safer database cleanups

Author: Skycoder42

src/datasync/datasync.pro

@@ -1,7 +1,7 @@
 TARGET = QtDataSync
 
 QT = core jsonserializer sql websockets scxml remoteobjects remoteobjects-private
-android: QT += androidextras #needed to deploy the android keystore plugin
+#android: QT += androidextras #needed to deploy the android keystore plugin
 
 HEADERS += \
 	qtdatasync_global.h \

src/datasync/defaults.cpp

@@ -192,7 +192,7 @@ QSqlDatabase *DatabaseRef::operator->() const
 const QString DefaultsPrivate::DatabaseName(QStringLiteral("__QtDataSync_database_%1_0x%2"));
 QMutex DefaultsPrivate::setupDefaultsMutex;
 QHash<QString, QSharedPointer<DefaultsPrivate>> DefaultsPrivate::setupDefaults;
-QThreadStorage<QHash<QString, quint64>> DefaultsPrivate::dbRefHash;
+thread_local DefaultsPrivate::DatabaseHolder DefaultsPrivate::dbRefHash;
 
 void DefaultsPrivate::createDefaults(const QString &setupName, bool isPassive, const QDir &storageDir, const QUrl &roAddress, const QHash<Defaults::PropertyKey, QVariant> &properties, QJsonSerializer *serializer, ConflictResolver *resolver)
 {
@@ -287,7 +287,7 @@ QSqlDatabase DefaultsPrivate::acquireDatabase()
 {
 	auto name = DefaultsPrivate::DatabaseName
 				.arg(setupName, QString::number(reinterpret_cast<quint64>(QThread::currentThread()), 16));
-	if((dbRefHash.localData()[setupName])++ == 0) {
+	if((dbRefHash[setupName])++ == 0) {
 		logDebug() << "Acquiring database for thread" << QThread::currentThread();
 		auto database = QSqlDatabase::addDatabase(QStringLiteral("QSQLITE"), name);
 		database.setDatabaseName(storageDir.absoluteFilePath(QStringLiteral("store.db")));
@@ -331,12 +331,9 @@ QSqlDatabase DefaultsPrivate::acquireDatabase()
 
 void DefaultsPrivate::releaseDatabase()
 {
-	if(--(dbRefHash.localData()[setupName]) == 0) {
+	if(--(dbRefHash[setupName]) == 0) {
 		logDebug() << "Releasing database for thread" << QThread::currentThread();
-		auto name = DefaultsPrivate::DatabaseName
-					.arg(setupName, QString::number(reinterpret_cast<quint64>(QThread::currentThread()), 16));
-		QSqlDatabase::database(name).close();
-		QSqlDatabase::removeDatabase(name);
+		releaseDatabaseImpl(setupName);
 	}
 }
 
@@ -385,6 +382,29 @@ void DefaultsPrivate::makePassive()
 	}
 }
 
+void DefaultsPrivate::releaseDatabaseImpl(const QString &name)
+{
+	auto dbName = DefaultsPrivate::DatabaseName
+				  .arg(name, QString::number(reinterpret_cast<quint64>(QThread::currentThread()), 16));
+	QSqlDatabase::database(dbName).close();
+	QSqlDatabase::removeDatabase(dbName);
+}
+
+
+
+DefaultsPrivate::DatabaseHolder::~DatabaseHolder()
+{
+	for(auto it = constBegin(); it != constEnd(); it++) {
+		if(*it <= 0)
+			continue;
+		qCCritical(qdssetup) << "Setup" << it.key()
+							 << "still has" << *it
+							 << "open database references in thread" << QThread::currentThread()
+							 << "on destruction of that thread! Database will be force-closed";
+		releaseDatabaseImpl(it.key());
+	}
+}
+
 // ------------- PRIVATE IMPLEMENTATION DatabaseRef -------------
 
 DatabaseRefPrivate::DatabaseRefPrivate(QSharedPointer<DefaultsPrivate> defaultsPrivate, QObject *object) :

src/datasync/defaults_p.h

@@ -80,9 +80,16 @@ private Q_SLOTS:
 	void makePassive();
 
 private:
+	static void releaseDatabaseImpl(const QString &name);
+
+	struct DatabaseHolder : public QHash<QString, quint64>
+	{
+		~DatabaseHolder();
+	};
+
 	static QMutex setupDefaultsMutex;
 	static QHash<QString, QSharedPointer<DefaultsPrivate>> setupDefaults;
-	static QThreadStorage<QHash<QString, quint64>> dbRefHash;
+	static thread_local DatabaseHolder dbRefHash;
 
 	QString setupName;
 	QDir storageDir;

src/datasync/exchangeengine.cpp

@@ -342,18 +342,15 @@ ExchangeEngine::ImportData::ImportData(QJsonObject data, QString password, bool
 
 // ------------- Engine Thread -------------
 
+thread_local QSharedPointer<EngineThread> EngineThread::_deleteBlocker;
+
 EngineThread::EngineThread(QString setupName, ExchangeEngine *engine, QLockFile *lockFile) :
 	_name{std::move(setupName)},
 	_engine{engine},
 	_lockFile{lockFile}
 {
 	setTerminationEnabled(true);
 	_engine.load()->moveToThread(this);
-
-	connect(this, &QThread::finished,
-			this, [this](){
-		_deleteBlocker.clear();
-	}, Qt::QueuedConnection);
 }
 
 EngineThread::~EngineThread()

src/datasync/exchangeengine_p.h

@@ -145,7 +145,7 @@ class EngineThread : public QThread
 	QAtomicInteger<quint16> _running = false;
 
 	//delete blocker
-	QSharedPointer<EngineThread> _deleteBlocker;
+	static thread_local QSharedPointer<EngineThread> _deleteBlocker;
 };
 
 }

src/datasync/setup.cpp

@@ -608,7 +608,7 @@ SetupPrivate::SetupPrivate() :
 
 void SetupPrivate::deleteThread(EngineThread *thread)
 {
-	thread->deleteLater();
+	delete thread;
 }
 
 // ------------- Exceptions -------------