Use QMutable*Event classes to copy and synthesize events

QMutableTouch/SinglePointEvent can be publicly copy constructed from their
non-mutable counterparts, make use of that.

Change-Id: I7f56a9f9649bb7726cca1eaddccfdc3f21d47554
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

7 files changed, 45 insertions, 46 deletions

diff --git a/src/quick/items/qquickflickable.cpp b/src/quick/items/qquickflickable.cpp
index 9e7b2a4f17..b451c275c2 100644
--- a/src/quick/items/qquickflickable.cpp
+++ b/src/quick/items/qquickflickable.cpp
@@ -1451,10 +1451,9 @@ void QQuickFlickable::mouseReleaseEvent(QMouseEvent *event)
             d->replayDelayedPress();
 
             // Now send the release
-            auto &firstPoint = event->point(0);
-            if (auto grabber = qmlobject_cast<QQuickItem *>(event->exclusiveGrabber(firstPoint))) {
-                QMouseEvent localized(*event);
-                QMutableEventPoint::from(firstPoint).setPosition(grabber->mapFromScene(event->scenePosition()));
+            if (auto grabber = qmlobject_cast<QQuickItem *>(event->exclusiveGrabber(event->point(0)))) {
+                QMutableSinglePointEvent localized(*event);
+                localized.mutablePoint().setPosition(grabber->mapFromScene(localized.scenePosition()));
                 QCoreApplication::sendEvent(window(), &localized);
             }
 
diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index 116d1a370b..5dcc191053 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -8389,7 +8389,7 @@ QQuickItemLayer *QQuickItemPrivate::layer() const
     monitor eventpoint movements until a drag threshold is exceeded or the
     requirements for a gesture to be recognized are met in some other way.
 */
-QTouchEvent QQuickItemPrivate::localizedTouchEvent(const QTouchEvent *event, bool isFiltering)
+void QQuickItemPrivate::localizedTouchEvent(const QTouchEvent *event, bool isFiltering, QMutableTouchEvent *localized)
 {
     Q_Q(QQuickItem);
     QList<QEventPoint> touchPoints;
@@ -8449,8 +8449,10 @@ QTouchEvent QQuickItemPrivate::localizedTouchEvent(const QTouchEvent *event, boo
 
     // Now touchPoints will have only points which are inside the item.
     // But if none of them were just pressed inside, and the item has no other reason to care, ignore them anyway.
-    if (touchPoints.isEmpty() || (!anyPressOrReleaseInside && !anyGrabber && !isFiltering))
-        return QTouchEvent(QEvent::None);
+    if (touchPoints.isEmpty() || (!anyPressOrReleaseInside && !anyGrabber && !isFiltering)) {
+        *localized = QMutableTouchEvent(QEvent::None);
+        return;
+    }
 
     // if all points have the same state, set the event type accordingly
     QEvent::Type eventType = event->type();
@@ -8470,7 +8472,7 @@ QTouchEvent QQuickItemPrivate::localizedTouchEvent(const QTouchEvent *event, boo
     ret.setTarget(q);
     ret.setTimestamp(event->timestamp());
     ret.accept();
-    return ret;
+    *localized = ret;
 }
 
 bool QQuickItemPrivate::hasPointerHandlers() const
diff --git a/src/quick/items/qquickitem_p.h b/src/quick/items/qquickitem_p.h
index 1e33eadeac..b97b9cefd5 100644
--- a/src/quick/items/qquickitem_p.h
+++ b/src/quick/items/qquickitem_p.h
@@ -281,7 +281,7 @@ public:
 
     QQuickItemLayer *layer() const;
 
-    QTouchEvent localizedTouchEvent(const QTouchEvent *event, bool isFiltering);
+    void localizedTouchEvent(const QTouchEvent *event, bool isFiltering, QMutableTouchEvent *localized);
     bool hasPointerHandlers() const;
     bool hasHoverHandlers() const;
     virtual void addPointerHandler(QQuickPointerHandler *h);
diff --git a/src/quick/items/qquickmultipointtoucharea.cpp b/src/quick/items/qquickmultipointtoucharea.cpp
index 23cf6c0351..e23e7365df 100644
--- a/src/quick/items/qquickmultipointtoucharea.cpp
+++ b/src/quick/items/qquickmultipointtoucharea.cpp
@@ -908,21 +908,21 @@ bool QQuickMultiPointTouchArea::sendMouseEvent(QMouseEvent *event)
     QQuickItem *grabber = c ? c->mouseGrabberItem() : nullptr;
     bool stealThisEvent = _stealMouse;
     if ((stealThisEvent || contains(localPos)) && (!grabber || !grabber->keepMouseGrab())) {
-        QMouseEvent mouseEvent = *event;
-        auto mut = QMutableSinglePointEvent::from(&mouseEvent);
-        mut->mutablePoint().setPosition(localPos);
-        mut->setSource(Qt::MouseEventSynthesizedByQt);
+        QMutableSinglePointEvent mouseEvent(*event);
+        mouseEvent.mutablePoint().setPosition(localPos);
+        mouseEvent.setSource(Qt::MouseEventSynthesizedByQt);
         mouseEvent.setAccepted(false);
+        QMouseEvent *pmouseEvent = static_cast<QMouseEvent *>(static_cast<QSinglePointEvent *>(&mouseEvent));
 
         switch (mouseEvent.type()) {
         case QEvent::MouseMove:
-            mouseMoveEvent(&mouseEvent);
+            mouseMoveEvent(pmouseEvent);
             break;
         case QEvent::MouseButtonPress:
-            mousePressEvent(&mouseEvent);
+            mousePressEvent(pmouseEvent);
             break;
         case QEvent::MouseButtonRelease:
-            mouseReleaseEvent(&mouseEvent);
+            mouseReleaseEvent(pmouseEvent);
             break;
         default:
             break;
diff --git a/src/quick/items/qquickpathview.cpp b/src/quick/items/qquickpathview.cpp
index d7f85c288d..d90ae7eb77 100644
--- a/src/quick/items/qquickpathview.cpp
+++ b/src/quick/items/qquickpathview.cpp
@@ -1859,20 +1859,20 @@ bool QQuickPathView::childMouseEventFilter(QQuickItem *i, QEvent *e)
         bool stealThisEvent = d->stealMouse;
         if ((stealThisEvent || contains(localPos)) && (!grabber || !grabber->keepMouseGrab() || grabberDisabled)) {
             // Make a localized copy of the QMouseEvent.
-            QMouseEvent localizedEvent(*static_cast<QMouseEvent *>(pe));
+            QMutableSinglePointEvent localizedEvent(*static_cast<QMouseEvent *>(pe));
             QMutableEventPoint::from(localizedEvent.point(0)).setPosition(localPos);
             localizedEvent.setAccepted(false);
 
             switch (localizedEvent.type()) {
             case QEvent::MouseMove:
-                d->handleMouseMoveEvent(&localizedEvent);
+                d->handleMouseMoveEvent(static_cast<QMouseEvent *>(static_cast<QSinglePointEvent *>(&localizedEvent)));
                 break;
             case QEvent::MouseButtonPress:
-                d->handleMousePressEvent(&localizedEvent);
+                d->handleMousePressEvent(static_cast<QMouseEvent *>(static_cast<QSinglePointEvent *>(&localizedEvent)));
                 stealThisEvent = d->stealMouse;   // Update stealThisEvent in case changed by function call above
                 break;
             case QEvent::MouseButtonRelease:
-                d->handleMouseReleaseEvent(&localizedEvent);
+                d->handleMouseReleaseEvent(static_cast<QMouseEvent *>(static_cast<QSinglePointEvent *>(&localizedEvent)));
                 break;
             default:
                 break;
diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index 8183988835..e09723e973 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -868,18 +868,15 @@ QQmlListProperty<QObject> QQuickWindowPrivate::data()
                                      QQuickWindowPrivate::data_removeLast);
 }
 
-QMouseEvent QQuickWindowPrivate::touchToMouseEvent(QEvent::Type type, const QEventPoint &p, QTouchEvent *event, QQuickItem *item)
+void QQuickWindowPrivate::touchToMouseEvent(QEvent::Type type, const QEventPoint &p, const QTouchEvent *touchEvent, QMutableSinglePointEvent *mouseEvent)
 {
-    Q_UNUSED(item)
     Q_ASSERT(QCoreApplication::testAttribute(Qt::AA_SynthesizeMouseForUnhandledTouchEvents));
-    QMutableSinglePointEvent ret(type, event->pointingDevice(), p,
+    QMutableSinglePointEvent ret(type, touchEvent->pointingDevice(), p,
                                  (type == QEvent::MouseMove ? Qt::NoButton : Qt::LeftButton),
                                  (type == QEvent::MouseButtonRelease ? Qt::NoButton : Qt::LeftButton),
-                                 event->modifiers(), Qt::MouseEventSynthesizedByQt);
+                                 touchEvent->modifiers(), Qt::MouseEventSynthesizedByQt);
     ret.setAccepted(true); // this now causes the persistent touchpoint to be accepted too
-    ret.setTimestamp(event->timestamp());
-    static_assert(sizeof(QMutableSinglePointEvent) == sizeof(QMouseEvent));
-    return *static_cast<QMouseEvent*>(static_cast<QSinglePointEvent*>(&ret));
+    *mouseEvent = ret;
 }
 
 bool QQuickWindowPrivate::checkIfDoubleTapped(ulong newPressEventTimestamp, QPoint newPressPos)
@@ -947,7 +944,8 @@ bool QQuickWindowPrivate::deliverTouchAsMouse(QQuickItem *item, QTouchEvent *poi
     }
 
     // FIXME: make this work for mouse events too and get rid of the asTouchEvent in here.
-    QTouchEvent event = QQuickItemPrivate::get(item)->localizedTouchEvent(pointerEvent, false);
+    QMutableTouchEvent event;
+    QQuickItemPrivate::get(item)->localizedTouchEvent(pointerEvent, false, &event);
     if (!event.points().count())
         return false;
 
@@ -964,7 +962,8 @@ bool QQuickWindowPrivate::deliverTouchAsMouse(QQuickItem *item, QTouchEvent *poi
                 break;
 
             qCDebug(DBG_TOUCH_TARGET) << device << "TP (mouse)" << Qt::hex << p.id() << "->" << item;
-            QMouseEvent mousePress = touchToMouseEvent(QEvent::MouseButtonPress, p, &event, item);
+            QMutableSinglePointEvent mousePress(QEvent::None, nullptr, QEventPoint());
+            touchToMouseEvent(QEvent::MouseButtonPress, p, &event, &mousePress);
 
             // Send a single press and see if that's accepted
             QCoreApplication::sendEvent(item, &mousePress);
@@ -979,7 +978,8 @@ bool QQuickWindowPrivate::deliverTouchAsMouse(QQuickItem *item, QTouchEvent *poi
                 if (checkIfDoubleTapped(event.timestamp(), p.globalPosition().toPoint())) {
                     // since we synth the mouse event from from touch, we respect the
                     // QPlatformTheme::TouchDoubleTapDistance instead of QPlatformTheme::MouseDoubleClickDistance
-                    QMouseEvent mouseDoubleClick = touchToMouseEvent(QEvent::MouseButtonDblClick, p, &event, item);
+                    QMutableSinglePointEvent mouseDoubleClick(QEvent::None, nullptr, QEventPoint());
+                    touchToMouseEvent(QEvent::MouseButtonDblClick, p, &event, &mouseDoubleClick);
                     QCoreApplication::sendEvent(item, &mouseDoubleClick);
                     event.setAccepted(mouseDoubleClick.isAccepted());
                     if (!mouseDoubleClick.isAccepted())
@@ -1000,7 +1000,8 @@ bool QQuickWindowPrivate::deliverTouchAsMouse(QQuickItem *item, QTouchEvent *poi
                         touchMousePressTimestamp = 0;   // Got dragged too far, dismiss the double tap
                 }
                 if (QQuickItem *mouseGrabberItem = qmlobject_cast<QQuickItem *>(pointerEvent->exclusiveGrabber(p))) {
-                    QMouseEvent me = touchToMouseEvent(QEvent::MouseMove, p, &event, mouseGrabberItem);
+                    QMutableSinglePointEvent me(QEvent::None, nullptr, QEventPoint());
+                    touchToMouseEvent(QEvent::MouseMove, p, &event, &me);
                     QCoreApplication::sendEvent(item, &me);
                     event.setAccepted(me.isAccepted());
                     if (me.isAccepted())
@@ -1010,7 +1011,8 @@ bool QQuickWindowPrivate::deliverTouchAsMouse(QQuickItem *item, QTouchEvent *poi
                     // no grabber, check if we care about mouse hover
                     // FIXME: this should only happen once, not recursively... I'll ignore it just ignore hover now.
                     // hover for touch???
-                    QMouseEvent me = touchToMouseEvent(QEvent::MouseMove, p, &event, item);
+                    QMutableSinglePointEvent me(QEvent::None, nullptr, QEventPoint());
+                    touchToMouseEvent(QEvent::MouseMove, p, &event, &me);
                     if (lastMousePosition.isNull())
                         lastMousePosition = me.scenePosition();
                     QPointF last = lastMousePosition;
@@ -1026,7 +1028,8 @@ bool QQuickWindowPrivate::deliverTouchAsMouse(QQuickItem *item, QTouchEvent *poi
             } else if (p.state() & QEventPoint::State::Released) {
                 // currently handled point was released
                 if (QQuickItem *mouseGrabberItem = qmlobject_cast<QQuickItem *>(pointerEvent->exclusiveGrabber(p))) {
-                    QMouseEvent me = touchToMouseEvent(QEvent::MouseButtonRelease, p, &event, mouseGrabberItem);
+                    QMutableSinglePointEvent me(QEvent::None, nullptr, QEventPoint());
+                    touchToMouseEvent(QEvent::MouseButtonRelease, p, &event, &me);
                     QCoreApplication::sendEvent(item, &me);
 
                     if (item->acceptHoverEvents() && p.globalPosition() != QGuiApplicationPrivate::lastCursorPosition) {
@@ -2057,14 +2060,7 @@ void QQuickWindowPrivate::deliverKeyEvent(QKeyEvent *e)
 */
 QPointerEvent *QQuickWindowPrivate::clonePointerEvent(QPointerEvent *event, std::optional<QPointF> transformedLocalPos)
 {
-    QPointerEvent *ret = nullptr;
-    if (isMouseEvent(event)) {
-        ret = new QMouseEvent(*(static_cast<QMouseEvent *>(event)));
-    } else if (isTouchEvent(event)) {
-        ret = new QTouchEvent(*(static_cast<QTouchEvent *>(event)));
-    } else if (isTabletEvent(event)) {
-        ret = new QTabletEvent(*(static_cast<QTabletEvent *>(event)));
-    }
+    QPointerEvent *ret = static_cast<QPointerEvent*>(event->clone());
     QMutableEventPoint &point = QMutableEventPoint::from(ret->point(0));
     point.detach();
     point.setTimestamp(event->timestamp());
@@ -2945,7 +2941,8 @@ void QQuickWindowPrivate::deliverMatchingPointsToItem(QQuickItem *item, bool isG
         return;
 
     bool eventAccepted = false;
-    QTouchEvent touchEvent = QQuickItemPrivate::get(item)->localizedTouchEvent(static_cast<QTouchEvent *>(pointerEvent), false);
+    QMutableTouchEvent touchEvent;
+    QQuickItemPrivate::get(item)->localizedTouchEvent(static_cast<QTouchEvent *>(pointerEvent), false, &touchEvent);
     if (touchEvent.type() == QEvent::None)
         return;  // no points inside this item
 
@@ -3261,8 +3258,8 @@ bool QQuickWindowPrivate::sendFilteredPointerEventImpl(QPointerEvent *event, QQu
             } else if (acceptsTouchEvents || receiver->acceptedMouseButtons()) {
                 // get a touch event customized for delivery to filteringParent
                 // TODO should not be necessary? because QQuickWindowPrivate::deliverMatchingPointsToItem() does it
-                QTouchEvent filteringParentTouchEvent =
-                        QQuickItemPrivate::get(receiver)->localizedTouchEvent(static_cast<QTouchEvent *>(event), true);
+                QMutableTouchEvent filteringParentTouchEvent;
+                QQuickItemPrivate::get(receiver)->localizedTouchEvent(static_cast<QTouchEvent *>(event), true, &filteringParentTouchEvent);
                 if (filteringParentTouchEvent.type() != QEvent::None) {
                     qCDebug(DBG_TOUCH) << "letting parent" << filteringParent << "filter for" << receiver << &filteringParentTouchEvent;
                     if (filteringParent->childMouseEventFilter(receiver, &filteringParentTouchEvent)) {
@@ -3299,7 +3296,8 @@ bool QQuickWindowPrivate::sendFilteredPointerEventImpl(QPointerEvent *event, QQu
                             if (touchMouseUnset || touchMouseId == tp.id()) {
                                 // convert filteringParentTouchEvent (which is already transformed wrt local position, velocity, etc.)
                                 // into a synthetic mouse event, and let childMouseEventFilter() have another chance with that
-                                QMouseEvent mouseEvent = touchToMouseEvent(t, tp, &filteringParentTouchEvent, receiver);
+                                QMutableSinglePointEvent mouseEvent(QEvent::None, nullptr, QEventPoint());
+                                touchToMouseEvent(t, tp, &filteringParentTouchEvent, &mouseEvent);
                                 // If a filtering item calls QQuickWindow::mouseGrabberItem(), it should
                                 // report the touchpoint's grabber.  Whenever we send a synthetic mouse event,
                                 // touchMouseId and touchMouseDevice must be set, even if it's only temporarily and isn't grabbed.
diff --git a/src/quick/items/qquickwindow_p.h b/src/quick/items/qquickwindow_p.h
index 3be6f5cd8c..18a43487c1 100644
--- a/src/quick/items/qquickwindow_p.h
+++ b/src/quick/items/qquickwindow_p.h
@@ -197,7 +197,7 @@ public:
     static bool isTabletEvent(const QPointerEvent *ev);
 
     // delivery of pointer events:
-    QMouseEvent touchToMouseEvent(QEvent::Type type, const QEventPoint &p, QTouchEvent *event, QQuickItem *item);
+    void touchToMouseEvent(QEvent::Type type, const QEventPoint &p, const QTouchEvent *touchEvent, QMutableSinglePointEvent *mouseEvent);
     void ensureDeviceConnected(const QPointingDevice *dev);
     void deliverPointerEvent(QPointerEvent *);
     bool deliverTouchCancelEvent(QTouchEvent *);