Improved gesture event delivery in graphicsview.

Made it possible to delete a gesture target from a gesture event handler.  It
is still not possible to delete some items (like an item that originated the
gesture, i.e. that that the event that triggered the gesture to start), and in
that case deleteLater() should be used.

Reviewed-by: Andreas Aardal Hanssen

1 files changed, 136 insertions, 3 deletions

diff --git a/tests/auto/gestures/tst_gestures.cpp b/tests/auto/gestures/tst_gestures.cpp
index 1765a30..a2058cd 100644
--- a/tests/auto/gestures/tst_gestures.cpp
+++ b/tests/auto/gestures/tst_gestures.cpp
@@ -261,15 +261,19 @@ protected:
                 eventsPtr->all << g->gestureType();
                 switch(g->state()) {
                 case Qt::GestureStarted:
+                    emit gestureStarted(e->type(), g);
                     eventsPtr->started << g->gestureType();
                     break;
                 case Qt::GestureUpdated:
+                    emit gestureUpdated(e->type(), g);
                     eventsPtr->updated << g->gestureType();
                     break;
                 case Qt::GestureFinished:
+                    emit gestureFinished(e->type(), g);
                     eventsPtr->finished << g->gestureType();
                     break;
                 case Qt::GestureCanceled:
+                    emit gestureCanceled(e->type(), g);
                     eventsPtr->canceled << g->gestureType();
                     break;
                 default:
@@ -283,13 +287,23 @@ protected:
         }
         return true;
     }
+
+Q_SIGNALS:
+    void gestureStarted(QEvent::Type, QGesture *);
+    void gestureUpdated(QEvent::Type, QGesture *);
+    void gestureFinished(QEvent::Type, QGesture *);
+    void gestureCanceled(QEvent::Type, QGesture *);
+
+public Q_SLOTS:
+    void deleteThis() { delete this; }
 };
 
 // TODO rename to sendGestureSequence
 static void sendCustomGesture(CustomEvent *event, QObject *object, QGraphicsScene *scene = 0)
 {
+    QWeakPointer<QObject> receiver(object);
     for (int i = CustomGesture::SerialMaybeThreshold;
-         i <= CustomGesture::SerialFinishedThreshold; ++i) {
+         i <= CustomGesture::SerialFinishedThreshold && receiver; ++i) {
         event->serial = i;
         if (scene)
             scene->sendEvent(qobject_cast<QGraphicsObject *>(object), event);
@@ -336,6 +350,9 @@ private slots:
     void graphicsViewParentPropagation();
     void panelPropagation();
     void panelStacksBehindParent();
+    void deleteGestureTargetWidget();
+    void deleteGestureTargetItem_data();
+    void deleteGestureTargetItem();
 };
 
 tst_Gestures::tst_Gestures()
@@ -657,14 +674,16 @@ static const QColor InstanceColors[] = {
 
 class GestureItem : public QGraphicsObject
 {
+    Q_OBJECT
     static int InstanceCount;
-
 public:
     GestureItem(const char *name = 0)
     {
         instanceNumber = InstanceCount++;
-        if (name)
+        if (name) {
             setObjectName(QLatin1String(name));
+            setToolTip(name);
+        }
         size = QRectF(0, 0, 100, 100);
         customEventsReceived = 0;
         gestureEventsReceived = 0;
@@ -672,6 +691,8 @@ public:
         events.clear();
         overrideEvents.clear();
         acceptGestureOverride = false;
+
+        scene = 0;
     }
     ~GestureItem()
     {
@@ -773,15 +794,19 @@ protected:
                 switch(g->state()) {
                 case Qt::GestureStarted:
                     eventsPtr->started << g->gestureType();
+                    emit gestureStarted(e->type(), g);
                     break;
                 case Qt::GestureUpdated:
                     eventsPtr->updated << g->gestureType();
+                    emit gestureUpdated(e->type(), g);
                     break;
                 case Qt::GestureFinished:
                     eventsPtr->finished << g->gestureType();
+                    emit gestureFinished(e->type(), g);
                     break;
                 case Qt::GestureCanceled:
                     eventsPtr->canceled << g->gestureType();
+                    emit gestureCanceled(e->type(), g);
                     break;
                 default:
                     Q_ASSERT(false);
@@ -794,6 +819,26 @@ protected:
         }
         return true;
     }
+
+Q_SIGNALS:
+    void gestureStarted(QEvent::Type, QGesture *);
+    void gestureUpdated(QEvent::Type, QGesture *);
+    void gestureFinished(QEvent::Type, QGesture *);
+    void gestureCanceled(QEvent::Type, QGesture *);
+
+public:
+    // some arguments for the slots below:
+    QGraphicsScene *scene;
+
+public Q_SLOTS:
+    void deleteThis() { delete this; }
+    void addSelfToScene(QEvent::Type eventType, QGesture *)
+    {
+        if (eventType == QEvent::Gesture) {
+            disconnect(sender(), 0, this, SLOT(addSelfToScene(QEvent::Type,QGesture*)));
+            scene->addItem(this);
+        }
+    }
 };
 int GestureItem::InstanceCount = 0;
 
@@ -1724,5 +1769,93 @@ void tst_Gestures::panelStacksBehindParent()
     QCOMPARE(panel->gestureOverrideEventsReceived, 0);
 }
 
+void tst_Gestures::deleteGestureTargetWidget()
+{
+
+}
+
+void tst_Gestures::deleteGestureTargetItem_data()
+{
+    QTest::addColumn<bool>("propagateUpdateGesture");
+    QTest::addColumn<QString>("emitter");
+    QTest::addColumn<QString>("receiver");
+    QTest::addColumn<QByteArray>("signalName");
+    QTest::addColumn<QByteArray>("slotName");
+
+    QByteArray gestureUpdated = SIGNAL(gestureUpdated(QEvent::Type,QGesture*));
+    QByteArray gestureFinished = SIGNAL(gestureFinished(QEvent::Type,QGesture*));
+    QByteArray deleteThis = SLOT(deleteThis());
+    QByteArray deleteLater = SLOT(deleteLater());
+
+    QTest::newRow("delete1")
+            << false << "item1" << "item1" << gestureUpdated << deleteThis;
+    QTest::newRow("delete2")
+            << false << "item2" << "item2" << gestureUpdated << deleteThis;
+    QTest::newRow("delete3")
+            << false << "item1" << "item2" << gestureUpdated << deleteThis;
+
+    QTest::newRow("deleteLater1")
+            << false << "item1" << "item1" << gestureUpdated << deleteLater;
+    QTest::newRow("deleteLater2")
+            << false << "item2" << "item2" << gestureUpdated << deleteLater;
+    QTest::newRow("deleteLater3")
+            << false << "item1" << "item2" << gestureUpdated << deleteLater;
+    QTest::newRow("deleteLater4")
+            << false << "item2" << "item1" << gestureUpdated << deleteLater;
+
+    QTest::newRow("delete-self-and-propagate")
+            << true << "item2" << "item2" << gestureUpdated << deleteThis;
+    QTest::newRow("deleteLater-self-and-propagate")
+            << true << "item2" << "item2" << gestureUpdated << deleteLater;
+    QTest::newRow("propagate-to-deletedLater")
+            << true << "item2" << "item1" << gestureUpdated << deleteLater;
+}
+
+void tst_Gestures::deleteGestureTargetItem()
+{
+    QFETCH(bool, propagateUpdateGesture);
+    QFETCH(QString, emitter);
+    QFETCH(QString, receiver);
+    QFETCH(QByteArray, signalName);
+    QFETCH(QByteArray, slotName);
+
+    QGraphicsScene scene;
+    QGraphicsView view(&scene);
+    view.setWindowFlags(Qt::X11BypassWindowManagerHint);
+
+    GestureItem *item1 = new GestureItem("item1");
+    item1->grabGesture(CustomGesture::GestureType);
+    item1->setZValue(2);
+    scene.addItem(item1);
+
+    GestureItem *item2 = new GestureItem("item2");
+    item2->grabGesture(CustomGesture::GestureType);
+    item2->setZValue(5);
+    scene.addItem(item2);
+
+    QMap<QString, GestureItem *> items;
+    items.insert(item1->objectName(), item1);
+    items.insert(item2->objectName(), item2);
+
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+    view.ensureVisible(scene.sceneRect());
+
+    view.viewport()->grabGesture(CustomGesture::GestureType, Qt::DontStartGestureOnChildren);
+
+    if (propagateUpdateGesture)
+        item2->ignoredUpdatedGestures << CustomGesture::GestureType;
+    connect(items.value(emitter, 0), signalName, items.value(receiver, 0), slotName);
+
+    // some debug output to see the current test data tag, so if we crash
+    // we know which one caused the crash.
+    qDebug() << "<-- testing";
+
+    CustomEvent event;
+    event.hotSpot = mapToGlobal(QPointF(5, 5), item2, &view);
+    event.hasHotSpot = true;
+    sendCustomGesture(&event, item1, &scene);
+}
+
 QTEST_MAIN(tst_Gestures)
 #include "tst_gestures.moc"