[mutter/wip/texture-purge-on-nvidia: 50/71] clutter: Keep a device reference with events

[Ray Strode <halfline src gnome org>]

commit ab395585061d2622ecda8900c8278ed3eecc34d7
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Mon Nov 19 11:25:57 2018 +0100

    clutter: Keep a device reference with events
    
    If a device (virtual or real) is removed while there are remaining
    events queued for that device, the event loop may try to access the
    event freed memory.
    
    To avoid the issue, add a reference to the device when the event is
    created or copied, and remove the reference once the device is freed.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/issues/393

 clutter/clutter/clutter-event.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)
---
diff --git a/clutter/clutter/clutter-event.c b/clutter/clutter/clutter-event.c
index 10b6c0082..1b21b6a97 100644
--- a/clutter/clutter/clutter-event.c
+++ b/clutter/clutter/clutter-event.c
@@ -1095,7 +1095,7 @@ clutter_event_set_device (ClutterEvent       *event,
     {
       ClutterEventPrivate *real_event = (ClutterEventPrivate *) event;
 
-      real_event->device = device;
+      g_set_object (&real_event->device, device);
     }
 
   switch (event->type)
@@ -1364,8 +1364,8 @@ clutter_event_copy (const ClutterEvent *event)
     {
       ClutterEventPrivate *real_event = (ClutterEventPrivate *) event;
 
-      new_real_event->device = real_event->device;
-      new_real_event->source_device = real_event->source_device;
+      g_set_object (&new_real_event->device, real_event->device);
+      g_set_object (&new_real_event->source_device, real_event->source_device);
       new_real_event->delta_x = real_event->delta_x;
       new_real_event->delta_y = real_event->delta_y;
       new_real_event->is_pointer_emulated = real_event->is_pointer_emulated;
@@ -1435,6 +1435,14 @@ clutter_event_free (ClutterEvent *event)
     {
       _clutter_backend_free_event_data (clutter_get_default_backend (), event);
 
+      if (is_event_allocated (event))
+        {
+          ClutterEventPrivate *real_event = (ClutterEventPrivate *) event;
+
+          g_clear_object (&real_event->device);
+          g_clear_object (&real_event->source_device);
+        }
+
       switch (event->type)
         {
         case CLUTTER_BUTTON_PRESS:
@@ -1689,7 +1697,7 @@ clutter_event_set_source_device (ClutterEvent       *event,
     return;
 
   real_event = (ClutterEventPrivate *) event;
-  real_event->source_device = device;
+  g_set_object (&real_event->source_device, device);
 }
 
 /**