qt: fix game list shutdown crash

src/yuzu/game_list.cpp

@@ -380,7 +380,6 @@ void GameList::UnloadController() {
 
 GameList::~GameList() {
     UnloadController();
-    emit ShouldCancelWorker();
 }
 
 void GameList::SetFilterFocus() {
@@ -397,6 +396,10 @@ void GameList::ClearFilter() {
     search_field->clear();
 }
 
+void GameList::WorkerEvent() {
+    current_worker->ProcessEvents(this);
+}
+
 void GameList::AddDirEntry(GameListDir* entry_items) {
     item_model->invisibleRootItem()->appendRow(entry_items);
     tree_view->setExpanded(
@@ -826,28 +829,21 @@ void GameList::PopulateAsync(QVector<UISettings::GameDir>& game_dirs) {
     tree_view->setColumnHidden(COLUMN_SIZE, !UISettings::values.show_size);
     tree_view->setColumnHidden(COLUMN_PLAY_TIME, !UISettings::values.show_play_time);
 
-    // Before deleting rows, cancel the worker so that it is not using them
-    emit ShouldCancelWorker();
+    // Cancel any existing worker.
+    current_worker.reset();
 
     // Delete any rows that might already exist if we're repopulating
     item_model->removeRows(0, item_model->rowCount());
     search_field->clear();
 
-    GameListWorker* worker =
-        new GameListWorker(vfs, provider, game_dirs, compatibility_list, play_time_manager, system);
+    current_worker = std::make_unique<GameListWorker>(vfs, provider, game_dirs, compatibility_list,
+                                                      play_time_manager, system);
 
-    connect(worker, &GameListWorker::EntryReady, this, &GameList::AddEntry, Qt::QueuedConnection);
-    connect(worker, &GameListWorker::DirEntryReady, this, &GameList::AddDirEntry,
-            Qt::QueuedConnection);
-    connect(worker, &GameListWorker::Finished, this, &GameList::DonePopulating,
+    // Get events from the worker as data becomes available
+    connect(current_worker.get(), &GameListWorker::DataAvailable, this, &GameList::WorkerEvent,
             Qt::QueuedConnection);
-    // Use DirectConnection here because worker->Cancel() is thread-safe and we want it to
-    // cancel without delay.
-    connect(this, &GameList::ShouldCancelWorker, worker, &GameListWorker::Cancel,
-            Qt::DirectConnection);
 
-    QThreadPool::globalInstance()->start(worker);
-    current_worker = std::move(worker);
+    QThreadPool::globalInstance()->start(current_worker.get());
 }
 
 void GameList::SaveInterfaceLayout() {

src/yuzu/game_list.h

@@ -109,7 +109,6 @@ signals:
     void BootGame(const QString& game_path, u64 program_id, std::size_t program_index,
                   StartGameType type, AmLaunchType launch_type);
     void GameChosen(const QString& game_path, const u64 title_id = 0);
-    void ShouldCancelWorker();
     void OpenFolderRequested(u64 program_id, GameListOpenTarget target,
                              const std::string& game_path);
     void OpenTransferableShaderCacheRequested(u64 program_id);
@@ -138,11 +137,16 @@ private slots:
     void OnUpdateThemedIcons();
 
 private:
+    friend class GameListWorker;
+    void WorkerEvent();
+
     void AddDirEntry(GameListDir* entry_items);
     void AddEntry(const QList<QStandardItem*>& entry_items, GameListDir* parent);
-    void ValidateEntry(const QModelIndex& item);
     void DonePopulating(const QStringList& watch_list);
 
+private:
+    void ValidateEntry(const QModelIndex& item);
+
     void RefreshGameDirectory();
 
     void ToggleFavorite(u64 program_id);
@@ -165,7 +169,7 @@ private:
     QVBoxLayout* layout = nullptr;
     QTreeView* tree_view = nullptr;
     QStandardItemModel* item_model = nullptr;
-    GameListWorker* current_worker = nullptr;
+    std::unique_ptr<GameListWorker> current_worker;
     QFileSystemWatcher* watcher = nullptr;
     ControllerNavigation* controller_navigation = nullptr;
     CompatibilityList compatibility_list;

src/yuzu/game_list_worker.cpp

@@ -233,10 +233,53 @@ GameListWorker::GameListWorker(FileSys::VirtualFilesystem vfs_,
                                const PlayTime::PlayTimeManager& play_time_manager_,
                                Core::System& system_)
     : vfs{std::move(vfs_)}, provider{provider_}, game_dirs{game_dirs_},
-      compatibility_list{compatibility_list_},
-      play_time_manager{play_time_manager_}, system{system_} {}
+      compatibility_list{compatibility_list_}, play_time_manager{play_time_manager_}, system{
+                                                                                          system_} {
+    // We want the game list to manage our lifetime.
+    setAutoDelete(false);
+}
+
+GameListWorker::~GameListWorker() {
+    this->disconnect();
+    stop_requested.store(true);
+    processing_completed.Wait();
+}
+
+void GameListWorker::ProcessEvents(GameList* game_list) {
+    while (true) {
+        std::function<void(GameList*)> func;
+        {
+            // Lock queue to protect concurrent modification.
+            std::scoped_lock lk(lock);
+
+            // If we can't pop a function, return.
+            if (queued_events.empty()) {
+                return;
+            }
+
+            // Pop a function.
+            func = std::move(queued_events.back());
+            queued_events.pop_back();
+        }
+
+        // Run the function.
+        func(game_list);
+    }
+}
+
+template <typename F>
+void GameListWorker::RecordEvent(F&& func) {
+    {
+        // Lock queue to protect concurrent modification.
+        std::scoped_lock lk(lock);
 
-GameListWorker::~GameListWorker() = default;
+        // Add the function into the front of the queue.
+        queued_events.emplace_front(std::move(func));
+    }
+
+    // Data now available.
+    emit DataAvailable();
+}
 
 void GameListWorker::AddTitlesToGameList(GameListDir* parent_dir) {
     using namespace FileSys;
@@ -284,9 +327,9 @@ void GameListWorker::AddTitlesToGameList(GameListDir* parent_dir) {
             GetMetadataFromControlNCA(patch, *control, icon, name);
         }
 
-        emit EntryReady(MakeGameListEntry(file->GetFullPath(), name, file->GetSize(), icon, *loader,
-                                          program_id, compatibility_list, play_time_manager, patch),
-                        parent_dir);
+        auto entry = MakeGameListEntry(file->GetFullPath(), name, file->GetSize(), icon, *loader,
+                                       program_id, compatibility_list, play_time_manager, patch);
+        RecordEvent([=](GameList* game_list) { game_list->AddEntry(entry, parent_dir); });
     }
 }
 
@@ -360,11 +403,12 @@ void GameListWorker::ScanFileSystem(ScanTarget target, const std::string& dir_pa
                         const FileSys::PatchManager patch{id, system.GetFileSystemController(),
                                                           system.GetContentProvider()};
 
-                        emit EntryReady(MakeGameListEntry(physical_name, name,
-                                                          Common::FS::GetSize(physical_name), icon,
-                                                          *loader, id, compatibility_list,
-                                                          play_time_manager, patch),
-                                        parent_dir);
+                        auto entry = MakeGameListEntry(
+                            physical_name, name, Common::FS::GetSize(physical_name), icon, *loader,
+                            id, compatibility_list, play_time_manager, patch);
+
+                        RecordEvent(
+                            [=](GameList* game_list) { game_list->AddEntry(entry, parent_dir); });
                     }
                 } else {
                     std::vector<u8> icon;
@@ -376,11 +420,12 @@ void GameListWorker::ScanFileSystem(ScanTarget target, const std::string& dir_pa
                     const FileSys::PatchManager patch{program_id, system.GetFileSystemController(),
                                                       system.GetContentProvider()};
 
-                    emit EntryReady(MakeGameListEntry(physical_name, name,
-                                                      Common::FS::GetSize(physical_name), icon,
-                                                      *loader, program_id, compatibility_list,
-                                                      play_time_manager, patch),
-                                    parent_dir);
+                    auto entry = MakeGameListEntry(
+                        physical_name, name, Common::FS::GetSize(physical_name), icon, *loader,
+                        program_id, compatibility_list, play_time_manager, patch);
+
+                    RecordEvent(
+                        [=](GameList* game_list) { game_list->AddEntry(entry, parent_dir); });
                 }
             }
         } else if (is_dir) {
@@ -399,25 +444,34 @@ void GameListWorker::ScanFileSystem(ScanTarget target, const std::string& dir_pa
 }
 
 void GameListWorker::run() {
+    watch_list.clear();
     provider->ClearAllEntries();
 
+    const auto DirEntryReady = [&](GameListDir* game_list_dir) {
+        RecordEvent([=](GameList* game_list) { game_list->AddDirEntry(game_list_dir); });
+    };
+
     for (UISettings::GameDir& game_dir : game_dirs) {
+        if (stop_requested) {
+            break;
+        }
+
         if (game_dir.path == QStringLiteral("SDMC")) {
             auto* const game_list_dir = new GameListDir(game_dir, GameListItemType::SdmcDir);
-            emit DirEntryReady(game_list_dir);
+            DirEntryReady(game_list_dir);
             AddTitlesToGameList(game_list_dir);
         } else if (game_dir.path == QStringLiteral("UserNAND")) {
             auto* const game_list_dir = new GameListDir(game_dir, GameListItemType::UserNandDir);
-            emit DirEntryReady(game_list_dir);
+            DirEntryReady(game_list_dir);
             AddTitlesToGameList(game_list_dir);
         } else if (game_dir.path == QStringLiteral("SysNAND")) {
             auto* const game_list_dir = new GameListDir(game_dir, GameListItemType::SysNandDir);
-            emit DirEntryReady(game_list_dir);
+            DirEntryReady(game_list_dir);
             AddTitlesToGameList(game_list_dir);
         } else {
             watch_list.append(game_dir.path);
             auto* const game_list_dir = new GameListDir(game_dir);
-            emit DirEntryReady(game_list_dir);
+            DirEntryReady(game_list_dir);
             ScanFileSystem(ScanTarget::FillManualContentProvider, game_dir.path.toStdString(),
                            game_dir.deep_scan, game_list_dir);
             ScanFileSystem(ScanTarget::PopulateGameList, game_dir.path.toStdString(),
@@ -425,12 +479,6 @@ void GameListWorker::run() {
         }
     }
 
-    emit Finished(watch_list);
+    RecordEvent([=](GameList* game_list) { game_list->DonePopulating(watch_list); });
     processing_completed.Set();
 }
-
-void GameListWorker::Cancel() {
-    this->disconnect();
-    stop_requested.store(true);
-    processing_completed.Wait();
-}

src/yuzu/game_list_worker.h

@@ -4,6 +4,7 @@
 #pragma once
 
 #include <atomic>
+#include <deque>
 #include <memory>
 #include <string>
 
@@ -20,6 +21,7 @@ namespace Core {
 class System;
 }
 
+class GameList;
 class QStandardItem;
 
 namespace FileSys {
@@ -46,24 +48,22 @@ public:
     /// Starts the processing of directory tree information.
     void run() override;
 
-    /// Tells the worker that it should no longer continue processing. Thread-safe.
-    void Cancel();
-
-signals:
+public:
     /**
-     * The `EntryReady` signal is emitted once an entry has been prepared and is ready
-     * to be added to the game list.
-     * @param entry_items a list with `QStandardItem`s that make up the columns of the new
-     * entry.
+     * Synchronously processes any events queued by the worker.
+     *
+     * AddDirEntry is called on the game list for every discovered directory.
+     * AddEntry is called on the game list for every discovered program.
+     * DonePopulating is called on the game list when processing completes.
      */
-    void DirEntryReady(GameListDir* entry_items);
-    void EntryReady(QList<QStandardItem*> entry_items, GameListDir* parent_dir);
+    void ProcessEvents(GameList* game_list);
 
-    /**
-     * After the worker has traversed the game directory looking for entries, this signal is
-     * emitted with a list of folders that should be watched for changes as well.
-     */
-    void Finished(QStringList watch_list);
+signals:
+    void DataAvailable();
+
+private:
+    template <typename F>
+    void RecordEvent(F&& func);
 
 private:
     void AddTitlesToGameList(GameListDir* parent_dir);
@@ -84,8 +84,11 @@ private:
 
     QStringList watch_list;
 
-    Common::Event processing_completed;
+    std::mutex lock;
+    std::condition_variable cv;
+    std::deque<std::function<void(GameList*)>> queued_events;
     std::atomic_bool stop_requested = false;
+    Common::Event processing_completed;
 
     Core::System& system;
 };