 #else
 
-std::string AppConfig::load(bool read_only)
+std::string AppConfig::load()
 {
-    // Keep another instance from replacing or restoring the file mid-read.
-    InstanceLock instance_lock(read_only ? std::string() : lock_path());
-
     // 1) Read the complete config file into a boost::property_tree.
     namespace pt = boost::property_tree;
     pt::ptree tree;
@@ -1274,6 +1296,7 @@ void AppConfig::save()
     // The config is first written to a file with a PID suffix and then moved
     // to avoid race conditions with multiple instances of Slic3r
     const auto path = config_path();
+    std::string path_pid = (boost::format("%1%.%2%") % path % get_current_pid()).str();
 
     std::stringstream config_ss;
     if (m_mode == EAppMode::Editor)
@@ -1309,38 +1332,38 @@ void AppConfig::save()
     // One empty line before the MD5 sum.
     config_ss << std::endl;
 
-    const std::string config_str = config_ss.str();
-    if (write_config_file(path, config_str, config_str))
-        m_dirty = false;
-}
-#endif
-
-bool AppConfig::write_config_file(const std::string &path, std::string body, const std::string &checksum_source)
-{
-    // Everything before this is assembly; only the writes need the other instances kept out.
-    InstanceLock instance_lock(lock_path());
+    std::string config_str = config_ss.str();
+    boost::nowide::ofstream c;
+    c.open(path_pid, std::ios::out | std::ios::trunc);
+    c << config_str;
 #ifdef WIN32
-    // WIN32 specific: the final replace is not safe in case of an application crash, there is no atomic "rename file" API
+    // WIN32 specific: The final "rename_file()" call is not safe in case of an application crash, there is no atomic "rename file" API
     // provided by Windows (sic!). Therefore we save a MD5 checksum to be able to verify file corruption. In addition,
     // we save the config file into a backup first before moving it to the final destination.
-    body += appconfig_md5_hash_line(checksum_source);
+    c << appconfig_md5_hash_line(config_str);
 #endif
-    // Not flushed to the device: the idle handler saves on the GUI thread after
-    // any change, and the rename already gives a complete old or new file.
-    if (const std::error_code ec = write_file_atomically(path, body)) {
-        BOOST_LOG_TRIVIAL(error) << "Failed to write the configuration " << path << ": " << ec.message() << "; trying again in 10 s";
-        m_retry_save_at = std::chrono::steady_clock::now() + std::chrono::seconds(10);
-        return false;
+    c.close();
+    if (c.fail()) {
+      BOOST_LOG_TRIVIAL(error) << "Failed to write new configuration to " << path_pid << "; aborting attempt to overwrite original configuration";
+      return;
     }
-    m_retry_save_at = {};
+
 #ifdef WIN32
-    // Written after the config, so the backup never holds a state that was not confirmed written.
-    const std::string backup_path = (boost::format("%1%.bak") % path).str();
-    if (const std::error_code ec = write_file_atomically(backup_path, body))
-        BOOST_LOG_TRIVIAL(error) << "Failed to write the backup configuration " << backup_path << ": " << ec.message();
+    // Make a backup of the configuration file before copying it to the final destination.
+    std::string error_message;
+    std::string backup_path = (boost::format("%1%.bak") % path).str();
+    // Copy configuration file with PID suffix into the configuration file with "bak" suffix.
+    if (copy_file(path_pid, backup_path, error_message, false) != SUCCESS)
+        BOOST_LOG_TRIVIAL(error) << "Copying from " << path_pid << " to " << backup_path << " failed. Failed to create a backup configuration.";
 #endif
-    return true;
+
+    // Rename the config atomically.
+    // On Windows, the rename is likely NOT atomic, thus it may fail if PrusaSlicer crashes on another thread in the meanwhile.
+    // To cope with that, we already made a backup of the config on Windows.
+    rename_file(path_pid, path);
+    m_dirty = false;
 }
+#endif
 
 bool AppConfig::get_variant(const std::string &vendor, const std::string &model, const std::string &variant) const
 {
@@ -1830,11 +1853,6 @@ void AppConfig::reset_selections()
     }
 }
 
-std::string AppConfig::lock_path()
-{
-    return Slic3r::data_dir().empty() ? std::string() : config_path() + ".lock";
-}
-
 std::string AppConfig::config_path()
 {
 #ifdef USE_JSON_CONFIG
@@ -1871,7 +1889,7 @@ bool AppConfig::exists()
 
 std::string AppConfig::load_if_exists()
 {
-    return boost::filesystem::exists(loading_path()) ? load(/*read_only=*/true) : std::string();
+    return boost::filesystem::exists(loading_path()) ? load() : std::string();
 }
 
 }; // namespace Slic3r

src/libslic3r/AppConfig.hpp

@@ -2,7 +2,6 @@
 #define slic3r_AppConfig_hpp_
 
 #include <set>
-#include <chrono>
 #include <map>
 #include <string>
 #include "nlohmann/json.hpp"
@@ -123,18 +122,14 @@ public:
 
 	// Load the slic3r.ini from a user profile directory (or a datadir, if configured).
 	// Return an error string, or an empty string on success.
-	std::string         load(bool read_only = false);
+	std::string         load();
 	// Treat a missing config as default state; otherwise load it normally.
-	// The CLI's load: it never saves, so it takes no lock and creates no lock file.
 	std::string         load_if_exists();
 	// Store the slic3r.ini into a user profile directory (or a datadir, if configured).
 	void 			   	save();
 
 	// Does this config need to be saved?
 	bool 				dirty() const { return m_dirty; }
-	// False for ten seconds after a failed write, so the idle handler does not
-	// repeat a hopeless attempt on every event; an explicit save() always tries.
-	bool 				save_due() const { return std::chrono::steady_clock::now() >= m_retry_save_at; }
 
 
 	void				set_dirty() { m_dirty = true; }
@@ -344,8 +339,6 @@ public:
 
 	// Get the default config path from Slic3r::data_dir().
 	std::string			config_path();
-	// Lock file guarding config_path() against other running instances; empty without a data dir.
-	std::string			lock_path();
 
 	// Returns true if the user's data directory comes from before Slic3r 1.40.0 (no updating)
 	bool 				legacy_datadir() const { return m_legacy_datadir; }
@@ -456,16 +449,8 @@ private:
 
 	// Preset for each machine
 	MachineSettingMap											m_printer_settings;
-	// Writes the assembled config text, and on Windows its checksum and a backup copy; false when the
-	// config itself could not be written, in which case the caller stays dirty and retries. `checksum_source`
-	// is the text load() will verify, which for the JSON config ends before the trailing newline.
-	bool												write_config_file(const std::string &path, std::string body, const std::string &checksum_source);
-
 	// Has any value been modified since the config.ini has been last saved or loaded?
 	bool														m_dirty;
-	// After a failed write, save_due() is false for the next ten seconds, so the
-	// idle handler does not repeat a hopeless write on every event.
-	std::chrono::steady_clock::time_point						m_retry_save_at{};
 	// Original version found in the ini file before it was overwritten
 	Semver                                                      m_orig_version;
 	// Whether the existing version is before system profiles & configuration updating

src/libslic3r/CMakeLists.txt

@@ -306,8 +306,6 @@ set(lisbslic3r_sources
     Geometry/VoronoiUtils.cpp
     Geometry/VoronoiUtils.hpp
     Geometry/VoronoiVisualUtils.hpp
-    InstanceLock.cpp
-    InstanceLock.hpp
     Int128.hpp
     KDTreeIndirect.hpp
     Layer.cpp
@@ -357,7 +355,6 @@ set(lisbslic3r_sources
     Optimize/Optimizer.hpp
     Orient.cpp
     Orient.hpp
-    ParallelResolve.hpp
     ParameterUtils.cpp
     ParameterUtils.hpp
     pchheader.cpp

src/libslic3r/ClipperUtils.cpp

@@ -1,7 +1,11 @@
+#include <algorithm>
+#include <cmath>
 #include <limits>
 #include <numeric>
 #include <unordered_map>
 
+#include <tbb/parallel_for.h>
+
 #include "ClipperUtils.hpp"
 #include "Geometry.hpp"
 #include "ShortestPath.hpp"
@@ -813,6 +817,69 @@ Slic3r::ExPolygons intersection_ex(const Slic3r::Surfaces &subject, const Slic3r
     { return _clipper_ex(ClipperLib::ctIntersection, ClipperUtils::SurfacesProvider(subject), ClipperUtils::SurfacesProvider(clip), do_safety_offset); }
 Slic3r::ExPolygons intersection_ex(const Slic3r::SurfacesPtr &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset)
     { return _clipper_ex(ClipperLib::ctIntersection, ClipperUtils::SurfacesPtrProvider(subject), ClipperUtils::ExPolygonsProvider(clip), do_safety_offset); }
+
+namespace ClipperUtils {
+    std::vector<ExPolygonsTile> tile_expolygons(const ExPolygons &expolygons, size_t per_tile)
+    {
+        BoundingBox              extent;
+        std::vector<BoundingBox> bboxes;
+        bboxes.reserve(expolygons.size());
+        for (const ExPolygon &expoly : expolygons) {
+            bboxes.emplace_back(get_extents(expoly));
+            extent.merge(bboxes.back());
+        }
+        if (! extent.defined)
+            return {};
+        const int     tiles  = std::clamp(int(std::sqrt(double(expolygons.size()) / double(std::max<size_t>(per_tile, 1)))), 1, 32);
+        const Point   size   = extent.size();
+        const coord_t tile_w = std::max<coord_t>(1, size.x() / tiles + 1), tile_h = std::max<coord_t>(1, size.y() / tiles + 1);
+        std::vector<ExPolygonsTile> out(size_t(tiles * tiles));
+        for (size_t i = 0; i < expolygons.size(); ++ i) {
+            const Point c = bboxes[i].center();
+            ExPolygonsTile &tile = out[size_t(std::clamp(int((c.y() - extent.min.y()) / tile_h), 0, tiles - 1) * tiles +
+                                              std::clamp(int((c.x() - extent.min.x()) / tile_w), 0, tiles - 1))];
+            tile.members.emplace_back(i);
+            tile.bbox.merge(bboxes[i]);
+        }
+        out.erase(std::remove_if(out.begin(), out.end(), [](const ExPolygonsTile &tile) { return tile.members.empty(); }), out.end());
+        return out;
+    }
+}
+
+static Slic3r::ExPolygons clipper_ex_by_piece(ClipperLib::ClipType clipType, const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset)
+{
+    // A few dozen subject ExPolygons to a tile, each tile one ClipperLib call with the clip cut to the tile's box.
+    const std::vector<ClipperUtils::ExPolygonsTile> tiles = ClipperUtils::tile_expolygons(subject, 32);
+    std::vector<BoundingBox> clip_bboxes;
+    clip_bboxes.reserve(clip.size());
+    for (const Polygon &polygon : clip)
+        clip_bboxes.emplace_back(get_extents(polygon));
+
+    std::vector<Slic3r::ExPolygons> out_tiles(tiles.size());
+    tbb::parallel_for(size_t(0), tiles.size(), [&](size_t tile_idx) {
+        const ClipperUtils::ExPolygonsTile &tile = tiles[tile_idx];
+        Slic3r::ExPolygons local_subject;
+        local_subject.reserve(tile.members.size());
+        for (size_t i : tile.members)
+            local_subject.emplace_back(subject[i]);
+        // Grown so that the cut edges of the clip stay clear of the subject, also after the safety offset.
+        const BoundingBox bbox = tile.bbox.inflated(SCALED_EPSILON);
+        Polygons local_clip;
+        for (size_t i = 0; i < clip.size(); ++i)
+            if (clip_bboxes[i].overlap(bbox))
+                if (Polygon clipped = ClipperUtils::clip_clipper_polygon_with_subject_bbox(clip[i], bbox); ! clipped.empty())
+                    local_clip.emplace_back(std::move(clipped));
+        out_tiles[tile_idx] = _clipper_ex(clipType, ClipperUtils::ExPolygonsProvider(local_subject), ClipperUtils::PolygonsProvider(local_clip), do_safety_offset);
+    });
+    Slic3r::ExPolygons out;
+    for (Slic3r::ExPolygons &out_tile : out_tiles)
+        append(out, std::move(out_tile));
+    return out;
+}
+Slic3r::ExPolygons diff_ex_by_piece(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset)
+    { return clipper_ex_by_piece(ClipperLib::ctDifference, subject, clip, do_safety_offset); }
+Slic3r::ExPolygons intersection_ex_by_piece(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset)
+    { return clipper_ex_by_piece(ClipperLib::ctIntersection, subject, clip, do_safety_offset); }
 // May be used to "heal" unusual models (3DLabPrints etc.) by providing fill_type (pftEvenOdd, pftNonZero, pftPositive, pftNegative).
 Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, ClipperLib::PolyFillType fill_type)
     { return _clipper_ex(ClipperLib::ctUnion, ClipperUtils::PolygonsProvider(subject), ClipperUtils::EmptyPathsProvider(), ApplySafetyOffset::No, fill_type); }

src/libslic3r/ClipperUtils.hpp

@@ -2,6 +2,7 @@
 #define slic3r_ClipperUtils_hpp_
 
 #include "libslic3r.h"
+#include "BoundingBox.hpp"
 #include "clipper.hpp"
 #include "ExPolygon.hpp"
 #include "Polygon.hpp"
@@ -321,6 +322,15 @@ namespace ClipperUtils {
     [[nodiscard]] Polygons clip_clipper_polygons_with_subject_bbox(const ExPolygon &src, const BoundingBox &bbox, const bool get_entire_polygons = false);
     [[nodiscard]] Polygons clip_clipper_polygons_with_subject_bbox(const ExPolygons &src, const BoundingBox &bbox, const bool get_entire_polygons = false);
 
+    // Splits ExPolygons into tiles by the centres of their boxes, about `per_tile` of them to a tile, to run ClipperLib on a
+    // layer of many pieces tile by tile. Returns the non-empty tiles, each with the indices of its ExPolygons and their box.
+    struct ExPolygonsTile
+    {
+        BoundingBox         bbox;
+        std::vector<size_t> members;
+    };
+    [[nodiscard]] std::vector<ExPolygonsTile> tile_expolygons(const ExPolygons &expolygons, size_t per_tile);
+
     }
 
 // Perform union of input polygons using the non-zero rule, convert to ExPolygons.
@@ -518,6 +528,11 @@ Slic3r::ExPolygons intersection_ex(const Slic3r::Surfaces &subject, const Slic3r
 Slic3r::ExPolygons intersection_ex(const Slic3r::Surfaces &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::ExPolygons intersection_ex(const Slic3r::Surfaces &subject, const Slic3r::Surfaces &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::ExPolygons intersection_ex(const Slic3r::SurfacesPtr &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
+// diff_ex() / intersection_ex() of the subject split into tiles, each against only the part of the clip near it, the tiles in
+// parallel. The same area as the operation on the whole subject when its ExPolygons do not overlap, and much faster for a
+// subject of thousands of pieces spread over a layer: ClipperLib slows down with the number of edges crossing a scan line.
+Slic3r::ExPolygons diff_ex_by_piece(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
+Slic3r::ExPolygons intersection_ex_by_piece(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::Polylines  intersection_pl(const Slic3r::Polylines &subject, const Slic3r::Polygon &clip);
 Slic3r::Polylines  intersection_pl(const Slic3r::Polyline &subject, const Slic3r::ExPolygon &clip);
 Slic3r::Polylines  intersection_pl(const Slic3r::Polylines &subject, const Slic3r::ExPolygon &clip);

src/libslic3r/Config.cpp

@@ -849,19 +849,6 @@ ConfigSubstitutions ConfigBase::load_from_json(const std::string &file, ForwardC
     return std::move(substitutions_ctxt.substitutions);
 }
 
-// Case-insensitive compare of a JSON key against a fixed ASCII one, without
-// boost::iequals, whose std::locale() takes a lock the whole process shares in the
-// MSVC runtime.
-static bool ascii_iequals(const std::string &key, const char *literal)
-{
-    auto lower = [](char c) { return (c >= 'A' && c <= 'Z') ? char(c - 'A' + 'a') : c; };
-    size_t i = 0;
-    for (; i < key.size() && literal[i] != '\0'; ++ i)
-        if (lower(key[i]) != lower(literal[i]))
-            return false;
-    return i == key.size() && literal[i] == '\0';
-}
-
 int ConfigBase::load_from_json(const std::string &file, ConfigSubstitutionContext& substitution_context, bool load_inherits_to_config, std::map<std::string, std::string>& key_values, std::string& reason)
 {
     json j;
@@ -929,44 +916,44 @@ int ConfigBase::load_from_json(const std::string &file, ConfigSubstitutionContex
         }
         //parse the json elements
         for (auto it = j.begin(); it != j.end(); it++) {
-            if (ascii_iequals(it.key(), BBL_JSON_KEY_VERSION)) {
+            if (boost::iequals(it.key(),BBL_JSON_KEY_VERSION)) {
                 key_values.emplace(BBL_JSON_KEY_VERSION, it.value());
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_IS_CUSTOM)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_IS_CUSTOM)) {
                 //skip it
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_NAME)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_NAME)) {
                 key_values.emplace(BBL_JSON_KEY_NAME, it.value());
                 if (it.value() == "project_settings")
                     is_project_settings = true;
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_URL)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_URL)) {
                 key_values.emplace(BBL_JSON_KEY_URL, it.value());
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_TYPE)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_TYPE)) {
                 key_values.emplace(BBL_JSON_KEY_TYPE, it.value());
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_SETTING_ID)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_SETTING_ID)) {
                 key_values.emplace(BBL_JSON_KEY_SETTING_ID, it.value());
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_FILAMENT_ID)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_FILAMENT_ID)) {
                 key_values.emplace(BBL_JSON_KEY_FILAMENT_ID, it.value());
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_FROM)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_FROM)) {
                 key_values.emplace(BBL_JSON_KEY_FROM, it.value());
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_DESCRIPTION)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_DESCRIPTION)) {
                 key_values.emplace(BBL_JSON_KEY_DESCRIPTION, it.value());
             }
-            else if (ascii_iequals(it.key(), BBL_JSON_KEY_INSTANTIATION)) {
+            else if (boost::iequals(it.key(), BBL_JSON_KEY_INSTANTIATION)) {
                 key_values.emplace(BBL_JSON_KEY_INSTANTIATION, it.value());
             }
-            else if (!load_inherits_to_config && ascii_iequals(it.key(), BBL_JSON_KEY_INHERITS)) {
+            else if (!load_inherits_to_config && boost::iequals(it.key(), BBL_JSON_KEY_INHERITS)) {
                 key_values.emplace(BBL_JSON_KEY_INHERITS, it.value());
             }
-            else if (!load_inherits_to_config && ascii_iequals(it.key(), BBL_JSON_KEY_INCLUDES)) {
+            else if (!load_inherits_to_config && boost::iequals(it.key(), BBL_JSON_KEY_INCLUDES)) {
                 key_values.emplace(BBL_JSON_KEY_INCLUDES, it.value().dump());
-            } else if (ascii_iequals(it.key(), ORCA_JSON_KEY_RENAMED_FROM)) {
+            } else if (boost::iequals(it.key(), ORCA_JSON_KEY_RENAMED_FROM)) {
                 key_values.emplace(ORCA_JSON_KEY_RENAMED_FROM, it.value());
             } else {
                 t_config_option_key opt_key = it.key();
@@ -1538,10 +1525,12 @@ void ConfigBase::save_to_json(const std::string &file, const std::string &name,
     // Serialize first: if that throws (invalid UTF-8), the existing file stays untouched.
     std::ostringstream ss;
     this->save_to_json(ss, name, from, version);
-    if (const std::error_code ec = write_file_atomically(file, ss.str()))
-        BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << boost::format(": failed to save config to %1%: %2%") % file % ec.message();
-    else
-        BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << ":" <<__LINE__ << boost::format(", saved config to %1%\n")%file;
+    boost::nowide::ofstream c;
+    c.open(file, std::ios::out | std::ios::trunc);
+    c << ss.str();
+    c.close();
+
+    BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << ":" <<__LINE__ << boost::format(", saved config to %1%\n")%file;
 }
 
 void ConfigBase::save_to_json(std::ostream &os, const std::string &name, const std::string &from, const std::string &version, bool replace_invalid_utf8) const

src/libslic3r/Fill/Fill.cpp

@@ -9,6 +9,8 @@
 #include "../PrintConfig.hpp"
 #include "../Surface.hpp"
 
+#include <tbb/parallel_for.h>
+
 #include "AABBTreeLines.hpp"
 #include "ExtrusionEntity.hpp"
 #include "Fill.hpp"
@@ -630,24 +632,28 @@ void split_solid_surface(size_t layer_id, const SurfaceFill &fill, ExPolygons &n
     if (!line_based_pattern) {
         const coord_t scaled_spacing = scaled<coord_t>(fill.params.spacing);
 
-        for (const ExPolygon &expolygon : fill.expolygons) {
+        // Each expolygon is split on its own, so they run in parallel and are collected in their original order.
+        std::vector<std::pair<ExPolygons, ExPolygons>> split_parts(fill.expolygons.size()); // normal, narrow
+        tbb::parallel_for(size_t(0), fill.expolygons.size(), [&](size_t idx) {
+            const ExPolygon &expolygon = fill.expolygons[idx];
             Polygons filled_area = to_polygons(expolygon);
 
             // "Core" area: open (erode+dilate) to drop thin features, then clamp back to the original polygon.
             Polygons inner_area  = intersection(filled_area, opening(filled_area, scaled_spacing, scaled_spacing));
 
             if (inner_area.empty()) {
-                narrow_infill.emplace_back(expolygon);
-                continue;
+                split_parts[idx].second.emplace_back(expolygon);
+                return;
             }
 
             ExPolygons inner_ex = union_ex(inner_area);
             ExPolygons expolys{expolygon};
-            ExPolygons narrow_ex = diff_ex(expolys, inner_ex);
-            ExPolygons normal_ex = intersection_ex(expolys, inner_ex);
-
-            append(normal_infill, normal_ex); // normal infill area
-            append(narrow_infill, narrow_ex); // narrow infill area
+            split_parts[idx].second = diff_ex(expolys, inner_ex);         // narrow infill area
+            split_parts[idx].first  = intersection_ex(expolys, inner_ex); // normal infill area
+        });
+        for (auto &[normal_ex, narrow_ex] : split_parts) {
+            append(normal_infill, std::move(normal_ex));
+            append(narrow_infill, std::move(narrow_ex));
         }
 
         return;
@@ -669,7 +675,10 @@ void split_solid_surface(size_t layer_id, const SurfaceFill &fill, ExPolygons &n
     }
     const double aligning_angle = -base_angle + PI;
 
-	for (const ExPolygon &expolygon : fill.expolygons) {
+    // Each expolygon is reconstructed on its own, so they run in parallel and are collected in their original order.
+    std::vector<Polygons> split_reconstructed(fill.expolygons.size());
+    tbb::parallel_for(size_t(0), fill.expolygons.size(), [&](size_t expolygon_idx) {
+        const ExPolygon &expolygon = fill.expolygons[expolygon_idx];
         Polygons filled_area = to_polygons(expolygon);
         polygons_rotate(filled_area, aligning_angle);
         BoundingBox bb = get_extents(filled_area);
@@ -800,8 +809,10 @@ void split_solid_surface(size_t layer_id, const SurfaceFill &fill, ExPolygons &n
             }
         }
 
-        polygons_append(normal_fill_areas, reconstructed_area);
-    }
+        split_reconstructed[expolygon_idx] = std::move(reconstructed_area);
+    });
+    for (Polygons &reconstructed_area : split_reconstructed)
+        polygons_append(normal_fill_areas, std::move(reconstructed_area));
 
     polygons_rotate(normal_fill_areas, -aligning_angle);
 
@@ -1409,7 +1420,15 @@ void Layer::make_fills(FillAdaptive::Octree* adaptive_fill_octree, FillAdaptive:
             // Orca: Reuse the body origin used for bridge anchoring, resetting it for each surface.
             f->set_bounding_box(infill_bounding_box(*this, surface_fill, expoly, bbox));
 
-            f->no_overlap_expolygons = intersection_ex(surface_fill.no_overlap_expolygons, ExPolygons() = {expoly}, ApplySafetyOffset::Yes);
+            // Only the part of the layer-wide no-overlap area under this expolygon matters, so clip it to the
+            // expolygon's box first (padded past the safety offset, which grows the clip side). The result is
+            // identical; the cost is not: a layer split into many small fills, e.g. by colour painting,
+            // otherwise intersects every one of them with the whole layer.
+            BoundingBox no_overlap_bbox = get_extents(expoly);
+            no_overlap_bbox.offset(SCALED_EPSILON);
+            f->no_overlap_expolygons = intersection_ex(
+                ClipperUtils::clip_clipper_polygons_with_subject_bbox(surface_fill.no_overlap_expolygons, no_overlap_bbox),
+                ExPolygons() = {expoly}, ApplySafetyOffset::Yes);
             if (params.symmetric_infill_y_axis) {
                 params.symmetric_y_axis = f->extended_object_bounding_box().center().x();
                 expoly.symmetric_y(params.symmetric_y_axis);

src/libslic3r/GCode/OrderingStrategies.cpp

@@ -10,6 +10,7 @@
 #include <limits>
 #include <numeric>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -134,15 +135,79 @@ bool tsp_remove_crossings(std::vector<size_t>& path, const Points& centers)
         return {std::numeric_limits<size_t>::max(), std::numeric_limits<size_t>::max()};
     };
 
+    // For many islands, the same scan with the edges binned in a uniform grid over their boxes, so each edge is only tested against the edges sharing a
+    // cell with it - two edges whose boxes overlap always do. It returns the same crossing as the all-pairs scan
+    // (smallest i, then smallest j), so the result is unchanged; with thousands of islands on a layer the all-pairs
+    // scan, repeated after every reversal, never finished. Rebuilding the grid costs more than it saves on small inputs.
+    constexpr size_t grid_min_size = 500;
+    BoundingBox extent;
+    for (size_t idx : path)
+        extent.merge(centers[idx]);
+    const int     grid_n = std::clamp(int(std::sqrt(double(pn))), 1, 256);
+    const coord_t cell_w = std::max<coord_t>(1, (extent.max.x() - extent.min.x()) / grid_n + 1);
+    const coord_t cell_h = std::max<coord_t>(1, (extent.max.y() - extent.min.y()) / grid_n + 1);
+    const auto    for_cells = [&](const Point& a, const Point& b, auto&& fn) {
+        const int x0 = int((std::min(a.x(), b.x()) - extent.min.x()) / cell_w), x1 = int((std::max(a.x(), b.x()) - extent.min.x()) / cell_w);
+        const int y0 = int((std::min(a.y(), b.y()) - extent.min.y()) / cell_h), y1 = int((std::max(a.y(), b.y()) - extent.min.y()) / cell_h);
+        for (int y = y0; y <= y1; ++y)
+            for (int x = x0; x <= x1; ++x)
+                fn(y * grid_n + x);
+    };
+    std::vector<std::vector<size_t>> edge_cells(size_t(grid_n) * grid_n);
+
+    auto find_crossing_grid = [&]() -> std::pair<size_t, size_t> {
+        for (std::vector<size_t>& cell : edge_cells)
+            cell.clear();
+        for (size_t j = 0; j < n_edges; ++j)
+            for_cells(centers[path[j]], centers[path[(j + 1) % pn]], [&](int cell) { edge_cells[cell].emplace_back(j); });
+
+        for (size_t i = 0; i < n_edges; ++i) {
+            const Point& ai = centers[path[i]];
+            const Point& bi = centers[path[(i + 1) % pn]];
+
+            size_t first_j = std::numeric_limits<size_t>::max();
+            for_cells(ai, bi, [&](int cell) {
+                for (size_t j : edge_cells[cell]) {
+                    if (j < i + 2 || j >= first_j) continue;
+                    // Skip the (0, pn-1) pair: edges (0,1) and (pn-1,0) share node 0.
+                    if (i == 0 && j == pn - 1) continue;
+
+                    const Point& aj = centers[path[j]];
+                    const Point& bj = centers[path[(j + 1) % pn]];
+
+                    if (!bboxes_overlap(ai, bi, aj, bj)) continue;
+                    if (Geometry::segments_intersect(ai, bi, aj, bj))
+                        first_j = j;
+                }
+            });
+            if (first_j != std::numeric_limits<size_t>::max())
+                return {i, first_j};
+        }
+        return {std::numeric_limits<size_t>::max(), std::numeric_limits<size_t>::max()};
+    };
+
     // Process crossings one at a time: find first, reverse it, restart scan.
     // Cap iterations to prevent infinite loops on collinear/overlapping segments.
     int max_iters = static_cast<int>(pn * pn);
     bool improved = false;
+    // Reversing between two segments that only touch or overlap along a line need not remove the intersection, and on
+    // islands laid out on a regular grid (a tiled texture, an array of parts) the loop cycled through the same orderings
+    // until the pn * pn cap - effectively forever. Stop as soon as an ordering repeats: until then this is the same loop.
+    std::unordered_set<uint64_t> seen_paths;
+    const auto path_hash = [&path]() {
+        uint64_t h = 1469598103934665603ull; // FNV-1a
+        for (size_t idx : path)
+            h = (h ^ uint64_t(idx)) * 1099511628211ull;
+        return h;
+    };
+    seen_paths.insert(path_hash());
     while (max_iters-- > 0) {
-        auto [ci, cj] = find_crossing();
+        auto [ci, cj] = pn >= grid_min_size ? find_crossing_grid() : find_crossing();
         if (ci == std::numeric_limits<size_t>::max()) break;
         improved = true;
         std::reverse(path.begin() + ci + 1, path.begin() + cj + 1);
+        if (!seen_paths.insert(path_hash()).second)
+            break;
     }
     return improved;
 }

src/libslic3r/GCode/SeamPlacer.cpp

@@ -8,6 +8,7 @@
 #include <boost/log/trivial.hpp>
 #include <random>
 #include <algorithm>
+#include <limits>
 #include <queue>
 #include <unordered_map>
 
@@ -1178,21 +1179,21 @@ std::optional<std::pair<size_t, size_t>> SeamPlacer::find_next_seam_in_layer(
     const size_t layer_idx, const float max_distance,
     const SeamPlacerImpl::SeamComparator &comparator) const {
   using namespace SeamPlacerImpl;
-  std::vector<size_t> nearby_points_indices = find_nearby_points(*layers[layer_idx].points_tree, projected_position,
-                                                                 max_distance);
-
-  if (nearby_points_indices.empty()) {
-    return {};
-  }
-
-  size_t best_nearby_point_index = nearby_points_indices[0];
-  size_t nearest_point_index = nearby_points_indices[0];
-
-  // Now find best nearby point, nearest point, and corresponding indices
-  for (const size_t &nearby_point_index : nearby_points_indices) {
+  // Find the best nearby point and the nearest one. A layer of a fine relief has tens of thousands of candidates within
+  // the radius, so they are looked at as the search finds them rather than collected into a vector first.
+  constexpr size_t none = std::numeric_limits<size_t>::max();
+  size_t best_nearby_point_index = none;
+  size_t nearest_point_index = none;
+  visit_nearby_points(*layers[layer_idx].points_tree, projected_position, max_distance,
+                      [&layers, &comparator, &projected_position, layer_idx, &best_nearby_point_index, &nearest_point_index]
+                      (size_t nearby_point_index) {
+    if (best_nearby_point_index == none) {
+      // The first point found starts both, as the first of the collected ones did.
+      best_nearby_point_index = nearest_point_index = nearby_point_index;
+    }
     const SeamCandidate &point = layers[layer_idx].points[nearby_point_index];
     if (point.perimeter.finalized) {
-      continue; // skip over finalized perimeters, try to find some that is not finalized
+      return; // skip over finalized perimeters, try to find some that is not finalized
     }
     if (comparator.is_first_better(point, layers[layer_idx].points[best_nearby_point_index],
                                    projected_position.head<2>())
@@ -1204,6 +1205,10 @@ std::optional<std::pair<size_t, size_t>> SeamPlacer::find_next_seam_in_layer(
         || layers[layer_idx].points[nearest_point_index].perimeter.finalized) {
       nearest_point_index = nearby_point_index;
     }
+  });
+
+  if (best_nearby_point_index == none) {
+    return {};
   }
 
   const SeamCandidate &best_nearby_point = layers[layer_idx].points[best_nearby_point_index];

src/libslic3r/InstanceLock.cpp

@@ -1,165 +0,0 @@
-#include "InstanceLock.hpp"
-
-#include <map>
-#include <memory>
-#include <system_error>
-#include <thread>
-
-#include <boost/filesystem.hpp>
-#include <boost/log/trivial.hpp>
-#include <boost/nowide/fstream.hpp>
-#ifdef _WIN32
-#include <boost/interprocess/sync/file_lock.hpp>
-#include <boost/nowide/convert.hpp>
-#else
-#include <cerrno>
-#include <fcntl.h>
-#include <sys/file.h>
-#include <unistd.h>
-#endif
-
-namespace Slic3r {
-
-#ifdef _WIN32
-// LockFileEx, held by this handle alone.
-using NativeFileLock = boost::interprocess::file_lock;
-#else
-// flock(2) rather than an fcntl lock: it belongs to this open file description,
-// so any other code in the process that opens and closes the lock file, as a
-// backup or an export walking the data dir might, cannot drop it. An fcntl
-// lock would go with the first such close.
-class NativeFileLock
-{
-public:
-    explicit NativeFileLock(const char *path) : m_fd(::open(path, O_RDWR | O_CREAT | O_CLOEXEC, 0644))
-    {
-        if (m_fd < 0)
-            throw std::system_error(errno, std::generic_category(), path);
-    }
-    ~NativeFileLock() { ::close(m_fd); }
-    bool try_lock()
-    {
-        if (::flock(m_fd, LOCK_EX | LOCK_NB) == 0)
-            return true;
-        // A signal (a child exiting, for one) interrupts the call like any other; the caller polls again.
-        if (errno == EWOULDBLOCK || errno == EINTR)
-            return false;
-        throw std::system_error(errno, std::generic_category(), "flock");
-    }
-    void unlock() { ::flock(m_fd, LOCK_UN); }
-private:
-    int m_fd;
-};
-#endif
-
-// One slot per lock file, shared by every guard in the process: one lock
-// object per path behind a mutex is what makes the guard re-entrant and safe
-// to use from the preset sync thread and the GUI thread at once. The lock
-// file is opened by the outermost guard and closed when it goes, so the file
-// is never held open between guards: whatever is at the path is what gets
-// locked, and a data dir can be removed once nothing is saving into it. The
-// file is kept rather than deleted on release because the lock state lives in
-// the kernel on the open file, and deleting it would let a third instance
-// lock a fresh file while the second still holds the old one.
-struct InstanceLock::Slot
-{
-    std::recursive_mutex mutex;
-    // Non-null exactly while this process holds the file lock.
-    std::unique_ptr<NativeFileLock> file_lock;
-    int  depth{0};
-    // Until this point, after a guard could not open, lock or wait out the
-    // file, guards do not touch it.
-    std::chrono::steady_clock::time_point cooldown_until{};
-};
-
-InstanceLock::Slot &InstanceLock::slot_for(const std::string &lock_file_path)
-{
-    // Never freed: a save during static destruction still needs its slot.
-    static auto *registry_mutex = new std::mutex();
-    static auto *registry       = new std::map<std::string, std::unique_ptr<Slot>>();
-
-    std::lock_guard<std::mutex> guard(*registry_mutex);
-    std::unique_ptr<Slot> &slot = (*registry)[lock_file_path];
-    if (! slot)
-        slot = std::make_unique<Slot>();
-    return *slot;
-}
-
-// Starts the cool-down. Called with the slot mutex held.
-void InstanceLock::defer(Slot &slot, const std::string &reason)
-{
-    slot.cooldown_until = std::chrono::steady_clock::now() + cooldown;
-    BOOST_LOG_TRIVIAL(warning) << reason << "; proceeding without the lock for the next " << cooldown.count() << " ms";
-}
-
-// Creates the lock file if needed and opens it, or starts the cool-down.
-// Called with the slot mutex held.
-bool InstanceLock::open_lock_file(Slot &slot, const std::string &lock_file_path)
-{
-    try {
-#ifdef _WIN32
-        // The lock opens an existing file; created once, on the first miss.
-        const std::wstring wide_path = boost::nowide::widen(lock_file_path);
-        try {
-            slot.file_lock = std::make_unique<NativeFileLock>(wide_path.c_str());
-        } catch (const std::exception &) {
-            boost::nowide::ofstream(lock_file_path, std::ios::app).close();
-            slot.file_lock = std::make_unique<NativeFileLock>(wide_path.c_str());
-        }
-#else
-        slot.file_lock = std::make_unique<NativeFileLock>(lock_file_path.c_str());
-#endif
-        return true;
-    } catch (const std::exception &e) {
-        defer(slot, "Cannot open lock file " + lock_file_path + ": " + e.what() + " (check its owner and permissions)");
-        return false;
-    }
-}
-
-InstanceLock::InstanceLock(const std::string &lock_file_path, std::chrono::milliseconds timeout)
-{
-    if (lock_file_path.empty())
-        return;
-    m_slot       = &slot_for(lock_file_path);
-    m_slot_guard = std::unique_lock<std::recursive_mutex>(m_slot->mutex);
-    const auto now = std::chrono::steady_clock::now();
-    if (m_slot->depth == 0 && now >= m_slot->cooldown_until && open_lock_file(*m_slot, lock_file_path)) {
-        const auto deadline = now + timeout;
-        bool       taken    = false;
-        for (;;) {
-            try {
-                if ((taken = m_slot->file_lock->try_lock()))
-                    break;
-            } catch (const std::exception &e) {
-                defer(*m_slot, "Cannot lock " + lock_file_path + ": " + e.what());
-                break;
-            }
-            if (std::chrono::steady_clock::now() >= deadline) {
-                defer(*m_slot, "Another instance has held " + lock_file_path + " for over " + std::to_string(timeout.count()) + " ms");
-                break;
-            }
-            std::this_thread::sleep_for(std::chrono::milliseconds(5));
-        }
-        if (! taken)
-            m_slot->file_lock.reset();
-    }
-    // Counted last, so a throw above leaves the slot exactly as it was found.
-    ++ m_slot->depth;
-    m_locked = m_slot->file_lock != nullptr;
-}
-
-InstanceLock::~InstanceLock()
-{
-    if (m_slot == nullptr)
-        return;
-    if (-- m_slot->depth == 0 && m_slot->file_lock) {
-        try {
-            m_slot->file_lock->unlock();
-        } catch (const std::exception &e) {
-            BOOST_LOG_TRIVIAL(warning) << "Cannot unlock instance lock: " << e.what();
-        }
-        m_slot->file_lock.reset();
-    }
-}
-
-} // namespace Slic3r

src/libslic3r/InstanceLock.hpp

@@ -1,60 +0,0 @@
-#pragma once
-
-#include <chrono>
-#include <mutex>
-#include <string>
-
-namespace Slic3r {
-
-// Scoped write lock on a file shared by every running instance of the
-// application, such as the app config or the user preset directory: threads
-// of this process are serialised through a recursive mutex, other processes
-// through an advisory OS file lock on `lock_file_path`. The lock file is
-// created on first use and kept; the OS releases the lock when its holder
-// exits, so a crashed instance never leaves a stale lock behind.
-//
-// Best effort: when the lock file cannot be opened or locked, or another
-// instance still holds it after `timeout`, the guard keeps only the in-process
-// mutex, locked() reports false and the write proceeds, since a hung instance
-// must never block another one from saving. For `cooldown` afterwards guards
-// leave the file alone. The wait for the in-process mutex is bounded only by
-// the longest critical section, so a guard covers a few file operations and
-// nothing slower.
-//
-// Lock order: the preset collection mutex may be held when a guard is taken
-// (set_sync_info_and_save() calls save_info() under it), never the reverse;
-// that is why the guards sit at the leaf readers and writers and why a guard
-// must not be added around save_user_presets(), which takes the collection
-// mutex through delete_preset().
-class InstanceLock
-{
-public:
-    // Long against a critical section of milliseconds, short against the GUI
-    // thread, which is where most guards are taken.
-    static constexpr std::chrono::milliseconds default_timeout{1000};
-    // Long enough that a holder stuck in a debugger does not cost a stall per
-    // save; mutable so tests can shorten it.
-    static inline std::chrono::milliseconds cooldown{10000};
-
-    // An empty path makes the guard a no-op.
-    explicit InstanceLock(const std::string &lock_file_path, std::chrono::milliseconds timeout = default_timeout);
-    ~InstanceLock();
-
-    InstanceLock(const InstanceLock &) = delete;
-    InstanceLock &operator=(const InstanceLock &) = delete;
-
-    // True while this process holds the cross-process file lock.
-    bool locked() const { return m_locked; }
-
-private:
-    struct Slot;
-    static Slot &slot_for(const std::string &lock_file_path);
-    static bool  open_lock_file(Slot &slot, const std::string &lock_file_path);
-    static void  defer(Slot &slot, const std::string &reason);
-
-    Slot *m_slot{nullptr};
-    std::unique_lock<std::recursive_mutex> m_slot_guard;
-    bool  m_locked{false};
-};
-
-} // namespace Slic3r

src/libslic3r/KDTreeIndirect.hpp

@@ -313,6 +313,36 @@ std::vector<size_t> find_nearby_points(const KDTreeIndirectType &kdtree, const P
     return visitor.result;
 }
 
+// Visits the points within max_distance of center, in the order find_nearby_points() would collect them, and hands
+// each of them to `visitor_fn` instead of returning them all: a search over a dense set spends more on collecting the
+// points into a vector than on the search itself, and its caller usually keeps only a few of them.
+template<typename KDTreeIndirectType, typename PointType, typename VisitorFn>
+void visit_nearby_points(const KDTreeIndirectType &kdtree, const PointType &center,
+                         const typename KDTreeIndirectType::CoordType &max_distance, VisitorFn visitor_fn)
+{
+    using CoordType = typename KDTreeIndirectType::CoordType;
+
+    struct Visitor {
+        const KDTreeIndirectType &kdtree;
+        const PointType           center;
+        const CoordType           max_distance_squared;
+        VisitorFn                 visitor_fn;
+
+        unsigned int operator()(size_t idx, size_t dimension) {
+            auto dist = CoordType(0);
+            for (size_t i = 0; i < KDTreeIndirectType::NumDimensions; ++i) {
+                CoordType d = center[i] - kdtree.coordinate(idx, i);
+                dist += d * d;
+            }
+            if (dist < max_distance_squared)
+                visitor_fn(idx);
+            return kdtree.descent_mask(center[dimension], max_distance_squared, idx, dimension);
+        }
+    } visitor { kdtree, center, max_distance * max_distance, visitor_fn };
+
+    kdtree.visit(visitor);
+}
+
 template<typename KDTreeIndirectType, typename PointType>
 std::vector<size_t> find_nearby_points(const KDTreeIndirectType &kdtree, const PointType &center,
                                        const typename KDTreeIndirectType::CoordType& max_distance)

src/libslic3r/LayerRegion.cpp

@@ -72,10 +72,11 @@ void LayerRegion::slices_to_fill_surfaces_clipped()
         by_surface[size_t(surface.surface_type)].emplace_back(&surface);
     // Trim surfaces by the fill_boundaries.
     this->fill_surfaces.surfaces.clear();
+    const Polygons fill_boundaries = to_polygons(this->fill_expolygons);
     for (size_t surface_type = 0; surface_type < size_t(stCount); ++ surface_type) {
         const SurfacesPtr &this_surfaces = by_surface[surface_type];
         if (! this_surfaces.empty())
-            this->fill_surfaces.append(intersection_ex(this_surfaces, this->fill_expolygons), SurfaceType(surface_type));
+            this->fill_surfaces.append(intersection_ex_by_piece(to_expolygons(this_surfaces), fill_boundaries), SurfaceType(surface_type));
     }
 }
 

src/libslic3r/LocalesUtils.cpp

@@ -13,19 +13,8 @@
 namespace Slic3r {
 
 
-// How many setters this thread holds, so the ones nested in another can skip
-// setlocale, which takes a lock the whole process shares on Windows.
-static thread_local int s_numeric_locale_depth = 0;
-
 CNumericLocalesSetter::CNumericLocalesSetter()
 {
-    // Nested in another setter on this thread, whose "C" the separator check
-    // confirms is still set.
-    if (s_numeric_locale_depth > 0 && is_decimal_separator_point()) {
-        m_nested = true;
-        ++ s_numeric_locale_depth;
-        return;
-    }
 #ifdef _WIN32
     _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
     m_orig_numeric_locale = std::setlocale(LC_NUMERIC, nullptr);
@@ -40,17 +29,12 @@ CNumericLocalesSetter::CNumericLocalesSetter()
     m_new_locale = newlocale(LC_NUMERIC_MASK, "C", m_new_locale);
     uselocale(m_new_locale);
 #endif
-    // Counted last, since the destructor does not run for a constructor that throws.
-    ++ s_numeric_locale_depth;
 }
 
 
 
 CNumericLocalesSetter::~CNumericLocalesSetter()
 {
-    -- s_numeric_locale_depth;
-    if (m_nested)
-        return;
 #ifdef _WIN32
     std::setlocale(LC_NUMERIC, m_orig_numeric_locale.data());
 #else

src/libslic3r/LocalesUtils.hpp

@@ -19,13 +19,8 @@ class CNumericLocalesSetter {
 public:
     CNumericLocalesSetter();
     ~CNumericLocalesSetter();
-    // A copy would restore the locale twice, and count down once more than up.
-    CNumericLocalesSetter(const CNumericLocalesSetter&) = delete;
-    CNumericLocalesSetter& operator=(const CNumericLocalesSetter&) = delete;
 
 private:
-    // Inside another setter on this thread, which does the setting and restoring.
-    bool m_nested { false };
 #ifdef _WIN32
     std::string m_orig_numeric_locale;
 #else

src/libslic3r/MultiMaterialSegmentation.cpp

@@ -8,6 +8,7 @@
 #include "MutablePolygon.hpp"
 #include "format.hpp"
 
+#include <numeric>
 #include <utility>
 #include <unordered_set>
 
@@ -1311,10 +1312,15 @@ static inline std::vector<std::vector<ExPolygons>> segmentation_top_and_bottom_l
     }
 #endif // MM_SEGMENTATION_DEBUG_TOP_BOTTOM
 
-    // When the upper surface of an object is occluded, it should no longer be considered the upper surface
+    // When the upper surface of an object is occluded, it should no longer be considered the upper surface.
+    // Every (colour, layer) pair is trimmed on its own, so they all run at once: the painted faces of a finely
+    // textured part project hundreds of thousands of triangles onto one layer, which used to be trimmed serially.
     {
-        for (size_t extruder_idx = 0; extruder_idx < num_facets_states; ++extruder_idx) {
-            for (size_t layer_idx = 0; layer_idx < layers.size(); ++layer_idx) {
+        const size_t occluded_pairs = num_facets_states * layers.size();
+        tbb::parallel_for(tbb::blocked_range<size_t>(0, occluded_pairs), [&](const tbb::blocked_range<size_t> &range) {
+            for (size_t pair_idx = range.begin(); pair_idx < range.end(); ++pair_idx) {
+                const size_t extruder_idx = pair_idx / layers.size();
+                const size_t layer_idx    = pair_idx % layers.size();
                 if (!top_raw[extruder_idx].empty() && !top_raw[extruder_idx][layer_idx].empty() && layer_idx + 1 < layers.size()) {
                     top_raw[extruder_idx][layer_idx] = diff(top_raw[extruder_idx][layer_idx], input_expolygons[layer_idx + 1]);
                 }
@@ -1322,7 +1328,7 @@ static inline std::vector<std::vector<ExPolygons>> segmentation_top_and_bottom_l
                     bottom_raw[extruder_idx][layer_idx] = diff(bottom_raw[extruder_idx][layer_idx], input_expolygons[layer_idx - 1]);
                 }
             }
-        }
+        });
     }
 
     std::vector<std::vector<ExPolygons>> triangles_by_color_bottom(num_facets_states);
@@ -1378,13 +1384,62 @@ static inline std::vector<std::vector<ExPolygons>> segmentation_top_and_bottom_l
         return out;
     };
 
+    // Projects a painted top or bottom face `ex` of layer `layer_idx` onto the shell layers below or above it (in
+    // `shell_layers`, nearest first), one more perimeter in on each, stopping at the first layer where nothing is left.
+    // Only the slices within the deepest offset of `ex` (three times that with the miter joins) decide the result, so the
+    // work is done per tile of `ex`'s ExPolygons on the slices cut to the tile's box grown by that much: the same result, but
+    // each ClipperLib call stays the size of a tile rather than of a layer cut through a fine relief, and the tiles run in
+    // parallel.
+    const auto project_to_shells = [&input_expolygons](const ExPolygons &ex, size_t layer_idx, const std::vector<size_t> &shell_layers,
+                                                       const LayerColorStat &stat, std::vector<ExPolygons> &dst, size_t dst_offset) {
+        std::vector<float> offsets(shell_layers.size());
+        float              offset = 0.f;
+        for (size_t i = 0; i < shell_layers.size(); ++i) {
+            //BBS: offset width should be 2*spacing to avoid too narrow area which has overlap of wall line
+            offset -= (stat.extrusion_spacing + stat.extrusion_width);
+            offsets[i] = offset;
+        }
+        if (offsets.empty())
+            return;
+        const coord_t reach = coord_t(std::ceil(DefaultMiterLimit * std::abs(offsets.back()))) + 10 * SCALED_EPSILON;
+        const std::vector<ClipperUtils::ExPolygonsTile> tiles = ClipperUtils::tile_expolygons(ex, 16);
+        // [shell layer][tile]
+        std::vector<std::vector<ExPolygons>> shells(shell_layers.size(), std::vector<ExPolygons>(tiles.size()));
+        tbb::parallel_for(size_t(0), tiles.size(), [&](size_t tile_idx) {
+            const ClipperUtils::ExPolygonsTile &tile = tiles[tile_idx];
+            const BoundingBox                   bbox = tile.bbox.inflated(reach);
+            ExPolygons                          tile_ex;
+            tile_ex.reserve(tile.members.size());
+            for (size_t i : tile.members)
+                tile_ex.emplace_back(ex[i]);
+            Polygons layer_slices_trimmed = ClipperUtils::clip_clipper_polygons_with_subject_bbox(input_expolygons[layer_idx], bbox);
+            for (size_t i = 0; i < shell_layers.size() && ! layer_slices_trimmed.empty(); ++i) {
+                const ExPolygons trimmed = intersection_ex(layer_slices_trimmed, ClipperUtils::clip_clipper_polygons_with_subject_bbox(input_expolygons[shell_layers[i]], bbox));
+                shells[i][tile_idx]  = opening_ex(intersection_ex(tile_ex, offset_ex(trimmed, offsets[i])), stat.small_region_threshold);
+                layer_slices_trimmed = to_polygons(trimmed);
+            }
+        });
+        for (size_t i = 0; i < shell_layers.size(); ++i) {
+            bool empty = true;
+            for (ExPolygons &shell : shells[i])
+                if (! shell.empty()) {
+                    append(dst[shell_layers[i] + dst_offset], std::move(shell));
+                    empty = false;
+                }
+            if (empty)
+                break;
+        }
+    };
+
     tbb::parallel_for(tbb::blocked_range<size_t>(0, num_layers, granularity), [&granularity, &num_layers, &num_facets_states, &layer_color_stat, &top_raw, &triangles_by_color_top,
-                                                                               &throw_on_cancel_callback, &input_expolygons, &bottom_raw, &triangles_by_color_bottom,
+                                                                               &throw_on_cancel_callback, &bottom_raw, &triangles_by_color_bottom, &project_to_shells,
                                                                                &shell_triangles_by_color_top, &shell_triangles_by_color_bottom](const tbb::blocked_range<size_t> &range) {
         size_t group_idx   = range.begin() / granularity;
         size_t layer_idx_offset = (group_idx & 1) * num_layers;
         for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx) {
-            for (size_t color_idx = 0; color_idx < num_facets_states; ++color_idx) {
+            // Each colour writes only its own vectors, so the colours run in parallel: a painted top or bottom face
+            // projects onto a single layer, which otherwise did all of its colours on one thread.
+            tbb::parallel_for(size_t(0), size_t(num_facets_states), [&](size_t color_idx) {
                 throw_on_cancel_callback();
                 LayerColorStat stat = layer_color_stat(layer_idx, color_idx);
                 if (std::vector<Polygons> &top = top_raw[color_idx]; ! top.empty() && ! top[layer_idx].empty())
@@ -1393,18 +1448,10 @@ static inline std::vector<std::vector<ExPolygons>> segmentation_top_and_bottom_l
                         top_ex = opening_ex(top_ex, stat.small_region_threshold);
                         if (! top_ex.empty()) {
                             append(triangles_by_color_top[color_idx][layer_idx + layer_idx_offset], top_ex);
-                            float offset = 0.f;
-                            ExPolygons layer_slices_trimmed = input_expolygons[layer_idx];
-                            for (int last_idx = int(layer_idx) - 1; last_idx > std::max(int(layer_idx - stat.top_shell_layers), int(0)); --last_idx) {
-                                //BBS: offset width should be 2*spacing to avoid too narrow area which has overlap of wall line
-                                //offset -= stat.extrusion_width ;
-                                offset -= (stat.extrusion_spacing + stat.extrusion_width);
-                                layer_slices_trimmed = intersection_ex(layer_slices_trimmed, input_expolygons[last_idx]);
-                                ExPolygons last = opening_ex(intersection_ex(top_ex, offset_ex(layer_slices_trimmed, offset)), stat.small_region_threshold);
-                                if (last.empty())
-                                    break;
-                                append(shell_triangles_by_color_top[color_idx][last_idx + layer_idx_offset], std::move(last));
-                            }
+                            std::vector<size_t> shell_layers;
+                            for (int last_idx = int(layer_idx) - 1; last_idx > std::max(int(layer_idx - stat.top_shell_layers), int(0)); --last_idx)
+                                shell_layers.emplace_back(size_t(last_idx));
+                            project_to_shells(top_ex, layer_idx, shell_layers, stat, shell_triangles_by_color_top[color_idx], layer_idx_offset);
                         }
                     }
                 if (std::vector<Polygons> &bottom = bottom_raw[color_idx]; ! bottom.empty() && ! bottom[layer_idx].empty())
@@ -1413,21 +1460,13 @@ static inline std::vector<std::vector<ExPolygons>> segmentation_top_and_bottom_l
                         bottom_ex = opening_ex(bottom_ex, stat.small_region_threshold);
                         if (! bottom_ex.empty()) {
                             append(triangles_by_color_bottom[color_idx][layer_idx + layer_idx_offset], bottom_ex);
-                            float offset = 0.f;
-                            ExPolygons layer_slices_trimmed = input_expolygons[layer_idx];
-                            for (size_t last_idx = layer_idx + 1; last_idx < std::min(layer_idx + stat.bottom_shell_layers, num_layers); ++last_idx) {
-                                //BBS: offset width should be 2*spacing to avoid too narrow area which has overlap of wall line
-                                //offset -= stat.extrusion_width;
-                                offset -= (stat.extrusion_spacing + stat.extrusion_width);
-                                layer_slices_trimmed = intersection_ex(layer_slices_trimmed, input_expolygons[last_idx]);
-                                ExPolygons last = opening_ex(intersection_ex(bottom_ex, offset_ex(layer_slices_trimmed, offset)), stat.small_region_threshold);
-                                if (last.empty())
-                                    break;
-                                append(shell_triangles_by_color_bottom[color_idx][last_idx + layer_idx_offset], std::move(last));
-                            }
+                            std::vector<size_t> shell_layers;
+                            for (size_t last_idx = layer_idx + 1; last_idx < std::min(layer_idx + stat.bottom_shell_layers, num_layers); ++last_idx)
+                                shell_layers.emplace_back(last_idx);
+                            project_to_shells(bottom_ex, layer_idx, shell_layers, stat, shell_triangles_by_color_bottom[color_idx], layer_idx_offset);
                         }
                     }
-            }
+            });
         }
     });
 
@@ -1437,22 +1476,25 @@ static inline std::vector<std::vector<ExPolygons>> segmentation_top_and_bottom_l
                                                                   &shell_triangles_by_color_top, &shell_triangles_by_color_bottom](const tbb::blocked_range<size_t> &range) {
         for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx) {
             throw_on_cancel_callback();
-            ExPolygons painted_exploys;
-            for (size_t color_idx = 0; color_idx < triangles_by_color_merged.size(); ++color_idx) {
+            // The per-colour unions below are independent of each other, so they run in parallel (a painted top or
+            // bottom face puts all of its colours on one layer); whatever combines the colours stays in colour order.
+            const auto merge_colour_union = [&](size_t color_idx) {
                 auto &self = triangles_by_color_merged[color_idx][layer_idx];
                 append(self, std::move(triangles_by_color_bottom[color_idx][layer_idx]));
                 append(self, std::move(triangles_by_color_bottom[color_idx][layer_idx + num_layers]));
                 append(self, std::move(triangles_by_color_top[color_idx][layer_idx]));
                 append(self, std::move(triangles_by_color_top[color_idx][layer_idx + num_layers]));
                 self = union_ex(self);
+            };
+            tbb::parallel_for(size_t(0), triangles_by_color_merged.size(), merge_colour_union);
 
-                append(painted_exploys, self);
-            }
-
+            ExPolygons painted_exploys;
+            for (size_t color_idx = 0; color_idx < triangles_by_color_merged.size(); ++color_idx)
+                append(painted_exploys, triangles_by_color_merged[color_idx][layer_idx]);
             painted_exploys = union_ex(painted_exploys);
 
             //BBS: merge the top and bottom shell layers
-            for (size_t color_idx = 0; color_idx < triangles_by_color_merged.size(); ++color_idx) {
+            tbb::parallel_for(size_t(0), triangles_by_color_merged.size(), [&](size_t color_idx) {
                 auto &self = triangles_by_color_merged[color_idx][layer_idx];
 
                 auto top_area = diff_ex(union_ex(shell_triangles_by_color_top[color_idx][layer_idx],
@@ -1466,7 +1508,7 @@ static inline std::vector<std::vector<ExPolygons>> segmentation_top_and_bottom_l
                 append(self, top_area);
                 append(self, bottom_area);
                 self = union_ex(self);
-            }
+            });
             // Trim one region by the other if some of the regions overlap.
             ExPolygons painted_regions;
             for (size_t color_idx = 1; color_idx < triangles_by_color_merged.size(); ++color_idx) {
@@ -1833,7 +1875,69 @@ static void remove_multiple_edges_in_vertices(MMU_Graph &graph, const std::vecto
     }
 }
 
-static std::vector<std::vector<ExPolygons>> merge_segmented_layers(const std::vector<std::vector<ExPolygons>> &segmented_regions,
+
+// Finds the islands (layer ExPolygons) a region piece overlaps. A top or bottom region is projected from the neighbouring
+// layers and may reach past the island it belongs to, or over several islands.
+class IslandLocator
+{
+public:
+    explicit IslandLocator(const ExPolygons &islands) : m_islands(islands)
+    {
+        m_bboxes.reserve(islands.size());
+        for (const ExPolygon &island : islands) {
+            m_bboxes.emplace_back(get_extents(island));
+            m_extent.merge(m_bboxes.back());
+        }
+        if (!m_extent.defined)
+            return;
+        const Point size = m_extent.size();
+        m_cell_w = std::max<coord_t>(1, size.x() / GRID + 1);
+        m_cell_h = std::max<coord_t>(1, size.y() / GRID + 1);
+        m_grid.assign(GRID * GRID, {});
+        for (size_t i = 0; i < m_bboxes.size(); ++i)
+            for_cells(m_bboxes[i], [&](int cell) { m_grid[cell].emplace_back(i); });
+    }
+
+    void find(const ExPolygon &piece, std::vector<size_t> &out) const
+    {
+        out.clear();
+        const BoundingBox bbox = get_extents(piece);
+        if (!m_extent.defined || !m_extent.overlap(bbox))
+            return;
+        for_cells(bbox, [&](int cell) {
+            for (size_t i : m_grid[cell])
+                if (m_bboxes[i].overlap(bbox))
+                    out.emplace_back(i);
+        });
+        sort_remove_duplicates(out);
+        if (out.size() > 1)
+            out.erase(std::remove_if(out.begin(), out.end(), [&](size_t i) {
+                const BoundingBox common(m_bboxes[i].min.cwiseMax(bbox.min), m_bboxes[i].max.cwiseMin(bbox.max));
+                return intersection(ClipperUtils::clip_clipper_polygons_with_subject_bbox(piece, common.inflated(SCALED_EPSILON)),
+                                    ClipperUtils::clip_clipper_polygons_with_subject_bbox(m_islands[i], common.inflated(SCALED_EPSILON))).empty();
+            }), out.end());
+    }
+
+private:
+    static constexpr int GRID = 64;
+    template<typename Fn> void for_cells(const BoundingBox &bb, Fn &&fn) const
+    {
+        const int x0 = std::clamp(int((bb.min.x() - m_extent.min.x()) / m_cell_w), 0, GRID - 1), x1 = std::clamp(int((bb.max.x() - m_extent.min.x()) / m_cell_w), 0, GRID - 1);
+        const int y0 = std::clamp(int((bb.min.y() - m_extent.min.y()) / m_cell_h), 0, GRID - 1), y1 = std::clamp(int((bb.max.y() - m_extent.min.y()) / m_cell_h), 0, GRID - 1);
+        for (int y = y0; y <= y1; ++y)
+            for (int x = x0; x <= x1; ++x)
+                fn(y * GRID + x);
+    }
+
+    const ExPolygons                &m_islands;
+    std::vector<BoundingBox>         m_bboxes;
+    BoundingBox                      m_extent;
+    coord_t                          m_cell_w = 1, m_cell_h = 1;
+    std::vector<std::vector<size_t>> m_grid;
+};
+
+static std::vector<std::vector<ExPolygons>> merge_segmented_layers(const std::vector<ExPolygons>              &input_expolygons,
+                                                                   const std::vector<std::vector<ExPolygons>> &segmented_regions,
                                                                    std::vector<std::vector<ExPolygons>>      &&top_and_bottom_layers,
                                                                    const size_t                                num_facets_states,
                                                                    const std::function<void()>                &throw_on_cancel_callback)
@@ -1844,33 +1948,91 @@ static std::vector<std::vector<ExPolygons>> merge_segmented_layers(const std::ve
     assert(!top_and_bottom_layers.size() || num_facets_states == top_and_bottom_layers.size());
 
     BOOST_LOG_TRIVIAL(debug) << "Print object segmentation - Merging segmented layers in parallel - Begin";
-    tbb::parallel_for(tbb::blocked_range<size_t>(0, num_layers), [&segmented_regions, &top_and_bottom_layers, &segmented_regions_merged, &num_facets_states, &throw_on_cancel_callback](const tbb::blocked_range<size_t> &range) {
+    // Every region of a layer is merged together with the regions of the islands it overlaps, and the islands are further
+    // apart than the dimple removal below reaches, so this gives the same result as merging the layer at once. On a layer
+    // cut through a fine relief every region shares thousands of hole contours with every other, and ClipperLib, splitting
+    // and re-linking one huge polygon over and over, took anything up to half an hour for a layer; per island each operation
+    // stays the size of the island, and the islands run in parallel.
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, num_layers), [&](const tbb::blocked_range<size_t> &range) {
         for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++layer_idx) {
             assert(segmented_regions[layer_idx].size() == num_facets_states);
-            // Zero is skipped because it is the default color of the volume
+            throw_on_cancel_callback();
+            // Group the islands joined by a region overlapping several of them; the last group takes the regions lying
+            // outside every island.
+            const ExPolygons   &islands = input_expolygons[layer_idx];
+            const IslandLocator locator(islands);
+            std::vector<size_t> parent(islands.size() + 1);
+            std::iota(parent.begin(), parent.end(), 0);
+            const auto root = [&parent](size_t i) {
+                while (parent[i] != i)
+                    i = parent[i] = parent[parent[i]];
+                return i;
+            };
+            // Islands of every piece: side regions of colours 1.., then top/bottom regions of colours 0..
+            std::vector<const ExPolygon *> pieces;
+            for (size_t extruder_id = 1; extruder_id < num_facets_states; ++extruder_id)
+                for (const ExPolygon &piece : segmented_regions[layer_idx][extruder_id])
+                    pieces.emplace_back(&piece);
+            if (!top_and_bottom_layers.empty())
+                for (size_t color_idx = 0; color_idx < num_facets_states; ++color_idx)
+                    for (const ExPolygon &piece : top_and_bottom_layers[color_idx][layer_idx])
+                        pieces.emplace_back(&piece);
+            std::vector<std::vector<size_t>> overlapped(pieces.size());
+            tbb::parallel_for(size_t(0), pieces.size(), [&](size_t i) { locator.find(*pieces[i], overlapped[i]); });
+            std::vector<size_t> piece_island(pieces.size());
+            for (size_t i = 0; i < pieces.size(); ++i) {
+                piece_island[i] = overlapped[i].empty() ? islands.size() : overlapped[i].front();
+                for (size_t island : overlapped[i])
+                    parent[root(island)] = root(piece_island[i]);
+            }
+            std::vector<size_t> bucket_of(parent.size(), size_t(-1));
+            size_t              num_buckets = 0;
+            for (size_t i = 0; i < parent.size(); ++i)
+                if (size_t &b = bucket_of[root(i)]; b == size_t(-1))
+                    b = num_buckets++;
+
+            // [bucket][colour]
+            std::vector<std::vector<ExPolygons>> sides(num_buckets, std::vector<ExPolygons>(num_facets_states));
+            std::vector<std::vector<ExPolygons>> tops(num_buckets, std::vector<ExPolygons>(num_facets_states));
+            size_t                               piece_idx = 0;
+            for (size_t extruder_id = 1; extruder_id < num_facets_states; ++extruder_id)
+                for (const ExPolygon &piece : segmented_regions[layer_idx][extruder_id])
+                    sides[bucket_of[root(piece_island[piece_idx++])]][extruder_id].emplace_back(piece);
+            if (!top_and_bottom_layers.empty())
+                for (size_t color_idx = 0; color_idx < num_facets_states; ++color_idx)
+                    for (const ExPolygon &piece : top_and_bottom_layers[color_idx][layer_idx])
+                        tops[bucket_of[root(piece_island[piece_idx++])]][color_idx].emplace_back(piece);
+
+            // Side regions minus the top/bottom regions of every colour.
+            std::vector<std::vector<ExPolygons>> merged(num_buckets, std::vector<ExPolygons>(num_facets_states));
+            tbb::parallel_for(size_t(0), num_buckets, [&](size_t bucket) {
+                Polygons tops_all;
+                for (const ExPolygons &t : tops[bucket])
+                    polygons_append(tops_all, t);
+                for (size_t extruder_id = 1; extruder_id < num_facets_states; ++extruder_id)
+                    if (!sides[bucket][extruder_id].empty())
+                        merged[bucket][extruder_id] = tops_all.empty() ? std::move(sides[bucket][extruder_id]) :
+                                                                         diff_ex_by_piece(sides[bucket][extruder_id], tops_all);
+            });
+
+            // Then this colour's top/bottom regions, with the dimples removed (#7235) when the layer has side regions left.
             for (size_t extruder_id = 1; extruder_id < num_facets_states; ++extruder_id) {
-                throw_on_cancel_callback();
-                if (!segmented_regions[layer_idx][extruder_id].empty()) {
-                    ExPolygons segmented_regions_trimmed = segmented_regions[layer_idx][extruder_id];
-                    if (!top_and_bottom_layers.empty()) {
-                        for (const std::vector<ExPolygons> &top_and_bottom_by_extruder : top_and_bottom_layers) {
-                            if (!top_and_bottom_by_extruder[layer_idx].empty() && !segmented_regions_trimmed.empty()) {
-                                segmented_regions_trimmed = diff_ex(segmented_regions_trimmed, top_and_bottom_by_extruder[layer_idx]);
-                            }
-                        }
-                    }
-
-                    segmented_regions_merged[layer_idx][extruder_id - 1] = std::move(segmented_regions_trimmed);
-                }
-
-                if (!top_and_bottom_layers.empty() && !top_and_bottom_layers[extruder_id][layer_idx].empty()) {
-                    bool was_top_and_bottom_empty = segmented_regions_merged[layer_idx][extruder_id - 1].empty();
-                    append(segmented_regions_merged[layer_idx][extruder_id - 1], top_and_bottom_layers[extruder_id][layer_idx]);
-
-                    // Remove dimples (#7235) appearing after merging side segmentation of the model with tops and bottoms painted layers.
-                    if (!was_top_and_bottom_empty)
-                        segmented_regions_merged[layer_idx][extruder_id - 1] = offset2_ex(union_ex(segmented_regions_merged[layer_idx][extruder_id - 1]), float(SCALED_EPSILON), -float(SCALED_EPSILON));
+                if (top_and_bottom_layers.empty() || top_and_bottom_layers[extruder_id][layer_idx].empty()) {
+                    for (size_t bucket = 0; bucket < num_buckets; ++bucket)
+                        append(segmented_regions_merged[layer_idx][extruder_id - 1], std::move(merged[bucket][extruder_id]));
+                    continue;
                 }
+                bool was_top_and_bottom_empty = true;
+                for (size_t bucket = 0; bucket < num_buckets && was_top_and_bottom_empty; ++bucket)
+                    was_top_and_bottom_empty = merged[bucket][extruder_id].empty();
+                tbb::parallel_for(size_t(0), num_buckets, [&](size_t bucket) {
+                    ExPolygons &region = merged[bucket][extruder_id];
+                    append(region, tops[bucket][extruder_id]);
+                    if (!was_top_and_bottom_empty && !region.empty())
+                        region = offset2_ex(union_ex(region), float(SCALED_EPSILON), -float(SCALED_EPSILON));
+                });
+                for (size_t bucket = 0; bucket < num_buckets; ++bucket)
+                    append(segmented_regions_merged[layer_idx][extruder_id - 1], std::move(merged[bucket][extruder_id]));
             }
         }
     }); // end of parallel_for
@@ -2157,16 +2319,56 @@ std::vector<std::vector<ExPolygons>> segmentation_by_painting(const PrintObject
 
                 assert(!color_poly.empty());
                 assert(!color_poly.front().empty());
-                if (has_layer_only_one_color(color_poly)) {
-                    // If the whole layer is painted using the same color, it is not needed to construct a Voronoi diagram for the segmentation of this layer.
-                    segmented_regions[layer_idx][size_t(color_poly.front().front().color)] = input_expolygons[layer_idx];
-                } else {
-                    MMU_Graph graph = build_graph(layer_idx, color_poly);
-                    remove_multiple_edges_in_vertices(graph, color_poly);
-                    graph.remove_nodes_with_one_arc();
-                    segmented_regions[layer_idx] = extract_colored_segments(graph, num_facets_states);
-                    //segmented_regions[layer_idx] = extract_colored_segments(color_poly, num_extruders, layer_idx);
+                // Each island (an ExPolygon with its holes) is segmented on its own. Any point of an island is closer to
+                // that island's contours than to any other island's - the way out crosses its own boundary first - so its
+                // Voronoi cells, and with them its colour regions, depend on nothing else. A layer cut through a fine relief
+                // has thousands of islands, and one Voronoi diagram over all of them degenerated into overlapping regions
+                // that every boolean afterwards had to untangle. Per island the diagrams stay small and the islands run in
+                // parallel; an island in a single colour needs no diagram at all.
+                const ExPolygons                      &islands = input_expolygons[layer_idx];
+                std::vector<std::pair<size_t, size_t>> island_contours(islands.size()); // [first, last) into color_poly
+                {
+                    // The same order EdgeGrid::Grid::create() lists the contours in, and so colorize_contours().
+                    size_t idx = 0;
+                    for (size_t island_idx = 0; island_idx < islands.size(); ++island_idx) {
+                        const size_t first = idx;
+                        if (!islands[island_idx].contour.empty())
+                            ++idx;
+                        for (const Polygon &hole : islands[island_idx].holes)
+                            if (!hole.empty())
+                                ++idx;
+                        island_contours[island_idx] = {first, idx};
+                    }
+                    assert(idx == color_poly.size());
                 }
+                std::vector<std::vector<ExPolygons>> island_regions(islands.size());
+                tbb::parallel_for(size_t(0), islands.size(), [&](size_t island_idx) {
+                    const auto [first, last] = island_contours[island_idx];
+                    if (first == last)
+                        return;
+                    const std::vector<ColoredLines> island_poly(color_poly.begin() + first, color_poly.begin() + last);
+                    std::vector<ExPolygons>        &regions = island_regions[island_idx];
+                    if (has_layer_only_one_color(island_poly)) {
+                        regions.assign(num_facets_states, ExPolygons());
+                        regions[size_t(island_poly.front().front().color)].emplace_back(islands[island_idx]);
+                    } else {
+                        MMU_Graph graph = build_graph(layer_idx, island_poly);
+                        remove_multiple_edges_in_vertices(graph, island_poly);
+                        graph.remove_nodes_with_one_arc();
+                        regions = extract_colored_segments(graph, num_facets_states);
+                        // The faces of one colour tile it without overlapping; merged here, where an island is small,
+                        // every later boolean gets a few regions instead of thousands of faces sharing their edges. An
+                        // island with many holes keeps its faces: merged, each colour would be one region with thousands
+                        // of holes, and subtracting from that is far slower than from the faces one at a time.
+                        if (island_poly.size() <= 64)
+                            for (ExPolygons &faces : regions)
+                                if (faces.size() > 1)
+                                    faces = union_ex(faces);
+                    }
+                });
+                for (std::vector<ExPolygons> &regions : island_regions)
+                    for (size_t color_idx = 0; color_idx < regions.size(); ++color_idx)
+                        append(segmented_regions[layer_idx][color_idx], std::move(regions[color_idx]));
 
 #ifdef MM_SEGMENTATION_DEBUG_REGIONS
                 export_regions_to_svg(debug_out_path("3-mm-regions-sides-%d-%d.svg", layer_idx, iRun), segmented_regions[layer_idx], input_expolygons[layer_idx]);
@@ -2189,7 +2391,7 @@ std::vector<std::vector<ExPolygons>> segmentation_by_painting(const PrintObject
         throw_on_cancel_callback();
     }
 
-    std::vector<std::vector<ExPolygons>> segmented_regions_merged = merge_segmented_layers(segmented_regions, std::move(top_and_bottom_layers), num_facets_states, throw_on_cancel_callback);
+    std::vector<std::vector<ExPolygons>> segmented_regions_merged = merge_segmented_layers(input_expolygons, segmented_regions, std::move(top_and_bottom_layers), num_facets_states, throw_on_cancel_callback);
     throw_on_cancel_callback();
 
 #ifdef MM_SEGMENTATION_DEBUG_REGIONS

src/libslic3r/MultiPoint.hpp

@@ -19,11 +19,13 @@ public:
     
     MultiPoint() {}
     MultiPoint(const MultiPoint &other) : points(other.points) {}
-    MultiPoint(MultiPoint &&other) : points(std::move(other.points)) {}
+    MultiPoint(MultiPoint &&other) noexcept : points(std::move(other.points)) {}
     MultiPoint(std::initializer_list<Point> list) : points(list) {}
     explicit MultiPoint(const Points &_points) : points(_points) {}
+    // Without it, the derived classes' move constructors passing std::move(points) here copied them.
+    explicit MultiPoint(Points &&_points) noexcept : points(std::move(_points)) {}
     MultiPoint& operator=(const MultiPoint &other) { points = other.points; return *this; }
-    MultiPoint& operator=(MultiPoint &&other) { points = std::move(other.points); return *this; }
+    MultiPoint& operator=(MultiPoint &&other) noexcept { points = std::move(other.points); return *this; }
     virtual ~MultiPoint() = default;
     void scale(double factor);
     void scale(double factor_x, double factor_y);

src/libslic3r/ParallelResolve.hpp

@@ -1,65 +0,0 @@
-#pragma once
-
-#include <algorithm>
-#include <cstddef>
-#include <type_traits>
-#include <utility>
-#include <variant>
-#include <vector>
-
-#include <tbb/blocked_range.h>
-#include <tbb/parallel_for.h>
-#include <tbb/task_arena.h>
-#include <tbb/task_group.h>
-
-#include "Exception.hpp"
-
-namespace Slic3r {
-
-// A batch of resolved presets, each a whole config, is what resolve_then_commit adds
-// to peak memory, so it stays far below a vendor's preset count and above any core count.
-inline constexpr size_t resolve_batch_size = 64;
-
-// Resolve `count` items that do not depend on each other and install them one at
-// a time.
-//
-// `resolve(i)` runs on any thread and must read only, since the items are
-// resolved side by side. `commit(i, resolved)` is called for every item in index
-// order, on the calling thread, and is where shared state is written.
-//
-// The items are worked through in batches, so what is resolved and held at once
-// does not grow with `count`. An exception from either callable propagates after
-// the batches before it have been committed. A cancellation of the caller's task
-// group, which stops a batch partway without an exception, throws RuntimeError
-// before that batch commits.
-//
-// `ChunkSetup`, when given, is constructed once for each piece of a batch TBB hands
-// out, for per-thread state a resolve would otherwise set up per item, such as the
-// C numeric locale, whose setting takes a lock the whole process shares.
-template<class ChunkSetup = std::monostate, class Resolve, class Commit>
-void resolve_then_commit(size_t count, Resolve resolve, Commit commit)
-{
-    using Resolved = std::invoke_result_t<Resolve&, size_t>;
-
-    std::vector<Resolved> resolved(std::min(count, resolve_batch_size));
-    for (size_t first = 0; first < count; first += resolve_batch_size) {
-        const size_t last = std::min(first + resolve_batch_size, count);
-        // Isolated, so a thread waiting on the batch runs none of the caller's other
-        // tasks before finishing it.
-        tbb::this_task_arena::isolate([&] {
-            tbb::parallel_for(tbb::blocked_range<size_t>(first, last),
-                [&](const tbb::blocked_range<size_t>& range) {
-                    ChunkSetup setup;
-                    (void) setup;
-                    for (size_t i = range.begin(); i < range.end(); ++ i)
-                        resolved[i - first] = resolve(i);
-                });
-        });
-        if (tbb::is_current_task_group_canceling())
-            throw RuntimeError("resolve_then_commit: canceled before the batch was resolved");
-        for (size_t i = first; i < last; ++ i)
-            commit(i, std::move(resolved[i - first]));
-    }
-}
-
-} // namespace Slic3r

src/libslic3r/PerimeterGenerator.cpp

@@ -17,6 +17,8 @@
 #include <cassert>
 #include <unordered_set>
 #include <thread>
+#include <tbb/blocked_range.h>
+#include <tbb/parallel_for.h>
 #include "libslic3r/AABBTreeLines.hpp"
 #include "Print.hpp"
 static const int overhang_sampling_number = 6;
@@ -2481,421 +2483,443 @@ void PerimeterGenerator::process_arachne()
     const bool only_one_wall_first_layer = this->config->only_one_wall_first_layer && has_bottom_shell_layers(*this->config);
     // we need to process each island separately because we might have different
     // extra perimeters for each one
-    for (const Surface& surface : all_surfaces) {
-        coord_t bead_width_0 = ext_perimeter_spacing;
-        // detect how many perimeters must be generated for this island
-        int loop_number = this->config->wall_loops + surface.extra_perimeters - 1; // 0-indexed loops
-        int sparse_infill_density = this->config->sparse_infill_density.value;
-        if (this->config->alternate_extra_wall && this->layer_id % 2 == 1 && !m_spiral_vase && sparse_infill_density > 0) // add alternating extra wall
-            loop_number++;
+    // Each island is independent up to its outputs, so they are generated in parallel - a layer split into thousands
+    // of islands (e.g. by colour painting) otherwise ran on one thread - and the outputs are then committed in the
+    // original island order, which is what the extra overhang perimeters (applied to the last island's loops and to
+    // all fill surfaces so far) depend on.
+    struct ArachneSurfaceResult
+    {
+        ExtrusionEntityCollection loops;
+        bool                      has_loops = false;
+        ExPolygons                infill;
+        ExPolygons                no_overlap;
+    };
+    std::vector<ArachneSurfaceResult> results(all_surfaces.size());
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, all_surfaces.size()), [&](const tbb::blocked_range<size_t> &range) {
+      for (size_t surface_idx = range.begin(); surface_idx < range.end(); ++surface_idx) {
+        const Surface        &surface = all_surfaces[surface_idx];
+        ArachneSurfaceResult &result  = results[surface_idx];
+            coord_t bead_width_0 = ext_perimeter_spacing;
+            // detect how many perimeters must be generated for this island
+            int loop_number = this->config->wall_loops + surface.extra_perimeters - 1; // 0-indexed loops
+            int sparse_infill_density = this->config->sparse_infill_density.value;
+            if (this->config->alternate_extra_wall && this->layer_id % 2 == 1 && !m_spiral_vase && sparse_infill_density > 0) // add alternating extra wall
+                loop_number++;
 
-        // Set the bottommost layer to be one wall
-        const bool is_bottom_layer = (this->layer_id == object_config->raft_layers) ? true : false;
-        if (is_bottom_layer && only_one_wall_first_layer)
-            loop_number = 0;
+            // Set the bottommost layer to be one wall
+            const bool is_bottom_layer = (this->layer_id == object_config->raft_layers) ? true : false;
+            if (is_bottom_layer && only_one_wall_first_layer)
+                loop_number = 0;
 
-        // Orca: set the topmost layer to be one wall according to the config
-        const bool is_topmost_layer = (this->upper_slices == nullptr) ? true : false;
-        if (is_topmost_layer && loop_number > 0 && only_one_wall_top)
-            loop_number = 0;
+            // Orca: set the topmost layer to be one wall according to the config
+            const bool is_topmost_layer = (this->upper_slices == nullptr) ? true : false;
+            if (is_topmost_layer && loop_number > 0 && only_one_wall_top)
+                loop_number = 0;
         
-        auto apply_precise_outer_wall = config->precise_outer_wall && config->wall_sequence == WallSequence::InnerOuter;
-        // Orca: properly adjust offset for the outer wall if precise_outer_wall is enabled.
-        ExPolygons last = offset_ex(surface.expolygon.simplify_p(surface_simplify_resolution),
-                       apply_precise_outer_wall? -float(ext_perimeter_width - ext_perimeter_spacing )
-                                                 : -float(ext_perimeter_width / 2. - ext_perimeter_spacing / 2.));
+            auto apply_precise_outer_wall = config->precise_outer_wall && config->wall_sequence == WallSequence::InnerOuter;
+            // Orca: properly adjust offset for the outer wall if precise_outer_wall is enabled.
+            ExPolygons last = offset_ex(surface.expolygon.simplify_p(surface_simplify_resolution),
+                           apply_precise_outer_wall? -float(ext_perimeter_width - ext_perimeter_spacing )
+                                                     : -float(ext_perimeter_width / 2. - ext_perimeter_spacing / 2.));
         
-        Arachne::WallToolPathsParams input_params = Arachne::make_paths_params(this->layer_id, *object_config, *print_config);
-        // Set params is_top_or_bottom_layer for adjusting short-wall removal sensitivity.
-        input_params.is_top_or_bottom_layer = (is_bottom_layer || is_topmost_layer) ? true : false;
+            Arachne::WallToolPathsParams input_params = Arachne::make_paths_params(this->layer_id, *object_config, *print_config);
+            // Set params is_top_or_bottom_layer for adjusting short-wall removal sensitivity.
+            input_params.is_top_or_bottom_layer = (is_bottom_layer || is_topmost_layer) ? true : false;
 
-        coord_t wall_0_inset = 0;
-        if (apply_precise_outer_wall)
-           wall_0_inset = -coord_t(ext_perimeter_width / 2 - ext_perimeter_spacing / 2);
+            coord_t wall_0_inset = 0;
+            if (apply_precise_outer_wall)
+               wall_0_inset = -coord_t(ext_perimeter_width / 2 - ext_perimeter_spacing / 2);
 
-        //PS: One wall top surface for Arachne
-        ExPolygons top_expolygons;
-        // Calculate how many inner loops remain when TopSurfaces is selected.
-        const int inner_loop_number = (only_one_wall_top && upper_slices != nullptr) ? loop_number - 1 : -1;
+            //PS: One wall top surface for Arachne
+            ExPolygons top_expolygons;
+            // Calculate how many inner loops remain when TopSurfaces is selected.
+            const int inner_loop_number = (only_one_wall_top && upper_slices != nullptr) ? loop_number - 1 : -1;
 
-        // Set one perimeter when TopSurfaces is selected.
-        if (only_one_wall_top && loop_number > 0)
-            loop_number = 0;
+            // Set one perimeter when TopSurfaces is selected.
+            if (only_one_wall_top && loop_number > 0)
+                loop_number = 0;
 
-        Arachne::WallToolPathsParams input_params_tmp = input_params;
+            Arachne::WallToolPathsParams input_params_tmp = input_params;
         
-        Polygons   last_p = to_polygons(last);
-        Arachne::WallToolPaths wallToolPaths(last_p, bead_width_0, perimeter_spacing, coord_t(loop_number + 1),
-                                               wall_0_inset, layer_height, input_params_tmp);
-        std::vector<Arachne::VariableWidthLines>   perimeters = wallToolPaths.getToolPaths();
-        ExPolygons  infill_contour = union_ex(wallToolPaths.getInnerContour());
+            Polygons   last_p = to_polygons(last);
+            Arachne::WallToolPaths wallToolPaths(last_p, bead_width_0, perimeter_spacing, coord_t(loop_number + 1),
+                                                   wall_0_inset, layer_height, input_params_tmp);
+            std::vector<Arachne::VariableWidthLines>   perimeters = wallToolPaths.getToolPaths();
+            ExPolygons  infill_contour = union_ex(wallToolPaths.getInnerContour());
 
-        // Check if there are some remaining perimeters to generate (the number of perimeters
-        // is greater than one together with enabled the single perimeter on top surface feature).
-        if (inner_loop_number >= 0) {
-            assert(upper_slices != nullptr);
+            // Check if there are some remaining perimeters to generate (the number of perimeters
+            // is greater than one together with enabled the single perimeter on top surface feature).
+            if (inner_loop_number >= 0) {
+                assert(upper_slices != nullptr);
 
-            // Infill contour bounding box.
-            BoundingBox infill_contour_bbox = get_extents(infill_contour);
-            infill_contour_bbox.offset(SCALED_EPSILON);
+                // Infill contour bounding box.
+                BoundingBox infill_contour_bbox = get_extents(infill_contour);
+                infill_contour_bbox.offset(SCALED_EPSILON);
             
-            coord_t perimeter_width = this->perimeter_flow.scaled_width();
+                coord_t perimeter_width = this->perimeter_flow.scaled_width();
 
-            // Get top ExPolygons from current infill contour.
-            Polygons upper_slices_clipped;
-            if (object_config->interface_shells) {
-                auto upper_slicer_same_region = to_expolygons(this->upper_slices_same_region->surfaces);
-                upper_slices_clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(upper_slicer_same_region, infill_contour_bbox);
-            } else
-                upper_slices_clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*upper_slices, infill_contour_bbox);
+                // Get top ExPolygons from current infill contour.
+                Polygons upper_slices_clipped;
+                if (object_config->interface_shells) {
+                    auto upper_slicer_same_region = to_expolygons(this->upper_slices_same_region->surfaces);
+                    upper_slices_clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(upper_slicer_same_region, infill_contour_bbox);
+                } else
+                    upper_slices_clipped = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*upper_slices, infill_contour_bbox);
 
-            top_expolygons = diff_ex(infill_contour, upper_slices_clipped);
+                top_expolygons = diff_ex(infill_contour, upper_slices_clipped);
 
-            if (!top_expolygons.empty()) {
-                if (lower_slices != nullptr) {
-                    const float      bridge_offset          = float(std::max<coord_t>(ext_perimeter_spacing, perimeter_width));
-                    const Polygons   lower_slices_clipped   = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*lower_slices, infill_contour_bbox);
-                    const ExPolygons current_slices_bridges = offset_ex(diff_ex(top_expolygons, lower_slices_clipped), bridge_offset);
+                if (!top_expolygons.empty()) {
+                    if (lower_slices != nullptr) {
+                        const float      bridge_offset          = float(std::max<coord_t>(ext_perimeter_spacing, perimeter_width));
+                        const Polygons   lower_slices_clipped   = ClipperUtils::clip_clipper_polygons_with_subject_bbox(*lower_slices, infill_contour_bbox);
+                        const ExPolygons current_slices_bridges = offset_ex(diff_ex(top_expolygons, lower_slices_clipped), bridge_offset);
 
-                    // Remove bridges from top surface polygons.
-                    top_expolygons = diff_ex(top_expolygons, current_slices_bridges);
+                        // Remove bridges from top surface polygons.
+                        top_expolygons = diff_ex(top_expolygons, current_slices_bridges);
+                    }
+
+                    // Filter out areas that are too thin and expand top surface polygons a bit to hide the wall line.
+                    // ORCA: skip if the top surface area is smaller than "min_width_top_surface"
+                    const float top_surface_min_width = std::max<float>(float(ext_perimeter_spacing) / 4.f + scaled<float>(0.00001), float(scale_(config->min_width_top_surface.get_abs_value(unscale_(perimeter_width)))) / 4.f);
+                    // Shrink the polygon to remove the small areas, then expand it back out plus a maragin to hide the wall line a little.
+                    // ORCA: Expand the polygon with half the perimeter width in addition to the contracted amount,
+                    // not the full perimeter width as PS does, to enable thin lettering to print on the top surface without nozzle collisions
+                    // due to thin lines being generated
+                    top_expolygons = offset2_ex(top_expolygons, -top_surface_min_width, top_surface_min_width + float(perimeter_width * 0.85));
+
+                    // Get final top ExPolygons (bridges were excluded above, so they stay walled).
+                    top_expolygons = intersection_ex(top_expolygons, infill_contour);
+
+                    // ORCA: onion the real region (inside the outer wall) so the remaining walls follow the actual
+                    // geometry, then cut away the parts over the top surface. Re-onioning the non-top complement
+                    // instead - the fallback when there is no top fill - walls the top/non-top interface and rings
+                    // top-surface islands with inner walls that don't exist when the feature is disabled.
+                    const bool     clip_walls_over_top = top_fill_replaces_inner_walls(*this->config);
+                    const Polygons inner_region        = to_polygons(offset_ex(clip_walls_over_top ? infill_contour
+                                                                                                   : diff_ex(infill_contour, top_expolygons),
+                                                                              wall_0_inset));
+                    Arachne::WallToolPaths inner_wall_tool_paths(inner_region, perimeter_spacing, perimeter_spacing, coord_t(inner_loop_number + 1), 0, layer_height, input_params_tmp);
+                    std::vector<Arachne::VariableWidthLines> inner_perimeters = inner_wall_tool_paths.getToolPaths();
+
+                    if (clip_walls_over_top) {
+                        Polygons kept_over_top;
+                        clip_inner_walls_over_top(inner_perimeters, top_expolygons, perimeter_width, kept_over_top);
+                        // Route the top fill around the walls kept despite grazing the top.
+                        if (! kept_over_top.empty())
+                            top_expolygons = diff_ex(top_expolygons, kept_over_top);
+                    }
+
+                    // Recalculate indexes of inner perimeters before merging them: they come after the single outer wall.
+                    if (!perimeters.empty())
+                        for (Arachne::VariableWidthLines &inner_perimeter : inner_perimeters)
+                            for (Arachne::ExtrusionLine &el : inner_perimeter)
+                                ++el.inset_idx;
+
+                    perimeters.insert(perimeters.end(), inner_perimeters.begin(), inner_perimeters.end());
+                    infill_contour = union_ex(top_expolygons, inner_wall_tool_paths.getInnerContour());
+                } else {
+                    // There is no top surface ExPolygon, so we call Arachne again with parameters
+                    // like when the single perimeter feature is disabled.
+                    Arachne::WallToolPaths no_single_perimeter_tool_paths(last_p, bead_width_0, perimeter_spacing, coord_t(inner_loop_number + 2), wall_0_inset, layer_height, input_params_tmp);
+                    perimeters     = no_single_perimeter_tool_paths.getToolPaths();
+                    infill_contour = union_ex(no_single_perimeter_tool_paths.getInnerContour());
                 }
-
-                // Filter out areas that are too thin and expand top surface polygons a bit to hide the wall line.
-                // ORCA: skip if the top surface area is smaller than "min_width_top_surface"
-                const float top_surface_min_width = std::max<float>(float(ext_perimeter_spacing) / 4.f + scaled<float>(0.00001), float(scale_(config->min_width_top_surface.get_abs_value(unscale_(perimeter_width)))) / 4.f);
-                // Shrink the polygon to remove the small areas, then expand it back out plus a maragin to hide the wall line a little.
-                // ORCA: Expand the polygon with half the perimeter width in addition to the contracted amount,
-                // not the full perimeter width as PS does, to enable thin lettering to print on the top surface without nozzle collisions
-                // due to thin lines being generated
-                top_expolygons = offset2_ex(top_expolygons, -top_surface_min_width, top_surface_min_width + float(perimeter_width * 0.85));
-
-                // Get final top ExPolygons (bridges were excluded above, so they stay walled).
-                top_expolygons = intersection_ex(top_expolygons, infill_contour);
-
-                // ORCA: onion the real region (inside the outer wall) so the remaining walls follow the actual
-                // geometry, then cut away the parts over the top surface. Re-onioning the non-top complement
-                // instead - the fallback when there is no top fill - walls the top/non-top interface and rings
-                // top-surface islands with inner walls that don't exist when the feature is disabled.
-                const bool     clip_walls_over_top = top_fill_replaces_inner_walls(*this->config);
-                const Polygons inner_region        = to_polygons(offset_ex(clip_walls_over_top ? infill_contour
-                                                                                               : diff_ex(infill_contour, top_expolygons),
-                                                                          wall_0_inset));
-                Arachne::WallToolPaths inner_wall_tool_paths(inner_region, perimeter_spacing, perimeter_spacing, coord_t(inner_loop_number + 1), 0, layer_height, input_params_tmp);
-                std::vector<Arachne::VariableWidthLines> inner_perimeters = inner_wall_tool_paths.getToolPaths();
-
-                if (clip_walls_over_top) {
-                    Polygons kept_over_top;
-                    clip_inner_walls_over_top(inner_perimeters, top_expolygons, perimeter_width, kept_over_top);
-                    // Route the top fill around the walls kept despite grazing the top.
-                    if (! kept_over_top.empty())
-                        top_expolygons = diff_ex(top_expolygons, kept_over_top);
-                }
-
-                // Recalculate indexes of inner perimeters before merging them: they come after the single outer wall.
-                if (!perimeters.empty())
-                    for (Arachne::VariableWidthLines &inner_perimeter : inner_perimeters)
-                        for (Arachne::ExtrusionLine &el : inner_perimeter)
-                            ++el.inset_idx;
-
-                perimeters.insert(perimeters.end(), inner_perimeters.begin(), inner_perimeters.end());
-                infill_contour = union_ex(top_expolygons, inner_wall_tool_paths.getInnerContour());
-            } else {
-                // There is no top surface ExPolygon, so we call Arachne again with parameters
-                // like when the single perimeter feature is disabled.
-                Arachne::WallToolPaths no_single_perimeter_tool_paths(last_p, bead_width_0, perimeter_spacing, coord_t(inner_loop_number + 2), wall_0_inset, layer_height, input_params_tmp);
-                perimeters     = no_single_perimeter_tool_paths.getToolPaths();
-                infill_contour = union_ex(no_single_perimeter_tool_paths.getInnerContour());
             }
-        }
-        //PS
+            //PS
 
-        loop_number = int(perimeters.size()) - 1;
+            loop_number = int(perimeters.size()) - 1;
 
-        #ifdef ARACHNE_DEBUG
-        {
-            static int iRun = 0;
-            export_perimeters_to_svg(debug_out_path("arachne-perimeters-%d-%d.svg", layer_id, iRun++), to_polygons(last), perimeters, union_ex(wallToolPaths.getInnerContour()));
-        }
-#endif
+            #ifdef ARACHNE_DEBUG
+            {
+                static int iRun = 0;
+                export_perimeters_to_svg(debug_out_path("arachne-perimeters-%d-%d.svg", layer_id, iRun++), to_polygons(last), perimeters, union_ex(wallToolPaths.getInnerContour()));
+            }
+    #endif
 
-        // All closed ExtrusionLine should have the same the first and the last point.
-        // But in rare cases, Arachne produce ExtrusionLine marked as closed but without
-        // equal the first and the last point.
-        assert([&perimeters = std::as_const(perimeters)]() -> bool {
-            for (const Arachne::VariableWidthLines& perimeter : perimeters)
-                for (const Arachne::ExtrusionLine& el : perimeter)
-                    if (el.is_closed && el.junctions.front().p != el.junctions.back().p)
-                        return false;
-            return true;
-        }());
+            // All closed ExtrusionLine should have the same the first and the last point.
+            // But in rare cases, Arachne produce ExtrusionLine marked as closed but without
+            // equal the first and the last point.
+            assert([&perimeters = std::as_const(perimeters)]() -> bool {
+                for (const Arachne::VariableWidthLines& perimeter : perimeters)
+                    for (const Arachne::ExtrusionLine& el : perimeter)
+                        if (el.is_closed && el.junctions.front().p != el.junctions.back().p)
+                            return false;
+                return true;
+            }());
 
-        int start_perimeter = int(perimeters.size()) - 1;
-        int end_perimeter = -1;
-        int direction = -1;
+            int start_perimeter = int(perimeters.size()) - 1;
+            int end_perimeter = -1;
+            int direction = -1;
 
-		bool is_outer_wall_first =
-            	this->config->wall_sequence == WallSequence::OuterInner ||
-            	this->config->wall_sequence == WallSequence::InnerOuterInner;
+    		bool is_outer_wall_first =
+                	this->config->wall_sequence == WallSequence::OuterInner ||
+                	this->config->wall_sequence == WallSequence::InnerOuterInner;
         
-        if (layer_id == 0){ // disable inner outer inner algorithm after the first layer
-        	is_outer_wall_first =
-            	this->config->wall_sequence == WallSequence::OuterInner;
-        }
-        if (is_outer_wall_first) {
-            start_perimeter = 0;
-            end_perimeter = int(perimeters.size());
-            direction = 1;
-        }
-
-        std::vector<Arachne::ExtrusionLine*> all_extrusions;
-        for (int perimeter_idx = start_perimeter; perimeter_idx != end_perimeter; perimeter_idx += direction) {
-            if (perimeters[perimeter_idx].empty())
-                continue;
-            for (Arachne::ExtrusionLine& wall : perimeters[perimeter_idx])
-                all_extrusions.emplace_back(&wall);
-        }
-
-        // Find topological order with constraints from extrusions_constrains.
-        std::vector<size_t>              blocked(all_extrusions.size(), 0); // Value indicating how many extrusions it is blocking (preceding extrusions) an extrusion.
-        std::vector<std::vector<size_t>> blocking(all_extrusions.size());   // Each extrusion contains a vector of extrusions that are blocked by this extrusion.
-        std::unordered_map<const Arachne::ExtrusionLine*, size_t> map_extrusion_to_idx;
-        for (size_t idx = 0; idx < all_extrusions.size(); idx++)
-            map_extrusion_to_idx.emplace(all_extrusions[idx], idx);
-
-        auto extrusions_constrains = Arachne::WallToolPaths::getRegionOrder(all_extrusions, is_outer_wall_first);
-        for (auto [before, after] : extrusions_constrains) {
-            auto after_it = map_extrusion_to_idx.find(after);
-            ++blocked[after_it->second];
-            blocking[map_extrusion_to_idx.find(before)->second].emplace_back(after_it->second);
-        }
-
-        std::vector<bool> processed(all_extrusions.size(), false);          // Indicate that the extrusion was already processed.
-        Point             current_position = all_extrusions.empty() ? Point::Zero() : all_extrusions.front()->junctions.front().p; // Some starting position.
-        std::vector<PerimeterGeneratorArachneExtrusion> ordered_extrusions;         // To store our result in. At the end we'll std::swap.
-        ordered_extrusions.reserve(all_extrusions.size());
-
-        while (ordered_extrusions.size() < all_extrusions.size()) {
-            size_t best_candidate = 0;
-            double best_distance_sqr = std::numeric_limits<double>::max();
-            bool   is_best_closed = false;
-
-            std::vector<size_t> available_candidates;
-            for (size_t candidate = 0; candidate < all_extrusions.size(); ++candidate) {
-                if (processed[candidate] || blocked[candidate])
-                    continue; // Not a valid candidate.
-                available_candidates.push_back(candidate);
+            if (layer_id == 0){ // disable inner outer inner algorithm after the first layer
+            	is_outer_wall_first =
+                	this->config->wall_sequence == WallSequence::OuterInner;
+            }
+            if (is_outer_wall_first) {
+                start_perimeter = 0;
+                end_perimeter = int(perimeters.size());
+                direction = 1;
             }
 
-            std::sort(available_candidates.begin(), available_candidates.end(), [&all_extrusions](const size_t a_idx, const size_t b_idx) -> bool {
-                return all_extrusions[a_idx]->is_closed < all_extrusions[b_idx]->is_closed;
-                });
-
-            for (const size_t candidate_path_idx : available_candidates) {
-                auto& path = all_extrusions[candidate_path_idx];
-
-                if (path->junctions.empty()) { // No vertices in the path. Can't find the start position then or really plan it in. Put that at the end.
-                    if (best_distance_sqr == std::numeric_limits<double>::max()) {
-                        best_candidate = candidate_path_idx;
-                        is_best_closed = path->is_closed;
-                    }
+            std::vector<Arachne::ExtrusionLine*> all_extrusions;
+            for (int perimeter_idx = start_perimeter; perimeter_idx != end_perimeter; perimeter_idx += direction) {
+                if (perimeters[perimeter_idx].empty())
                     continue;
+                for (Arachne::ExtrusionLine& wall : perimeters[perimeter_idx])
+                    all_extrusions.emplace_back(&wall);
+            }
+
+            // Find topological order with constraints from extrusions_constrains.
+            std::vector<size_t>              blocked(all_extrusions.size(), 0); // Value indicating how many extrusions it is blocking (preceding extrusions) an extrusion.
+            std::vector<std::vector<size_t>> blocking(all_extrusions.size());   // Each extrusion contains a vector of extrusions that are blocked by this extrusion.
+            std::unordered_map<const Arachne::ExtrusionLine*, size_t> map_extrusion_to_idx;
+            for (size_t idx = 0; idx < all_extrusions.size(); idx++)
+                map_extrusion_to_idx.emplace(all_extrusions[idx], idx);
+
+            auto extrusions_constrains = Arachne::WallToolPaths::getRegionOrder(all_extrusions, is_outer_wall_first);
+            for (auto [before, after] : extrusions_constrains) {
+                auto after_it = map_extrusion_to_idx.find(after);
+                ++blocked[after_it->second];
+                blocking[map_extrusion_to_idx.find(before)->second].emplace_back(after_it->second);
+            }
+
+            std::vector<bool> processed(all_extrusions.size(), false);          // Indicate that the extrusion was already processed.
+            Point             current_position = all_extrusions.empty() ? Point::Zero() : all_extrusions.front()->junctions.front().p; // Some starting position.
+            std::vector<PerimeterGeneratorArachneExtrusion> ordered_extrusions;         // To store our result in. At the end we'll std::swap.
+            ordered_extrusions.reserve(all_extrusions.size());
+
+            while (ordered_extrusions.size() < all_extrusions.size()) {
+                size_t best_candidate = 0;
+                double best_distance_sqr = std::numeric_limits<double>::max();
+                bool   is_best_closed = false;
+
+                std::vector<size_t> available_candidates;
+                for (size_t candidate = 0; candidate < all_extrusions.size(); ++candidate) {
+                    if (processed[candidate] || blocked[candidate])
+                        continue; // Not a valid candidate.
+                    available_candidates.push_back(candidate);
                 }
 
-                const Point candidate_position = path->junctions.front().p;
-                double      distance_sqr = (current_position - candidate_position).cast<double>().norm();
-                if (distance_sqr < best_distance_sqr) { // Closer than the best candidate so far.
-                    if (path->is_closed || (!path->is_closed && best_distance_sqr != std::numeric_limits<double>::max()) || (!path->is_closed && !is_best_closed)) {
-                        best_candidate = candidate_path_idx;
-                        best_distance_sqr = distance_sqr;
-                        is_best_closed = path->is_closed;
+                std::sort(available_candidates.begin(), available_candidates.end(), [&all_extrusions](const size_t a_idx, const size_t b_idx) -> bool {
+                    return all_extrusions[a_idx]->is_closed < all_extrusions[b_idx]->is_closed;
+                    });
+
+                for (const size_t candidate_path_idx : available_candidates) {
+                    auto& path = all_extrusions[candidate_path_idx];
+
+                    if (path->junctions.empty()) { // No vertices in the path. Can't find the start position then or really plan it in. Put that at the end.
+                        if (best_distance_sqr == std::numeric_limits<double>::max()) {
+                            best_candidate = candidate_path_idx;
+                            is_best_closed = path->is_closed;
+                        }
+                        continue;
                     }
+
+                    const Point candidate_position = path->junctions.front().p;
+                    double      distance_sqr = (current_position - candidate_position).cast<double>().norm();
+                    if (distance_sqr < best_distance_sqr) { // Closer than the best candidate so far.
+                        if (path->is_closed || (!path->is_closed && best_distance_sqr != std::numeric_limits<double>::max()) || (!path->is_closed && !is_best_closed)) {
+                            best_candidate = candidate_path_idx;
+                            best_distance_sqr = distance_sqr;
+                            is_best_closed = path->is_closed;
+                        }
+                    }
+                }
+
+                auto& best_path = all_extrusions[best_candidate];
+                ordered_extrusions.push_back({ best_path, best_path->is_contour() });
+                processed[best_candidate] = true;
+                for (size_t unlocked_idx : blocking[best_candidate])
+                    blocked[unlocked_idx]--;
+
+                if (!best_path->junctions.empty()) { //If all paths were empty, the best path is still empty. We don't upate the current position then.
+                    if (best_path->is_closed)
+                        current_position = best_path->junctions[0].p; //We end where we started.
+                    else
+                        current_position = best_path->junctions.back().p; //Pick the other end from where we started.
                 }
             }
 
-            auto& best_path = all_extrusions[best_candidate];
-            ordered_extrusions.push_back({ best_path, best_path->is_contour() });
-            processed[best_candidate] = true;
-            for (size_t unlocked_idx : blocking[best_candidate])
-                blocked[unlocked_idx]--;
+           // printf("New Layer: Layer ID %d\n",layer_id); //debug - new layer
+            if (this->config->wall_sequence == WallSequence::InnerOuterInner && layer_id > 0) { // only enable inner outer inner algorithm after first layer
+                if (ordered_extrusions.size() > 2) { // 3 walls minimum needed to do inner outer inner ordering
+                    int position = 0; // index to run the re-ordering for multiple external perimeters in a single island.
+                    int arr_i, arr_j = 0;    // indexes to run through the walls in the for loops
+                    int outer, first_internal, second_internal, max_internal, current_perimeter; // allocate index values
+                
+                    // To address any remaining scenarios where the outer perimeter contour is not first on the list as arachne sometimes reorders the perimeters when clustering
+                    // for OI mode that is used the basis for IOI
+                    bringContoursToFront(ordered_extrusions);
+                    std::vector<PerimeterGeneratorArachneExtrusion> reordered_extrusions;
+                
+                    // Debug statement to print spacing values:
+                    //printf("External threshold - Ext perimeter: %d Ext spacing: %d Int perimeter: %d Int spacing: %d\n", this->ext_perimeter_flow.scaled_width(),this->ext_perimeter_flow.scaled_spacing(),this->perimeter_flow.scaled_width(), this->perimeter_flow.scaled_spacing());
 
-            if (!best_path->junctions.empty()) { //If all paths were empty, the best path is still empty. We don't upate the current position then.
-                if (best_path->is_closed)
-                    current_position = best_path->junctions[0].p; //We end where we started.
-                else
-                    current_position = best_path->junctions.back().p; //Pick the other end from where we started.
-            }
-        }
-
-       // printf("New Layer: Layer ID %d\n",layer_id); //debug - new layer
-        if (this->config->wall_sequence == WallSequence::InnerOuterInner && layer_id > 0) { // only enable inner outer inner algorithm after first layer
-            if (ordered_extrusions.size() > 2) { // 3 walls minimum needed to do inner outer inner ordering
-                int position = 0; // index to run the re-ordering for multiple external perimeters in a single island.
-                int arr_i, arr_j = 0;    // indexes to run through the walls in the for loops
-                int outer, first_internal, second_internal, max_internal, current_perimeter; // allocate index values
+                    // Get searching thresholds. For an external perimeter we take the external perimeter spacing/2 plus the internal perimeter spacing/2 and expand by the factor
+                    // rounding errors. When precise wall is enabled, the external perimeter full spacing is used.
+                    coord_t threshold_external = (apply_precise_outer_wall)
+                        // Precise outer wall ⇒ use “full external spacing”
+                        ? ( this->ext_perimeter_flow.scaled_spacing()
+                            + this->perimeter_flow.scaled_spacing()/2.0 )
+                        // Normal ⇒ half ext spacing + half int spacing
+                        : ( this->ext_perimeter_flow.scaled_spacing()/2.0
+                            + this->perimeter_flow.scaled_spacing()/2.0 );
                 
-                // To address any remaining scenarios where the outer perimeter contour is not first on the list as arachne sometimes reorders the perimeters when clustering
-                // for OI mode that is used the basis for IOI
-                bringContoursToFront(ordered_extrusions);
-                std::vector<PerimeterGeneratorArachneExtrusion> reordered_extrusions;
+                    // For the intenal perimeter threshold, the distance is the internal perimeter spacing expanded by the factor to cover rounding errors.
+                    coord_t threshold_internal = this->perimeter_flow.scaled_spacing();
                 
-                // Debug statement to print spacing values:
-                //printf("External threshold - Ext perimeter: %d Ext spacing: %d Int perimeter: %d Int spacing: %d\n", this->ext_perimeter_flow.scaled_width(),this->ext_perimeter_flow.scaled_spacing(),this->perimeter_flow.scaled_width(), this->perimeter_flow.scaled_spacing());
-
-                // Get searching thresholds. For an external perimeter we take the external perimeter spacing/2 plus the internal perimeter spacing/2 and expand by the factor
-                // rounding errors. When precise wall is enabled, the external perimeter full spacing is used.
-                coord_t threshold_external = (apply_precise_outer_wall)
-                    // Precise outer wall ⇒ use “full external spacing”
-                    ? ( this->ext_perimeter_flow.scaled_spacing()
-                        + this->perimeter_flow.scaled_spacing()/2.0 )
-                    // Normal ⇒ half ext spacing + half int spacing
-                    : ( this->ext_perimeter_flow.scaled_spacing()/2.0
-                        + this->perimeter_flow.scaled_spacing()/2.0 );
+                    // Re-order extrusions based on distance
+                    // Alorithm will aggresively optimise for the appearance of the outermost perimeter
+                    ordered_extrusions = reorderPerimetersByProximity(ordered_extrusions,threshold_external,threshold_internal );
+                    reordered_extrusions = ordered_extrusions; // copy them into the reordered extrusions vector to allow for IOI operations to be performed below without altering the base ordered extrusions list.
                 
-                // For the intenal perimeter threshold, the distance is the internal perimeter spacing expanded by the factor to cover rounding errors.
-                coord_t threshold_internal = this->perimeter_flow.scaled_spacing();
-                
-                // Re-order extrusions based on distance
-                // Alorithm will aggresively optimise for the appearance of the outermost perimeter
-                ordered_extrusions = reorderPerimetersByProximity(ordered_extrusions,threshold_external,threshold_internal );
-                reordered_extrusions = ordered_extrusions; // copy them into the reordered extrusions vector to allow for IOI operations to be performed below without altering the base ordered extrusions list.
-                
-                // Now start the sandwich mode wall re-ordering using the reordered_extrusions as the basis
-                // scan to find the external perimeter, first internal, second internal and last perimeter in the island.
-                // We then advance the position index to move to the second island and continue until there are no more
-                // perimeters left.
-                while (position < reordered_extrusions.size()) {
-                    outer = first_internal = second_internal = current_perimeter = -1; // initialise all index values to -1
-                    max_internal = reordered_extrusions.size()-1; // initialise the maximum internal perimeter to the last perimeter on the extrusion list
-                    // run through the walls to get the index values that need re-ordering until the first one for each
-                    // is found. Start at "position" index to enable the for loop to iterate for multiple external
-                    // perimeters in a single island
-                    // printf("Reorder Loop. Position %d, extrusion list size: %d, Outer index %d, inner index %d, second inner index %d\n", position, reordered_extrusions.size(),outer,first_internal,second_internal);
-                    for (arr_i = position; arr_i < reordered_extrusions.size(); ++arr_i) {
-                        // printf("Perimeter: extrusion inset index %d, ordered extrusions array position %d\n",reordered_extrusions[arr_i].extrusion->inset_idx, arr_i);
-                        switch (reordered_extrusions[arr_i].extrusion->inset_idx) {
-                            case 0: // external perimeter
-                                if (outer == -1)
-                                    outer = arr_i;
-                                break;
-                            case 1: // first internal wall
-                                if (first_internal==-1 && arr_i>outer && outer!=-1){
-                                    first_internal = arr_i;
-                                }
-                                break;
-                            case 2: // second internal wall
-                                if (second_internal == -1 && arr_i > first_internal && outer!=-1){
-                                    second_internal = arr_i;
-                                }
-                                break;
-                        }
-                        if(outer >-1 && first_internal>-1 && reordered_extrusions[arr_i].extrusion->inset_idx == 0){  // found a new external perimeter after we've found at least a first internal perimeter to re-order.
-                                                                                                                      // This means we entered a new island.
-                            arr_i=arr_i-1; //step back one perimeter
-                            max_internal = arr_i; // new maximum internal perimeter is now this as we have found a new external perimeter, hence a new island.
-                            break; // exit the for loop
-                        }
-                    }
-                    
-                    // printf("Layer ID %d, Outer index %d, inner index %d, second inner index %d, maximum internal perimeter %d \n",layer_id,outer,first_internal,second_internal, max_internal);
-                    if (outer > -1 && first_internal > -1 && second_internal > -1) { // found all three perimeters to re-order? If not the perimeters will be processed outside in.
-                        std::vector<PerimeterGeneratorArachneExtrusion> inner_outer_extrusions; // temporary array to hold extrusions for reordering
-                        inner_outer_extrusions.resize(max_internal - position + 1); // reserve array containing the number of perimeters before a new island. Variables are array indexes hence need to add +1 to convert to position allocations
-                        // printf("Allocated array size %d, max_internal index %d, start position index %d \n",max_internal-position+1,max_internal,position);
-                        
-                        for (arr_j = max_internal; arr_j >=position; --arr_j){ // go inside out towards the external perimeter (perimeters in reverse order) and store all internal perimeters until the first one identified with inset index 2
-                            if(arr_j >= second_internal){
-                                //printf("Inside out loop: Mapped perimeter index %d to array position %d\n", arr_j, max_internal-arr_j);
-                                inner_outer_extrusions[max_internal-arr_j] = reordered_extrusions[arr_j];
-                                current_perimeter++; 
+                    // Now start the sandwich mode wall re-ordering using the reordered_extrusions as the basis
+                    // scan to find the external perimeter, first internal, second internal and last perimeter in the island.
+                    // We then advance the position index to move to the second island and continue until there are no more
+                    // perimeters left.
+                    while (position < reordered_extrusions.size()) {
+                        outer = first_internal = second_internal = current_perimeter = -1; // initialise all index values to -1
+                        max_internal = reordered_extrusions.size()-1; // initialise the maximum internal perimeter to the last perimeter on the extrusion list
+                        // run through the walls to get the index values that need re-ordering until the first one for each
+                        // is found. Start at "position" index to enable the for loop to iterate for multiple external
+                        // perimeters in a single island
+                        // printf("Reorder Loop. Position %d, extrusion list size: %d, Outer index %d, inner index %d, second inner index %d\n", position, reordered_extrusions.size(),outer,first_internal,second_internal);
+                        for (arr_i = position; arr_i < reordered_extrusions.size(); ++arr_i) {
+                            // printf("Perimeter: extrusion inset index %d, ordered extrusions array position %d\n",reordered_extrusions[arr_i].extrusion->inset_idx, arr_i);
+                            switch (reordered_extrusions[arr_i].extrusion->inset_idx) {
+                                case 0: // external perimeter
+                                    if (outer == -1)
+                                        outer = arr_i;
+                                    break;
+                                case 1: // first internal wall
+                                    if (first_internal==-1 && arr_i>outer && outer!=-1){
+                                        first_internal = arr_i;
+                                    }
+                                    break;
+                                case 2: // second internal wall
+                                    if (second_internal == -1 && arr_i > first_internal && outer!=-1){
+                                        second_internal = arr_i;
+                                    }
+                                    break;
+                            }
+                            if(outer >-1 && first_internal>-1 && reordered_extrusions[arr_i].extrusion->inset_idx == 0){  // found a new external perimeter after we've found at least a first internal perimeter to re-order.
+                                                                                                                          // This means we entered a new island.
+                                arr_i=arr_i-1; //step back one perimeter
+                                max_internal = arr_i; // new maximum internal perimeter is now this as we have found a new external perimeter, hence a new island.
+                                break; // exit the for loop
                             }
                         }
+                    
+                        // printf("Layer ID %d, Outer index %d, inner index %d, second inner index %d, maximum internal perimeter %d \n",layer_id,outer,first_internal,second_internal, max_internal);
+                        if (outer > -1 && first_internal > -1 && second_internal > -1) { // found all three perimeters to re-order? If not the perimeters will be processed outside in.
+                            std::vector<PerimeterGeneratorArachneExtrusion> inner_outer_extrusions; // temporary array to hold extrusions for reordering
+                            inner_outer_extrusions.resize(max_internal - position + 1); // reserve array containing the number of perimeters before a new island. Variables are array indexes hence need to add +1 to convert to position allocations
+                            // printf("Allocated array size %d, max_internal index %d, start position index %d \n",max_internal-position+1,max_internal,position);
                         
-                        for (arr_j = position; arr_j < second_internal; ++arr_j){ // go outside in and map the remaining perimeters (external and first internal wall(s)) using the outside in wall order
-                            // printf("Outside in loop: Mapped perimeter index %d to array position %d\n", arr_j, current_perimeter+1);
-                            inner_outer_extrusions[++current_perimeter] = reordered_extrusions[arr_j];
+                            for (arr_j = max_internal; arr_j >=position; --arr_j){ // go inside out towards the external perimeter (perimeters in reverse order) and store all internal perimeters until the first one identified with inset index 2
+                                if(arr_j >= second_internal){
+                                    //printf("Inside out loop: Mapped perimeter index %d to array position %d\n", arr_j, max_internal-arr_j);
+                                    inner_outer_extrusions[max_internal-arr_j] = reordered_extrusions[arr_j];
+                                    current_perimeter++; 
+                                }
+                            }
+                        
+                            for (arr_j = position; arr_j < second_internal; ++arr_j){ // go outside in and map the remaining perimeters (external and first internal wall(s)) using the outside in wall order
+                                // printf("Outside in loop: Mapped perimeter index %d to array position %d\n", arr_j, current_perimeter+1);
+                                inner_outer_extrusions[++current_perimeter] = reordered_extrusions[arr_j];
+                            }
+                        
+                            for(arr_j = position; arr_j <= max_internal; ++arr_j) // replace perimeter array with the new re-ordered array
+                                ordered_extrusions[arr_j] = inner_outer_extrusions[arr_j-position];
                         }
-                        
-                        for(arr_j = position; arr_j <= max_internal; ++arr_j) // replace perimeter array with the new re-ordered array
-                            ordered_extrusions[arr_j] = inner_outer_extrusions[arr_j-position];
+                        // go to the next perimeter from the current position to continue scanning for external walls in the same island
+                        position = arr_i + 1;
                     }
-                    // go to the next perimeter from the current position to continue scanning for external walls in the same island
-                    position = arr_i + 1;
                 }
             }
-        }
         
-        bool steep_overhang_contour = false;
-        bool steep_overhang_hole    = false;
-        if (!config->overhang_reverse) {
-            // Skip steep overhang detection no reverse is specified
-            steep_overhang_contour = true;
-            steep_overhang_hole    = true;
-        }
-        if (ExtrusionEntityCollection extrusion_coll = traverse_extrusions(*this, ordered_extrusions, steep_overhang_contour, steep_overhang_hole); !extrusion_coll.empty()) {
-            if (config->overhang_reverse) {
-                reorient_perimeters(extrusion_coll, steep_overhang_contour, steep_overhang_hole,
-                                    this->config->overhang_reverse_internal_only);
+            bool steep_overhang_contour = false;
+            bool steep_overhang_hole    = false;
+            if (!config->overhang_reverse) {
+                // Skip steep overhang detection no reverse is specified
+                steep_overhang_contour = true;
+                steep_overhang_hole    = true;
+            }
+            if (ExtrusionEntityCollection extrusion_coll = traverse_extrusions(*this, ordered_extrusions, steep_overhang_contour, steep_overhang_hole); !extrusion_coll.empty()) {
+                if (config->overhang_reverse) {
+                    reorient_perimeters(extrusion_coll, steep_overhang_contour, steep_overhang_hole,
+                                        this->config->overhang_reverse_internal_only);
+                }
+                defer_unsupported_loops(*this, extrusion_coll);
+                result.loops     = std::move(extrusion_coll);
+                result.has_loops = true;
             }
-            defer_unsupported_loops(*this, extrusion_coll);
-            this->loops->append(extrusion_coll);
-        }
 
-        const coord_t spacing = (perimeters.size() == 1) ? ext_perimeter_spacing2 : perimeter_spacing;
+            const coord_t spacing = (perimeters.size() == 1) ? ext_perimeter_spacing2 : perimeter_spacing;
 
-        if (offset_ex(infill_contour, -float(spacing / 2.)).empty())
-            infill_contour.clear(); // Infill region is too small, so let's filter it out.
+            if (offset_ex(infill_contour, -float(spacing / 2.)).empty())
+                infill_contour.clear(); // Infill region is too small, so let's filter it out.
 
-        // create one more offset to be used as boundary for fill
-        // we offset by half the perimeter spacing (to get to the actual infill boundary)
-        // and then we offset back and forth by half the infill spacing to only consider the
-        // non-collapsing regions
-        coord_t inset =
-            (loop_number < 0) ? 0 :
-            (loop_number == 0) ?
-            // one loop
-            ext_perimeter_spacing :
-            // two or more loops?
-            perimeter_spacing;
-        coord_t top_inset = inset;
+            // create one more offset to be used as boundary for fill
+            // we offset by half the perimeter spacing (to get to the actual infill boundary)
+            // and then we offset back and forth by half the infill spacing to only consider the
+            // non-collapsing regions
+            coord_t inset =
+                (loop_number < 0) ? 0 :
+                (loop_number == 0) ?
+                // one loop
+                ext_perimeter_spacing :
+                // two or more loops?
+                perimeter_spacing;
+            coord_t top_inset = inset;
         
-        top_inset = coord_t(scale_(this->config->top_bottom_infill_wall_overlap.get_abs_value(unscale<double>(inset))));
-        if(is_topmost_layer || is_bottom_layer)
-            inset = coord_t(scale_(this->config->top_bottom_infill_wall_overlap.get_abs_value(unscale<double>(inset))));
-        else
-            inset = coord_t(scale_(this->config->infill_wall_overlap.get_abs_value(unscale<double>(inset))));
+            top_inset = coord_t(scale_(this->config->top_bottom_infill_wall_overlap.get_abs_value(unscale<double>(inset))));
+            if(is_topmost_layer || is_bottom_layer)
+                inset = coord_t(scale_(this->config->top_bottom_infill_wall_overlap.get_abs_value(unscale<double>(inset))));
+            else
+                inset = coord_t(scale_(this->config->infill_wall_overlap.get_abs_value(unscale<double>(inset))));
         
-        // simplify infill contours according to resolution
-        Polygons pp;
-        for (ExPolygon& ex : infill_contour)
-            ex.simplify_p(m_scaled_resolution, &pp);
-        ExPolygons not_filled_exp = union_ex(pp);
-        // collapse too narrow infill areas
-        const auto    min_perimeter_infill_spacing = coord_t(solid_infill_spacing * (1. - INSET_OVERLAP_TOLERANCE));
+            // simplify infill contours according to resolution
+            Polygons pp;
+            for (ExPolygon& ex : infill_contour)
+                ex.simplify_p(m_scaled_resolution, &pp);
+            ExPolygons not_filled_exp = union_ex(pp);
+            // collapse too narrow infill areas
+            const auto    min_perimeter_infill_spacing = coord_t(solid_infill_spacing * (1. - INSET_OVERLAP_TOLERANCE));
 
-        ExPolygons infill_exp = offset2_ex(
-            not_filled_exp,
-            float(-min_perimeter_infill_spacing / 2.),
-            float(inset + min_perimeter_infill_spacing / 2.));
-        // append infill areas to fill_surfaces
-        if (!top_expolygons.empty()) {
-            infill_exp = union_ex(infill_exp, offset_ex(top_expolygons, double(top_inset)));
-        }
-        this->fill_surfaces->append(infill_exp, stInternal);
-
-        apply_extra_perimeters(infill_exp);
-
-        // BBS: get the no-overlap infill expolygons
-        {
-            ExPolygons polyWithoutOverlap;
-            polyWithoutOverlap = offset2_ex(
+            ExPolygons infill_exp = offset2_ex(
                 not_filled_exp,
                 float(-min_perimeter_infill_spacing / 2.),
-                float(+min_perimeter_infill_spacing / 2.));
-            if (!top_expolygons.empty())
-                polyWithoutOverlap = union_ex(polyWithoutOverlap, top_expolygons);
-            this->fill_no_overlap->insert(this->fill_no_overlap->end(), polyWithoutOverlap.begin(), polyWithoutOverlap.end());
-        }
+                float(inset + min_perimeter_infill_spacing / 2.));
+            // append infill areas to fill_surfaces
+            if (!top_expolygons.empty()) {
+                infill_exp = union_ex(infill_exp, offset_ex(top_expolygons, double(top_inset)));
+            }
+            result.infill = std::move(infill_exp);
+
+            // BBS: get the no-overlap infill expolygons
+            {
+                ExPolygons polyWithoutOverlap;
+                polyWithoutOverlap = offset2_ex(
+                    not_filled_exp,
+                    float(-min_perimeter_infill_spacing / 2.),
+                    float(+min_perimeter_infill_spacing / 2.));
+                if (!top_expolygons.empty())
+                    polyWithoutOverlap = union_ex(polyWithoutOverlap, top_expolygons);
+                result.no_overlap = std::move(polyWithoutOverlap);
+            }
+      }
+    });
+    for (ArachneSurfaceResult &result : results) {
+        if (result.has_loops)
+            this->loops->append(result.loops);
+        this->fill_surfaces->append(result.infill, stInternal);
+        apply_extra_perimeters(result.infill);
+        this->fill_no_overlap->insert(this->fill_no_overlap->end(), result.no_overlap.begin(), result.no_overlap.end());
     }
 }
 

src/libslic3r/Polygon.hpp

@@ -27,7 +27,7 @@ public:
     explicit Polygon(const Points &points) : MultiPoint(points) {}
 	Polygon(std::initializer_list<Point> points) : MultiPoint(points) {}
     Polygon(const Polygon &other) : MultiPoint(other.points) {}
-    Polygon(Polygon &&other) : MultiPoint(std::move(other.points)) {}
+    Polygon(Polygon &&other) noexcept : MultiPoint(std::move(other.points)) {}
 	static Polygon new_scale(const std::vector<Vec2d> &points) { 
         Polygon pgn;
         pgn.points.reserve(points.size());
@@ -36,7 +36,7 @@ public:
 		return pgn;
 	}
     Polygon& operator=(const Polygon &other) { points = other.points; return *this; }
-    Polygon& operator=(Polygon &&other) { points = std::move(other.points); return *this; }
+    Polygon& operator=(Polygon &&other) noexcept { points = std::move(other.points); return *this; }
 
     Point& operator[](Points::size_type idx) { return this->points[idx]; }
     const Point& operator[](Points::size_type idx) const { return this->points[idx]; }

src/libslic3r/Polyline.hpp

@@ -20,7 +20,7 @@ class Polyline : public MultiPoint {
 public:
     Polyline() {};
     Polyline(const Polyline& other) : MultiPoint(other.points), fitting_result(other.fitting_result) {}
-    Polyline(Polyline &&other) : MultiPoint(std::move(other.points)), fitting_result(std::move(other.fitting_result))  {}
+    Polyline(Polyline &&other) noexcept : MultiPoint(std::move(other.points)), fitting_result(std::move(other.fitting_result))  {}
     Polyline(std::initializer_list<Point> list) : MultiPoint(list) { 
         fitting_result.clear();
     }
@@ -41,7 +41,7 @@ public:
         fitting_result = other.fitting_result;
         return *this;
     }
-    Polyline& operator=(Polyline&& other) {
+    Polyline& operator=(Polyline&& other) noexcept {
         points = std::move(other.points);
         fitting_result = std::move(other.fitting_result);
         return *this;

src/libslic3r/Preset.cpp

@@ -5,8 +5,6 @@
 #include "Preset.hpp"
 #include "PresetBundle.hpp"
 #include "AppConfig.hpp"
-#include "LocalesUtils.hpp"
-#include "ParallelResolve.hpp"
 
 #ifdef _MSC_VER
     #define WIN32_LEAN_AND_MEAN
@@ -51,9 +49,6 @@
 #include "libslic3r.h"
 #include "LifecycleEvents.hpp"
 #include "Utils.hpp"
-#include "InstanceLock.hpp"
-
-#include <sstream>
 #include "Time.hpp"
 #include "PlaceholderParser.hpp"
 #include "libslic3r/GCode/Thumbnails.hpp"
@@ -110,32 +105,6 @@ std::string get_preset_canonical_name(const std::string &preset_bare_name, const
     }
 }
 
-std::string user_presets_lock_path(bool read_only)
-{
-    return read_only || data_dir().empty() ? std::string() : (fs::path(data_dir()) / (PRESET_USER_DIR ".lock")).string();
-}
-
-// Removes a preset file the scan could not load, and its .info, under the lock.
-// The scan passes read_only when it could not take the lock, since the file may
-// then be another instance's fresh write that it merely raced.
-static void remove_preset_files(const std::string &preset_file, bool read_only)
-{
-    if (read_only)
-        return;
-    InstanceLock instance_lock(user_presets_lock_path());
-    // A symlink whose target is missing stays, since the target may come back; one
-    // that cannot even be followed is removed like any other unreadable file.
-    auto remove = [](const fs::path &file) {
-        boost::system::error_code ec;
-        if (fs::status(file, ec).type() != fs::file_not_found)
-            fs::remove(file, ec);
-    };
-    fs::path file_path(preset_file);
-    remove(file_path);
-    file_path.replace_extension(".info");
-    remove(file_path);
-}
-
 std::string get_preset_bare_name(const std::string &canonical_name)
 {
     const auto pos = canonical_name.find_last_of('/');
@@ -537,11 +506,10 @@ void Preset::normalize(DynamicPrintConfig &config)
     handle_legacy_sla(config);
 }
 
-std::string Preset::remove_invalid_keys(DynamicPrintConfig &config, const DynamicPrintConfig &default_config,
-                                        const DynamicPrintConfig *added)
+std::string Preset::remove_invalid_keys(DynamicPrintConfig &config, const DynamicPrintConfig &default_config)
 {
     std::string incorrect_keys;
-    for (const std::string &key : (added != nullptr ? *added : config).keys())
+    for (const std::string &key : config.keys())
         if (! default_config.has(key)) {
             if (incorrect_keys.empty())
                 incorrect_keys = key;
@@ -653,6 +621,7 @@ void Preset::load_info(const std::string& file)
             }
             else if (v.first.compare("base_id") == 0) {
                 this->base_id = v.second.get_value<std::string>();
+                BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " load info from: " << file << " and base_id: " << this->base_id;
                 if (this->base_id.compare("null") == 0)
                     this->base_id.clear();
             }
@@ -678,20 +647,18 @@ void Preset::save_info(std::string file)
         file = idx_file.string();
     }
 
+    boost::nowide::ofstream c;
+    c.open(file, std::ios::out | std::ios::trunc);
     std::string sync_info_to_save;
     //BBS: hold is used for stop requesting to server this time
     if (this->sync_info.compare("hold") != 0)
         sync_info_to_save = this->sync_info;
-    std::ostringstream c;
     c << "sync_info" << " = " << sync_info_to_save << std::endl;
     c << "user_id" << " = " << this->user_id << std::endl;
     c << "setting_id" << " = " << this->setting_id << std::endl;
     c << "base_id" << " = " << this->base_id << std::endl;
     c << "updated_time" << " = " << std::to_string(this->updated_time) << std::endl;
-
-    InstanceLock instance_lock(user_presets_lock_path());
-    if (const std::error_code ec = write_file_atomically(file, c.str()))
-        BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << ": failed to save " << file << ": " << ec.message();
+    c.close();
 }
 
 void Preset::remove_files(bool cloud_already_deleted)
@@ -700,7 +667,6 @@ void Preset::remove_files(bool cloud_already_deleted)
     if (this->is_project_embedded) {
         return;
     }
-    InstanceLock instance_lock(user_presets_lock_path());
     // Erase the preset file.
     boost::nowide::remove(this->file.c_str());
     fs::path idx_path(this->file);
@@ -718,11 +684,11 @@ void Preset::remove_files(bool cloud_already_deleted)
 }
 
 //BBS: add logic for only difference save
-bool Preset::save(DynamicPrintConfig* parent_config)
+void Preset::save(DynamicPrintConfig* parent_config)
 {
     //BBS: add project embedded preset logic
     if (this->is_project_embedded)
-        return true;
+        return;
     //BBS: change to json format
     //this->config.save(this->file);
     std::string from_str;
@@ -737,16 +703,12 @@ bool Preset::save(DynamicPrintConfig* parent_config)
     else
         from_str = std::string("Default");
 
+    boost::filesystem::create_directories(fs::path(this->file).parent_path());
     const std::string bare_name = get_preset_bare_name(this->name);
 
-    // What gets written: the diff against the parent, the config plus its
-    // filament id, or the config as is. Built before the lock is taken so the
-    // exclusive window covers only the file writes.
-    DynamicPrintConfig        temp_config;
-    const DynamicPrintConfig *to_save = &this->config;
-
     //BBS: only save difference if it has parent
     if (parent_config) {
+        DynamicPrintConfig temp_config;
         std::vector<std::string> dirty_options = config.diff(*parent_config);
 
         std::string extruder_id_name, extruder_variant_name;
@@ -782,22 +744,13 @@ bool Preset::save(DynamicPrintConfig* parent_config)
                     opt_dst->set(opt_src);
             }
         }
-        to_save = &temp_config;
+        temp_config.save_to_json(this->file, bare_name, from_str, this->version.to_string());
     } else if (!filament_id.empty() && inherits().empty()) {
-        temp_config = config;
+        DynamicPrintConfig temp_config = config;
         temp_config.set_key_value(BBL_JSON_KEY_FILAMENT_ID, new ConfigOptionString(filament_id));
-        to_save = &temp_config;
-    }
-
-    std::ostringstream json;
-    to_save->save_to_json(json, bare_name, from_str, this->version.to_string());
-
-    InstanceLock instance_lock(user_presets_lock_path());
-    boost::filesystem::create_directories(fs::path(this->file).parent_path());
-    if (const std::error_code ec = write_file_atomically(this->file, json.str())) {
-        // No .info either: one without its preset reads as a cloud deletion request.
-        BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << ": failed to save " << this->file << ": " << ec.message();
-        return false;
+        temp_config.save_to_json(this->file, bare_name, from_str, this->version.to_string());
+    } else {
+        this->config.save_to_json(this->file, bare_name, from_str, this->version.to_string());
     }
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " save config for: " << this->name << " and filament_id: " << filament_id << " and base_id: " << this->base_id;
 
@@ -807,7 +760,6 @@ bool Preset::save(DynamicPrintConfig* parent_config)
         idx_file.replace_extension(".info");
         this->save_info(idx_file.string());
     }
-    return true;
 }
 
 void Preset::reload(Preset const &parent)
@@ -819,7 +771,6 @@ void Preset::reload(Preset const &parent)
     std::string                        reason;
     ForwardCompatibilitySubstitutionRule substitution_rule    = ForwardCompatibilitySubstitutionRule::Disable;
     try {
-        InstanceLock instance_lock(user_presets_lock_path());
         ConfigSubstitutions                config_substitutions = config.load_from_json(file, substitution_rule, key_values, reason);
         this->config = parent.config;
         this->config.apply(std::move(config));
@@ -1718,185 +1669,6 @@ std::string PresetCollection::canonical_preset_name(const std::string &name, con
     return get_preset_canonical_name(parsed.bare, origin);
 }
 
-PresetCollection::PresetFilesOnDisk PresetCollection::PresetFilesOnDisk::read(const boost::filesystem::path &file)
-{
-    auto read_if_present = [](const fs::path &path) -> std::optional<std::string> {
-        std::string bytes;
-        try {
-            load_string_file(path, bytes);
-        } catch (const std::exception &) {
-            return std::nullopt;
-        }
-        return bytes;
-    };
-    fs::path info_path(file);
-    info_path.replace_extension(".info");
-    return { read_if_present(file), read_if_present(info_path) };
-}
-
-PresetCollection::UserPresetLoad PresetCollection::resolve_user_preset(
-    const boost::filesystem::path &file, const std::string &canonical_name,
-    const PresetOrigin &load_origin, ForwardCompatibilitySubstitutionRule substitution_rule,
-    const std::string &extruder_id_name, const std::string &extruder_variant_name,
-    std::set<std::string> *key_set1, std::set<std::string> *key_set2) const
-{
-    UserPresetLoad out;
-    out.preset = Preset(m_type, canonical_name, false);
-    Preset &preset = out.preset;
-    preset.bundle_id = load_origin.bundle_id;
-    preset.file = file.string();
-    // Before either file is parsed, so a save that lands during the parse still shows
-    // up as a difference when commit compares.
-    out.on_disk = PresetFilesOnDisk::read(file);
-    // Load the preset file, apply preset values on top of defaults.
-    try {
-        fs::path idx_path(preset.file);
-        idx_path.replace_extension(".info");
-        if (fs::exists(idx_path)) {
-            out.info_file = idx_path.string();
-            preset.load_info(out.info_file);
-        }
-        DynamicPrintConfig config;
-        //BBS: change to json format
-        //ConfigSubstitutions config_substitutions = config.load_from_ini(preset.file, substitution_rule);
-        std::map<std::string, std::string> key_values;
-        std::string reason;
-        ConfigSubstitutions config_substitutions = config.load_from_json(preset.file, substitution_rule, key_values, reason);
-        if (! config_substitutions.empty())
-            out.substitutions.push_back({ preset.name, m_type, PresetConfigSubstitutions::Source::UserFile, preset.file, std::move(config_substitutions) });
-        if (!reason.empty()) {
-            out.discard_file = true;
-            out.errors.push_back((boost::format("parse config %1% failed") % preset.file).str());
-            return out;
-        }
-
-        std::string version_str = key_values[BBL_JSON_KEY_VERSION];
-        boost::optional<Semver> version = Semver::parse(version_str);
-        if (!version) return out;
-        preset.version = *version;
-
-        if (key_values.find(BBL_JSON_KEY_FILAMENT_ID) != key_values.end())
-            preset.filament_id = key_values[BBL_JSON_KEY_FILAMENT_ID];
-        if (key_values.find(BBL_JSON_KEY_DESCRIPTION) != key_values.end())
-            preset.description = key_values[BBL_JSON_KEY_DESCRIPTION];
-        if (key_values.find(BBL_JSON_KEY_INSTANTIATION) != key_values.end())
-            preset.is_visible = key_values[BBL_JSON_KEY_INSTANTIATION] != "false";
-
-        //Orca: find and use the inherit config as the base
-        const Preset* inherit_preset = nullptr;
-        ConfigOption* inherits_config = config.option(BBL_JSON_KEY_INHERITS);
-
-        // check inherits_config
-        if (inherits_config) {
-            ConfigOptionString * option_str = dynamic_cast<ConfigOptionString *> (inherits_config);
-            std::string inherits_value = option_str->value;
-            // Orca: try to find if the parent preset has been renamed
-            inherit_preset = this->find_preset2(inherits_value);
-            Preset::normalize_inherits(config, inherit_preset);
-        }
-        const Preset& default_preset = this->default_preset_for(config);
-        if (inherit_preset) {
-            preset.config = inherit_preset->config;
-            preset.filament_id = inherit_preset->filament_id;
-            extend_default_config_length(config, false, {});
-            preset.config.update_diff_values_to_child_config(config, extruder_id_name, extruder_variant_name, *key_set1, *key_set2);
-        }
-        else {
-            auto inherits_config2 = dynamic_cast<ConfigOptionString *>(inherits_config);
-            if ((inherits_config2 && !inherits_config2->value.empty())) {
-                out.errors.push_back((boost::format("can not find parent %1% for config %2%!") % inherits_config2->value % preset.file).str());
-                return out;
-            }
-            // We support custom root preset now
-            // Find a default preset for the config. The PrintPresetCollection provides different default preset based on the "printer_technology" field.
-            preset.config = default_preset.config;
-            preset.config.apply(std::move(config));
-            extend_default_config_length(preset.config, true, default_preset.config);
-        }
-
-        Preset::normalize(preset.config);
-        // Report configuration fields, which are misplaced into a wrong group.
-        std::string incorrect_keys = Preset::remove_invalid_keys(preset.config, default_preset.config);
-        if (!incorrect_keys.empty())
-            out.errors.push_back("Error in a preset file: The preset \"" + preset.file +
-                                 "\" contains the following incorrect keys: " + incorrect_keys + ", which were removed");
-
-        if (preset.type == Preset::TYPE_FILAMENT && preset.is_user() && preset.inherits().empty()) {
-            auto compatible_printers = dynamic_cast<ConfigOptionStrings *>(preset.config.option("compatible_printers", true));
-            if (compatible_printers && compatible_printers->values.empty()) {
-                size_t at_pos = canonical_name.find('@');
-                if (at_pos != std::string::npos && at_pos + 1 < canonical_name.length()) {
-                    compatible_printers->values.push_back(canonical_name.substr(at_pos + 1));
-                    out.save_compatible_printers = true;
-                }
-            }
-        }
-
-        preset.loaded = true;
-        out.complete = true;
-    } catch (const std::ifstream::failure &err) {
-        out.discard_file = true;
-        out.errors.push_back((boost::format("The user-config cannot be loaded: %1%. Reason: %2%") % preset.file % err.what()).str());
-        //throw Slic3r::RuntimeError(std::string("The selected preset cannot be loaded: ") + preset.file + "\n\tReason: " + err.what());
-    } catch (const std::runtime_error &err) {
-        out.discard_file = true;
-        out.errors.push_back((boost::format("Failed loading the user-config file: %1%. Reason: %2%") % preset.file % err.what()).str());
-        //throw Slic3r::RuntimeError(std::string("Failed loading the preset file: ") + preset.file + "\n\tReason: " + err.what());
-    }
-    out.install = true;
-    return out;
-}
-
-void PresetCollection::commit_user_preset(UserPresetLoad &&loaded, std::deque<Preset> &presets_loaded,
-                                          PresetsConfigSubstitutions &substitutions,
-                                          const std::function<void(Preset&)> &preset_loaded_fn,
-                                          bool read_only)
-{
-    Preset &preset = loaded.preset;
-    if (! loaded.info_file.empty())
-        BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " load info from: " << loaded.info_file << " and base_id: " << preset.base_id;
-    append(substitutions, std::move(loaded.substitutions));
-    for (const std::string &error : loaded.errors) {
-        ++m_errors;
-        BOOST_LOG_TRIVIAL(error) << error;
-    }
-    if (loaded.discard_file)
-        remove_preset_files(loaded.preset.file, read_only);
-    if (!loaded.install)
-        return;
-
-    if (loaded.complete) {
-        if (loaded.save_compatible_printers) {
-            // A filesystem error from the rewrite is counted, and the preset still loads.
-            try {
-                if (read_only)
-                    BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " added compatible_printers for preset: " << preset.name << " (not written back)";
-                else if (preset.save(nullptr))
-                    BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " added compatible_printers for preset: " << preset.name;
-                else
-                    ++m_errors; // save() logged why
-            } catch (const std::runtime_error &err) {
-                ++m_errors;
-                BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << " can not write compatible_printers back to " << preset.file << ": " << err.what();
-            }
-        }
-        //BBS: add some workaround for previous incorrect settings
-        if ((!preset.setting_id.empty())&&(preset.setting_id == preset.base_id))
-            preset.setting_id.clear();
-        BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " load preset: " << preset.name << " and filament_id: " << preset.filament_id << " and base_id: " << preset.base_id;
-        //BBS: add config related logs
-        BOOST_LOG_TRIVIAL(debug) << __FUNCTION__ << boost::format(", preset type %1%, name %2%, path %3%, is_system %4%, is_default %5% is_visible %6%")%Preset::get_type_string(m_type) %preset.name %preset.file %preset.is_system %preset.is_default %preset.is_visible;
-        // add alias for custom filament preset
-        set_custom_preset_alias(preset);
-    }
-
-    if (preset_loaded_fn != nullptr)
-        preset_loaded_fn(preset);
-
-    BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << __LINE__ << " load config successful and preset name is:" << preset.name;
-    presets_loaded.emplace_back(std::move(preset));
-}
-
 // Load all presets found in dir_path.
 // Throws an exception on error.
 void PresetCollection::load_presets(
@@ -1934,8 +1706,6 @@ void PresetCollection::load_presets(
     std::set<std::string> *key_set1 = nullptr, *key_set2 = nullptr;
     Preset::get_extruder_names_and_keysets(m_type, extruder_id_name, extruder_variant_name, &key_set1, &key_set2);
 
-    struct UserPresetFile { fs::path path; std::string canonical_name; };
-    std::vector<UserPresetFile> files;
     //BBS: change to json format
     for (auto &dir_entry : boost::filesystem::directory_iterator(dir))
     {
@@ -1951,47 +1721,149 @@ void PresetCollection::load_presets(
                 BOOST_LOG_TRIVIAL(warning) << "Preset already present, not loading: " << canonical_name;
                 continue;
             }
-            files.push_back({ dir_entry.path(), std::move(canonical_name) });
-        }
-    }
-
-    resolve_then_commit<CNumericLocalesSetter>(files.size(),
-        [&](size_t i) {
-            return this->resolve_user_preset(files[i].path, files[i].canonical_name, resolved_origin, substitution_rule,
-                                             extruder_id_name, extruder_variant_name, key_set1, key_set2);
-        },
-        [&](size_t i, UserPresetLoad &&loaded) {
-            // Resolve read the files without the lock, so another instance may have saved
-            // over them since. A file that changed is resolved again under the lock before
-            // commit removes or rewrites it, which also keeps its .json and .info from two
-            // different saves apart. Without the lock nothing is checked, so commit leaves
-            // the files alone.
-            const std::string lock_path = user_presets_lock_path(read_only);
-            InstanceLock      instance_lock(lock_path);
-            if (instance_lock.locked()) {
-                const PresetFilesOnDisk   on_disk = PresetFilesOnDisk::read(files[i].path);
-                boost::system::error_code ec;
-                // The link itself, and a stat error counts as present, so a file that is
-                // there but cannot be read is still counted and removed by commit.
-                if (! on_disk.json && fs::symlink_status(files[i].path, ec).type() == fs::file_not_found)
-                    return; // removed by another instance since it was read
-                if (! (on_disk == loaded.on_disk)) {
-                    CNumericLocalesSetter locales_setter;
-                    loaded = this->resolve_user_preset(files[i].path, files[i].canonical_name, resolved_origin, substitution_rule,
-                                                       extruder_id_name, extruder_variant_name, key_set1, key_set2);
-                }
-            }
-            const bool leave_files = read_only || (! lock_path.empty() && ! instance_lock.locked());
-            // Committing can remove an unreadable preset's file, and a filesystem error
-            // there is reported without stopping the rest of the directory.
             try {
-                this->commit_user_preset(std::move(loaded), presets_loaded, substitutions, preset_loaded_fn, leave_files);
+                Preset preset(m_type, canonical_name, false);
+                preset.bundle_id = resolved_origin.bundle_id;
+                preset.file = dir_entry.path().string();
+                // Load the preset file, apply preset values on top of defaults.
+                try {
+                    fs::path idx_path(preset.file);
+                    idx_path.replace_extension(".info");
+                    if (fs::exists(idx_path)) {
+                        preset.load_info(idx_path.string());
+                    }
+                    DynamicPrintConfig config;
+                    //BBS: change to json format
+                    //ConfigSubstitutions config_substitutions = config.load_from_ini(preset.file, substitution_rule);
+                    std::map<std::string, std::string> key_values;
+                    std::string reason;
+                    ConfigSubstitutions config_substitutions = config.load_from_json(preset.file, substitution_rule, key_values, reason);
+                    if (! config_substitutions.empty())
+                        substitutions.push_back({ preset.name, m_type, PresetConfigSubstitutions::Source::UserFile, preset.file, std::move(config_substitutions) });
+                    if (!reason.empty()) {
+                        fs::path file_path(preset.file);
+                        if (!read_only && fs::exists(file_path))
+                            fs::remove(file_path);
+                        file_path.replace_extension(".info");
+                        if (!read_only && fs::exists(file_path))
+                            fs::remove(file_path);
+                        BOOST_LOG_TRIVIAL(error) << boost::format("parse config %1% failed")%preset.file;
+                        ++m_errors;
+                        continue;
+                    }
+
+                    std::string version_str = key_values[BBL_JSON_KEY_VERSION];
+                    boost::optional<Semver> version = Semver::parse(version_str);
+                    if (!version) continue;
+                    preset.version = *version;
+
+                    if (key_values.find(BBL_JSON_KEY_FILAMENT_ID) != key_values.end())
+                        preset.filament_id = key_values[BBL_JSON_KEY_FILAMENT_ID];
+                    if (key_values.find(BBL_JSON_KEY_DESCRIPTION) != key_values.end())
+                        preset.description = key_values[BBL_JSON_KEY_DESCRIPTION];
+                    if (key_values.find(BBL_JSON_KEY_INSTANTIATION) != key_values.end())
+                        preset.is_visible = key_values[BBL_JSON_KEY_INSTANTIATION] != "false";
+
+                    //Orca: find and use the inherit config as the base
+                    Preset* inherit_preset = nullptr;
+                    ConfigOption* inherits_config = config.option(BBL_JSON_KEY_INHERITS);
+
+                    // check inherits_config
+                    if (inherits_config) {
+                        ConfigOptionString * option_str = dynamic_cast<ConfigOptionString *> (inherits_config);
+                        std::string inherits_value = option_str->value;
+                        // Orca: try to find if the parent preset has been renamed
+                        inherit_preset = this->find_preset2(inherits_value);
+                        Preset::normalize_inherits(config, inherit_preset);
+                    } else {
+                        ;
+                    }
+                    const Preset& default_preset = this->default_preset_for(config);
+                    if (inherit_preset) {
+                        preset.config = inherit_preset->config;
+                        preset.filament_id = inherit_preset->filament_id;
+                        extend_default_config_length(config, false, {});
+                        preset.config.update_diff_values_to_child_config(config, extruder_id_name, extruder_variant_name, *key_set1, *key_set2);
+                    }
+                    else {
+                        auto inherits_config2 = dynamic_cast<ConfigOptionString *>(inherits_config);
+                        if ((inherits_config2 && !inherits_config2->value.empty())) {
+                            BOOST_LOG_TRIVIAL(error) << boost::format("can not find parent %1% for config %2%!")%inherits_config2->value %preset.file;
+                            ++m_errors;
+                            continue;
+                        }
+                        // We support custom root preset now
+                        // Find a default preset for the config. The PrintPresetCollection provides different default preset based on the "printer_technology" field.
+                        preset.config = default_preset.config;
+                        preset.config.apply(std::move(config));
+                        extend_default_config_length(preset.config, true, default_preset.config);
+                    }
+                    BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " load preset: " << name << " and filament_id: " << preset.filament_id << " and base_id: " << preset.base_id;
+
+                    Preset::normalize(preset.config);
+                    // Report configuration fields, which are misplaced into a wrong group.
+                    std::string incorrect_keys = Preset::remove_invalid_keys(preset.config, default_preset.config);
+                    if (!incorrect_keys.empty()) {
+                        ++m_errors;
+                        BOOST_LOG_TRIVIAL(error)
+                            << "Error in a preset file: The preset \"" << preset.file
+                            << "\" contains the following incorrect keys: " << incorrect_keys << ", which were removed";
+                    }
+
+                    if (preset.type == Preset::TYPE_FILAMENT && preset.is_user() && preset.inherits().empty()) {
+                        auto compatible_printers = dynamic_cast<ConfigOptionStrings *>(preset.config.option("compatible_printers", true));
+                        if (compatible_printers && compatible_printers->values.empty()) {
+                            size_t at_pos = name.find('@');
+                            if (at_pos != std::string::npos && at_pos + 1 < name.length()) {
+                                compatible_printers->values.push_back(name.substr(at_pos + 1));
+                                if (!read_only)
+                                    preset.save(nullptr);
+                                BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " added compatible_printers for preset: " << name;
+                            }
+                        }
+                    }
+
+                    preset.loaded = true;
+                    //BBS: add some workaround for previous incorrect settings
+                    if ((!preset.setting_id.empty())&&(preset.setting_id == preset.base_id))
+                        preset.setting_id.clear();
+                    //BBS: add config related logs
+                    BOOST_LOG_TRIVIAL(debug) << __FUNCTION__ << boost::format(", preset type %1%, name %2%, path %3%, is_system %4%, is_default %5% is_visible %6%")%Preset::get_type_string(m_type) %preset.name %preset.file %preset.is_system %preset.is_default %preset.is_visible;
+                    // add alias for custom filament preset
+                    set_custom_preset_alias(preset);
+                } catch (const std::ifstream::failure &err) {
+                    ++m_errors;
+                    BOOST_LOG_TRIVIAL(error) << boost::format("The user-config cannot be loaded: %1%. Reason: %2%")%preset.file %err.what();
+                    fs::path file_path(preset.file);
+                    if (!read_only && fs::exists(file_path))
+                        fs::remove(file_path);
+                    file_path.replace_extension(".info");
+                    if (!read_only && fs::exists(file_path))
+                        fs::remove(file_path);
+                    //throw Slic3r::RuntimeError(std::string("The selected preset cannot be loaded: ") + preset.file + "\n\tReason: " + err.what());
+                } catch (const std::runtime_error &err) {
+                    ++m_errors;
+                    BOOST_LOG_TRIVIAL(error) << boost::format("Failed loading the user-config file: %1%. Reason: %2%")%preset.file %err.what();
+                    //throw Slic3r::RuntimeError(std::string("Failed loading the preset file: ") + preset.file + "\n\tReason: " + err.what());
+                    fs::path file_path(preset.file);
+                    if (!read_only && fs::exists(file_path))
+                        fs::remove(file_path);
+                    file_path.replace_extension(".info");
+                    if (!read_only && fs::exists(file_path))
+                        fs::remove(file_path);
+                }
+
+                if (preset_loaded_fn != nullptr)
+                    preset_loaded_fn(preset);
+
+                presets_loaded.emplace_back(preset);
+                BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << __LINE__ << " load config successful and preset name is:" << preset.name;
             } catch (const std::runtime_error &err) {
                 errors_cummulative += err.what();
                 errors_cummulative += "\n";
             }
-        });
-
+        }
+    }
     if (presets_loaded.size() > 0)
         m_presets.insert(m_presets.end(), std::make_move_iterator(presets_loaded.begin()), std::make_move_iterator(presets_loaded.end()));
     sort_presets();
@@ -2295,10 +2167,7 @@ void PresetCollection::set_sync_info_and_save(std::string name, std::string sett
             preset->setting_id = setting_id;
             if (update_time > 0)
                 preset->updated_time = update_time;
-            if (preset->sync_info == "update")
-                preset->save(nullptr);
-            else
-                preset->save_info();
+            preset->sync_info == "update" ? preset->save(nullptr) : preset->save_info();
             break;
         }
     }
@@ -2958,18 +2827,6 @@ std::pair<Preset*, bool> PresetCollection::load_external_preset(
     return std::make_pair(&preset, false);
 }
 
-Preset& PresetCollection::append_preset(std::string &&path, const std::string &name, DynamicPrintConfig &&config)
-{
-    lock();
-    Preset &preset = m_presets.emplace_back(m_type, name, false);
-    preset.file = std::move(path);
-    preset.config = std::move(config);
-    preset.loaded = true;
-    preset.is_dirty = false;
-    unlock();
-    return preset;
-}
-
 Preset& PresetCollection::load_preset(const std::string &path, const std::string &name, DynamicPrintConfig &&config, bool select, Semver file_version)
 {
     lock();
@@ -3989,53 +3846,28 @@ bool PresetCollection::select_preset_by_name_strict(const std::string &name)
     return false;
 }
 
-std::vector<std::vector<std::string>> PresetCollection::merge_presets(const std::vector<PresetCollection*> &others, const VendorMap &new_vendors)
+// Merge one vendor's presets with the other vendor's presets, report duplicates.
+std::vector<std::string> PresetCollection::merge_presets(PresetCollection &&other, const VendorMap &new_vendors)
 {
-    auto less = [this](const Preset &a, const Preset &b) {
-        return m_type == Preset::TYPE_FILAMENT ? filament_preset_less(a, b) : a < b;
-    };
-    struct Incoming { Preset *preset; size_t source; };
-    auto incoming_less = [&less](const Incoming &a, const Incoming &b) { return less(*a.preset, *b.preset); };
-    // Each of `others` is sorted, so its presets form one sorted run.
-    std::vector<Incoming> incoming;
-    std::vector<size_t>   run_ends { 0 };
-    for (size_t source = 0; source < others.size(); ++ source) {
-        for (Preset &preset : others[source]->m_presets)
-            if (! preset.is_default && ! preset.is_external)
-                incoming.push_back({ &preset, source });
-        assert(std::is_sorted(incoming.begin() + run_ends.back(), incoming.end(), incoming_less));
-        run_ends.push_back(incoming.size());
-    }
-    // Merged pairwise and stably, so equal names stay in the order of `others`.
-    const size_t runs = others.size();
-    for (size_t width = 1; width < runs; width *= 2)
-        for (size_t i = 0; i + width < runs; i += 2 * width)
-            std::inplace_merge(incoming.begin() + run_ends[i], incoming.begin() + run_ends[i + width],
-                               incoming.begin() + run_ends[std::min(i + 2 * width, runs)], incoming_less);
-
-    std::vector<std::vector<std::string>> duplicates(others.size());
-    std::deque<Preset> merged;
-    auto own = m_presets.begin() + m_num_default_presets;
-    std::move(m_presets.begin(), own, std::back_inserter(merged));
-    // On equal names this collection's preset is kept, else the earliest of `others`,
-    // and each repeat is listed under the collection it came from.
-    for (auto next = incoming.begin(); own != m_presets.end() || next != incoming.end();) {
-        if (next == incoming.end() || (own != m_presets.end() && ! less(*next->preset, *own)))
-            merged.emplace_back(std::move(*own ++));
-        else {
-            Preset &preset = *(next ++)->preset;
+    std::vector<std::string> duplicates;
+    for (Preset &preset : other.m_presets) {
+        if (preset.is_default || preset.is_external)
+            continue;
+        Preset key(m_type, preset.name);
+        auto it = (m_type == Preset::TYPE_FILAMENT)
+            ? std::lower_bound(m_presets.begin() + m_num_default_presets, m_presets.end(), key, filament_preset_less)
+            : std::lower_bound(m_presets.begin() + m_num_default_presets, m_presets.end(), key);
+        if (it == m_presets.end() || it->name != preset.name) {
             if (preset.vendor != nullptr) {
                 // Re-assign a pointer to the vendor structure in the new PresetBundle.
                 auto it = new_vendors.find(preset.vendor->id);
                 assert(it != new_vendors.end());
                 preset.vendor = &it->second;
             }
-            merged.emplace_back(std::move(preset));
-        }
-        for (; next != incoming.end() && next->preset->name == merged.back().name; ++ next)
-            duplicates[next->source].emplace_back(next->preset->name);
+            m_presets.emplace(it, std::move(preset));
+        } else
+            duplicates.emplace_back(std::move(preset.name));
     }
-    m_presets = std::move(merged);
     return duplicates;
 }
 
@@ -4380,15 +4212,8 @@ void PhysicalPrinter::update_preset_names_in_config()
     }
 }
 
-void PhysicalPrinter::save(DynamicPrintConfig* /* parent_config */)
-{
-    InstanceLock instance_lock(user_presets_lock_path());
-    this->config.save_to_json(this->file, std::string("Physical_Printer"), std::string("User"), std::string(SLIC3R_VERSION));
-}
-
 void PhysicalPrinter::save(const std::string& file_name_from, const std::string& file_name_to)
 {
-    InstanceLock instance_lock(user_presets_lock_path());
     // rename the file
     boost::nowide::rename(file_name_from.data(), file_name_to.data());
     this->file = file_name_to;
@@ -4520,7 +4345,6 @@ void PhysicalPrinterCollection::load_printers(
                 continue;
             }
             try {
-                InstanceLock instance_lock(user_presets_lock_path());
                 PhysicalPrinter printer(name, this->default_config());
                 printer.file = dir_entry.path().string();
                 // Load the preset file, apply preset values on top of defaults.
@@ -4713,10 +4537,7 @@ bool PhysicalPrinterCollection::delete_printer(const std::string& name)
 
     const PhysicalPrinter& printer = *it;
     // Erase the preset file.
-    {
-        InstanceLock instance_lock(user_presets_lock_path());
-        boost::nowide::remove(printer.file.c_str());
-    }
+    boost::nowide::remove(printer.file.c_str());
     m_printers.erase(it);
     return true;
 }
@@ -4728,10 +4549,7 @@ bool PhysicalPrinterCollection::delete_selected_printer()
     const PhysicalPrinter& printer = this->get_selected_printer();
 
     // Erase the preset file.
-    {
-        InstanceLock instance_lock(user_presets_lock_path());
-        boost::nowide::remove(printer.file.c_str());
-    }
+    boost::nowide::remove(printer.file.c_str());
     // Remove the preset from the list.
     m_printers.erase(m_printers.begin() + m_idx_selected);
     // unselect all printers

src/libslic3r/Preset.hpp

@@ -8,7 +8,6 @@
 #include <unordered_set>
 #include <functional>
 #include <mutex>
-#include <optional>
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/filesystem/path.hpp>
 #include <boost/property_tree/ptree_fwd.hpp>
@@ -331,8 +330,7 @@ public:
 
     //BBS: add logic for only difference save
     //if parent_config is null, save all keys, otherwise, only save difference
-    // Returns false when the preset file could not be written.
-    bool                save(DynamicPrintConfig* parent_config);
+    void                save(DynamicPrintConfig* parent_config);
     void                reload(Preset const & parent);
 
     // Return a label of this preset, consisting of a name and a "(modified)" suffix, if this preset is dirty.
@@ -447,10 +445,7 @@ public:
     static std::string                      remove_suffix_modified(const std::string& name);
     static void                             normalize(DynamicPrintConfig &config);
     // Report configuration fields, which are misplaced into a wrong group, remove them from the config.
-    // `added`, when given, is the diff applied over a copy of default_config, and only
-    // its keys are checked, since no other key can be missing from default_config.
-    static std::string                      remove_invalid_keys(DynamicPrintConfig &config, const DynamicPrintConfig &default_config,
-                                                                const DynamicPrintConfig *added = nullptr);
+    static std::string                      remove_invalid_keys(DynamicPrintConfig &config, const DynamicPrintConfig &default_config);
 
     // BBS: move constructor to public
     Preset(Type type, const std::string &name, bool is_default = false) : type(type), is_default(is_default), name(name) {}
@@ -490,12 +485,6 @@ std::string get_preset_canonical_name(const std::string &preset_bare_name, const
 // Tail segment of a canonical name — what's written to the bundle's .json filename and JSON "name" field.
 std::string get_preset_bare_name(const std::string &canonical_name);
 
-// Lock file guarding every user preset file under data_dir() against other
-// running instances and the preset sync thread. Empty without a data dir, and
-// for a read-only load (the CLI), which never rewrites or deletes and may run
-// many jobs on one data dir.
-std::string user_presets_lock_path(bool read_only = false);
-
 // Resolve an origin from a directory path when the caller passes Kind::Auto.
 PresetOrigin detect_origin_from_path(const boost::filesystem::path &path, const PresetOrigin &explicit_origin = PresetOrigin());
 
@@ -812,8 +801,6 @@ public:
     // Return number of presets including the "- default -" preset.
     size_t          size() const                { return m_presets.size(); }
     bool            has_defaults_only() const   { return m_presets.size() <= m_num_default_presets; }
-    // How many presets this collection refused or repaired while loading.
-    int             error_count() const         { return m_errors; }
 
     // For Print / Filament presets, disable those, which are not compatible with the printer.
     template<typename PreferedCondition>
@@ -887,10 +874,8 @@ protected:
     // This is a temporary state, which shall be fixed immediately by the following step.
     bool            select_preset_by_name_strict(const std::string &name);
 
-    // Move the presets of `others` into this collection in one pass. A name this
-    // collection or an earlier one of `others` already has is left out, and reported
-    // in the list of the collection that repeats it.
-    std::vector<std::vector<std::string>> merge_presets(const std::vector<PresetCollection*> &others, const VendorMap &new_vendors);
+    // Merge one vendor's presets with the other vendor's presets, report duplicates.
+    std::vector<std::string> merge_presets(PresetCollection &&other, const VendorMap &new_vendors);
 
     // Update m_map_alias_to_profile_name from loaded system profiles.
 	void 			update_map_alias_to_profile_name();
@@ -905,56 +890,6 @@ protected:
     void            set_custom_preset_alias(Preset &preset);
 
 private:
-    // A preset file and its .info as read from disk, std::nullopt for one that is missing.
-    struct PresetFilesOnDisk
-    {
-        std::optional<std::string> json;
-        std::optional<std::string> info;
-
-        static PresetFilesOnDisk read(const boost::filesystem::path &file);
-        bool operator==(const PresetFilesOnDisk &rhs) const { return json == rhs.json && info == rhs.info; }
-    };
-
-    // One preset file read and flattened against the presets already in this
-    // collection, before anything the collection shares has been touched.
-    struct UserPresetLoad
-    {
-        Preset      preset;
-        // Joins the collection. A file that threw partway still joins it, without
-        // the steps that did not run.
-        bool        install { false };
-        // The whole of the load ran, so the preset is ready to be aliased.
-        bool        complete { false };
-        // A filament preset that named no compatible printer and was given one from
-        // its name, which commit writes back to its file.
-        bool        save_compatible_printers { false };
-        // Unreadable, so commit removes it and its .info file.
-        bool        discard_file { false };
-        // The .info file read beside the preset, which commit logs.
-        std::string info_file;
-        // Both files as they were before the preset was read from them. Resolve runs
-        // without the instance lock, so commit compares this with the disk under it.
-        PresetFilesOnDisk on_disk;
-        // Counted and logged by commit, in the order the directory listed the files.
-        std::vector<std::string>   errors;
-        PresetsConfigSubstitutions substitutions;
-    };
-
-    // Read and flatten one preset file. It reads only, and resolves against the presets
-    // loaded before this pass, never another file of the same pass, so the files of a
-    // pass are independent of each other.
-    UserPresetLoad  resolve_user_preset(const boost::filesystem::path &file, const std::string &canonical_name,
-                                        const PresetOrigin &load_origin, ForwardCompatibilitySubstitutionRule substitution_rule,
-                                        const std::string &extruder_id_name, const std::string &extruder_variant_name,
-                                        std::set<std::string> *key_set1, std::set<std::string> *key_set2) const;
-
-    // Install one resolved preset. The collection, its alias maps, the error count
-    // and the preset files on disk are touched here and only here.
-    void            commit_user_preset(UserPresetLoad &&loaded, std::deque<Preset> &presets_loaded,
-                                       PresetsConfigSubstitutions &substitutions,
-                                       const std::function<void(Preset&)> &preset_loaded_fn,
-                                       bool read_only);
-
     std::string canonical_preset_name(const std::string &name, const PresetOrigin &load_origin = PresetOrigin()) const;
 
     // Comparator that sorts "Generic " prefixed presets before others, then alphabetically within each group.
@@ -966,10 +901,6 @@ private:
         return a.name < b.name;
     }
 
-    // Append a preset without keeping the collection sorted, for a caller installing
-    // many at once; find_preset() is unusable until sort_presets() runs.
-    Preset& append_preset(std::string &&path, const std::string &name, DynamicPrintConfig &&config);
-
     // Sort presets: filament presets use generic-first ordering, others sort alphabetically.
     void sort_presets() {
         if (m_type == Preset::TYPE_FILAMENT)
@@ -1123,7 +1054,7 @@ public:
 
     //BBS: change to json format
     //void                save() { this->config.save(this->file); }
-    void                save(DynamicPrintConfig* parent_config);
+    void                save(DynamicPrintConfig* parent_config) { this->config.save_to_json(this->file, std::string("Physical_Printer"), std::string("User"), std::string(SLIC3R_VERSION)); }
     void                save(const std::string& file_name_from, const std::string& file_name_to);
 
     void                update_from_preset(const Preset& preset);

src/libslic3r/PresetBundle.hpp

@@ -15,7 +15,6 @@
 #include <unordered_map>
 #include <optional>
 #include <array>
-#include <atomic>
 #include <boost/filesystem/path.hpp>
 #include <unordered_set>
 
@@ -623,180 +622,36 @@ public:
     // default_filament_profile must resolve to a system filament.
     bool check_printer_default_materials() const;
 
-    // One vendor to load, and the directory it is installed in.
-    struct VendorSource
-    {
-        std::string             name;
-        boost::filesystem::path dir;
-    };
-
-    // Load `vendors` into this bundle, the Orca filament library directly and every
-    // other vendor in parallel into a bundle of its own that inherits from it, merged
-    // in the order given. A vendor that cannot be loaded has its error added to the
-    // returned text, or thrown in validation mode, and its name to `failed`; it is
-    // left out, except for the library, which keeps what it installed before the
-    // failure. Once `cancel` is set, no further vendor starts loading.
-    std::pair<PresetsConfigSubstitutions, std::string> load_vendors(const std::vector<VendorSource>& vendors,
-        ForwardCompatibilitySubstitutionRule compatibility_rule, bool allow_cache,
-        const std::atomic<bool>* cancel = nullptr, std::vector<std::string>* failed = nullptr);
+    // Merge one vendor's presets with the other vendor's presets, report duplicates.
+    // Public so per-vendor-cache consumers (e.g. the setup wizard) can assemble a
+    // bundle out of several per-vendor caches loaded into separate PresetBundle instances.
+    std::vector<std::string>    merge_presets(PresetBundle &&other);
 
 private:
-    // Move the presets and vendor profiles of `others` into this bundle, in one pass
-    // over each collection. A preset whose name this bundle or an earlier one of
-    // `others` already has is left out and listed under the bundle that repeats it.
-    std::vector<std::vector<std::string>> merge_presets(const std::vector<PresetBundle*> &others);
+    // Load one vendor from the preset cache installed in `dir`, judged against
+    // the vendor profile there. False, with this bundle left clean, when there
+    // is no usable cache and the vendor has to be parsed. This is how
+    // load_vendor_configs_from_json reads a cache.
+    bool load_vendor_cache(const boost::filesystem::path& dir, const std::string& vendor_name, const PresetBundle* base_bundle);
 
-    // What parsing one entry's JSON sub-file reported. Its errors and warnings are
-    // logged when the entry installs, so they come out in listing order with the
-    // entry's install errors, as parsing and installing one entry at a time leaves them.
-    struct EntryParse
-    {
-        ConfigSubstitutions      substitutions;
-        // Counted in the bundle's error count.
-        std::vector<std::string> errors;
-        std::vector<std::string> warnings;
-    };
-
-    // An EntryParse for each entry of the VendorCacheData list of the same name.
-    struct VendorParse
-    {
-        std::vector<EntryParse> process_entries;
-        std::vector<EntryParse> filament_entries;
-        std::vector<EntryParse> machine_entries;
-    };
-
-    // One vendor read from its cache or its JSONs by read_vendor, for
-    // install_vendor_read to install.
-    struct VendorRead
-    {
-        std::string                          dir;
-        std::string                          vendor_name;
-        LoadConfigBundleAttributes           flags;
-        ForwardCompatibilitySubstitutionRule compatibility_rule;
-        // The errors this bundle had counted before the read, which the cache stamp leaves out.
-        int                                  errors_at_entry { 0 };
-        // A whole-vendor load, which can read a cache and write one.
-        bool                                 cacheable { false };
-        // Read from the cache at cache_path, which install can still reject.
-        bool                                 from_cache { false };
-        std::string                          cache_path;
-        // Only the vendor profile was asked for.
-        bool                                 vendor_only { false };
-        VendorCacheData                      data;
-        // What each entry's JSON parse reported, and whether and with which version
-        // the cache is written once the entries install.
-        VendorParse                          parsed;
-        bool                                 will_cache { false };
-        std::string                          version;
-        // The sub-file the parse stopped at, its kind, why, and the errors it reported.
-        std::string                          reason;
-        std::string                          failed_subfile;
-        const char*                          failed_kind { nullptr };
-        std::vector<std::string>             failed_errors;
-    };
-
-    // Read a vendor into this bundle's vendor profiles and `data`, from its cache
-    // when one covers it, else from its JSONs; nothing is installed. Throws
-    // ConfigurationError when the vendor's own JSON cannot be parsed.
-    VendorRead read_vendor(const std::string& dir, const std::string& vendor_name, LoadConfigBundleAttributes flags,
-                           ForwardCompatibilitySubstitutionRule compatibility_rule, bool allow_cache);
-
-    // Parse the vendor's JSONs into `read`, up to the first sub-file that fails.
-    void parse_vendor_json(VendorRead& read);
-
-    // Install what read_vendor read, against base_bundle's filament library. A cache
-    // that cannot be installed is replaced by a parse of the JSONs. Throws
-    // ConfigurationError at the first entry that cannot be installed, or after
-    // installing the entries before a sub-file that could not be parsed.
-    std::pair<PresetsConfigSubstitutions, size_t> install_vendor_read(VendorRead&& read, const PresetBundle* base_bundle);
-
-    // Install a cache's entries. False, with this bundle left clean, when one of them
-    // cannot be installed.
-    bool install_vendor_cache(const std::string& cache_path, const std::string& vendor_name, VendorCacheData&& data,
-                              const PresetBundle* base_bundle);
-
-    // Log and count errors reported by a resolve or a parse.
-    void log_errors(const std::vector<std::string>& errors);
-
-    // The state of installing one collection of one vendor, which
-    // resolve_vendor_preset reads through a const reference and only
-    // commit_vendor_preset writes.
-    struct VendorInstall
-    {
-        // The directory holding <vendor_name>/, whose sub-paths the entries name.
-        std::string                path;
-        std::string                vendor_name;
-        const VendorProfile*       vendor_profile;
-        const PresetBundle*        base_bundle;
-        LoadConfigBundleAttributes flags;
-        PresetCollection*          presets;
-        // The Orca filament library, which keeps every config for other vendors to
-        // resolve against.
-        bool                       is_from_lib;
-        PresetsConfigSubstitutions* substitutions;
-        // The names some entry inherits / includes, the only ones whose configs /
-        // include diffs are looked up again.
-        std::set<std::string>      inherited;
-        std::set<std::string>      included;
-        std::map<std::string, DynamicPrintConfig> config_maps;
-        std::map<std::string, DynamicPrintConfig> include_maps;
-        std::map<std::string, std::string>        filament_id_maps;
-        std::unordered_set<std::string>           installed_names;
-        size_t                     count { 0 };
-    };
-
-    // Install a vendor's source-form entries, parsed from its JSON or read from its
-    // cache: processes, then filaments, then printers. Both loads go through here,
-    // so a cache-loaded bundle cannot come out different from a JSON-loaded one.
-    // `parsed` is given for entries parsed just now. `complete` says the entries
-    // are the vendor's whole lists; only then are the filament library's configs
-    // and filament ids left in m_config_maps and m_filament_id_maps. Returns the
-    // number of presets installed, and throws ConfigurationError at the first
-    // entry that cannot be installed.
-    size_t install_vendor(const std::string& path, const std::string& vendor_name, const PresetBundle* base_bundle,
-                          LoadConfigBundleAttributes flags, const VendorCacheData& entries,
-                          VendorParse* parsed, bool complete, PresetsConfigSubstitutions& substitutions);
-
-    // Install one collection's entries in the order they are listed.
-    void install_vendor_entries(VendorInstall& install, const std::vector<CachedPreset>& entries,
-                                std::vector<EntryParse>* parsed);
-
-    // One entry flattened against the preset it inherits, before anything this
-    // bundle shares has been touched.
-    struct PresetInstall
-    {
-        DynamicPrintConfig       config;
-        std::string              file_path;
-        // Empty when the preset is its own alias.
-        std::string              alias;
-        std::string              filament_id;
-        std::vector<std::string> renamed_from;
-        // Reported by commit, so resolving entries together leaves the log and
-        // the error count as one entry at a time produces them.
-        std::vector<std::string> errors;
-        // What a base states for the presets that include it, when it is retained.
-        std::optional<DynamicPrintConfig> included;
-        // The config kept for the entries that inherit this one, or for other
-        // vendors when this is the filament library.
-        std::optional<DynamicPrintConfig> retained;
-        // Not instantiated, so it contributes a config and no preset.
-        bool                     config_only { false };
-        // Non-empty when the entry is rejected, and says why.
-        std::string              reason;
-    };
-
-    // Flatten one entry against the config it inherits, from this collection's
-    // config_maps or base_bundle's filament library, with the include diffs it
-    // names layered in. It looks up nothing but the names the entry inherits and
-    // includes, and writes nothing.
-    PresetInstall resolve_vendor_preset(const CachedPreset& entry, const VendorInstall& install) const;
-
-    // Install a resolved entry. The collections, the maps in `install` and the
-    // error count are touched here and only here, one entry at a time.
-    // Presets are appended, so a repeated name is caught with `installed_names`,
-    // and the collection is sorted once every entry is in.
-    std::string commit_vendor_preset(const CachedPreset& entry, PresetInstall&& resolved,
-                                     ConfigSubstitutions&& substitutions, VendorInstall& install);
+    // Load one source-form preset entry into this bundle: resolve `inherits`
+    // and `include`, flatten, validate and register the preset. Returns the
+    // reason loading failed, empty on success. See the definition for the
+    // sharing contract between the JSON parse and the cache load.
+    // retain_configs / retain_includes, when non-null, name the only presets
+    // registered into config_maps / include_maps (a config copy each). The
+    // cache load passes the names its entries inherit / include — the only
+    // ones ever looked up again; the JSON parse retains all, not knowing what
+    // later subfiles name.
+    std::string load_vendor_preset(const CachedPreset& entry,
+        const std::string& path, const std::string& vendor_name,
+        const PresetBundle* base_bundle,
+        LoadConfigBundleAttributes flags,
+        ConfigSubstitutionContext& substitution_context, PresetsConfigSubstitutions& substitutions,
+        std::map<std::string, DynamicPrintConfig>& config_maps, std::map<std::string, DynamicPrintConfig>& include_maps,
+        std::map<std::string, std::string>& filament_id_maps,
+        PresetCollection* presets_collection, size_t& count, bool is_from_lib,
+        const std::set<std::string>* retain_configs = nullptr, const std::set<std::string>* retain_includes = nullptr);
 
     // Clear every collection's m_printer_hold_alias, which reset() leaves alone.
     void clear_printer_hold_aliases();

src/libslic3r/PresetCacheFormat.cpp

@@ -400,24 +400,46 @@ bool write_cache_blob(const std::string& path, const std::string& blob)
 {
     boost::crc_32_type crc;
     crc.process_bytes(blob.data(), blob.size());
-    // Written beside the target and moved into place: a cache is truncated and
-    // rewritten in full, so a write that dies partway would otherwise leave a
-    // header claiming more body than the file holds.
+    // Written beside the target and moved into place, as AppConfig::save does:
+    // a cache is truncated and rewritten in full, so a write that dies partway
+    // would otherwise leave a header claiming more body than the file holds.
+    // The PID suffix also keeps two instances writing the same vendor from
+    // interleaving.
+    const std::string tmp_path = path + "." + std::to_string(get_current_pid()) + ".tmp";
     try {
         boost::filesystem::create_directories(boost::filesystem::path(path).parent_path());
-        CacheFileHeader fhdr;
-        fhdr.magic     = CACHE_MAGIC;
-        fhdr.version   = CACHE_VERSION;
-        fhdr.data_size = static_cast<uint64_t>(blob.size());
-        fhdr.crc32     = crc.checksum();
-        const std::string_view header(reinterpret_cast<const char*>(&fhdr), sizeof(fhdr));
-        if (const std::error_code ec = write_file_atomically(path, { header, std::string_view(blob) }, /*binary=*/true)) {
-            BOOST_LOG_TRIVIAL(warning) << "VendorCacheFile: write failed (" << path << "): " << ec.message();
+        {
+            boost::nowide::ofstream ofs(tmp_path, std::ios::binary | std::ios::trunc);
+            if (!ofs.is_open()) {
+                BOOST_LOG_TRIVIAL(warning) << "VendorCacheFile: cannot open for writing: " << tmp_path;
+                return false;
+            }
+            CacheFileHeader fhdr;
+            fhdr.magic     = CACHE_MAGIC;
+            fhdr.version   = CACHE_VERSION;
+            fhdr.data_size = static_cast<uint64_t>(blob.size());
+            fhdr.crc32     = crc.checksum();
+            ofs.write(reinterpret_cast<const char*>(&fhdr), sizeof(fhdr));
+            ofs.write(blob.data(), static_cast<std::streamsize>(blob.size()));
+            ofs.close();   // flush; close() raises failbit on error
+            if (! ofs.good()) {
+                BOOST_LOG_TRIVIAL(warning) << "VendorCacheFile: write failed (" << tmp_path << ")";
+                boost::system::error_code ec;
+                boost::filesystem::remove(tmp_path, ec);
+                return false;
+            }
+        }
+        if (const std::error_code ec = rename_file(tmp_path, path)) {
+            BOOST_LOG_TRIVIAL(warning) << "VendorCacheFile: could not move " << tmp_path << " into place: " << ec.message();
+            boost::system::error_code rm;
+            boost::filesystem::remove(tmp_path, rm);
             return false;
         }
         return true;
     } catch (const std::exception& e) {
         BOOST_LOG_TRIVIAL(warning) << "VendorCacheFile: write failed (" << path << "): " << e.what();
+        boost::system::error_code ec;
+        boost::filesystem::remove(tmp_path, ec);
         return false;
     }
 }

src/libslic3r/PresetCacheFormat.hpp

@@ -109,7 +109,7 @@ void skip_config(cereal::BinaryInputArchive& ar, const CacheDictionary& dict);
 
 // One preset as its JSON subfile states it: the config diff, the names of the
 // preset it inherits and the presets it includes, and the parse metadata —
-// everything PresetBundle::parse_vendor_json extracts and
+// everything the parse phase of load_vendor_configs_from_json extracts and
 // nothing it derives. Inheritance and includes are resolved when the entry is
 // installed, against whatever filament library is loaded then, so a cache
 // carries no other vendor's values and no other vendor's update can make it

src/libslic3r/PrintObject.cpp

@@ -30,6 +30,7 @@
 
 #include <cstddef>
 #include <float.h>
+#include <array>
 #include <iterator>
 #include <mutex>
 #include <string>
@@ -42,6 +43,7 @@
 #include <boost/log/trivial.hpp>
 
 #include <tbb/parallel_for.h>
+#include <tbb/parallel_invoke.h>
 #include <tbb/spin_mutex.h>
 #include <tbb/concurrent_unordered_set.h>
 
@@ -1664,7 +1666,9 @@ void PrintObject::detect_surfaces_type()
     bool interface_shells = ! spiral_mode && m_config.interface_shells.value;
     size_t num_layers     = spiral_mode ? std::min(size_t(this->printing_region(0).config().bottom_shell_layers), m_layers.size()) : m_layers.size();
 
-    for (size_t region_id = 0; region_id < this->num_printing_regions(); ++ region_id) {
+    // The regions of a layer do not see each other here, and a layer cut through a fine relief takes far longer than the
+    // others, so the regions run next to each other instead of one after another, each still over all layers.
+    tbb::parallel_for(size_t(0), this->num_printing_regions(), [&](size_t region_id) {
         BOOST_LOG_TRIVIAL(debug) << "Detecting solid surfaces for region " << region_id << " in parallel - start";
 #ifdef SLIC3R_DEBUG_SLICE_PROCESSING
         for (Layer *layer : m_layers)
@@ -1722,7 +1726,7 @@ void PrintObject::detect_surfaces_type()
                     if (upper_layer) {
                         ExPolygons upper_slices = interface_shells ?
                             diff_ex(layerm_slices_surfaces, upper_layer->m_regions[region_id]->slices.surfaces, ApplySafetyOffset::Yes) :
-                            diff_ex(layerm_slices_surfaces, upper_layer->lslices, ApplySafetyOffset::Yes);
+                            diff_ex_by_piece(layerm_slices_surfaces, to_polygons(upper_layer->lslices), ApplySafetyOffset::Yes);
                         surfaces_append(top, opening_ex(upper_slices, offset), stTop);
                     } else {
                         // if no upper layer, all surfaces of this one are solid
@@ -1748,7 +1752,7 @@ void PrintObject::detect_surfaces_type()
                         surfaces_append(
                             bottom,
                             opening_ex(
-                                diff_ex(layerm_slices_surfaces, lower_layer->lslices, ApplySafetyOffset::Yes),
+                                diff_ex_by_piece(layerm_slices_surfaces, to_polygons(lower_layer->lslices), ApplySafetyOffset::Yes),
                                 offset),
                             surface_type_bottom_other);
                         // if user requested internal shells, we need to identify surfaces
@@ -1779,34 +1783,44 @@ void PrintObject::detect_surfaces_type()
                     // and top surfaces; let's do an intersection to discover them and consider them
                     // as bottom surfaces (to allow for bridge detection)
                     if (! top.empty() && ! bottom.empty()) {
-                        const auto cracks = intersection_ex(top, bottom);
+                        const auto cracks = intersection_ex_by_piece(to_expolygons(top), to_polygons(bottom));
                         if (!cracks.empty()) {
                             if (lower_layer) { // Only detect small cracks for non-first layer, because first layer should always be bottom
                                 const float small_crack_threshold = -layerm->flow(frExternalPerimeter).scaled_width() * 1.5;
                                 
+                                // Only the bottom surfaces near a crack can take part: one that contains it must contain its box,
+                                // and one whose box misses the grown crack is left unchanged by removing it. A layer cut through
+                                // a fine relief has thousands of both, which made this loop quadratic.
                                 for (const auto& crack : cracks) {
                                     if (offset_ex(crack, small_crack_threshold).empty()) {
                                         // For small cracks, if it's part of a large bottom surface, then it should be added to bottom as well
-                                        if (std::any_of(bottom.begin(), bottom.end(), [&crack, small_crack_threshold](const Surface& s) {
+                                        const BoundingBox crack_bbox = get_extents(crack);
+                                        if (std::any_of(bottom.begin(), bottom.end(), [&crack, &crack_bbox, small_crack_threshold](const Surface& s) {
                                                 const auto& se = s.expolygon;
-                                                return diff_ex(crack, se, ApplySafetyOffset::Yes).empty()
+                                                return get_extents(se).inflated(SCALED_EPSILON).contains(crack_bbox)
+                                                    && diff_ex(crack, se, ApplySafetyOffset::Yes).empty()
                                                     && se.area() > crack.area() * 2
                                                     && !offset_ex(diff_ex(se, crack), small_crack_threshold).empty();
                                         })) continue;
 
                                         // Crack too small, leave it as part of the top surface, remove it from bottom surfaces
+                                        const ExPolygons  grown_crack = offset_ex(crack, -small_crack_threshold);
+                                        const BoundingBox grown_bbox  = get_extents(grown_crack);
                                         Surfaces bot_tmp;
                                         for (auto& b : bottom) {
-                                            surfaces_append(bot_tmp, diff_ex(b.expolygon, offset_ex(crack, -small_crack_threshold)), b.surface_type);
+                                            if (get_extents(b.expolygon).overlap(grown_bbox))
+                                                surfaces_append(bot_tmp, diff_ex(b.expolygon, grown_crack), b.surface_type);
+                                            else
+                                                bot_tmp.emplace_back(std::move(b));
                                         }
                                         bottom = std::move(bot_tmp);
                                     }
                                 }
                             }
 
-                            Polygons top_polygons = to_polygons(std::move(top));
+                            ExPolygons top_expolygons = to_expolygons(std::move(top));
                             top.clear();
-                            surfaces_append(top, diff_ex(top_polygons, bottom), stTop);
+                            surfaces_append(top, diff_ex_by_piece(top_expolygons, to_polygons(bottom)), stTop);
                         }
                     }
 
@@ -1897,7 +1911,7 @@ void PrintObject::detect_surfaces_type()
                     {
                         Polygons topbottom = to_polygons(top);
                         polygons_append(topbottom, to_polygons(bottom));
-                        surfaces_append(surfaces_out, diff_ex(surfaces_prev_expolys, topbottom), stInternal);
+                        surfaces_append(surfaces_out, diff_ex_by_piece(surfaces_prev_expolys, topbottom), stInternal);
                     }
 
                     surfaces_append(surfaces_out, std::move(top));
@@ -2074,29 +2088,31 @@ void PrintObject::detect_surfaces_type()
                 }
             }
             );
-            // ==============================================================================================================
-            // === ORCA: Interim workaround - for now the new stInternalAfterExternalBridge surfaace is re-classified  ==============
-            // === back to a bottom bridge. As a starting point, this improves bridging reliability as it extrudes ==========
-            // === two external bridge layers. However, TODO: Implement a new surface type throughout the codebase ==========
-            // ==============================================================================================================
-            for (size_t region_id = 0; region_id < this->num_printing_regions(); ++region_id) {
-                tbb::parallel_for( tbb::blocked_range<size_t>(0, m_layers.size()), [this, region_id](const tbb::blocked_range<size_t> &range) {
-                    for (size_t idx_layer = range.begin(); idx_layer < range.end(); ++idx_layer) {
-                        Surfaces &surfs = m_layers[idx_layer]->m_regions[region_id]->slices.surfaces;
-                        for (Surface &s : surfs) {
-                            if (s.surface_type == stInternalAfterExternalBridge) {
-                                s.surface_type = stBottomBridge;
-                            }
-                        }
-                    }
-                }
-              );
-            }
         }
         // ==============================================================================================================
         // === ORCA: End of second external bridge layer changes  =======================================================
         // ==============================================================================================================
         
+    }); // for each this->print->region_count
+
+    // ==============================================================================================================
+    // === ORCA: Interim workaround - for now the new stInternalAfterExternalBridge surfaace is re-classified  ==============
+    // === back to a bottom bridge. As a starting point, this improves bridging reliability as it extrudes ==========
+    // === two external bridge layers. However, TODO: Implement a new surface type throughout the codebase ==========
+    // ==============================================================================================================
+    // Once all the regions have their second bridge layer, and before their slices are trimmed into fill surfaces below.
+    if ((this->config().enable_extra_bridge_layer.value == eblApplyToAll) || (this->config().enable_extra_bridge_layer.value == eblExternalBridgeOnly)) {
+        tbb::parallel_for(tbb::blocked_range<size_t>(0, m_layers.size()), [this](const tbb::blocked_range<size_t> &range) {
+            for (size_t idx_layer = range.begin(); idx_layer < range.end(); ++idx_layer)
+                for (LayerRegion *layerm : m_layers[idx_layer]->regions())
+                    for (Surface &s : layerm->slices.surfaces)
+                        if (s.surface_type == stInternalAfterExternalBridge)
+                            s.surface_type = stBottomBridge;
+        });
+        m_print->throw_if_canceled();
+    }
+
+    tbb::parallel_for(size_t(0), this->num_printing_regions(), [&](size_t region_id) {
         BOOST_LOG_TRIVIAL(debug) << "Detecting solid surfaces for region " << region_id << " - clipping in parallel - start";
         // Fill in layerm->fill_surfaces by trimming the layerm->slices by the cummulative layerm->fill_surfaces.
         tbb::parallel_for(
@@ -2113,7 +2129,7 @@ void PrintObject::detect_surfaces_type()
             });
         m_print->throw_if_canceled();
         BOOST_LOG_TRIVIAL(debug) << "Detecting solid surfaces for region " << region_id << " - clipping in parallel - end";
-    } // for each this->print->region_count
+    });
 
     // Mark the object to have the region slices classified (typed, which also means they are split based on whether they are supported, bridging, top layers etc.)
     m_typed_slices = true;
@@ -2180,8 +2196,10 @@ void PrintObject::process_external_surfaces()
 	    BOOST_LOG_TRIVIAL(debug) << "Collecting surfaces covered with extrusions in parallel - end";
 	}
 
-	for (size_t region_id = 0; region_id < this->num_printing_regions(); ++region_id) {
-        BOOST_LOG_TRIVIAL(debug) << "Processing external surfaces for region " << region_id << " in parallel - start";
+    BOOST_LOG_TRIVIAL(debug) << "Processing external surfaces in parallel - start";
+    // The regions of a layer do not see each other here, and a layer cut through a fine relief takes far longer than the
+    // others, so the regions run next to each other instead of one after another, each still over all layers.
+    tbb::parallel_for(size_t(0), this->num_printing_regions(), [this, &surfaces_covered](size_t region_id) {
         tbb::parallel_for(
             tbb::blocked_range<size_t>(0, m_layers.size()),
             [this, &surfaces_covered, region_id](const tbb::blocked_range<size_t>& range) {
@@ -2196,9 +2214,9 @@ void PrintObject::process_external_surfaces()
                 }
             }
         );
-        m_print->throw_if_canceled();
-        BOOST_LOG_TRIVIAL(debug) << "Processing external surfaces for region " << region_id << " in parallel - end";
-    }
+    });
+    m_print->throw_if_canceled();
+    BOOST_LOG_TRIVIAL(debug) << "Processing external surfaces in parallel - end";
 }
 
 void PrintObject::discover_vertical_shells()
@@ -2237,10 +2255,10 @@ void PrintObject::discover_vertical_shells()
             // The "ensure vertical wall thickness" feature is not applicable to any of the regions. Quit.
             return;
         BOOST_LOG_TRIVIAL(debug) << "Discovering vertical shells in parallel - start : cache top / bottom";
-        //FIXME Improve the heuristics for a grain size.
-        size_t grain_size = std::max(num_layers / 16, size_t(1));
+        // One layer per task: on a layer cut through a fine relief the unions below take far longer than elsewhere, and a
+        // few such layers next to each other must not end up in one task.
         tbb::parallel_for(
-            tbb::blocked_range<size_t>(0, num_layers, grain_size),
+            tbb::blocked_range<size_t>(0, num_layers, 1),
             [this, &cache_top_botom_regions](const tbb::blocked_range<size_t>& range) {
                 const std::initializer_list<SurfaceType> surfaces_bottom { stBottom, stBottomBridge };
                 const size_t num_regions = this->num_printing_regions();
@@ -2248,67 +2266,198 @@ void PrintObject::discover_vertical_shells()
                     m_print->throw_if_canceled();
                     const Layer                      &layer = *m_layers[idx_layer];
                     DiscoverVerticalShellsCacheEntry &cache = cache_top_botom_regions[idx_layer];
-                    // Simulate single set of perimeters over all merged regions.
-                    float                             perimeter_offset = 0.f;
-                    float                             perimeter_min_spacing = FLT_MAX;
+                    const auto top_bottom_expansion = [&layer](size_t region_id) {
+                        return float(layer.m_regions[region_id]->flow(frSolidInfill).scaled_spacing()) * top_bottom_expansion_coeff;
+                    };
 #ifdef SLIC3R_DEBUG_SLICE_PROCESSING
                     static size_t debug_idx = 0;
                     ++ debug_idx;
 #endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
-                    for (size_t region_id = 0; region_id < num_regions; ++ region_id) {
-                        LayerRegion &layerm               = *layer.m_regions[region_id];
-                        float        top_bottom_expansion = float(layerm.flow(frSolidInfill).scaled_spacing()) * top_bottom_expansion_coeff;
-                        // Top surfaces.
-                        append(cache.top_surfaces, offset(layerm.slices.filter_by_type(stTop), top_bottom_expansion));
-//                        append(cache.top_surfaces, offset(layerm.fill_surfaces.filter_by_type(stTop), top_bottom_expansion));
-                        // Bottom surfaces.
-                        append(cache.bottom_surfaces, offset(layerm.slices.filter_by_types(surfaces_bottom), top_bottom_expansion));
-//                        append(cache.bottom_surfaces, offset(layerm.fill_surfaces.filter_by_types(surfaces_bottom), top_bottom_expansion));
-                        // Calculate the maximum perimeter offset as if the slice was extruded with a single extruder only.
-                        // First find the maxium number of perimeters per region slice.
-                        unsigned int perimeters = 0;
-                        for (Surface &s : layerm.slices.surfaces)
-                            perimeters = std::max<unsigned int>(perimeters, s.extra_perimeters);
-                        perimeters += layerm.region().config().wall_loops.value;
-                        // Then calculate the infill offset.
-                        if (perimeters > 0) {
-                            Flow extflow = layerm.flow(frExternalPerimeter);
-                            Flow flow    = layerm.flow(frPerimeter);
-                            perimeter_offset = std::max(perimeter_offset,
-                                0.5f * float(extflow.scaled_width() + extflow.scaled_spacing()) + (float(perimeters) - 1.f) * flow.scaled_spacing());
-                            perimeter_min_spacing = std::min(perimeter_min_spacing, float(std::min(extflow.scaled_spacing(), flow.scaled_spacing())));
-                        }
-                        polygons_append(cache.holes, to_polygons(layerm.fill_expolygons));
-                    }
-                    // Save some computing time by reducing the number of polygons.
-                    cache.top_surfaces    = union_(cache.top_surfaces);
-                    cache.bottom_surfaces = union_(cache.bottom_surfaces);
-                    // For a multi-material print, simulate perimeter / infill split as if only a single extruder has been used for the whole print.
-                    if (perimeter_offset > 0.) {
-                        // The layer.lslices are forced to merge by expanding them first.
-                        polygons_append(cache.holes, offset2(layer.lslices, 0.3f * perimeter_min_spacing, - perimeter_offset - 0.3f * perimeter_min_spacing));
+                    // The top surfaces, the bottom surfaces and the holes are independent of each other.
+                    tbb::parallel_invoke(
+                        [&]() {
+                            for (size_t region_id = 0; region_id < num_regions; ++ region_id)
+                                append(cache.top_surfaces, offset(layer.m_regions[region_id]->slices.filter_by_type(stTop), top_bottom_expansion(region_id)));
+//                              append(cache.top_surfaces, offset(layerm.fill_surfaces.filter_by_type(stTop), top_bottom_expansion));
+                            // Save some computing time by reducing the number of polygons.
+                            cache.top_surfaces = union_(cache.top_surfaces);
+                        },
+                        [&]() {
+                            for (size_t region_id = 0; region_id < num_regions; ++ region_id)
+                                append(cache.bottom_surfaces, offset(layer.m_regions[region_id]->slices.filter_by_types(surfaces_bottom), top_bottom_expansion(region_id)));
+//                              append(cache.bottom_surfaces, offset(layerm.fill_surfaces.filter_by_types(surfaces_bottom), top_bottom_expansion));
+                            cache.bottom_surfaces = union_(cache.bottom_surfaces);
+                        },
+                        [&]() {
+                            // Simulate single set of perimeters over all merged regions.
+                            float perimeter_offset      = 0.f;
+                            float perimeter_min_spacing = FLT_MAX;
+                            for (size_t region_id = 0; region_id < num_regions; ++ region_id) {
+                                const LayerRegion &layerm = *layer.m_regions[region_id];
+                                // Calculate the maximum perimeter offset as if the slice was extruded with a single extruder only.
+                                // First find the maxium number of perimeters per region slice.
+                                unsigned int perimeters = 0;
+                                for (const Surface &s : layerm.slices.surfaces)
+                                    perimeters = std::max<unsigned int>(perimeters, s.extra_perimeters);
+                                perimeters += layerm.region().config().wall_loops.value;
+                                // Then calculate the infill offset.
+                                if (perimeters > 0) {
+                                    Flow extflow = layerm.flow(frExternalPerimeter);
+                                    Flow flow    = layerm.flow(frPerimeter);
+                                    perimeter_offset = std::max(perimeter_offset,
+                                        0.5f * float(extflow.scaled_width() + extflow.scaled_spacing()) + (float(perimeters) - 1.f) * flow.scaled_spacing());
+                                    perimeter_min_spacing = std::min(perimeter_min_spacing, float(std::min(extflow.scaled_spacing(), flow.scaled_spacing())));
+                                }
+                                polygons_append(cache.holes, to_polygons(layerm.fill_expolygons));
+                            }
+                            // For a multi-material print, simulate perimeter / infill split as if only a single extruder has been used for the whole print.
+                            if (perimeter_offset > 0.) {
+                                // The layer.lslices are forced to merge by expanding them first.
+                                polygons_append(cache.holes, offset2(layer.lslices, 0.3f * perimeter_min_spacing, - perimeter_offset - 0.3f * perimeter_min_spacing));
 #ifdef SLIC3R_DEBUG_SLICE_PROCESSING
-                        {
-                            Slic3r::SVG svg(debug_out_path("discover_vertical_shells-extra-holes-%d.svg", debug_idx), get_extents(layer.lslices));
-                            svg.draw(layer.lslices, "blue");
-                            svg.draw(union_ex(cache.holes), "red");
-                            svg.draw_outline(union_ex(cache.holes), "black", "blue", scale_(0.05));
-                            svg.Close();
-                        }
+                                {
+                                    Slic3r::SVG svg(debug_out_path("discover_vertical_shells-extra-holes-%d.svg", debug_idx), get_extents(layer.lslices));
+                                    svg.draw(layer.lslices, "blue");
+                                    svg.draw(union_ex(cache.holes), "red");
+                                    svg.draw_outline(union_ex(cache.holes), "black", "blue", scale_(0.05));
+                                    svg.Close();
+                                }
 #endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
-                    }
-                    cache.holes = union_(cache.holes);
+                            }
+                            cache.holes = union_(cache.holes);
+                        });
                 }
             });
         m_print->throw_if_canceled();
         BOOST_LOG_TRIVIAL(debug) << "Discovering vertical shells in parallel - end : cache top / bottom";
     }
 
-    for (size_t region_id = 0; region_id < this->num_printing_regions(); ++ region_id) {
+    // With one top/bottom cache for all regions, the shell and hole accumulation in the loop below depends on nothing
+    // region-specific but the shell settings and the external perimeter spacing, so a region sharing them with an earlier
+    // one reuses its result instead of repeating it: that accumulation is a union over several layers of top/bottom
+    // surfaces, and a multi-material print has a region per filament.
+    using AccumulationKey = std::array<double, 5>;
+    struct ShellAccumulation
+    {
+        AccumulationKey key;
+        Polygons        shell;
+        Polygons        holes;
+    };
+    const auto accumulation_key = [](const PrintRegionConfig &region_config, const LayerRegion *layerm) {
+        return AccumulationKey{ double(region_config.top_shell_layers.value), region_config.top_shell_thickness.value,
+                                double(region_config.bottom_shell_layers.value), region_config.bottom_shell_thickness.value,
+                                double(layerm->flow(frExternalPerimeter).scaled_spacing()) };
+    };
+    const auto accumulate_shell = [this, &cache_top_botom_regions](size_t idx_layer, const PrintRegionConfig &region_config,
+                                                                   const LayerRegion *layerm, Polygons &shell, Polygons &holes) {
+        const Layer *layer = m_layers[idx_layer];
+    			        polygons_append(holes, cache_top_botom_regions[idx_layer].holes);
+                        auto combine_holes = [&holes](const Polygons &holes2) {
+                            if (holes.empty() || holes2.empty())
+                                holes.clear();
+                            else
+                                holes = intersection(holes, holes2);
+                        };
+                        auto combine_shells = [&shell](const Polygons &shells2) {
+                            if (shell.empty())
+                                shell = std::move(shells2);
+                            else if (! shells2.empty()) {
+                                polygons_append(shell, shells2);
+                                // Running the union_ using the Clipper library piece by piece is cheaper
+                                // than running the union_ all at once.
+                                shell = union_(shell);
+                            }
+                        };
+                        static constexpr const bool one_more_layer_below_top_bottom_surfaces = false;
+    			        if (int n_top_layers = region_config.top_shell_layers.value; n_top_layers > 0) {
+                            // Gather top regions projected to this layer.
+                            coordf_t print_z = layer->print_z;
+                            int i = int(idx_layer) + 1;
+                            int itop = int(idx_layer) + n_top_layers;
+                            bool at_least_one_top_projected = false;
+    	                    for (; i < int(cache_top_botom_regions.size()) &&
+    	                         (i < itop || m_layers[i]->print_z - print_z < region_config.top_shell_thickness - EPSILON);
+    	                        ++ i) {
+                                at_least_one_top_projected = true;
+    	                        const DiscoverVerticalShellsCacheEntry &cache = cache_top_botom_regions[i];
+                                combine_holes(cache.holes);
+                                combine_shells(cache.top_surfaces);
+    	                    }
+                            if (!at_least_one_top_projected && i < int(cache_top_botom_regions.size())) {
+                                // Lets consider this a special case - with only 1 top solid and minimal shell thickness settings, the
+                                // boundaries of solid layers are not anchored over/under perimeters, so lets fix it by adding at least one
+                                // perimeter width of area
+                                Polygons anchor_area = intersection(expand(cache_top_botom_regions[idx_layer].top_surfaces,
+                                                                           layerm->flow(frExternalPerimeter).scaled_spacing()),
+                                                                    to_polygons(m_layers[i]->lslices));
+                                combine_shells(anchor_area);
+                            }
+
+                            if (one_more_layer_below_top_bottom_surfaces)
+                                if (i < int(cache_top_botom_regions.size()) &&
+                                    (i <= itop || m_layers[i]->bottom_z() - print_z < region_config.top_shell_thickness - EPSILON))
+                                    combine_holes(cache_top_botom_regions[i].holes);
+    	                }
+    	                if (int n_bottom_layers = region_config.bottom_shell_layers.value; n_bottom_layers > 0) {
+                            // Gather bottom regions projected to this layer.
+                            coordf_t bottom_z = layer->bottom_z();
+                            int i = int(idx_layer) - 1;
+                            int ibottom = int(idx_layer) - n_bottom_layers;
+                            bool at_least_one_bottom_projected = false;
+    	                    for (; i >= 0 &&
+    	                         (i > ibottom || bottom_z - m_layers[i]->bottom_z() < region_config.bottom_shell_thickness - EPSILON);
+    	                        -- i) {
+                                    at_least_one_bottom_projected = true;
+    	                        const DiscoverVerticalShellsCacheEntry &cache = cache_top_botom_regions[i];
+    							combine_holes(cache.holes);
+                                combine_shells(cache.bottom_surfaces);
+    	                    }
+
+                            if (!at_least_one_bottom_projected && i >= 0) {
+                                Polygons anchor_area = intersection(expand(cache_top_botom_regions[idx_layer].bottom_surfaces,
+                                                                           layerm->flow(frExternalPerimeter).scaled_spacing()),
+                                                                    to_polygons(m_layers[i]->lslices));
+                                combine_shells(anchor_area);
+                            }
+
+                            if (one_more_layer_below_top_bottom_surfaces)
+                                if (i >= 0 &&
+                                    (i > ibottom || bottom_z - m_layers[i]->print_z < region_config.bottom_shell_thickness - EPSILON))
+                                    combine_holes(cache_top_botom_regions[i].holes);
+    	                }
+    };
+    std::vector<std::vector<ShellAccumulation>> shell_accumulations(top_bottom_surfaces_all_regions ? num_layers : 0);
+    if (! shell_accumulations.empty()) {
+        // Every (layer, key) pair is accumulated once, before the regions, so that nothing in the loop below is shared
+        // between them and they can run next to each other.
+        std::vector<std::array<size_t, 3>> todo; // layer, its slot, a region holding the key
+        for (size_t idx_layer = 0; idx_layer < num_layers; ++ idx_layer) {
+            std::vector<ShellAccumulation> &accumulations = shell_accumulations[idx_layer];
+            for (size_t region_id = 0; region_id < this->num_printing_regions(); ++ region_id) {
+                if (this->printing_region(region_id).config().ensure_vertical_shell_thickness.value != evstAll)
+                    continue;
+                const LayerRegion    *layerm = m_layers[idx_layer]->m_regions[region_id];
+                const AccumulationKey key    = accumulation_key(layerm->region().config(), layerm);
+                if (std::none_of(accumulations.begin(), accumulations.end(), [&key](const ShellAccumulation &a) { return a.key == key; })) {
+                    todo.push_back({ idx_layer, accumulations.size(), region_id });
+                    accumulations.push_back({ key, {}, {} });
+                }
+            }
+        }
+        tbb::parallel_for(size_t(0), todo.size(), [this, &todo, &shell_accumulations, &accumulate_shell](size_t i) {
+            m_print->throw_if_canceled();
+            const LayerRegion *layerm = m_layers[todo[i][0]]->m_regions[todo[i][2]];
+            ShellAccumulation &out    = shell_accumulations[todo[i][0]][todo[i][1]];
+            accumulate_shell(todo[i][0], layerm->region().config(), layerm, out.shell, out.holes);
+        });
+        m_print->throw_if_canceled();
+    }
+
+    const auto process_region = [&](size_t region_id) {
         const PrintRegion &region = this->printing_region(region_id);
         if (region.config().ensure_vertical_shell_thickness.value != evstAll )
             // This region will be handled by discover_horizontal_shells().
-            continue;
+            return;
 
         //FIXME Improve the heuristics for a grain size.
         size_t grain_size = std::max(num_layers / 16, size_t(1));
@@ -2348,7 +2497,7 @@ void PrintObject::discover_vertical_shells()
         grain_size = 1;
         tbb::parallel_for(
             tbb::blocked_range<size_t>(0, num_layers, grain_size),
-            [this, region_id, &cache_top_botom_regions]
+            [this, region_id, &shell_accumulations, &accumulation_key, &accumulate_shell]
             (const tbb::blocked_range<size_t>& range) {
                 // printf("discover_vertical_shells from %d to %d\n", range.begin(), range.end());
                 for (size_t idx_layer = range.begin(); idx_layer < range.end(); ++ idx_layer) {
@@ -2398,80 +2547,19 @@ void PrintObject::discover_vertical_shells()
                         }
                     }
 #endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
-			        polygons_append(holes, cache_top_botom_regions[idx_layer].holes);
-                    auto combine_holes = [&holes](const Polygons &holes2) {
-                        if (holes.empty() || holes2.empty())
-                            holes.clear();
-                        else
-                            holes = intersection(holes, holes2);
-                    };
-                    auto combine_shells = [&shell](const Polygons &shells2) {
-                        if (shell.empty())
-                            shell = std::move(shells2);
-                        else if (! shells2.empty()) {
-                            polygons_append(shell, shells2);
-                            // Running the union_ using the Clipper library piece by piece is cheaper
-                            // than running the union_ all at once.
-                            shell = union_(shell);
-                        }
-                    };
-                    static constexpr const bool one_more_layer_below_top_bottom_surfaces = false;
-			        if (int n_top_layers = region_config.top_shell_layers.value; n_top_layers > 0) {
-                        // Gather top regions projected to this layer.
-                        coordf_t print_z = layer->print_z;
-                        int i = int(idx_layer) + 1;
-                        int itop = int(idx_layer) + n_top_layers;
-                        bool at_least_one_top_projected = false;
-	                    for (; i < int(cache_top_botom_regions.size()) &&
-	                         (i < itop || m_layers[i]->print_z - print_z < region_config.top_shell_thickness - EPSILON);
-	                        ++ i) {
-                            at_least_one_top_projected = true;
-	                        const DiscoverVerticalShellsCacheEntry &cache = cache_top_botom_regions[i];
-                            combine_holes(cache.holes);
-                            combine_shells(cache.top_surfaces);
-	                    }
-                        if (!at_least_one_top_projected && i < int(cache_top_botom_regions.size())) {
-                            // Lets consider this a special case - with only 1 top solid and minimal shell thickness settings, the
-                            // boundaries of solid layers are not anchored over/under perimeters, so lets fix it by adding at least one
-                            // perimeter width of area
-                            Polygons anchor_area = intersection(expand(cache_top_botom_regions[idx_layer].top_surfaces,
-                                                                       layerm->flow(frExternalPerimeter).scaled_spacing()),
-                                                                to_polygons(m_layers[i]->lslices));
-                            combine_shells(anchor_area);
-                        }
-
-                        if (one_more_layer_below_top_bottom_surfaces)
-                            if (i < int(cache_top_botom_regions.size()) &&
-                                (i <= itop || m_layers[i]->bottom_z() - print_z < region_config.top_shell_thickness - EPSILON))
-                                combine_holes(cache_top_botom_regions[i].holes);
-	                }
-	                if (int n_bottom_layers = region_config.bottom_shell_layers.value; n_bottom_layers > 0) {
-                        // Gather bottom regions projected to this layer.
-                        coordf_t bottom_z = layer->bottom_z();
-                        int i = int(idx_layer) - 1;
-                        int ibottom = int(idx_layer) - n_bottom_layers;
-                        bool at_least_one_bottom_projected = false;
-	                    for (; i >= 0 &&
-	                         (i > ibottom || bottom_z - m_layers[i]->bottom_z() < region_config.bottom_shell_thickness - EPSILON);
-	                        -- i) {
-                                at_least_one_bottom_projected = true;
-	                        const DiscoverVerticalShellsCacheEntry &cache = cache_top_botom_regions[i];
-							combine_holes(cache.holes);
-                            combine_shells(cache.bottom_surfaces);
-	                    }
-
-                        if (!at_least_one_bottom_projected && i >= 0) {
-                            Polygons anchor_area = intersection(expand(cache_top_botom_regions[idx_layer].bottom_surfaces,
-                                                                       layerm->flow(frExternalPerimeter).scaled_spacing()),
-                                                                to_polygons(m_layers[i]->lslices));
-                            combine_shells(anchor_area);
-                        }
-
-                        if (one_more_layer_below_top_bottom_surfaces)
-                            if (i >= 0 &&
-                                (i > ibottom || bottom_z - m_layers[i]->print_z < region_config.bottom_shell_thickness - EPSILON))
-                                combine_holes(cache_top_botom_regions[i].holes);
-	                }
+                    const AccumulationKey key = accumulation_key(region_config, layerm);
+                    const ShellAccumulation *reused = shell_accumulations.empty() ? nullptr :
+                        [&]() -> const ShellAccumulation * {
+                            for (const ShellAccumulation &a : shell_accumulations[idx_layer])
+                                if (a.key == key)
+                                    return &a;
+                            return nullptr;
+                        }();
+                    if (reused != nullptr) {
+                        shell = reused->shell;
+                        holes = reused->holes;
+                    } else
+                        accumulate_shell(idx_layer, region_config, layerm, shell, holes);
 #ifdef SLIC3R_DEBUG_SLICE_PROCESSING
                     {
         				Slic3r::SVG svg(debug_out_path("discover_vertical_shells-perimeters-before-union-%d.svg", debug_idx), get_extents(shell));
@@ -2565,11 +2653,8 @@ void PrintObject::discover_vertical_shells()
                         Polygons object_volume;
                         Polygons internal_volume;
                         {
-                            Polygons shrinked_bottom_slice = idx_layer > 0 ? to_polygons(m_layers[idx_layer - 1]->lslices) : Polygons{};
-                            Polygons shrinked_upper_slice  = (idx_layer + 1) < m_layers.size() ?
-                                                                 to_polygons(m_layers[idx_layer + 1]->lslices) :
-                                                                 Polygons{};
-                            object_volume = intersection(shrinked_bottom_slice, shrinked_upper_slice);
+                            if (idx_layer > 0 && idx_layer + 1 < m_layers.size())
+                                object_volume = to_polygons(intersection_ex_by_piece(m_layers[idx_layer - 1]->lslices, to_polygons(m_layers[idx_layer + 1]->lslices)));
                             internal_volume = closing(polygonsInternal, SCALED_EPSILON);
                         }
 
@@ -2580,15 +2665,34 @@ void PrintObject::discover_vertical_shells()
                         //      the in-model condition is there due to small sloping surfaces, e.g. top of the hull of the benchy
                         //   2. the area does not fully cover an internal polygon
                         //         This is there mainly for a very thin parts, where the solid layers would be missing if the part area is quite small
+                        // Both tests below compare a small piece against the whole layer. Done literally, that is
+                        // quadratic in the number of pieces, which is what a layer split up by colour painting has,
+                        // so each is restricted to the part of the layer near the piece with an identical result:
+                        // object_volume is clipped to the piece's box, and only the internal polygons whose box meets
+                        // the expanded piece take part in the count, since the others pass through the difference
+                        // unchanged and add the same number to both sides of it.
+                        std::vector<BoundingBox> internal_bboxes;
+                        internal_bboxes.reserve(internal_volume.size());
+                        for (const Polygon &poly : internal_volume)
+                            internal_bboxes.emplace_back(get_extents(poly));
                         regularized_shell.erase(std::remove_if(regularized_shell.begin(), regularized_shell.end(),
-                                                               [&internal_volume, &min_perimeter_infill_spacing,
+                                                               [&internal_volume, &internal_bboxes, &min_perimeter_infill_spacing,
                                                                 &object_volume](const ExPolygon &p) {
-                                                                   return (p.area() < min_perimeter_infill_spacing * scaled(1.5) ||
-                                                                           (p.area() < min_perimeter_infill_spacing * scaled(8.0) &&
-                                                                            diff(to_polygons(p), object_volume).empty())) &&
-                                                                          diff(internal_volume,
-                                                                               expand(to_polygons(p), min_perimeter_infill_spacing))
-                                                                                  .size() >= internal_volume.size();
+                                                                   const bool small = p.area() < min_perimeter_infill_spacing * scaled(1.5) ||
+                                                                                      (p.area() < min_perimeter_infill_spacing * scaled(8.0) &&
+                                                                                       diff(to_polygons(p),
+                                                                                            ClipperUtils::clip_clipper_polygons_with_subject_bbox(
+                                                                                                object_volume, get_extents(p).inflated(SCALED_EPSILON)))
+                                                                                           .empty());
+                                                                   if (!small)
+                                                                       return false;
+                                                                   const Polygons    expanded = expand(to_polygons(p), min_perimeter_infill_spacing);
+                                                                   const BoundingBox bbox     = get_extents(expanded);
+                                                                   Polygons          nearby;
+                                                                   for (size_t i = 0; i < internal_volume.size(); ++i)
+                                                                       if (internal_bboxes[i].overlap(bbox))
+                                                                           nearby.emplace_back(internal_volume[i]);
+                                                                   return diff(nearby, expanded).size() >= nearby.size();
                                                                }),
                                                 regularized_shell.end());
                     }
@@ -2610,8 +2714,9 @@ void PrintObject::discover_vertical_shells()
 #endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
 
                     // Trim the internal & internalvoid by the shell.
-                    Slic3r::ExPolygons new_internal = diff_ex(layerm->fill_surfaces.filter_by_type(stInternal), regularized_shell);
-                    Slic3r::ExPolygons new_internal_void = diff_ex(layerm->fill_surfaces.filter_by_type(stInternalVoid), regularized_shell);
+                    const Polygons     regularized_shell_polygons = to_polygons(regularized_shell);
+                    Slic3r::ExPolygons new_internal = diff_ex_by_piece(to_expolygons(layerm->fill_surfaces.filter_by_type(stInternal)), regularized_shell_polygons);
+                    Slic3r::ExPolygons new_internal_void = diff_ex_by_piece(to_expolygons(layerm->fill_surfaces.filter_by_type(stInternalVoid)), regularized_shell_polygons);
 
 #ifdef SLIC3R_DEBUG_SLICE_PROCESSING
                     {
@@ -2638,7 +2743,15 @@ void PrintObject::discover_vertical_shells()
 			layerm->export_region_fill_surfaces_to_svg_debug("3_discover_vertical_shells-final");
 		}
 #endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
-    } // for each region
+    }; // for each region
+    if (top_bottom_surfaces_all_regions)
+        // Nothing is shared between the regions, and a layer cut through a fine relief takes far longer than the others,
+        // so they run next to each other instead of one after another.
+        tbb::parallel_for(size_t(0), this->num_printing_regions(), process_region);
+    else
+        // Here every region fills the one top/bottom cache with its own surfaces first.
+        for (size_t region_id = 0; region_id < this->num_printing_regions(); ++ region_id)
+            process_region(region_id);
 } // void PrintObject::discover_vertical_shells()
 
 // #define DEBUG_BRIDGE_OVER_INFILL
@@ -3159,6 +3272,16 @@ void PrintObject::bridge_over_infill()
                 vertical_lines[i].b = Point{x, y_max};
             }
 
+            // The vertical lines only span the bridged area's x range, so anchors entirely outside it can never be
+            // hit. Leaving them out gives the same intersections without building a tree over the whole layer's
+            // boundary for every bridge.
+            const coord_t scan_x_min = bb_x.min.x();
+            const coord_t scan_x_max = bb_x.min.x() + coord_t(n_vlines) * scan_spacing;
+            anchors.erase(std::remove_if(anchors.begin(), anchors.end(),
+                                         [scan_x_min, scan_x_max](const Line &l) {
+                                             return std::max(l.a.x(), l.b.x()) < scan_x_min || std::min(l.a.x(), l.b.x()) > scan_x_max;
+                                         }),
+                          anchors.end());
             auto anchors_and_walls_tree = AABBTreeLines::LinesDistancer<Line>{std::move(anchors)};
             auto bridged_area_tree      = AABBTreeLines::LinesDistancer<Line>{to_lines(bridged_area)};
 
@@ -3403,28 +3526,63 @@ void PrintObject::bridge_over_infill()
 
                 std::vector<CandidateSurface> expanded_surfaces;
                 expanded_surfaces.reserve(surfaces_by_layer[lidx].size());
+                // The expanded fill boundary depends only on the bridging flow, and total_fill_area is not
+                // modified below, so build it once per spacing rather than once per candidate. A layer split
+                // into many candidates (e.g. by colour painting) otherwise repeats a layer-wide offset for each.
+                std::map<coord_t, Polylines> boundary_by_spacing;
+                // expansion_area is a clean, non-overlapping set, so uniting it with a bridge or cutting a bridge
+                // out of it only changes the polygons near that bridge. The rest are passed through untouched
+                // instead of being fed to ClipperLib with the whole layer again for every candidate.
+                // Not `near`/`far`: the Windows headers still define those as macros, and they expand to
+                // nothing, which turns the declaration below into an empty one.
+                const auto split_near = [](const Polygons &polys, const BoundingBox &bbox, Polygons &rest) {
+                    Polygons nearby;
+                    for (const Polygon &p : polys)
+                        (get_extents(p).overlap(bbox) ? nearby : rest).emplace_back(p);
+                    return nearby;
+                };
                 for (const CandidateSurface &candidate : surfaces_by_layer[lidx]) {
                     const auto &region_config = candidate.region->region().config();
                     const bool turning_pattern = region_config.sparse_infill_pattern == ipHilbertCurve ||
                                                  region_config.sparse_infill_pattern == ipOctagramSpiral;
                     const Flow &flow              = candidate.region->bridging_flow(frSolidInfill, true);
                     Polygons    area_to_be_bridge = expand(candidate.new_polys, flow.scaled_spacing());
-                    area_to_be_bridge             = intersection(area_to_be_bridge, deep_infill_area);
+                    // deep_infill_area and internal_unsupported_area cover the whole layer; only their part under
+                    // this candidate can change the results, so they are clipped to its box first.
+                    if (!area_to_be_bridge.empty())
+                        area_to_be_bridge = intersection(area_to_be_bridge,
+                                                         ClipperUtils::clip_clipper_polygons_with_subject_bbox(
+                                                             deep_infill_area, get_extents(area_to_be_bridge).inflated(SCALED_EPSILON)));
 
                     area_to_be_bridge.erase(std::remove_if(area_to_be_bridge.begin(), area_to_be_bridge.end(),
-                                                           [internal_unsupported_area](const Polygon &p) {
-                                                               return intersection({p}, internal_unsupported_area).empty();
+                                                           [&internal_unsupported_area](const Polygon &p) {
+                                                               return intersection({p}, ClipperUtils::clip_clipper_polygons_with_subject_bbox(
+                                                                                            internal_unsupported_area,
+                                                                                            get_extents(p).inflated(SCALED_EPSILON)))
+                                                                   .empty();
                                                            }),
                                             area_to_be_bridge.end());
 
-                    Polygons limiting_area = union_(area_to_be_bridge, expansion_area);
-
                     if (area_to_be_bridge.empty())
                         continue;
 
-                    Polylines boundary_plines = to_polylines(expand(total_fill_area, 1.3 * flow.scaled_spacing()));
+                    Polygons       limiting_area;
+                    const Polygons near_expansion = split_near(expansion_area, get_extents(area_to_be_bridge).inflated(SCALED_EPSILON),
+                                                               limiting_area);
+                    append(limiting_area, union_(area_to_be_bridge, near_expansion));
+
+                    auto boundary_it = boundary_by_spacing.find(flow.scaled_spacing());
+                    if (boundary_it == boundary_by_spacing.end())
+                        boundary_it = boundary_by_spacing
+                                          .emplace(flow.scaled_spacing(), to_polylines(expand(total_fill_area, 1.3 * flow.scaled_spacing())))
+                                          .first;
+                    Polylines boundary_plines = boundary_it->second;
                     {
-                        Polylines limiting_plines = to_polylines(expand(limiting_area, 0.3*flow.spacing()));
+                        // No offset here: flow.spacing() is in mm, so the expand(limiting_area, 0.3 * flow.spacing())
+                        // this used to be moved the outline by 0.135 scaled units - nothing beyond rounding - while
+                        // costing a whole-layer ClipperLib pass for every candidate. limiting_area is already a clean
+                        // union, so its own outline is the same boundary.
+                        Polylines limiting_plines = to_polylines(limiting_area);
                         boundary_plines.insert(boundary_plines.end(), limiting_plines.begin(), limiting_plines.end());
                     }
 
@@ -3498,9 +3656,12 @@ void PrintObject::bridge_over_infill()
                     // Check collision with other expanded surfaces
                     {
                         bool     reconstruct       = false;
-                        Polygons tmp_expanded_area = expand(bridging_area, 3.0 * flow.scaled_spacing());
+                        Polygons          tmp_expanded_area = expand(bridging_area, 3.0 * flow.scaled_spacing());
+                        const BoundingBox tmp_expanded_bbox = get_extents(tmp_expanded_area);
                         for (const CandidateSurface &s : expanded_surfaces) {
-                            if (!intersection(s.new_polys, tmp_expanded_area).empty()) {
+                            // Surfaces whose boxes miss each other cannot intersect, which is most pairs on a busy layer.
+                            if (get_extents(s.new_polys).overlap(tmp_expanded_bbox) &&
+                                !intersection(s.new_polys, tmp_expanded_area).empty()) {
                                 bridging_angle = s.bridge_angle;
                                 reconstruct    = true;
                                 break;
@@ -3524,10 +3685,20 @@ void PrintObject::bridge_over_infill()
                         bridging_area = union_(bridging_area, construct_anchored_polygon(bridging_area, to_lines(boundary_plines), flow,
                                                                                        bridging_angle, scan_spacing, true));
                     }
-                    bridging_area          = intersection(bridging_area, limiting_area);
-                    bridging_area          = intersection(bridging_area, total_fill_area);
-                    bridging_area          = diff(bridging_area, total_top_area);
-                    expansion_area         = diff(expansion_area, bridging_area);
+                    // Each of these meets one bridge with the whole layer, so the layer side is first cut down to the
+                    // bridge's box (and expansion_area split as above); the result is the same.
+                    if (!bridging_area.empty()) {
+                        const BoundingBox bridging_bbox = get_extents(bridging_area).inflated(SCALED_EPSILON);
+                        bridging_area = intersection(bridging_area, ClipperUtils::clip_clipper_polygons_with_subject_bbox(limiting_area, bridging_bbox));
+                        bridging_area = intersection(bridging_area, ClipperUtils::clip_clipper_polygons_with_subject_bbox(total_fill_area, bridging_bbox));
+                        bridging_area = diff(bridging_area, ClipperUtils::clip_clipper_polygons_with_subject_bbox(total_top_area, bridging_bbox));
+                    }
+                    if (!bridging_area.empty()) {
+                        Polygons       kept;
+                        const Polygons cut = split_near(expansion_area, get_extents(bridging_area).inflated(SCALED_EPSILON), kept);
+                        append(kept, diff(cut, bridging_area));
+                        expansion_area = std::move(kept);
+                    }
 
 #ifdef DEBUG_BRIDGE_OVER_INFILL
                     debug_draw(std::to_string(lidx) + "_" + std::to_string(cluster_idx) + "_" + std::to_string(job_idx) + "_" + "_expanded_bridging" +  std::to_string(r),

src/libslic3r/Support/SupportMaterial.cpp

@@ -929,9 +929,9 @@ public:
                 ::fread(&y, sizeof(coord_t), 1, file);
                 poly.points.emplace_back(Point(x * scale, y * scale));
             }
+            printf("Polygon %d, area: %lf\n", i, area(poly.points));
             if (which == -1 || which == i)
                 m_support_polygons_deserialized.emplace_back(std::move(poly));
-            printf("Polygon %d, area: %lf\n", i, area(poly.points));
         }
         ::fread(&n_polygons, 4, 1, file);
         m_trimming_polygons_deserialized.reserve(n_polygons);

src/libslic3r/Support/TreeSupport.cpp

@@ -854,11 +854,41 @@ void TreeSupport::detect_overhangs(bool check_support_necessity/* = false*/)
                 if (is_auto(stype) && config_detect_sharp_tails)
                 {
                     // BBS detect sharp tail
+                    // Each island is tested only against the lower islands whose box meets its own: overlaps() tries every
+                    // pair, which on a layer cut through a fine relief (thousands of islands above thousands) never ends.
+                    std::vector<BoundingBox> lower_bboxes;
+                    lower_bboxes.reserve(lower_polys.size());
+                    for (const ExPolygon &lower : lower_polys)
+                        lower_bboxes.emplace_back(get_extents(lower));
                     for (const ExPolygon& expoly : curr_polys) {
                         bool  is_sharp_tail = false;
                         // 1. nothing below
                         // this is a sharp tail region if it's floating and non-ignorable
-                        if (!overlaps(offset_ex(expoly, 0.1 * extrusion_width_scaled), lower_polys)) {
+                        const ExPolygons  expanded = offset_ex(expoly, 0.1 * extrusion_width_scaled);
+                        const BoundingBox bbox     = get_extents(expanded);
+                        ExPolygons        lower_nearby;
+                        for (size_t i = 0; i < lower_polys.size(); ++i)
+                            if (lower_bboxes[i].overlap(bbox))
+                                lower_nearby.emplace_back(lower_polys[i]);
+                        // As overlaps(expanded, lower_nearby), with each lower island cut to the island's box first: below
+                        // a fine relief the lower layer is a few islands with thousands of holes, whose whole boundary
+                        // was otherwise intersected again for every island above.
+                        const auto overlaps_nearby = [&]() {
+                            for (const ExPolygon &a : expanded) {
+                                if (a.empty())
+                                    continue;
+                                const BoundingBox a_bbox = get_extents(a);
+                                for (const ExPolygon &b : lower_nearby) {
+                                    if (b.empty() || !get_extents(b).overlap(a_bbox))
+                                        continue;
+                                    const Polygons b_near = ClipperUtils::clip_clipper_polygons_with_subject_bbox(b, a_bbox.inflated(SCALED_EPSILON));
+                                    if (!intersection_pl(to_polylines(b_near), a).empty() || b.contains(a.contour.points.front()))
+                                        return true;
+                                }
+                            }
+                            return false;
+                        };
+                        if (!overlaps_nearby()) {
                             is_sharp_tail = !offset_ex(expoly, -0.1 * extrusion_width_scaled).empty();
                         }
 

src/libslic3r/Surface.hpp

@@ -61,7 +61,7 @@ public:
             thickness(other.thickness), thickness_layers(other.thickness_layers),
             bridge_angle(other.bridge_angle), extra_perimeters(other.extra_perimeters)
         {};
-    Surface(Surface &&rhs)
+    Surface(Surface &&rhs) noexcept
         : surface_type(rhs.surface_type), expolygon(std::move(rhs.expolygon)),
             thickness(rhs.thickness), thickness_layers(rhs.thickness_layers),
             bridge_angle(rhs.bridge_angle), extra_perimeters(rhs.extra_perimeters)
@@ -87,7 +87,7 @@ public:
         return *this;
     }
 
-    Surface& operator=(Surface &&rhs)
+    Surface& operator=(Surface &&rhs) noexcept
     {
         surface_type     = rhs.surface_type;
         expolygon        = std::move(rhs.expolygon);

src/libslic3r/Utils.hpp

@@ -8,8 +8,6 @@
 #include <functional>
 #include <type_traits>
 #include <system_error>
-#include <initializer_list>
-#include <string_view>
 #include <regex>
 
 #include <boost/system/error_code.hpp>
@@ -226,21 +224,6 @@ extern std::vector<std::string> split_string(const std::string &str, char delimi
 // On Windows, the file explorer (or anti-virus or whatever else) often locks the file
 // for a short while, so the file may not be movable. Retry while we see recoverable errors.
 extern std::error_code rename_file(const std::string &from, const std::string &to);
-// Write `chunks`, in order, to `path` through a temporary file beside it that is
-// then renamed over the target, so a concurrent reader sees the old or the new
-// file, never a partial one. The temporary is removed on failure and an existing
-// target keeps its permissions. Text mode unless `binary`, so Windows writes CRLF
-// as the streams this replaces did. A target that is not a regular file (a
-// device or pipe) is written in place, since replacing it would change what it
-// is, and so is an existing target beside which no temporary can be created or
-// whose replace the filesystem refuses; a symlink is followed and the file it
-// names is replaced. On Windows a reader holding the
-// target open without sharing its deletion, which the C runtime does not, makes
-// the replace fall back to the in-place write too, so an unlocked reader there
-// can still see a partial file.
-extern std::error_code write_file_atomically(const std::string &path, std::initializer_list<std::string_view> chunks, bool binary = false);
-inline std::error_code write_file_atomically(const std::string &path, const std::string &content, bool binary = false)
-	{ return write_file_atomically(path, { std::string_view(content) }, binary); }
 
 enum CopyFileResult {
 	SUCCESS = 0,

src/libslic3r/libslic3r.h

@@ -162,10 +162,10 @@ inline void append(std::vector<T, Alloc> &dest, std::vector<T, Alloc> &&src)
 {
     if (dest.empty())
         dest = std::move(src);
-    else {
-        dest.reserve(dest.size() + src.size());
-        std::move(std::begin(src), std::end(src), std::back_inserter(dest));
-    }
+    else
+        // insert() grows the capacity geometrically; reserving exactly the new size reallocated on every call, which
+        // made appending piece by piece quadratic.
+        dest.insert(dest.end(), std::make_move_iterator(src.begin()), std::make_move_iterator(src.end()));
     src.clear();
     src.shrink_to_fit();
 }

src/libslic3r/utils.cpp

@@ -9,8 +9,6 @@
 #include <stdio.h>
 #include <filesystem>
 #include <sstream>
-#include <cerrno>
-#include <mutex>
 #include <iomanip>
 #include <algorithm>
 #include <cmath>
@@ -704,99 +702,13 @@ namespace WindowsSupport
 std::error_code rename_file(const std::string &from, const std::string &to)
 {
 #ifdef _WIN32
-	// Retries and moves an open destination aside itself.
 	return WindowsSupport::rename(from, to);
 #else
-	// rename(2) replaces an existing target atomically; removing it first would
-	// leave a window in which the file does not exist at all.
-	if (boost::nowide::rename(from.c_str(), to.c_str()) == 0)
-		return {};
-	const int err = errno;
-	// Some mounts (sshfs, gvfs, MTP and a few SMB setups) refuse to replace an
-	// existing target in one step, each with the error it sees fit; every error
-	// is worth the remove-then-rename this always did, except the ones no retry
-	// can help: nothing at the source, a different device, or a directory where
-	// a file was expected and the reverse.
-	const bool worth_retrying = err != ENOENT && err != EXDEV && err != ENOTDIR && err != EISDIR;
-	if (worth_retrying && boost::nowide::remove(to.c_str()) == 0 && boost::nowide::rename(from.c_str(), to.c_str()) == 0)
-		return {};
-	return std::make_error_code(static_cast<std::errc>(err));
+	boost::nowide::remove(to.c_str());
+	return std::make_error_code(static_cast<std::errc>(boost::nowide::rename(from.c_str(), to.c_str())));
 #endif
 }
 
-static std::error_code write_whole_file(const std::string &path, std::initializer_list<std::string_view> chunks, bool binary)
-{
-	errno = 0;
-	FILE *file = boost::nowide::fopen(path.c_str(), binary ? "wb" : "w");
-	if (file == nullptr)
-		return std::make_error_code(errno != 0 ? static_cast<std::errc>(errno) : std::errc::io_error);
-	bool ok = true;
-	for (const std::string_view chunk : chunks)
-		ok = ok && std::fwrite(chunk.data(), 1, chunk.size(), file) == chunk.size();
-	ok = ok && std::fflush(file) == 0;
-	const int err = ok ? 0 : errno;
-	ok = std::fclose(file) == 0 && ok;
-	if (ok)
-		return {};
-	return std::make_error_code(err != 0 ? static_cast<std::errc>(err) : std::errc::io_error);
-}
-
-// The in-place fallback truncates the target, so two threads of this process
-// on the same file must not both be in it. One mutex for all such writes: they
-// are the rare case. Never freed, like the InstanceLock registry, so a save
-// during static destruction still finds it.
-static std::error_code write_in_place(const std::string &path, std::initializer_list<std::string_view> chunks, bool binary)
-{
-	static auto *mutex = new std::mutex();
-	std::lock_guard<std::mutex> guard(*mutex);
-	return write_whole_file(path, chunks, binary);
-}
-
-std::error_code write_file_atomically(const std::string &path, std::initializer_list<std::string_view> chunks, bool binary)
-{
-	boost::system::error_code bec;
-	const boost::filesystem::file_status target = boost::filesystem::symlink_status(path, bec);
-	const bool target_exists = ! bec && boost::filesystem::exists(target);
-	if (target_exists && boost::filesystem::is_symlink(target)) {
-		// A config or preset kept in a dotfiles repository: the link stays,
-		// the file it points to is replaced like any other.
-		const boost::filesystem::path resolved = boost::filesystem::canonical(path, bec);
-		if (! bec && boost::filesystem::is_regular_file(resolved, bec))
-			return write_file_atomically(resolved.string(), chunks, binary);
-	}
-	if (target_exists && ! boost::filesystem::is_regular_file(target))
-		return write_in_place(path, chunks, binary);
-
-	// Unique per process and per call, so two threads writing one target
-	// without a lock never share a temporary.
-	static std::atomic<unsigned> counter{0};
-	const std::string tmp_path = path + "." + std::to_string(get_current_pid()) + "." + std::to_string(counter++) + ".tmp";
-	if (const std::error_code ec = write_whole_file(tmp_path, chunks, binary)) {
-		boost::nowide::remove(tmp_path.c_str());
-		if (! target_exists)
-			return ec;
-		// A directory that lets this process write its files but not create
-		// one: losing the save is worse than a reader seeing a partial file.
-		BOOST_LOG_TRIVIAL(warning) << "Cannot create a temporary beside " << path << " (" << ec.message() << "); writing in place";
-		return write_in_place(path, chunks, binary);
-	}
-#ifndef _WIN32
-	// Not on Windows, where a read-only bit on the temporary would stop the rename itself.
-	if (target_exists)
-		boost::filesystem::permissions(tmp_path, target.permissions(), bec);
-#endif
-	if (const std::error_code ec = rename_file(tmp_path, path)) {
-		boost::nowide::remove(tmp_path.c_str());
-		// A reader on Windows holding the target open without FILE_SHARE_DELETE,
-		// or a mount that cannot replace a file at all. Losing the save is worse
-		// than a reader seeing a partial file, so write in place the way this
-		// used to work before the atomic path existed.
-		BOOST_LOG_TRIVIAL(warning) << "Cannot replace " << path << " (" << ec.message() << "); writing in place";
-		return write_in_place(path, chunks, binary);
-	}
-	return {};
-}
-
 #ifdef __linux__
 // Copied from boost::filesystem.
 // Called by copy_file_linux() in case linux sendfile() API is not supported.

src/slic3r/GUI/GUI_App.cpp

@@ -85,7 +85,6 @@
 #include "libslic3r/Model.hpp"
 #include "libslic3r/I18N.hpp"
 #include "libslic3r/PresetBundle.hpp"
-#include "libslic3r/InstanceLock.hpp"
 #include "libslic3r/Thread.hpp"
 #include "libslic3r/miniz_extension.hpp"
 #include "libslic3r/Utils.hpp"
@@ -3550,7 +3549,7 @@ bool GUI_App::on_init_inner()
             update_publish_status();
         }
 
-        if (m_post_initialized && app_config->dirty() && app_config->save_due())
+        if (m_post_initialized && app_config->dirty())
             app_config->save();
 
     });
@@ -7644,11 +7643,8 @@ void GUI_App::start_sync_user_preset(bool with_progress_dlg)
 
                             // Delete the bundle folder and bundle
                             fs::path bundle_folder = fs::path(bundle.path.c_str()).parent_path();
-                            {
-                                boost::system::error_code ec;
-                                InstanceLock instance_lock(user_presets_lock_path());
-                                boost::filesystem::remove_all(bundle_folder, ec);
-                            }
+                            boost::system::error_code ec;
+                            boost::filesystem::remove_all(bundle_folder, ec);
 
                             preset_bundle->bundles.WriteLock();
                             preset_bundle->bundles.m_bundles.erase(bundle.id);
@@ -8935,7 +8931,6 @@ void GUI_App::preset_deleted_from_cloud(std::string setting_id)
 
     // Delete the .info file after cloud deletion is confirmed
     if (!preset_file_path.empty() && fs::exists(fs::path(preset_file_path))) {
-        InstanceLock instance_lock(user_presets_lock_path());
         boost::nowide::remove(preset_file_path.c_str());
         BOOST_LOG_TRIVIAL(info) << "Deleted .info file after cloud confirmation: " << preset_file_path;
     }
@@ -8998,19 +8993,15 @@ void GUI_App::scan_orphaned_info_files()
             fs::path preset_file = info_file;
             preset_file.replace_extension(".json");
 
-            // If .json doesn't exist, .info is orphaned. Read under the lock, so a
-            // remove_files() in another instance is seen whole or not at all; the
-            // delete queue's own mutex is taken after the lock is released.
-            std::string setting_id;
-            {
-                InstanceLock instance_lock(user_presets_lock_path());
-                if (!fs::exists(preset_file))
-                    setting_id = extract_setting_id_from_info(info_file.string());
-            }
-            if (!setting_id.empty()) {
-                // Add to need_delete_presets
-                delete_preset_from_cloud(setting_id, info_file.string());
-                BOOST_LOG_TRIVIAL(info) << "Found orphaned .info file on startup: " << info_file.string();
+            // If .json doesn't exist, .info is orphaned
+            if (!fs::exists(preset_file)) {
+                // Extract setting_id from .info file
+                std::string setting_id = extract_setting_id_from_info(info_file.string());
+                if (!setting_id.empty()) {
+                    // Add to need_delete_presets
+                    delete_preset_from_cloud(setting_id, info_file.string());
+                    BOOST_LOG_TRIVIAL(info) << "Found orphaned .info file on startup: " << info_file.string();
+                }
             }
         }
         if (ec)

src/slic3r/GUI/WebGuideDialog.cpp

@@ -1405,26 +1405,23 @@ bool GuideFrame::BuildProfileDataFromVendors()
         // is served from the shipped profiles. Each is stamped by name and
         // version alone: a profile change requires a version bump, so those two
         // determine content wherever the vendor's copy sits.
-        std::vector<PresetBundle::VendorSource> ordered;
-        json stamps = json::array();
-        auto add_vendor = [&ordered, &stamps](const std::string& name, const boost::filesystem::path& dir) {
+        struct VendorSource { std::string name; boost::filesystem::path dir; std::string version; };
+        std::vector<VendorSource> ordered;
+        auto add_vendor = [&ordered](const std::string& name, const boost::filesystem::path& dir) {
             // The version a load from `dir` would serve: the profile's where one
             // exists (a cache is only served while it covers the profile beside
             // it), the cache's own stamp where the cache is the whole vendor.
             // A profile without a version (blacklist.json) carries no presets
             // and is passed over.
             const boost::filesystem::path profile = dir / (name + ".json");
-            std::string version;
             if (boost::filesystem::exists(profile)) {
                 const Semver v = get_version_from_json(profile.string());
-                if (! v.valid())
-                    return;
-                version = v.to_string();
+                if (v.valid())
+                    ordered.push_back({name, dir, v.to_string()});
             } else {
-                version = VendorCacheFile::peek_version((dir / (name + ".opc")).string(), name);
+                ordered.push_back({name, dir,
+                    VendorCacheFile::peek_version((dir / (name + ".opc")).string(), name)});
             }
-            ordered.push_back({name, dir});
-            stamps.push_back({name, version});
         };
         const std::string filament_library(PresetBundle::ORCA_FILAMENT_LIBRARY);
         if (auto it = vendor_sources.find(filament_library); it != vendor_sources.end())
@@ -1434,6 +1431,9 @@ bool GuideFrame::BuildProfileDataFromVendors()
                 add_vendor(name, dir);
         if (ordered.empty())
             return false;
+        json stamps = json::array();
+        for (const VendorSource& v : ordered)
+            stamps.push_back({v.name, v.version});
 
         // What this function derives is a pure function of that stamped set, so
         // the derived JSON is cached whole: a fresh cache makes an open one
@@ -1461,24 +1461,34 @@ bool GuideFrame::BuildProfileDataFromVendors()
         }
 
         // Each vendor comes from its preset cache where one covers it, which is
-        // what makes this worth doing instead of the scan below.
-        PresetBundle             bundle;
-        std::vector<std::string> failed;
-        const std::string errors = bundle.load_vendors(ordered, ForwardCompatibilitySubstitutionRule::EnableSilent,
-                                                       /*allow_cache=*/true, m_cancel_token.get(), &failed).second;
-        if (*m_cancel_token || bundle.vendors.empty())
-            return false;
-        if (! errors.empty())
-            BOOST_LOG_TRIVIAL(warning) << "GuideFrame: loading the vendors reported: " << errors;
-        // A vendor that failed to load sends this open to the scan below, which lists
-        // what it can read of every vendor.
-        if (! failed.empty())
+        // what makes this worth doing instead of the scan below; loading into a
+        // bundle per vendor keeps the install order the startup path has.
+        PresetBundle bundle;
+        auto load_vendor = [](PresetBundle& into, const std::string& vendor,
+                              const boost::filesystem::path& dir, const PresetBundle* base) {
+            into.load_vendor_configs_from_json(dir.string(), vendor, PresetBundle::LoadSystem,
+                                               ForwardCompatibilitySubstitutionRule::EnableSilent, base);
+        };
+        for (const VendorSource& v : ordered) {
+            if (*m_cancel_token)
+                return false;   // as in the scan below: a vendor without a cache is parsed, and that takes time
+            if (v.name == filament_library) {
+                load_vendor(bundle, v.name, v.dir, nullptr);
+            } else {
+                PresetBundle tmp;
+                load_vendor(tmp, v.name, v.dir, &bundle);
+                bundle.merge_presets(std::move(tmp));
+            }
+        }
+        if (bundle.vendors.empty())
             return false;
         if (! BuildProfileJson(bundle, /*require_all_resource_vendors=*/false))
             return false;
 
         // Written through a temp file and moved into place, as the preset caches
-        // are: half a cache must never be readable.
+        // are: half a cache must never be readable, and the PID suffix keeps two
+        // instances from interleaving on one temp file.
+        const std::string tmp_path = cache_file.string() + "." + std::to_string(get_current_pid()) + ".tmp";
         try {
             json out;
             out["format"]  = 1;
@@ -1487,9 +1497,18 @@ bool GuideFrame::BuildProfileDataFromVendors()
             for (const char* key : { "model", "machine", "filament", "process" })
                 profile[key] = m_ProfileJson[key];
             boost::filesystem::create_directories(cache_file.parent_path());
-            if (const std::error_code ec = write_file_atomically(cache_file.string(), out.dump(-1, ' ', false, json::error_handler_t::ignore), /*binary=*/true))
+            {
+                boost::nowide::ofstream ofs(tmp_path, std::ios::binary | std::ios::trunc);
+                ofs << out.dump(-1, ' ', false, json::error_handler_t::ignore);
+                ofs.close();
+                if (! ofs.good())
+                    throw std::runtime_error("write failed");
+            }
+            if (const std::error_code ec = rename_file(tmp_path, cache_file.string()))
                 throw std::runtime_error(ec.message());
         } catch (const std::exception& e) {
+            boost::system::error_code rm;
+            boost::filesystem::remove(tmp_path, rm);
             BOOST_LOG_TRIVIAL(warning) << "GuideFrame: could not write the profile data cache: " << e.what();
         }
         return true;

src/slic3r/Utils/3DPrinterOS.cpp

@@ -2,7 +2,6 @@
 
 #include <algorithm>
 #include <sstream>
-#include <system_error>
 #include <exception>
 #include <boost/format.hpp>
 #include <boost/log/trivial.hpp>
@@ -581,10 +580,9 @@ bool C3DPrinterOS::save_api_session(const std::string &session, const std::strin
     j.put("session", session);
     j.put("email", email);
     try {
-        std::ostringstream json;
-        pt::write_json(json, j);
-        if (const std::error_code ec = write_file_atomically(m_api_session_file_path, json.str()))
-            throw std::system_error(ec);
+        auto temp_path = m_api_session_file_path + ".tmp";
+        pt::write_json(temp_path, j);
+        boost::filesystem::rename(temp_path, m_api_session_file_path);
     } catch (const std::exception &err) {
         BOOST_LOG_TRIVIAL(error) << __FUNCTION__ << ": failed to write json to file. Path = "
                                  << m_api_session_file_path

src/slic3r/Utils/OrcaCloudServiceAgent.cpp

@@ -1475,8 +1475,15 @@ void OrcaCloudServiceAgent::save_sync_state()
     if (sync_state_path.empty())
         return;
 
-    if (const std::error_code ec = write_file_atomically(sync_state_path, std::to_string(sync_state.last_sync_timestamp)))
-        BOOST_LOG_TRIVIAL(warning) << "OrcaCloudServiceAgent: failed to save the sync state: " << ec.message();
+    try {
+        std::string tmp_path = sync_state_path + ".tmp";
+        std::ofstream ofs(tmp_path, std::ios::out | std::ios::trunc);
+        if (ofs.good()) {
+            ofs << std::to_string(sync_state.last_sync_timestamp);
+            ofs.close();
+            boost::filesystem::rename(tmp_path, sync_state_path);
+        }
+    } catch (...) {}
 }
 
 void OrcaCloudServiceAgent::clear_sync_state()
@@ -1565,10 +1572,22 @@ void OrcaCloudServiceAgent::persist_user_secret(const std::string& secret)
             wxFileName::Mkdir(path.GetPath(), wxS_DIR_DEFAULT, wxPATH_MKDIR_FULL);
         }
 
-        if (const std::error_code ec = write_file_atomically(secret_fallback_path, signed_payload, /*binary=*/true))
-            BOOST_LOG_TRIVIAL(warning) << "OrcaCloudServiceAgent: cannot write user secret file " << secret_fallback_path << ": " << ec.message();
-        else
-            stored = true;
+        const std::string tmp_path = secret_fallback_path + ".tmp";
+        std::ofstream ofs(tmp_path, std::ios::out | std::ios::trunc | std::ios::binary);
+        if (ofs.good()) {
+            ofs << signed_payload;
+            ofs.flush();
+            ofs.close();
+
+            if (wxRenameFile(wxString::FromUTF8(tmp_path.c_str()), wxString::FromUTF8(secret_fallback_path.c_str()), true)) {
+                stored = true;
+            } else {
+                wxRemoveFile(wxString::FromUTF8(tmp_path.c_str()));
+                BOOST_LOG_TRIVIAL(warning) << "OrcaCloudServiceAgent: failed to atomically replace user secret file";
+            }
+        } else {
+            BOOST_LOG_TRIVIAL(warning) << "OrcaCloudServiceAgent: cannot open user secret file for write - " << secret_fallback_path;
+        }
     } else {
         // Use wxSecretStore only
         wxSecretStore store = wxSecretStore::GetDefault();

src/slic3r/plugin/PluginConfig.cpp

@@ -249,10 +249,21 @@ bool PluginConfig::save()
         return false;
     }
 
-    // Written beside the target and moved into place, so a crash mid-write cannot truncate an
-    // existing config.
-    if (const std::error_code ec = write_file_atomically(path, root.dump(1, '\t') + "\n")) {
-        BOOST_LOG_TRIVIAL(error) << "PluginConfig: failed to write " << path << ": " << ec.message() << "; keeping the existing config";
+    // Write to a PID-suffixed file and rename it into place, so a crash mid-write cannot truncate an
+    // existing config. Same approach as AppConfig::save().
+    const std::string path_pid = (boost::format("%1%.%2%") % path % get_current_pid()).str();
+
+    boost::nowide::ofstream file;
+    file.open(path_pid, std::ios::out | std::ios::trunc);
+    file << root.dump(1, '\t') << std::endl;
+    file.close();
+    if (file.fail()) {
+        BOOST_LOG_TRIVIAL(error) << "PluginConfig: failed to write " << path_pid << "; keeping the existing config";
+        return false;
+    }
+
+    if (const std::error_code rename_ec = rename_file(path_pid, path)) {
+        BOOST_LOG_TRIVIAL(error) << "PluginConfig: failed to move " << path_pid << " onto " << path << ": " << rename_ec.message();
         return false;
     }
 

tests/libslic3r/CMakeLists.txt

@@ -16,10 +16,8 @@ add_executable(${_TEST_NAME}_tests
     test_clipper_utils.cpp
     test_config.cpp
     test_config_variant_expansion.cpp
-    test_locales_utils.cpp
     test_drc.cpp
     test_toolordering_nozzle_group.cpp
-    test_parallel_resolve.cpp
     test_preset_bundle_loading.cpp
     test_preset_setting_id.cpp
     test_preset_diff.cpp
@@ -30,6 +28,7 @@ add_executable(${_TEST_NAME}_tests
     test_filament_mixer.cpp
     test_fill_plane_path.cpp
     test_geometry.cpp
+    test_kdtree.cpp
     test_multimaterial_segmentation.cpp
     test_placeholder_parser.cpp
     test_polygon.cpp
@@ -55,7 +54,6 @@ add_executable(${_TEST_NAME}_tests
     test_ordering_strategies.cpp
     # test_png_io.cpp
     test_indexed_triangle_set.cpp
-    test_instance_lock.cpp
     ../libnest2d/printer_parts.cpp
     )
 

tests/libslic3r/test_clipper_utils.cpp

@@ -299,3 +299,47 @@ TEST_CASE("Traversing Clipper PolyTree", "[ClipperUtils]") {
         REQUIRE(count_polys(output) == reference.size());
     }
 }
+
+TEST_CASE("Tiled diff and intersection cover the same area as the plain calls", "[ClipperUtils]") {
+    // A grid of disjoint framed squares, enough of them to be split into several tiles.
+    const int  n    = 40;
+    const coord_t cell = scaled<coord_t>(2.), side = scaled<coord_t>(1.5), frame = scaled<coord_t>(0.3);
+    ExPolygons subject;
+    for (int y = 0; y < n; ++ y)
+        for (int x = 0; x < n; ++ x) {
+            const Point o(x * cell, y * cell);
+            ExPolygon square(Polygon({ o, o + Point(side, 0), o + Point(side, side), o + Point(0, side) }));
+            Polygon hole({ o + Point(frame, frame), o + Point(frame, side - frame), o + Point(side - frame, side - frame), o + Point(side - frame, frame) });
+            square.holes.emplace_back(std::move(hole));
+            subject.emplace_back(std::move(square));
+        }
+    // Clip polygons crossing many squares, one of them large with holes of its own.
+    Polygons clip;
+    const coord_t span = n * cell;
+    for (int i = 0; i < 8; ++ i) {
+        const coord_t y0 = coord_t(i) * span / 8, y1 = y0 + scaled<coord_t>(0.9);
+        clip.emplace_back(Polygon({ Point(- cell, y0), Point(span, y0 + cell * 3), Point(span, y1 + cell * 3), Point(- cell, y1) }));
+    }
+    ExPolygon big(Polygon({ Point(span / 4, span / 4), Point(3 * span / 4, span / 4), Point(3 * span / 4, 3 * span / 4), Point(span / 4, 3 * span / 4) }));
+    for (int i = 0; i < 4; ++ i) {
+        const Point o(span / 4 + scaled<coord_t>(3.1) + i * scaled<coord_t>(9.7), span / 4 + scaled<coord_t>(5.3));
+        big.holes.emplace_back(Polygon({ o, o + Point(0, scaled<coord_t>(20.)), o + Point(scaled<coord_t>(5.), scaled<coord_t>(20.)), o + Point(scaled<coord_t>(5.), 0) }));
+    }
+    polygons_append(clip, to_polygons(big));
+
+    const auto xor_area = [](const ExPolygons &a, const ExPolygons &b) { return area(diff_ex(a, b)) + area(diff_ex(b, a)); };
+    const ApplySafetyOffset safety = GENERATE(ApplySafetyOffset::No, ApplySafetyOffset::Yes);
+    const double tolerance = double(scaled<coord_t>(0.001)) * double(span);
+
+    const ExPolygons diff_plain = diff_ex(subject, clip, safety);
+    const ExPolygons diff_tiled = diff_ex_by_piece(subject, clip, safety);
+    REQUIRE(area(diff_plain) > 0.);
+    CHECK_THAT(area(diff_tiled), Catch::Matchers::WithinRel(area(diff_plain), 1e-9));
+    CHECK(xor_area(diff_tiled, diff_plain) < tolerance);
+
+    const ExPolygons intersection_plain = intersection_ex(subject, clip, safety);
+    const ExPolygons intersection_tiled = intersection_ex_by_piece(subject, clip, safety);
+    REQUIRE(area(intersection_plain) > 0.);
+    CHECK_THAT(area(intersection_tiled), Catch::Matchers::WithinRel(area(intersection_plain), 1e-9));
+    CHECK(xor_area(intersection_tiled, intersection_plain) < tolerance);
+}

tests/libslic3r/test_instance_lock.cpp

@@ -1,228 +0,0 @@
-#include <catch2/catch_all.hpp>
-
-#include <atomic>
-#include <chrono>
-#include <thread>
-
-#include <boost/filesystem.hpp>
-
-#include "libslic3r/InstanceLock.hpp"
-#include "test_utils.hpp"
-
-#ifdef _WIN32
-#include <boost/interprocess/sync/file_lock.hpp>
-#include <boost/nowide/convert.hpp>
-#include <boost/nowide/fstream.hpp>
-#else
-#include <fcntl.h>
-#include <sys/file.h>
-#include <unistd.h>
-#endif
-
-using namespace Slic3r;
-using namespace std::chrono_literals;
-
-// Sets a process-wide knob for one test and restores it however the test ends.
-template<typename T> struct ScopedStaticValue
-{
-    T &ref;
-    T  saved;
-    ScopedStaticValue(T &ref, T value) : ref(ref), saved(ref) { ref = value; }
-    ~ScopedStaticValue() { ref = saved; }
-};
-
-TEST_CASE("InstanceLock creates its lock file and holds it for the guard's scope", "[InstanceLock]")
-{
-    ScopedTemporaryFile lock_file(".lock");
-    const std::string   path = lock_file.string();
-
-    {
-        InstanceLock lock(path);
-        REQUIRE(lock.locked());
-        REQUIRE(boost::filesystem::exists(path));
-    }
-    // Released: a fresh guard gets the lock at once instead of waiting out a timeout.
-    const auto   started = std::chrono::steady_clock::now();
-    InstanceLock again(path, 5000ms);
-    REQUIRE(again.locked());
-    // Well inside the timeout it would otherwise have waited out; loose enough for a loaded runner.
-    REQUIRE(std::chrono::steady_clock::now() - started < 4000ms);
-}
-
-TEST_CASE("InstanceLock nests within one thread", "[InstanceLock]")
-{
-    ScopedTemporaryFile lock_file(".lock");
-    const std::string   path = lock_file.string();
-
-    InstanceLock outer(path);
-    {
-        InstanceLock inner(path, 100ms);
-        REQUIRE(inner.locked());
-    }
-    // The inner guard leaving does not release the outer one.
-    REQUIRE(outer.locked());
-}
-
-TEST_CASE("InstanceLock is a no-op for an empty path and survives an unwritable one", "[InstanceLock]")
-{
-    ScopedTemporaryDir dir;
-
-    InstanceLock none("");
-    REQUIRE_FALSE(none.locked());
-
-    // The directory does not exist, so the lock file cannot be created; the
-    // guard still constructs and the write it guards can go ahead.
-    InstanceLock unwritable((dir.path() / "missing" / "shared.lock").string(), 100ms);
-    REQUIRE_FALSE(unwritable.locked());
-}
-
-TEST_CASE("InstanceLock retries a lock file it could not open once the cool-down passes", "[InstanceLock]")
-{
-    ScopedTemporaryDir dir;
-    const std::string  path = (dir.path() / "later" / "shared.lock").string();
-    ScopedStaticValue  cooldown(InstanceLock::cooldown, 300ms);
-
-    bool before_dir, during_cooldown, after_cooldown;
-    const auto started = std::chrono::steady_clock::now();
-    {
-        InstanceLock lock(path, 100ms);
-        before_dir = lock.locked();
-    }
-    boost::filesystem::create_directories(dir.path() / "later");
-    {
-        InstanceLock lock(path, 100ms);
-        during_cooldown = lock.locked();
-    }
-    const bool second_guard_inside_cooldown = std::chrono::steady_clock::now() - started < InstanceLock::cooldown;
-    std::this_thread::sleep_for(400ms);
-    {
-        InstanceLock lock(path, 100ms);
-        after_cooldown = lock.locked();
-    }
-
-    REQUIRE_FALSE(before_dir);
-    // A loaded runner may take longer than the cool-down to get here; then the
-    // second guard legitimately retried, so only assert when the timing held.
-    if (second_guard_inside_cooldown)
-        REQUIRE_FALSE(during_cooldown);
-    REQUIRE(after_cooldown);
-}
-
-TEST_CASE("InstanceLock reopens a lock file that was replaced on disk", "[InstanceLock]")
-{
-    ScopedTemporaryFile lock_file(".lock");
-    const std::string   path = lock_file.string();
-    {
-        InstanceLock lock(path);
-        REQUIRE(lock.locked());
-    }
-
-    boost::filesystem::remove(path);
-    InstanceLock lock(path);
-    REQUIRE(lock.locked());
-    // Each outermost guard opens the file afresh, so the deleted path is back.
-    REQUIRE(boost::filesystem::exists(path));
-}
-
-TEST_CASE("InstanceLock serialises the threads of one process", "[InstanceLock]")
-{
-    ScopedTemporaryFile lock_file(".lock");
-    const std::string   path = lock_file.string();
-
-    std::atomic<bool> holder_ready{false};
-    std::atomic<bool> holder_released{false};
-    std::thread holder([&] {
-        InstanceLock lock(path);
-        holder_ready = true;
-        std::this_thread::sleep_for(150ms);
-        holder_released = true;
-    });
-    while (! holder_ready)
-        std::this_thread::yield();
-
-    bool released_before_acquire = false;
-    {
-        InstanceLock lock(path);
-        released_before_acquire = holder_released;
-    }
-    holder.join();
-    REQUIRE(released_before_acquire);
-}
-
-// Holds the OS lock on a file through a handle of its own, as another instance would. The lock
-// belongs to the handle on Windows and to the open file description elsewhere, so the guard's
-// handle is refused while this one holds it.
-class OtherHolder
-{
-public:
-    explicit OtherHolder(const std::string &path)
-    {
-#ifdef _WIN32
-        boost::nowide::ofstream(path, std::ios::app).close();
-        m_lock = boost::interprocess::file_lock(boost::nowide::widen(path).c_str());
-        m_held = m_lock.try_lock();
-#else
-        m_fd   = ::open(path.c_str(), O_RDWR | O_CREAT, 0644);
-        m_held = m_fd >= 0 && ::flock(m_fd, LOCK_EX | LOCK_NB) == 0;
-#endif
-    }
-    ~OtherHolder() { release(); }
-    OtherHolder(const OtherHolder &) = delete;
-    OtherHolder &operator=(const OtherHolder &) = delete;
-
-    bool held() const { return m_held; }
-    void release()
-    {
-#ifdef _WIN32
-        if (m_held)
-            m_lock.unlock();
-        m_lock = boost::interprocess::file_lock();
-#else
-        if (m_fd >= 0)
-            ::close(m_fd);
-        m_fd = -1;
-#endif
-        m_held = false;
-    }
-
-private:
-#ifdef _WIN32
-    boost::interprocess::file_lock m_lock;
-#else
-    int m_fd{-1};
-#endif
-    bool m_held{false};
-};
-
-TEST_CASE("InstanceLock yields to a lock held through another handle and reports it", "[InstanceLock]")
-{
-    ScopedTemporaryFile lock_file(".lock");
-    const std::string   path = lock_file.string();
-    ScopedStaticValue   cooldown(InstanceLock::cooldown, 300ms);
-
-    OtherHolder other(path);
-    REQUIRE(other.held());
-
-    bool locked_while_other_holds;
-    {
-        InstanceLock lock(path, 100ms);
-        locked_while_other_holds = lock.locked();
-    }
-    // The timed-out wait starts a cool-down: the next guard does not touch the file.
-    const auto started = std::chrono::steady_clock::now();
-    bool       locked_during_cooldown;
-    {
-        InstanceLock lock(path, 5000ms);
-        locked_during_cooldown = lock.locked();
-    }
-    const auto cooldown_wait = std::chrono::steady_clock::now() - started;
-    other.release();
-
-    REQUIRE_FALSE(locked_while_other_holds);
-    REQUIRE_FALSE(locked_during_cooldown);
-    REQUIRE(cooldown_wait < 4000ms);
-    // Once the cool-down passes, the lock the other holder released is taken again.
-    std::this_thread::sleep_for(400ms);
-    InstanceLock lock(path);
-    REQUIRE(lock.locked());
-}

tests/libslic3r/test_kdtree.cpp

@@ -0,0 +1,67 @@
+#include <catch2/catch_all.hpp>
+
+#include <numeric>
+#include <random>
+#include <vector>
+
+#include "libslic3r/KDTreeIndirect.hpp"
+#include "libslic3r/Point.hpp"
+
+using namespace Slic3r;
+
+TEST_CASE("Visiting the nearby points gives what collecting them gives", "[KDTree]") {
+    std::mt19937                          rng(19937);
+    std::uniform_real_distribution<float> coord(-50.f, 50.f);
+    // Points in a box, so that a radius search returns anything from none of them to all of them.
+    std::vector<Vec3f> points(2000);
+    for (Vec3f &p : points)
+        p = Vec3f(coord(rng), coord(rng), coord(rng));
+
+    auto coordinate = [&points](size_t idx, size_t dimension) { return points[idx](int(dimension)); };
+    KDTreeIndirect<3, float, decltype(coordinate)> tree(coordinate);
+    std::vector<size_t> indices(points.size());
+    std::iota(indices.begin(), indices.end(), 0);
+    tree.build(indices);
+
+    const float radius = GENERATE(0.5f, 5.f, 25.f, 200.f);
+    for (int i = 0; i < 20; ++ i) {
+        const Vec3f center(coord(rng), coord(rng), coord(rng));
+
+        const std::vector<size_t> collected = find_nearby_points(tree, center, radius);
+        std::vector<size_t>       visited;
+        visit_nearby_points(tree, center, radius, [&visited](size_t idx) { visited.emplace_back(idx); });
+
+        // Same points, and in the same order: a caller that keeps the first of several equally good ones
+        // must get the same answer either way.
+        REQUIRE(visited == collected);
+    }
+}
+
+TEST_CASE("A radius search returns every point within the radius and no other", "[KDTree]") {
+    std::mt19937                          rng(2024);
+    std::uniform_real_distribution<float> coord(-20.f, 20.f);
+    std::vector<Vec3f> points(500);
+    for (Vec3f &p : points)
+        p = Vec3f(coord(rng), coord(rng), coord(rng));
+
+    auto coordinate = [&points](size_t idx, size_t dimension) { return points[idx](int(dimension)); };
+    KDTreeIndirect<3, float, decltype(coordinate)> tree(coordinate);
+    std::vector<size_t> indices(points.size());
+    std::iota(indices.begin(), indices.end(), 0);
+    tree.build(indices);
+
+    const Vec3f center(1.f, -2.f, 3.f);
+    const float radius = 7.f;
+
+    std::vector<size_t> expected;
+    for (size_t i = 0; i < points.size(); ++ i)
+        if ((points[i] - center).squaredNorm() < radius * radius)
+            expected.emplace_back(i);
+
+    std::vector<size_t> visited;
+    visit_nearby_points(tree, center, radius, [&visited](size_t idx) { visited.emplace_back(idx); });
+    std::sort(visited.begin(), visited.end());
+
+    REQUIRE(! expected.empty());
+    REQUIRE(visited == expected);
+}

tests/libslic3r/test_locales_utils.cpp

@@ -1,69 +0,0 @@
-#include <catch2/catch_all.hpp>
-
-#include <clocale>
-
-#include "libslic3r/LocalesUtils.hpp"
-
-using namespace Slic3r;
-
-namespace {
-
-// Switches this thread's numeric locale to one whose decimal separator is a comma,
-// when the system has one installed.
-struct CommaNumericLocale
-{
-#ifdef _WIN32
-    bool apply()
-    {
-        for (const char* name : { "de-DE", "German_Germany.1252" })
-            if (std::setlocale(LC_NUMERIC, name) != nullptr)
-                return true;
-        return false;
-    }
-#else
-    locale_t locale { (locale_t) 0 };
-    bool apply()
-    {
-        for (const char* name : { "de_DE.UTF-8", "de_DE.utf8", "de_DE" })
-            if ((locale = newlocale(LC_NUMERIC_MASK, name, (locale_t) 0)) != (locale_t) 0) {
-                uselocale(locale);
-                return true;
-            }
-        return false;
-    }
-    // Freed once the setters around apply() have put the thread's own locale back.
-    ~CommaNumericLocale()
-    {
-        if (locale != (locale_t) 0)
-            freelocale(locale);
-    }
-#endif
-};
-
-} // namespace
-
-TEST_CASE("a setter nested in another leaves the C locale in place for the outer one", "[LocalesUtils]")
-{
-    CNumericLocalesSetter outer;
-    {
-        CNumericLocalesSetter inner;
-        CHECK(is_decimal_separator_point());
-    }
-    CHECK(is_decimal_separator_point());
-}
-
-TEST_CASE("a setter nested in another sets C again when the locale changed between them", "[LocalesUtils]")
-{
-    CommaNumericLocale comma;
-    {
-        CNumericLocalesSetter outer;
-        if (! comma.apply())
-            SKIP("no locale with a comma decimal separator is installed");
-        REQUIRE_FALSE(is_decimal_separator_point());
-        {
-            CNumericLocalesSetter inner;
-            CHECK(is_decimal_separator_point());
-        }
-        CHECK_FALSE(is_decimal_separator_point());
-    }
-}

tests/libslic3r/test_parallel_resolve.cpp

@@ -1,122 +0,0 @@
-#include <catch2/catch_all.hpp>
-
-#include <numeric>
-#include <stdexcept>
-#include <thread>
-#include <vector>
-
-#include <tbb/blocked_range.h>
-#include <tbb/parallel_for.h>
-#include <tbb/task_group.h>
-
-#include "libslic3r/ParallelResolve.hpp"
-
-using namespace Slic3r;
-
-namespace {
-
-thread_local int t_live_setups = 0;
-
-// Counts how many are alive on the constructing thread.
-struct CountingSetup
-{
-    CountingSetup() { ++ t_live_setups; }
-    ~CountingSetup() { -- t_live_setups; }
-};
-
-std::vector<size_t> first_indices(size_t count)
-{
-    std::vector<size_t> indices(count);
-    std::iota(indices.begin(), indices.end(), size_t(0));
-    return indices;
-}
-
-} // namespace
-
-TEST_CASE("every item resolves once and commits in index order on the calling thread", "[ParallelResolve]")
-{
-    const size_t        count = 200;
-    std::vector<int>    resolves(count, 0);
-    std::vector<size_t> committed, values;
-    std::vector<bool>   on_caller;
-    const std::thread::id caller = std::this_thread::get_id();
-    resolve_then_commit(count,
-        [&](size_t i) { ++ resolves[i]; return i * 3; },
-        [&](size_t i, size_t resolved) {
-            committed.push_back(i);
-            values.push_back(resolved);
-            on_caller.push_back(std::this_thread::get_id() == caller);
-        });
-
-    CHECK(committed == first_indices(count));
-    for (size_t i = 0; i < count; ++ i) {
-        CHECK(resolves[i] == 1);
-        CHECK(values[i] == i * 3);
-        CHECK(on_caller[i]);
-    }
-}
-
-TEST_CASE("every item resolves inside one chunk setup", "[ParallelResolve]")
-{
-    const size_t     count = 200;
-    std::vector<int> live(count, 0);
-    resolve_then_commit<CountingSetup>(count,
-        [&](size_t i) { live[i] = t_live_setups; return 0; },
-        [](size_t, int) {});
-
-    for (size_t i = 0; i < count; ++ i)
-        CHECK(live[i] == 1);
-}
-
-TEST_CASE("an exception from resolve leaves the batches before it committed", "[ParallelResolve]")
-{
-    const size_t        count = 200, fails_at = 150;
-    REQUIRE(fails_at >= resolve_batch_size);
-    std::vector<size_t> committed;
-    CHECK_THROWS_AS(resolve_then_commit(count,
-                        [&](size_t i) {
-                            if (i == fails_at)
-                                throw std::runtime_error("resolve failed");
-                            return i;
-                        },
-                        [&](size_t i, size_t) { committed.push_back(i); }),
-                    std::runtime_error);
-
-    CHECK(committed == first_indices(fails_at / resolve_batch_size * resolve_batch_size));
-}
-
-TEST_CASE("an exception from commit stops at the item that threw", "[ParallelResolve]")
-{
-    const size_t        count = 200, fails_at = 90;
-    std::vector<size_t> committed;
-    CHECK_THROWS_AS(resolve_then_commit(count,
-                        [](size_t i) { return i; },
-                        [&](size_t i, size_t) {
-                            if (i == fails_at)
-                                throw std::runtime_error("commit failed");
-                            committed.push_back(i);
-                        }),
-                    std::runtime_error);
-
-    CHECK(committed == first_indices(fails_at));
-}
-
-TEST_CASE("a canceled task group stops before committing an item it did not resolve", "[ParallelResolve]")
-{
-    std::vector<size_t>     committed;
-    bool                    threw = false;
-    tbb::task_group_context context;
-    tbb::parallel_for(tbb::blocked_range<size_t>(0, 1), [&](const tbb::blocked_range<size_t>&) {
-        context.cancel_group_execution();
-        try {
-            resolve_then_commit(200,
-                [](size_t i) { return i + 1; },
-                [&](size_t, size_t resolved) { committed.push_back(resolved); });
-        } catch (const std::runtime_error&) {
-            threw = true;
-        }
-    }, context);
-
-    CHECK(threw);
-    CHECK(committed.empty());
-}

tests/libslic3r/test_preset_bundle_loading.cpp

@@ -5,7 +5,6 @@
 #include <fstream>
 
 #include "libslic3r/PresetBundle.hpp"
-#include "libslic3r/ParallelResolve.hpp"
 #include "libslic3r/AppConfig.hpp"
 #include "libslic3r/Model.hpp"
 #include "libslic3r/TriangleMesh.hpp"
@@ -18,10 +17,6 @@
 #include <iostream>
 #include <initializer_list>
 
-#ifndef _WIN32
-#include <unistd.h> // geteuid
-#endif
-
 using namespace Slic3r;
 
 namespace {
@@ -64,16 +59,6 @@ void write_preset_with_inherits(const DynamicPrintConfig &default_config, const
     config.save_to_json(file.string(), name, "User", "1.0.0");
 }
 
-// A user preset file stating nothing but the preset it inherits, so every value it
-// ends up with came from resolving that parent.
-void write_minimal_child(const fs::path &file, const std::string &name, const std::string &inherits)
-{
-    fs::create_directories(file.parent_path());
-    std::ofstream(file.string())
-        << R"({"type":"process","name":")" << name << R"(","from":"User","version":"1.0.0","inherits":")"
-        << inherits << R"("})";
-}
-
 // Add an in-memory preset (no file) with the given inherits value (empty => root preset).
 Preset &add_inmemory_preset(PresetCollection &coll, const std::string &name, const std::string &inherits = {})
 {
@@ -276,162 +261,6 @@ TEST_CASE("Selected printer uses its default or saved bed type", "[Preset][Bundl
     CHECK(app_config.get_printer_setting("Test Printer", "curr_bed_type") == std::to_string(static_cast<int>(expected_bed_type)));
 }
 
-TEST_CASE("A directory of user presets loads with each one resolved against its parent", "[Preset][Bundle]")
-{
-    ScopedTemporaryDir   temp_dir;
-    RenameTestCollection coll;
-
-    Preset &parent = add_inmemory_preset(coll, "Parent Process");
-    parent.config.option<ConfigOptionFloat>("layer_height", true)->value = 0.24;
-    parent.is_system = true;
-
-    constexpr int children = 400;
-    for (int i = 0; i < children; ++ i)
-        write_minimal_child(temp_dir.path() / PRESET_PRINT_NAME / ("Child " + std::to_string(i) + ".json"),
-                            "Child " + std::to_string(i), "Parent Process");
-
-    PresetsConfigSubstitutions substitutions;
-    coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                      ForwardCompatibilitySubstitutionRule::Disable);
-
-    CHECK(coll.size() == size_t(children) + 2); // the children, the default preset and the parent
-    CHECK(coll.error_count() == 0);
-    for (int i = 0; i < children; ++ i) {
-        const Preset *child = coll.find_preset("Child " + std::to_string(i));
-        REQUIRE(child != nullptr);
-        CHECK(child->inherits() == "Parent Process");
-        CHECK(child->alias == "Child " + std::to_string(i));
-        CHECK(child->loaded);
-        REQUIRE(child->config.option<ConfigOptionFloat>("layer_height") != nullptr);
-        CHECK_THAT(child->config.opt_float("layer_height"), Catch::Matchers::WithinAbs(0.24, 1e-9));
-    }
-}
-
-TEST_CASE("Repeated loads of a user preset directory produce the same presets", "[Preset][Bundle]")
-{
-    ScopedTemporaryDir temp_dir;
-
-    auto seed_directory = [&]() {
-        for (int i = 0; i < 200; ++ i)
-            write_minimal_child(temp_dir.path() / PRESET_PRINT_NAME / ("Child " + std::to_string(i) + ".json"),
-                                "Child " + std::to_string(i), "Parent Process");
-    };
-
-    std::vector<std::vector<std::string>> names_per_run;
-    for (int run = 0; run < 3; ++ run) {
-        RenameTestCollection coll;
-        Preset &parent = add_inmemory_preset(coll, "Parent Process");
-        parent.is_system = true;
-        if (run == 0)
-            seed_directory();
-
-        PresetsConfigSubstitutions substitutions;
-        coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                          ForwardCompatibilitySubstitutionRule::Disable);
-
-        std::vector<std::string> names;
-        for (auto it = coll.begin(); it != coll.end(); ++ it)
-            names.push_back(it->name + "|" + it->alias + "|" + it->inherits());
-        names_per_run.push_back(std::move(names));
-    }
-
-    REQUIRE(names_per_run[0].size() > 200);
-    CHECK(names_per_run[1] == names_per_run[0]);
-    CHECK(names_per_run[2] == names_per_run[0]);
-}
-
-TEST_CASE("An unreadable user preset is counted and removed while the rest still load", "[Preset][Bundle]")
-{
-    ScopedTemporaryDir   temp_dir;
-    RenameTestCollection coll;
-    const fs::path       dir = temp_dir.path() / PRESET_PRINT_NAME;
-
-    for (int i = 0; i < 20; ++ i)
-        write_preset_with_inherits(coll.default_preset().config, dir / ("Good " + std::to_string(i) + ".json"),
-                                   "Good " + std::to_string(i), std::string());
-    fs::create_directories(dir);
-    std::ofstream((dir / "Broken.json").string()) << "{not-json";
-
-    PresetsConfigSubstitutions substitutions;
-    coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                      ForwardCompatibilitySubstitutionRule::EnableSilent);
-
-    CHECK(coll.error_count() == 1);
-    CHECK(coll.find_preset("Broken") == nullptr);
-    CHECK_FALSE(fs::exists(dir / "Broken.json"));
-    for (int i = 0; i < 20; ++ i)
-        CHECK(coll.find_preset("Good " + std::to_string(i)) != nullptr);
-}
-
-TEST_CASE("A user filament naming no compatible printer gets the one after its @, in memory and on disk", "[Preset][Bundle]")
-{
-    ScopedTemporaryDir temp_dir;
-    PresetBundle       bundle;
-    const fs::path     file = temp_dir.path() / PRESET_FILAMENT_NAME / "My PLA @Test Printer.json";
-    REQUIRE(bundle.filaments.default_preset().config.option<ConfigOptionStrings>("compatible_printers")->values.empty());
-    write_preset_with_inherits(bundle.filaments.default_preset().config, file, "My PLA @Test Printer", std::string());
-
-    PresetsConfigSubstitutions substitutions;
-    bundle.filaments.load_presets(temp_dir.path().string(), PRESET_FILAMENT_NAME, substitutions,
-                                  ForwardCompatibilitySubstitutionRule::EnableSilent);
-
-    const std::vector<std::string> expected { "Test Printer" };
-    const Preset *preset = bundle.filaments.find_preset("My PLA @Test Printer");
-    REQUIRE(preset != nullptr);
-    CHECK(preset->config.option<ConfigOptionStrings>("compatible_printers")->values == expected);
-
-    DynamicPrintConfig                 saved;
-    std::map<std::string, std::string> key_values;
-    std::string                        reason;
-    saved.load_from_json(file.string(), ForwardCompatibilitySubstitutionRule::EnableSilent, key_values, reason);
-    REQUIRE(reason.empty());
-    REQUIRE(saved.option<ConfigOptionStrings>("compatible_printers") != nullptr);
-    CHECK(saved.option<ConfigOptionStrings>("compatible_printers")->values == expected);
-}
-
-TEST_CASE("A user preset's setting id equal to its base id is dropped in memory, not in the .info written back", "[Preset][Bundle]")
-{
-    ScopedTemporaryDir temp_dir;
-    PresetBundle       bundle;
-    const fs::path     file = temp_dir.path() / PRESET_FILAMENT_NAME / "My PLA @Test Printer.json";
-    write_preset_with_inherits(bundle.filaments.default_preset().config, file, "My PLA @Test Printer", std::string());
-    fs::path info = file;
-    info.replace_extension(".info");
-    std::ofstream(info.string()) << "sync_info = \nuser_id = \nsetting_id = PFUS1\nbase_id = PFUS1\nupdated_time = 0\n";
-
-    PresetsConfigSubstitutions substitutions;
-    bundle.filaments.load_presets(temp_dir.path().string(), PRESET_FILAMENT_NAME, substitutions,
-                                  ForwardCompatibilitySubstitutionRule::EnableSilent);
-
-    const Preset *preset = bundle.filaments.find_preset("My PLA @Test Printer");
-    REQUIRE(preset != nullptr);
-    CHECK(preset->setting_id.empty());
-    CHECK(preset->base_id == "PFUS1");
-    Preset reloaded(Preset::TYPE_FILAMENT, "My PLA @Test Printer");
-    reloaded.load_info(info.string());
-    CHECK(reloaded.setting_id == "PFUS1");
-}
-
-TEST_CASE("A user preset that is not loaded still reports its substituted values", "[Preset][Bundle]")
-{
-    ScopedTemporaryDir   temp_dir;
-    RenameTestCollection coll;
-    const fs::path       dir = temp_dir.path() / PRESET_PRINT_NAME;
-    fs::create_directories(dir);
-    std::ofstream((dir / "Orphan.json").string())
-        << R"({"type":"process","name":"Orphan","from":"User","version":"1.0.0","inherits":"No Such Parent",)"
-        << R"("wall_generator":"no_such_generator"})";
-
-    PresetsConfigSubstitutions substitutions;
-    coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                      ForwardCompatibilitySubstitutionRule::Enable);
-
-    CHECK(coll.find_preset("Orphan") == nullptr);
-    CHECK(coll.error_count() == 1);
-    REQUIRE(substitutions.size() == 1);
-    CHECK(substitutions.front().preset_name == "Orphan");
-}
-
 TEST_CASE("find_preset resolves a system preset's renamed_from", "[Preset][Rename]")
 {
     RenameTestCollection coll;
@@ -5653,214 +5482,3 @@ TEST_CASE("Config import confines zip entries, preset names and bundle ids to th
         CHECK_FALSE(any_filename_contains(temp_dir.path(), "bundle-escape"));
     }
 }
-
-TEST_CASE("A user preset saved over by another instance while its directory loads is read again under the lock", "[Preset][Bundle][InstanceLock]")
-{
-    ScopedTemporaryDir   temp_dir;
-    ScopedDataDir        data_dir_scope(temp_dir.path());
-    RenameTestCollection coll;
-
-    Preset &parent = add_inmemory_preset(coll, "Parent Process");
-    parent.config.option<ConfigOptionFloat>("layer_height", true)->value = 0.24;
-    parent.is_system = true;
-
-    // Fewer than one batch, so every file is read before the first one is committed.
-    constexpr int  children = 8;
-    static_assert(children <= int(resolve_batch_size));
-    const fs::path dir      = temp_dir.path() / PRESET_PRINT_NAME;
-    for (int i = 0; i < children; ++ i)
-        write_minimal_child(dir / ("Child " + std::to_string(i) + ".json"), "Child " + std::to_string(i), "Parent Process");
-
-    // The first commit stands in for another instance saving every other preset after
-    // they were read and before they are committed.
-    std::string first;
-    auto save_the_others = [&](Preset &preset) {
-        if (! first.empty())
-            return;
-        first = preset.name;
-        for (int i = 0; i < children; ++ i) {
-            const std::string name = "Child " + std::to_string(i);
-            if (name != first)
-                std::ofstream((dir / (name + ".json")).string())
-                    << R"({"type":"process","name":")" << name
-                    << R"(","from":"User","version":"1.0.0","inherits":"Parent Process","layer_height":"0.3"})";
-        }
-    };
-    PresetsConfigSubstitutions substitutions;
-    coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                      ForwardCompatibilitySubstitutionRule::Disable, save_the_others);
-
-    REQUIRE_FALSE(first.empty());
-    CHECK(coll.error_count() == 0);
-    for (int i = 0; i < children; ++ i) {
-        const std::string name  = "Child " + std::to_string(i);
-        const Preset     *child = coll.find_preset(name);
-        REQUIRE(child != nullptr);
-        CHECK_THAT(child->config.opt_float("layer_height"), Catch::Matchers::WithinAbs(name == first ? 0.24 : 0.3, 1e-9));
-    }
-}
-
-TEST_CASE("A user preset removed by another instance while its directory loads is not installed", "[Preset][Bundle][InstanceLock]")
-{
-    ScopedTemporaryDir   temp_dir;
-    ScopedDataDir        data_dir_scope(temp_dir.path());
-    RenameTestCollection coll;
-
-    Preset &parent = add_inmemory_preset(coll, "Parent Process");
-    parent.is_system = true;
-
-    // Fewer than one batch, so every file is read before the first one is committed.
-    constexpr int  children = 8;
-    static_assert(children <= int(resolve_batch_size));
-    const fs::path dir      = temp_dir.path() / PRESET_PRINT_NAME;
-    for (int i = 0; i < children; ++ i)
-        write_minimal_child(dir / ("Child " + std::to_string(i) + ".json"), "Child " + std::to_string(i), "Parent Process");
-
-    std::string first;
-    auto remove_the_others = [&](Preset &preset) {
-        if (! first.empty())
-            return;
-        first = preset.name;
-        for (int i = 0; i < children; ++ i)
-            if (const std::string name = "Child " + std::to_string(i); name != first)
-                fs::remove(dir / (name + ".json"));
-    };
-    PresetsConfigSubstitutions substitutions;
-    coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                      ForwardCompatibilitySubstitutionRule::Disable, remove_the_others);
-
-    REQUIRE_FALSE(first.empty());
-    CHECK(coll.error_count() == 0);
-    CHECK(coll.size() == 3); // the default preset, the parent and the first child
-    CHECK(coll.find_preset(first) != nullptr);
-}
-
-TEST_CASE("Without the instance lock a user preset loads but its file is not written back", "[Preset][Bundle][InstanceLock]")
-{
-    ScopedTemporaryDir temp_dir;
-    ScopedDataDir      data_dir_scope(temp_dir.path());
-    // A directory where the lock file belongs, so the lock cannot be taken.
-    fs::create_directories(fs::path(user_presets_lock_path()));
-    PresetBundle       bundle;
-    const fs::path     file = temp_dir.path() / PRESET_FILAMENT_NAME / "My PLA @Test Printer.json";
-    write_preset_with_inherits(bundle.filaments.default_preset().config, file, "My PLA @Test Printer", std::string());
-    const std::string before = read_file(file);
-
-    PresetsConfigSubstitutions substitutions;
-    bundle.filaments.load_presets(temp_dir.path().string(), PRESET_FILAMENT_NAME, substitutions,
-                                  ForwardCompatibilitySubstitutionRule::EnableSilent);
-
-    const Preset *preset = bundle.filaments.find_preset("My PLA @Test Printer");
-    REQUIRE(preset != nullptr);
-    CHECK(preset->config.option<ConfigOptionStrings>("compatible_printers")->values == std::vector<std::string>{ "Test Printer" });
-    CHECK(read_file(file) == before);
-}
-
-#ifndef _WIN32
-// File permissions stop reading only on POSIX.
-TEST_CASE("A user preset that cannot be read under the instance lock is counted and removed", "[Preset][Bundle][InstanceLock]")
-{
-    if (::geteuid() == 0)
-        SKIP("file permissions do not stop root");
-    ScopedTemporaryDir   temp_dir;
-    ScopedDataDir        data_dir_scope(temp_dir.path());
-    RenameTestCollection coll;
-
-    Preset &parent = add_inmemory_preset(coll, "Parent Process");
-    parent.is_system = true;
-    const fs::path file = temp_dir.path() / PRESET_PRINT_NAME / "Unreadable.json";
-    write_minimal_child(file, "Unreadable", "Parent Process");
-    fs::permissions(file, fs::no_perms);
-
-    PresetsConfigSubstitutions substitutions;
-    coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                      ForwardCompatibilitySubstitutionRule::Disable);
-
-    CHECK(coll.error_count() == 1);
-    CHECK(coll.find_preset("Unreadable") == nullptr);
-    CHECK_FALSE(fs::exists(file));
-}
-#endif
-
-#ifndef _WIN32
-// Creating a symlink needs no privilege only on POSIX.
-TEST_CASE("A user preset that is a symlink to itself is counted and removed while the rest still load", "[Preset][Bundle][InstanceLock]")
-{
-    ScopedTemporaryDir   temp_dir;
-    ScopedDataDir        data_dir_scope(temp_dir.path());
-    RenameTestCollection coll;
-
-    Preset &parent = add_inmemory_preset(coll, "Parent Process");
-    parent.is_system = true;
-    const fs::path dir = temp_dir.path() / PRESET_PRINT_NAME;
-    write_minimal_child(dir / "Good A.json", "Good A", "Parent Process");
-    write_minimal_child(dir / "Good B.json", "Good B", "Parent Process");
-    const fs::path loop = dir / "Loop.json";
-    fs::create_symlink(loop.filename(), loop);
-
-    PresetsConfigSubstitutions substitutions;
-    REQUIRE_NOTHROW(coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                                      ForwardCompatibilitySubstitutionRule::Disable));
-
-    CHECK(coll.error_count() == 1);
-    CHECK(coll.find_preset("Good A") != nullptr);
-    CHECK(coll.find_preset("Good B") != nullptr);
-    CHECK(coll.find_preset("Loop") == nullptr);
-    boost::system::error_code ec;
-    CHECK(fs::symlink_status(loop, ec).type() == fs::file_not_found);
-}
-#endif
-
-#ifndef _WIN32
-// Creating a symlink needs no privilege only on POSIX.
-TEST_CASE("A user preset symlinked to a missing target is counted but the link is kept", "[Preset][Bundle][InstanceLock]")
-{
-    ScopedTemporaryDir   temp_dir;
-    ScopedDataDir        data_dir_scope(temp_dir.path());
-    RenameTestCollection coll;
-
-    const fs::path dir  = temp_dir.path() / PRESET_PRINT_NAME;
-    const fs::path link = dir / "Linked.json";
-    fs::create_directories(dir);
-    fs::create_symlink(temp_dir.path() / "unmounted" / "Linked.json", link);
-
-    PresetsConfigSubstitutions substitutions;
-    coll.load_presets(temp_dir.path().string(), PRESET_PRINT_NAME, substitutions,
-                      ForwardCompatibilitySubstitutionRule::Disable);
-
-    CHECK(coll.error_count() == 1);
-    CHECK(coll.find_preset("Linked") == nullptr);
-    boost::system::error_code ec;
-    CHECK(fs::symlink_status(link, ec).type() == fs::symlink_file);
-}
-#endif
-
-#ifndef _WIN32
-// The read-only bit on a directory stops file creation only on POSIX.
-TEST_CASE("A user filament whose derived compatible printer cannot be written back still loads with the failure counted", "[Preset][Bundle]")
-{
-    if (::geteuid() == 0)
-        SKIP("a read-only directory does not stop root");
-    ScopedTemporaryDir temp_dir;
-    PresetBundle       bundle;
-    const fs::path     dir  = temp_dir.path() / PRESET_FILAMENT_NAME;
-    const fs::path     file = dir / "My PLA @Test Printer.json";
-    write_preset_with_inherits(bundle.filaments.default_preset().config, file, "My PLA @Test Printer", std::string());
-    const std::string before = read_file(file);
-
-    fs::permissions(file, fs::owner_read);
-    fs::permissions(dir, fs::owner_read | fs::owner_exe);
-    PresetsConfigSubstitutions substitutions;
-    bundle.filaments.load_presets(temp_dir.path().string(), PRESET_FILAMENT_NAME, substitutions,
-                                  ForwardCompatibilitySubstitutionRule::EnableSilent);
-    // Restored before any assertion, so a failure never leaves an unremovable directory behind.
-    fs::permissions(dir, fs::owner_all);
-    fs::permissions(file, fs::owner_read | fs::owner_write);
-
-    const Preset *preset = bundle.filaments.find_preset("My PLA @Test Printer");
-    REQUIRE(preset != nullptr);
-    CHECK(preset->config.option<ConfigOptionStrings>("compatible_printers")->values == std::vector<std::string>{ "Test Printer" });
-    CHECK(bundle.filaments.error_count() == 1);
-    CHECK(read_file(file) == before);
-}
-#endif

tests/libslic3r/test_utils.cpp

@@ -10,8 +10,6 @@
 #include <cctype>
 #include <fstream>
 #include <string>
-#include <thread>
-#include <system_error>
 
 #ifndef _WIN32
 #include <unistd.h>     // getuid
@@ -64,113 +62,6 @@ TEST_CASE("per-user temp root is unchanged on Windows, isolated elsewhere", "[ut
 #endif
 }
 
-TEST_CASE("write_file_atomically replaces the target and leaves no temporary file", "[utils]") {
-    ScopedTemporaryDir dir;
-    const boost::filesystem::path target = dir.path() / "preset.json";
-
-    REQUIRE_FALSE(write_file_atomically(target.string(), "first"));
-    REQUIRE_FALSE(write_file_atomically(target.string(), "second"));
-
-    std::string content;
-    load_string_file(target, content);
-    REQUIRE(content == "second");
-    size_t entries = 0;
-    for (auto &entry : boost::filesystem::directory_iterator(dir.path())) {
-        (void) entry;
-        ++entries;
-    }
-    REQUIRE(entries == 1);
-}
-
-TEST_CASE("write_file_atomically reports a missing directory and writes nothing", "[utils]") {
-    ScopedTemporaryDir dir;
-    const boost::filesystem::path target = dir.path() / "missing" / "preset.json";
-
-    const std::error_code ec = write_file_atomically(target.string(), "x");
-    REQUIRE(ec == std::errc::no_such_file_or_directory);
-    REQUIRE_FALSE(boost::filesystem::exists(target));
-}
-
-#ifndef _WIN32
-// The read-only bit on a directory stops file creation only on POSIX.
-TEST_CASE("write_file_atomically writes in place when no temporary can be created beside an existing target", "[utils]") {
-    if (::geteuid() == 0)
-        SKIP("a read-only directory does not stop root");
-    ScopedTemporaryDir dir;
-    const boost::filesystem::path target = dir.path() / "preset.json";
-    REQUIRE_FALSE(write_file_atomically(target.string(), "first"));
-    boost::filesystem::permissions(dir.path(), boost::filesystem::owner_read | boost::filesystem::owner_exe);
-
-    const std::error_code replaced = write_file_atomically(target.string(), "second");
-    const std::error_code created  = write_file_atomically((dir.path() / "new.json").string(), "x");
-    // Restored before any assertion, so a failure never leaves an unremovable directory behind.
-    boost::filesystem::permissions(dir.path(), boost::filesystem::owner_all);
-
-    REQUIRE_FALSE(replaced);
-    REQUIRE(created == std::errc::permission_denied);
-    std::string content;
-    load_string_file(target, content);
-    REQUIRE(content == "second");
-}
-#endif
-
-TEST_CASE("write_file_atomically keeps bytes intact in binary mode", "[utils]") {
-    ScopedTemporaryDir dir;
-    const boost::filesystem::path target = dir.path() / "blob.bin";
-    const std::string bytes("a\r\nb\0c", 6);
-
-    REQUIRE_FALSE(write_file_atomically(target.string(), bytes, /*binary=*/true));
-    REQUIRE(boost::filesystem::file_size(target) == bytes.size());
-}
-
-#ifndef _WIN32
-TEST_CASE("write_file_atomically writes through a symlink and keeps the target's permissions", "[utils]") {
-    ScopedTemporaryDir dir;
-    const boost::filesystem::path real = dir.path() / "real.json";
-    const boost::filesystem::path link = dir.path() / "link.json";
-    REQUIRE_FALSE(write_file_atomically(real.string(), "first"));
-    boost::filesystem::permissions(real, boost::filesystem::owner_read | boost::filesystem::owner_write);
-    boost::filesystem::create_symlink(real, link);
-
-    REQUIRE_FALSE(write_file_atomically(link.string(), "second"));
-
-    REQUIRE(boost::filesystem::is_symlink(boost::filesystem::symlink_status(link)));
-    std::string content;
-    load_string_file(real, content);
-    REQUIRE(content == "second");
-
-    REQUIRE_FALSE(write_file_atomically(real.string(), "third"));
-    const auto perms = boost::filesystem::status(real).permissions() & boost::filesystem::all_all;
-    REQUIRE(perms == (boost::filesystem::owner_read | boost::filesystem::owner_write));
-}
-#endif
-
-TEST_CASE("write_file_atomically survives two threads writing one target", "[utils]") {
-    ScopedTemporaryDir dir;
-    const boost::filesystem::path target = dir.path() / "shared.json";
-    const std::string a(20000, 'a'), b(20000, 'b');
-
-    std::thread other([&] {
-        for (int i = 0; i < 50; ++i)
-            write_file_atomically(target.string(), a);
-    });
-    for (int i = 0; i < 50; ++i)
-        write_file_atomically(target.string(), b);
-    other.join();
-
-    std::string content;
-    load_string_file(target, content);
-    const bool whole = content == a || content == b;
-    REQUIRE(whole);
-    // No temporary may be left; a scanner on Windows may briefly hold the old
-    // file under another name, so only the temporaries are counted.
-    size_t temporaries = 0;
-    for (auto &entry : boost::filesystem::directory_iterator(dir.path()))
-        if (entry.path().extension() == ".tmp")
-            ++temporaries;
-    REQUIRE(temporaries == 0);
-}
-
 TEST_CASE("copy_file reports the OS error when the destination cannot be written", "[utils]") {
     ScopedTemporaryFile source(".txt");
     {

tests/libslic3r/test_vendor_cache.cpp

@@ -3,21 +3,12 @@
 #include <boost/filesystem.hpp>
 #include <boost/crc.hpp>
 #include <cereal/archives/binary.hpp>
-#include <algorithm>
-#include <atomic>
 #include <cstring>
 #include <fstream>
 #include <functional>
-#include <memory>
-#include <numeric>
-#include <random>
 #include <set>
 #include <sstream>
 
-#include <tbb/blocked_range.h>
-#include <tbb/parallel_for.h>
-#include <tbb/task_group.h>
-
 #include "libslic3r/PresetBundle.hpp"
 #include "libslic3r/PresetCacheFormat.hpp"
 #include "libslic3r/Preset.hpp"
@@ -61,27 +52,6 @@ void write_vendor_tree(const fs::path& dir, const std::string& vendor, const std
         << R"(","from":"system","instantiation":"true","layer_height":"0.2"})";
 }
 
-// A vendor whose process list is `processes`, each a preset name and the text of
-// its sub-file, listed in that order.
-void write_process_vendor(const fs::path& dir, const std::string& vendor,
-                          const std::vector<std::pair<std::string, std::string>>& processes)
-{
-    fs::create_directories(dir / vendor / "process");
-    std::ofstream index((dir / (vendor + ".json")).string());
-    index << R"({"version":"1.0.0","name":")" << vendor << R"(","process_list":[)";
-    for (size_t i = 0; i < processes.size(); ++ i) {
-        const std::string sub_path = "process/p" + std::to_string(i) + ".json";
-        index << (i ? "," : "") << R"({"name":")" << processes[i].first << R"(","sub_path":")" << sub_path << R"("})";
-        std::ofstream((dir / vendor / sub_path).string()) << processes[i].second;
-    }
-    index << "]}";
-}
-
-std::string process_json(const std::string& name, const std::string& extra = std::string())
-{
-    return R"({"type":"process","name":")" + name + R"(","from":"system",)" + extra + R"("layer_height":"0.2"})";
-}
-
 // A small but complete vendor: one machine model, one process, a non-instantiated
 // base filament with an instantiated child that inherits it and includes a
 // dual-extruder template, a second standalone filament carrying explicit
@@ -158,80 +128,6 @@ void write_lib_tree(const fs::path& dir, const std::string& version, const std::
         << R"("filament_id":"GFL99","filament_cost":")" << cost << R"("})";
 }
 
-struct FixtureEntry {
-    std::string         name, sub_path;
-    std::vector<size_t> deps;   // indices of the entries this one inherits or includes
-};
-
-// Filaments with two levels of inheritance, a template to include, and `leaves`
-// presets that inherit either level, some including the template. Only the
-// subfiles are written; write_filament_list lists them.
-std::vector<FixtureEntry> write_layered_filaments(const fs::path& dir, const std::string& vendor, int leaves)
-{
-    fs::create_directories(dir / vendor / "filament");
-    std::vector<FixtureEntry> entries {
-        { vendor + " Base PLA", "filament/base.json", {} },
-        { vendor + " Mid PLA", "filament/mid.json", {0} },
-        { vendor + " dual template", "filament/template.json", {} },
-    };
-    std::ofstream((dir / vendor / "filament" / "base.json").string())
-        << R"({"type":"filament","name":")" << entries[0].name << R"(","from":"system","instantiation":"false",)"
-        << R"("filament_id":"GFA_base","filament_cost":"42","filament_max_volumetric_speed":["12"]})";
-    std::ofstream((dir / vendor / "filament" / "mid.json").string())
-        << R"({"type":"filament","name":")" << entries[1].name << R"(","from":"system","instantiation":"false",)"
-        << R"("inherits":")" << entries[0].name << R"(","filament_flow_ratio":"0.95"})";
-    std::ofstream((dir / vendor / "filament" / "template.json").string())
-        << R"({"type":"filament","name":")" << entries[2].name << R"(","from":"system","instantiation":"false",)"
-        << R"("filament_extruder_variant":["Direct Drive Standard","Direct Drive High Flow"],)"
-        << R"("filament_max_volumetric_speed":["20","22"]})";
-    for (int i = 0; i < leaves; ++ i) {
-        const size_t parent  = i % 2;
-        const bool   include = i % 3 == 0;
-        entries.push_back({ vendor + " PLA " + std::to_string(i) + " @0.4", "filament/leaf" + std::to_string(i) + ".json",
-                            include ? std::vector<size_t>{parent, 2} : std::vector<size_t>{parent} });
-        std::ofstream((dir / vendor / entries.back().sub_path).string())
-            << R"({"type":"filament","name":")" << entries.back().name << R"(","from":"system","instantiation":"true",)"
-            << R"("inherits":")" << entries[parent].name << R"(",)"
-            << (include ? R"("include":[")" + entries[2].name + R"("],)" : std::string())
-            << R"("nozzle_temperature":[")" << (200 + i % 40) << R"("]})";
-    }
-    return entries;
-}
-
-// The vendor profile for write_layered_filaments, listing its entries in `order`,
-// or as they were written when `order` is empty.
-void write_filament_list(const fs::path& dir, const std::string& vendor, const std::vector<FixtureEntry>& entries,
-                         std::vector<size_t> order = {})
-{
-    if (order.empty()) {
-        order.resize(entries.size());
-        std::iota(order.begin(), order.end(), 0);
-    }
-    std::ofstream f((dir / (vendor + ".json")).string());
-    f << R"({"version":"1.0.0","name":")" << vendor << R"(","filament_list":[)";
-    for (size_t k = 0; k < order.size(); ++ k)
-        f << (k ? "," : "") << R"({"name":")" << entries[order[k]].name << R"(","sub_path":")"
-          << entries[order[k]].sub_path << R"("})";
-    f << "]}";
-}
-
-// A random order of `entries` that lists each one after everything it depends on.
-std::vector<size_t> shuffled_after_dependencies(const std::vector<FixtureEntry>& entries, std::mt19937& rng)
-{
-    std::vector<size_t> order;
-    std::vector<bool>   listed(entries.size(), false);
-    while (order.size() < entries.size()) {
-        std::vector<size_t> ready;
-        for (size_t i = 0; i < entries.size(); ++ i)
-            if (! listed[i] && std::all_of(entries[i].deps.begin(), entries[i].deps.end(), [&](size_t d) { return listed[d]; }))
-                ready.push_back(i);
-        const size_t next = ready[std::uniform_int_distribution<size_t>(0, ready.size() - 1)(rng)];
-        listed[next] = true;
-        order.push_back(next);
-    }
-    return order;
-}
-
 // A vendor whose one filament inherits the library's base and states nothing of
 // its own — everything it shows comes from the library it is resolved against.
 void write_vendor_with_lib_filament(const fs::path& dir, const std::string& vendor, const std::string& version)
@@ -728,299 +624,6 @@ TEST_CASE("a cache-loaded vendor is indistinguishable from a JSON-loaded one", "
     CHECK(pr->config.opt_string("machine_start_gcode") == "G28 ; template");   // through the include
 }
 
-TEST_CASE("a wide vendor loads from its cache exactly as it loads from JSON", "[VendorCache]")
-{
-    InstallDirs dirs;
-    constexpr int leaves = 400;
-    write_filament_list(dirs.system, "Acme", write_layered_filaments(dirs.system, "Acme", leaves));
-
-    PresetBundle from_json;
-    from_json.set_generate_vendor_caches(true);
-    from_json.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                            ForwardCompatibilitySubstitutionRule::EnableSilent);
-    REQUIRE(fs::exists(dirs.system / "Acme.opc"));
-
-    fs::remove_all(dirs.system / "Acme");
-    PresetBundle from_cache;
-    from_cache.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                             ForwardCompatibilitySubstitutionRule::EnableSilent);
-
-    auto a = presets_for(from_json.filaments, "Acme");
-    auto b = presets_for(from_cache.filaments, "Acme");
-    REQUIRE(a.size() == size_t(leaves));
-    REQUIRE(b.size() == a.size());
-    for (size_t i = 0; i < a.size(); ++ i) {
-        CHECK(a[i]->name == b[i]->name);
-        CHECK(preset_deep_equal(*a[i], *b[i]));
-    }
-    CHECK(from_cache.error_count() == from_json.error_count());
-    // The two-level chain resolved, so the leaf has the middle profile's flow ratio
-    // and the base profile's filament id, neither of which it states.
-    const Preset* leaf = from_cache.filaments.find_preset("Acme PLA 7 @0.4", false);
-    REQUIRE(leaf != nullptr);
-    CHECK(leaf->filament_id == "GFA_base");
-    const auto* flow = leaf->config.option<ConfigOptionFloats>("filament_flow_ratio");
-    REQUIRE(flow != nullptr);
-    CHECK_THAT(flow->values.front(), WithinAbs(0.95, 1e-9));
-}
-
-TEST_CASE("presets install the same in any order that lists each after what it depends on", "[VendorCache]")
-{
-    InstallDirs dirs;
-    const std::vector<FixtureEntry> entries = write_layered_filaments(dirs.system, "Acme", 150);
-    auto load = [&](const std::vector<size_t>& order) {
-        write_filament_list(dirs.system, "Acme", entries, order);
-        auto bundle = std::make_unique<PresetBundle>();
-        bundle->load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                              ForwardCompatibilitySubstitutionRule::EnableSilent);
-        return bundle;
-    };
-    const auto reference = load({});
-    CHECK(reference->error_count() == 0);
-    const auto expected = presets_for(reference->filaments, "Acme");
-    REQUIRE(expected.size() == 150);
-
-    // Every seed checks against one reference load, which GENERATE would repeat per seed.
-    for (unsigned seed = 0; seed < 8; ++ seed) {
-        CAPTURE(seed);
-        std::mt19937 rng(seed);
-        const auto shuffled = load(shuffled_after_dependencies(entries, rng));
-        CHECK(shuffled->error_count() == 0);
-        const auto actual = presets_for(shuffled->filaments, "Acme");
-        REQUIRE(actual.size() == expected.size());
-        for (size_t i = 0; i < actual.size(); ++ i)
-            CHECK(preset_deep_equal(*actual[i], *expected[i]));
-    }
-}
-
-TEST_CASE("a key misplaced into a vendor preset is reported and removed", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_process_vendor(dirs.system, "Acme", {
-        { "Acme template", R"({"type":"process","name":"Acme template","from":"system","instantiation":"false","wall_loops":"5","filament_density":"1.2"})" },
-        { "Acme base", R"({"type":"process","name":"Acme base","from":"system","instantiation":"false","filament_cost":"5"})" },
-        { "0.20mm Standard @Acme", process_json("0.20mm Standard @Acme",
-            R"("instantiation":"true","inherits":"Acme base","include":["Acme template"],"nozzle_temperature":["210"],)") } });
-    PresetBundle bundle;
-    bundle.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                         ForwardCompatibilitySubstitutionRule::EnableSilent);
-
-    CHECK(bundle.error_count() == 3);
-    const Preset* preset = bundle.prints.find_preset("0.20mm Standard @Acme", false);
-    REQUIRE(preset != nullptr);
-    CHECK_FALSE(preset->config.has("filament_cost"));
-    CHECK_FALSE(preset->config.has("filament_density"));
-    CHECK_FALSE(preset->config.has("nozzle_temperature"));
-    CHECK(preset->config.opt_int("wall_loops") == 5);
-}
-
-TEST_CASE("each vendor loads from the directory it is listed with", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_vendor_tree(dirs.system, "Acme", "1.0.0");
-    write_vendor_tree(dirs.profiles, "Zeta", "2.0.0");
-    PresetBundle bundle;
-    bundle.load_vendors({ { "Acme", dirs.system }, { "Zeta", dirs.profiles } },
-                        ForwardCompatibilitySubstitutionRule::EnableSilent, /*allow_cache=*/false);
-
-    CHECK(bundle.vendors.count("Acme") == 1);
-    CHECK(bundle.vendors.count("Zeta") == 1);
-    CHECK(bundle.prints.find_preset("0.20mm Standard @Acme", false) != nullptr);
-    CHECK(bundle.prints.find_preset("0.20mm Standard @Zeta", false) != nullptr);
-}
-
-TEST_CASE("a vendor that fails to load is left out, reported, and the others still load", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_vendor_tree(dirs.system, "Acme", "1.0.0");
-    write_process_vendor(dirs.system, "Broken", { { "Broken A", "{not-json" } });
-    PresetBundle             bundle;
-    std::vector<std::string> failed;
-    const std::string errors = bundle.load_vendors({ { "Acme", dirs.system }, { "Broken", dirs.system } },
-                                                   ForwardCompatibilitySubstitutionRule::EnableSilent,
-                                                   /*allow_cache=*/false, nullptr, &failed).second;
-
-    CHECK(bundle.vendors.count("Acme") == 1);
-    CHECK(bundle.vendors.count("Broken") == 0);
-    CHECK(bundle.prints.find_preset("0.20mm Standard @Acme", false) != nullptr);
-    CHECK(errors.find("Broken") != std::string::npos);
-    CHECK(failed == std::vector<std::string>{ "Broken" });
-}
-
-TEST_CASE("a filament library that fails partway is reported, and vendors inheriting from it are left out", "[VendorCache]")
-{
-    InstallDirs dirs;
-    const std::string lib(PresetBundle::ORCA_FILAMENT_LIBRARY);
-    write_lib_tree(dirs.system, "1.0.0", "20");
-    std::ofstream((dirs.system / (lib + ".json")).string())
-        << R"({"version":"1.0.0","name":")" << lib << R"(","filament_list":[)"
-        << R"({"name":"Generic PLA","sub_path":"filament/generic_pla.json"},)"
-        << R"({"name":"Generic PETG","sub_path":"filament/generic_petg.json"}]})";
-    std::ofstream((dirs.system / lib / "filament" / "generic_petg.json").string()) << "{not-json";
-    write_vendor_with_lib_filament(dirs.system, "Acme", "1.0.0");
-    write_vendor_tree(dirs.system, "Zeta", "1.0.0");
-
-    PresetBundle             bundle;
-    std::vector<std::string> failed;
-    const std::string errors = bundle.load_vendors({ { "Acme", dirs.system }, { lib, dirs.system }, { "Zeta", dirs.system } },
-                                                   ForwardCompatibilitySubstitutionRule::EnableSilent,
-                                                   /*allow_cache=*/false, nullptr, &failed).second;
-
-    CHECK(failed == std::vector<std::string>{ lib, "Acme" });
-    CHECK(errors.find("generic_petg.json") != std::string::npos);
-    CHECK(bundle.vendors.count(lib) == 1);
-    CHECK(bundle.vendors.count("Acme") == 0);
-    CHECK(bundle.filaments.find_preset("Acme PLA @0.4", false) == nullptr);
-    CHECK(bundle.vendors.count("Zeta") == 1);
-    CHECK(bundle.prints.find_preset("0.20mm Standard @Zeta", false) != nullptr);
-}
-
-TEST_CASE("a vendor whose profile cannot be read is left out, reported, and the others still load", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_vendor_tree(dirs.system, "Acme", "1.0.0");
-    std::ofstream((dirs.system / "Broken.json").string()) << "{not-json";
-    PresetBundle bundle;
-    const std::string errors = bundle.load_vendors({ { "Acme", dirs.system }, { "Broken", dirs.system } },
-                                                   ForwardCompatibilitySubstitutionRule::EnableSilent,
-                                                   /*allow_cache=*/false).second;
-
-    CHECK(bundle.vendors.count("Acme") == 1);
-    CHECK(bundle.vendors.count("Broken") == 0);
-    CHECK(bundle.prints.find_preset("0.20mm Standard @Acme", false) != nullptr);
-    CHECK(errors.find("Broken.json") != std::string::npos);
-}
-
-TEST_CASE("a canceled vendor load starts no vendor", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_vendor_tree(dirs.system, "Acme", "1.0.0");
-    write_vendor_tree(dirs.system, "Zeta", "1.0.0");
-    const std::atomic<bool> cancel { true };
-    PresetBundle bundle;
-    bundle.load_vendors({ { "Acme", dirs.system }, { "Zeta", dirs.system } },
-                        ForwardCompatibilitySubstitutionRule::EnableSilent, /*allow_cache=*/false, &cancel);
-
-    CHECK(bundle.vendors.empty());
-    CHECK(bundle.prints.find_preset("0.20mm Standard @Acme", false) == nullptr);
-}
-
-TEST_CASE("a preset two vendors both define is kept from the first listed and reported under the others", "[VendorCache]")
-{
-    InstallDirs dirs;
-    for (const std::string vendor : { "Acme", "Mira", "Zeta" })
-        write_process_vendor(dirs.system, vendor, {
-            { "Shared", process_json("Shared", R"("instantiation":"true",)") },
-            { "Own @" + vendor, process_json("Own @" + vendor, R"("instantiation":"true",)") } });
-    PresetBundle bundle;
-    const std::string errors = bundle.load_vendors({ { "Mira", dirs.system }, { "Acme", dirs.system }, { "Zeta", dirs.system } },
-                                                   ForwardCompatibilitySubstitutionRule::EnableSilent,
-                                                   /*allow_cache=*/false).second;
-
-    const Preset* shared = bundle.prints.find_preset("Shared", false);
-    REQUIRE(shared != nullptr);
-    REQUIRE(shared->vendor != nullptr);
-    CHECK(shared->vendor->id == "Mira");
-    CHECK(errors.find("vendor Mira") == std::string::npos);
-    CHECK(errors.find("Found duplicated settings in vendor Acme's json file lists: Shared") != std::string::npos);
-    CHECK(errors.find("Found duplicated settings in vendor Zeta's json file lists: Shared") != std::string::npos);
-    CHECK(bundle.error_count() == 2);
-    for (const std::string vendor : { "Acme", "Mira", "Zeta" }) {
-        const Preset* own = bundle.prints.find_preset("Own @" + vendor, false);
-        REQUIRE(own != nullptr);
-        CHECK(own->vendor == &bundle.vendors.at(vendor));
-    }
-}
-
-TEST_CASE("filaments merged from several vendors come out generic first, then by name", "[VendorCache]")
-{
-    InstallDirs dirs;
-    auto write_filaments = [&](const std::string& vendor, const std::vector<std::string>& names) {
-        fs::create_directories(dirs.system / vendor / "filament");
-        std::ofstream index((dirs.system / (vendor + ".json")).string());
-        index << R"({"version":"1.0.0","name":")" << vendor << R"(","filament_list":[)";
-        for (size_t i = 0; i < names.size(); ++ i) {
-            const std::string sub_path = "filament/f" + std::to_string(i) + ".json";
-            index << (i ? "," : "") << R"({"name":")" << names[i] << R"(","sub_path":")" << sub_path << R"("})";
-            std::ofstream((dirs.system / vendor / sub_path).string())
-                << R"({"type":"filament","name":")" << names[i] << R"(","from":"system","instantiation":"true",)"
-                << R"("filament_id":"GF)" << vendor << i << R"("})";
-        }
-        index << "]}";
-    };
-    write_filaments("Zeta", { "Zeta PLA @0.4", "Generic PETG @Zeta" });
-    write_filaments("Acme", { "Acme PLA @0.4", "Generic PLA @Acme" });
-    PresetBundle bundle;
-    bundle.load_vendors({ { "Zeta", dirs.system }, { "Acme", dirs.system } },
-                        ForwardCompatibilitySubstitutionRule::EnableSilent, /*allow_cache=*/false);
-
-    std::vector<std::string> names;
-    for (const Preset& preset : bundle.filaments.get_presets())
-        if (! preset.is_default)
-            names.push_back(preset.name);
-    CHECK(names == std::vector<std::string>{ "Generic PETG @Zeta", "Generic PLA @Acme", "Acme PLA @0.4", "Zeta PLA @0.4" });
-    for (const std::string& name : names)
-        CHECK(bundle.filaments.find_preset(name, false) != nullptr);
-}
-
-TEST_CASE("a vendor read while the filament library loads resolves against it, from JSON and from its cache", "[VendorCache]")
-{
-    InstallDirs dirs;
-    const std::string lib(PresetBundle::ORCA_FILAMENT_LIBRARY);
-    write_lib_tree(dirs.system, "1.0.0", "20");
-    write_vendor_with_lib_filament(dirs.system, "Acme", "1.0.0");
-    auto load = [&] {
-        auto bundle = std::make_unique<PresetBundle>();
-        bundle->set_generate_vendor_caches(true);
-        bundle->load_vendors({ { "Acme", dirs.system }, { lib, dirs.system } },
-                             ForwardCompatibilitySubstitutionRule::EnableSilent, /*allow_cache=*/true);
-        return bundle;
-    };
-
-    const auto from_json = load();
-    REQUIRE(fs::exists(dirs.system / "Acme.opc"));
-    fs::remove_all(dirs.system / "Acme");
-    const auto from_cache = load();
-
-    for (const PresetBundle* bundle : { from_json.get(), from_cache.get() }) {
-        const Preset* pla = bundle->filaments.find_preset("Acme PLA @0.4", false);
-        REQUIRE(pla != nullptr);
-        CHECK(pla->filament_id == "GFL99");
-        CHECK_THAT(pla->config.option<ConfigOptionFloats>("filament_cost")->values.front(), WithinAbs(20., 1e-9));
-        CHECK(bundle->error_count() == 0);
-    }
-}
-
-TEST_CASE("repeated cache loads of one vendor produce the same presets", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_filament_list(dirs.system, "Acme", write_layered_filaments(dirs.system, "Acme", 400));
-
-    PresetBundle seed;
-    seed.set_generate_vendor_caches(true);
-    seed.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                       ForwardCompatibilitySubstitutionRule::EnableSilent);
-    REQUIRE(fs::exists(dirs.system / "Acme.opc"));
-    fs::remove_all(dirs.system / "Acme");
-
-    std::vector<PresetBundle> loads(3);
-    for (PresetBundle& bundle : loads)
-        bundle.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                             ForwardCompatibilitySubstitutionRule::EnableSilent);
-
-    auto first = presets_for(loads[0].filaments, "Acme");
-    REQUIRE(!first.empty());
-    for (size_t run = 1; run < loads.size(); ++ run) {
-        auto again = presets_for(loads[run].filaments, "Acme");
-        REQUIRE(again.size() == first.size());
-        for (size_t i = 0; i < first.size(); ++ i) {
-            CHECK(first[i]->name == again[i]->name);
-            CHECK(preset_deep_equal(*first[i], *again[i]));
-        }
-        CHECK(loads[run].error_count() == loads[0].error_count());
-    }
-}
-
 TEST_CASE("a cache-served vendor reports the errors its parse counted", "[VendorCache]")
 {
     TempDir tmp;
@@ -1263,27 +866,6 @@ TEST_CASE("a vendor installed as its cache alone still loads after a library upd
     CHECK_THAT(cost->values.front(), WithinAbs(30., 1e-9));
 }
 
-TEST_CASE("a cache install stopped by a canceled task group throws instead of rejecting the cache", "[VendorCache]")
-{
-    TempDir tmp;
-    const std::string cache = (tmp.path / "Acme.opc").string();
-    REQUIRE(save_one_vendor(cache, one_vendor("Acme"), "Acme", "1.0.0", {filament_entry("Acme PLA @0.4")}));
-
-    PresetBundle            bundle;
-    bool                    threw = false;
-    tbb::task_group_context context;
-    tbb::parallel_for(tbb::blocked_range<size_t>(0, 1), [&](const tbb::blocked_range<size_t>&) {
-        context.cancel_group_execution();
-        try {
-            bundle.load_vendor_cache(cache, "Acme", Semver(1, 0, 0));
-        } catch (const std::runtime_error&) {
-            threw = true;
-        }
-    }, context);
-
-    CHECK(threw);
-}
-
 TEST_CASE("a cache entry whose parent is missing falls back to the vendor's JSONs", "[VendorCache]")
 {
     TempDir tmp;
@@ -1311,12 +893,6 @@ TEST_CASE("a cache entry whose parent is missing falls back to the vendor's JSON
         user.string(), "Acme", PresetBundle::LoadSystem, ForwardCompatibilitySubstitutionRule::EnableSilent);
     CHECK(presets_loaded == 1);
     CHECK(out.vendors.at("Acme").name == "Acme");   // the profile's name, not the cache's
-
-    // Through load_vendors, which reads the cache before installing it.
-    PresetBundle several;
-    several.load_vendors({ { "Acme", user } }, ForwardCompatibilitySubstitutionRule::EnableSilent, /*allow_cache=*/true);
-    CHECK(several.vendors.at("Acme").name == "Acme");
-    CHECK(several.prints.find_preset("0.20mm Standard @Acme", false) != nullptr);
 }
 
 TEST_CASE("a profile with no usable version is never served from cache", "[VendorCache]")
@@ -1804,6 +1380,24 @@ TEST_CASE("a header claiming more body than the file holds is rejected", "[Vendo
     REQUIRE_FALSE(bundle.load_vendor_cache(cache, "Bounded", Semver(1, 0, 0)));
 }
 
+TEST_CASE("a failed write leaves the previous cache in place", "[VendorCache]")
+{
+    TempDir tmp;
+    const std::string cache = (tmp.path / "Durable.opc").string();
+    REQUIRE(save_one_vendor(cache, one_vendor("Durable"), "Durable", "1.0.0"));
+    const std::string before = slurp(cache);
+
+    // A directory where the temp file wants to go: the write cannot complete,
+    // and must not have destroyed what was already there to find that out.
+    const fs::path blocker = fs::path(cache + "." + std::to_string(get_current_pid()) + ".tmp");
+    fs::create_directories(blocker);
+
+    REQUIRE_FALSE(save_one_vendor(cache, one_vendor("Durable"), "Durable", "2.0.0"));
+    CHECK(slurp(cache) == before);
+
+    fs::remove_all(blocker);
+}
+
 TEST_CASE("a cache written by another build's option ordering still loads", "[VendorCache]")
 {
     // The regression the fingerprint used to prevent by refusing the file
@@ -2097,31 +1691,6 @@ TEST_CASE("an include listed after the preset that names it is an error, and the
     CHECK(silk->config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->values == std::vector<double>{12.});
 }
 
-TEST_CASE("an include listed after the preset that names it is missing from the cache load too", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_full_vendor_tree(dirs.system, "Acme", "1.0.0", /*templates_last=*/true);
-    PresetBundle from_json;
-    from_json.set_generate_vendor_caches(true);
-    from_json.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                            ForwardCompatibilitySubstitutionRule::EnableSilent);
-    REQUIRE(fs::exists(dirs.system / "Acme.opc"));
-
-    fs::remove_all(dirs.system / "Acme");
-    PresetBundle from_cache;
-    from_cache.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                             ForwardCompatibilitySubstitutionRule::EnableSilent);
-    CHECK(from_cache.error_count() == 2);
-    const Preset* pr = from_cache.printers.find_preset("Acme 0.4 nozzle", false);
-    REQUIRE(pr != nullptr);
-    CHECK(pr->config.opt_string("machine_start_gcode") != "G28 ; template");
-    const Preset* silk = from_cache.filaments.find_preset("Acme Silk PLA @0.4", false);
-    REQUIRE(silk != nullptr);
-    const auto& speed = silk->config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->values;
-    REQUIRE(speed.size() == 1);
-    CHECK_THAT(speed.front(), WithinAbs(12., 1e-9));
-}
-
 TEST_CASE("a G-code template that states no instantiation is included, not loaded as a preset", "[VendorCache]")
 {
     InstallDirs dirs;
@@ -2143,35 +1712,3 @@ TEST_CASE("a G-code template that states no instantiation is included, not loade
     CHECK(pr->config.opt_string("machine_start_gcode") == "G28 ; template");
     CHECK(presets_for(bundle.printers, "Acme").size() == 1);
 }
-
-TEST_CASE("a sub-file that fails to parse leaves the ones listed before it installed", "[VendorCache]")
-{
-    InstallDirs dirs;
-    write_process_vendor(dirs.system, "Acme", {
-        { "Acme A", process_json("Acme A", R"("instantiation":"true",)") },
-        { "Acme B", "{not-json" },
-        { "Acme C", process_json("Acme C", R"("instantiation":"true",)") } });
-    PresetBundle bundle;
-    CHECK_THROWS_AS(bundle.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                                         ForwardCompatibilitySubstitutionRule::EnableSilent),
-                    ConfigurationError);
-    CHECK(bundle.prints.find_preset("Acme A", false) != nullptr);
-    CHECK(bundle.prints.find_preset("Acme C", false) == nullptr);
-}
-
-TEST_CASE("a load that fails to install partway counts no errors of the sub-files after it", "[VendorCache]")
-{
-    InstallDirs dirs;
-    // B names a parent nobody defines. C states no instantiation, an error of its own.
-    write_process_vendor(dirs.system, "Acme", {
-        { "Acme A", process_json("Acme A", R"("instantiation":"true",)") },
-        { "Acme B", process_json("Acme B", R"("instantiation":"true","inherits":"Nobody",)") },
-        { "Acme C", process_json("Acme C") } });
-    PresetBundle bundle;
-    CHECK_THROWS_AS(bundle.load_vendor_configs_from_json(dirs.system.string(), "Acme", PresetBundle::LoadSystem,
-                                                         ForwardCompatibilitySubstitutionRule::EnableSilent),
-                    ConfigurationError);
-    // B's missing parent and B's failed install.
-    CHECK(bundle.error_count() == 2);
-    CHECK(bundle.prints.find_preset("Acme A", false) != nullptr);
-}