Fixes a crash when unregistering a recognizer.

Another fix for the same problem - we also need to be careful - when ungrabbing
a gesture for the recognizer that has already been destroyed and cleaning up
the QGesture object for it we need to make sure we know it is removed from the
obsolete gestures list so that we won't delete it again in the QGestureManager
detructor.

Task-number: QTBUG-9801
Reviewed-by: Thomas Zander

4 files changed, 23 insertions, 5 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 326f130..7fcf4d2 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -1423,6 +1423,13 @@ QGraphicsItem::~QGraphicsItem()
     d_ptr->inDestructor = 1;
     d_ptr->removeExtraItemCache();
 
+    if (d_ptr->isObject && !d_ptr->gestureContext.isEmpty()) {
+        QGraphicsObject *o = static_cast<QGraphicsObject *>(this);
+        QGestureManager *manager = QGestureManager::instance();
+        foreach (Qt::GestureType type, d_ptr->gestureContext.keys())
+            manager->cleanupCachedGestures(o, type);
+    }
+
     clearFocus();
 
     // Update focus scope item ptr.
diff --git a/src/gui/kernel/qgesturemanager.cpp b/src/gui/kernel/qgesturemanager.cpp
index a806629..6ce7667 100644
--- a/src/gui/kernel/qgesturemanager.cpp
+++ b/src/gui/kernel/qgesturemanager.cpp
@@ -140,9 +140,10 @@ void QGestureManager::unregisterGestureRecognizer(Qt::GestureType type)
         ObjectGesture objectGesture = iter.key();
         if (objectGesture.gesture == type) {
             foreach (QGesture *g, iter.value()) {
-                QGestureRecognizer *recognizer = m_gestureToRecognizer.value(g);
-                m_gestureToRecognizer.remove(g);
-                m_obsoleteGestures[recognizer].append(g);
+                if (QGestureRecognizer *recognizer = m_gestureToRecognizer.value(g)) {
+                    m_gestureToRecognizer.remove(g);
+                    m_obsoleteGestures[recognizer].insert(g);
+                }
             }
         }
         ++iter;
@@ -155,7 +156,14 @@ void QGestureManager::cleanupCachedGestures(QObject *target, Qt::GestureType typ
     while (iter != m_objectGestures.end()) {
         ObjectGesture objectGesture = iter.key();
         if (objectGesture.gesture == type && target == objectGesture.object.data()) {
-            qDeleteAll(iter.value());
+            QSet<QGesture *> gestures = iter.value().toSet();
+            for (QHash<QGestureRecognizer *, QSet<QGesture *> >::iterator
+                 it = m_obsoleteGestures.begin(), e = m_obsoleteGestures.end(); it != e; ++it) {
+                it.value() -= gestures;
+            }
+            foreach (QGesture *g, gestures)
+                m_deletedRecognizers.remove(g);
+            qDeleteAll(gestures);
             iter = m_objectGestures.erase(iter);
         } else {
             ++iter;
diff --git a/src/gui/kernel/qgesturemanager_p.h b/src/gui/kernel/qgesturemanager_p.h
index a0ff83f..c105c9b 100644
--- a/src/gui/kernel/qgesturemanager_p.h
+++ b/src/gui/kernel/qgesturemanager_p.h
@@ -127,7 +127,7 @@ private:
 
     int m_lastCustomGestureId;
 
-    QHash<QGestureRecognizer *, QList<QGesture *> > m_obsoleteGestures;
+    QHash<QGestureRecognizer *, QSet<QGesture *> > m_obsoleteGestures;
     QHash<QGesture *, QGestureRecognizer *> m_deletedRecognizers;
     void cleanupGesturesForRemovedRecognizer(QGesture *gesture);
 
diff --git a/src/gui/kernel/qwidget.cpp b/src/gui/kernel/qwidget.cpp
index 20d1d30..0334d47 100644
--- a/src/gui/kernel/qwidget.cpp
+++ b/src/gui/kernel/qwidget.cpp
@@ -1388,6 +1388,9 @@ QWidget::~QWidget()
         qWarning("QWidget: %s (%s) deleted while being painted", className(), name());
 #endif
 
+    foreach (Qt::GestureType type, d->gestureContext.keys())
+        ungrabGesture(type);
+
     // force acceptDrops false before winId is destroyed.
     d->registerDropSite(false);