DolphinQt2: Perform more of GameTracker's work on a separate thread

This reduces the time from startup to the game list window showing up.

Source/Core/DolphinQt2/GameList/GameTracker.cpp

@@ -22,22 +22,61 @@ GameTracker::GameTracker(QObject* parent) : QFileSystemWatcher(parent)
   connect(this, &QFileSystemWatcher::directoryChanged, this, &GameTracker::UpdateDirectory);
   connect(this, &QFileSystemWatcher::fileChanged, this, &GameTracker::UpdateFile);
 
+  m_load_thread.Reset([this](Command command) {
+    switch (command.type)
+    {
+    case CommandType::LoadCache:
       m_cache.Load();
+      break;
+    case CommandType::AddDirectory:
+      AddDirectoryInternal(command.path);
+      break;
+    case CommandType::RemoveDirectory:
+      RemoveDirectoryInternal(command.path);
+      break;
+    case CommandType::UpdateDirectory:
+      UpdateDirectoryInternal(command.path);
+      break;
+    case CommandType::UpdateFile:
+      UpdateFileInternal(command.path);
+      break;
+    }
+  });
 
-  m_load_thread.Reset([this](const QString& path) { LoadGame(path); });
+  m_load_thread.EmplaceItem(Command{CommandType::LoadCache, {}});
 
   // TODO: When language changes, reload m_title_database and call m_cache.UpdateAdditionalMetadata
 }
 
 void GameTracker::AddDirectory(const QString& dir)
 {
-  if (!QFileInfo(dir).exists())
+  m_load_thread.EmplaceItem(Command{CommandType::AddDirectory, dir});
-    return;
-  addPath(dir);
-  UpdateDirectory(dir);
 }
 
 void GameTracker::RemoveDirectory(const QString& dir)
+{
+  m_load_thread.EmplaceItem(Command{CommandType::RemoveDirectory, dir});
+}
+
+void GameTracker::UpdateDirectory(const QString& dir)
+{
+  m_load_thread.EmplaceItem(Command{CommandType::UpdateDirectory, dir});
+}
+
+void GameTracker::UpdateFile(const QString& dir)
+{
+  m_load_thread.EmplaceItem(Command{CommandType::UpdateFile, dir});
+}
+
+void GameTracker::AddDirectoryInternal(const QString& dir)
+{
+  if (!QFileInfo(dir).exists())
+    return;
+  addPath(dir);
+  UpdateDirectoryInternal(dir);
+}
+
+void GameTracker::RemoveDirectoryInternal(const QString& dir)
 {
   removePath(dir);
   QDirIterator it(dir, game_filters, QDir::NoFilter, QDirIterator::Subdirectories);
@@ -57,7 +96,7 @@ void GameTracker::RemoveDirectory(const QString& dir)
   }
 }
 
-void GameTracker::UpdateDirectory(const QString& dir)
+void GameTracker::UpdateDirectoryInternal(const QString& dir)
 {
   QDirIterator it(dir, game_filters, QDir::NoFilter, QDirIterator::Subdirectories);
   while (it.hasNext())
@@ -74,7 +113,7 @@ void GameTracker::UpdateDirectory(const QString& dir)
     {
       addPath(path);
       m_tracked_files[path] = QSet<QString>{dir};
-      m_load_thread.EmplaceItem(path);
+      LoadGame(path);
     }
   }
 
@@ -91,6 +130,21 @@ void GameTracker::UpdateDirectory(const QString& dir)
   }
 }
 
+void GameTracker::UpdateFileInternal(const QString& file)
+{
+  if (QFileInfo(file).exists())
+  {
+    GameRemoved(file);
+    addPath(file);
+    LoadGame(file);
+  }
+  else if (removePath(file))
+  {
+    m_tracked_files.remove(file);
+    emit GameRemoved(file);
+  }
+}
+
 QSet<QString> GameTracker::FindMissingFiles(const QString& dir)
 {
   QDirIterator it(dir, game_filters, QDir::NoFilter, QDirIterator::Subdirectories);
@@ -113,22 +167,6 @@ QSet<QString> GameTracker::FindMissingFiles(const QString& dir)
   return missing_files;
 }
 
-void GameTracker::UpdateFile(const QString& file)
-{
-  if (QFileInfo(file).exists())
-  {
-    GameRemoved(file);
-    addPath(file);
-
-    m_load_thread.EmplaceItem(file);
-  }
-  else if (removePath(file))
-  {
-    m_tracked_files.remove(file);
-    emit GameRemoved(file);
-  }
-}
-
 void GameTracker::LoadGame(const QString& path)
 {
   const std::string converted_path = path.toStdString();

Source/Core/DolphinQt2/GameList/GameTracker.h

@@ -34,14 +34,33 @@ signals:
   void GameRemoved(const QString& path);
 
 private:
-  void LoadGame(const QString& path);
   void UpdateDirectory(const QString& dir);
   void UpdateFile(const QString& path);
+  void AddDirectoryInternal(const QString& dir);
+  void RemoveDirectoryInternal(const QString& dir);
+  void UpdateDirectoryInternal(const QString& dir);
+  void UpdateFileInternal(const QString& path);
   QSet<QString> FindMissingFiles(const QString& dir);
+  void LoadGame(const QString& path);
+
+  enum class CommandType
+  {
+    LoadCache,
+    AddDirectory,
+    RemoveDirectory,
+    UpdateDirectory,
+    UpdateFile,
+  };
+
+  struct Command
+  {
+    CommandType type;
+    QString path;
+  };
 
   // game path -> directories that track it
   QMap<QString, QSet<QString>> m_tracked_files;
-  Common::WorkQueueThread<QString> m_load_thread;
+  Common::WorkQueueThread<Command> m_load_thread;
   UICommon::GameFileCache m_cache;
   Core::TitleDatabase m_title_database;
 };