[clutter/wip/correct-opacity: 4/8] clutter-actor-meta: Add an internal 'priority' property

[Neil Roberts <nroberts src gnome org>]

commit 8e05f74d83b7b38d604dad34662e8c1310221b14
Author: Neil Roberts <neil linux intel com>
Date:   Tue Mar 1 15:37:04 2011 +0000

    clutter-actor-meta: Add an internal 'priority' property
    
    This adds a priority property to all ClutterActorMetas. The
    ClutterMetaGroup keeps the list sorted so that higher priority metas
    remain at the beginning of the list. The priority is a signed integer
    with the default as zero. An actor meta can therefore be put before
    all default metas with a positive number, or after with a negative
    number.
    
    There are constants to set an 'internal' priority. The intention is
    that applications wouldn't be allowed to use these values so that we
    can keep special internal metas to that are before or after all
    application metas.
    
    The property isn't a real GObject property because for now it is
    completely internal and only used to implement the 'transparency'
    property of ClutterActor. ClutterMetaGroup doesn't currently resort
    the list if the property changes so if we wanted to make it public we
    should either make it construct-only or make the meta group listen for
    changes on the property and resort accordingly.
    
    The methods in ClutterActor that get the list of metas now use a new
    function that filters out internal metas from the meta
    group. Similarly for clearing the metas, the internal metas are left
    in.

 clutter/clutter-actor-meta-private.h |   26 ++++++++
 clutter/clutter-actor-meta.c         |  117 +++++++++++++++++++++++++++++++++-
 clutter/clutter-actor.c              |   23 ++-----
 3 files changed, 148 insertions(+), 18 deletions(-)
---
diff --git a/clutter/clutter-actor-meta-private.h b/clutter/clutter-actor-meta-private.h
index 39c7626..e4d7731 100644
--- a/clutter/clutter-actor-meta-private.h
+++ b/clutter/clutter-actor-meta-private.h
@@ -50,6 +50,20 @@ struct _ClutterMetaGroupClass
   GObjectClass parent_class;
 };
 
+/* Each actor meta has a priority with zero as a default. A higher
+   number means higher priority. Higher priority metas stay at the
+   beginning of the list. The priority can be negative to give lower
+   priority than the default. */
+
+#define CLUTTER_ACTOR_META_PRIORITY_DEFAULT 0
+
+/* Any value greater than this is considered an 'internal' priority
+   and if we expose the priority property publicly then an application
+   would not be able to use these values. */
+
+#define CLUTTER_ACTOR_META_PRIORITY_INTERNAL_HIGH (G_MAXINT / 2)
+#define CLUTTER_ACTOR_META_PRIORITY_INTERNAL_LOW (G_MININT / 2)
+
 GType _clutter_meta_group_get_type (void) G_GNUC_CONST;
 
 void                  _clutter_meta_group_add_meta    (ClutterMetaGroup *group,
@@ -61,12 +75,24 @@ void                  _clutter_meta_group_clear_metas (ClutterMetaGroup *group);
 ClutterActorMeta *    _clutter_meta_group_get_meta    (ClutterMetaGroup *group,
                                                        const gchar      *name);
 
+GList *
+_clutter_meta_group_get_metas_no_internal (ClutterMetaGroup *group);
+
+void
+_clutter_meta_group_clear_metas_no_internal (ClutterMetaGroup *group);
+
 /* ActorMeta */
 void                  _clutter_actor_meta_set_actor   (ClutterActorMeta *meta,
                                                        ClutterActor     *actor);
 
 const gchar *           _clutter_actor_meta_get_debug_name        (ClutterActorMeta *meta);
 
+void                  _clutter_actor_meta_set_priority (ClutterActorMeta *meta,
+                                                        gint priority);
+int                   _clutter_actor_meta_get_priority (ClutterActorMeta *meta);
+
+gboolean              _clutter_actor_meta_is_internal  (ClutterActorMeta *meta);
+
 G_END_DECLS
 
 #endif /* __CLUTTER_ACTOR_META_PRIVATE_H__ */
diff --git a/clutter/clutter-actor-meta.c b/clutter/clutter-actor-meta.c
index e2ebdaa..68f8560 100644
--- a/clutter/clutter-actor-meta.c
+++ b/clutter/clutter-actor-meta.c
@@ -58,6 +58,8 @@ struct _ClutterActorMetaPrivate
   gchar *name;
 
   guint is_enabled : 1;
+
+  gint priority;
 };
 
 enum
@@ -237,6 +239,8 @@ clutter_actor_meta_init (ClutterActorMeta *self)
                                             ClutterActorMetaPrivate);
 
   self->priv->is_enabled = TRUE;
+
+  self->priv->priority = CLUTTER_ACTOR_META_PRIORITY_DEFAULT;
 }
 
 /**
@@ -367,6 +371,40 @@ clutter_actor_meta_get_actor (ClutterActorMeta *meta)
   return meta->priv->actor;
 }
 
+void
+_clutter_actor_meta_set_priority (ClutterActorMeta *meta,
+                                  gint priority)
+{
+  g_return_if_fail (CLUTTER_IS_ACTOR_META (meta));
+
+  /* This property shouldn't be modified after the actor meta is in
+     use because ClutterMetaGroup doesn't resort the list when it
+     changes. If we made the priority public then we could either make
+     the priority a construct-only property or listen for
+     notifications on the property from the ClutterMetaGroup and
+     resort. */
+  g_return_if_fail (meta->priv->actor == NULL);
+
+  meta->priv->priority = priority;
+}
+
+gint
+_clutter_actor_meta_get_priority (ClutterActorMeta *meta)
+{
+  g_return_val_if_fail (CLUTTER_IS_ACTOR_META (meta), 0);
+
+  return meta->priv->priority;
+}
+
+gboolean
+_clutter_actor_meta_is_internal (ClutterActorMeta *meta)
+{
+  gint priority = meta->priv->priority;
+
+  return (priority <= CLUTTER_ACTOR_META_PRIORITY_INTERNAL_LOW ||
+          priority >= CLUTTER_ACTOR_META_PRIORITY_INTERNAL_HIGH);
+}
+
 /*
  * ClutterMetaGroup: a collection of ClutterActorMeta instances
  */
@@ -408,6 +446,8 @@ void
 _clutter_meta_group_add_meta (ClutterMetaGroup *group,
                               ClutterActorMeta *meta)
 {
+  GList *prev = NULL, *l;
+
   if (meta->priv->actor != NULL)
     {
       g_warning ("The meta of type '%s' with name '%s' is "
@@ -422,7 +462,22 @@ _clutter_meta_group_add_meta (ClutterMetaGroup *group,
       return;
     }
 
-  group->meta = g_list_append (group->meta, meta);
+  /* Find a meta that has lower priority and insert before that */
+  for (l = group->meta; l; l = l->next)
+    if (_clutter_actor_meta_get_priority (l->data) <
+        _clutter_actor_meta_get_priority (meta))
+      break;
+    else
+      prev = l;
+
+  if (prev == NULL)
+    group->meta = g_list_prepend (group->meta, meta);
+  else
+    {
+      prev->next = g_list_prepend (prev->next, meta);
+      prev->next->prev = prev;
+    }
+
   g_object_ref_sink (meta);
 
   _clutter_actor_meta_set_actor (meta, group->actor);
@@ -474,6 +529,30 @@ _clutter_meta_group_peek_metas (ClutterMetaGroup *group)
 }
 
 /*
+ * _clutter_meta_group_get_metas_no_internal:
+ * @group: a #ClutterMetaGroup
+ *
+ * Returns a new allocated list containing all of the metas that don't
+ * have an internal priority.
+ *
+ * Return value: A GList containing non-internal metas. Free with
+ * g_list_free.
+ */
+GList *
+_clutter_meta_group_get_metas_no_internal (ClutterMetaGroup *group)
+{
+  GList *ret = NULL;
+  GList *l;
+
+  /* Build a new list filtering out the internal metas */
+  for (l = group->meta; l; l = l->next)
+    if (!_clutter_actor_meta_is_internal (l->data))
+      ret = g_list_prepend (ret, l->data);
+
+  return g_list_reverse (ret);
+}
+
+/*
  * _clutter_meta_group_clear_metas:
  * @group: a #ClutterMetaGroup
  *
@@ -491,6 +570,42 @@ _clutter_meta_group_clear_metas (ClutterMetaGroup *group)
 }
 
 /*
+ * _clutter_meta_group_clear_metas_no_internal:
+ * @group: a #ClutterMetaGroup
+ *
+ * Clears @group of all #ClutterActorMeta instances that don't have an
+ * internal priority and releases the reference on them
+ */
+void
+_clutter_meta_group_clear_metas_no_internal (ClutterMetaGroup *group)
+{
+  GList *internal_list = NULL;
+  GList *l, *next;
+
+  for (l = group->meta; l; l = next)
+    {
+      next = l->next;
+
+      if (_clutter_actor_meta_is_internal (l->data))
+        {
+          if (internal_list)
+            internal_list->prev = l;
+          l->next = internal_list;
+          l->prev = NULL;
+          internal_list = l;
+        }
+      else
+        {
+          _clutter_actor_meta_set_actor (l->data, NULL);
+          g_object_unref (l->data);
+          g_list_free_1 (l);
+        }
+    }
+
+  group->meta = g_list_reverse (internal_list);
+}
+
+/*
  * _clutter_meta_group_get_meta:
  * @group: a #ClutterMetaGroup
  * @name: the name of the #ClutterActorMeta to retrieve
diff --git a/clutter/clutter-actor.c b/clutter/clutter-actor.c
index 59e97ff..5163914 100644
--- a/clutter/clutter-actor.c
+++ b/clutter/clutter-actor.c
@@ -11268,16 +11268,12 @@ clutter_actor_remove_action_by_name (ClutterActor *self,
 GList *
 clutter_actor_get_actions (ClutterActor *self)
 {
-  const GList *actions;
-
   g_return_val_if_fail (CLUTTER_IS_ACTOR (self), NULL);
 
   if (self->priv->actions == NULL)
     return NULL;
 
-  actions = _clutter_meta_group_peek_metas (self->priv->actions);
-
-  return g_list_copy ((GList *) actions);
+  return _clutter_meta_group_get_metas_no_internal (self->priv->actions);
 }
 
 /**
@@ -11323,7 +11319,7 @@ clutter_actor_clear_actions (ClutterActor *self)
   if (self->priv->actions == NULL)
     return;
 
-  _clutter_meta_group_clear_metas (self->priv->actions);
+  _clutter_meta_group_clear_metas_no_internal (self->priv->actions);
 }
 
 /**
@@ -11476,16 +11472,12 @@ clutter_actor_remove_constraint_by_name (ClutterActor *self,
 GList *
 clutter_actor_get_constraints (ClutterActor *self)
 {
-  const GList *constraints;
-
   g_return_val_if_fail (CLUTTER_IS_ACTOR (self), NULL);
 
   if (self->priv->constraints == NULL)
     return NULL;
 
-  constraints = _clutter_meta_group_peek_metas (self->priv->constraints);
-
-  return g_list_copy ((GList *) constraints);
+  return _clutter_meta_group_get_metas_no_internal (self->priv->constraints);
 }
 
 /**
@@ -11531,7 +11523,7 @@ clutter_actor_clear_constraints (ClutterActor *self)
   if (self->priv->constraints == NULL)
     return;
 
-  _clutter_meta_group_clear_metas (self->priv->constraints);
+  _clutter_meta_group_clear_metas_no_internal (self->priv->constraints);
 }
 
 /**
@@ -11733,7 +11725,6 @@ GList *
 clutter_actor_get_effects (ClutterActor *self)
 {
   ClutterActorPrivate *priv;
-  const GList *effects;
 
   g_return_val_if_fail (CLUTTER_IS_ACTOR (self), NULL);
 
@@ -11742,9 +11733,7 @@ clutter_actor_get_effects (ClutterActor *self)
   if (priv->effects == NULL)
     return NULL;
 
-  effects = _clutter_meta_group_peek_metas (priv->effects);
-
-  return g_list_copy ((GList *) effects);
+  return _clutter_meta_group_get_metas_no_internal (priv->effects);
 }
 
 /**
@@ -11790,7 +11779,7 @@ clutter_actor_clear_effects (ClutterActor *self)
   if (self->priv->effects == NULL)
     return;
 
-  _clutter_meta_group_clear_metas (self->priv->effects);
+  _clutter_meta_group_clear_metas_no_internal (self->priv->effects);
 }
 
 /**