Safely close database connections and delete backends

Also fix NewClosure leak caused by disconnected object signals

src/core/application.cpp

@@ -223,10 +223,12 @@ Application::~Application() {
 
   for (QThread *thread : threads_) {
     thread->wait();
+    thread->deleteLater();
   }
+
 }
 
-void Application::MoveToNewThread(QObject *object) {
+QThread *Application::MoveToNewThread(QObject *object) {
 
   QThread *thread = new QThread(this);
 
@@ -234,6 +236,9 @@ void Application::MoveToNewThread(QObject *object) {
 
   thread->start();
   threads_ << thread;
+
+  return thread;
+
 }
 
 void Application::MoveToThread(QObject *object, QThread *thread) {
@@ -241,6 +246,38 @@ void Application::MoveToThread(QObject *object, QThread *thread) {
   object->moveToThread(thread);
 }
 
+void Application::Exit() {
+
+  wait_for_exit_ << collection()
+                 << playlist_backend()
+                 << device_manager()
+                 << internet_services();
+
+  connect(collection(), SIGNAL(ExitFinished()), this, SLOT(ExitReceived()));
+  collection()->Exit();
+
+  connect(playlist_backend(), SIGNAL(ExitFinished()), this, SLOT(ExitReceived()));
+  playlist_backend()->ExitAsync();
+
+  connect(device_manager(), SIGNAL(ExitFinished()), this, SLOT(ExitReceived()));
+  device_manager()->Exit();
+
+  connect(internet_services(), SIGNAL(ExitFinished()), this, SLOT(ExitReceived()));
+  internet_services()->Exit();
+
+  database()->Close();
+
+}
+
+void Application::ExitReceived() {
+
+  disconnect(sender(), 0, this, 0);
+
+  wait_for_exit_.removeAll(sender());
+  if (wait_for_exit_.isEmpty()) emit ExitFinished();
+
+}
+
 void Application::AddError(const QString& message) { emit ErrorAdded(message); }
 void Application::ReloadSettings() { emit SettingsChanged(); }
 void Application::OpenSettingsDialogAtPage(SettingsDialog::Page page) { emit SettingsDialogRequested(page); }

src/core/application.h

@@ -111,9 +111,14 @@ class Application : public QObject {
   MoodbarLoader *moodbar_loader() const;
 #endif
 
-  void MoveToNewThread(QObject *object);
+  void Exit();
+
+  QThread *MoveToNewThread(QObject *object);
   void MoveToThread(QObject *object, QThread *thread);
 
+private slots:
+  void ExitReceived();
+
  public slots:
   void AddError(const QString &message);
   void ReloadSettings();
@@ -123,10 +128,12 @@ signals:
   void ErrorAdded(const QString &message);
   void SettingsChanged();
   void SettingsDialogRequested(SettingsDialog::Page page);
+  void ExitFinished();
 
  private:
   std::unique_ptr<ApplicationImpl> p_;
   QList<QThread*> threads_;
+  QList<QObject*> wait_for_exit_;
 
 };
 

src/core/database.cpp

@@ -211,6 +211,7 @@ int Database::FTSNext(sqlite3_tokenizer_cursor *cursor, const char* *token, int
 void Database::StaticInit() {
 
   if (sFTSTokenizer) return;
+
   sFTSTokenizer = new sqlite3_tokenizer_module;
   sFTSTokenizer->iVersion = 0;
   sFTSTokenizer->xCreate = &Database::FTSCreate;
@@ -242,7 +243,21 @@ Database::Database(Application *app, QObject *parent, const QString &database_na
 
 }
 
-Database::~Database() {}
+Database::~Database() {
+
+  QMutexLocker l(&connect_mutex_);
+
+  for (QString connection : connections_) {
+    qLog(Error) << connection << "still open!";
+  }
+
+  if (!connections_.isEmpty())
+    qLog(Error) << connections_.count() << "connections still open!";
+
+  if (sFTSTokenizer)
+    delete sFTSTokenizer;
+
+}
 
 QSqlDatabase Database::Connect() {
 
@@ -257,6 +272,11 @@ QSqlDatabase Database::Connect() {
 
   const QString connection_id = QString("%1_thread_%2").arg(connection_id_).arg(reinterpret_cast<quint64>(QThread::currentThread()));
 
+  if (!connections_.contains(connection_id)) {
+    //qLog(Debug) << "Opened database with connection id" << connection_id;
+    connections_ << connection_id;
+  }
+
   // Try to find an existing connection for this thread
   QSqlDatabase db = QSqlDatabase::database(connection_id);
   if (db.isOpen()) {
@@ -346,6 +366,25 @@ QSqlDatabase Database::Connect() {
 
 }
 
+void Database::Close() {
+
+  QMutexLocker l(&connect_mutex_);
+
+  const QString connection_id = QString("%1_thread_%2").arg(connection_id_).arg(reinterpret_cast<quint64>(QThread::currentThread()));
+
+  // Try to find an existing connection for this thread
+  QSqlDatabase db = QSqlDatabase::database(connection_id);
+  if (db.isOpen()) {
+    db.close();
+  }
+
+  if (connections_.contains(connection_id)) {
+    //qLog(Debug) << "Closed database with connection id" << connection_id;
+    connections_.removeAll(connection_id);
+  }
+
+}
+
 void Database::UpdateMainSchema(QSqlDatabase *db) {
 
   // Get the database's schema version

src/core/database.h

@@ -68,6 +68,7 @@ class Database : public QObject {
   static const char *kMagicAllSongsTables;
 
   QSqlDatabase Connect();
+  void Close();
   bool CheckErrors(const QSqlQuery &query);
   QMutex *Mutex() { return &mutex_; }
 
@@ -111,6 +112,7 @@ signals:
 
   // This ID makes the QSqlDatabase name unique to the object as well as the thread
   int connection_id_;
+  QStringList connections_;
 
   static QMutex sNextConnectionIdMutex;
   static int sNextConnectionId;

src/core/deletefiles.cpp

@@ -55,7 +55,7 @@ void DeleteFiles::Start(const SongList &songs) {
   task_id_ = task_manager_->StartTask(tr("Deleting files"));
   task_manager_->SetTaskBlocksCollectionScans(true);
 
-  thread_ = new QThread;
+  thread_ = new QThread(this);
   connect(thread_, SIGNAL(started()), SLOT(ProcessSomeFiles()));
 
   moveToThread(thread_);

src/core/mainwindow.cpp

@@ -989,7 +989,7 @@ void MainWindow::Exit() {
 
   if (app_->player()->engine()->is_fadeout_enabled()) {
     // To shut down the application when fadeout will be finished
-    connect(app_->player()->engine(), SIGNAL(FadeoutFinishedSignal()), qApp, SLOT(quit()));
+    connect(app_->player()->engine(), SIGNAL(FadeoutFinishedSignal()), this, SLOT(DoExit()));
     if (app_->player()->GetState() == Engine::Playing) {
       app_->player()->Stop();
       hide();
@@ -998,6 +998,19 @@ void MainWindow::Exit() {
     }
   }
 
+  DoExit();
+
+}
+
+void MainWindow::DoExit() {
+
+  connect(app_, SIGNAL(ExitFinished()), this, SLOT(ExitFinished()));
+  app_->Exit();
+
+}
+
+void MainWindow::ExitFinished() {
+
   qApp->quit();
 
 }

src/core/mainwindow.h

@@ -243,6 +243,7 @@ signals:
   void Raise();
 
   void Exit();
+  void DoExit();
 
   void HandleNotificationPreview(OSD::Behaviour type, QString line1, QString line2);
 
@@ -262,6 +263,8 @@ signals:
   void LoveButtonVisibilityChanged(bool value);
   void Love();
 
+  void ExitFinished();
+
  private:
 
   void SaveSettings();