Migrating docs.

[platform/upstream/glib.git] / gobject / gtypeplugin.c

diff --git a/gobject/gtypeplugin.c b/gobject/gtypeplugin.c
index 2d681bd..8aaa7e4 100644 (file)
--- a/gobject/gtypeplugin.c
+++ b/gobject/gtypeplugin.c
@@ -16,6 +16,68 @@
  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  * Boston, MA 02111-1307, USA.
  */
+/**
+ * SECTION:gtypeplugin
+ * @Short_description: An interface for dynamically loadable types
+ * @See_also:#GTypeModule and g_type_register_dynamic().
+ * @Titile: GTypePlugin
+ * 
+ * The GObject type system supports dynamic loading of types. The #GTypePlugin 
+ * interface is used to handle the lifecycle of dynamically loaded types. 
+ * It goes as follows:
+ * 
+ * <orderedlist>
+ * <listitem><para>
+ *   The type is initially introduced (usually upon loading the module
+ *   the first time, or by your main application that knows what modules
+ *   introduces what types), like this:
+ *   |[
+ *   new_type_id = g_type_register_dynamic (parent_type_id,
+ *                                                 "TypeName",
+ *                                                 new_type_plugin,
+ *                                                 type_flags);
+ *   ]|
+ *   where <literal>new_type_plugin</literal> is an implementation of the
+ *   #GTypePlugin interface.
+ * </para></listitem>
+ * <listitem><para>
+ *    The type's implementation is referenced, e.g. through
+ *    g_type_class_ref() or through g_type_create_instance() (this is 
+ *    being called by g_object_new()) or through one of the above done on 
+ *    a type derived from <literal>new_type_id</literal>.
+ * </para></listitem>
+ * <listitem><para>
+ *    This causes the type system to load the type's implementation by calling
+ *    g_type_plugin_use() and g_type_plugin_complete_type_info() on 
+ *    <literal>new_type_plugin</literal>.
+ * </para></listitem>
+ * <listitem><para>
+ *    At some point the type's implementation isn't required anymore, e.g. after
+ *    g_type_class_unref() or g_type_free_instance() (called when the reference
+ *    count of an instance drops to zero).
+ * </para></listitem>
+ * <listitem><para>
+ *    This causes the type system to throw away the information retrieved from
+ *    g_type_plugin_complete_type_info() and then it calls
+ *    g_type_plugin_unuse() on <literal>new_type_plugin</literal>.
+ * </para></listitem>
+ * <listitem><para>
+ *    Things may repeat from the second step.
+ * </para></listitem>
+ * </orderedlist>
+ * 
+ * So basically, you need to implement a #GTypePlugin type that carries a
+ * use_count, once use_count goes from zero to one, you need to load the 
+ * implementation to successfully handle the upcoming 
+ * g_type_plugin_complete_type_info() call. Later, maybe after succeeding 
+ * use/unuse calls, once use_count drops to zero, you can unload the 
+ * implementation again. The type system makes sure to call g_type_plugin_use() 
+ * and g_type_plugin_complete_type_info() again when the type is needed again.
+ * 
+ * #GTypeModule is an implementation of #GTypePlugin that already implements 
+ * most of this except for the actual module loading and unloading. It even 
+ * handles multiple registered types per module.
+ */
 #include       "gtypeplugin.h"
 #include       "gobjectalias.h"
 
@@ -41,6 +103,14 @@ g_type_plugin_get_type (void)
   return type_plugin_type;
 }
 
+/**
+ * g_type_plugin_use:
+ * @plugin: a #GTypePlugin
+ * 
+ * Calls the @use_plugin function from the #GTypePluginClass of @plugin.
+ * There should be no need to use this function outside of the GObject 
+ * type system itself.
+ */
 void
 g_type_plugin_use (GTypePlugin *plugin)
 {
@@ -52,6 +122,14 @@ g_type_plugin_use (GTypePlugin *plugin)
   iface->use_plugin (plugin);
 }
 
+/**
+ * g_type_plugin_unuse:
+ * @plugin: a #GTypePlugin
+ * 
+ * Calls the @unuse_plugin function from the #GTypePluginClass of @plugin.
+ * There should be no need to use this function outside of the GObject 
+ * type system itself.
+ */
 void
 g_type_plugin_unuse (GTypePlugin *plugin)
 {
@@ -63,6 +141,17 @@ g_type_plugin_unuse (GTypePlugin *plugin)
   iface->unuse_plugin (plugin);
 }
 
+/**
+ * g_type_plugin_complete_type_info:
+ * @plugin: a #GTypePlugin
+ * @g_type: the #GType whose info is completed
+ * @info: the #GTypeInfo struct to fill in
+ * @value_table: the #GTypeValueTable to fill in
+ * 
+ * Calls the @complete_type_info function from the #GTypePluginClass of @plugin.
+ * There should be no need to use this function outside of the GObject 
+ * type system itself.
+ */
 void
 g_type_plugin_complete_type_info (GTypePlugin     *plugin,
                                  GType            g_type,
@@ -82,6 +171,18 @@ g_type_plugin_complete_type_info (GTypePlugin     *plugin,
                             value_table);
 }
 
+/**
+ * g_type_plugin_complete_interface_info:
+ * @plugin: the #GTypePlugin
+ * @instance_type: the #GType of an instantiable type to which the interface
+ *  is added
+ * @interface_type: the #GType of the interface whose info is completed
+ * @info: the #GInterfaceInfo to fill in
+ * 
+ * Calls the @complete_interface_info function from the #GTypePluginClass 
+ * of @plugin. There should be no need to use this function outside of the 
+ * GObject type system itself.
+ */
 void
 g_type_plugin_complete_interface_info (GTypePlugin    *plugin,
                                       GType           instance_type,