Send a touch cancel event when we stop getting input

Take a grab when a touch gesture begins and send a touch cancel event
when we lose the grab. That makes sure that we don't leave the client
with a broken input state if some item like Flickable steals the
events from the QWaylandSurfaceItem.

Change-Id: I1e07836041a25cdbabff0d8559c4e06cbac27e7e
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/src/compositor/compositor_api/qwaylandsurfaceitem.cpp b/src/compositor/compositor_api/qwaylandsurfaceitem.cpp
index 1099eb764..35e0cd285 100644
--- a/src/compositor/compositor_api/qwaylandsurfaceitem.cpp
+++ b/src/compositor/compositor_api/qwaylandsurfaceitem.cpp
@@ -217,6 +217,12 @@ void QWaylandSurfaceItem::keyReleaseEvent(QKeyEvent *event)
 void QWaylandSurfaceItem::touchEvent(QTouchEvent *event)
 {
     if (m_touchEventsEnabled) {
+        if (event->type() == QEvent::TouchBegin) {
+            QQuickItem *grabber = window()->mouseGrabberItem();
+            if (grabber != this)
+                grabMouse();
+        }
+
         QWaylandInputDevice *inputDevice = compositor()->defaultInputDevice();
         event->accept();
         if (inputDevice->mouseFocus() != this) {
@@ -232,6 +238,14 @@ void QWaylandSurfaceItem::touchEvent(QTouchEvent *event)
     }
 }
 
+void QWaylandSurfaceItem::mouseUngrabEvent()
+{
+    if (surface()) {
+        QTouchEvent e(QEvent::TouchCancel);
+        touchEvent(&e);
+    }
+}
+
 void QWaylandSurfaceItem::takeFocus()
 {
     setFocus(true);
diff --git a/src/compositor/compositor_api/qwaylandsurfaceitem.h b/src/compositor/compositor_api/qwaylandsurfaceitem.h
index 93283355f..2805db52a 100644
--- a/src/compositor/compositor_api/qwaylandsurfaceitem.h
+++ b/src/compositor/compositor_api/qwaylandsurfaceitem.h
@@ -100,6 +100,7 @@ protected:
     void keyReleaseEvent(QKeyEvent *event);
 
     void touchEvent(QTouchEvent *event);
+    void mouseUngrabEvent() Q_DECL_OVERRIDE;
 
 public slots:
     void takeFocus();