client: Guard against client destruction in gestures

Client code can delete a window at any point. Any gesture events,
including a "begin" event can be already in flight before the compositor
is aware of the window destruction.

It's up to the client code to handle either the focus not being
initially found or the QPointer resetting and no-op.

Task-number: QTBUG-113145
Change-Id: Ie2c01799bd38c6f295159876a1bcd018abe60188
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
(cherry picked from commit 5587deee20f5c12f7a9ae242758b108c1a85d7dd)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 20 insertions, 3 deletions

diff --git a/src/client/qwaylandpointergestures.cpp b/src/client/qwaylandpointergestures.cpp
index df43c31e9..1cdd97edd 100644
--- a/src/client/qwaylandpointergestures.cpp
+++ b/src/client/qwaylandpointergestures.cpp
@@ -41,8 +41,11 @@ void QWaylandPointerGestureSwipe::zwp_pointer_gesture_swipe_v1_begin(uint32_t se
                                                                      uint32_t fingers)
 {
 #ifndef QT_NO_GESTURES
-    mParent->mSerial = serial;
     mFocus = QWaylandWindow::fromWlSurface(surface);
+    if (!mFocus) {
+        return;
+    }
+    mParent->mSerial = serial;
     mFingers = fingers;
 
     const auto* pointer = mParent->pointer();
@@ -62,6 +65,9 @@ void QWaylandPointerGestureSwipe::zwp_pointer_gesture_swipe_v1_update(uint32_t t
                                                                       wl_fixed_t dx, wl_fixed_t dy)
 {
 #ifndef QT_NO_GESTURES
+    if (!mFocus) {
+        return;
+    }
     const auto* pointer = mParent->pointer();
 
     const QPointF delta = QPointF(wl_fixed_to_double(dx), wl_fixed_to_double(dy));
@@ -79,6 +85,9 @@ void QWaylandPointerGestureSwipe::zwp_pointer_gesture_swipe_v1_end(uint32_t seri
                                                                    int32_t cancelled)
 {
 #ifndef QT_NO_GESTURES
+    if (!mFocus) {
+        return;
+    }
     mParent->mSerial = serial;
     const auto* pointer = mParent->pointer();
 
@@ -113,11 +122,13 @@ void QWaylandPointerGesturePinch::zwp_pointer_gesture_pinch_v1_begin(uint32_t se
                                                                      uint32_t fingers)
 {
 #ifndef QT_NO_GESTURES
-    mParent->mSerial = serial;
     mFocus = QWaylandWindow::fromWlSurface(surface);
+    if (!mFocus) {
+        return;
+    }
+    mParent->mSerial = serial;
     mFingers = fingers;
     mLastScale = 1;
-
     const auto* pointer = mParent->pointer();
 
     qCDebug(lcQpaWaylandInput) << "zwp_pointer_gesture_pinch_v1_begin @ "
@@ -137,6 +148,9 @@ void QWaylandPointerGesturePinch::zwp_pointer_gesture_pinch_v1_update(uint32_t t
                                                                       wl_fixed_t rotation)
 {
 #ifndef QT_NO_GESTURES
+    if (!mFocus) {
+        return;
+    }
     const auto* pointer = mParent->pointer();
 
     const qreal rscale = wl_fixed_to_double(scale);
@@ -161,6 +175,9 @@ void QWaylandPointerGesturePinch::zwp_pointer_gesture_pinch_v1_end(uint32_t seri
                                                                    int32_t cancelled)
 {
 #ifndef QT_NO_GESTURES
+    if (!mFocus) {
+        return;
+    }
     mParent->mSerial = serial;
     const auto* pointer = mParent->pointer();