Safely close database connections and delete backends

Also fix NewClosure leak caused by disconnected object signals

src/tidal/tidalbaserequest.cpp

@@ -52,7 +52,7 @@ TidalBaseRequest::~TidalBaseRequest() {
 
   while (!replies_.isEmpty()) {
     QNetworkReply *reply = replies_.takeFirst();
-    disconnect(reply, 0, nullptr, 0);
+    disconnect(reply, 0, this, 0);
     if (reply->isRunning()) reply->abort();
     reply->deleteLater();
   }

src/tidal/tidalfavoriterequest.cpp

@@ -50,7 +50,7 @@ TidalFavoriteRequest::~TidalFavoriteRequest() {
 
   while (!replies_.isEmpty()) {
     QNetworkReply *reply = replies_.takeFirst();
-    disconnect(reply, 0, nullptr, 0);
+    disconnect(reply, 0, this, 0);
     reply->abort();
     reply->deleteLater();
   }

src/tidal/tidalrequest.cpp

@@ -80,7 +80,7 @@ TidalRequest::~TidalRequest() {
 
   while (!album_cover_replies_.isEmpty()) {
     QNetworkReply *reply = album_cover_replies_.takeFirst();
-    disconnect(reply, 0, nullptr, 0);
+    disconnect(reply, 0, this, 0);
     if (reply->isRunning()) reply->abort();
     reply->deleteLater();
   }

src/tidal/tidalservice.cpp

@@ -182,13 +182,35 @@ TidalService::~TidalService() {
 
   while (!stream_url_requests_.isEmpty()) {
     TidalStreamURLRequest *stream_url_req = stream_url_requests_.takeFirst();
-    disconnect(stream_url_req, 0, nullptr, 0);
+    disconnect(stream_url_req, 0, this, 0);
     stream_url_req->deleteLater();
   }
 
-  artists_collection_backend_->deleteLater();
-  albums_collection_backend_->deleteLater();
-  songs_collection_backend_->deleteLater();
+  delete artists_collection_backend_;
+  delete albums_collection_backend_;
+  delete songs_collection_backend_;
+
+}
+
+void TidalService::Exit() {
+
+  wait_for_exit_ << artists_collection_backend_ << albums_collection_backend_ << songs_collection_backend_;
+
+  connect(artists_collection_backend_, SIGNAL(ExitFinished()), this, SLOT(ExitReceived()));
+  connect(albums_collection_backend_, SIGNAL(ExitFinished()), this, SLOT(ExitReceived()));
+  connect(songs_collection_backend_, SIGNAL(ExitFinished()), this, SLOT(ExitReceived()));
+
+  artists_collection_backend_->ExitAsync();
+  albums_collection_backend_->ExitAsync();
+  songs_collection_backend_->ExitAsync();
+
+}
+
+void TidalService::ExitReceived() {
+
+  disconnect(sender(), 0, this, 0);
+  wait_for_exit_.removeAll(sender());
+  if (wait_for_exit_.isEmpty()) emit ExitFinished();
 
 }
 
@@ -639,7 +661,7 @@ void TidalService::TryLogin() {
 void TidalService::ResetArtistsRequest() {
 
   if (artists_request_.get()) {
-    disconnect(artists_request_.get(), 0, nullptr, 0);
+    disconnect(artists_request_.get(), 0, this, 0);
     disconnect(this, 0, artists_request_.get(), 0);
     artists_request_.reset();
   }
@@ -694,7 +716,7 @@ void TidalService::ArtistsUpdateProgressReceived(const int id, const int progres
 void TidalService::ResetAlbumsRequest() {
 
   if (albums_request_.get()) {
-    disconnect(albums_request_.get(), 0, nullptr, 0);
+    disconnect(albums_request_.get(), 0, this, 0);
     disconnect(this, 0, albums_request_.get(), 0);
     albums_request_.reset();
   }
@@ -747,7 +769,7 @@ void TidalService::AlbumsUpdateProgressReceived(const int id, const int progress
 void TidalService::ResetSongsRequest() {
 
   if (songs_request_.get()) {
-    disconnect(songs_request_.get(), 0, nullptr, 0);
+    disconnect(songs_request_.get(), 0, this, 0);
     disconnect(this, 0, songs_request_.get(), 0);
     songs_request_.reset();
   }

src/tidal/tidalservice.h

@@ -61,6 +61,7 @@ class TidalService : public InternetService {
 
   static const Song::Source kSource;
 
+  void Exit();
   void ReloadSettings();
 
   void Logout();
@@ -132,6 +133,7 @@ class TidalService : public InternetService {
   void ResetSongsRequest();
 
  private slots:
+  void ExitReceived();
   void StartAuthorisation();
   void AuthorisationUrlReceived(const QUrl &url);
   void HandleLoginSSLErrors(QList<QSslError> ssl_errors);
@@ -245,6 +247,8 @@ class TidalService : public InternetService {
 
   QStringList login_errors_;
 
+  QList<QObject*> wait_for_exit_;
+
 };
 
 #endif  // TIDALSERVICE_H

src/tidal/tidalstreamurlrequest.cpp

@@ -52,7 +52,7 @@ TidalStreamURLRequest::TidalStreamURLRequest(TidalService *service, NetworkAcces
 TidalStreamURLRequest::~TidalStreamURLRequest() {
 
   if (reply_) {
-    disconnect(reply_, 0, nullptr, 0);
+    disconnect(reply_, 0, this, 0);
     if (reply_->isRunning()) reply_->abort();
     reply_->deleteLater();
   }
@@ -109,7 +109,7 @@ void TidalStreamURLRequest::GetStreamURL() {
   ++tries_;
 
   if (reply_) {
-    disconnect(reply_, 0, nullptr, 0);
+    disconnect(reply_, 0, this, 0);
     if (reply_->isRunning()) reply_->abort();
     reply_->deleteLater();
   }
@@ -144,7 +144,7 @@ void TidalStreamURLRequest::GetStreamURL() {
 void TidalStreamURLRequest::StreamURLReceived() {
 
   if (!reply_) return;
-  disconnect(reply_, 0, nullptr, 0);
+  disconnect(reply_, 0, this, 0);
   reply_->deleteLater();
 
   QByteArray data = GetReplyData(reply_, true);