QPA: Fix semantics of GUI event dispatcher ownership in platform plugins

The QPlatformIntegration::guiThreadEventDispatcher() function acted as an
accessor to event dispatchers created in the constructor of each platform
plugin, but the logic and semantics of event-dispatcher handling in Qt
itself (QCoreApplication/QGuiApplication) still assumed both ownership
and control over the event dispatcher, such as when to create one, which
one to create, and when to delete it. This conflicted with the explicit
calls in the platform plugins to QGuiApplication::setEventDispatcher(),
as well as left a possibility that the event-dispatcher created by
the platform plugin would never be deleted, as none of the platform
plugins actually took full ownership of the dispatcher and deleted it
in its destructor.

The integration function has now been renamed back to its old name,
createEventDispatcher(), and acts as a factory function, leaving
the logic and lifetime of event dispatcher to QtCoreApplication.

The only platform left with creating the event-dispatcher in the
constructor is QNX, where other parts of the platform relies on
having an event-dispatcher before their initialization. We then
need to manually take care of the ownership transfer, so that the
event-dispatcher is still destroyed at some point.

Change-Id: I113db97d2545ebda39ebdefa865e488d2ce9368b
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

src/gui/kernel/qguiapplication.cpp

@@ -1029,27 +1029,23 @@ void QGuiApplicationPrivate::createPlatformIntegration()
 
 }
 
+/*!
+    Called from QCoreApplication::init()
+
+    Responsible for creating an event dispatcher when QCoreApplication
+    decides that it needs one (because a custom one has not been set).
+*/
 void QGuiApplicationPrivate::createEventDispatcher()
 {
+    Q_ASSERT(!eventDispatcher);
+
     if (platform_integration == 0)
         createPlatformIntegration();
 
-    if (!eventDispatcher) {
-        QAbstractEventDispatcher *eventDispatcher = platform_integration->guiThreadEventDispatcher();
-        setEventDispatcher(eventDispatcher);
-    }
-}
-
-void QGuiApplicationPrivate::setEventDispatcher(QAbstractEventDispatcher *eventDispatcher)
-{
-    Q_Q(QGuiApplication);
-
-    if (!QCoreApplicationPrivate::eventDispatcher) {
-        QCoreApplicationPrivate::eventDispatcher = eventDispatcher;
-        QCoreApplicationPrivate::eventDispatcher->setParent(q);
-        threadData->eventDispatcher = eventDispatcher;
-    }
+    // The platform integration should not mess with the event dispatcher
+    Q_ASSERT(!eventDispatcher);
 
+    eventDispatcher = platform_integration->createEventDispatcher();
 }
 
 #if defined(QT_DEBUG) && defined(Q_OS_LINUX)

src/gui/kernel/qguiapplication_p.h

@@ -83,8 +83,7 @@ public:
     ~QGuiApplicationPrivate();
 
     void createPlatformIntegration();
-    void createEventDispatcher();
-    void setEventDispatcher(QAbstractEventDispatcher *eventDispatcher);
+    void createEventDispatcher() Q_DECL_OVERRIDE;
 
     virtual void notifyLayoutDirectionChange();
     virtual void notifyActiveWindowChange(QWindow *previous);

src/gui/kernel/qplatformintegration.cpp

@@ -231,17 +231,23 @@ QPlatformServices *QPlatformIntegration::services() const
     are never repositioned by the window manager. The default implementation returns true.
  */
 
-
 /*!
 
-    \fn QAbstractEventDispatcher *QPlatformIntegration::guiThreadEventDispatcher() const = 0
+    \fn QAbstractEventDispatcher *QPlatformIntegration::createEventDispatcher() const = 0
 
-    Accessor function for the event dispatcher. The platform plugin should create
-    an instance of the QAbstractEventDispatcher in its constructor and set it
-    on the application using QGuiApplicationPrivate::instance()->setEventDispatcher().
-    The event dispatcher is owned by QGuiApplication, the accessor should return
-    a flat pointer.
-    \sa QGuiApplicationPrivate
+    Factory function for the GUI event dispatcher. The platform plugin should create
+    and return a QAbstractEventDispatcher subclass when this function is called.
+
+    If the platform plugin for some reason creates the event dispatcher outside of
+    this function (for example in the constructor), it needs to handle the case
+    where this function is never called, ensuring that the event dispatcher is
+    still deleted at some point (typically in the destructor).
+
+    Note that the platform plugin should never explicitly set the event dispatcher
+    itself, using QCoreApplication::setEventDispatcher(), but let QCoreApplication
+    decide when and which event dispatcher to create.
+
+    \since 5.2
 */
 
 bool QPlatformIntegration::hasCapability(Capability cap) const

src/gui/kernel/qplatformintegration.h

@@ -111,7 +111,7 @@ public:
     virtual QPaintEngine *createImagePaintEngine(QPaintDevice *paintDevice) const;
 
 // Event dispatcher:
-    virtual QAbstractEventDispatcher *guiThreadEventDispatcher() const = 0;
+    virtual QAbstractEventDispatcher *createEventDispatcher() const = 0;
 
 //Deeper window system integrations
     virtual QPlatformFontDatabase *fontDatabase() const;

src/plugins/platforms/android/src/qandroidplatformintegration.cpp

@@ -100,10 +100,6 @@ QAndroidPlatformIntegration::QAndroidPlatformIntegration(const QStringList &para
 {
     Q_UNUSED(paramList);
 
-#ifndef ANDROID_PLUGIN_OPENGL
-    m_eventDispatcher = createUnixEventDispatcher();
-#endif
-
     m_androidPlatformNativeInterface = new QAndroidPlatformNativeInterface();
 
 #ifndef ANDROID_PLUGIN_OPENGL
@@ -150,9 +146,9 @@ QPlatformWindow *QAndroidPlatformIntegration::createPlatformWindow(QWindow *wind
     return new QAndroidPlatformWindow(window);
 }
 
-QAbstractEventDispatcher *QAndroidPlatformIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QAndroidPlatformIntegration::createEventDispatcher() const
 {
-    return m_eventDispatcher;
+    return createUnixEventDispatcher();
 }
 #else // !ANDROID_PLUGIN_OPENGL
 QPlatformWindow *QAndroidPlatformIntegration::createPlatformWindow(QWindow *window) const

src/plugins/platforms/android/src/qandroidplatformintegration.h

@@ -93,7 +93,7 @@ public:
 #ifndef ANDROID_PLUGIN_OPENGL
     QPlatformBackingStore *createPlatformBackingStore(QWindow *window) const;
     QPlatformWindow *createPlatformWindow(QWindow *window) const;
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
     QAndroidPlatformScreen *screen() { return m_primaryScreen; }
 #else
     QPlatformWindow *createPlatformWindow(QWindow *window) const;
@@ -147,7 +147,6 @@ private:
     QTouchDevice *m_touchDevice;
 
 #ifndef ANDROID_PLUGIN_OPENGL
-    QAbstractEventDispatcher *m_eventDispatcher;
     QAndroidPlatformScreen *m_primaryScreen;
 #endif
 

src/plugins/platforms/cocoa/qcocoaintegration.h

@@ -108,7 +108,7 @@ public:
     QPlatformOpenGLContext *createPlatformOpenGLContext(QOpenGLContext *context) const;
     QPlatformBackingStore *createPlatformBackingStore(QWindow *widget) const;
 
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
     QPlatformFontDatabase *fontDatabase() const;
 
     QPlatformNativeInterface *nativeInterface() const;
@@ -130,7 +130,6 @@ public:
 private:
 
     QScopedPointer<QPlatformFontDatabase> mFontDb;
-    QAbstractEventDispatcher *mEventDispatcher;
 
     QScopedPointer<QPlatformInputContext> mInputContext;
 #ifndef QT_NO_ACCESSIBILITY

src/plugins/platforms/cocoa/qcocoaintegration.mm

@@ -216,7 +216,6 @@ QPixmap QCocoaScreen::grabWindow(WId window, int x, int y, int width, int height
 
 QCocoaIntegration::QCocoaIntegration()
     : mFontDb(new QCoreTextFontDatabase())
-    , mEventDispatcher(new QCocoaEventDispatcher())
     , mInputContext(new QCocoaInputContext)
 #ifndef QT_NO_ACCESSIBILITY
     , mAccessibility(new QCocoaAccessibility)
@@ -384,9 +383,9 @@ QPlatformBackingStore *QCocoaIntegration::createPlatformBackingStore(QWindow *wi
     return new QCocoaBackingStore(window);
 }
 
-QAbstractEventDispatcher *QCocoaIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QCocoaIntegration::createEventDispatcher() const
 {
-    return mEventDispatcher;
+    return new QCocoaEventDispatcher;
 }
 
 QPlatformFontDatabase *QCocoaIntegration::fontDatabase() const

src/plugins/platforms/directfb/qdirectfbintegration.cpp

@@ -61,9 +61,7 @@ QT_BEGIN_NAMESPACE
 
 QDirectFbIntegration::QDirectFbIntegration()
     : m_fontDb(new QGenericUnixFontDatabase())
-    , m_eventDispatcher(createUnixEventDispatcher())
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(m_eventDispatcher);
 }
 
 void QDirectFbIntegration::initialize()
@@ -129,9 +127,9 @@ QPlatformWindow *QDirectFbIntegration::createPlatformWindow(QWindow *window) con
     return dfbWindow;
 }
 
-QAbstractEventDispatcher *QDirectFbIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QDirectFbIntegration::createEventDispatcher() const
 {
-    return m_eventDispatcher;
+    return createUnixEventDispatcher();
 }
 
 QPlatformBackingStore *QDirectFbIntegration::createPlatformBackingStore(QWindow *window) const

src/plugins/platforms/directfb/qdirectfbintegration.h

@@ -65,7 +65,7 @@ public:
     QPlatformPixmap *createPlatformPixmap(QPlatformPixmap::PixelType type) const;
     QPlatformWindow *createPlatformWindow(QWindow *window) const;
     QPlatformBackingStore *createPlatformBackingStore(QWindow *window) const;
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     QPlatformFontDatabase *fontDatabase() const;
 
@@ -80,7 +80,6 @@ protected:
     QScopedPointer<QDirectFbInput> m_input;
     QScopedPointer<QThread> m_inputRunner;
     QScopedPointer<QPlatformFontDatabase> m_fontDb;
-    QAbstractEventDispatcher *m_eventDispatcher;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/eglfs/qeglfsintegration.cpp

@@ -78,12 +78,9 @@ QT_BEGIN_NAMESPACE
 static void *eglContextForContext(QOpenGLContext *context);
 
 QEglFSIntegration::QEglFSIntegration()
-    : mEventDispatcher(createUnixEventDispatcher()),
-      mFontDb(new QGenericUnixFontDatabase),
-      mServices(new QGenericUnixServices)
+    : mFontDb(new QGenericUnixFontDatabase)
+    , mServices(new QGenericUnixServices)
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(mEventDispatcher);
-
 #if !defined(QT_NO_EVDEV) && (!defined(Q_OS_ANDROID) || defined(Q_OS_ANDROID_NO_SDK))
     new QEvdevKeyboardManager(QLatin1String("EvdevKeyboard"), QString() /* spec */, this);
     new QEvdevMouseManager(QLatin1String("EvdevMouse"), QString() /* spec */, this);
@@ -168,9 +165,9 @@ QPlatformFontDatabase *QEglFSIntegration::fontDatabase() const
     return mFontDb.data();
 }
 
-QAbstractEventDispatcher *QEglFSIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QEglFSIntegration::createEventDispatcher() const
 {
-    return mEventDispatcher;
+    return createUnixEventDispatcher();
 }
 
 QVariant QEglFSIntegration::styleHint(QPlatformIntegration::StyleHint hint) const

src/plugins/platforms/eglfs/qeglfsintegration.h

@@ -67,7 +67,7 @@ public:
     QPlatformFontDatabase *fontDatabase() const;
     QPlatformServices *services() const;
 
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     QVariant styleHint(QPlatformIntegration::StyleHint hint) const;
 
@@ -87,7 +87,6 @@ public:
 
 private:
     EGLDisplay mDisplay;
-    QAbstractEventDispatcher *mEventDispatcher;
     QScopedPointer<QPlatformFontDatabase> mFontDb;
     QScopedPointer<QPlatformServices> mServices;
     QEglFSScreen *mScreen;

src/plugins/platforms/ios/qiosintegration.h

@@ -70,7 +70,7 @@ public:
     QStringList themeNames() const;
     QPlatformTheme *createPlatformTheme(const QString &name) const;
 
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
     QPlatformNativeInterface *nativeInterface() const;
 
     void *nativeResourceForWindow(const QByteArray &resource, QWindow *window);

src/plugins/platforms/ios/qiosintegration.mm

@@ -113,7 +113,7 @@ QPlatformOpenGLContext *QIOSIntegration::createPlatformOpenGLContext(QOpenGLCont
     return new QIOSContext(context);
 }
 
-QAbstractEventDispatcher *QIOSIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QIOSIntegration::createEventDispatcher() const
 {
     if (isQtApplication())
         return new QIOSEventDispatcher;

src/plugins/platforms/kms/qkmsintegration.cpp

@@ -65,10 +65,8 @@ QT_BEGIN_NAMESPACE
 QKmsIntegration::QKmsIntegration()
     : QPlatformIntegration(),
       m_fontDatabase(new QGenericUnixFontDatabase()),
-      m_eventDispatcher(createUnixEventDispatcher()),
       m_nativeInterface(new QKmsNativeInterface)
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(m_eventDispatcher);
     setenv("EGL_PLATFORM", "drm",1);
     m_vtHandler = new QKmsVTHandler;
 
@@ -152,9 +150,9 @@ void QKmsIntegration::addScreen(QKmsScreen *screen)
     screenAdded(screen);
 }
 
-QAbstractEventDispatcher *QKmsIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QKmsIntegration::createEventDispatcher() const
 {
-    return m_eventDispatcher;
+    return createUnixEventDispatcher();
 }
 
 QPlatformNativeInterface *QKmsIntegration::nativeInterface() const

src/plugins/platforms/kms/qkmsintegration.h

@@ -67,7 +67,7 @@ public:
     QPlatformBackingStore *createPlatformBackingStore(QWindow *window) const;
 
     QPlatformFontDatabase *fontDatabase() const;
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     QPlatformNativeInterface *nativeInterface() const;
 
@@ -84,7 +84,6 @@ private:
     QList<QPlatformScreen *> m_screens;
     QList<QKmsDevice *> m_devices;
     QPlatformFontDatabase *m_fontDatabase;
-    QAbstractEventDispatcher *m_eventDispatcher;
     QPlatformNativeInterface *m_nativeInterface;
     QKmsVTHandler *m_vtHandler;
     QDeviceDiscovery *m_deviceDiscovery;

src/plugins/platforms/linuxfb/qlinuxfbintegration.cpp

@@ -54,11 +54,8 @@
 QT_BEGIN_NAMESPACE
 
 QLinuxFbIntegration::QLinuxFbIntegration(const QStringList &paramList)
-    : m_fontDb(new QGenericUnixFontDatabase()),
-      m_eventDispatcher(createUnixEventDispatcher())
+    : m_fontDb(new QGenericUnixFontDatabase())
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(m_eventDispatcher);
-
     m_primaryScreen = new QLinuxFbScreen;
     if (m_primaryScreen->initialize(paramList))
         screenAdded(m_primaryScreen);
@@ -92,9 +89,9 @@ QPlatformWindow *QLinuxFbIntegration::createPlatformWindow(QWindow *window) cons
     return new QFbWindow(window);
 }
 
-QAbstractEventDispatcher *QLinuxFbIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QLinuxFbIntegration::createEventDispatcher() const
 {
-    return m_eventDispatcher;
+    return createUnixEventDispatcher();
 }
 
 QList<QPlatformScreen *> QLinuxFbIntegration::screens() const

src/plugins/platforms/linuxfb/qlinuxfbintegration.h

@@ -61,14 +61,13 @@ public:
     QPlatformPixmap *createPlatformPixmap(QPlatformPixmap::PixelType type) const;
     QPlatformWindow *createPlatformWindow(QWindow *window) const;
     QPlatformBackingStore *createPlatformBackingStore(QWindow *window) const;
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
     QList<QPlatformScreen *> screens() const;
     QPlatformFontDatabase *fontDatabase() const;
 
 private:
     QLinuxFbScreen *m_primaryScreen;
     QPlatformFontDatabase *m_fontDb;
-    QAbstractEventDispatcher *m_eventDispatcher;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/minimal/qminimalintegration.cpp

@@ -53,14 +53,8 @@
 
 QT_BEGIN_NAMESPACE
 
-QMinimalIntegration::QMinimalIntegration() :
-#ifdef Q_OS_WIN
-    m_eventDispatcher(new QEventDispatcherWin32())
-#else
-    m_eventDispatcher(createUnixEventDispatcher())
-#endif
+QMinimalIntegration::QMinimalIntegration()
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(m_eventDispatcher);
     QMinimalScreen *mPrimaryScreen = new QMinimalScreen();
 
     mPrimaryScreen->mGeometry = QRect(0, 0, 240, 320);
@@ -92,9 +86,13 @@ QPlatformBackingStore *QMinimalIntegration::createPlatformBackingStore(QWindow *
     return new QMinimalBackingStore(window);
 }
 
-QAbstractEventDispatcher *QMinimalIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QMinimalIntegration::createEventDispatcher() const
 {
-    return m_eventDispatcher;
+#ifdef Q_OS_WIN
+    return new QEventDispatcherWin32;
+#else
+    return createUnixEventDispatcher();
+#endif
 }
 
 QT_END_NAMESPACE

src/plugins/platforms/minimal/qminimalintegration.h

@@ -73,10 +73,7 @@ public:
 
     QPlatformWindow *createPlatformWindow(QWindow *window) const;
     QPlatformBackingStore *createPlatformBackingStore(QWindow *window) const;
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
-
-private:
-    QAbstractEventDispatcher *m_eventDispatcher;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/minimalegl/qminimaleglintegration.cpp

@@ -110,7 +110,7 @@ QPlatformFontDatabase *QMinimalEglIntegration::fontDatabase() const
     return mFontDb;
 }
 
-QAbstractEventDispatcher *QMinimalEglIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QMinimalEglIntegration::createEventDispatcher() const
 {
     return createUnixEventDispatcher();
 }

src/plugins/platforms/minimalegl/qminimaleglintegration.h

@@ -63,7 +63,7 @@ public:
 
     QPlatformFontDatabase *fontDatabase() const;
 
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     QVariant styleHint(QPlatformIntegration::StyleHint hint) const;
 

src/plugins/platforms/offscreen/qoffscreenintegration.cpp

@@ -95,14 +95,12 @@ public:
 QOffscreenIntegration::QOffscreenIntegration()
 {
 #if defined(Q_OS_UNIX)
-    m_eventDispatcher = createUnixEventDispatcher();
 #if defined(Q_OS_MAC)
     m_fontDatabase.reset(new QPlatformFontDatabase());
 #else
     m_fontDatabase.reset(new QGenericUnixFontDatabase());
 #endif
 #elif defined(Q_OS_WIN)
-    m_eventDispatcher = new QOffscreenEventDispatcher<QEventDispatcherWin32>();
     m_fontDatabase.reset(new QBasicFontDatabase());
 #endif
 
@@ -111,7 +109,6 @@ QOffscreenIntegration::QOffscreenIntegration()
 #endif
     m_services.reset(new QPlatformServices);
 
-    QGuiApplicationPrivate::instance()->setEventDispatcher(m_eventDispatcher);
     screenAdded(new QOffscreenScreen);
 }
 
@@ -141,9 +138,15 @@ QPlatformBackingStore *QOffscreenIntegration::createPlatformBackingStore(QWindow
     return new QOffscreenBackingStore(window);
 }
 
-QAbstractEventDispatcher *QOffscreenIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QOffscreenIntegration::createEventDispatcher() const
 {
-    return m_eventDispatcher;
+#if defined(Q_OS_UNIX)
+    return createUnixEventDispatcher();
+#elif defined(Q_OS_WIN)
+    return new QOffscreenEventDispatcher<QEventDispatcherWin32>();
+#else
+    return 0;
+#endif
 }
 
 QPlatformFontDatabase *QOffscreenIntegration::fontDatabase() const

src/plugins/platforms/offscreen/qoffscreenintegration.h

@@ -66,12 +66,11 @@ public:
     QPlatformServices *services() const;
 
     QPlatformFontDatabase *fontDatabase() const;
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     static QOffscreenIntegration *createOffscreenIntegration();
 
 private:
-    QAbstractEventDispatcher *m_eventDispatcher;
     QScopedPointer<QPlatformFontDatabase> m_fontDatabase;
 #ifndef QT_NO_DRAGANDDROP
     QScopedPointer<QPlatformDrag> m_drag;

src/plugins/platforms/openwfd/qopenwfdintegration.cpp

@@ -63,9 +63,7 @@
 QOpenWFDIntegration::QOpenWFDIntegration()
     : QPlatformIntegration()
     , mPrinterSupport(new QGenericUnixPrinterSupport)
-    , mEventDispatcher(createUnixEventDispatcher())
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(mEventDispatcher);
     int numberOfDevices = wfdEnumerateDevices(0,0,0);
 
     WFDint devices[numberOfDevices];
@@ -119,9 +117,9 @@ QPlatformBackingStore *QOpenWFDIntegration::createPlatformBackingStore(QWindow *
     return new QOpenWFDBackingStore(window);
 }
 
-QAbstractEventDispatcher *QOpenWFDIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QOpenWFDIntegration::createEventDispatcher() const
 {
-    return mEventDispatcher;
+    return createUnixEventDispatcher();
 }
 
 QPlatformFontDatabase *QOpenWFDIntegration::fontDatabase() const

src/plugins/platforms/openwfd/qopenwfdintegration.h

@@ -62,7 +62,7 @@ public:
     QPlatformOpenGLContext *createPlatformOpenGLContext(QOpenGLContext *context) const;
 
     //This should not be a factory interface, but rather a accessor
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     QPlatformFontDatabase *fontDatabase() const;
 
@@ -78,7 +78,6 @@ private:
     QPlatformFontDatabase *mFontDatabase;
     QPlatformNativeInterface *mNativeInterface;
     QPlatformPrinterSupport *mPrinterSupport;
-    QAbstractEventDispatcher *mEventDispatcher;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/qnx/qqnxintegration.cpp

@@ -294,6 +294,9 @@ QQnxIntegration::~QQnxIntegration()
     delete m_bpsEventFilter;
 #endif
 
+    // In case the event-dispatcher was never transferred to QCoreApplication
+    delete m_eventDispatcher;
+
     delete m_screenEventHandler;
 
     // Destroy all displays
@@ -386,10 +389,15 @@ void QQnxIntegration::moveToScreen(QWindow *window, int screen)
     platformWindow->setScreen(platformScreen);
 }
 
-QAbstractEventDispatcher *QQnxIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QQnxIntegration::createEventDispatcher() const
 {
     qIntegrationDebug() << Q_FUNC_INFO;
-    return m_eventDispatcher;
+
+    // We transfer ownersip of the event-dispatcher to QtCoreApplication
+    QAbstractEventDispatcher *eventDispatcher = m_eventDispatcher;
+    m_eventDispatcher = 0;
+
+    return eventDispatcher;
 }
 
 QPlatformNativeInterface *QQnxIntegration::nativeInterface() const

src/plugins/platforms/qnx/qqnxintegration.h

@@ -107,7 +107,7 @@ public:
 
     bool supportsNavigatorEvents() const;
 
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     QPlatformFontDatabase *fontDatabase() const { return m_fontDatabase; }
 
@@ -158,7 +158,7 @@ private:
 #endif
     QQnxServices *m_services;
     QPlatformFontDatabase *m_fontDatabase;
-    QAbstractEventDispatcher *m_eventDispatcher;
+    mutable QAbstractEventDispatcher *m_eventDispatcher;
 #if defined(Q_OS_BLACKBERRY)
     QQnxBpsEventFilter *m_bpsEventFilter;
 #endif

src/plugins/platforms/windows/qwindowsintegration.cpp

@@ -315,7 +315,6 @@ struct QWindowsIntegrationPrivate
     QWindowsDrag m_drag;
 #  endif
 #endif
-    QWindowsGuiEventDispatcher *m_eventDispatcher;
 #if defined(QT_OPENGL_ES_2)
     QEGLStaticContextPtr m_staticEGLContext;
 #elif !defined(QT_NO_OPENGL)
@@ -356,7 +355,6 @@ static inline unsigned parseOptions(const QStringList &paramList)
 QWindowsIntegrationPrivate::QWindowsIntegrationPrivate(const QStringList &paramList)
     : m_options(parseOptions(paramList))
     , m_fontDatabase(0)
-    , m_eventDispatcher(new QWindowsGuiEventDispatcher)
 {
 }
 
@@ -369,7 +367,6 @@ QWindowsIntegrationPrivate::~QWindowsIntegrationPrivate()
 QWindowsIntegration::QWindowsIntegration(const QStringList &paramList) :
     d(new QWindowsIntegrationPrivate(paramList))
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(d->m_eventDispatcher);
 #ifndef QT_NO_CLIPBOARD
     d->m_clipboard.registerViewer();
 #endif
@@ -635,9 +632,9 @@ QPlatformSessionManager *QWindowsIntegration::createPlatformSessionManager(const
 }
 #endif
 
-QAbstractEventDispatcher * QWindowsIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher * QWindowsIntegration::createEventDispatcher() const
 {
-    return d->m_eventDispatcher;
+    return new QWindowsGuiEventDispatcher;
 }
 
 QStringList QWindowsIntegration::themeNames() const

src/plugins/platforms/windows/qwindowsintegration.h

@@ -74,7 +74,7 @@ public:
 #ifndef QT_NO_OPENGL
     virtual QPlatformOpenGLContext *createPlatformOpenGLContext(QOpenGLContext *context) const;
 #endif
-    virtual QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    virtual QAbstractEventDispatcher *createEventDispatcher() const;
 #ifndef QT_NO_CLIPBOARD
     virtual QPlatformClipboard *clipboard() const;
 #  ifndef QT_NO_DRAGANDDROP

src/plugins/platforms/xcb/qxcbintegration.cpp

@@ -124,12 +124,9 @@ static bool runningUnderDebugger()
 #endif
 
 QXcbIntegration::QXcbIntegration(const QStringList &parameters, int &argc, char **argv)
-    : m_eventDispatcher(createUnixEventDispatcher())
-    ,  m_services(new QGenericUnixServices)
+    : m_services(new QGenericUnixServices)
     , m_instanceName(0)
 {
-    QGuiApplicationPrivate::instance()->setEventDispatcher(m_eventDispatcher);
-
 #ifdef XCB_USE_XLIB
     XInitThreads();
 #endif
@@ -293,9 +290,9 @@ bool QXcbIntegration::hasCapability(QPlatformIntegration::Capability cap) const
     }
 }
 
-QAbstractEventDispatcher *QXcbIntegration::guiThreadEventDispatcher() const
+QAbstractEventDispatcher *QXcbIntegration::createEventDispatcher() const
 {
-    return m_eventDispatcher;
+    return createUnixEventDispatcher();
 }
 
 void QXcbIntegration::moveToScreen(QWindow *window, int screen)

src/plugins/platforms/xcb/qxcbintegration.h

@@ -67,7 +67,7 @@ public:
     QPlatformOffscreenSurface *createPlatformOffscreenSurface(QOffscreenSurface *surface) const;
 
     bool hasCapability(Capability cap) const;
-    QAbstractEventDispatcher *guiThreadEventDispatcher() const;
+    QAbstractEventDispatcher *createEventDispatcher() const;
 
     void moveToScreen(QWindow *window, int screen);
 
@@ -112,7 +112,6 @@ private:
     QScopedPointer<QXcbNativeInterface> m_nativeInterface;
 
     QScopedPointer<QPlatformInputContext> m_inputContext;
-    QAbstractEventDispatcher *m_eventDispatcher;
 
 #ifndef QT_NO_ACCESSIBILITY
     QScopedPointer<QPlatformAccessibility> m_accessibility;