st-texture-cache: Deduplicate async URI requests

More than one outstanding request to the same URI should now be
deduplicated, and the framework is there if we want to cache async loaded
URIs as well

https://bugzilla.gnome.org/show_bug.cgi?id=672273

src/st/st-texture-cache.c

@@ -38,10 +38,8 @@ struct _StTextureCachePrivate
 
   /* Things that were loaded with a cache policy != NONE */
   GHashTable *keyed_cache; /* char * -> CoglTexture* */
-  /* Presently this is used to de-duplicate requests for GIcons,
-   * it could in theory be extended to async URL loading and other
-   * cases too.
-   */
+
+  /* Presently this is used to de-duplicate requests for GIcons and async URIs. */
   GHashTable *outstanding_requests; /* char * -> AsyncTextureLoadData * */
 };
 
@@ -833,13 +831,12 @@ st_texture_cache_load (StTextureCache       *cache,
 }
 
 /**
- * create_texture_and_ensure_request:
+ * ensure_request:
  * @cache:
  * @key: A cache key
- * @size: Size in pixels
  * @policy: Cache policy
  * @request: (out): If no request is outstanding, one will be created and returned here
- * @texture: (out): A new texture, also added to the request
+ * @texture: A texture to be added to the request
  *
  * Check for any outstanding load for the data represented by @key.  If there
  * is already a request pending, append it to that request to avoid loading
@@ -848,26 +845,22 @@ st_texture_cache_load (StTextureCache       *cache,
  * Returns: %TRUE iff there is already a request pending
  */
 static gboolean
-create_texture_and_ensure_request (StTextureCache        *cache,
-                                   const char            *key,
-                                   guint                  size,
-                                   StTextureCachePolicy   policy,
-                                   AsyncTextureLoadData **request,
-                                   ClutterActor         **texture)
+ensure_request (StTextureCache        *cache,
+                const char            *key,
+                StTextureCachePolicy   policy,
+                AsyncTextureLoadData **request,
+                ClutterActor          *texture)
 {
   CoglHandle texdata;
   AsyncTextureLoadData *pending;
   gboolean had_pending;
 
-  *texture = (ClutterActor *) create_default_texture ();
-  clutter_actor_set_size (*texture, size, size);
-
   texdata = g_hash_table_lookup (cache->priv->keyed_cache, key);
 
   if (texdata != NULL)
     {
       /* We had this cached already, just set the texture and we're done. */
-      set_texture_cogl_texture (CLUTTER_TEXTURE (*texture), texdata);
+      set_texture_cogl_texture (CLUTTER_TEXTURE (texture), texdata);
       return TRUE;
     }
 
@@ -885,7 +878,7 @@ create_texture_and_ensure_request (StTextureCache        *cache,
    *request = pending;
 
   /* Regardless of whether there was a pending request, prepend our texture here. */
-  (*request)->textures = g_slist_prepend ((*request)->textures, g_object_ref (*texture));
+  (*request)->textures = g_slist_prepend ((*request)->textures, g_object_ref (texture));
 
   return had_pending;
 }
@@ -935,7 +928,10 @@ load_gicon_with_colors (StTextureCache    *cache,
     }
   g_free (gicon_string);
 
-  if (create_texture_and_ensure_request (cache, key, size, policy, &request, &texture))
+  texture = (ClutterActor *) create_default_texture ();
+  clutter_actor_set_size (texture, size, size);
+
+  if (ensure_request (cache, key, policy, &request, texture))
     {
       /* If there's an outstanding request, we've just added ourselves to it */
       g_free (key);
@@ -1263,20 +1259,36 @@ st_texture_cache_load_uri_async (StTextureCache *cache,
                                  int             available_width,
                                  int             available_height)
 {
-  ClutterTexture *texture;
-  AsyncTextureLoadData *data;
+  ClutterActor *texture;
+  AsyncTextureLoadData *request;
+  StTextureCachePolicy policy;
+  gchar *key;
 
-  texture = create_default_texture ();
+  key = g_strconcat (CACHE_PREFIX_URI, uri, NULL);
 
-  data = g_new0 (AsyncTextureLoadData, 1);
-  data->cache = cache;
-  data->key = g_strconcat (CACHE_PREFIX_URI, uri, NULL);
-  data->policy = ST_TEXTURE_CACHE_POLICY_NONE;
-  data->uri = g_strdup (uri);
-  data->width = available_width;
-  data->height = available_height;
-  data->textures = g_slist_prepend (data->textures, g_object_ref (texture));
-  load_texture_async (cache, data);
+  policy = ST_TEXTURE_CACHE_POLICY_NONE; /* XXX */
+
+  texture = (ClutterActor *) create_default_texture ();
+
+  if (ensure_request (cache, key, policy, &request, texture))
+    {
+      /* If there's an outstanding request, we've just added ourselves to it */
+      g_free (key);
+    }
+  else
+    {
+      /* Else, make a new request */
+
+      request->cache = cache;
+      /* Transfer ownership of key */
+      request->key = key;
+      request->uri = g_strdup (uri);
+      request->policy = policy;
+      request->width = available_width;
+      request->height = available_height;
+
+      load_texture_async (cache, request);
+    }
 
   return CLUTTER_ACTOR (texture);
 }