TapHandler: ignore scroll events and native gestures

During a 2-finger press (to emulate right click on a trackpad), the
OS may also generate a QWheelEvent with ScrollBegin phase just in case
scrolling starts.  This must not prematurely deactivate the TapHandler.

Also if a gesture or wheel event begins as the very first event after
an application starts, ensure that subsequent mouse events are not
mis-delivered as wheel or gesture events.

Fixes: QTBUG-71955
Change-Id: Ic12e116483ab9ad37c4ac3b1d10ccb62e1349e0a
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

src/quick/handlers/qquicktaphandler.cpp

@@ -107,6 +107,10 @@ static bool dragOverThreshold(const QQuickEventPoint *point)
 
 bool QQuickTapHandler::wantsEventPoint(QQuickEventPoint *point)
 {
+    if (!point->pointerEvent()->asPointerMouseEvent() &&
+            !point->pointerEvent()->asPointerTouchEvent() &&
+            !point->pointerEvent()->asPointerTabletEvent() )
+        return false;
     // If the user has not violated any constraint, it could be a tap.
     // Otherwise we want to give up the grab so that a competing handler
     // (e.g. DragHandler) gets a chance to take over.

src/quick/items/qquickwindow.cpp

@@ -2246,13 +2246,14 @@ QQuickPointerEvent *QQuickWindowPrivate::queryPointerEventInstance(QQuickPointer
 {
     // Search for a matching reusable event object.
     for (QQuickPointerEvent *e : pointerEventInstances) {
-        // If device can generate native gestures (e.g. a trackpad), there might be two QQuickPointerEvents:
-        // QQuickPointerNativeGestureEvent and QQuickPointerTouchEvent.  Use eventType to disambiguate.
+        // If device can generate native gestures (e.g. a trackpad), there might be multiple QQuickPointerEvents:
+        // QQuickPointerNativeGestureEvent, QQuickPointerScrollEvent, and QQuickPointerTouchEvent.
+        // Use eventType to disambiguate.
 #if QT_CONFIG(gestures)
-        if (eventType == QEvent::NativeGesture && !qobject_cast<QQuickPointerNativeGestureEvent*>(e))
+        if ((eventType == QEvent::NativeGesture) != bool(e->asPointerNativeGestureEvent()))
             continue;
 #endif
-        if (eventType == QEvent::Wheel && !qobject_cast<QQuickPointerScrollEvent*>(e))
+        if ((eventType == QEvent::Wheel) != bool(e->asPointerScrollEvent()))
             continue;
         // Otherwise we assume there's only one event type per device.
         // More disambiguation tests might need to be added above if that changes later.

tests/auto/quick/pointerhandlers/qquicktaphandler/data/rightTapHandler.qml

@@ -0,0 +1,41 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.12
+
+Rectangle {
+    width: 320
+    height: 240
+    color: rightTap.pressed ? "tomato" : "beige"
+    TapHandler {
+        id: rightTap
+        objectName: "right button TapHandler"
+        longPressThreshold: 0.5
+        acceptedButtons: Qt.RightButton
+    }
+}

tests/auto/quick/pointerhandlers/qquicktaphandler/tst_qquicktaphandler.cpp

@@ -69,6 +69,7 @@ private slots:
     void mouseLongPress();
     void buttonsMultiTouch();
     void componentUserBehavioralOverride();
+    void rightLongPressIgnoreWheel();
 
 private:
     void createView(QScopedPointer<QQuickView> &window, const char *fileName);
@@ -622,6 +623,44 @@ void tst_TapHandler::componentUserBehavioralOverride()
     QCOMPARE(userGrabChangedSpy.count(), 2);
 }
 
+void tst_TapHandler::rightLongPressIgnoreWheel()
+{
+    QScopedPointer<QQuickView> windowPtr;
+    createView(windowPtr, "rightTapHandler.qml");
+    QQuickView * window = windowPtr.data();
+
+    QQuickTapHandler *tap = window->rootObject()->findChild<QQuickTapHandler*>();
+    QVERIFY(tap);
+    QSignalSpy tappedSpy(tap, SIGNAL(tapped(QQuickEventPoint *)));
+    QSignalSpy longPressedSpy(tap, SIGNAL(longPressed()));
+    QPoint p1(100, 100);
+
+    // Mouse wheel with ScrollBegin phase (because as soon as two fingers are touching
+    // the trackpad, it will send such an event: QTBUG-71955)
+    {
+        QWheelEvent wheelEvent(p1, p1, QPoint(0, 0), QPoint(0, 0),
+                               Qt::NoButton, Qt::NoModifier, Qt::ScrollBegin, false, Qt::MouseEventNotSynthesized);
+        QGuiApplication::sendEvent(window, &wheelEvent);
+    }
+
+    // Press
+    QTest::mousePress(window, Qt::RightButton, Qt::NoModifier, p1);
+    QTRY_COMPARE(tap->isPressed(), true);
+
+    // Mouse wheel ScrollEnd phase
+    QWheelEvent wheelEvent(p1, p1, QPoint(0, 0), QPoint(0, 0),
+                           Qt::NoButton, Qt::NoModifier, Qt::ScrollEnd, false, Qt::MouseEventNotSynthesized);
+    QGuiApplication::sendEvent(window, &wheelEvent);
+    QTRY_COMPARE(longPressedSpy.count(), 1);
+    QCOMPARE(tap->isPressed(), true);
+    QCOMPARE(tappedSpy.count(), 0);
+
+    // Release
+    QTest::mouseRelease(window, Qt::RightButton, Qt::NoModifier, p1, 500);
+    QTRY_COMPARE(tap->isPressed(), false);
+    QCOMPARE(tappedSpy.count(), 0);
+}
+
 QTEST_MAIN(tst_TapHandler)
 
 #include "tst_qquicktaphandler.moc"