Fix crash after destroying view with mouse focus

Don't emit QWaylandSeat::mouseFocusChanged with a destroyed QWaylandView.

QWaylandPointer has been refactored to make it easier to follow enter and
leave logic. A missing emit for buttonPressedChanged has been fixed as well.

This also adds a test for pointer events to verify that setting mouse focus
works and that the crash has been fixed.

Task-number: QTBUG-63208
Change-Id: Id0c174a7b609dfd0152f3ae446dd51fd8befd554
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/compositor/compositor_api/qwaylandseat.cpp b/src/compositor/compositor_api/qwaylandseat.cpp
index 80b75d617..b4b45392c 100644
--- a/src/compositor/compositor_api/qwaylandseat.cpp
+++ b/src/compositor/compositor_api/qwaylandseat.cpp
@@ -456,6 +456,12 @@ void QWaylandSeat::setMouseFocus(QWaylandView *view)
 
     QWaylandView *oldFocus = d->mouseFocus;
     d->mouseFocus = view;
+
+    if (oldFocus)
+        disconnect(oldFocus, &QObject::destroyed, this, &QWaylandSeat::handleMouseFocusDestroyed);
+    if (d->mouseFocus)
+        connect(d->mouseFocus, &QObject::destroyed, this, &QWaylandSeat::handleMouseFocusDestroyed);
+
     emit mouseFocusChanged(d->mouseFocus, oldFocus);
 }
 
@@ -512,4 +518,15 @@ QWaylandSeat *QWaylandSeat::fromSeatResource(struct ::wl_resource *resource)
  * This signal is emitted when the mouse focus has changed from \a oldFocus to \a newFocus.
  */
 
+void QWaylandSeat::handleMouseFocusDestroyed()
+{
+    // This is triggered when the QWaylandView is destroyed, NOT the surface.
+    // ... so this is for the rare case when the view that currently holds the mouse focus is
+    // destroyed before its surface
+    Q_D(QWaylandSeat);
+    d->mouseFocus = nullptr;
+    QWaylandView *oldFocus = nullptr; // we have to send nullptr because the old focus is already destroyed at this point
+    emit mouseFocusChanged(d->mouseFocus, oldFocus);
+}
+
 QT_END_NAMESPACE