dix: when ungrabbing an active grab, accept pointer grabs (#66720)

Ungrabbing a device during an active touch grab rejects the grab. Ungrabbing
a device during an active pointer grab accepts the grab.

Rejection is not really an option for a pointer-emulated grab, if a client
has a button mask on the window it would get a ButtonPress emulated after
UngrabDevice. That is against the core grab behaviour.

X.Org Bug 66720 <http://bugs.freedesktop.org/show_bug.cgi?id=66720>

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Jasper St. Pierre <jstpierre@mecheye.net>

1 files changed, 23 insertions, 12 deletions

diff --git a/Xi/exevents.c b/Xi/exevents.c
index 2bbc6f091..fd4b80c48 100644
--- a/Xi/exevents.c
+++ b/Xi/exevents.c
@@ -1223,9 +1223,13 @@ ProcessTouchOwnershipEvent(TouchOwnershipEvent *ev,
     else if (ev->reason == XIAcceptTouch) {
         int i;
 
-        /* Go through the motions of ending the touch if the listener has
+
+        /* For pointer-emulated listeners that ungrabbed the active grab,
+         * the state was forced to LISTENER_HAS_END. Still go
+         * through the motions of ending the touch if the listener has
          * already seen the end. This ensures that the touch record is ended in
-         * the server. */
+         * the server.
+         */
         if (ti->listeners[0].state == LISTENER_HAS_END)
             TouchEmitTouchEnd(dev, ti, TOUCH_ACCEPT, ti->listeners[0].listener);
 
@@ -1883,16 +1887,23 @@ DeliverTouchEndEvent(DeviceIntPtr dev, TouchPointInfoPtr ti, InternalEvent *ev,
 
     if (listener->type == LISTENER_POINTER_REGULAR ||
         listener->type == LISTENER_POINTER_GRAB) {
-        rc = DeliverTouchEmulatedEvent(dev, ti, ev, listener, client, win,
-                                       grab, xi2mask);
-
-         /* Once we send a TouchEnd to a legacy listener, we're already well
-          * past the accepting/rejecting stage (can only happen on
-          * GrabModeSync + replay. This listener now gets the end event,
-          * and we can continue.
-          */
-        if (rc == Success)
-            listener->state = LISTENER_HAS_END;
+        /* Note: If the active grab was ungrabbed, we already changed the
+         * state to LISTENER_HAS_END but still get here. So we mustn't
+         * actually send the event.
+         * This is part two of the hack in DeactivatePointerGrab
+         */
+        if (listener->state != LISTENER_HAS_END) {
+            rc = DeliverTouchEmulatedEvent(dev, ti, ev, listener, client, win,
+                                           grab, xi2mask);
+
+             /* Once we send a TouchEnd to a legacy listener, we're already well
+              * past the accepting/rejecting stage (can only happen on
+              * GrabModeSync + replay. This listener now gets the end event,
+              * and we can continue.
+              */
+            if (rc == Success)
+                listener->state = LISTENER_HAS_END;
+        }
         goto out;
     }