Add a virtual sendPostedEvents() to QEventDispatcherWin32.

Reimplement this in QWindowGuiEventDispatcher to send both Qt posted events and
queued QPA window system events. We need to do this at a well defined place,
instead of sending events outside of the eventloop from the Windows proc.

This fixes various hangs for example in tst_qinputdialog, which used a 0-timer
to close a dialog.

Change-Id: I64e0b8f1209fb434059a7fa667ed585902c19db4
Initial-patch-by: bhughes <bradley.hughes@nokia.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>

3 files changed, 10 insertions, 9 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.cpp b/src/plugins/platforms/windows/qwindowscontext.cpp
index 5e101d1869..4f42f7fa3b 100644
--- a/src/plugins/platforms/windows/qwindowscontext.cpp
+++ b/src/plugins/platforms/windows/qwindowscontext.cpp
@@ -747,18 +747,11 @@ extern "C" LRESULT QT_WIN_CALLBACK qWindowsWndProc(HWND hwnd, UINT message, WPAR
     LRESULT result;
     const QtWindows::WindowsEventType et = windowsEventType(message, wParam);
     const bool handled = QWindowsContext::instance()->windowsProc(hwnd, message, et, wParam, lParam, &result);
-    const bool guiEventsQueued = QWindowSystemInterface::windowSystemEventsQueued();
     if (QWindowsContext::verboseEvents > 1)
         if (const char *eventName = QWindowsGuiEventDispatcher::windowsMessageName(message))
-            qDebug("EVENT: hwd=%p %s msg=0x%x et=0x%x wp=%d at %d,%d handled=%d gui=%d",
+            qDebug("EVENT: hwd=%p %s msg=0x%x et=0x%x wp=%d at %d,%d handled=%d",
                    hwnd, eventName, message, et, int(wParam),
-                   GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam), handled, guiEventsQueued);
-    if (guiEventsQueued) {
-        const QWindowsGuiEventDispatcher::DispatchContext dispatchContext =
-            QWindowsGuiEventDispatcher::currentDispatchContext();
-        if (dispatchContext.first)
-            QWindowSystemInterface::sendWindowSystemEvents(dispatchContext.first, dispatchContext.second);
-    }
+                   GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam), handled);
     if (!handled)
         result = DefWindowProc(hwnd, message, wParam, lParam);
     return result;
diff --git a/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp b/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp
index cd5d28317e..4dd409a2ab 100644
--- a/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp
+++ b/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp
@@ -97,6 +97,13 @@ bool QWindowsGuiEventDispatcher::processEvents(QEventLoop::ProcessEventsFlags fl
     return rc;
 }
 
+void QWindowsGuiEventDispatcher::sendPostedEvents()
+{
+    QWindowsGuiEventDispatcher::DispatchContext context = currentDispatchContext();
+    Q_ASSERT(context.first != 0);
+    QWindowSystemInterface::sendWindowSystemEvents(context.first, context.second);
+}
+
 QWindowsGuiEventDispatcher::DispatchContext QWindowsGuiEventDispatcher::currentDispatchContext()
 {
     const DispatchContextStack &stack = *dispatchContextStack();
diff --git a/src/plugins/platforms/windows/qwindowsguieventdispatcher.h b/src/plugins/platforms/windows/qwindowsguieventdispatcher.h
index 8d2bc1997b..87a0c915ce 100644
--- a/src/plugins/platforms/windows/qwindowsguieventdispatcher.h
+++ b/src/plugins/platforms/windows/qwindowsguieventdispatcher.h
@@ -64,6 +64,7 @@ public:
     static const char *windowsMessageName(UINT msg);
 
     virtual bool QT_ENSURE_STACK_ALIGNED_FOR_SSE processEvents(QEventLoop::ProcessEventsFlags flags);
+    virtual void sendPostedEvents();
 };
 
 QT_END_NAMESPACE