xcb: fix QWindow::startSystemMove()/Resize() triggered by touch

Abort the system move/resise at XCB_INPUT_TOUCH_END.

Limit the behavior only on supported platforms, such as KDE and
OpenBox.

Change-Id: I53c86979ca56f4de8c5cf2807f781abdad6987b2
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

4 files changed, 19 insertions, 7 deletions

diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index 58a4a8ea04..e1c9bf80fc 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection.cpp
@@ -96,8 +96,6 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, bool canGra
 
     m_eventQueue = new QXcbEventQueue(this);
 
-    m_xdgCurrentDesktop = qgetenv("XDG_CURRENT_DESKTOP").toLower();
-
     if (hasXRandr())
         xrandrSelectEvents();
 
@@ -795,6 +793,15 @@ void QXcbConnection::ungrabServer()
         xcb_ungrab_server(xcb_connection());
 }
 
+QString QXcbConnection::windowManagerName() const
+{
+    QXcbVirtualDesktop *pvd = primaryVirtualDesktop();
+    if (pvd)
+        return pvd->windowManagerName().toLower();
+
+    return QString();
+}
+
 xcb_timestamp_t QXcbConnection::getTimestamp()
 {
     // send a dummy event to myself to get the timestamp from X server.
diff --git a/src/plugins/platforms/xcb/qxcbconnection.h b/src/plugins/platforms/xcb/qxcbconnection.h
index 556e6b1002..a7db3eda89 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.h
+++ b/src/plugins/platforms/xcb/qxcbconnection.h
@@ -213,8 +213,7 @@ public:
     void grabServer();
     void ungrabServer();
 
-    bool isUnity() const { return m_xdgCurrentDesktop == "unity"; }
-    bool isGnome() const { return m_xdgCurrentDesktop == "gnome"; }
+    QString windowManagerName() const;
 
     QXcbNativeInterface *nativeInterface() const { return m_nativeInterface; }
 
@@ -378,7 +377,6 @@ private:
 
     friend class QXcbEventQueue;
 
-    QByteArray m_xdgCurrentDesktop;
     QTimer m_focusInTimer;
 
 };
diff --git a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp b/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
index 0e79f35d60..4657c2ac89 100644
--- a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
@@ -648,6 +648,9 @@ void QXcbConnection::xi2HandleEvent(xcb_ge_event_t *event)
         if (xiEvent->event_type == XCB_INPUT_BUTTON_RELEASE
             && xiEvent->detail == XCB_BUTTON_INDEX_1 ) {
             abortSystemMoveResize(xiEvent->event);
+        } else if (xiEvent->event_type == XCB_INPUT_TOUCH_END) {
+            abortSystemMoveResize(xiEvent->event);
+            return;
         } else {
             return;
         }
@@ -921,6 +924,8 @@ bool QXcbConnection::startSystemMoveResizeForTouch(xcb_window_t window, int edge
                     m_startSystemMoveResizeInfo.deviceid = devIt.key();
                     m_startSystemMoveResizeInfo.pointid = pointIt.key();
                     m_startSystemMoveResizeInfo.edges = edges;
+                    setDuringSystemMoveResize(true);
+                    qCDebug(lcQpaXInputDevices) << "triggered system move or resize from touch";
                     return true;
                 }
             }
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 122e89f22e..ea8e1f479d 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -2332,8 +2332,10 @@ bool QXcbWindow::startSystemMoveResize(const QPoint &pos, int edges)
     // ### FIXME QTBUG-53389
     bool startedByTouch = connection()->startSystemMoveResizeForTouch(m_window, edges);
     if (startedByTouch) {
-        if (connection()->isUnity()) {
-            // Unity fails to move/resize via _NET_WM_MOVERESIZE (WM bug?).
+        const QString wmname = connection()->windowManagerName();
+        if (wmname != QLatin1String("kwin") && wmname != QLatin1String("openbox")) {
+            qCDebug(lcQpaXInputDevices) << "only KDE and OpenBox support startSystemMove/Resize which is triggered from touch events: XDG_CURRENT_DESKTOP="
+                                        << qgetenv("XDG_CURRENT_DESKTOP");
             connection()->abortSystemMoveResize(m_window);
             return false;
         }