[mutter] window-actor: add new signal "effects-completed"

[Olivier Fourdan <ofourdan src gnome org>]

commit 85bbd82ae847eed0bba943c119a356d9493f7da2
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Wed Apr 4 10:10:32 2018 +0200

    window-actor: add new signal "effects-completed"
    
    When using plugins, the effects will affect the MetaWindowActor size
    and position.
    
    Add a new signal "effects-completed" wired to the corresponding
    MetaWindowActor which is emitted when all effects are completed so that
    derived objects can be notified when all effects are completed and use
    the actual size and position.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/issues/104

 src/compositor/meta-window-actor-private.h |  1 +
 src/compositor/meta-window-actor.c         | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)
---
diff --git a/src/compositor/meta-window-actor-private.h b/src/compositor/meta-window-actor-private.h
index 6b52ef5b5..ce5e7eadc 100644
--- a/src/compositor/meta-window-actor-private.h
+++ b/src/compositor/meta-window-actor-private.h
@@ -58,5 +58,6 @@ void meta_window_actor_effect_completed (MetaWindowActor  *actor,
 
 MetaSurfaceActor *meta_window_actor_get_surface (MetaWindowActor *self);
 void meta_window_actor_update_surface (MetaWindowActor *self);
+MetaWindowActor *meta_window_actor_from_window (MetaWindow *window);
 
 #endif /* META_WINDOW_ACTOR_PRIVATE_H */
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index c67b2b7b0..5078624cc 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -142,6 +142,8 @@ struct _FrameData
 enum
 {
   FIRST_FRAME,
+  EFFECTS_COMPLETED,
+
   LAST_SIGNAL
 };
 
@@ -238,6 +240,21 @@ meta_window_actor_class_init (MetaWindowActorClass *klass)
                   NULL, NULL, NULL,
                   G_TYPE_NONE, 0);
 
+  /**
+   * MetaWindowActor::effects-completed:
+   * @actor: the #MetaWindowActor instance
+   *
+   * The ::effects-completed signal will be emitted once all pending compositor
+   * effects are completed.
+   */
+  signals[EFFECTS_COMPLETED] =
+    g_signal_new ("effects-completed",
+                  G_TYPE_FROM_CLASS (object_class),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 0);
+
   pspec = g_param_spec_object ("meta-window",
                                "MetaWindow",
                                "The displayed MetaWindow",
@@ -1131,6 +1148,7 @@ meta_window_actor_after_effects (MetaWindowActor *self)
       return;
     }
 
+  g_signal_emit (self, signals[EFFECTS_COMPLETED], 0);
   meta_window_actor_sync_visibility (self);
   meta_window_actor_sync_actor_geometry (self, FALSE);
 }
@@ -2157,3 +2175,9 @@ meta_window_actor_sync_updates_frozen (MetaWindowActor *self)
 
   meta_window_actor_set_updates_frozen (self, meta_window_updates_are_frozen (window));
 }
+
+MetaWindowActor *
+meta_window_actor_from_window (MetaWindow *window)
+{
+  return META_WINDOW_ACTOR (meta_window_get_compositor_private (window));
+}