1 files changed, 189 insertions, 0 deletions
diff --git a/src/gtkactionobserver.c b/src/gtkactionobserver.c
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+/*
+ * Copyright © 2011 Canonical Limited
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * licence or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#include "config.h"
+
+#include "gtkactionobserver.h"
+
+G_DEFINE_INTERFACE (GtkActionObserver, gtk_action_observer, G_TYPE_OBJECT)
+
+/**
+ * SECTION:gtkactionobserver
+ * @short_description: an interface implemented by objects that are
+ *                     interested in monitoring actions for changes
+ *
+ * GtkActionObserver is a simple interface allowing objects that wish to
+ * be notified of changes to actions to be notified of those changes.
+ *
+ * It is also possible to monitor changes to action groups using
+ * #GObject signals, but there are a number of reasons that this
+ * approach could become problematic:
+ *
+ *  - there are four separate signals that must be manually connected
+ *    and disconnected
+ *
+ *  - when a large number of different observers wish to monitor a
+ *    (usually disjoint) set of actions within the same action group,
+ *    there is only one way to avoid having all notifications delivered
+ *    to all observers: signal detail.  In order to use signal detail,
+ *    each action name must be quarked, which is not always practical.
+ *
+ *  - even if quarking is acceptable, #GObject signal details are
+ *    implemented by scanning a linked list, so there is no real
+ *    decrease in complexity
+ */
+
+void
+gtk_action_observer_default_init (GtkActionObserverInterface *class)
+{
+}
+
+/**
+ * gtk_action_observer_action_added:
+ * @observer: a #GtkActionObserver
+ * @observable: the source of the event
+ * @action_name: the name of the action
+ * @enabled: %TRUE if the action is now enabled
+ * @parameter_type: the parameter type for action invocations, or %NULL
+ *                  if no parameter is required
+ * @state: the current state of the action, or %NULL if the action is
+ *         stateless
+ *
+ * This function is called when an action that the observer is
+ * registered to receive events for is added.
+ *
+ * This function should only be called by objects with which the
+ * observer has explicitly registered itself to receive events.
+ */
+void
+gtk_action_observer_action_added (GtkActionObserver   *observer,
+                                  GtkActionObservable *observable,
+                                  const gchar         *action_name,
+                                  const GVariantType  *parameter_type,
+                                  gboolean             enabled,
+                                  GVariant            *state)
+{
+  g_return_if_fail (GTK_IS_ACTION_OBSERVER (observer));
+
+  GTK_ACTION_OBSERVER_GET_IFACE (observer)
+    ->action_added (observer, observable, action_name, parameter_type, enabled, state);
+}
+
+/**
+ * gtk_action_observer_action_enabled_changed:
+ * @observer: a #GtkActionObserver
+ * @observable: the source of the event
+ * @action_name: the name of the action
+ * @enabled: %TRUE if the action is now enabled
+ *
+ * This function is called when an action that the observer is
+ * registered to receive events for becomes enabled or disabled.
+ *
+ * This function should only be called by objects with which the
+ * observer has explicitly registered itself to receive events.
+ */
+void
+gtk_action_observer_action_enabled_changed (GtkActionObserver   *observer,
+                                            GtkActionObservable *observable,
+                                            const gchar         *action_name,
+                                            gboolean             enabled)
+{
+  g_return_if_fail (GTK_IS_ACTION_OBSERVER (observer));
+
+  GTK_ACTION_OBSERVER_GET_IFACE (observer)
+    ->action_enabled_changed (observer, observable, action_name, enabled);
+}
+
+/**
+ * gtk_action_observer_action_state_changed:
+ * @observer: a #GtkActionObserver
+ * @observable: the source of the event
+ * @action_name: the name of the action
+ * @state: the new state of the action
+ *
+ * This function is called when an action that the observer is
+ * registered to receive events for changes to its state.
+ *
+ * This function should only be called by objects with which the
+ * observer has explicitly registered itself to receive events.
+ */
+void
+gtk_action_observer_action_state_changed (GtkActionObserver   *observer,
+                                          GtkActionObservable *observable,
+                                          const gchar         *action_name,
+                                          GVariant            *state)
+{
+  g_return_if_fail (GTK_IS_ACTION_OBSERVER (observer));
+
+  GTK_ACTION_OBSERVER_GET_IFACE (observer)
+    ->action_state_changed (observer, observable, action_name, state);
+}
+
+/**
+ * gtk_action_observer_action_removed:
+ * @observer: a #GtkActionObserver
+ * @observable: the source of the event
+ * @action_name: the name of the action
+ *
+ * This function is called when an action that the observer is
+ * registered to receive events for is removed.
+ *
+ * This function should only be called by objects with which the
+ * observer has explicitly registered itself to receive events.
+ */
+void
+gtk_action_observer_action_removed (GtkActionObserver   *observer,
+                                    GtkActionObservable *observable,
+                                    const gchar         *action_name)
+{
+  g_return_if_fail (GTK_IS_ACTION_OBSERVER (observer));
+
+  GTK_ACTION_OBSERVER_GET_IFACE (observer)
+    ->action_removed (observer, observable, action_name);
+}
+
+/**
+ * gtk_action_observer_primary_accel_changed:
+ * @observer: a #GtkActionObserver
+ * @observable: the source of the event
+ * @action_name: the name of the action
+ * @action_and_target: detailed action of the changed accel, in "action and target" format
+ *
+ * This function is called when an action that the observer is
+ * registered to receive events for has one of its accelerators changed.
+ *
+ * Accelerator changes are reported for all targets associated with the
+ * action.  The @action_and_target string should be used to check if the
+ * reported target is the one that the observer is interested in.
+ */
+void
+gtk_action_observer_primary_accel_changed (GtkActionObserver   *observer,
+                                           GtkActionObservable *observable,
+                                           const gchar         *action_name,
+                                           const gchar         *action_and_target)
+{
+  GtkActionObserverInterface *iface;
+
+  g_return_if_fail (GTK_IS_ACTION_OBSERVER (observer));
+
+  iface = GTK_ACTION_OBSERVER_GET_IFACE (observer);
+
+  if (iface->primary_accel_changed)
+    iface->primary_accel_changed (observer, observable, action_name, action_and_target);
+}