improve bloom filter on send
[platform/upstream/glib.git] / gio / gactiongroup.c
index 4a585df..c608a4a 100644 (file)
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General
- * Public License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
- * Boston, MA 02111-1307, USA.
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  *
  * Authors: Ryan Lortie <desrt@desrt.ca>
  */
 
+#include "config.h"
 #include "gactiongroup.h"
-#include "gio-marshal.h"
+#include "gaction.h"
+#include "glibintl.h"
 
 /**
  * SECTION:gactiongroup
  * @title: GActionGroup
- * @short_description: a group of actions
- *
- * #GActionGroup represents a group of actions.
+ * @short_description: A group of actions
+ * @include: gio/gio.h
+ * @see_also: #GAction
+ *
+ * #GActionGroup represents a group of actions. Actions can be used to
+ * expose functionality in a structured way, either from one part of a
+ * program to another, or to the outside world. Action groups are often
+ * used together with a #GMenuModel that provides additional
+ * representation data for displaying the actions to the user, e.g. in
+ * a menu.
+ *
+ * The main way to interact with the actions in a GActionGroup is to
+ * activate them with g_action_group_activate_action(). Activating an
+ * action may require a #GVariant parameter. The required type of the
+ * parameter can be inquired with g_action_group_get_action_parameter_type().
+ * Actions may be disabled, see g_action_group_get_action_enabled().
+ * Activating a disabled action has no effect.
+ *
+ * Actions may optionally have a state in the form of a #GVariant. The
+ * current state of an action can be inquired with
+ * g_action_group_get_action_state(). Activating a stateful action may
+ * change its state, but it is also possible to set the state by calling
+ * g_action_group_change_action_state().
+ *
+ * As typical example, consider a text editing application which has an
+ * option to change the current font to 'bold'. A good way to represent
+ * this would be a stateful action, with a boolean state. Activating the
+ * action would toggle the state.
  *
  * Each action in the group has a unique name (which is a string).  All
  * method calls, except g_action_group_list_actions() take the name of
  * forces' (eg: UI, incoming D-Bus messages, etc.) are supposed to have
  * with actions.  'Internal' APIs (ie: ones meant only to be accessed by
  * the action group implementation) are found on subclasses.  This is
- * why you will find -- for example -- g_action_group_get_enabled() but
- * not an equivalent <function>set()</function> call.
+ * why you will find - for example - g_action_group_get_action_enabled()
+ * but not an equivalent set() call.
  *
  * Signals are emitted on the action group in response to state changes
  * on individual actions.
+ *
+ * Implementations of #GActionGroup should provide implementations for
+ * the virtual functions g_action_group_list_actions() and
+ * g_action_group_query_action().  The other virtual functions should
+ * not be implemented - their "wrappers" are actually implemented with
+ * calls to g_action_group_query_action().
+ */
+
+/**
+ * GActionGroupInterface:
+ * @has_action: the virtual function pointer for g_action_group_has_action()
+ * @list_actions: the virtual function pointer for g_action_group_list_actions()
+ * @get_action_parameter_type: the virtual function pointer for g_action_group_get_action_parameter_type()
+ * @get_action_state_type: the virtual function pointer for g_action_group_get_action_state_type()
+ * @get_action_state_hint: the virtual function pointer for g_action_group_get_action_state_hint()
+ * @get_action_enabled: the virtual function pointer for g_action_group_get_action_enabled()
+ * @get_action_state: the virtual function pointer for g_action_group_get_action_state()
+ * @change_action_state: the virtual function pointer for g_action_group_change_action_state()
+ * @query_action: the virtual function pointer for g_action_group_query_action()
+ * @activate_action: the virtual function pointer for g_action_group_activate_action()
+ * @change_action_state: the virtual function pointer for g_action_group_change_action_state()
+ * @action_added: the class closure for the #GActionGroup::action-added signal
+ * @action_removed: the class closure for the #GActionGroup::action-removed signal
+ * @action_enabled_changed: the class closure for the #GActionGroup::action-enabled-changed signal
+ * @action_state_changed: the class closure for the #GActionGroup::action-enabled-changed signal
+ *
+ * The virtual function table for #GActionGroup.
+ *
+ * Since: 2.28
  **/
 
-G_DEFINE_ABSTRACT_TYPE (GActionGroup, g_action_group, G_TYPE_OBJECT)
+G_DEFINE_INTERFACE (GActionGroup, g_action_group, G_TYPE_OBJECT)
 
 enum
 {
@@ -58,28 +112,150 @@ enum
 
 static guint g_action_group_signals[NR_SIGNALS];
 
-static void
-g_action_group_init (GActionGroup *action_group)
+static gboolean
+g_action_group_real_has_action (GActionGroup *action_group,
+                                const gchar  *action_name)
+{
+  return g_action_group_query_action (action_group, action_name, NULL, NULL, NULL, NULL, NULL);
+}
+
+static gboolean
+g_action_group_real_get_action_enabled (GActionGroup *action_group,
+                                        const gchar  *action_name)
+{
+  gboolean enabled = FALSE;
+
+  g_action_group_query_action (action_group, action_name, &enabled, NULL, NULL, NULL, NULL);
+
+  return enabled;
+}
+
+static const GVariantType *
+g_action_group_real_get_action_parameter_type (GActionGroup *action_group,
+                                               const gchar  *action_name)
 {
+  const GVariantType *type = NULL;
+
+  g_action_group_query_action (action_group, action_name, NULL, &type, NULL, NULL, NULL);
+
+  return type;
+}
+
+static const GVariantType *
+g_action_group_real_get_action_state_type (GActionGroup *action_group,
+                                           const gchar  *action_name)
+{
+  const GVariantType *type = NULL;
+
+  g_action_group_query_action (action_group, action_name, NULL, NULL, &type, NULL, NULL);
+
+  return type;
+}
+
+static GVariant *
+g_action_group_real_get_action_state_hint (GActionGroup *action_group,
+                                           const gchar  *action_name)
+{
+  GVariant *hint = NULL;
+
+  g_action_group_query_action (action_group, action_name, NULL, NULL, NULL, &hint, NULL);
+
+  return hint;
+}
+
+static GVariant *
+g_action_group_real_get_action_state (GActionGroup *action_group,
+                                      const gchar  *action_name)
+{
+  GVariant *state = NULL;
+
+  g_action_group_query_action (action_group, action_name, NULL, NULL, NULL, NULL, &state);
+
+  return state;
+}
+
+static gboolean
+g_action_group_real_query_action (GActionGroup        *action_group,
+                                  const gchar         *action_name,
+                                  gboolean            *enabled,
+                                  const GVariantType **parameter_type,
+                                  const GVariantType **state_type,
+                                  GVariant           **state_hint,
+                                  GVariant           **state)
+{
+  GActionGroupInterface *iface = G_ACTION_GROUP_GET_IFACE (action_group);
+
+  /* we expect implementations to override this method, but we also
+   * allow for implementations that existed before this method was
+   * introduced to override the individual accessors instead.
+   *
+   * detect the case that neither has happened and report it.
+   */
+  if G_UNLIKELY (iface->has_action == g_action_group_real_has_action ||
+                 iface->get_action_enabled == g_action_group_real_get_action_enabled ||
+                 iface->get_action_parameter_type == g_action_group_real_get_action_parameter_type ||
+                 iface->get_action_state_type == g_action_group_real_get_action_state_type ||
+                 iface->get_action_state_hint == g_action_group_real_get_action_state_hint ||
+                 iface->get_action_state == g_action_group_real_get_action_state)
+    {
+      g_critical ("Class '%s' implements GActionGroup interface without overriding "
+                  "query_action() method -- bailing out to avoid infinite recursion.",
+                  G_OBJECT_TYPE_NAME (action_group));
+      return FALSE;
+    }
+
+  if (!(* iface->has_action) (action_group, action_name))
+    return FALSE;
+
+  if (enabled != NULL)
+    *enabled = (* iface->get_action_enabled) (action_group, action_name);
+
+  if (parameter_type != NULL)
+    *parameter_type = (* iface->get_action_parameter_type) (action_group, action_name);
+
+  if (state_type != NULL)
+    *state_type = (* iface->get_action_state_type) (action_group, action_name);
+
+  if (state_hint != NULL)
+    *state_hint = (* iface->get_action_state_hint) (action_group, action_name);
+
+  if (state != NULL)
+    *state = (* iface->get_action_state) (action_group, action_name);
+
+  return TRUE;
 }
 
 static void
-g_action_group_class_init (GActionGroupClass *class)
+g_action_group_default_init (GActionGroupInterface *iface)
 {
+  iface->has_action = g_action_group_real_has_action;
+  iface->get_action_enabled = g_action_group_real_get_action_enabled;
+  iface->get_action_parameter_type = g_action_group_real_get_action_parameter_type;
+  iface->get_action_state_type = g_action_group_real_get_action_state_type;
+  iface->get_action_state_hint = g_action_group_real_get_action_state_hint;
+  iface->get_action_state = g_action_group_real_get_action_state;
+  iface->query_action = g_action_group_real_query_action;
+
   /**
    * GActionGroup::action-added:
    * @action_group: the #GActionGroup that changed
    * @action_name: the name of the action in @action_group
    *
-   * Signals that a new action was just added to the group.  This signal
-   * is emitted after the action has been added and is now visible.
+   * Signals that a new action was just added to the group.
+   * This signal is emitted after the action has been added
+   * and is now visible.
+   *
+   * Since: 2.28
    **/
   g_action_group_signals[SIGNAL_ACTION_ADDED] =
-    g_signal_new ("action-added",
-                  G_TYPE_ACTION_GROUP, G_SIGNAL_RUN_LAST,
-                  G_STRUCT_OFFSET (GActionGroupClass, action_added),
-                  NULL, NULL, g_cclosure_marshal_VOID__STRING,
-                  G_TYPE_NONE, 1, G_TYPE_STRING);
+    g_signal_new (I_("action-added"),
+                  G_TYPE_ACTION_GROUP,
+                  G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
+                  G_STRUCT_OFFSET (GActionGroupInterface, action_added),
+                  NULL, NULL,
+                  g_cclosure_marshal_VOID__STRING,
+                  G_TYPE_NONE, 1,
+                  G_TYPE_STRING);
 
   /**
    * GActionGroup::action-removed:
@@ -89,13 +265,18 @@ g_action_group_class_init (GActionGroupClass *class)
    * Signals that an action is just about to be removed from the group.
    * This signal is emitted before the action is removed, so the action
    * is still visible and can be queried from the signal handler.
+   *
+   * Since: 2.28
    **/
   g_action_group_signals[SIGNAL_ACTION_REMOVED] =
-    g_signal_new ("action-removed",
-                  G_TYPE_ACTION_GROUP, G_SIGNAL_RUN_LAST,
-                  G_STRUCT_OFFSET (GActionGroupClass, action_removed),
-                  NULL, NULL, g_cclosure_marshal_VOID__STRING,
-                  G_TYPE_NONE, 1, G_TYPE_STRING);
+    g_signal_new (I_("action-removed"),
+                  G_TYPE_ACTION_GROUP,
+                  G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
+                  G_STRUCT_OFFSET (GActionGroupInterface, action_removed),
+                  NULL, NULL,
+                  g_cclosure_marshal_VOID__STRING,
+                  G_TYPE_NONE, 1,
+                  G_TYPE_STRING);
 
 
   /**
@@ -105,13 +286,20 @@ g_action_group_class_init (GActionGroupClass *class)
    * @enabled: whether the action is enabled or not
    *
    * Signals that the enabled status of the named action has changed.
+   *
+   * Since: 2.28
    **/
   g_action_group_signals[SIGNAL_ACTION_ENABLED_CHANGED] =
-    g_signal_new ("action-enabled-changed",
-                  G_TYPE_ACTION_GROUP, G_SIGNAL_RUN_LAST,
-                  G_STRUCT_OFFSET (GActionGroupClass, action_enabled_changed),
-                  NULL, NULL, _gio_marshal_VOID__STRING_BOOLEAN,
-                  G_TYPE_NONE, 2, G_TYPE_STRING, G_TYPE_BOOLEAN);
+    g_signal_new (I_("action-enabled-changed"),
+                  G_TYPE_ACTION_GROUP,
+                  G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
+                  G_STRUCT_OFFSET (GActionGroupInterface,
+                                   action_enabled_changed),
+                  NULL, NULL,
+                  NULL,
+                  G_TYPE_NONE, 2,
+                  G_TYPE_STRING,
+                  G_TYPE_BOOLEAN);
 
   /**
    * GActionGroup::action-state-changed:
@@ -120,18 +308,26 @@ g_action_group_class_init (GActionGroupClass *class)
    * @value: the new value of the state
    *
    * Signals that the state of the named action has changed.
+   *
+   * Since: 2.28
    **/
   g_action_group_signals[SIGNAL_ACTION_STATE_CHANGED] =
-    g_signal_new ("action-state-changed",
-                  G_TYPE_ACTION_GROUP, G_SIGNAL_RUN_LAST,
-                  G_STRUCT_OFFSET (GActionGroupClass, action_state_changed),
-                  NULL, NULL, _gio_marshal_VOID__STRING_VARIANT,
-                  G_TYPE_NONE, 2, G_TYPE_STRING, G_TYPE_VARIANT);
-
+    g_signal_new (I_("action-state-changed"),
+                  G_TYPE_ACTION_GROUP,
+                  G_SIGNAL_RUN_LAST |
+                  G_SIGNAL_DETAILED |
+                  G_SIGNAL_MUST_COLLECT,
+                  G_STRUCT_OFFSET (GActionGroupInterface,
+                                   action_state_changed),
+                  NULL, NULL,
+                  NULL,
+                  G_TYPE_NONE, 2,
+                  G_TYPE_STRING,
+                  G_TYPE_VARIANT);
 }
 
 /**
- * g_action_group_has_action:
+ * g_action_group_list_actions:
  * @action_group: a #GActionGroup
  *
  * Lists the actions contained within @action_group.
@@ -139,14 +335,17 @@ g_action_group_class_init (GActionGroupClass *class)
  * The caller is responsible for freeing the list with g_strfreev() when
  * it is no longer required.
  *
- * Returns: a list of the actions in the group
+ * Returns: (transfer full): a %NULL-terminated array of the names of the
+ * actions in the groupb
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 gchar **
 g_action_group_list_actions (GActionGroup *action_group)
 {
-  return G_ACTION_GROUP_GET_CLASS (action_group)
+  g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
+
+  return G_ACTION_GROUP_GET_IFACE (action_group)
     ->list_actions (action_group);
 }
 
@@ -159,27 +358,29 @@ g_action_group_list_actions (GActionGroup *action_group)
  *
  * Returns: whether the named action exists
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 gboolean
 g_action_group_has_action (GActionGroup *action_group,
                            const gchar  *action_name)
 {
-  return G_ACTION_GROUP_GET_CLASS (action_group)
+  g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), FALSE);
+
+  return G_ACTION_GROUP_GET_IFACE (action_group)
     ->has_action (action_group, action_name);
 }
 
 /**
- * g_action_group_get_parameter_type:
+ * g_action_group_get_action_parameter_type:
  * @action_group: a #GActionGroup
  * @action_name: the name of the action to query
  *
  * Queries the type of the parameter that must be given when activating
  * the named action within @action_group.
  *
- * When activating the action using g_action_group_activate(), the
- * #GVariant given to that function must be of the type returned by this
- * function.
+ * When activating the action using g_action_group_activate_action(),
+ * the #GVariant given to that function must be of the type returned
+ * by this function.
  *
  * In the case that this function returns %NULL, you must not give any
  * #GVariant, but %NULL instead.
@@ -188,20 +389,22 @@ g_action_group_has_action (GActionGroup *action_group,
  * possible for an action to be removed and for a new action to be added
  * with the same name but a different parameter type.
  *
- * Returns: (allow-none): the parameter type
+ * Returns: (nullable): the parameter type
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 const GVariantType *
-g_action_group_get_parameter_type (GActionGroup *action_group,
-                                   const gchar  *action_name)
+g_action_group_get_action_parameter_type (GActionGroup *action_group,
+                                          const gchar  *action_name)
 {
-  return G_ACTION_GROUP_GET_CLASS (action_group)
-    ->get_parameter_type (action_group, action_name);
+  g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
+
+  return G_ACTION_GROUP_GET_IFACE (action_group)
+    ->get_action_parameter_type (action_group, action_name);
 }
 
 /**
- * g_action_group_get_state_type:
+ * g_action_group_get_action_state_type:
  * @action_group: a #GActionGroup
  * @action_name: the name of the action to query
  *
@@ -209,32 +412,36 @@ g_action_group_get_parameter_type (GActionGroup *action_group,
  * @action_group.
  *
  * If the action is stateful then this function returns the
- * #GVariantType of the state.  All calls to g_action_group_set_state()
- * must give a #GVariant of this type and g_action_group_get_state()
- * will return a #GVariant of the same type.
+ * #GVariantType of the state.  All calls to
+ * g_action_group_change_action_state() must give a #GVariant of this
+ * type and g_action_group_get_action_state() will return a #GVariant
+ * of the same type.
  *
  * If the action is not stateful then this function will return %NULL.
- * In that case, g_action_group_get_state() will return %NULL and you
- * must not call g_action_group_set_state().
+ * In that case, g_action_group_get_action_state() will return %NULL
+ * and you must not call g_action_group_change_action_state().
  *
  * The state type of a particular action will never change but it is
  * possible for an action to be removed and for a new action to be added
  * with the same name but a different state type.
  *
- * Returns: (allow-none): the state type, if the action is stateful
+ * Returns: (nullable) (transfer full): the state type, if the action
+ * is stateful
  *
- * Since: 2.26
+ * Since: 2.28
  **/
- const GVariantType *
-g_action_group_get_state_type (GActionGroup *action_group,
-                               const gchar  *action_name)
+const GVariantType *
+g_action_group_get_action_state_type (GActionGroup *action_group,
+                                      const gchar  *action_name)
 {
-  return G_ACTION_GROUP_GET_CLASS (action_group)
-    ->get_state_type (action_group, action_name);
+  g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
+
+  return G_ACTION_GROUP_GET_IFACE (action_group)
+    ->get_action_state_type (action_group, action_name);
 }
 
 /**
- * g_action_group_get_state_hint:
+ * g_action_group_get_action_state_hint:
  * @action_group: a #GActionGroup
  * @action_name: the name of the action to query
  *
@@ -257,20 +464,22 @@ g_action_group_get_state_type (GActionGroup *action_group,
  * The return value (if non-%NULL) should be freed with
  * g_variant_unref() when it is no longer required.
  *
- * Returns: (allow-none): the state range hint
+ * Returns: (nullable) (transfer full): the state range hint
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 GVariant *
-g_action_group_get_state_hint (GActionGroup *action_group,
-                                const gchar  *action_name)
+g_action_group_get_action_state_hint (GActionGroup *action_group,
+                                      const gchar  *action_name)
 {
-  return G_ACTION_GROUP_GET_CLASS (action_group)
-    ->get_state_hint (action_group, action_name);
+  g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
+
+  return G_ACTION_GROUP_GET_IFACE (action_group)
+    ->get_action_state_hint (action_group, action_name);
 }
 
 /**
- * g_action_group_get_enabled:
+ * g_action_group_get_action_enabled:
  * @action_group: a #GActionGroup
  * @action_name: the name of the action to query
  *
@@ -281,18 +490,20 @@ g_action_group_get_state_hint (GActionGroup *action_group,
  *
  * Returns: whether or not the action is currently enabled
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 gboolean
-g_action_group_get_enabled (GActionGroup *action_group,
-                            const gchar  *action_name)
+g_action_group_get_action_enabled (GActionGroup *action_group,
+                                   const gchar  *action_name)
 {
-  return G_ACTION_GROUP_GET_CLASS (action_group)
-    ->get_enabled (action_group, action_name);
+  g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), FALSE);
+
+  return G_ACTION_GROUP_GET_IFACE (action_group)
+    ->get_action_enabled (action_group, action_name);
 }
 
 /**
- * g_action_group_get_state:
+ * g_action_group_get_action_state:
  * @action_group: a #GActionGroup
  * @action_name: the name of the action to query
  *
@@ -300,25 +511,27 @@ g_action_group_get_enabled (GActionGroup *action_group,
  *
  * If the action is not stateful then %NULL will be returned.  If the
  * action is stateful then the type of the return value is the type
- * given by g_action_group_get_state_type().
+ * given by g_action_group_get_action_state_type().
  *
  * The return value (if non-%NULL) should be freed with
  * g_variant_unref() when it is no longer required.
  *
- * Returns: (allow-none): the current state of the action
+ * Returns: (nullable): the current state of the action
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 GVariant *
-g_action_group_get_state (GActionGroup *action_group,
-                          const gchar  *action_name)
+g_action_group_get_action_state (GActionGroup *action_group,
+                                 const gchar  *action_name)
 {
-  return G_ACTION_GROUP_GET_CLASS (action_group)
-    ->get_state (action_group, action_name);
+  g_return_val_if_fail (G_IS_ACTION_GROUP (action_group), NULL);
+
+  return G_ACTION_GROUP_GET_IFACE (action_group)
+    ->get_action_state (action_group, action_name);
 }
 
 /**
- * g_action_group_set_state:
+ * g_action_group_change_action_state:
  * @action_group: a #GActionGroup
  * @action_name: the name of the action to request the change on
  * @value: the new state
@@ -327,25 +540,31 @@ g_action_group_get_state (GActionGroup *action_group,
  * changed to @value.
  *
  * The action must be stateful and @value must be of the correct type.
- * See g_action_group_get_state_type().
+ * See g_action_group_get_action_state_type().
  *
  * This call merely requests a change.  The action may refuse to change
  * its state or may change its state to something other than @value.
- * See g_action_group_get_state_hint().
+ * See g_action_group_get_action_state_hint().
  *
- * Since: 2.26
+ * If the @value GVariant is floating, it is consumed.
+ *
+ * Since: 2.28
  **/
 void
-g_action_group_set_state (GActionGroup *action_group,
-                          const gchar  *action_name,
-                          GVariant     *value)
+g_action_group_change_action_state (GActionGroup *action_group,
+                                    const gchar  *action_name,
+                                    GVariant     *value)
 {
-  G_ACTION_GROUP_GET_CLASS (action_group)
-    ->set_state (action_group, action_name, value);
+  g_return_if_fail (G_IS_ACTION_GROUP (action_group));
+  g_return_if_fail (action_name != NULL);
+  g_return_if_fail (value != NULL);
+
+  G_ACTION_GROUP_GET_IFACE (action_group)
+    ->change_action_state (action_group, action_name, value);
 }
 
 /**
- * g_action_group_activate:
+ * g_action_group_activate_action:
  * @action_group: a #GActionGroup
  * @action_name: the name of the action to activate
  * @parameter: (allow-none): parameters to the activation
@@ -355,17 +574,20 @@ g_action_group_set_state (GActionGroup *action_group,
  * If the action is expecting a parameter, then the correct type of
  * parameter must be given as @parameter.  If the action is expecting no
  * parameters then @parameter must be %NULL.  See
- * g_action_group_get_parameter_type().
+ * g_action_group_get_action_parameter_type().
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 void
-g_action_group_activate (GActionGroup *action_group,
-                         const gchar  *action_name,
-                         GVariant     *parameter)
+g_action_group_activate_action (GActionGroup *action_group,
+                                const gchar  *action_name,
+                                GVariant     *parameter)
 {
-  G_ACTION_GROUP_GET_CLASS (action_group)
-    ->activate (action_group, action_name, parameter);
+  g_return_if_fail (G_IS_ACTION_GROUP (action_group));
+  g_return_if_fail (action_name != NULL);
+
+  G_ACTION_GROUP_GET_IFACE (action_group)
+    ->activate_action (action_group, action_name, parameter);
 }
 
 /**
@@ -373,19 +595,23 @@ g_action_group_activate (GActionGroup *action_group,
  * @action_group: a #GActionGroup
  * @action_name: the name of an action in the group
  *
- * Emits the "action-added" signal on @action_group.
+ * Emits the #GActionGroup::action-added signal on @action_group.
  *
  * This function should only be called by #GActionGroup implementations.
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 void
 g_action_group_action_added (GActionGroup *action_group,
                              const gchar  *action_name)
 {
+  g_return_if_fail (G_IS_ACTION_GROUP (action_group));
+  g_return_if_fail (action_name != NULL);
+
   g_signal_emit (action_group,
                  g_action_group_signals[SIGNAL_ACTION_ADDED],
-                 g_quark_try_string (action_name), action_name);
+                 g_quark_try_string (action_name),
+                 action_name);
 }
 
 /**
@@ -393,19 +619,23 @@ g_action_group_action_added (GActionGroup *action_group,
  * @action_group: a #GActionGroup
  * @action_name: the name of an action in the group
  *
- * Emits the "action-removed" signal on @action_group.
+ * Emits the #GActionGroup::action-removed signal on @action_group.
  *
  * This function should only be called by #GActionGroup implementations.
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 void
 g_action_group_action_removed (GActionGroup *action_group,
                                const gchar  *action_name)
 {
+  g_return_if_fail (G_IS_ACTION_GROUP (action_group));
+  g_return_if_fail (action_name != NULL);
+
   g_signal_emit (action_group,
                  g_action_group_signals[SIGNAL_ACTION_REMOVED],
-                 g_quark_try_string (action_name), action_name);
+                 g_quark_try_string (action_name),
+                 action_name);
 }
 
 /**
@@ -414,20 +644,27 @@ g_action_group_action_removed (GActionGroup *action_group,
  * @action_name: the name of an action in the group
  * @enabled: whether or not the action is now enabled
  *
- * Emits the "action-enabled-changed" signal on @action_group.
+ * Emits the #GActionGroup::action-enabled-changed signal on @action_group.
  *
  * This function should only be called by #GActionGroup implementations.
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 void
 g_action_group_action_enabled_changed (GActionGroup *action_group,
                                        const gchar  *action_name,
                                        gboolean      enabled)
 {
+  g_return_if_fail (G_IS_ACTION_GROUP (action_group));
+  g_return_if_fail (action_name != NULL);
+
+  enabled = !!enabled;
+
   g_signal_emit (action_group,
                  g_action_group_signals[SIGNAL_ACTION_ENABLED_CHANGED],
-                 g_quark_try_string (action_name), action_name);
+                 g_quark_try_string (action_name),
+                 action_name,
+                 enabled);
 }
 
 /**
@@ -436,18 +673,78 @@ g_action_group_action_enabled_changed (GActionGroup *action_group,
  * @action_name: the name of an action in the group
  * @state: the new state of the named action
  *
- * Emits the "action-state-changed" signal on @action_group.
+ * Emits the #GActionGroup::action-state-changed signal on @action_group.
  *
  * This function should only be called by #GActionGroup implementations.
  *
- * Since: 2.26
+ * Since: 2.28
  **/
 void
 g_action_group_action_state_changed (GActionGroup *action_group,
                                      const gchar  *action_name,
                                      GVariant     *state)
 {
+  g_return_if_fail (G_IS_ACTION_GROUP (action_group));
+  g_return_if_fail (action_name != NULL);
+
   g_signal_emit (action_group,
                  g_action_group_signals[SIGNAL_ACTION_STATE_CHANGED],
-                 g_quark_try_string (action_name), action_name);
+                 g_quark_try_string (action_name),
+                 action_name,
+                 state);
+}
+
+/**
+ * g_action_group_query_action:
+ * @action_group: a #GActionGroup
+ * @action_name: the name of an action in the group
+ * @enabled: (out): if the action is presently enabled
+ * @parameter_type: (out) (allow-none): the parameter type, or %NULL if none needed
+ * @state_type: (out) (allow-none): the state type, or %NULL if stateless
+ * @state_hint: (out) (allow-none): the state hint, or %NULL if none
+ * @state: (out) (allow-none): the current state, or %NULL if stateless
+ *
+ * Queries all aspects of the named action within an @action_group.
+ *
+ * This function acquires the information available from
+ * g_action_group_has_action(), g_action_group_get_action_enabled(),
+ * g_action_group_get_action_parameter_type(),
+ * g_action_group_get_action_state_type(),
+ * g_action_group_get_action_state_hint() and
+ * g_action_group_get_action_state() with a single function call.
+ *
+ * This provides two main benefits.
+ *
+ * The first is the improvement in efficiency that comes with not having
+ * to perform repeated lookups of the action in order to discover
+ * different things about it.  The second is that implementing
+ * #GActionGroup can now be done by only overriding this one virtual
+ * function.
+ *
+ * The interface provides a default implementation of this function that
+ * calls the individual functions, as required, to fetch the
+ * information.  The interface also provides default implementations of
+ * those functions that call this function.  All implementations,
+ * therefore, must override either this function or all of the others.
+ *
+ * If the action exists, %TRUE is returned and any of the requested
+ * fields (as indicated by having a non-%NULL reference passed in) are
+ * filled.  If the action doesn't exist, %FALSE is returned and the
+ * fields may or may not have been modified.
+ *
+ * Returns: %TRUE if the action exists, else %FALSE
+ *
+ * Since: 2.32
+ **/
+gboolean
+g_action_group_query_action (GActionGroup        *action_group,
+                             const gchar         *action_name,
+                             gboolean            *enabled,
+                             const GVariantType **parameter_type,
+                             const GVariantType **state_type,
+                             GVariant           **state_hint,
+                             GVariant           **state)
+{
+  return G_ACTION_GROUP_GET_IFACE (action_group)
+    ->query_action (action_group, action_name, enabled, parameter_type, state_type, state_hint, state);
 }