Qt: Unify worker threads

src/platform/qt/GBAApp.cpp

@@ -67,10 +67,7 @@ GBAApp::GBAApp(int& argc, char* argv[], ConfigController* config)
 }
 
 GBAApp::~GBAApp() {
-#ifdef USE_SQLITE3
-	m_parseThread.quit();
-	m_parseThread.wait();
-#endif
+	m_workerThreads.waitForDone();
 }
 
 bool GBAApp::event(QEvent* event) {
@@ -180,14 +177,8 @@ bool GBAApp::reloadGameDB() {
 		NoIntroDBDestroy(m_db);
 	}
 	if (db) {
-		if (m_parseThread.isRunning()) {
-			m_parseThread.quit();
-			m_parseThread.wait();
-		}
 		GameDBParser* parser = new GameDBParser(db);
-		m_parseThread.start();
-		parser->moveToThread(&m_parseThread);
-		QMetaObject::invokeMethod(parser, "parseNoIntroDB");
+		submitWorkerJob(std::bind(&GameDBParser::parseNoIntroDB, parser));
 		m_db = db;
 		return true;
 	}
@@ -199,6 +190,77 @@ bool GBAApp::reloadGameDB() {
 }
 #endif
 
+qint64 GBAApp::submitWorkerJob(std::function<void ()> job, std::function<void ()> callback) {
+	return submitWorkerJob(job, nullptr, callback);
+}
+
+qint64 GBAApp::submitWorkerJob(std::function<void ()> job, QObject* context, std::function<void ()> callback) {
+	qint64 jobId = m_nextJob;
+	++m_nextJob;
+	WorkerJob* jobRunnable = new WorkerJob(jobId, job, this);
+	m_workerJobs.insert(jobId, jobRunnable);
+	if (callback) {
+		waitOnJob(jobId, context, callback);
+	}
+	m_workerThreads.start(jobRunnable);
+	return jobId;
+}
+
+bool GBAApp::removeWorkerJob(qint64 jobId) {
+	for (auto& job : m_workerJobCallbacks.values(jobId)) {
+		disconnect(job);
+	}
+	m_workerJobCallbacks.remove(jobId);
+	if (!m_workerJobs.contains(jobId)) {
+		return true;
+	}
+	bool success = false;
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 9, 0))
+	success = m_workerThreads.tryTake(m_workerJobs[jobId]);
+#endif
+	if (success) {
+		m_workerJobs.remove(jobId);
+	}
+	return success;
+}
+
+
+bool GBAApp::waitOnJob(qint64 jobId, QObject* context, std::function<void ()> callback) {
+	if (!m_workerJobs.contains(jobId)) {
+		return false;
+	}
+	if (!context) {
+		context = this;
+	}
+	QMetaObject::Connection connection = connect(this, &GBAApp::jobFinished, context, [jobId, callback](qint64 testedJobId) {
+		if (jobId != testedJobId) {
+			return;
+		}
+		callback();
+	});
+	m_workerJobCallbacks.insert(m_nextJob, connection);
+	return true;
+}
+
+void GBAApp::finishJob(qint64 jobId) {
+	m_workerJobs.remove(jobId);
+	emit jobFinished(jobId);
+	m_workerJobCallbacks.remove(jobId);
+}
+
+GBAApp::WorkerJob::WorkerJob(qint64 id, std::function<void ()> job, GBAApp* owner)
+	: m_id(id)
+	, m_job(job)
+	, m_owner(owner)
+{
+	setAutoDelete(true);
+}
+
+void GBAApp::WorkerJob::run() {
+	m_job();
+	QMetaObject::invokeMethod(m_owner, "finishJob", Q_ARG(qint64, m_id));
+}
+
 #ifdef USE_SQLITE3
 GameDBParser::GameDBParser(NoIntroDB* db, QObject* parent)
 	: QObject(parent)

src/platform/qt/GBAApp.h

@@ -8,9 +8,14 @@
 #include <QApplication>
 #include <QFileDialog>
 #include <QList>
+#include <QMap>
+#include <QMultiMap>
 #include <QObject>
+#include <QRunnable>
 #include <QString>
-#include <QThread>
+#include <QThreadPool>
+
+#include <functional>
 
 #include "CoreManager.h"
 #include "MultiplayerController.h"
@@ -61,10 +66,34 @@ public:
 	const NoIntroDB* gameDB() const { return m_db; }
 	bool reloadGameDB();
 
+	qint64 submitWorkerJob(std::function<void ()> job, std::function<void ()> callback = {});
+	qint64 submitWorkerJob(std::function<void ()> job, QObject* context, std::function<void ()> callback);
+	bool removeWorkerJob(qint64 jobId);
+	bool waitOnJob(qint64 jobId, QObject* context, std::function<void ()> callback);
+
+signals:
+	void jobFinished(qint64 jobId);
+
 protected:
 	bool event(QEvent*);
 
+private slots:
+	void finishJob(qint64 jobId);
+
 private:
+	class WorkerJob : public QRunnable {
+	public:
+		WorkerJob(qint64 id, std::function<void ()> job, GBAApp* owner);
+
+	public:
+		void run() override;
+
+	private:
+		qint64 m_id;
+		std::function<void ()> m_job;
+		GBAApp* m_owner;
+	};
+
 	Window* newWindowInternal();
 
 	void pauseAll(QList<Window*>* paused);
@@ -75,10 +104,12 @@ private:
 	MultiplayerController m_multiplayer;
 	CoreManager m_manager;
 
+	QMap<qint64, WorkerJob*> m_workerJobs;
+	QMultiMap<qint64, QMetaObject::Connection> m_workerJobCallbacks;
+	QThreadPool m_workerThreads;
+	qint64 m_nextJob = 1;
+
 	NoIntroDB* m_db = nullptr;
-#ifdef USE_SQLITE3
-	QThread m_parseThread;
-#endif
 };
 
 }

src/platform/qt/library/LibraryController.cpp

@@ -29,16 +29,6 @@ void AbstractGameList::removeEntries(QList<LibraryEntryRef> items) {
 	}
 }
 
-LibraryLoaderThread::LibraryLoaderThread(QObject* parent)
-	: QThread(parent)
-{
-}
-
-void LibraryLoaderThread::run() {
-	mLibraryLoadDirectory(m_library, m_directory.toUtf8().constData());
-	m_directory = QString();
-}
-
 LibraryController::LibraryController(QWidget* parent, const QString& path, ConfigController* config)
 	: QStackedWidget(parent)
 	, m_config(config)
@@ -47,13 +37,13 @@ LibraryController::LibraryController(QWidget* parent, const QString& path, Confi
 
 	if (!path.isNull()) {
 		// This can return NULL if the library is already open
-		m_library = mLibraryLoad(path.toUtf8().constData());
+		m_library = std::shared_ptr<mLibrary>(mLibraryLoad(path.toUtf8().constData()), mLibraryDestroy);
 	}
 	if (!m_library) {
-		m_library = mLibraryCreateEmpty();
+		m_library = std::shared_ptr<mLibrary>(mLibraryCreateEmpty(), mLibraryDestroy);
 	}
 
-	mLibraryAttachGameDB(m_library, GBAApp::app()->gameDB());
+	mLibraryAttachGameDB(m_library.get(), GBAApp::app()->gameDB());
 
 	m_libraryTree = new LibraryTree(this);
 	addWidget(m_libraryTree->widget());
@@ -61,25 +51,12 @@ LibraryController::LibraryController(QWidget* parent, const QString& path, Confi
 	m_libraryGrid = new LibraryGrid(this);
 	addWidget(m_libraryGrid->widget());
 
-	connect(&m_loaderThread, &QThread::finished, this, &LibraryController::refresh, Qt::QueuedConnection);
-
 	setViewStyle(LibraryStyle::STYLE_LIST);
 	refresh();
 }
 
 LibraryController::~LibraryController() {
 	mLibraryListingDeinit(&m_listing);
-
-	if (m_loaderThread.isRunning()) {
-		m_loaderThread.wait();
-	}
-	if (!m_loaderThread.isRunning() && m_loaderThread.m_library) {
-		m_library = m_loaderThread.m_library;
-		m_loaderThread.m_library = nullptr;
-	}
-	if (m_library) {
-		mLibraryDestroy(m_library);
-	}
 }
 
 void LibraryController::setViewStyle(LibraryStyle newStyle) {
@@ -117,7 +94,7 @@ LibraryEntryRef LibraryController::selectedEntry() {
 VFile* LibraryController::selectedVFile() {
 	LibraryEntryRef entry = selectedEntry();
 	if (entry) {
-		return mLibraryOpenVFile(m_library, entry->entry);
+		return mLibraryOpenVFile(m_library.get(), entry->entry);
 	} else {
 		return nullptr;
 	}
@@ -129,35 +106,26 @@ QPair<QString, QString> LibraryController::selectedPath() {
 }
 
 void LibraryController::addDirectory(const QString& dir) {
-	m_loaderThread.m_directory = dir;
-	m_loaderThread.m_library = m_library;
-	// The m_loaderThread temporarily owns the library
-	m_library = nullptr;
-	m_loaderThread.start();
+	// The worker thread temporarily owns the library
+	std::shared_ptr<mLibrary> library = m_library;
+	m_libraryJob = GBAApp::app()->submitWorkerJob(std::bind(&LibraryController::loadDirectory, this, dir), this, [this, library]() {
+		m_libraryJob = -1;
+		refresh();
+	});
 }
 
 void LibraryController::clear() {
-	if (!m_library) {
-		if (!m_loaderThread.isRunning() && m_loaderThread.m_library) {
-			m_library = m_loaderThread.m_library;
-			m_loaderThread.m_library = nullptr;
-		} else {
-			return;
-		}
+	if (m_libraryJob > 0) {
+		return;
 	}
 
-	mLibraryClear(m_library);
+	mLibraryClear(m_library.get());
 	refresh();
 }
 
 void LibraryController::refresh() {
-	if (!m_library) {
-		if (!m_loaderThread.isRunning() && m_loaderThread.m_library) {
-			m_library = m_loaderThread.m_library;
-			m_loaderThread.m_library = nullptr;
-		} else {
-			return;
-		}
+	if (m_libraryJob > 0) {
+		return;
 	}
 
 	setDisabled(true);
@@ -166,7 +134,7 @@ void LibraryController::refresh() {
 	QList<LibraryEntryRef> newEntries;
 
 	mLibraryListingClear(&m_listing);
-	mLibraryGetEntries(m_library, &m_listing, 0, 0, nullptr);
+	mLibraryGetEntries(m_library.get(), &m_listing, 0, 0, nullptr);
 	for (size_t i = 0; i < mLibraryListingSize(&m_listing); i++) {
 		mLibraryEntry* entry = mLibraryListingGetPointer(&m_listing, i);
 		QString fullpath = QString("%1/%2").arg(entry->base, entry->filename);
@@ -210,4 +178,10 @@ void LibraryController::selectLastBootedGame() {
 	}
 }
 
+void LibraryController::loadDirectory(const QString& dir) {
+	// This class can get delted during this function (sigh) so we need to hold onto this
+	std::shared_ptr<mLibrary> library = m_library;
+	mLibraryLoadDirectory(library.get(), dir.toUtf8().constData());
+}
+
 }

src/platform/qt/library/LibraryController.h

@@ -9,7 +9,6 @@
 
 #include <QList>
 #include <QMap>
-#include <QThread>
 #include <QStackedWidget>
 
 #include <mgba/core/library.h>
@@ -66,19 +65,6 @@ public:
 	virtual QWidget* widget() = 0;
 };
 
-class LibraryLoaderThread final : public QThread {
-Q_OBJECT
-
-public:
-	LibraryLoaderThread(QObject* parent = nullptr);
-
-	mLibrary* m_library = nullptr;
-	QString m_directory;
-
-protected:
-	virtual void run() override;
-};
-
 class LibraryController final : public QStackedWidget {
 Q_OBJECT
 
@@ -110,9 +96,11 @@ private slots:
 	void refresh();
 
 private:
+	void loadDirectory(const QString&); // Called on separate thread
+
 	ConfigController* m_config = nullptr;
-	LibraryLoaderThread m_loaderThread;
-	mLibrary* m_library = nullptr;
+	std::shared_ptr<mLibrary> m_library;
+	qint64 m_libraryJob = -1;
 	mLibraryListing m_listing;
 	QMap<QString, LibraryEntryRef> m_entries;