diff options
author | Volker Hilsheimer <volker.hilsheimer@qt.io> | 2019-10-08 10:56:44 +0200 |
---|---|---|
committer | Shawn Rutledge <shawn.rutledge@qt.io> | 2019-10-10 11:02:34 +0000 |
commit | 3dbc7596a3b7aca37e80f76288d3ab761ddd247a (patch) | |
tree | ef4edb907a016d7197dc538164dcc94a340b2aa7 /src | |
parent | 9845c06d1f8c3b30697cdf96b569849ee2372f47 (diff) |
Drag'n'Drop: fix crash when widgets are destroyed during event handling
Widgets might be destroyed when handling a dragMoveEvent, in which case
the following code will operate on dangling pointers or null pointers.
Use a QPointer to watch for the original event receiver to disappear,
and add the necessary checks for the objects we deliver events to being
null.
Change-Id: I4ca2f182540ae21113f4bea4e5c569e983cc58bf
Fixes: QTBUG-78907
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>
Diffstat (limited to 'src')
-rw-r--r-- | src/widgets/kernel/qwidgetwindow.cpp | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp index fbc71cd0ea..aad505ed29 100644 --- a/src/widgets/kernel/qwidgetwindow.cpp +++ b/src/widgets/kernel/qwidgetwindow.cpp @@ -885,7 +885,7 @@ void QWidgetWindow::handleDragEnterEvent(QDragEnterEvent *event, QWidget *widget void QWidgetWindow::handleDragMoveEvent(QDragMoveEvent *event) { - auto *widget = findDnDTarget(m_widget, event->pos()); + QPointer<QWidget> widget = findDnDTarget(m_widget, event->pos()); if (!widget) { event->ignore(); if (m_dragTarget) { // Send DragLeave to previous @@ -908,14 +908,18 @@ void QWidgetWindow::handleDragMoveEvent(QDragMoveEvent *event) QGuiApplication::forwardEvent(m_dragTarget, &leaveEvent, event); m_dragTarget = nullptr; } - // Send DragEnter to new widget. - handleDragEnterEvent(static_cast<QDragEnterEvent*>(event), widget); - // Handling 'DragEnter' should suffice for the application. - translated.setDropAction(event->dropAction()); - translated.setAccepted(event->isAccepted()); - // The drag enter event is always immediately followed by a drag move event, - // see QDragEnterEvent documentation. - QGuiApplication::forwardEvent(m_dragTarget, &translated, event); + // widget might have been deleted when handling the leaveEvent + if (widget) { + // Send DragEnter to new widget. + handleDragEnterEvent(static_cast<QDragEnterEvent*>(event), widget); + // Handling 'DragEnter' should suffice for the application. + translated.setDropAction(event->dropAction()); + translated.setAccepted(event->isAccepted()); + // The drag enter event is always immediately followed by a drag move event, + // see QDragEnterEvent documentation. + if (m_dragTarget) + QGuiApplication::forwardEvent(m_dragTarget, &translated, event); + } } event->setAccepted(translated.isAccepted()); event->setDropAction(translated.dropAction()); |