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

[Peter Hutterer]

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 at who-t.net>
---
 Xi/exevents.c | 33 ++++++++++++++++++++++-----------
 dix/events.c  | 11 +++++++++--
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/Xi/exevents.c b/Xi/exevents.c
index 2bbc6f0..fd4b80c 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);
+        /* 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;
+             /* 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;
     }
 
diff --git a/dix/events.c b/dix/events.c
index e5db348..03b2d2e 100644
--- a/dix/events.c
+++ b/dix/events.c
@@ -1522,13 +1522,20 @@ DeactivatePointerGrab(DeviceIntPtr mouse)
     for (i = 0; !wasPassive && mouse->touch && i < mouse->touch->num_touches; i++) {
         TouchPointInfoPtr ti = mouse->touch->touches + i;
         if (ti->active && TouchResourceIsOwner(ti, grab_resource)) {
+            int mode = XIRejectTouch;
             /* Rejecting will generate a TouchEnd, but we must not
                emulate a ButtonRelease here. So pretend the listener
                already has the end event */
             if (grab->grabtype == CORE || grab->grabtype == XI ||
-                    !xi2mask_isset(mouse->deviceGrab.grab->xi2mask, mouse, XI_TouchBegin))
+                    !xi2mask_isset(mouse->deviceGrab.grab->xi2mask, mouse, XI_TouchBegin)) {
+                mode = XIAcceptTouch;
+                /* NOTE: we set the state here, but
+                 * ProcessTouchOwnershipEvent() will still call
+                 * TouchEmitTouchEnd for this listener. The other half of
+                 * this hack is in DeliverTouchEndEvent */
                 ti->listeners[0].state = LISTENER_HAS_END;
-            TouchListenerAcceptReject(mouse, ti, 0, XIRejectTouch);
+            }
+            TouchListenerAcceptReject(mouse, ti, 0, mode);
         }
     }
 
-- 
1.8.2.1