Client: clear focus on touch cancel

When we get a touch_cancel event all touches should be treated as
lifted.

The next frame call focus is set, with no pending touch points but
without having gone through touch_up. We call mPendingTouchPoints.last()
without guards even though it is potentially now empty.

Change-Id: I3719f9507c5d397d8641692271d878076b7c23b8
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Liang Qi <liang.qi@qt.io>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

src/plugins/platforms/wayland/qwaylandinputdevice.cpp

@@ -1412,6 +1412,7 @@ void QWaylandInputDevice::Touch::touch_cancel()
     if (touchExt)
         touchExt->touchCanceled();
 
+    mFocus = nullptr;
     QWindowSystemInterface::handleTouchCancelEvent(nullptr, mParent->mTouchDevice);
 }
 

tests/auto/wayland/seat/tst_seat.cpp

@@ -50,6 +50,7 @@ private slots:
     void multiTouch();
     void multiTouchUpAndMotionFrame();
     void tapAndMoveInSameFrame();
+    void cancelTouch();
 };
 
 void tst_seat::bindsToSeat()
@@ -633,5 +634,34 @@ void tst_seat::tapAndMoveInSameFrame()
     QTRY_COMPARE(window.m_events.last().touchPoints.first().state(), QEventPoint::State::Released);
 }
 
+void tst_seat::cancelTouch()
+{
+    TouchWindow window;
+    QCOMPOSITOR_TRY_VERIFY(xdgSurface() && xdgSurface()->m_committedConfigureSerial);
+
+    exec([=] {
+        auto *t = touch();
+        auto *c = client();
+        t->sendDown(xdgToplevel()->surface(), {32, 32}, 1);
+        t->sendFrame(c);
+        t->sendCancel(c);
+        t->sendFrame(c);
+    });
+
+    QTRY_VERIFY(!window.m_events.empty());
+    {
+        auto e = window.m_events.takeFirst();
+        QCOMPARE(e.type, QEvent::TouchBegin);
+        QCOMPARE(e.touchPointStates, QEventPoint::State::Pressed);
+        QCOMPARE(e.touchPoints.length(), 1);
+        QCOMPARE(e.touchPoints.first().position(), QPointF(32-window.frameMargins().left(), 32-window.frameMargins().top()));
+    }
+    {
+        auto e = window.m_events.takeFirst();
+        QCOMPARE(e.type, QEvent::TouchCancel);
+        QCOMPARE(e.touchPoints.length(), 0);
+    }
+}
+
 QCOMPOSITOR_TEST_MAIN(tst_seat)
 #include "tst_seat.moc"

tests/auto/wayland/shared/coreprotocol.cpp

@@ -493,6 +493,13 @@ void Touch::sendFrame(wl_client *client)
         send_frame(r->handle);
 }
 
+void Touch::sendCancel(wl_client *client)
+{
+    const auto touchResources = resourceMap().values(client);
+    for (auto *r : touchResources)
+        send_cancel(r->handle);
+}
+
 uint Keyboard::sendEnter(Surface *surface)
 {
     auto serial = m_seat->m_compositor->nextSerial();

tests/auto/wayland/shared/coreprotocol.h

@@ -379,6 +379,7 @@ public:
     uint sendUp(wl_client *client, int id);
     void sendMotion(wl_client *client, const QPointF &position, int id);
     void sendFrame(wl_client *client);
+    void sendCancel(wl_client *client);
 
     Seat *m_seat = nullptr;
 };