feat: initial draft of lifecycle events API for plugins

src/libslic3r/GCode.cpp

@@ -7,6 +7,7 @@
 #include "I18N.hpp"
 #include "GCode.hpp"
 #include "Exception.hpp"
+#include "LifecycleEvents.hpp"
 #include "ExtrusionEntity.hpp"
 #include "EdgeGrid.hpp"
 #include "Geometry/ConvexHull.hpp"
@@ -2446,6 +2447,13 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessorResult* resu
     m_writer.set_is_bbl_machine(print->is_BBL_printer());
     print->set_started(psGCodeExport);
 
+    {
+        LifecycleEventContext ctx;
+        ctx.name = path;
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::GCodeExportStarted, ctx);
+    }
+
     // check if any custom gcode contains keywords used by the gcode processor to
     // produce time estimation and gcode toolpaths
     std::vector<std::pair<std::string, std::string>> validation_res = DoExport::validate_custom_gcode(*print);
@@ -2481,12 +2489,22 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessorResult* resu
     m_processor.set_print(print);
     GCodeOutputStream file(boost::nowide::fopen(path_tmp.c_str(), "wb"), m_processor);
     if (! file.is_open()) {
-        BOOST_LOG_TRIVIAL(error) << std::string("G-code export to ") + path + " failed.\nCannot open the file for writing.\n" << std::endl;
+        std::string err_msg = std::string("G-code export to ") + path + " failed.\nCannot open the file for writing.\n";
+        BOOST_LOG_TRIVIAL(error) << err_msg << std::endl;
         if (!fs::exists(folder)) {
             //fs::create_directory(folder);
-            BOOST_LOG_TRIVIAL(error) << "the parent path " + folder.string() +" is not there!!!" << std::endl;
+            std::string add_err_msg = "the parent path " + folder.string() +" is not there!!!";
+            BOOST_LOG_TRIVIAL(error) << add_err_msg << std::endl;
+            err_msg += add_err_msg;
         }
-        throw Slic3r::RuntimeError(std::string("G-code export to ") + path + " failed.\nCannot open the file for writing.\n");
+        {
+            LifecycleEventContext ctx;
+            ctx.name = path;
+            ctx.code = LifecycleEvtCode::Error;
+            ctx.msg  = err_msg;
+            fire_lifecycle_event(LifecycleEvent::GCodeExportFinished, ctx);
+        }
+        throw Slic3r::RuntimeError(err_msg);
     }
 
     try {
@@ -2497,11 +2515,18 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessorResult* resu
             boost::nowide::remove(path_tmp.c_str());
             throw Slic3r::RuntimeError(std::string("G-code export to ") + path + " failed\nIs the disk full?\n");
         }
-    } catch (std::exception & /* ex */) {
+    } catch (std::exception &ex) {
         // Rethrow on any exception. std::runtime_exception and CanceledException are expected to be thrown.
         // Close and remove the file.
         file.close();
         boost::nowide::remove(path_tmp.c_str());
+        {
+            LifecycleEventContext ctx;
+            ctx.name = path;
+            ctx.code = LifecycleEvtCode::Error;
+            ctx.msg  = ex.what();
+            fire_lifecycle_event(LifecycleEvent::GCodeExportFinished, ctx);
+        }
         throw;
     }
     file.close();
@@ -2607,6 +2632,13 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessorResult* resu
 
     std::error_code ret = rename_file(path_tmp, path);
     if (ret) {
+        {
+            LifecycleEventContext ctx;
+            ctx.name = path;
+            ctx.code = LifecycleEvtCode::Error;
+            ctx.msg  = "Failed to rename the output G-code file: " + ret.message();
+            fire_lifecycle_event(LifecycleEvent::GCodeExportFinished, ctx);
+        }
         throw Slic3r::RuntimeError(
             std::string("Failed to rename the output G-code file from ") + path_tmp + " to " + path + '\n' + "error code " + ret.message() + '\n' +
             "Is " + path_tmp + " locked?" + '\n');
@@ -2618,6 +2650,13 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessorResult* resu
     BOOST_LOG_TRIVIAL(info) << "Exporting G-code finished" << log_memory_info();
     print->set_done(psGCodeExport);
 
+    {
+        LifecycleEventContext ctx;
+        ctx.name = path;
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::GCodeExportFinished, ctx);
+    }
+
     // Orca: label_object_enabled reflects whether objects are labeled in the g-code (EXCLUDE_OBJECT /
     // M486), which is driven by exclude_object for every printer
     if(result != nullptr)

src/libslic3r/LifecycleEvents.hpp

@@ -0,0 +1,135 @@
+#pragma once
+
+// LifecycleEvents.hpp
+// --------------------
+// Application lifecycle events (project, slicing, plate editing, preset, printer connection
+// activity) that other subsystems -- chiefly the plugin layer above libslic3r -- may want to
+// observe. Lives in libslic3r rather than the plugin layer because some events fire from inside
+// the slicing engine itself; see fire_lifecycle_event() below.
+
+#include <functional>
+#include <string>
+#include <utility>
+
+namespace Slic3r
+{
+    enum class LifecycleEvent {
+        // Project (3mf)
+        NewProject,
+        ProjectOpened,
+        ProjectBeforeSave,
+        ProjectAfterSave,
+        ProjectClosed,
+
+        // Slicing pipeline
+        SliceStarted,
+        SliceGeometryFinished,
+        GCodeExportStarted,
+        GCodeExportFinished,
+        SlicingJobComplete,
+
+        // Plate/model editing
+        ObjectAdded,
+        ObjectDeleted,
+        ObjectTransformed,
+
+        // Preset
+        PresetSelected,
+        PresetSaved,
+
+        // Printer/device
+        PrintStateChanged,
+        DeviceOnlineChanged,
+        DeviceDiscovered,
+        DeviceSelected,
+        DeviceConnected,
+        DeviceDisconnected,
+        UploadStarted,
+        UploadFinished,
+    };
+
+    // Scoped so callers must qualify (LifecycleEvtCode::Error, not ERROR) -- ERROR/OK collide with
+    // Windows macros (wingdi.h) as unqualified names.
+    enum class LifecycleEvtCode { Ok, Error, Warn };
+
+    struct LifecycleEventContext
+    {
+        // The primary subject identifier for the event. This is event-specific (for example, a
+        // project/output path, preset name, device id, or object name), must not contain status or
+        // prose, and may be empty when the event has no single subject.
+        std::string name;
+
+        // Outcome of the operation represented by the event. For state-change and start events,
+        // Ok means that the event occurred; it does not imply that a future operation succeeded.
+        LifecycleEvtCode code = LifecycleEvtCode::Ok;
+
+        // Optional human-readable detail or diagnostic text. It is not a stable parsing contract;
+        // machine-readable data should be represented by a dedicated field or event instead.
+        std::string msg;
+    };
+
+    inline std::string lifecycle_event_to_string(LifecycleEvent event)
+    {
+        switch (event) {
+        case LifecycleEvent::NewProject: return "NewProject";
+        case LifecycleEvent::ProjectOpened: return "ProjectOpened";
+        case LifecycleEvent::ProjectBeforeSave: return "ProjectBeforeSave";
+        case LifecycleEvent::ProjectAfterSave: return "ProjectAfterSave";
+        case LifecycleEvent::ProjectClosed: return "ProjectClosed";
+
+        case LifecycleEvent::SliceStarted: return "SliceStarted";
+        case LifecycleEvent::SliceGeometryFinished: return "SliceGeometryFinished";
+        case LifecycleEvent::GCodeExportStarted: return "GCodeExportStarted";
+        case LifecycleEvent::GCodeExportFinished: return "GCodeExportFinished";
+        case LifecycleEvent::SlicingJobComplete: return "SlicingJobComplete";
+
+        case LifecycleEvent::ObjectAdded: return "ObjectAdded";
+        case LifecycleEvent::ObjectDeleted: return "ObjectDeleted";
+        case LifecycleEvent::ObjectTransformed: return "ObjectTransformed";
+
+        case LifecycleEvent::PresetSelected: return "PresetSelected";
+        case LifecycleEvent::PresetSaved: return "PresetSaved";
+        case LifecycleEvent::PrintStateChanged: return "PrintStateChanged";
+
+        case LifecycleEvent::DeviceOnlineChanged: return "DeviceOnlineChanged";
+        case LifecycleEvent::DeviceDiscovered: return "DeviceDiscovered";
+        case LifecycleEvent::DeviceSelected: return "DeviceSelected";
+        case LifecycleEvent::DeviceConnected: return "DeviceConnected";
+        case LifecycleEvent::DeviceDisconnected: return "DeviceDisconnected";
+
+        case LifecycleEvent::UploadStarted: return "UploadStarted";
+        case LifecycleEvent::UploadFinished: return "UploadFinished";
+        default: return "Unknown";
+        }
+    }
+
+    inline std::string lifecycle_evt_code_to_string(LifecycleEvtCode code)
+    {
+        switch (code) {
+        case LifecycleEvtCode::Ok: return "Ok";
+        case LifecycleEvtCode::Error: return "Error";
+        case LifecycleEvtCode::Warn: return "Warn";
+        default: return "Unknown";
+        }
+    }
+
+    // Global cross-layer seam (mirrors ConfigBase::set_resolve_capability_fn): any libslic3r code can
+    // fire a lifecycle event without depending on the plugin layer above it, which installs the
+    // dispatcher here at startup. Not tied to Print/GCode specifically, since nothing here should
+    // require callers to hold a Print& just to report an event.
+    using LifecycleHookFn = std::function<void(LifecycleEvent, const LifecycleEventContext&)>;
+
+    inline LifecycleHookFn& lifecycle_hook_fn()
+    {
+        static LifecycleHookFn fn;
+        return fn;
+    }
+
+    inline void set_lifecycle_hook_fn(LifecycleHookFn fn) { lifecycle_hook_fn() = std::move(fn); }
+
+    inline void fire_lifecycle_event(LifecycleEvent event, const LifecycleEventContext& ctx)
+    {
+        if (const LifecycleHookFn& fn = lifecycle_hook_fn(); fn)
+            fn(event, ctx);
+    }
+}

src/libslic3r/Preset.cpp

@@ -45,6 +45,7 @@
 #include <boost/log/trivial.hpp>
 
 #include "libslic3r.h"
+#include "LifecycleEvents.hpp"
 #include "Utils.hpp"
 #include "Time.hpp"
 #include "PlaceholderParser.hpp"
@@ -2931,6 +2932,7 @@ void PresetCollection::save_current_preset(const std::string &new_name, bool det
     // 1) Find the preset with a new_name or create a new one,
     // initialize it with the edited config.
     auto it = this->find_preset_internal(new_name);
+    const bool preset_existed = (it != m_presets.end() && it->name == new_name);
     if (it != m_presets.end() && it->name == new_name) {
         // Preset with the same name found.
         Preset &preset = *it;
@@ -3038,6 +3040,14 @@ void PresetCollection::save_current_preset(const std::string &new_name, bool det
         this->get_selected_preset().save(&(parent_preset->config));
     else
         this->get_selected_preset().save(nullptr);
+
+    {
+        LifecycleEventContext ctx;
+        ctx.name  = new_name;
+        ctx.msg = preset_existed ? "overwrite" : "new";
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::PresetSaved, ctx);
+    }
 }
 
 bool PresetCollection::delete_current_preset()

src/libslic3r/Print.cpp

@@ -8,6 +8,7 @@
 #include "Flow.hpp"
 #include "Geometry/ConvexHull.hpp"
 #include "I18N.hpp"
+#include "LifecycleEvents.hpp"
 #include "ShortestPath.hpp"
 #include "Thread.hpp"
 #include "Time.hpp"
@@ -2252,6 +2253,13 @@ void Print::process(long long *time_cost_with_cache, bool use_cache)
     if (m_objects.empty())
         return;
 
+    {
+        LifecycleEventContext ctx;
+        ctx.name = output_filename();
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::SliceStarted, ctx);
+    }
+
     for (PrintObject *obj : m_objects)
         obj->clear_shared_object();
 
@@ -2818,6 +2826,13 @@ void Print::process(long long *time_cost_with_cache, bool use_cache)
     }
 
     BOOST_LOG_TRIVIAL(info) << "Slicing process finished." << log_memory_info();
+
+    {
+        LifecycleEventContext ctx;
+        ctx.code = LifecycleEvtCode::Ok;
+        ctx.name = output_filename();
+        fire_lifecycle_event(LifecycleEvent::SliceGeometryFinished, ctx);
+    }
 }
 
 // G-code export process, running at a background thread.
@@ -4434,6 +4449,13 @@ void Print::set_gcode_file_invalidated()
 //BBS: add gcode file preload logic
 void Print::export_gcode_from_previous_file(const std::string& file, GCodeProcessorResult* result, ThumbnailsGeneratorCallback thumbnail_cb)
 {
+    {
+        LifecycleEventContext ctx;
+        ctx.name = file;
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::GCodeExportStarted, ctx);
+    }
+
     try {
         GCodeProcessor processor;
         GCodeProcessor::s_IsBBLPrinter = is_BBL_printer();
@@ -4453,13 +4475,27 @@ void Print::export_gcode_from_previous_file(const std::string& file, GCodeProces
         *result = std::move(processor.extract_result());
         result->filament_change_sequence = filament_seq_loaded;
         result->nozzle_change_sequence   = nozzle_seq_loaded;
-    } catch (std::exception & /* ex */) {
+    } catch (std::exception &ex) {
         BOOST_LOG_TRIVIAL(error) << __FUNCTION__ <<  boost::format(": found errors when process gcode file %1%") %file.c_str();
+        {
+            LifecycleEventContext ctx;
+            ctx.name = file;
+            ctx.code = LifecycleEvtCode::Error;
+            ctx.msg  = ex.what();
+            fire_lifecycle_event(LifecycleEvent::GCodeExportFinished, ctx);
+        }
         throw Slic3r::RuntimeError(
             std::string("Failed to process the G-code file ") + file + " from previous 3mf\n");
     }
 
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ <<  boost::format(":  process the G-code file %1% successfully")%file.c_str();
+
+    {
+        LifecycleEventContext ctx;
+        ctx.name = file;
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::GCodeExportFinished, ctx);
+    }
 }
 
 std::tuple<float, float> Print::object_skirt_offset(double margin_height) const

src/slic3r/GUI/DeviceCore/DevManager.cpp

@@ -10,6 +10,7 @@
 #include "slic3r/GUI/I18N.hpp"
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/Plater.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 
 #include "libslic3r/Time.hpp"
 
@@ -328,7 +329,10 @@ namespace Slic3r
                     obj->bind_state = "free";
 
                 obj->last_alive = Slic3r::Utils::get_current_time_utc();
-                obj->m_is_online = true;
+                // Route through set_online_state() (rather than writing m_is_online directly) so the
+                // DeviceOnlineChanged lifecycle event fires consistently; same effective value/behavior
+                // here since the object was already online in the common case.
+                obj->set_online_state(true);
                 obj->set_dev_name(dev_name);
                 /* if (!obj->dev_ip.empty()) {
                 Slic3r::GUI::wxGetApp().app_config->set_str("ip_address", obj->dev_id, obj->dev_ip);
@@ -345,6 +349,10 @@ namespace Slic3r
                 obj->bind_sec_link  = sec_link;
                 obj->dev_connection_name = connection_name;
                 obj->bind_ssdp_version = ssdp_version;
+                // Discovery establishes the initial reachability state. Do not report it as an
+                // online transition; DeviceDiscovered below is the lifecycle event for a new
+                // device. Subsequent updates route through set_online_state(), so a known device
+                // still emits DeviceOnlineChanged when its reachability actually changes.
                 obj->m_is_online = true;
 
                 //load access code
@@ -361,6 +369,15 @@ namespace Slic3r
                 BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << " New Machine, dev_id= " << dev_id
                     << ", ip = " << dev_ip <<", printer_name = " << dev_name
                     << ", con_type= " << connect_type <<", signal= " << printer_signal << ", bind_state= " << bind_state;
+
+                // First discovery of a genuinely new device (not a periodic SSDP/heartbeat update to
+                // an already-known one, which is handled in the branch above).
+                {
+                    LifecycleEventContext ctx;
+                    ctx.name = dev_id;
+                    ctx.code = LifecycleEvtCode::Ok;
+                    fire_lifecycle_event(LifecycleEvent::DeviceDiscovered, ctx);
+                }
             }
             update_local_machine(*obj);
         }
@@ -935,8 +952,14 @@ namespace Slic3r
     }
 
     void DeviceManager::OnSelectedMachineChanged(const std::string& /*pre_dev_id*/,
-                                                 const std::string& /*new_dev_id*/)
+                                                 const std::string& new_dev_id)
     {
+        {
+            LifecycleEventContext ctx;
+            ctx.name = new_dev_id; // empty string is a valid deselection
+            ctx.code = LifecycleEvtCode::Ok;
+            fire_lifecycle_event(LifecycleEvent::DeviceSelected, ctx);
+        }
         if (MachineObject* obj_ = get_selected_machine()) {
             GUI::wxGetApp().sidebar().update_sync_status(obj_);
             if(m_agent->get_filament_sync_mode() == FilamentSyncMode::subscription)

src/slic3r/GUI/DeviceManager.cpp

@@ -3,6 +3,7 @@
 #include "libslic3r/Time.hpp"
 #include "libslic3r/Thread.hpp"
 #include "slic3r/Utils/NetworkAgent.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 #include "GuiColor.hpp"
 
 #include "GUI_App.hpp"
@@ -2591,7 +2592,15 @@ void MachineObject::reset()
 
 void MachineObject::set_print_state(std::string status)
 {
+    const bool changed = (print_status != status);
     print_status = status;
+    if (changed) {
+        LifecycleEventContext ctx;
+        ctx.name  = dev_id;
+        ctx.code  = LifecycleEvtCode::Ok;
+        ctx.msg   = print_status;
+        fire_lifecycle_event(LifecycleEvent::PrintStateChanged, ctx);
+    }
 }
 
 int MachineObject::connect(bool use_openssl)
@@ -2613,6 +2622,10 @@ int MachineObject::connect(bool use_openssl)
 int MachineObject::disconnect()
 {
     if (m_agent) {
+        LifecycleEventContext ctx;
+        ctx.name = dev_id;
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::DeviceDisconnected, ctx);
         return m_agent->disconnect_printer();
     }
     return -1;
@@ -2643,8 +2656,16 @@ bool MachineObject::is_connecting()
 
 void MachineObject::set_online_state(bool on_off)
 {
+    const bool changed = (m_is_online != on_off);
     m_is_online = on_off;
     if (!on_off) m_active_state = NotActive;
+    if (changed) {
+        LifecycleEventContext ctx;
+        ctx.name  = dev_id;
+        ctx.code  = LifecycleEvtCode::Ok;
+        ctx.msg   = on_off ? "online" : "offline";
+        fire_lifecycle_event(LifecycleEvent::DeviceOnlineChanged, ctx);
+    }
 }
 
 bool MachineObject::is_info_ready(bool check_version) const
@@ -4566,8 +4587,13 @@ int MachineObject::parse_json(std::string tunnel, std::string payload, bool key_
         try {
             if (j.contains("event")) {
                 if (j["event"].contains("event")) {
-                    if (j["event"]["event"].get<std::string>() == "client.disconnected")
+                    if (j["event"]["event"].get<std::string>() == "client.disconnected") {
                         set_online_state(false);
+                        LifecycleEventContext ctx;
+                        ctx.name = dev_id;
+                        ctx.code = LifecycleEvtCode::Ok;
+                        fire_lifecycle_event(LifecycleEvent::DeviceDisconnected, ctx);
+                    }
                     else if (j["event"]["event"].get<std::string>() == "client.connected")
                         set_online_state(true);
                 }

src/slic3r/GUI/GLCanvas3D.cpp

@@ -39,6 +39,7 @@
 #include "slic3r/GUI/Gizmos/GLGizmoPainterBase.hpp"
 #include "slic3r/Utils/UndoRedo.hpp"
 #include "slic3r/Utils/MacDarkMode.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 
 #include <slic3r/GUI/GUI_Utils.hpp>
 
@@ -5061,8 +5062,16 @@ void GLCanvas3D::do_move(const std::string& snapshot_type)
     //BBS: nofity object list to update
     wxGetApp().plater()->sidebar().obj_list()->update_plate_values_for_items();
 
-    if (object_moved)
+    if (object_moved) {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        ctx.msg = "moved";
+        if (done.size() == 1)
+            ctx.name = m_model->objects[done.begin()->first]->name;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectTransformed, ctx);
+
         post_event(SimpleEvent(EVT_GLCANVAS_INSTANCE_MOVED));
+    }
 
     // BBS: support wipe-tower for multi-plates
     for (int plate_id = 0; plate_id < wipe_tower_origins.size(); plate_id++) {
@@ -5183,8 +5192,16 @@ void GLCanvas3D::do_rotate(const std::string& snapshot_type)
     //BBS: nofity object list to update
     wxGetApp().plater()->sidebar().obj_list()->update_plate_values_for_items();
 
-    if (!done.empty())
+    if (!done.empty()) {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        ctx.msg = "rotated";
+        if (done.size() == 1)
+            ctx.name = m_model->objects[done.begin()->first]->name;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectTransformed, ctx);
+
         post_event(SimpleEvent(EVT_GLCANVAS_INSTANCE_ROTATED));
+    }
 
     m_dirty = true;
 }
@@ -5275,8 +5292,16 @@ void GLCanvas3D::do_scale(const std::string& snapshot_type)
     //BBS: notify object info update
     wxGetApp().plater()->show_object_info();
 
-    if (!done.empty())
+    if (!done.empty()) {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        ctx.msg = "scaled";
+        if (done.size() == 1)
+            ctx.name = m_model->objects[done.begin()->first]->name;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectTransformed, ctx);
+
         post_event(SimpleEvent(EVT_GLCANVAS_INSTANCE_SCALED));
+    }
 
     m_dirty = true;
 }

src/slic3r/GUI/GUI_App.cpp

@@ -2169,6 +2169,11 @@ void GUI_App::init_networking_callbacks()
                     obj->command_get_access_code();
                     if (m_agent)
                         m_agent->install_device_cert(obj->get_dev_id(), obj->is_lan_mode_printer());
+
+                    LifecycleEventContext ctx;
+                    ctx.name = obj->get_dev_id();
+                    ctx.code = LifecycleEvtCode::Ok;
+                    fire_lifecycle_event(LifecycleEvent::DeviceConnected, ctx);
                 }
                 });
             });
@@ -2207,6 +2212,11 @@ void GUI_App::init_networking_callbacks()
                                 obj->command_get_version();
                                 event.SetInt(0);
                                 event.SetString(obj->get_dev_id());
+
+                                LifecycleEventContext ctx;
+                                ctx.name = obj->get_dev_id();
+                                ctx.code = LifecycleEvtCode::Ok;
+                                fire_lifecycle_event(LifecycleEvent::DeviceConnected, ctx);
                             } else if (state == ConnectStatus::ConnectStatusFailed) {
                                 // Orca: only update status if same device id
                                 if (m_device_manager->selected_machine != dev_id) return;
@@ -2222,10 +2232,22 @@ void GUI_App::init_networking_callbacks()
                                     wxGetApp().show_dialog(text);
                                 }
                                 event.SetInt(-1);
+
+                                {
+                                    LifecycleEventContext ctx;
+                                    ctx.name = dev_id;
+                                    ctx.code = LifecycleEvtCode::Ok;
+                                    fire_lifecycle_event(LifecycleEvent::DeviceDisconnected, ctx);
+                                }
                             } else if (state == ConnectStatus::ConnectStatusLost) {
                                 m_device_manager->set_selected_machine("");
                                 event.SetInt(-1);
                                 BOOST_LOG_TRIVIAL(info) << "set_on_local_connect_fn: state = lost";
+
+                                LifecycleEventContext ctx;
+                                ctx.name = dev_id;
+                                ctx.code = LifecycleEvtCode::Ok;
+                                fire_lifecycle_event(LifecycleEvent::DeviceDisconnected, ctx);
                             } else {
                                 event.SetInt(-1);
                                 BOOST_LOG_TRIVIAL(info) << "set_on_local_connect_fn: state = " << state;

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -9,6 +9,7 @@
 #include "BitmapComboBox.hpp"
 #include "MainFrame.hpp"
 #include "slic3r/Utils/UndoRedo.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 
 #include "OptionsGroup.hpp"
 #include "Tab.hpp"
@@ -3530,7 +3531,14 @@ void ObjectList::delete_all_connectors_for_object(int obj_idx)
             obj->delete_connectors();
 
             if (obj->volumes.empty() || !obj->has_solid_mesh()) {
+                const std::string deleted_obj_name = obj->name;
                 model.delete_object(idx);
+                {
+                    Slic3r::LifecycleEventContext ctx;
+                    ctx.name = deleted_obj_name;
+                    ctx.code = Slic3r::LifecycleEvtCode::Ok;
+                    Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectDeleted, ctx);
+                }
                 m_objects_model->Delete(m_objects_model->GetItemById(idx));
                 continue;
             }
@@ -4099,6 +4107,13 @@ void ObjectList::add_object_to_list(size_t obj_idx, bool call_selection_changed,
     const auto item = m_objects_model->AddObject(model_object, warning_bitmap, model_object->is_cut());
     Expand(m_objects_model->GetParent(item));
 
+    {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.name = model_object->name;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectAdded, ctx);
+    }
+
     if (!do_info_update)
         return;
 

src/slic3r/GUI/Jobs/ArrangeJob.cpp

@@ -13,6 +13,7 @@
 #include "slic3r/GUI/NotificationManager.hpp"
 #include "slic3r/GUI/format.hpp"
 #include "slic3r/GUI/GUI_ObjectList.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 
 #include "libnest2d/common.hpp"
 
@@ -699,6 +700,13 @@ void ArrangeJob::finalize(bool canceled, std::exception_ptr &eptr) {
         BOOST_LOG_TRIVIAL(debug) << __FUNCTION__ << boost::format(":arrange m_unprintable: name: %4%, bed_id %1%, trans {%2%,%3%}") % ap.bed_idx % unscale<double>(ap.translation(X)) % unscale<double>(ap.translation(Y)) % ap.name;
     }
 
+    {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        ctx.msg = "arranged";
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectTransformed, ctx);
+    }
+
     m_plater->update();
     // BBS
     //wxGetApp().obj_manipul()->set_dirty();

src/slic3r/GUI/Jobs/FillBedJob.cpp

@@ -6,6 +6,7 @@
 #include "slic3r/GUI/Plater.hpp"
 #include "slic3r/GUI/GLCanvas3D.hpp"
 #include "slic3r/GUI/GUI_ObjectList.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 #include "libnest2d/common.hpp"
 
 #include <numeric>
@@ -347,6 +348,13 @@ void FillBedJob::finalize(bool canceled, std::exception_ptr &eptr)
             m_plater->arrange();
         }
         m_plater->update();
+
+        {
+            Slic3r::LifecycleEventContext ctx;
+            ctx.code = Slic3r::LifecycleEvtCode::Ok;
+            ctx.msg = "arranged";
+            Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectTransformed, ctx);
+        }
     }
 
     m_plater->mark_plate_toolbar_image_dirty();

src/slic3r/GUI/Jobs/OrientJob.cpp

@@ -5,6 +5,7 @@
 #include "slic3r/GUI/GUI.hpp"
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/NotificationManager.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 #include "libslic3r/PresetBundle.hpp"
 
 
@@ -254,6 +255,12 @@ void OrientJob::finalize(bool canceled, std::exception_ptr &eptr)
         mesh.apply();
     }
 
+    if (!m_selected.empty()) {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        ctx.msg = "auto_oriented";
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectTransformed, ctx);
+    }
 
     m_plater->update();
 

src/slic3r/GUI/Plater.cpp

@@ -8375,7 +8375,14 @@ void Plater::priv::remove(size_t obj_idx)
         view3D->enable_layers_editing(false);
 
     m_worker.cancel_all();
+    std::string obj_name = (obj_idx < model.objects.size()) ? model.objects[obj_idx]->name : std::to_string(obj_idx);
     model.delete_object(obj_idx);
+    {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.name = obj_name;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectDeleted, ctx);
+    }
     //BBS: notify partplate the instance removed
     partplate_list.notify_instance_removed(obj_idx, -1);
     update();
@@ -8408,7 +8415,14 @@ bool Plater::priv::delete_object_from_model(size_t obj_idx, bool refresh_immedia
     if (obj->is_cut())
         sidebar->obj_list()->invalidate_cut_info_for_object(obj_idx);
 
+    std::string obj_name = obj->name;
     model.delete_object(obj_idx);
+    {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.name = obj_name;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ObjectDeleted, ctx);
+    }
     //BBS: notify partplate the instance removed
     partplate_list.notify_instance_removed(obj_idx, -1);
 
@@ -8458,6 +8472,14 @@ void Plater::priv::reset(bool apply_presets_change)
 
     clear_warnings();
 
+    const std::string closed_project_name = into_u8(get_project_filename());
+    if (!closed_project_name.empty() || !model.objects.empty()) {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.name = closed_project_name;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ProjectClosed, ctx);
+    }
+
     set_project_filename("");
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << __LINE__ << " call set_project_filename: empty";
 
@@ -10868,11 +10890,15 @@ void Plater::priv::on_process_completed(SlicingProcessCompletedEvent &evt)
     notification_manager->set_slicing_progress_export_possible();
 
     // Reset the "export G-code path" name, so that the automatic background processing will be enabled again.
+    const std::string lifecycle_job_name = this->background_process.fff_print() ?
+        this->background_process.fff_print()->output_filename() : std::string();
     this->background_process.reset_export();
     // This bool stops showing export finished notification even when process_completed_with_error is false
     bool has_error = false;
+    std::string lifecycle_error_msg;
     if (evt.error()) {
         auto message = evt.format_error_message();
+        lifecycle_error_msg = message.first;
         if (evt.critical_error()) {
             if (q->m_tracking_popup_menu) {
                 // We don't want to pop-up a message box when tracking a pop-up menu.
@@ -10910,6 +10936,14 @@ void Plater::priv::on_process_completed(SlicingProcessCompletedEvent &evt)
         is_finished = true;
     }
 
+    {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.name = lifecycle_job_name;
+        ctx.code = evt.cancelled() ? Slic3r::LifecycleEvtCode::Warn : (has_error ? Slic3r::LifecycleEvtCode::Error : Slic3r::LifecycleEvtCode::Ok);
+        ctx.msg  = evt.cancelled() ? "cancelled" : (has_error ? lifecycle_error_msg : std::string());
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::SlicingJobComplete, ctx);
+    }
+
     //BBS: set the current plater's slice result to valid
     if (!this->background_process.empty())
         this->background_process.get_current_plate()->update_slice_result_valid_state(evt.success());
@@ -13068,6 +13102,11 @@ int Plater::new_project(bool skip_confirm, bool silent, const wxString& project_
     //get_partplate_list().reinit();
     //get_partplate_list().update_slice_context_to_current_plate(p->background_process);
     //p->preview->update_gcode_result(p->partplate_list.get_current_slice_result());
+    if (!silent) {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::NewProject, ctx);
+    }
     reset(transfer_preset_changes);
     reset_project_dirty_after_save();
     reset_project_dirty_initial_presets();
@@ -13199,6 +13238,13 @@ void Plater::load_project(wxString const& filename2,
         p->set_project_name(_L("Untitled"));
         }
 
+        {
+            Slic3r::LifecycleEventContext ctx;
+            ctx.name = into_u8(load_restore ? originfile : filename);
+            ctx.code = Slic3r::LifecycleEvtCode::Ok;
+            Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ProjectOpened, ctx);
+        }
+
     } else {
         if (using_exported_file()) {
             BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << __LINE__ << " using ecported set project filename: " << filename;
@@ -13261,11 +13307,23 @@ int Plater::save_project(bool saveAs)
     if (full_pathnames) {
         save_strategy = save_strategy | SaveStrategy::FullPathSources;
     }
+    {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.name = into_u8(filename);
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ProjectBeforeSave, ctx);
+    }
     if (export_3mf(into_path(filename), save_strategy) < 0) {
         MessageDialog(this, _L("Failed to save the project.\nPlease check whether the folder exists online or if other programs have the project file open."),
             _L("Save project"), wxOK | wxICON_WARNING).ShowModal();
         return wxID_CANCEL;
     }
+    {
+        Slic3r::LifecycleEventContext ctx;
+        ctx.name = into_u8(filename);
+        ctx.code = Slic3r::LifecycleEvtCode::Ok;
+        Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::ProjectAfterSave, ctx);
+    }
 
     Slic3r::remove_backup(model(), false);
 

src/slic3r/GUI/Tab.cpp

@@ -36,6 +36,7 @@
 #include "slic3r/Utils/NetworkAgentFactory.hpp"
 #include "slic3r/Utils/PresetUpdater.hpp"
 #include "slic3r/plugin/PluginConfig.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 #include "Plater.hpp"
 #include "MainFrame.hpp"
 #include "format.hpp"
@@ -6900,6 +6901,20 @@ bool Tab::select_preset(
         }
         load_current_preset();
 
+        {
+            Slic3r::LifecycleEventContext ctx;
+            ctx.name = preset_name;
+            ctx.code = Slic3r::LifecycleEvtCode::Ok;
+            switch (m_type) {
+            case Preset::TYPE_PRINT:        ctx.msg = "print"; break;
+            case Preset::TYPE_SLA_PRINT:    ctx.msg = "sla_print"; break;
+            case Preset::TYPE_FILAMENT:     ctx.msg = "filament"; break;
+            case Preset::TYPE_SLA_MATERIAL: ctx.msg = "sla_material"; break;
+            case Preset::TYPE_PRINTER:      ctx.msg = "printer"; break;
+            default: break;
+            }
+            Slic3r::fire_lifecycle_event(Slic3r::LifecycleEvent::PresetSelected, ctx);
+        }
 
         if (delete_third_printer) {
             wxGetApp().CallAfter([filament_presets, process_presets]() {

src/slic3r/Utils/PrintHost.cpp

@@ -23,6 +23,7 @@
 #include "CrealityPrint.hpp"
 #include "../GUI/PrintHostDialogs.hpp"
 #include "../GUI/MainFrame.hpp"
+#include "slic3r/plugin/PluginManager.hpp"
 #include "Obico.hpp"
 #include "Flashforge.hpp"
 #include "SimplyPrint.hpp"
@@ -358,12 +359,29 @@ void PrintHostJobQueue::priv::perform_job(PrintHostJob the_job)
 {
     emit_progress(0);   // Indicate the upload is starting
 
+    // Captured before upload_data is moved into upload() below.
+    const std::string upload_filename = the_job.upload_data.source_path.filename().string();
+
+    {
+        LifecycleEventContext ctx;
+        ctx.name = upload_filename;
+        ctx.code = LifecycleEvtCode::Ok;
+        fire_lifecycle_event(LifecycleEvent::UploadStarted, ctx);
+    }
+
     bool success = the_job.printhost->upload(std::move(the_job.upload_data),
         [this](Http::Progress progress, bool &cancel)   { this->progress_fn(std::move(progress), cancel); },
         [this](wxString error)                          { this->error_fn(std::move(error)); },
         [this](wxString tag, wxString host)             { this->info_fn(std::move(tag), std::move(host)); }
     );
 
+    {
+        LifecycleEventContext ctx;
+        ctx.name  = upload_filename;
+        ctx.code  = success ? LifecycleEvtCode::Ok : LifecycleEvtCode::Error;
+        fire_lifecycle_event(LifecycleEvent::UploadFinished, ctx);
+    }
+
     if (success) {
         emit_progress(100);
         if (the_job.switch_to_device_tab) {

src/slic3r/plugin/PluginHooks.cpp

@@ -7,6 +7,7 @@
 
 #include "libslic3r/Config.hpp"
 #include "libslic3r/Exception.hpp"
+#include "libslic3r/LifecycleEvents.hpp"
 #include "libslic3r/Print.hpp"
 #include "libslic3r_version.h"
 
@@ -46,6 +47,16 @@ void install_capability_resolver()
     });
 }
 
+// Global libslic3r-side seam (Slic3r::fire_lifecycle_event, in libslic3r/LifecycleEvents.hpp):
+// broadcasts to every loaded, enabled capability regardless of type, unlike the SlicingPipeline
+// hook below which only targets picker-selected SlicingPipeline capabilities.
+void install_lifecycle_event_hook()
+{
+    set_lifecycle_hook_fn([](LifecycleEvent event, const LifecycleEventContext& ctx) {
+        PluginManager::instance().dispatch_lifecycle_event(event, ctx);
+    });
+}
+
 // Print::process() fires this hook at each pipeline seam on the slicing worker
 // thread; here we run the picker-selected SlicingPipeline capabilities. Per
 // capability we acquire the GIL, honor cancellation, and convert a plugin
@@ -122,12 +133,14 @@ void install()
 {
     install_capability_resolver();
     install_slicing_pipeline_hook();
+    install_lifecycle_event_hook();
 }
 
 void uninstall()
 {
     ConfigBase::set_resolve_capability_fn(nullptr);
     Print::set_slicing_pipeline_hook_fn(nullptr);
+    set_lifecycle_hook_fn(nullptr);
 }
 
 } // namespace Slic3r::plugin_hooks

src/slic3r/plugin/PluginManager.cpp

@@ -1,5 +1,6 @@
 #include "PluginManager.hpp"
 
+#include <exception>
 #include <libslic3r/Utils.hpp>
 #include <memory>
 #include <pybind11/embed.h>
@@ -1987,4 +1988,24 @@ ExecutionResult PluginManager::run_script_capability(const std::string& plugin_k
     return result;
 }
 
+void PluginManager::dispatch_lifecycle_event(LifecycleEvent evt, const LifecycleEventContext& ctx) {
+    for (const auto& cap : get_plugin_capabilities()) {
+        if (!cap || !cap->is_enabled()) continue;
+        try {
+            cap->on_lifecycle_event(evt, ctx);
+        } catch (const std::exception& ex) {
+            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << ": plugin '" << cap->audit_plugin_key() << "/" << cap->name()
+                                       << "' on_lifecycle_event(" << lifecycle_event_to_string(evt) << ") threw: " << ex.what()
+                                       << " [ctx name='" << ctx.name << "', code=" << lifecycle_evt_code_to_string(ctx.code)
+                                       << ", msg='" << ctx.msg << "']";
+        } catch (...) {
+            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << ": plugin '" << cap->audit_plugin_key() << "/" << cap->name()
+                                       << "' on_lifecycle_event(" << lifecycle_event_to_string(evt)
+                                       << ") threw a non-standard exception"
+                                       << " [ctx name='" << ctx.name << "', code=" << lifecycle_evt_code_to_string(ctx.code)
+                                       << ", msg='" << ctx.msg << "']";
+        }
+    }
+}
+
 } // namespace Slic3r

src/slic3r/plugin/PluginManager.hpp

@@ -8,6 +8,7 @@
 #include <condition_variable>
 #include <functional>
 #include <libslic3r/Config.hpp>
+#include <libslic3r/LifecycleEvents.hpp>
 #include <map>
 #include <memory>
 #include <mutex>
@@ -20,7 +21,6 @@
 #include <pybind11/embed.h>
 
 #include "CloudPluginService.hpp"
-#include "PluginFsUtils.hpp"
 #include "PluginDescriptor.hpp"
 #include "PluginLoader.hpp"
 #include "PluginConfig.hpp"
@@ -204,6 +204,8 @@ public:
 
     ExecutionResult run_script_capability(const std::string& plugin_key, const std::string& capability_name, std::string& error);
 
+    void dispatch_lifecycle_event(LifecycleEvent evt, const LifecycleEventContext& ctx);
+
 private:
     PluginManager()                                = default;
     PluginManager(const PluginManager&)            = delete;

src/slic3r/plugin/PyPluginTrampoline.hpp

@@ -129,6 +129,12 @@ public:
     {
         ORCA_PY_OVERRIDE_AUDITED(::Slic3r::PluginAuditManager::AuditMode::Loading, [] {}, PYBIND11_OVERRIDE, void, Base, on_cancelled);
     }
+
+    void on_lifecycle_event(LifecycleEvent event, const LifecycleEventContext& ctx) override
+    {
+        ORCA_PY_OVERRIDE_AUDITED(
+            ::Slic3r::PluginAuditManager::AuditMode::Loading, [] {}, PYBIND11_OVERRIDE, void, Base, on_lifecycle_event, event, ctx);
+    }
 };
 
 class PyPluginInterfaceTrampoline : public PyPluginCommonTrampoline<PluginCapabilityInterface>

src/slic3r/plugin/PythonPluginBridge.cpp

@@ -338,6 +338,44 @@ void bind_python_api(pybind11::module_& m)
         .value("FatalError", PluginResult::FatalError)
         .export_values();
 
+    py::enum_<LifecycleEvent>(m, "LifecycleEvent", "Application lifecycle moment passed to on_lifecycle_event")
+        .value("NewProject", LifecycleEvent::NewProject)
+        .value("ProjectOpened", LifecycleEvent::ProjectOpened)
+        .value("ProjectBeforeSave", LifecycleEvent::ProjectBeforeSave)
+        .value("ProjectAfterSave", LifecycleEvent::ProjectAfterSave)
+        .value("ProjectClosed", LifecycleEvent::ProjectClosed)
+        .value("SliceStarted", LifecycleEvent::SliceStarted)
+        .value("SliceGeometryFinished", LifecycleEvent::SliceGeometryFinished)
+        .value("GCodeExportStarted", LifecycleEvent::GCodeExportStarted)
+        .value("GCodeExportFinished", LifecycleEvent::GCodeExportFinished)
+        .value("SlicingJobComplete", LifecycleEvent::SlicingJobComplete)
+        .value("ObjectAdded", LifecycleEvent::ObjectAdded)
+        .value("ObjectDeleted", LifecycleEvent::ObjectDeleted)
+        .value("ObjectTransformed", LifecycleEvent::ObjectTransformed)
+        .value("PresetSelected", LifecycleEvent::PresetSelected)
+        .value("PresetSaved", LifecycleEvent::PresetSaved)
+        .value("PrintStateChanged", LifecycleEvent::PrintStateChanged)
+        .value("DeviceOnlineChanged", LifecycleEvent::DeviceOnlineChanged)
+        .value("DeviceDiscovered", LifecycleEvent::DeviceDiscovered)
+        .value("DeviceSelected", LifecycleEvent::DeviceSelected)
+        .value("DeviceConnected", LifecycleEvent::DeviceConnected)
+        .value("DeviceDisconnected", LifecycleEvent::DeviceDisconnected)
+        .value("UploadStarted", LifecycleEvent::UploadStarted)
+        .value("UploadFinished", LifecycleEvent::UploadFinished)
+        .export_values();
+
+    py::enum_<LifecycleEvtCode>(m, "LifecycleEvtCode", "Outcome code accompanying a LifecycleEventContext")
+        .value("Ok", LifecycleEvtCode::Ok)
+        .value("Error", LifecycleEvtCode::Error)
+        .value("Warn", LifecycleEvtCode::Warn)
+        .export_values();
+
+    py::class_<LifecycleEventContext>(m, "LifecycleEventContext", "Payload accompanying a LifecycleEvent")
+        .def(py::init<>())
+        .def_readonly("name", &LifecycleEventContext::name)
+        .def_readonly("code", &LifecycleEventContext::code)
+        .def_readonly("msg", &LifecycleEventContext::msg);
+
     py::class_<PluginContext>(m, "PluginContext", "Context shared with plugin entry points")
         .def(py::init<>())
         .def_readwrite("orca_version", &PluginContext::orca_version);
@@ -362,6 +400,9 @@ void bind_python_api(pybind11::module_& m)
         .def("get_type", &PluginCapabilityInterface::get_type)
         .def("on_load", &PluginCapabilityInterface::on_load)
         .def("on_unload", &PluginCapabilityInterface::on_unload)
+        .def("on_lifecycle_event", &PluginCapabilityInterface::on_lifecycle_event,
+             "Override to react to an application lifecycle moment (LifecycleEvent) and its\n"
+             "LifecycleEventContext payload. Available on every capability type.")
         .def("has_config_ui", &PluginCapabilityInterface::has_config_ui,
              "Override to return True to replace the host's default JSON editor with your own HTML\n"
              "UI, returned by get_config_ui(). Every capability is configurable and appears in the\n"

src/slic3r/plugin/PythonPluginInterface.hpp

@@ -10,6 +10,8 @@
 #include <nlohmann/json.hpp>
 #include <pybind11/embed.h>
 
+#include <libslic3r/LifecycleEvents.hpp>
+
 namespace Slic3r {
 
 enum class PluginCapabilityType { PrinterConnection = 0, Automation, Analysis, Importer, Exporter, Visualization, Script, SlicingPipeline, Unknown };
@@ -167,6 +169,8 @@ public:
     virtual void on_unload() {}
     virtual void on_cancelled() {}
 
+    virtual void on_lifecycle_event(LifecycleEvent event, const LifecycleEventContext& ctx) { (void) event; (void) ctx; }
+
     // ── C++-only host state, never exposed to Python. Set by the loader at materialization. ──
     //
     // The capability owns its own identity and enable flag: they are read once under the GIL, live