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client: Simplify round trip behavior

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The custom event queue was removed in
d49cd790d8525071f6613066caf5e8dd2f5ca980 (2015) so the comment about not
being able to use the inbuilt round trip method no longer applies.

This fixes a real world problem. Use of a blocking round trip should not
process non wayland events. Doing so can lead to misbehaviour client
side as things happen out of order. The move to the event thread created
several regressions as we now get events before the QGuiApplication is
fully constructed.

Change-Id: I650481f49a47ed1a9778c7e1bc3c48db6e8f0031
Reviewed-by: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
This commit is contained in:
David Edmundson 2022-02-09 17:20:48 +00:00
parent 651d6dcfe3
commit 610e084250
1 changed files with 1 additions and 42 deletions
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43
src/plugins/platforms/wayland/qwaylanddisplay.cpp
View File

@ -728,50 +728,9 @@ uint32_t QWaylandDisplay::currentTimeMillisec()
return 0;
}
static void
sync_callback(void *data, struct wl_callback *callback, uint32_t serial)
{
Q_UNUSED(serial);
bool *done = static_cast<bool *>(data);
*done = true;
// If the wl_callback done event is received after the condition check in the while loop in
// forceRoundTrip(), but before the call to processEvents, the call to processEvents may block
// forever if no more events are posted (eventhough the callback is handled in response to the
// aboutToBlock signal). Hence, we wake up the event dispatcher so forceRoundTrip may return.
// (QTBUG-64696)
if (auto *dispatcher = QThread::currentThread()->eventDispatcher())
dispatcher->wakeUp();
wl_callback_destroy(callback);
}
static const struct wl_callback_listener sync_listener = {
sync_callback
};
void QWaylandDisplay::forceRoundTrip()
{
// wl_display_roundtrip() works on the main queue only,
// but we use a separate one, so basically reimplement it here
int ret = 0;
bool done = false;
wl_callback *callback = wl_display_sync(mDisplay);
wl_callback_add_listener(callback, &sync_listener, &done);
flushRequests();
if (QThread::currentThread()->eventDispatcher()) {
while (!done && ret >= 0) {
QThread::currentThread()->eventDispatcher()->processEvents(QEventLoop::WaitForMoreEvents);
ret = wl_display_dispatch_pending(mDisplay);
}
} else {
while (!done && ret >= 0)
ret = wl_display_dispatch(mDisplay);
}
if (ret == -1 && !done)
wl_callback_destroy(callback);
wl_display_roundtrip(mDisplay);
}
bool QWaylandDisplay::supportsWindowDecoration() const