iOS: Take advantage of new synchronous API for QPA event delivery

By using the SynchronousDelivery specialization instead of flushing all
window system events, we remove the risk of flushing an event that was
added without our knowledge.

For example, QGuiApplicationPrivate::processMouseEvent() used to prepend
a mouse move event to the QPA queue, which is why we had a check for
QWidgetWindow when flushing geometry changes. processMouseEvent no longer
sends the move event via the QPA queue, so that's no longer an issue,
but if it were to be reintroduced, we wouldn't need to check for
QWidgetWindow, as we're not flushing all events anymore.

Change-Id: Ib346ea9501cd88ddda6c2137981d3eb0922192a0
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

src/gui/kernel/qwindowsysteminterface.cpp

@@ -165,11 +165,11 @@ void QWindowSystemInterface::handleEnterLeaveEvent(QWindow *enter, QWindow *leav
     handleEnterEvent(enter, local, global);
 }
 
-void QWindowSystemInterface::handleWindowActivated(QWindow *tlw, Qt::FocusReason r)
+QT_DEFINE_QPA_EVENT_HANDLER(void, handleWindowActivated, QWindow *tlw, Qt::FocusReason r)
 {
     QWindowSystemInterfacePrivate::ActivatedWindowEvent *e =
         new QWindowSystemInterfacePrivate::ActivatedWindowEvent(tlw, r);
-    QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
+    QWindowSystemInterfacePrivate::handleWindowSystemEvent<Delivery>(e);
 }
 
 void QWindowSystemInterface::handleWindowStateChanged(QWindow *tlw, Qt::WindowState newState)
@@ -197,10 +197,25 @@ void QWindowSystemInterface::handleApplicationStateChanged(Qt::ApplicationState
 /*!
   If \a oldRect is null, Qt will use the previously reported geometry instead.
  */
-void QWindowSystemInterface::handleGeometryChange(QWindow *tlw, const QRect &newRect, const QRect &oldRect)
+QT_DEFINE_QPA_EVENT_HANDLER(void, handleGeometryChange, QWindow *tlw, const QRect &newRect, const QRect &oldRect)
 {
     QWindowSystemInterfacePrivate::GeometryChangeEvent *e = new QWindowSystemInterfacePrivate::GeometryChangeEvent(tlw, QHighDpi::fromNativePixels(newRect, tlw), QHighDpi::fromNativePixels(oldRect, tlw));
-    QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
+    QWindowSystemInterfacePrivate::handleWindowSystemEvent<Delivery>(e);
+}
+
+QWindowSystemInterfacePrivate::ExposeEvent::ExposeEvent(QWindow *window, const QRegion &region)
+    : WindowSystemEvent(Expose)
+    , window(window)
+    , isExposed(window && window->handle() ? window->handle()->isExposed() : false)
+    , region(region)
+{
+}
+
+QT_DEFINE_QPA_EVENT_HANDLER(void, handleExposeEvent, QWindow *tlw, const QRegion &region)
+{
+    QWindowSystemInterfacePrivate::ExposeEvent *e =
+        new QWindowSystemInterfacePrivate::ExposeEvent(tlw, QHighDpi::fromNativeLocalExposedRegion(region, tlw));
+    QWindowSystemInterfacePrivate::handleWindowSystemEvent<Delivery>(e);
 }
 
 void QWindowSystemInterface::handleCloseEvent(QWindow *tlw, bool *accepted)
@@ -405,15 +420,6 @@ void QWindowSystemInterface::handleWheelEvent(QWindow *tlw, ulong timestamp, con
     QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
 }
 
-
-QWindowSystemInterfacePrivate::ExposeEvent::ExposeEvent(QWindow *window, const QRegion &region)
-    : WindowSystemEvent(Expose)
-    , window(window)
-    , isExposed(window && window->handle() ? window->handle()->isExposed() : false)
-    , region(region)
-{
-}
-
 int QWindowSystemInterfacePrivate::windowSystemEventsQueued()
 {
     return windowSystemEventQueue.count();
@@ -596,20 +602,20 @@ QT_DEFINE_QPA_EVENT_HANDLER(void, handleTouchEvent, QWindow *tlw, ulong timestam
     QWindowSystemInterfacePrivate::handleWindowSystemEvent<Delivery>(e);
 }
 
-void QWindowSystemInterface::handleTouchCancelEvent(QWindow *w, QTouchDevice *device,
+QT_DEFINE_QPA_EVENT_HANDLER(void, handleTouchCancelEvent, QWindow *w, QTouchDevice *device,
                                                     Qt::KeyboardModifiers mods)
 {
     unsigned long time = QWindowSystemInterfacePrivate::eventTime.elapsed();
-    handleTouchCancelEvent(w, time, device, mods);
+    handleTouchCancelEvent<Delivery>(w, time, device, mods);
 }
 
-void QWindowSystemInterface::handleTouchCancelEvent(QWindow *w, ulong timestamp, QTouchDevice *device,
+QT_DEFINE_QPA_EVENT_HANDLER(void, handleTouchCancelEvent, QWindow *w, ulong timestamp, QTouchDevice *device,
                                                     Qt::KeyboardModifiers mods)
 {
     QWindowSystemInterfacePrivate::TouchEvent *e =
             new QWindowSystemInterfacePrivate::TouchEvent(w, timestamp, QEvent::TouchCancel, device,
                                                          QList<QTouchEvent::TouchPoint>(), mods);
-    QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
+    QWindowSystemInterfacePrivate::handleWindowSystemEvent<Delivery>(e);
 }
 
 void QWindowSystemInterface::handleScreenOrientationChange(QScreen *screen, Qt::ScreenOrientation orientation)
@@ -646,13 +652,6 @@ void QWindowSystemInterface::handleThemeChange(QWindow *tlw)
     QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
 }
 
-void QWindowSystemInterface::handleExposeEvent(QWindow *tlw, const QRegion &region)
-{
-    QWindowSystemInterfacePrivate::ExposeEvent *e =
-        new QWindowSystemInterfacePrivate::ExposeEvent(tlw, QHighDpi::fromNativeLocalExposedRegion(region, tlw));
-    QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
-}
-
 void QWindowSystemInterface::deferredFlushWindowSystemEvents(QEventLoop::ProcessEventsFlags flags)
 {
     Q_ASSERT(QThread::currentThread() == QGuiApplication::instance()->thread());

src/gui/kernel/qwindowsysteminterface.h

@@ -150,11 +150,19 @@ public:
     template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
     static void handleTouchEvent(QWindow *w, ulong timestamp, QTouchDevice *device,
                                  const QList<struct TouchPoint> &points, Qt::KeyboardModifiers mods = Qt::NoModifier);
+    template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
     static void handleTouchCancelEvent(QWindow *w, QTouchDevice *device, Qt::KeyboardModifiers mods = Qt::NoModifier);
+    template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
     static void handleTouchCancelEvent(QWindow *w, ulong timestamp, QTouchDevice *device, Qt::KeyboardModifiers mods = Qt::NoModifier);
 
     // rect is relative to parent
+    template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
     static void handleGeometryChange(QWindow *w, const QRect &newRect, const QRect &oldRect = QRect());
+
+    // region is in local coordinates, do not confuse with geometry which is parent-relative
+    template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
+    static void handleExposeEvent(QWindow *tlw, const QRegion &region);
+
     static void handleCloseEvent(QWindow *w, bool *accepted = Q_NULLPTR);
 
     template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
@@ -162,6 +170,7 @@ public:
     template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
     static void handleLeaveEvent(QWindow *w);
     static void handleEnterLeaveEvent(QWindow *enter, QWindow *leave, const QPointF &local = QPointF(), const QPointF& global = QPointF());
+    template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
     static void handleWindowActivated(QWindow *w, Qt::FocusReason r = Qt::OtherFocusReason);
 
     static void handleWindowStateChanged(QWindow *w, Qt::WindowState newState);
@@ -169,9 +178,6 @@ public:
 
     static void handleApplicationStateChanged(Qt::ApplicationState newState, bool forcePropagate = false);
 
-    // region is in local coordinates, do not confuse with geometry which is parent-relative
-    static void handleExposeEvent(QWindow *tlw, const QRegion &region);
-
 #ifndef QT_NO_DRAGANDDROP
     // Drag and drop. These events are sent immediately.
     static QPlatformDragQtResponse handleDrag(QWindow *w, const QMimeData *dropData, const QPoint &p, Qt::DropActions supportedActions);

src/plugins/platforms/ios/quiview.mm

@@ -164,8 +164,7 @@
             requestedGeometry : qt_window_private(m_qioswindow->window())->geometry;
 
     QWindow *window = m_qioswindow->window();
-    QWindowSystemInterface::handleGeometryChange(window, actualGeometry, previousGeometry);
+    QWindowSystemInterface::handleGeometryChange<QWindowSystemInterface::SynchronousDelivery>(window, actualGeometry, previousGeometry);
-    QWindowSystemInterface::flushWindowSystemEvents(window->inherits("QWidgetWindow") ? QEventLoop::ExcludeUserInputEvents : QEventLoop::AllEvents);
 
     if (actualGeometry.size() != previousGeometry.size()) {
         // Trigger expose event on resize
@@ -197,8 +196,7 @@
         region = QRect(QPoint(), bounds);
     }
 
-    QWindowSystemInterface::handleExposeEvent(m_qioswindow->window(), region);
+    QWindowSystemInterface::handleExposeEvent<QWindowSystemInterface::SynchronousDelivery>(m_qioswindow->window(), region);
-    QWindowSystemInterface::flushWindowSystemEvents();
 }
 
 // -------------------------------------------------------------------------
@@ -223,13 +221,10 @@
 
     qImDebug() << m_qioswindow->window() << "became first responder";
 
-    if (qGuiApp->focusWindow() != m_qioswindow->window()) {
+    if (qGuiApp->focusWindow() != m_qioswindow->window())
-        QWindowSystemInterface::handleWindowActivated(m_qioswindow->window());
+        QWindowSystemInterface::handleWindowActivated<QWindowSystemInterface::SynchronousDelivery>(m_qioswindow->window());
-        QWindowSystemInterface::flushWindowSystemEvents();
+    else
-    } else {
+        qImDebug() << m_qioswindow->window() << "already active, not sending window activation";
-        qImDebug() << m_qioswindow->window()
-            << "already active, not sending window activation";
-    }
 
     return YES;
 }
@@ -264,10 +259,8 @@
     qImDebug() << m_qioswindow->window() << "resigned first responder";
 
     UIResponder *newResponder = FirstResponderCandidate::currentCandidate();
-    if ([self responderShouldTriggerWindowDeactivation:newResponder]) {
+    if ([self responderShouldTriggerWindowDeactivation:newResponder])
-        QWindowSystemInterface::handleWindowActivated(0);
+        QWindowSystemInterface::handleWindowActivated<QWindowSystemInterface::SynchronousDelivery>(0);
-        QWindowSystemInterface::flushWindowSystemEvents();
-    }
 
     return YES;
 }
@@ -357,10 +350,8 @@
 
 - (void)sendTouchEventWithTimestamp:(ulong)timeStamp
 {
-    // Send touch event synchronously
     QIOSIntegration *iosIntegration = QIOSIntegration::instance();
-    QWindowSystemInterface::handleTouchEvent(m_qioswindow->window(), timeStamp, iosIntegration->touchDevice(), m_activeTouches.values());
+    QWindowSystemInterface::handleTouchEvent<QWindowSystemInterface::SynchronousDelivery>(m_qioswindow->window(), timeStamp, iosIntegration->touchDevice(), m_activeTouches.values());
-    QWindowSystemInterface::flushWindowSystemEvents();
 }
 
 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
@@ -438,10 +429,8 @@
 
     NSTimeInterval timestamp = event ? event.timestamp : [[NSProcessInfo processInfo] systemUptime];
 
-    // Send cancel touch event synchronously
     QIOSIntegration *iosIntegration = static_cast<QIOSIntegration *>(QGuiApplicationPrivate::platformIntegration());
-    QWindowSystemInterface::handleTouchCancelEvent(m_qioswindow->window(), ulong(timestamp * 1000), iosIntegration->touchDevice());
+    QWindowSystemInterface::handleTouchCancelEvent<QWindowSystemInterface::SynchronousDelivery>(m_qioswindow->window(), ulong(timestamp * 1000), iosIntegration->touchDevice());
-    QWindowSystemInterface::flushWindowSystemEvents();
 }
 
 - (int)mapPressTypeToKey:(UIPress*)press
@@ -464,14 +453,12 @@
     // When handling the event (for example, as a back button), both press and
     // release events must be handled accordingly.
 
-    QScopedValueRollback<bool> syncRollback(QWindowSystemInterfacePrivate::synchronousWindowSystemEvents, true);
-
     bool handled = false;
     for (UIPress* press in presses) {
         int key = [self mapPressTypeToKey:press];
         if (key == Qt::Key_unknown)
             continue;
-        if (QWindowSystemInterface::handleKeyEvent(m_qioswindow->window(), type, key, Qt::NoModifier))
+        if (QWindowSystemInterface::handleKeyEvent<QWindowSystemInterface::SynchronousDelivery>(m_qioswindow->window(), type, key, Qt::NoModifier))
             handled = true;
     }