[grilo] core: Preload available plugins' information

[Juan A. Suarez Romero <jasuarez src gnome org>]

commit 46948e96e4e8c7f411ab42f565020644a52e2762
Author: Juan A. Suarez Romero <jasuarez igalia com>
Date:   Fri Apr 8 15:07:21 2011 +0000

    core: Preload available plugins' information
    
    When initializing Grilo, load all plugins information stored in XML files.
    
    This will allow to know in advance what are the plugins available in the
    system.
    
    Signed-off-by: Juan A. Suarez Romero <jasuarez igalia com>

 src/grl-plugin-registry.c |  112 +++++++++++++++++++++++++++++++++-----------
 src/grl-plugin-registry.h |    6 +-
 2 files changed, 87 insertions(+), 31 deletions(-)
---
diff --git a/src/grl-plugin-registry.c b/src/grl-plugin-registry.c
index 93f6786..9d53373 100644
--- a/src/grl-plugin-registry.c
+++ b/src/grl-plugin-registry.c
@@ -52,6 +52,8 @@ GRL_LOG_DOMAIN(plugin_registry_log_domain);
 
 #define XML_ROOT_ELEMENT_NAME "plugin"
 
+#define GRL_PLUGIN_INFO_SUFFIX "xml"
+
 #define GRL_PLUGIN_REGISTRY_GET_PRIVATE(object)                 \
   (G_TYPE_INSTANCE_GET_PRIVATE((object),                        \
                                GRL_TYPE_PLUGIN_REGISTRY,        \
@@ -60,6 +62,7 @@ GRL_LOG_DOMAIN(plugin_registry_log_domain);
 struct _GrlPluginRegistryPrivate {
   GHashTable *configs;
   GHashTable *plugins;
+  GHashTable *plugin_infos;
   GHashTable *sources;
   GHashTable *related_keys;
   GParamSpecPool *system_keys;
@@ -68,6 +71,7 @@ struct _GrlPluginRegistryPrivate {
 };
 
 static void grl_plugin_registry_setup_ranks (GrlPluginRegistry *registry);
+static void grl_plugin_registry_load_plugin_infos (GrlPluginRegistry *registry);
 
 /* ================ GrlPluginRegistry GObject ================ */
 
@@ -129,6 +133,8 @@ grl_plugin_registry_init (GrlPluginRegistry *registry)
     g_hash_table_new_full (g_str_hash, g_str_equal, NULL, g_object_unref);
   registry->priv->plugins =
     g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
+  registry->priv->plugin_infos =
+    g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
   registry->priv->sources =
     g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
   registry->priv->related_keys =
@@ -137,6 +143,7 @@ grl_plugin_registry_init (GrlPluginRegistry *registry)
     g_param_spec_pool_new (FALSE);
 
   grl_plugin_registry_setup_ranks (registry);
+  grl_plugin_registry_load_plugin_infos (registry);
 }
 
 /* ================ Utitilies ================ */
@@ -153,15 +160,15 @@ config_plugin_rank (GrlPluginRegistry *registry,
 }
 
 static void
-set_plugin_rank (GrlPluginRegistry *registry, GrlPluginDescriptor *plugin)
+set_plugin_rank (GrlPluginRegistry *registry, GrlPluginInfo *info)
 {
-  plugin->info.rank =
+  info->rank =
     GPOINTER_TO_INT (g_hash_table_lookup (registry->priv->ranks,
-					  plugin->info.id));
-  if (!plugin->info.rank) {
-    plugin->info.rank = GRL_PLUGIN_RANK_DEFAULT;
+					  info->id));
+  if (!info->rank) {
+    info->rank = GRL_PLUGIN_RANK_DEFAULT;
   }
-  GRL_DEBUG ("Plugin rank '%s' : %d", plugin->info.id, plugin->info.rank);
+  GRL_DEBUG ("Plugin rank '%s' : %d", info->id, info->rank);
 }
 
 static void
@@ -266,6 +273,45 @@ get_info_from_plugin_xml (const gchar *xml_path)
   return hash_table;
 }
 
+static void
+grl_plugin_registry_load_plugin_infos (GrlPluginRegistry *registry)
+{
+  GDir *dir;
+  GError *error = NULL;
+  GHashTable *info;
+  GrlPluginInfo *plugin_info;
+  const gchar *entry;
+  gchar *file;
+  gchar *suffix;
+
+  dir = g_dir_open (GRL_PLUGINS_CONF_DIR, 0, &error);
+  if (!dir) {
+    GRL_WARNING ("Could not open plugins' info directory '%s': %s",
+                 GRL_PLUGINS_CONF_DIR,
+                 error->message);
+    g_error_free (error);
+    return;
+  }
+
+  while ((entry = g_dir_read_name (dir)) != NULL) {
+    if ((suffix = g_strrstr (entry, "." GRL_PLUGIN_INFO_SUFFIX)) != NULL) {
+      file = g_build_filename (GRL_PLUGINS_CONF_DIR, entry, NULL);
+      info = get_info_from_plugin_xml (file);
+      g_free (file);
+      if (info) {
+        plugin_info = g_new0 (GrlPluginInfo, 1);
+        plugin_info->id = g_strndup (entry, suffix - entry);
+        plugin_info->optional_info = info;
+        g_hash_table_insert (registry->priv->plugin_infos,
+                             plugin_info->id,
+                             plugin_info);
+      }
+    }
+  }
+
+  g_dir_close (dir);
+}
+
 /* ================ API ================ */
 
 /**
@@ -418,8 +464,8 @@ grl_plugin_registry_load (GrlPluginRegistry *registry,
 {
   GModule *module;
   GrlPluginDescriptor *plugin;
+  GrlPluginInfo *plugin_info;
   GList *plugin_configs;
-  gchar *xml_path;
 
   g_return_val_if_fail (GRL_IS_PLUGIN_REGISTRY (registry), FALSE);
 
@@ -444,7 +490,7 @@ grl_plugin_registry_load (GrlPluginRegistry *registry,
   }
 
   if (!plugin->plugin_init ||
-      !plugin->info.id) {
+      !plugin->plugin_id) {
     GRL_WARNING ("Plugin descriptor is not valid: '%s'", path);
     g_set_error (error,
                  GRL_CORE_ERROR,
@@ -454,26 +500,39 @@ grl_plugin_registry_load (GrlPluginRegistry *registry,
     return FALSE;
   }
 
-  plugin->info.filename = g_strdup (path);
+  plugin_info = g_hash_table_lookup (registry->priv->plugin_infos,
+                                     plugin->plugin_id);
 
-  xml_path = g_strconcat (GRL_PLUGINS_CONF_DIR,
-			  G_DIR_SEPARATOR_S,
-			  plugin->info.id,
-			  ".xml",
-			  NULL);
-  plugin->info.optional_info =  get_info_from_plugin_xml (xml_path);
-  g_free (xml_path);
-
-  set_plugin_rank (registry, plugin);
+  if (!plugin_info) {
+    plugin_info = g_new0 (GrlPluginInfo, 1);
+    plugin_info->id = plugin->plugin_id;
+    g_hash_table_insert (registry->priv->plugin_infos,
+                         plugin_info->id,
+                         plugin_info);
+  }
 
+  set_plugin_rank (registry, plugin_info);
   g_hash_table_insert (registry->priv->plugins,
-		       (gpointer) plugin->info.id, plugin);
+                       (gpointer) plugin->plugin_id, plugin);
+
+  /* Plugin info can have a valid filename if the plugin was loaded previously
+     (and unloaded afterwards). Note that we do not free filename when plugin is
+     unloaded because this way, if user tries to load the plugin with
+     load_by_id(), it will not need to search for the plugin throughout the list
+     of plugin directories: filename will be already pointing to the right
+     filename */
+  if (plugin_info->filename) {
+    g_free (plugin_info->filename);
+  }
+  plugin_info->filename = g_strdup (path);
 
   plugin_configs = g_hash_table_lookup (registry->priv->configs,
-					plugin->info.id);
+					plugin->plugin_id);
 
-  if (!plugin->plugin_init (registry, &plugin->info, plugin_configs)) {
-    g_hash_table_remove (registry->priv->plugins, plugin->info.id);
+  if (!plugin->plugin_init (registry, plugin_info, plugin_configs)) {
+    g_free (plugin_info->filename);
+    plugin_info->filename = NULL;
+    g_hash_table_remove (registry->priv->plugins, plugin->plugin_id);
     GRL_WARNING ("Failed to initialize plugin: '%s'", path);
     g_set_error (error,
                  GRL_CORE_ERROR,
@@ -485,7 +544,7 @@ grl_plugin_registry_load (GrlPluginRegistry *registry,
 
   plugin->module = module;
 
-  GRL_DEBUG ("Loaded plugin '%s' from '%s'", plugin->info.id, path);
+  GRL_DEBUG ("Loaded plugin '%s' from '%s'", plugin->plugin_id, path);
 
   return TRUE;
 }
@@ -751,15 +810,12 @@ grl_plugin_registry_unload (GrlPluginRegistry *registry,
     plugin->plugin_deinit ();
   }
 
-  g_free (plugin->info.filename);
-  if (plugin->info.optional_info) {
-    g_hash_table_destroy (plugin->info.optional_info);
-  }
-
   if (plugin->module) {
     g_module_close (plugin->module);
   }
 
+  g_hash_table_remove (registry->priv->plugins, plugin_id);
+
   return TRUE;
 }
 
diff --git a/src/grl-plugin-registry.h b/src/grl-plugin-registry.h
index d8257b1..abe473c 100644
--- a/src/grl-plugin-registry.h
+++ b/src/grl-plugin-registry.h
@@ -83,7 +83,7 @@
                             deinit,             \
                             id)			\
   G_MODULE_EXPORT GrlPluginDescriptor GRL_PLUGIN_DESCRIPTOR = {		\
-    .info = { id, NULL, NULL, 0 },					\
+    .plugin_id = id,                                                    \
     .plugin_init = init,						\
     .plugin_deinit = deinit,						\
     .module = NULL							\
@@ -119,7 +119,7 @@ typedef struct _GrlPluginDescriptor  GrlPluginDescriptor;
 
 /**
 * GrlPluginDescriptor:
-* @info: the module information
+* @id: the module identifier
 * @plugin_init: the module initialization. It shall instantiate
 * the #GrlMediaPlugins provided
 * @plugin_deinit: function to execute when the registry needs
@@ -129,7 +129,7 @@ typedef struct _GrlPluginDescriptor  GrlPluginDescriptor;
 * This structure is used for the module loader
 */
 struct _GrlPluginDescriptor {
-  GrlPluginInfo info;
+  gchar *plugin_id;
   gboolean (*plugin_init) (GrlPluginRegistry *, const GrlPluginInfo *, GList *);
   void (*plugin_deinit) (void);
   GModule *module;