feat: faster startup by lazy-loading main window panels on idle or first use (#15811)

tests/slic3rutils/test_prebuild_queue.cpp

@@ -0,0 +1,183 @@
+#include <catch2/catch_all.hpp>
+
+#include <string>
+#include <vector>
+
+#include "slic3r/GUI/PrebuildQueue.hpp"
+
+using Slic3r::GUI::LazyBase;
+using Slic3r::GUI::PrebuildQueue;
+
+namespace {
+
+// A task with `left` units, each taking `unit_ms` of the shared fake clock and logging its id.
+struct Counter : LazyBase
+{
+    std::string      id;
+    int              left;
+    int              order;
+    long long        unit_ms{ 1 };
+    inline static std::vector<int> log;
+    inline static long long        now = 0;
+
+    Counter(int id, int left, int order, long long unit_ms = 1) : id(std::to_string(id)), left(left), order(order), unit_ms(unit_ms) {}
+
+    const std::string& name() const override { return id; }
+    bool               built() const override { return left == 0; }
+    bool               build_step() override
+    {
+        now += unit_ms;
+        log.push_back(std::stoi(id));
+        return --left > 0;
+    }
+    int prebuild_order() const override { return order; }
+};
+
+// Resets the shared log and clock at the start of a case.
+struct Reset
+{
+    Reset() { Counter::log.clear(); Counter::now = 0; }
+};
+
+const auto fake_clock    = [] { return Counter::now; };
+const auto no_input = [] { return false; };
+
+// Runs slices with an unlimited budget until nothing is pending; one task per slice.
+void drain(PrebuildQueue& q)
+{
+    while (q.pending())
+        q.run_slice(1000000, fake_clock, no_input);
+}
+
+} // namespace
+
+TEST_CASE("Tasks run lowest order first, equal order in the order added", "[PrebuildQueue]")
+{
+    Reset   reset;
+    Counter a{ 1, 1, 10 }, b{ 2, 1, 10 }, c{ 3, 1, 50 }, d{ 4, 1, 100 };
+    PrebuildQueue q;
+    q.add(c);
+    q.add(a);
+    q.add(b);
+    q.add(d);
+    REQUIRE(q.names() == "1, 2, 3, 4");
+    drain(q);
+    REQUIRE(Counter::log == std::vector<int>{1, 2, 3, 4});
+}
+
+TEST_CASE("A task with nothing pending is skipped, not removed", "[PrebuildQueue]")
+{
+    Reset   reset;
+    Counter a{ 1, 0, 0 }, b{ 2, 2, 1 };
+    PrebuildQueue q;
+    q.add(a);
+    q.add(b);
+    REQUIRE(q.pending());
+    auto slice = q.run_slice(1, fake_clock, no_input); // one unit of b
+    REQUIRE(slice.units == 1);
+    REQUIRE(Counter::log == std::vector<int>{2});
+
+    a.left = 1; // a's work returned; it comes first again
+    q.run_slice(1, fake_clock, no_input);
+    REQUIRE(Counter::log == std::vector<int>{2, 1});
+}
+
+TEST_CASE("A slice with nothing pending runs no unit", "[PrebuildQueue]")
+{
+    Reset         reset;
+    PrebuildQueue q;
+    REQUIRE_FALSE(q.pending());
+    auto slice = q.run_slice(40, fake_clock, no_input);
+    REQUIRE(slice.units == 0);
+    REQUIRE_FALSE(slice.completed);
+    REQUIRE_FALSE(slice.remaining);
+}
+
+TEST_CASE("A slice stops once its budget is spent, after the unit that crossed it", "[PrebuildQueue]")
+{
+    Reset   reset;
+    Counter a{ 1, 10, 0, 15 };
+    PrebuildQueue q;
+    q.add(a);
+    auto slice = q.run_slice(40, fake_clock, no_input);
+    REQUIRE(slice.units == 3); // units end at 15, 30 and 45 ms; the one crossing 40 is the last
+    REQUIRE(slice.ms == 45);
+    REQUIRE_FALSE(slice.completed);
+    REQUIRE(slice.remaining);
+    REQUIRE(a.left == 7);
+}
+
+TEST_CASE("A slice stops after the unit during which input arrived", "[PrebuildQueue]")
+{
+    Reset   reset;
+    Counter a{ 1, 10, 0 };
+    bool    input = false;
+    PrebuildQueue q;
+    q.add(a);
+    auto slice = q.run_slice(40, fake_clock, [&] { input = a.left == 8; return input; });
+    REQUIRE(slice.units == 2);
+    REQUIRE_FALSE(slice.completed);
+    REQUIRE(slice.remaining);
+}
+
+TEST_CASE("A slice reports completion, whether work remains, and each unit's time", "[PrebuildQueue]")
+{
+    Reset                  reset;
+    Counter                a{ 1, 2, 0, 5 }, b{ 2, 1, 1 };
+    std::vector<long long> unit_ms;
+    PrebuildQueue          q;
+    q.add(a);
+    q.add(b);
+    auto slice = q.run_slice(40, fake_clock, no_input, [&](const std::string& name, long long ms) {
+        REQUIRE(name == "1");
+        unit_ms.push_back(ms);
+    });
+    REQUIRE(slice.units == 2);
+    REQUIRE(slice.completed);
+    REQUIRE(slice.name == "1");
+    REQUIRE(slice.remaining); // b
+    REQUIRE(unit_ms == std::vector<long long>{5, 5});
+    slice = q.run_slice(40, fake_clock, no_input);
+    REQUIRE(slice.completed);
+    REQUIRE_FALSE(slice.remaining);
+    REQUIRE_FALSE(q.pending());
+}
+
+TEST_CASE("A unit may add a task to the queue it runs from", "[PrebuildQueue]")
+{
+    Reset         reset;
+    PrebuildQueue q;
+    Counter       later{ 2, 1, 5 };
+    struct Adder : LazyBase
+    {
+        PrebuildQueue& q;
+        Counter&       later;
+        std::string    id{ "1" };
+        bool           done{ false };
+        Adder(PrebuildQueue& q, Counter& later) : q(q), later(later) {}
+        const std::string& name() const override { return id; }
+        bool               built() const override { return done; }
+        bool               build_step() override
+        {
+            Counter::log.push_back(1);
+            done = true;
+            q.add(later);
+            return false;
+        }
+        int prebuild_order() const override { return 0; }
+    } first{ q, later };
+    q.add(first);
+    drain(q);
+    REQUIRE(Counter::log == std::vector<int>{1, 2});
+}
+
+TEST_CASE("clear drops every task", "[PrebuildQueue]")
+{
+    Reset   reset;
+    Counter a{ 1, 1, 0 };
+    PrebuildQueue q;
+    q.add(a);
+    q.clear();
+    REQUIRE_FALSE(q.pending());
+    REQUIRE(q.run_slice(40, fake_clock, no_input).units == 0);
+}