diff options
| -rw-r--r-- | src/plugins/platforms/xcb/qxcbclipboard.cpp | 8 | ||||
| -rw-r--r-- | src/plugins/platforms/xcb/qxcbeventqueue.cpp | 8 | ||||
| -rw-r--r-- | src/plugins/platforms/xcb/qxcbeventqueue.h | 4 |
3 files changed, 15 insertions, 5 deletions
diff --git a/src/plugins/platforms/xcb/qxcbclipboard.cpp b/src/plugins/platforms/xcb/qxcbclipboard.cpp index ac8b029916..725c0e4d51 100644 --- a/src/plugins/platforms/xcb/qxcbclipboard.cpp +++ b/src/plugins/platforms/xcb/qxcbclipboard.cpp @@ -787,6 +787,12 @@ xcb_generic_event_t *QXcbClipboard::waitForClipboardEvent(xcb_window_t window, i if (e) // found the waited for event return e; + // It is safe to assume here that the pointed to node won't be re-used + // while we are holding the pointer to it. The nodes can be recycled + // only when they are dequeued, which is done only by + // QXcbConnection::processXcbEvents(). + const QXcbEventNode *flushedTailNode = queue->flushedTail(); + if (checkManager) { auto reply = Q_XCB_REPLY(xcb_get_selection_owner, xcb_connection(), atom(QXcbAtom::CLIPBOARD_MANAGER)); if (!reply || reply->owner == XCB_NONE) @@ -812,7 +818,7 @@ xcb_generic_event_t *QXcbClipboard::waitForClipboardEvent(xcb_window_t window, i const auto elapsed = timer.elapsed(); if (elapsed < clipboard_timeout) - queue->waitForNewEvents(clipboard_timeout - elapsed); + queue->waitForNewEvents(flushedTailNode, clipboard_timeout - elapsed); } while (timer.elapsed() < clipboard_timeout); return nullptr; diff --git a/src/plugins/platforms/xcb/qxcbeventqueue.cpp b/src/plugins/platforms/xcb/qxcbeventqueue.cpp index 4ca73e3048..b96bda3194 100644 --- a/src/plugins/platforms/xcb/qxcbeventqueue.cpp +++ b/src/plugins/platforms/xcb/qxcbeventqueue.cpp @@ -226,6 +226,8 @@ void QXcbEventQueue::run() }; while (!m_closeConnectionDetected && (event = xcb_wait_for_event(connection))) { + // This lock can block only if there are users of waitForNewEvents(). + // Currently only the clipboard implementation relies on it. m_newEventsMutex.lock(); enqueueEvent(event); while (!m_closeConnectionDetected && (event = xcb_poll_for_queued_event(connection))) @@ -350,12 +352,12 @@ bool QXcbEventQueue::peekEventQueue(PeekerCallback peeker, void *peekerData, return result; } -void QXcbEventQueue::waitForNewEvents(unsigned long time) +void QXcbEventQueue::waitForNewEvents(const QXcbEventNode *sinceFlushedTail, + unsigned long time) { QMutexLocker locker(&m_newEventsMutex); - QXcbEventNode *tailBeforeFlush = m_flushedTail; flushBufferedEvents(); - if (tailBeforeFlush != m_flushedTail) + if (sinceFlushedTail != m_flushedTail) return; m_newEventsCondition.wait(&m_newEventsMutex, time); } diff --git a/src/plugins/platforms/xcb/qxcbeventqueue.h b/src/plugins/platforms/xcb/qxcbeventqueue.h index 11d0b8e963..c8f09ed9e3 100644 --- a/src/plugins/platforms/xcb/qxcbeventqueue.h +++ b/src/plugins/platforms/xcb/qxcbeventqueue.h @@ -106,7 +106,9 @@ public: bool peekEventQueue(PeekerCallback peeker, void *peekerData = nullptr, PeekOptions option = PeekDefault, qint32 peekerId = -1); - void waitForNewEvents(unsigned long time = ULONG_MAX); + const QXcbEventNode *flushedTail() const { return m_flushedTail; } + void waitForNewEvents(const QXcbEventNode *sinceFlushedTail, + unsigned long time = ULONG_MAX); private: QXcbEventNode *qXcbEventNodeFactory(xcb_generic_event_t *event); |