Avoid needless event copies when queueing from a backend to a stage

All backends follow the same pattern of queueing events first in
ClutterMainContext, then copying them to a ClutterStage queue and
immediately free them. Instead, we can just pass ownership of events
directly to ClutterStage thus avoiding the allocation and copy in
between.

https://bugzilla.gnome.org/show_bug.cgi?id=711857

clutter/clutter-main.c

@@ -2410,7 +2410,7 @@ clutter_do_event (ClutterEvent *event)
    * because we've "looked ahead" and know all motion events that
    * will occur before drawing the frame.
    */
-  _clutter_stage_queue_event (event->any.stage, event);
+  _clutter_stage_queue_event (event->any.stage, event, TRUE);
 }
 
 static void

clutter/clutter-stage-private.h

@@ -62,7 +62,8 @@ gboolean            _clutter_stage_needs_update          (ClutterStage
 gboolean            _clutter_stage_do_update             (ClutterStage          *stage);
 
 void     _clutter_stage_queue_event                       (ClutterStage *stage,
-					                   ClutterEvent *event);
+                                                           ClutterEvent *event,
+                                                           gboolean      copy_event);
 gboolean _clutter_stage_has_queued_events                 (ClutterStage *stage);
 void     _clutter_stage_process_queued_events             (ClutterStage *stage);
 void     _clutter_stage_update_input_devices              (ClutterStage *stage);

clutter/clutter-stage.c

@@ -937,7 +937,8 @@ clutter_stage_real_fullscreen (ClutterStage *stage)
 
 void
 _clutter_stage_queue_event (ClutterStage *stage,
-			    ClutterEvent *event)
+                            ClutterEvent *event,
+                            gboolean      copy_event)
 {
   ClutterStagePrivate *priv;
   gboolean first_event;
@@ -949,7 +950,10 @@ _clutter_stage_queue_event (ClutterStage *stage,
 
   first_event = priv->event_queue->length == 0;
 
-  g_queue_push_tail (priv->event_queue, clutter_event_copy (event));
+  if (copy_event)
+    event = clutter_event_copy (event);
+
+  g_queue_push_tail (priv->event_queue, event);
 
   if (first_event)
     {

clutter/evdev/clutter-device-manager-evdev.c

@@ -51,6 +51,7 @@
 #include "clutter-xkb-utils.h"
 #include "clutter-backend-private.h"
 #include "clutter-evdev.h"
+#include "clutter-stage-private.h"
 
 #include "clutter-device-manager-evdev.h"
 
@@ -573,8 +574,7 @@ clutter_event_dispatch (GSource     *g_source,
         goto out;
 
       /* forward the event into clutter for emission etc. */
-      clutter_do_event (event);
-      clutter_event_free (event);
+      _clutter_stage_queue_event (event->any.stage, event, FALSE);
 
       /* update the device states *after* the event */
       event_state = xkb_state_serialize_mods (seat->xkb, XKB_STATE_MODS_EFFECTIVE);

clutter/gdk/clutter-event-gdk.c

@@ -309,8 +309,7 @@ clutter_gdk_handle_event (GdkEvent *gdk_event)
       while (spin > 0 && (event = clutter_event_get ()))
 	{
 	  /* forward the event into clutter for emission etc. */
-	  clutter_do_event (event);
-	  clutter_event_free (event);
+          _clutter_stage_queue_event (event->any.stage, event, FALSE);
 	  --spin;
 	}
 

clutter/osx/clutter-event-loop-osx.c

@@ -712,8 +712,7 @@ clutter_event_dispatch (GSource     *source,
   if (event)
     {
       /* forward the event into clutter for emission etc. */
-      clutter_do_event (event);
-      clutter_event_free (event);
+      _clutter_stage_queue_event (event->any.stage, event, FALSE);
     }
 
   _clutter_threads_release_lock ();

clutter/tslib/clutter-event-tslib.c

@@ -267,8 +267,7 @@ clutter_event_dispatch (GSource     *source,
   if (event)
     {
       /* forward the event into clutter for emission etc. */
-      clutter_do_event (event);
-      clutter_event_free (event);
+      _clutter_stage_queue_event (event->any.stage, event, FALSE);
     }
 
 out:

clutter/wayland/clutter-event-wayland.c

@@ -35,6 +35,7 @@
 #include "clutter-event.h"
 #include "clutter-main.h"
 #include "clutter-private.h"
+#include "clutter-stage-private.h"
 
 #include "clutter-event-wayland.h"
 
@@ -94,8 +95,7 @@ clutter_event_source_wayland_dispatch (GSource *base,
   if (event)
     {
       /* forward the event into clutter for emission etc. */
-      clutter_do_event (event);
-      clutter_event_free (event);
+      _clutter_stage_queue_event (event->any.stage, event, FALSE);
     }
 
   _clutter_threads_release_lock ();

clutter/win32/clutter-event-win32.c

@@ -294,8 +294,7 @@ clutter_event_dispatch (GSource     *source,
   if ((event = clutter_event_get ()))
     {
       /* forward the event into clutter for emission etc. */
-      clutter_do_event (event);
-      clutter_event_free (event);
+      _clutter_stage_queue_event (event->any.stage, event, FALSE);
     }
 
   _clutter_threads_release_lock ();

clutter/x11/clutter-event-x11.c

@@ -34,6 +34,7 @@
 #include "clutter-event-private.h"
 #include "clutter-main.h"
 #include "clutter-private.h"
+#include "clutter-stage-private.h"
 
 #include <string.h>
 
@@ -220,8 +221,7 @@ clutter_x11_handle_event (XEvent *xevent)
   while (spin > 0 && (event = clutter_event_get ()))
     {
       /* forward the event into clutter for emission etc. */
-      clutter_do_event (event);
-      clutter_event_free (event);
+      _clutter_stage_queue_event (event->any.stage, event, FALSE);
       --spin;
     }
 
@@ -321,8 +321,7 @@ clutter_event_dispatch (GSource     *source,
   if (event != NULL)
     {
       /* forward the event into clutter for emission etc. */
-      clutter_do_event (event);
-      clutter_event_free (event);
+      _clutter_stage_queue_event (event->any.stage, event, FALSE);
     }
 
   _clutter_threads_release_lock ();