Ensure sendPostedEvents() can be called independently

If Qt is not running its own event loop (e.g. if Qt is a plugin running
in a non-Qt host application with its own event loop, a call to
sendPostedEvents() should process all events by default, and not depend
on the flags passed to the last call to processEvents()

We also modify sendPostedEvents() to call its base implementation instead
of directly calling QCoreApplication::sendPostedEvents(). (The behavior of
the base implementation is the same, so no behavior change there).

This also adds a test for QWindow event handling without Qts event loop is
running. This is a black box test, just to ensure that basic functionality
is working. It can be extended later.

Task-number: QTBUG-45956
Change-Id: I7d688c0c6dec5f133fb495f07526debdde5389af
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp b/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp
index 0dd2facd4d..0bfa0239aa 100644
--- a/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp
+++ b/src/plugins/platforms/windows/qwindowsguieventdispatcher.cpp
@@ -67,18 +67,20 @@ QWindowsGuiEventDispatcher::QWindowsGuiEventDispatcher(QObject *parent) :
 
 bool QWindowsGuiEventDispatcher::processEvents(QEventLoop::ProcessEventsFlags flags)
 {
+    const QEventLoop::ProcessEventsFlags oldFlags = m_flags;
     m_flags = flags;
     if (QWindowsContext::verbose > 2 && lcQpaEvents().isDebugEnabled())
         qCDebug(lcQpaEvents) << '>' << __FUNCTION__ << objectName() << flags;
     const bool rc = QEventDispatcherWin32::processEvents(flags);
     if (QWindowsContext::verbose > 2 && lcQpaEvents().isDebugEnabled())
         qCDebug(lcQpaEvents) << '<' << __FUNCTION__ << "returns" << rc;
+    m_flags = oldFlags;
     return rc;
 }
 
 void QWindowsGuiEventDispatcher::sendPostedEvents()
 {
-    QCoreApplication::sendPostedEvents();
+    QEventDispatcherWin32::sendPostedEvents();
     QWindowSystemInterface::sendWindowSystemEvents(m_flags);
 }