QPA: Flush window system events with flags.

Add a QEventLoop::ProcessEventsFlags argument to
flushWindowSystemEvents(). This gives the platform
plugins more control over which events to flush.

Task-number: QTBUG-39842
Change-Id: Id9c01948b22e297b22503d38ec4e726f9f880fd5
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Jonathan Liu <net147@gmail.com>

4 files changed, 13 insertions, 10 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 5233d76d7b..59bcd37251 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -1628,8 +1628,9 @@ void QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePriv
         QWindowSystemInterfacePrivate::ApplicationStateChangedEvent * changeEvent = static_cast<QWindowSystemInterfacePrivate::ApplicationStateChangedEvent *>(e);
         QGuiApplicationPrivate::setApplicationState(changeEvent->newState, changeEvent->forcePropagate); }
         break;
-    case QWindowSystemInterfacePrivate::FlushEvents:
-        QWindowSystemInterface::deferredFlushWindowSystemEvents();
+    case QWindowSystemInterfacePrivate::FlushEvents: {
+        QWindowSystemInterfacePrivate::FlushEventsEvent *flushEventsEvent = static_cast<QWindowSystemInterfacePrivate::FlushEventsEvent *>(e);
+        QWindowSystemInterface::deferredFlushWindowSystemEvents(flushEventsEvent->flags); }
         break;
     case QWindowSystemInterfacePrivate::Close:
         QGuiApplicationPrivate::processCloseEvent(
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index bd95a8614f..722a695481 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -526,16 +526,16 @@ void QWindowSystemInterface::handleExposeEvent(QWindow *tlw, const QRegion &regi
     QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
 }
 
-void QWindowSystemInterface::deferredFlushWindowSystemEvents()
+void QWindowSystemInterface::deferredFlushWindowSystemEvents(QEventLoop::ProcessEventsFlags flags)
 {
     Q_ASSERT(QThread::currentThread() == QGuiApplication::instance()->thread());
 
     QMutexLocker locker(&QWindowSystemInterfacePrivate::flushEventMutex);
-    flushWindowSystemEvents();
+    flushWindowSystemEvents(flags);
     QWindowSystemInterfacePrivate::eventsFlushed.wakeOne();
 }
 
-void QWindowSystemInterface::flushWindowSystemEvents()
+void QWindowSystemInterface::flushWindowSystemEvents(QEventLoop::ProcessEventsFlags flags)
 {
     const int count = QWindowSystemInterfacePrivate::windowSystemEventQueue.count();
     if (!count)
@@ -549,11 +549,11 @@ void QWindowSystemInterface::flushWindowSystemEvents()
     }
     if (QThread::currentThread() != QGuiApplication::instance()->thread()) {
         QMutexLocker locker(&QWindowSystemInterfacePrivate::flushEventMutex);
-        QWindowSystemInterfacePrivate::FlushEventsEvent *e = new QWindowSystemInterfacePrivate::FlushEventsEvent();
+        QWindowSystemInterfacePrivate::FlushEventsEvent *e = new QWindowSystemInterfacePrivate::FlushEventsEvent(flags);
         QWindowSystemInterfacePrivate::handleWindowSystemEvent(e);
         QWindowSystemInterfacePrivate::eventsFlushed.wait(&QWindowSystemInterfacePrivate::flushEventMutex);
     } else {
-        sendWindowSystemEvents(QEventLoop::AllEvents);
+        sendWindowSystemEvents(flags);
     }
 }
 
diff --git a/src/gui/kernel/qwindowsysteminterface.h b/src/gui/kernel/qwindowsysteminterface.h
index 9784757d3a..30c236b51f 100644
--- a/src/gui/kernel/qwindowsysteminterface.h
+++ b/src/gui/kernel/qwindowsysteminterface.h
@@ -208,8 +208,8 @@ public:
     // For event dispatcher implementations
     static bool sendWindowSystemEvents(QEventLoop::ProcessEventsFlags flags);
     static void setSynchronousWindowsSystemEvents(bool enable);
-    static void flushWindowSystemEvents();
-    static void deferredFlushWindowSystemEvents();
+    static void flushWindowSystemEvents(QEventLoop::ProcessEventsFlags flags = QEventLoop::AllEvents);
+    static void deferredFlushWindowSystemEvents(QEventLoop::ProcessEventsFlags flags);
     static int windowSystemEventsQueued();
 };
 
diff --git a/src/gui/kernel/qwindowsysteminterface_p.h b/src/gui/kernel/qwindowsysteminterface_p.h
index f48c75a027..c3f41da835 100644
--- a/src/gui/kernel/qwindowsysteminterface_p.h
+++ b/src/gui/kernel/qwindowsysteminterface_p.h
@@ -178,9 +178,11 @@ public:
 
     class FlushEventsEvent : public WindowSystemEvent {
     public:
-        FlushEventsEvent()
+        FlushEventsEvent(QEventLoop::ProcessEventsFlags f = QEventLoop::AllEvents)
             : WindowSystemEvent(FlushEvents)
+            , flags(f)
         { }
+        QEventLoop::ProcessEventsFlags flags;
     };
 
     class UserEvent : public WindowSystemEvent {