From d671bab0e3fc61532bcfdb4ff3f7a468d2b14b6b Mon Sep 17 00:00:00 2001 From: Volker Hilsheimer Date: Mon, 20 Dec 2021 18:41:26 +0100 Subject: [PATCH] Win32: always allow the event loop to be woken up by posted events We set the wakeUps atomic to prevent multiple WM_QT_SENDPOSTEDEVENTS from being posted. However, this might happen right after the event processing thread cleared the atomic, but before it processed the previous WM_QT_SENDPOSTEDEVENTS message. In that case, we end up with a set atomic and an empty event queue, resulting in the event loop to block even though there are posted QEvents. To prevent that, always reset the atomic when we handle the WM_QT_SENDPOSTEDEVENTS message. In that case, we either call sendPostedEvents, or startPostedEventsTimer. The former already resets wakeUps; reset it in the latter as well. Fixes: QTBUG-99323 Pick-to: 6.2 6.3 5.15 Change-Id: I931c02be9c42b02e8ca20daba5059cd8185f0a37 Reviewed-by: Alex Trotsenko --- src/corelib/kernel/qeventdispatcher_win.cpp | 2 ++ .../corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp | 3 --- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/src/corelib/kernel/qeventdispatcher_win.cpp b/src/corelib/kernel/qeventdispatcher_win.cpp index 97e3cbdb04..c1e7ddfdf9 100644 --- a/src/corelib/kernel/qeventdispatcher_win.cpp +++ b/src/corelib/kernel/qeventdispatcher_win.cpp @@ -249,6 +249,8 @@ LRESULT QT_WIN_CALLBACK qt_internal_proc(HWND hwnd, UINT message, WPARAM wp, LPA void QEventDispatcherWin32Private::startPostedEventsTimer() { + // we received WM_QT_SENDPOSTEDEVENTS, so allow posting it again + wakeUps.storeRelaxed(0); if (sendPostedEventsTimerId == 0) { // Start a timer to deliver posted events when the message queue is emptied. sendPostedEventsTimerId = SetTimer(internalHwnd, SendPostedEventsTimerId, diff --git a/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp b/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp index aea1c7ec9b..a3732f2d95 100644 --- a/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp +++ b/tests/auto/corelib/kernel/qeventdispatcher/tst_qeventdispatcher.cpp @@ -397,9 +397,6 @@ void tst_QEventDispatcher::postEventFromThread() } done = true; - if (QAbstractEventDispatcher::instance()->inherits("QEventDispatcherWin32")) - QEXPECT_FAIL("", QAbstractEventDispatcher::instance()->metaObject()->className(), Continue); - QVERIFY(!hadToQuit); QVERIFY(threadPool->waitForDone()); }