QGuiApplication: port the last user of QMutableEventPoint::from()

... to the new static setter API, preventing the undefined behavior
that from() depended on.

Remove from() and constFrom().

Task-number: QTBUG-99615
Pick-to: 6.3
Change-Id: I69c52aa286eaf51303734e42184af36815cf828a
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

3 files changed, 40 insertions, 44 deletions

diff --git a/src/gui/kernel/qeventpoint.cpp b/src/gui/kernel/qeventpoint.cpp
index fc72099c19..62f3ecd975 100644
--- a/src/gui/kernel/qeventpoint.cpp
+++ b/src/gui/kernel/qeventpoint.cpp
@@ -524,8 +524,8 @@ void QMutableEventPoint::detach(QEventPoint &p)
 }
 
 /*! \internal
-    Update current state from the given \a other point, assuming that this
-    instance contains state from the previous event and \a other contains new
+    Update \a target state from the \a other point, assuming that \a target
+    contains state from the previous event and \a other contains new
     values that came in from a device.
 
     That is: global position and other valuators will be updated, but
@@ -537,40 +537,40 @@ void QMutableEventPoint::detach(QEventPoint &p)
     \li properties that should be persistent between events (such as grabbers)
     \endlist
 */
-void QMutableEventPoint::updateFrom(const QEventPoint &other)
+void QMutableEventPoint::update(const QEventPoint &other, QEventPoint &target)
 {
-    detach();
-    setPressure(other.pressure());
+    detach(target);
+    setPressure(target, other.pressure());
 
     switch (other.state()) {
     case QEventPoint::State::Pressed:
-        setGlobalPressPosition(other.globalPosition());
-        setGlobalLastPosition(other.globalPosition());
-        if (pressure() < 0)
-            setPressure(1);
+        setGlobalPressPosition(target, other.globalPosition());
+        setGlobalLastPosition(target, other.globalPosition());
+        if (target.pressure() < 0)
+            setPressure(target, 1);
         break;
 
     case QEventPoint::State::Released:
-        if (globalPosition() != other.globalPosition())
-            setGlobalLastPosition(globalPosition());
-        setPressure(0);
+        if (target.globalPosition() != other.globalPosition())
+            setGlobalLastPosition(target, target.globalPosition());
+        setPressure(target, 0);
         break;
 
     default: // update or stationary
-        if (globalPosition() != other.globalPosition())
-            setGlobalLastPosition(globalPosition());
-        if (pressure() < 0)
-            setPressure(1);
+        if (target.globalPosition() != other.globalPosition())
+            setGlobalLastPosition(target, target.globalPosition());
+        if (target.pressure() < 0)
+            setPressure(target, 1);
         break;
     }
 
-    setState(other.state());
-    setPosition(other.position());
-    setScenePosition(other.scenePosition());
-    setGlobalPosition(other.globalPosition());
-    setEllipseDiameters(other.ellipseDiameters());
-    setRotation(other.rotation());
-    setVelocity(other.velocity());
+    setState(target, other.state());
+    setPosition(target, other.position());
+    setScenePosition(target, other.scenePosition());
+    setGlobalPosition(target, other.globalPosition());
+    setEllipseDiameters(target, other.ellipseDiameters());
+    setRotation(target, other.rotation());
+    setVelocity(target, other.velocity());
 }
 
 /*! \internal
diff --git a/src/gui/kernel/qeventpoint_p.h b/src/gui/kernel/qeventpoint_p.h
index 1cd32fd536..caadb49ca5 100644
--- a/src/gui/kernel/qeventpoint_p.h
+++ b/src/gui/kernel/qeventpoint_p.h
@@ -133,13 +133,7 @@ public:
         d->pos = position;
     }
 
-    void updateFrom(const QEventPoint &other);
-
-    static QMutableEventPoint *from(QEventPoint *me) { return static_cast<QMutableEventPoint *>(me); }
-
-    static QMutableEventPoint &from(QEventPoint &me) { return static_cast<QMutableEventPoint &>(me); }
-
-    static const QMutableEventPoint &constFrom(const QEventPoint &me) { return static_cast<const QMutableEventPoint &>(me); }
+    static void update(const QEventPoint &from, QEventPoint &to);
 
     void detach() { detach(*this); }
     static void detach(QEventPoint &p);
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 5ace7049c7..51de8580f7 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -2849,7 +2849,7 @@ void QGuiApplicationPrivate::processTouchEvent(QWindowSystemInterfacePrivate::To
     for (auto &tempPt : e->points) {
         // update state
         auto epd = devPriv->pointById(tempPt.id());
-        auto &mut = QMutableEventPoint::from(epd->eventPoint);
+        auto &ep = epd->eventPoint;
         epd->eventPoint.setAccepted(false);
         switch (tempPt.state()) {
         case QEventPoint::State::Pressed:
@@ -2859,19 +2859,21 @@ void QGuiApplicationPrivate::processTouchEvent(QWindowSystemInterfacePrivate::To
             // If the QPA event didn't tell us which window, find the one under the touchpoint position.
             if (!window)
                 window = QGuiApplication::topLevelAt(tempPt.globalPosition().toPoint());
-            mut.setWindow(window);
+            QMutableEventPoint::setWindow(ep, window);
             break;
 
         case QEventPoint::State::Released:
-            if (Q_UNLIKELY(!window.isNull() && window != mut.window()))
-                qCWarning(lcPtrDispatch) << "delivering touch release to same window" << mut.window() << "not" << window.data();
-            window = mut.window();
+            if (Q_UNLIKELY(!window.isNull() && window != QMutableEventPoint::window(ep)))
+                qCWarning(lcPtrDispatch) << "delivering touch release to same window"
+                                         << QMutableEventPoint::window(ep) << "not" << window.data();
+            window = QMutableEventPoint::window(ep);
             break;
 
         default: // update or stationary
-            if (Q_UNLIKELY(!window.isNull() && window != mut.window()))
-                qCWarning(lcPtrDispatch) << "delivering touch update to same window" << mut.window() << "not" << window.data();
-            window = mut.window();
+            if (Q_UNLIKELY(!window.isNull() && window != QMutableEventPoint::window(ep)))
+                qCWarning(lcPtrDispatch) << "delivering touch update to same window"
+                                         << QMutableEventPoint::window(ep) << "not" << window.data();
+            window = QMutableEventPoint::window(ep);
             break;
         }
         // If we somehow still don't have a window, we can't deliver this touchpoint.  (should never happen)
@@ -2879,30 +2881,30 @@ void QGuiApplicationPrivate::processTouchEvent(QWindowSystemInterfacePrivate::To
             qCWarning(lcPtrDispatch) << "skipping" << &tempPt << ": no target window";
             continue;
         }
-        mut.updateFrom(tempPt);
+        QMutableEventPoint::update(tempPt, ep);
 
         Q_ASSERT(window.data() != nullptr);
 
         // make the *scene* position the same as the *global* position
-        mut.setScenePosition(tempPt.globalPosition());
+        QMutableEventPoint::setScenePosition(ep, tempPt.globalPosition());
 
         // store the scene position as local position, for now
-        mut.setPosition(window->mapFromGlobal(tempPt.globalPosition()));
+        QMutableEventPoint::setPosition(ep, window->mapFromGlobal(tempPt.globalPosition()));
 
         // setTimeStamp has side effects, so we do it last
-        mut.setTimestamp(e->timestamp);
+        QMutableEventPoint::setTimestamp(ep, e->timestamp);
 
         // add the touchpoint to the event that will be delivered to the window
         bool added = false;
         for (QMutableTouchEvent &ev : touchEvents) {
             if (ev.target() == window.data()) {
-                ev.addPoint(mut);
+                ev.addPoint(ep);
                 added = true;
                 break;
             }
         }
         if (!added) {
-            QMutableTouchEvent mte(e->touchType, device, e->modifiers, {mut});
+            QMutableTouchEvent mte(e->touchType, device, e->modifiers, {ep});
             mte.setTimestamp(e->timestamp);
             mte.setTarget(window.data());
             touchEvents.append(mte);