Introduce QEvent::isSinglePointEvent()

This makes high-level event dispatching easier: for example we often
need to cast an event to access getters like button() and buttons().
We can so far assume that any QPointerEvent that is not a QTouchEvent
is a QSinglePointEvent; but more explicit type-checking looks safer.

Implemented in a similar way as c7f727996909338c3689396160f3060480521846.

Change-Id: I980d759e2a7538b6b30fd3bdc3be0c351ec6c246
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

2 files changed, 21 insertions, 3 deletions

diff --git a/src/gui/kernel/qevent.cpp b/src/gui/kernel/qevent.cpp
index 9d27961071..5e9643d82f 100644
--- a/src/gui/kernel/qevent.cpp
+++ b/src/gui/kernel/qevent.cpp
@@ -164,6 +164,13 @@ QInputEvent::QInputEvent(QEvent::Type type, QEvent::PointerEventTag, const QInpu
 /*!
   \internal
 */
+QInputEvent::QInputEvent(QEvent::Type type, QEvent::SinglePointEventTag, const QInputDevice *dev, Qt::KeyboardModifiers modifiers)
+    : QEvent(type, QEvent::SinglePointEventTag{}), m_dev(dev), m_modState(modifiers)
+{}
+
+/*!
+  \internal
+*/
 QInputEvent::~QInputEvent()
 {
 }
@@ -256,6 +263,14 @@ QPointerEvent::QPointerEvent(QEvent::Type type, const QPointingDevice *dev,
 {
 }
 
+/*!
+  \internal
+*/
+QPointerEvent::QPointerEvent(QEvent::Type type, QEvent::SinglePointEventTag, const QInputDevice *dev, Qt::KeyboardModifiers modifiers)
+    : QInputEvent(type, QEvent::SinglePointEventTag{}, dev, modifiers)
+{
+}
+
 QPointerEvent::~QPointerEvent()
 {
 }
@@ -500,7 +515,7 @@ void QPointerEvent::clearPassiveGrabbers(const QEventPoint &point)
 */
 QSinglePointEvent::QSinglePointEvent(QEvent::Type type, const QPointingDevice *dev, const QPointF &localPos, const QPointF &scenePos,
                                      const QPointF &globalPos, Qt::MouseButton button, Qt::MouseButtons buttons, Qt::KeyboardModifiers modifiers)
-    : QPointerEvent(type, dev, modifiers),
+    : QPointerEvent(type, QEvent::SinglePointEventTag{}, dev, modifiers),
       m_button(button),
       m_mouseState(buttons),
       m_source(Qt::MouseEventNotSynthesized),
@@ -548,7 +563,7 @@ QSinglePointEvent::QSinglePointEvent(QEvent::Type type, const QPointingDevice *d
 QSinglePointEvent::QSinglePointEvent(QEvent::Type type, const QPointingDevice *dev, const QEventPoint &point,
                                      Qt::MouseButton button, Qt::MouseButtons buttons,
                                      Qt::KeyboardModifiers modifiers, Qt::MouseEventSource source)
-    : QPointerEvent(type, dev, modifiers),
+    : QPointerEvent(type, QEvent::SinglePointEventTag{}, dev, modifiers),
       m_button(button),
       m_mouseState(buttons),
       m_source(source),
diff --git a/src/gui/kernel/qevent.h b/src/gui/kernel/qevent.h
index 4bd7a54022..7e35a1b117 100644
--- a/src/gui/kernel/qevent.h
+++ b/src/gui/kernel/qevent.h
@@ -85,7 +85,8 @@ public:
     virtual void setTimestamp(ulong timestamp) { m_timeStamp = timestamp; }
 
 protected:
-    QInputEvent(Type type, PointerEventTag, const QInputDevice *m_dev, Qt::KeyboardModifiers modifiers = Qt::NoModifier);
+    QInputEvent(Type type, PointerEventTag, const QInputDevice *dev, Qt::KeyboardModifiers modifiers = Qt::NoModifier);
+    QInputEvent(Type type, SinglePointEventTag, const QInputDevice *dev, Qt::KeyboardModifiers modifiers = Qt::NoModifier);
 
     const QInputDevice *m_dev = nullptr;
     Qt::KeyboardModifiers m_modState = Qt::NoModifier;
@@ -122,6 +123,8 @@ public:
     bool removePassiveGrabber(const QEventPoint &point, QObject *grabber);
 
 protected:
+    QPointerEvent(Type type, SinglePointEventTag, const QInputDevice *dev, Qt::KeyboardModifiers modifiers = Qt::NoModifier);
+
     QList<QEventPoint> m_points;
 };