Asynchronous settings saving

src/main.cpp

@@ -95,7 +95,7 @@ int main(int argc, char *argv[])
 #endif
 
     qsrand(time(0));
-
+    Settings::getInstance();
     Translator::translate();
 
     // Process arguments
@@ -110,7 +110,6 @@ int main(int argc, char *argv[])
 #ifndef Q_OS_ANDROID
     IPC::getInstance();
 #endif
-    Settings::getInstance(); // Build our Settings singleton as soon as QApplication is ready, not before
 
     if (parser.isSet("p"))
     {
@@ -272,6 +271,7 @@ int main(int argc, char *argv[])
 #endif
 
     Nexus::destroyInstance();
-
+    Settings::destroyInstance();
+    qDebug() << "Clean exit with status"<<errorcode;
     return errorcode;
 }

src/misc/settings.cpp

@@ -37,21 +37,34 @@
 #include <QStyleFactory>
 #include <QCryptographicHash>
 #include <QMutexLocker>
-
+#include <QThread>
 
 #define SHOW_SYSTEM_TRAY_DEFAULT (bool) true
 
 const QString Settings::globalSettingsFile = "qtox.ini";
 Settings* Settings::settings{nullptr};
 QMutex Settings::bigLock{QMutex::Recursive};
+QThread* Settings::settingsThread{nullptr};
 
 Settings::Settings() :
     loaded(false), useCustomDhtList{false},
     makeToxPortable{false}, currentProfileId(0)
 {
+    settingsThread = new QThread();
+    settingsThread->setObjectName("qTox Settings");
+    settingsThread->start(QThread::LowPriority);
+    moveToThread(settingsThread);
     load();
 }
 
+Settings::~Settings()
+{
+    sync();
+    settingsThread->exit(0);
+    settingsThread->wait();
+    delete settingsThread;
+}
+
 Settings& Settings::getInstance()
 {
     if (!settings)
@@ -60,6 +73,12 @@ Settings& Settings::getInstance()
     return *settings;
 }
 
+void Settings::destroyInstance()
+{
+    delete settings;
+    settings = nullptr;
+}
+
 void Settings::load()
 {
     QMutexLocker locker{&bigLock};
@@ -263,12 +282,20 @@ void Settings::load()
 
 void Settings::save(bool writePersonal)
 {
-    QString filePath = QDir(getSettingsDirPath()).filePath(globalSettingsFile);
+    if (QThread::currentThread() != settingsThread)
+        return (void) QMetaObject::invokeMethod(&getInstance(), "save",
+                                                Q_ARG(bool, writePersonal));
+
+    QString filePath = getSettingsDirPath()+globalSettingsFile;
     save(filePath, writePersonal);
 }
 
 void Settings::save(QString path, bool writePersonal)
 {
+    if (QThread::currentThread() != settingsThread)
+        return (void) QMetaObject::invokeMethod(&getInstance(), "save",
+                                                Q_ARG(QString, path), Q_ARG(bool, writePersonal));
+
 #ifndef Q_OS_ANDROID
     if (IPC::getInstance().isCurrentOwner())
 #endif
@@ -1289,3 +1316,15 @@ void Settings::createSettingsDir()
     if (!directory.exists() && !directory.mkpath(directory.absolutePath()))
         qCritical() << "Error while creating directory " << dir;
 }
+
+void Settings::sync()
+{
+    if (QThread::currentThread() != settingsThread)
+    {
+        QMetaObject::invokeMethod(&getInstance(), "sync", Qt::BlockingQueuedConnection);
+        return;
+    }
+
+    QMutexLocker locker{&bigLock};
+    qApp->processEvents();
+}

src/misc/settings.h

@@ -32,16 +32,18 @@ class Settings : public QObject
 {
     Q_OBJECT
 public:
-    ~Settings() = default;
     static Settings& getInstance();
+    static void destroyInstance();
     QString getSettingsDirPath(); ///< The returned path ends with a directory separator
 
     void createSettingsDir(); ///< Creates a path to the settings dir, if it doesn't already exist
     void createPersonal(QString basename); ///< Write a default personnal .ini settings file for a profile
 
+public slots:
     void load();
-    void save(bool writePersonal = true);
-    void save(QString path, bool writePersonal = true);
+    void save(bool writePersonal = true); ///< Asynchronous
+    void save(QString path, bool writePersonal = true); ///< Asynchronous
+    void sync(); ///< Waits for all asynchronous operations to complete
 
 signals:
     void dhtServerListChanged();
@@ -254,6 +256,7 @@ public:
 
 private:
     Settings();
+    ~Settings();
     Settings(Settings &settings) = delete;
     Settings& operator=(const Settings&) = delete;
     static uint32_t makeProfileId(const QString& profile);
@@ -352,6 +355,7 @@ private:
     static QMutex bigLock;
     static Settings* settings;
     static const QString globalSettingsFile;
+    static QThread* settingsThread;
 };
 
 #endif // SETTINGS_HPP