Introduce UnityMenuModel and UnityQmlMenuModel

UnityMenuModel serves the same purpose as QMenuModel, but it is based on
GtkMenuTracker and has a different API.

GtkMenuTracker is maintained in gtk, but meant to be copy-and-pasted into other
consumers of menu models. It does not introduce new dependencies. It does give
us access to all the features that GMenuModel has.

17 files changed, 3089 insertions, 2 deletions

diff --git a/libqmenumodel/QMenuModel/plugin.cpp b/libqmenumodel/QMenuModel/plugin.cpp
index ee05fff..0205102 100644
--- a/libqmenumodel/QMenuModel/plugin.cpp
+++ b/libqmenumodel/QMenuModel/plugin.cpp
@@ -22,6 +22,7 @@
 #include "qdbusmenumodel.h"
 #include "qdbusactiongroup.h"
 #include "qstateaction.h"
+#include "unityqmlmenumodel.h"
 
 #include <QtQml>
 
@@ -36,6 +37,5 @@ void QMenuModelQmlPlugin::registerTypes(const char *uri)
 
     qmlRegisterType<QDBusMenuModel>(uri, 0, 1, "QDBusMenuModel");
     qmlRegisterType<QDBusActionGroup>(uri, 0, 1, "QDBusActionGroup");
-
+    qmlRegisterType<UnityQmlMenuModel>(uri, 0, 1, "UnityMenuModel");
 }
-
diff --git a/libqmenumodel/src/CMakeLists.txt b/libqmenumodel/src/CMakeLists.txt
index 1fb89df..cd81371 100644
--- a/libqmenumodel/src/CMakeLists.txt
+++ b/libqmenumodel/src/CMakeLists.txt
@@ -9,6 +9,19 @@ set(QMENUMODEL_SRC
     qdbusmenumodel.cpp
     qdbusactiongroup.cpp
     qstateaction.cpp
+    unitymenumodel.cpp
+    unitymenumodel.h
+    unityqmlmenumodel.cpp
+    gtk/gtkactionmuxer.c
+    gtk/gtkactionmuxer.h
+    gtk/gtkactionobservable.c
+    gtk/gtkactionobservable.h
+    gtk/gtkactionobserver.c
+    gtk/gtkactionobserver.h
+    gtk/gtkmenutracker.c
+    gtk/gtkmenutracker.h
+    gtk/gtkmenutrackeritem.c
+    gtk/gtkmenutrackeritem.h
 )
 
 set(SHAREDLIBNAME qmenumodel)
@@ -43,6 +56,7 @@ set(QMENUMODEL_HEADERS
     qdbusobject.h
     qmenumodel.h
     qstateaction.h
+    unitymenumodel.h
 )
 
 set(INCLUDEDIR qmenumodel)
diff --git a/libqmenumodel/src/gtk/config.h b/libqmenumodel/src/gtk/config.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/libqmenumodel/src/gtk/config.h
diff --git a/libqmenumodel/src/gtk/gtkactionmuxer.c b/libqmenumodel/src/gtk/gtkactionmuxer.c
new file mode 100644
index 0000000..4618564
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkactionmuxer.c
@@ -0,0 +1,778 @@
+/*
+ * 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/>.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#include "config.h"
+
+#include "gtkactionmuxer.h"
+
+#include "gtkactionobservable.h"
+#include "gtkactionobserver.h"
+
+#include <string.h>
+
+/**
+ * SECTION:gtkactionmuxer
+ * @short_description: Aggregate and monitor several action groups
+ *
+ * #GtkActionMuxer is a #GActionGroup and #GtkActionObservable that is
+ * capable of containing other #GActionGroup instances.
+ *
+ * The typical use is aggregating all of the actions applicable to a
+ * particular context into a single action group, with namespacing.
+ *
+ * Consider the case of two action groups -- one containing actions
+ * applicable to an entire application (such as 'quit') and one
+ * containing actions applicable to a particular window in the
+ * application (such as 'fullscreen').
+ *
+ * In this case, each of these action groups could be added to a
+ * #GtkActionMuxer with the prefixes "app" and "win", respectively.  This
+ * would expose the actions as "app.quit" and "win.fullscreen" on the
+ * #GActionGroup interface presented by the #GtkActionMuxer.
+ *
+ * Activations and state change requests on the #GtkActionMuxer are wired
+ * through to the underlying action group in the expected way.
+ *
+ * This class is typically only used at the site of "consumption" of
+ * actions (eg: when displaying a menu that contains many actions on
+ * different objects).
+ */
+
+static void     gtk_action_muxer_group_iface_init         (GActionGroupInterface        *iface);
+static void     gtk_action_muxer_observable_iface_init    (GtkActionObservableInterface *iface);
+
+typedef GObjectClass GtkActionMuxerClass;
+
+struct _GtkActionMuxer
+{
+  GObject parent_instance;
+
+  GHashTable *observed_actions;
+  GHashTable *groups;
+  GtkActionMuxer *parent;
+};
+
+G_DEFINE_TYPE_WITH_CODE (GtkActionMuxer, gtk_action_muxer, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_ACTION_GROUP, gtk_action_muxer_group_iface_init)
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_ACTION_OBSERVABLE, gtk_action_muxer_observable_iface_init))
+
+enum
+{
+  PROP_0,
+  PROP_PARENT,
+  NUM_PROPERTIES
+};
+
+static GParamSpec *properties[NUM_PROPERTIES];
+
+typedef struct
+{
+  GtkActionMuxer *muxer;
+  GSList       *watchers;
+  gchar        *fullname;
+} Action;
+
+typedef struct
+{
+  GtkActionMuxer *muxer;
+  GActionGroup *group;
+  gchar        *prefix;
+  gulong        handler_ids[4];
+} Group;
+
+static void
+gtk_action_muxer_append_group_actions (gpointer key,
+                                       gpointer value,
+                                       gpointer user_data)
+{
+  const gchar *prefix = key;
+  Group *group = value;
+  GArray *actions = user_data;
+  gchar **group_actions;
+  gchar **action;
+
+  group_actions = g_action_group_list_actions (group->group);
+  for (action = group_actions; *action; action++)
+    {
+      gchar *fullname;
+
+      fullname = g_strconcat (prefix, ".", *action, NULL);
+      g_array_append_val (actions, fullname);
+    }
+
+  g_strfreev (group_actions);
+}
+
+static gchar **
+gtk_action_muxer_list_actions (GActionGroup *action_group)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (action_group);
+  GArray *actions;
+
+  actions = g_array_new (TRUE, FALSE, sizeof (gchar *));
+
+  for ( ; muxer != NULL; muxer = muxer->parent)
+    {
+      g_hash_table_foreach (muxer->groups,
+                            gtk_action_muxer_append_group_actions,
+                            actions);
+    }
+
+  return (gchar **) g_array_free (actions, FALSE);
+}
+
+static Group *
+gtk_action_muxer_find_group (GtkActionMuxer  *muxer,
+                             const gchar     *full_name,
+                             const gchar    **action_name)
+{
+  const gchar *dot;
+  gchar *prefix;
+  Group *group;
+
+  dot = strchr (full_name, '.');
+
+  if (!dot)
+    return NULL;
+
+  prefix = g_strndup (full_name, dot - full_name);
+  group = g_hash_table_lookup (muxer->groups, prefix);
+  g_free (prefix);
+
+  if (action_name)
+    *action_name = dot + 1;
+
+  return group;
+}
+
+static void
+gtk_action_muxer_action_enabled_changed (GtkActionMuxer *muxer,
+                                         const gchar    *action_name,
+                                         gboolean        enabled)
+{
+  Action *action;
+  GSList *node;
+
+  action = g_hash_table_lookup (muxer->observed_actions, action_name);
+  for (node = action ? action->watchers : NULL; node; node = node->next)
+    gtk_action_observer_action_enabled_changed (node->data, GTK_ACTION_OBSERVABLE (muxer), action_name, enabled);
+  g_action_group_action_enabled_changed (G_ACTION_GROUP (muxer), action_name, enabled);
+}
+
+static void
+gtk_action_muxer_group_action_enabled_changed (GActionGroup *action_group,
+                                               const gchar  *action_name,
+                                               gboolean      enabled,
+                                               gpointer      user_data)
+{
+  Group *group = user_data;
+  gchar *fullname;
+
+  fullname = g_strconcat (group->prefix, ".", action_name, NULL);
+  gtk_action_muxer_action_enabled_changed (group->muxer, fullname, enabled);
+
+  g_free (fullname);
+}
+
+static void
+gtk_action_muxer_parent_action_enabled_changed (GActionGroup *action_group,
+                                                const gchar  *action_name,
+                                                gboolean      enabled,
+                                                gpointer      user_data)
+{
+  GtkActionMuxer *muxer = user_data;
+
+  gtk_action_muxer_action_enabled_changed (muxer, action_name, enabled);
+}
+
+static void
+gtk_action_muxer_action_state_changed (GtkActionMuxer *muxer,
+                                       const gchar    *action_name,
+                                       GVariant       *state)
+{
+  Action *action;
+  GSList *node;
+
+  action = g_hash_table_lookup (muxer->observed_actions, action_name);
+  for (node = action ? action->watchers : NULL; node; node = node->next)
+    gtk_action_observer_action_state_changed (node->data, GTK_ACTION_OBSERVABLE (muxer), action_name, state);
+  g_action_group_action_state_changed (G_ACTION_GROUP (muxer), action_name, state);
+}
+
+static void
+gtk_action_muxer_group_action_state_changed (GActionGroup *action_group,
+                                             const gchar  *action_name,
+                                             GVariant     *state,
+                                             gpointer      user_data)
+{
+  Group *group = user_data;
+  gchar *fullname;
+
+  fullname = g_strconcat (group->prefix, ".", action_name, NULL);
+  gtk_action_muxer_action_state_changed (group->muxer, fullname, state);
+
+  g_free (fullname);
+}
+
+static void
+gtk_action_muxer_parent_action_state_changed (GActionGroup *action_group,
+                                              const gchar  *action_name,
+                                              GVariant     *state,
+                                              gpointer      user_data)
+{
+  GtkActionMuxer *muxer = user_data;
+
+  gtk_action_muxer_action_state_changed (muxer, action_name, state);
+}
+
+static void
+gtk_action_muxer_action_added (GtkActionMuxer *muxer,
+                               const gchar    *action_name,
+                               GActionGroup   *original_group,
+                               const gchar    *orignal_action_name)
+{
+  const GVariantType *parameter_type;
+  gboolean enabled;
+  GVariant *state;
+  Action *action;
+
+  action = g_hash_table_lookup (muxer->observed_actions, action_name);
+
+  if (action && action->watchers &&
+      g_action_group_query_action (original_group, orignal_action_name,
+                                   &enabled, &parameter_type, NULL, NULL, &state))
+    {
+      GSList *node;
+
+      for (node = action->watchers; node; node = node->next)
+        gtk_action_observer_action_added (node->data,
+                                        GTK_ACTION_OBSERVABLE (muxer),
+                                        action_name, parameter_type, enabled, state);
+
+      if (state)
+        g_variant_unref (state);
+    }
+
+  g_action_group_action_added (G_ACTION_GROUP (muxer), action_name);
+}
+
+static void
+gtk_action_muxer_action_added_to_group (GActionGroup *action_group,
+                                        const gchar  *action_name,
+                                        gpointer      user_data)
+{
+  Group *group = user_data;
+  gchar *fullname;
+
+  fullname = g_strconcat (group->prefix, ".", action_name, NULL);
+  gtk_action_muxer_action_added (group->muxer, fullname, action_group, action_name);
+
+  g_free (fullname);
+}
+
+static void
+gtk_action_muxer_action_added_to_parent (GActionGroup *action_group,
+                                         const gchar  *action_name,
+                                         gpointer      user_data)
+{
+  GtkActionMuxer *muxer = user_data;
+
+  gtk_action_muxer_action_added (muxer, action_name, action_group, action_name);
+}
+
+static void
+gtk_action_muxer_action_removed (GtkActionMuxer *muxer,
+                                 const gchar    *action_name)
+{
+  Action *action;
+  GSList *node;
+
+  action = g_hash_table_lookup (muxer->observed_actions, action_name);
+  for (node = action ? action->watchers : NULL; node; node = node->next)
+    gtk_action_observer_action_removed (node->data, GTK_ACTION_OBSERVABLE (muxer), action_name);
+  g_action_group_action_removed (G_ACTION_GROUP (muxer), action_name);
+}
+
+static void
+gtk_action_muxer_action_removed_from_group (GActionGroup *action_group,
+                                            const gchar  *action_name,
+                                            gpointer      user_data)
+{
+  Group *group = user_data;
+  gchar *fullname;
+
+  fullname = g_strconcat (group->prefix, ".", action_name, NULL);
+  gtk_action_muxer_action_removed (group->muxer, fullname);
+
+  g_free (fullname);
+}
+
+static void
+gtk_action_muxer_action_removed_from_parent (GActionGroup *action_group,
+                                             const gchar  *action_name,
+                                             gpointer      user_data)
+{
+  GtkActionMuxer *muxer = user_data;
+
+  gtk_action_muxer_action_removed (muxer, action_name);
+}
+
+static gboolean
+gtk_action_muxer_query_action (GActionGroup        *action_group,
+                               const gchar         *action_name,
+                               gboolean            *enabled,
+                               const GVariantType **parameter_type,
+                               const GVariantType **state_type,
+                               GVariant           **state_hint,
+                               GVariant           **state)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (action_group);
+  Group *group;
+  const gchar *unprefixed_name;
+
+  group = gtk_action_muxer_find_group (muxer, action_name, &unprefixed_name);
+
+  if (group)
+    return g_action_group_query_action (group->group, unprefixed_name, enabled,
+                                        parameter_type, state_type, state_hint, state);
+
+  if (muxer->parent)
+    return g_action_group_query_action (G_ACTION_GROUP (muxer->parent), action_name,
+                                        enabled, parameter_type,
+                                        state_type, state_hint, state);
+
+  return FALSE;
+}
+
+static void
+gtk_action_muxer_activate_action (GActionGroup *action_group,
+                                  const gchar  *action_name,
+                                  GVariant     *parameter)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (action_group);
+  Group *group;
+  const gchar *unprefixed_name;
+
+  group = gtk_action_muxer_find_group (muxer, action_name, &unprefixed_name);
+
+  if (group)
+    g_action_group_activate_action (group->group, unprefixed_name, parameter);
+  else if (muxer->parent)
+    g_action_group_activate_action (G_ACTION_GROUP (muxer->parent), action_name, parameter);
+}
+
+static void
+gtk_action_muxer_change_action_state (GActionGroup *action_group,
+                                      const gchar  *action_name,
+                                      GVariant     *state)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (action_group);
+  Group *group;
+  const gchar *unprefixed_name;
+
+  group = gtk_action_muxer_find_group (muxer, action_name, &unprefixed_name);
+
+  if (group)
+    g_action_group_change_action_state (group->group, unprefixed_name, state);
+  else if (muxer->parent)
+    g_action_group_change_action_state (G_ACTION_GROUP (muxer->parent), action_name, state);
+}
+
+static void
+gtk_action_muxer_unregister_internal (Action   *action,
+                                      gpointer  observer)
+{
+  GtkActionMuxer *muxer = action->muxer;
+  GSList **ptr;
+
+  for (ptr = &action->watchers; *ptr; ptr = &(*ptr)->next)
+    if ((*ptr)->data == observer)
+      {
+        *ptr = g_slist_remove (*ptr, observer);
+
+        if (action->watchers == NULL)
+            g_hash_table_remove (muxer->observed_actions, action->fullname);
+
+        break;
+      }
+}
+
+static void
+gtk_action_muxer_weak_notify (gpointer  data,
+                              GObject  *where_the_object_was)
+{
+  Action *action = data;
+
+  gtk_action_muxer_unregister_internal (action, where_the_object_was);
+}
+
+static void
+gtk_action_muxer_register_observer (GtkActionObservable *observable,
+                                    const gchar         *name,
+                                    GtkActionObserver   *observer)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (observable);
+  Action *action;
+
+  action = g_hash_table_lookup (muxer->observed_actions, name);
+
+  if (action == NULL)
+    {
+      action = g_slice_new (Action);
+      action->muxer = muxer;
+      action->fullname = g_strdup (name);
+      action->watchers = NULL;
+
+      g_hash_table_insert (muxer->observed_actions, action->fullname, action);
+    }
+
+  action->watchers = g_slist_prepend (action->watchers, observer);
+  g_object_weak_ref (G_OBJECT (observer), gtk_action_muxer_weak_notify, action);
+}
+
+static void
+gtk_action_muxer_unregister_observer (GtkActionObservable *observable,
+                                      const gchar         *name,
+                                      GtkActionObserver   *observer)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (observable);
+  Action *action;
+
+  action = g_hash_table_lookup (muxer->observed_actions, name);
+  g_object_weak_unref (G_OBJECT (observer), gtk_action_muxer_weak_notify, action);
+  gtk_action_muxer_unregister_internal (action, observer);
+}
+
+static void
+gtk_action_muxer_free_group (gpointer data)
+{
+  Group *group = data;
+  gint i;
+
+  /* 'for loop' or 'four loop'? */
+  for (i = 0; i < 4; i++)
+    g_signal_handler_disconnect (group->group, group->handler_ids[i]);
+
+  g_object_unref (group->group);
+  g_free (group->prefix);
+
+  g_slice_free (Group, group);
+}
+
+static void
+gtk_action_muxer_free_action (gpointer data)
+{
+  Action *action = data;
+  GSList *it;
+
+  for (it = action->watchers; it; it = it->next)
+    g_object_weak_unref (G_OBJECT (it->data), gtk_action_muxer_weak_notify, action);
+
+  g_slist_free (action->watchers);
+  g_free (action->fullname);
+
+  g_slice_free (Action, action);
+}
+
+static void
+gtk_action_muxer_finalize (GObject *object)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (object);
+
+  g_assert_cmpint (g_hash_table_size (muxer->observed_actions), ==, 0);
+  g_hash_table_unref (muxer->observed_actions);
+  g_hash_table_unref (muxer->groups);
+
+  G_OBJECT_CLASS (gtk_action_muxer_parent_class)
+    ->finalize (object);
+}
+
+static void
+gtk_action_muxer_dispose (GObject *object)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (object);
+
+  if (muxer->parent)
+  {
+    g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_action_added_to_parent, muxer);
+    g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_action_removed_from_parent, muxer);
+    g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_parent_action_enabled_changed, muxer);
+    g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_parent_action_state_changed, muxer);
+
+    g_clear_object (&muxer->parent);
+  }
+
+  g_hash_table_remove_all (muxer->observed_actions);
+
+  G_OBJECT_CLASS (gtk_action_muxer_parent_class)
+    ->dispose (object);
+}
+
+static void
+gtk_action_muxer_get_property (GObject    *object,
+                               guint       property_id,
+                               GValue     *value,
+                               GParamSpec *pspec)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (object);
+
+  switch (property_id)
+    {
+    case PROP_PARENT:
+      g_value_set_object (value, gtk_action_muxer_get_parent (muxer));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    }
+}
+
+static void
+gtk_action_muxer_set_property (GObject      *object,
+                               guint         property_id,
+                               const GValue *value,
+                               GParamSpec   *pspec)
+{
+  GtkActionMuxer *muxer = GTK_ACTION_MUXER (object);
+
+  switch (property_id)
+    {
+    case PROP_PARENT:
+      gtk_action_muxer_set_parent (muxer, g_value_get_object (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    }
+}
+
+static void
+gtk_action_muxer_init (GtkActionMuxer *muxer)
+{
+  muxer->observed_actions = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, gtk_action_muxer_free_action);
+  muxer->groups = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, gtk_action_muxer_free_group);
+}
+
+static void
+gtk_action_muxer_observable_iface_init (GtkActionObservableInterface *iface)
+{
+  iface->register_observer = gtk_action_muxer_register_observer;
+  iface->unregister_observer = gtk_action_muxer_unregister_observer;
+}
+
+static void
+gtk_action_muxer_group_iface_init (GActionGroupInterface *iface)
+{
+  iface->list_actions = gtk_action_muxer_list_actions;
+  iface->query_action = gtk_action_muxer_query_action;
+  iface->activate_action = gtk_action_muxer_activate_action;
+  iface->change_action_state = gtk_action_muxer_change_action_state;
+}
+
+static void
+gtk_action_muxer_class_init (GObjectClass *class)
+{
+  class->get_property = gtk_action_muxer_get_property;
+  class->set_property = gtk_action_muxer_set_property;
+  class->finalize = gtk_action_muxer_finalize;
+  class->dispose = gtk_action_muxer_dispose;
+
+  properties[PROP_PARENT] = g_param_spec_object ("parent", "Parent",
+                                                 "The parent muxer",
+                                                 GTK_TYPE_ACTION_MUXER,
+                                                 G_PARAM_READWRITE |
+                                                 G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (class, NUM_PROPERTIES, properties);
+}
+
+/**
+ * gtk_action_muxer_insert:
+ * @muxer: a #GtkActionMuxer
+ * @prefix: the prefix string for the action group
+ * @action_group: a #GActionGroup
+ *
+ * Adds the actions in @action_group to the list of actions provided by
+ * @muxer.  @prefix is prefixed to each action name, such that for each
+ * action <varname>x</varname> in @action_group, there is an equivalent
+ * action @prefix<literal>.</literal><varname>x</varname> in @muxer.
+ *
+ * For example, if @prefix is "<literal>app</literal>" and @action_group
+ * contains an action called "<literal>quit</literal>", then @muxer will
+ * now contain an action called "<literal>app.quit</literal>".
+ *
+ * If any #GtkActionObservers are registered for actions in the group,
+ * "action_added" notifications will be emitted, as appropriate.
+ *
+ * @prefix must not contain a dot ('.').
+ */
+void
+gtk_action_muxer_insert (GtkActionMuxer *muxer,
+                         const gchar    *prefix,
+                         GActionGroup   *action_group)
+{
+  gchar **actions;
+  Group *group;
+  gint i;
+
+  /* TODO: diff instead of ripout and replace */
+  gtk_action_muxer_remove (muxer, prefix);
+
+  group = g_slice_new (Group);
+  group->muxer = muxer;
+  group->group = g_object_ref (action_group);
+  group->prefix = g_strdup (prefix);
+
+  g_hash_table_insert (muxer->groups, group->prefix, group);
+
+  actions = g_action_group_list_actions (group->group);
+  for (i = 0; actions[i]; i++)
+    gtk_action_muxer_action_added_to_group (group->group, actions[i], group);
+  g_strfreev (actions);
+
+  group->handler_ids[0] = g_signal_connect (group->group, "action-added",
+                                            G_CALLBACK (gtk_action_muxer_action_added_to_group), group);
+  group->handler_ids[1] = g_signal_connect (group->group, "action-removed",
+                                            G_CALLBACK (gtk_action_muxer_action_removed_from_group), group);
+  group->handler_ids[2] = g_signal_connect (group->group, "action-enabled-changed",
+                                            G_CALLBACK (gtk_action_muxer_group_action_enabled_changed), group);
+  group->handler_ids[3] = g_signal_connect (group->group, "action-state-changed",
+                                            G_CALLBACK (gtk_action_muxer_group_action_state_changed), group);
+}
+
+/**
+ * gtk_action_muxer_remove:
+ * @muxer: a #GtkActionMuxer
+ * @prefix: the prefix of the action group to remove
+ *
+ * Removes a #GActionGroup from the #GtkActionMuxer.
+ *
+ * If any #GtkActionObservers are registered for actions in the group,
+ * "action_removed" notifications will be emitted, as appropriate.
+ */
+void
+gtk_action_muxer_remove (GtkActionMuxer *muxer,
+                         const gchar    *prefix)
+{
+  Group *group;
+
+  group = g_hash_table_lookup (muxer->groups, prefix);
+
+  if (group != NULL)
+    {
+      gchar **actions;
+      gint i;
+
+      g_hash_table_steal (muxer->groups, prefix);
+
+      actions = g_action_group_list_actions (group->group);
+      for (i = 0; actions[i]; i++)
+        gtk_action_muxer_action_removed_from_group (group->group, actions[i], group);
+      g_strfreev (actions);
+
+      gtk_action_muxer_free_group (group);
+    }
+}
+
+/**
+ * gtk_action_muxer_new:
+ *
+ * Creates a new #GtkActionMuxer.
+ */
+GtkActionMuxer *
+gtk_action_muxer_new (void)
+{
+  return g_object_new (GTK_TYPE_ACTION_MUXER, NULL);
+}
+
+/**
+ * gtk_action_muxer_get_parent:
+ * @muxer: a #GtkActionMuxer
+ *
+ * Returns: (transfer none): the parent of @muxer, or NULL.
+ */
+GtkActionMuxer *
+gtk_action_muxer_get_parent (GtkActionMuxer *muxer)
+{
+  g_return_val_if_fail (GTK_IS_ACTION_MUXER (muxer), NULL);
+
+  return muxer->parent;
+}
+
+/**
+ * gtk_action_muxer_set_parent:
+ * @muxer: a #GtkActionMuxer
+ * @parent: (allow-none): the new parent #GtkActionMuxer
+ *
+ * Sets the parent of @muxer to @parent.
+ */
+void
+gtk_action_muxer_set_parent (GtkActionMuxer *muxer,
+                             GtkActionMuxer *parent)
+{
+  g_return_if_fail (GTK_IS_ACTION_MUXER (muxer));
+  g_return_if_fail (parent == NULL || GTK_IS_ACTION_MUXER (parent));
+
+  if (muxer->parent == parent)
+    return;
+
+  if (muxer->parent != NULL)
+    {
+      gchar **actions;
+      gchar **it;
+
+      actions = g_action_group_list_actions (G_ACTION_GROUP (muxer->parent));
+      for (it = actions; *it; it++)
+        gtk_action_muxer_action_removed (muxer, *it);
+      g_strfreev (actions);
+
+      g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_action_added_to_parent, muxer);
+      g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_action_removed_from_parent, muxer);
+      g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_parent_action_enabled_changed, muxer);
+      g_signal_handlers_disconnect_by_func (muxer->parent, gtk_action_muxer_parent_action_state_changed, muxer);
+
+      g_object_unref (muxer->parent);
+    }
+
+  muxer->parent = parent;
+
+  if (muxer->parent != NULL)
+    {
+      gchar **actions;
+      gchar **it;
+
+      g_object_ref (muxer->parent);
+
+      actions = g_action_group_list_actions (G_ACTION_GROUP (muxer->parent));
+      for (it = actions; *it; it++)
+        gtk_action_muxer_action_added (muxer, *it, G_ACTION_GROUP (muxer->parent), *it);
+      g_strfreev (actions);
+
+      g_signal_connect (muxer->parent, "action-added",
+                        G_CALLBACK (gtk_action_muxer_action_added_to_parent), muxer);
+      g_signal_connect (muxer->parent, "action-removed",
+                        G_CALLBACK (gtk_action_muxer_action_removed_from_parent), muxer);
+      g_signal_connect (muxer->parent, "action-enabled-changed",
+                        G_CALLBACK (gtk_action_muxer_parent_action_enabled_changed), muxer);
+      g_signal_connect (muxer->parent, "action-state-changed",
+                        G_CALLBACK (gtk_action_muxer_parent_action_state_changed), muxer);
+    }
+
+  g_object_notify_by_pspec (G_OBJECT (muxer), properties[PROP_PARENT]);
+}
diff --git a/libqmenumodel/src/gtk/gtkactionmuxer.h b/libqmenumodel/src/gtk/gtkactionmuxer.h
new file mode 100644
index 0000000..4014830
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkactionmuxer.h
@@ -0,0 +1,52 @@
+/*
+ * 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/>.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#ifndef __GTK_ACTION_MUXER_H__
+#define __GTK_ACTION_MUXER_H__
+
+#include <gio/gio.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_ACTION_MUXER                               (gtk_action_muxer_get_type ())
+#define GTK_ACTION_MUXER(inst)                              (G_TYPE_CHECK_INSTANCE_CAST ((inst),                     \
+                                                             GTK_TYPE_ACTION_MUXER, GtkActionMuxer))
+#define GTK_IS_ACTION_MUXER(inst)                           (G_TYPE_CHECK_INSTANCE_TYPE ((inst),                     \
+                                                             GTK_TYPE_ACTION_MUXER))
+
+typedef struct _GtkActionMuxer                              GtkActionMuxer;
+
+GType                   gtk_action_muxer_get_type                       (void);
+GtkActionMuxer *        gtk_action_muxer_new                            (void);
+
+void                    gtk_action_muxer_insert                         (GtkActionMuxer *muxer,
+                                                                         const gchar    *prefix,
+                                                                         GActionGroup   *action_group);
+
+void                    gtk_action_muxer_remove                         (GtkActionMuxer *muxer,
+                                                                         const gchar    *prefix);
+
+GtkActionMuxer *        gtk_action_muxer_get_parent                     (GtkActionMuxer *muxer);
+
+void                    gtk_action_muxer_set_parent                     (GtkActionMuxer *muxer,
+                                                                         GtkActionMuxer *parent);
+
+G_END_DECLS
+
+#endif /* __GTK_ACTION_MUXER_H__ */
diff --git a/libqmenumodel/src/gtk/gtkactionobservable.c b/libqmenumodel/src/gtk/gtkactionobservable.c
new file mode 100644
index 0000000..ab90df2
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkactionobservable.c
@@ -0,0 +1,78 @@
+/*
+ * 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 "gtkactionobservable.h"
+
+G_DEFINE_INTERFACE (GtkActionObservable, gtk_action_observable, G_TYPE_OBJECT)
+
+/*
+ * SECTION:gtkactionobserable
+ * @short_description: an interface implemented by objects that report
+ *                     changes to actions
+ */
+
+void
+gtk_action_observable_default_init (GtkActionObservableInterface *iface)
+{
+}
+
+/**
+ * gtk_action_observable_register_observer:
+ * @observable: a #GtkActionObservable
+ * @action_name: the name of the action
+ * @observer: the #GtkActionObserver to which the events will be reported
+ *
+ * Registers @observer as being interested in changes to @action_name on
+ * @observable.
+ */
+void
+gtk_action_observable_register_observer (GtkActionObservable *observable,
+                                         const gchar         *action_name,
+                                         GtkActionObserver   *observer)
+{
+  g_return_if_fail (GTK_IS_ACTION_OBSERVABLE (observable));
+
+  GTK_ACTION_OBSERVABLE_GET_IFACE (observable)
+    ->register_observer (observable, action_name, observer);
+}
+
+/**
+ * gtk_action_observable_unregister_observer:
+ * @observable: a #GtkActionObservable
+ * @action_name: the name of the action
+ * @observer: the #GtkActionObserver to which the events will be reported
+ *
+ * Removes the registration of @observer as being interested in changes
+ * to @action_name on @observable.
+ *
+ * If the observer was registered multiple times, it must be
+ * unregistered an equal number of times.
+ */
+void
+gtk_action_observable_unregister_observer (GtkActionObservable *observable,
+                                           const gchar         *action_name,
+                                           GtkActionObserver   *observer)
+{
+  g_return_if_fail (GTK_IS_ACTION_OBSERVABLE (observable));
+
+  GTK_ACTION_OBSERVABLE_GET_IFACE (observable)
+    ->unregister_observer (observable, action_name, observer);
+}
diff --git a/libqmenumodel/src/gtk/gtkactionobservable.h b/libqmenumodel/src/gtk/gtkactionobservable.h
new file mode 100644
index 0000000..aa1514b
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkactionobservable.h
@@ -0,0 +1,60 @@
+/*
+ * 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>
+ */
+
+#ifndef __GTK_ACTION_OBSERVABLE_H__
+#define __GTK_ACTION_OBSERVABLE_H__
+
+#include "gtkactionobserver.h"
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_ACTION_OBSERVABLE                          (gtk_action_observable_get_type ())
+#define GTK_ACTION_OBSERVABLE(inst)                         (G_TYPE_CHECK_INSTANCE_CAST ((inst),                     \
+                                                             GTK_TYPE_ACTION_OBSERVABLE, GtkActionObservable))
+#define GTK_IS_ACTION_OBSERVABLE(inst)                      (G_TYPE_CHECK_INSTANCE_TYPE ((inst),                     \
+                                                             GTK_TYPE_ACTION_OBSERVABLE))
+#define GTK_ACTION_OBSERVABLE_GET_IFACE(inst)               (G_TYPE_INSTANCE_GET_INTERFACE ((inst),                  \
+                                                             GTK_TYPE_ACTION_OBSERVABLE,                             \
+                                                             GtkActionObservableInterface))
+
+typedef struct _GtkActionObservableInterface                GtkActionObservableInterface;
+
+struct _GtkActionObservableInterface
+{
+  GTypeInterface g_iface;
+
+  void (* register_observer)   (GtkActionObservable *observable,
+                                const gchar         *action_name,
+                                GtkActionObserver   *observer);
+  void (* unregister_observer) (GtkActionObservable *observable,
+                                const gchar         *action_name,
+                                GtkActionObserver   *observer);
+};
+
+GType                   gtk_action_observable_get_type                  (void);
+void                    gtk_action_observable_register_observer         (GtkActionObservable *observable,
+                                                                         const gchar         *action_name,
+                                                                         GtkActionObserver   *observer);
+void                    gtk_action_observable_unregister_observer       (GtkActionObservable *observable,
+                                                                         const gchar         *action_name,
+                                                                         GtkActionObserver   *observer);
+
+G_END_DECLS
+
+#endif /* __GTK_ACTION_OBSERVABLE_H__ */
diff --git a/libqmenumodel/src/gtk/gtkactionobserver.c b/libqmenumodel/src/gtk/gtkactionobserver.c
new file mode 100644
index 0000000..cf70b20
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkactionobserver.c
@@ -0,0 +1,159 @@
+/*
+ * 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);
+}
diff --git a/libqmenumodel/src/gtk/gtkactionobserver.h b/libqmenumodel/src/gtk/gtkactionobserver.h
new file mode 100644
index 0000000..83629a7
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkactionobserver.h
@@ -0,0 +1,83 @@
+/*
+ * 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>
+ */
+
+#ifndef __GTK_ACTION_OBSERVER_H__
+#define __GTK_ACTION_OBSERVER_H__
+
+#include <gio/gio.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_ACTION_OBSERVER                            (gtk_action_observer_get_type ())
+#define GTK_ACTION_OBSERVER(inst)                           (G_TYPE_CHECK_INSTANCE_CAST ((inst),                     \
+                                                             GTK_TYPE_ACTION_OBSERVER, GtkActionObserver))
+#define GTK_IS_ACTION_OBSERVER(inst)                        (G_TYPE_CHECK_INSTANCE_TYPE ((inst),                     \
+                                                             GTK_TYPE_ACTION_OBSERVER))
+#define GTK_ACTION_OBSERVER_GET_IFACE(inst)                 (G_TYPE_INSTANCE_GET_INTERFACE ((inst),                  \
+                                                             GTK_TYPE_ACTION_OBSERVER, GtkActionObserverInterface))
+
+typedef struct _GtkActionObserverInterface                  GtkActionObserverInterface;
+typedef struct _GtkActionObservable                         GtkActionObservable;
+typedef struct _GtkActionObserver                           GtkActionObserver;
+
+struct _GtkActionObserverInterface
+{
+  GTypeInterface g_iface;
+
+  void (* action_added)           (GtkActionObserver    *observer,
+                                   GtkActionObservable  *observable,
+                                   const gchar          *action_name,
+                                   const GVariantType   *parameter_type,
+                                   gboolean              enabled,
+                                   GVariant             *state);
+  void (* action_enabled_changed) (GtkActionObserver    *observer,
+                                   GtkActionObservable  *observable,
+                                   const gchar          *action_name,
+                                   gboolean              enabled);
+  void (* action_state_changed)   (GtkActionObserver    *observer,
+                                   GtkActionObservable  *observable,
+                                   const gchar          *action_name,
+                                   GVariant             *state);
+  void (* action_removed)         (GtkActionObserver    *observer,
+                                   GtkActionObservable  *observable,
+                                   const gchar          *action_name);
+};
+
+GType                   gtk_action_observer_get_type                    (void);
+void                    gtk_action_observer_action_added                (GtkActionObserver   *observer,
+                                                                         GtkActionObservable *observable,
+                                                                         const gchar         *action_name,
+                                                                         const GVariantType  *parameter_type,
+                                                                         gboolean             enabled,
+                                                                         GVariant            *state);
+void                    gtk_action_observer_action_enabled_changed      (GtkActionObserver   *observer,
+                                                                         GtkActionObservable *observable,
+                                                                         const gchar         *action_name,
+                                                                         gboolean             enabled);
+void                    gtk_action_observer_action_state_changed        (GtkActionObserver   *observer,
+                                                                         GtkActionObservable *observable,
+                                                                         const gchar         *action_name,
+                                                                         GVariant            *state);
+void                    gtk_action_observer_action_removed              (GtkActionObserver   *observer,
+                                                                         GtkActionObservable *observable,
+                                                                         const gchar         *action_name);
+
+G_END_DECLS
+
+#endif /* __GTK_ACTION_OBSERVER_H__ */
diff --git a/libqmenumodel/src/gtk/gtkmenutracker.c b/libqmenumodel/src/gtk/gtkmenutracker.c
new file mode 100644
index 0000000..ab369ab
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkmenutracker.c
@@ -0,0 +1,495 @@
+/*
+ * Copyright © 2013 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, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#include "config.h"
+
+#include "gtkmenutracker.h"
+
+/**
+ * SECTION:gtkmenutracker
+ * @Title: GtkMenuTracker
+ * @Short_description: A helper class for interpreting #GMenuModel
+ *
+ * #GtkMenuTracker is a simple object to ease implementations of #GMenuModel.
+ * Given a #GtkActionObservable (usually a #GActionMuxer) along with a
+ * #GMenuModel, it will tell you which menu items to create and where to place
+ * them. If a menu item is removed, it will tell you the position of the menu
+ * item to remove.
+ *
+ * Using #GtkMenuTracker is fairly simple. The only guarantee you must make
+ * to #GtkMenuTracker is that you must obey all insert signals and track the
+ * position of items that #GtkMenuTracker gives you. That is, #GtkMenuTracker
+ * expects positions of all the latter items to change when it calls your
+ * insertion callback with an early position, as it may ask you to remove
+ * an item with a readjusted position later.
+ *
+ * #GtkMenuTracker will give you a #GtkMenuTrackerItem in your callback. You
+ * must hold onto this object until a remove signal is emitted. This item
+ * represents a single menu item, which can be one of three classes: normal item,
+ * separator, or submenu.
+ *
+ * Certain properties on the #GtkMenuTrackerItem are mutable, and you must
+ * listen for changes in the item. For more details, see the documentation
+ * for #GtkMenuTrackerItem along with https://live.gnome.org/GApplication/GMenuModel.
+ *
+ * The idea of @with_separators is for special cases where menu models may
+ * be tracked in places where separators are not available, like in toplevel
+ * "File", "Edit" menu bars. Ignoring separator items is wrong, as #GtkMenuTracker
+ * expects the position to change, so we must tell #GtkMenuTracker to ignore
+ * separators itself.
+ */
+
+typedef struct _GtkMenuTrackerSection GtkMenuTrackerSection;
+
+struct _GtkMenuTracker
+{
+  GtkActionObservable      *observable;
+  GtkMenuTrackerInsertFunc  insert_func;
+  GtkMenuTrackerRemoveFunc  remove_func;
+  gpointer                  user_data;
+
+  GtkMenuTrackerSection    *toplevel;
+};
+
+struct _GtkMenuTrackerSection
+{
+  GMenuModel *model;
+  GSList     *items;
+  gchar      *action_namespace;
+
+  guint       with_separators : 1;
+  guint       has_separator   : 1;
+
+  gulong      handler;
+};
+
+static GtkMenuTrackerSection *  gtk_menu_tracker_section_new    (GtkMenuTracker        *tracker,
+                                                                 GMenuModel            *model,
+                                                                 gboolean               with_separators,
+                                                                 gint                   offset,
+                                                                 const gchar           *action_namespace);
+static void                    gtk_menu_tracker_section_free    (GtkMenuTrackerSection *section);
+
+static GtkMenuTrackerSection *
+gtk_menu_tracker_section_find_model (GtkMenuTrackerSection *section,
+                                     GMenuModel            *model,
+                                     gint                  *offset)
+{
+  GSList *item;
+
+  if (section->has_separator)
+    (*offset)++;
+
+  if (section->model == model)
+    return section;
+
+  for (item = section->items; item; item = item->next)
+    {
+      GtkMenuTrackerSection *subsection = item->data;
+
+      if (subsection)
+        {
+          GtkMenuTrackerSection *found_section;
+
+          found_section = gtk_menu_tracker_section_find_model (subsection, model, offset);
+
+          if (found_section)
+            return found_section;
+        }
+      else
+        (*offset)++;
+    }
+
+  return FALSE;
+}
+
+/* this is responsible for syncing the showing of a separator for a
+ * single subsection (and its children).
+ *
+ * we only ever show separators if we have _actual_ children (ie: we do
+ * not show a separator if the section contains only empty child
+ * sections).  it's difficult to determine this on-the-fly, so we have
+ * this separate function to come back later and figure it out.
+ *
+ * 'section' is that section.
+ *
+ * 'tracker' is passed in so that we can emit callbacks when we decide
+ * to add/remove separators.
+ *
+ * 'offset' is passed in so we know which position to emit in our
+ * callbacks.  ie: if we add a separator right at the top of this
+ * section then we would emit it with this offset.  deeper inside, we
+ * adjust accordingly.
+ *
+ * could_have_separator is true in two situations:
+ *
+ *  - our parent section had with_separators defined and we are not the
+ *    first section (ie: we should add a separator if we have content in
+ *    order to divide us from the items above)
+ *
+ *  - if we had a 'label' attribute set for this section
+ *
+ * parent_model and parent_index are passed in so that we can give them
+ * to the insertion callback so that it can see the label (and anything
+ * else that happens to be defined on the section).
+ *
+ * we iterate each item in ourselves.  for subsections, we recursively
+ * run ourselves to sync separators.  after we are done, we notice if we
+ * have any items in us or if we are completely empty and sync if our
+ * separator is shown or not.
+ */
+static gint
+gtk_menu_tracker_section_sync_separators (GtkMenuTrackerSection *section,
+                                          GtkMenuTracker        *tracker,
+                                          gint                   offset,
+                                          gboolean               could_have_separator,
+                                          GMenuModel            *parent_model,
+                                          gint                   parent_index)
+{
+  gboolean should_have_separator;
+  gint n_items = 0;
+  GSList *item;
+  gint i = 0;
+
+  for (item = section->items; item; item = item->next)
+    {
+      GtkMenuTrackerSection *subsection = item->data;
+
+      if (subsection)
+        {
+          gboolean could_have_separator;
+
+          could_have_separator = (section->with_separators && i > 0) ||
+                                 g_menu_model_get_item_attribute (section->model, i, "label", "s", NULL);
+
+          n_items += gtk_menu_tracker_section_sync_separators (subsection, tracker, offset + n_items,
+                                                               could_have_separator, section->model, i);
+        }
+      else
+        n_items++;
+
+      i++;
+    }
+
+  should_have_separator = could_have_separator && n_items != 0;
+
+  if (should_have_separator > section->has_separator)
+    {
+      /* Add a separator */
+      GtkMenuTrackerItem *item;
+
+      item = _gtk_menu_tracker_item_new (tracker->observable, parent_model, parent_index, NULL, TRUE);
+      (* tracker->insert_func) (item, offset, tracker->user_data);
+      g_object_unref (item);
+
+      section->has_separator = TRUE;
+    }
+  else if (should_have_separator < section->has_separator)
+    {
+      /* Remove a separator */
+      (* tracker->remove_func) (offset, tracker->user_data);
+      section->has_separator = FALSE;
+    }
+
+  n_items += section->has_separator;
+
+  return n_items;
+}
+
+static gint
+gtk_menu_tracker_section_measure (GtkMenuTrackerSection *section)
+{
+  GSList *item;
+  gint n_items;
+
+  if (section == NULL)
+    return 1;
+
+  n_items = 0;
+
+  if (section->has_separator)
+    n_items++;
+
+  for (item = section->items; item; item = item->next)
+    n_items += gtk_menu_tracker_section_measure (item->data);
+
+  return n_items;
+}
+
+static void
+gtk_menu_tracker_remove_items (GtkMenuTracker  *tracker,
+                               GSList         **change_point,
+                               gint             offset,
+                               gint             n_items)
+{
+  gint i;
+
+  for (i = 0; i < n_items; i++)
+    {
+      GtkMenuTrackerSection *subsection;
+      gint n;
+
+      subsection = (*change_point)->data;
+      *change_point = g_slist_delete_link (*change_point, *change_point);
+
+      n = gtk_menu_tracker_section_measure (subsection);
+      gtk_menu_tracker_section_free (subsection);
+
+      while (n--)
+        (* tracker->remove_func) (offset, tracker->user_data);
+    }
+}
+
+static void
+gtk_menu_tracker_add_items (GtkMenuTracker         *tracker,
+                            GtkMenuTrackerSection  *section,
+                            GSList                **change_point,
+                            gint                    offset,
+                            GMenuModel             *model,
+                            gint                    position,
+                            gint                    n_items)
+{
+  while (n_items--)
+    {
+      GMenuModel *submenu;
+
+      submenu = g_menu_model_get_item_link (model, position + n_items, G_MENU_LINK_SECTION);
+      g_assert (submenu != model);
+      if (submenu != NULL)
+        {
+          GtkMenuTrackerSection *subsection;
+          gchar *action_namespace = NULL;
+
+          g_menu_model_get_item_attribute (model, position + n_items,
+                                           G_MENU_ATTRIBUTE_ACTION_NAMESPACE, "s", &action_namespace);
+
+          if (section->action_namespace)
+            {
+              gchar *namespace;
+
+              namespace = g_strjoin (".", section->action_namespace, action_namespace, NULL);
+              subsection = gtk_menu_tracker_section_new (tracker, submenu, FALSE, offset, namespace);
+              g_free (namespace);
+            }
+          else
+            subsection = gtk_menu_tracker_section_new (tracker, submenu, FALSE, offset, section->action_namespace);
+
+          *change_point = g_slist_prepend (*change_point, subsection);
+          g_free (action_namespace);
+          g_object_unref (submenu);
+        }
+      else
+        {
+          GtkMenuTrackerItem *item;
+
+          item = _gtk_menu_tracker_item_new (tracker->observable, model, position + n_items,
+                                             section->action_namespace, FALSE);
+          (* tracker->insert_func) (item, offset, tracker->user_data);
+          g_object_unref (item);
+
+          *change_point = g_slist_prepend (*change_point, NULL);
+        }
+    }
+}
+
+static void
+gtk_menu_tracker_model_changed (GMenuModel *model,
+                                gint        position,
+                                gint        removed,
+                                gint        added,
+                                gpointer    user_data)
+{
+  GtkMenuTracker *tracker = user_data;
+  GtkMenuTrackerSection *section;
+  GSList **change_point;
+  gint offset = 0;
+  gint i;
+
+  /* First find which section the changed model corresponds to, and the
+   * position of that section within the overall menu.
+   */
+  section = gtk_menu_tracker_section_find_model (tracker->toplevel, model, &offset);
+
+  /* Next, seek through that section to the change point.  This gives us
+   * the correct GSList** to make the change to and also finds the final
+   * offset at which we will make the changes (by measuring the number
+   * of items within each item of the section before the change point).
+   */
+  change_point = &section->items;
+  for (i = 0; i < position; i++)
+    {
+      offset += gtk_menu_tracker_section_measure ((*change_point)->data);
+      change_point = &(*change_point)->next;
+    }
+
+  /* We remove items in order and add items in reverse order.  This
+   * means that the offset used for all inserts and removes caused by a
+   * single change will be the same.
+   *
+   * This also has a performance advantage: GtkMenuShell stores the
+   * menu items in a linked list.  In the case where we are creating a
+   * menu for the first time, adding the items in reverse order means
+   * that we only ever insert at index zero, prepending the list.  This
+   * means that we can populate in O(n) time instead of O(n^2) that we
+   * would do by appending.
+   */
+  gtk_menu_tracker_remove_items (tracker, change_point, offset, removed);
+  gtk_menu_tracker_add_items (tracker, section, change_point, offset, model, position, added);
+
+  /* The offsets for insertion/removal of separators will be all over
+   * the place, however...
+   */
+  gtk_menu_tracker_section_sync_separators (tracker->toplevel, tracker, 0, FALSE, NULL, 0);
+}
+
+static void
+gtk_menu_tracker_section_free (GtkMenuTrackerSection *section)
+{
+  if (section == NULL)
+    return;
+
+  g_signal_handler_disconnect (section->model, section->handler);
+  g_slist_free_full (section->items, (GDestroyNotify) gtk_menu_tracker_section_free);
+  g_free (section->action_namespace);
+  g_object_unref (section->model);
+  g_slice_free (GtkMenuTrackerSection, section);
+}
+
+static GtkMenuTrackerSection *
+gtk_menu_tracker_section_new (GtkMenuTracker *tracker,
+                              GMenuModel     *model,
+                              gboolean        with_separators,
+                              gint            offset,
+                              const gchar    *action_namespace)
+{
+  GtkMenuTrackerSection *section;
+
+  section = g_slice_new0 (GtkMenuTrackerSection);
+  section->model = g_object_ref (model);
+  section->with_separators = with_separators;
+  section->action_namespace = g_strdup (action_namespace);
+
+  gtk_menu_tracker_add_items (tracker, section, &section->items, offset, model, 0, g_menu_model_get_n_items (model));
+  section->handler = g_signal_connect (model, "items-changed", G_CALLBACK (gtk_menu_tracker_model_changed), tracker);
+
+  return section;
+}
+
+/*< private >
+ * gtk_menu_tracker_new:
+ * @model: the model to flatten
+ * @with_separators: if the toplevel should have separators (ie: TRUE
+ *   for menus, FALSE for menubars)
+ * @action_namespace: the passed-in action namespace
+ * @insert_func: insert callback
+ * @remove_func: remove callback
+ * @user_data user data for callbacks
+ *
+ * Creates a GtkMenuTracker for @model, holding a ref on @model for as
+ * long as the tracker is alive.
+ *
+ * This flattens out the model, merging sections and inserting
+ * separators where appropriate.  It monitors for changes and performs
+ * updates on the fly.  It also handles action_namespace for subsections
+ * (but you will need to handle it yourself for submenus).
+ *
+ * When the tracker is first created, @insert_func will be called many
+ * times to populate the menu with the initial contents of @model
+ * (unless it is empty), before gtk_menu_tracker_new() returns.  For
+ * this reason, the menu that is using the tracker ought to be empty
+ * when it creates the tracker.
+ *
+ * Future changes to @model will result in more calls to @insert_func
+ * and @remove_func.
+ *
+ * The position argument to both functions is the linear 0-based
+ * position in the menu at which the item in question should be inserted
+ * or removed.
+ *
+ * For @insert_func, @model and @item_index are used to get the
+ * information about the menu item to insert.  @action_namespace is the
+ * action namespace that actions referred to from that item should place
+ * themselves in.  Note that if the item is a submenu and the
+ * "action-namespace" attribute is defined on the item, it will _not_ be
+ * applied to the @action_namespace argument as it is meant for the
+ * items inside of the submenu, not the submenu item itself.
+ *
+ * @is_separator is set to %TRUE in case the item being added is a
+ * separator.  @model and @item_index will still be meaningfully set in
+ * this case -- to the section menu item corresponding to the separator.
+ * This is useful if the section specifies a label, for example.  If
+ * there is an "action-namespace" attribute on this menu item then it
+ * should be ignored by the consumer because #GtkMenuTracker has already
+ * handled it.
+ *
+ * When using #GtkMenuTracker there is no need to hold onto @model or
+ * monitor it for changes.  The model will be unreffed when
+ * gtk_menu_tracker_free() is called.
+ */
+GtkMenuTracker *
+gtk_menu_tracker_new (GtkActionObservable      *observable,
+                      GMenuModel               *model,
+                      gboolean                  with_separators,
+                      const gchar              *action_namespace,
+                      GtkMenuTrackerInsertFunc  insert_func,
+                      GtkMenuTrackerRemoveFunc  remove_func,
+                      gpointer                  user_data)
+{
+  GtkMenuTracker *tracker;
+
+  tracker = g_slice_new (GtkMenuTracker);
+  tracker->observable = g_object_ref (observable);
+  tracker->insert_func = insert_func;
+  tracker->remove_func = remove_func;
+  tracker->user_data = user_data;
+
+  tracker->toplevel = gtk_menu_tracker_section_new (tracker, model, with_separators, 0, action_namespace);
+  gtk_menu_tracker_section_sync_separators (tracker->toplevel, tracker, 0, FALSE, NULL, 0);
+
+  return tracker;
+}
+
+GtkMenuTracker *
+gtk_menu_tracker_new_for_item_submenu (GtkMenuTrackerItem       *item,
+                                       GtkMenuTrackerInsertFunc  insert_func,
+                                       GtkMenuTrackerRemoveFunc  remove_func,
+                                       gpointer                  user_data)
+{
+  return gtk_menu_tracker_new (_gtk_menu_tracker_item_get_observable (item),
+                               _gtk_menu_tracker_item_get_submenu (item),
+                               TRUE,
+                               _gtk_menu_tracker_item_get_submenu_namespace (item),
+                               insert_func, remove_func, user_data);
+}
+
+/*< private >
+ * gtk_menu_tracker_free:
+ * @tracker: a #GtkMenuTracker
+ *
+ * Frees the tracker, ...
+ */
+void
+gtk_menu_tracker_free (GtkMenuTracker *tracker)
+{
+  gtk_menu_tracker_section_free (tracker->toplevel);
+  g_object_unref (tracker->observable);
+  g_slice_free (GtkMenuTracker, tracker);
+}
diff --git a/libqmenumodel/src/gtk/gtkmenutracker.h b/libqmenumodel/src/gtk/gtkmenutracker.h
new file mode 100644
index 0000000..96370ad
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkmenutracker.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright © 2013 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, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#ifndef __GTK_MENU_TRACKER_H__
+#define __GTK_MENU_TRACKER_H__
+
+#include "gtkmenutrackeritem.h"
+
+typedef struct _GtkMenuTracker GtkMenuTracker;
+
+typedef void         (* GtkMenuTrackerInsertFunc)                       (GtkMenuTrackerItem       *item,
+                                                                         gint                      position,
+                                                                         gpointer                  user_data);
+
+typedef void         (* GtkMenuTrackerRemoveFunc)                       (gint                      position,
+                                                                         gpointer                  user_data);
+
+
+GtkMenuTracker *        gtk_menu_tracker_new                            (GtkActionObservable      *observer,
+                                                                         GMenuModel               *model,
+                                                                         gboolean                  with_separators,
+                                                                         const gchar              *action_namespace,
+                                                                         GtkMenuTrackerInsertFunc  insert_func,
+                                                                         GtkMenuTrackerRemoveFunc  remove_func,
+                                                                         gpointer                  user_data);
+
+GtkMenuTracker *        gtk_menu_tracker_new_for_item_submenu           (GtkMenuTrackerItem       *item,
+                                                                         GtkMenuTrackerInsertFunc  insert_func,
+                                                                         GtkMenuTrackerRemoveFunc  remove_func,
+                                                                         gpointer                  user_data);
+
+void                    gtk_menu_tracker_free                           (GtkMenuTracker           *tracker);
+
+#endif /* __GTK_MENU_TRACKER_H__ */
diff --git a/libqmenumodel/src/gtk/gtkmenutrackeritem.c b/libqmenumodel/src/gtk/gtkmenutrackeritem.c
new file mode 100644
index 0000000..2d712a1
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkmenutrackeritem.c
@@ -0,0 +1,788 @@
+/*
+ * Copyright © 2013 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, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#include "config.h"
+
+#include "gtkmenutrackeritem.h"
+
+/**
+ * SECTION:gtkmenutrackeritem
+ * @Title: GtkMenuTrackerItem
+ * @Short_description: Small helper for model menu items
+ *
+ * A #GtkMenuTrackerItem is a small helper class used by #GtkMenuTracker to
+ * represent menu items. It has one of three classes: normal item, separator,
+ * or submenu.
+ *
+ * If an item is one of the non-normal classes (submenu, separator), only the
+ * label of the item needs to be respected. Otherwise, all the properties
+ * of the item contribute to the item's appearance and state.
+ *
+ * Implementing the appearance of the menu item is up to toolkits, and certain
+ * toolkits may choose to ignore certain properties, like icon or accel. The
+ * role of the item determines its accessibility role, along with its
+ * decoration if the GtkMenuTrackerItem::toggled property is true. As an
+ * example, if the item has the role %GTK_MENU_TRACKER_ITEM_ROLE_CHECK and
+ * GtkMenuTrackerItem::toggled is %FALSE, its accessible role should be that of
+ * a check menu item, and no decoration should be drawn. But if
+ * GtkMenuTrackerItem::toggled is %TRUE, a checkmark should be drawn.
+ *
+ * All properties except for the two class-determining properties,
+ * GtkMenuTrackerItem::is-separator and GtkMenuTrackerItem::has-submenu are
+ * allowed to change, so listen to the notify signals to update your item's
+ * appearance. When using a GObject library, this can conveniently be done
+ * with g_object_bind_property() and #GBinding, and this is how this is
+ * implemented in GTK+; the appearance side is implemented in #GtkModelMenuItem.
+ *
+ * When an item is clicked, simply call gtk_menu_tracker_item_activated() in
+ * response. The #GtkMenuTrackerItem will take care of everything related to
+ * activating the item and will itself update the state of all items in
+ * response.
+ *
+ * Submenus are a special case of menu item. When an item is a submenu, you
+ * should create a submenu for it with gtk_menu_tracker_new_item_for_submenu(),
+ * and apply the same menu tracking logic you would for a toplevel menu.
+ * Applications using submenus may want to lazily build their submenus in
+ * response to the user clicking on it, as building a submenu may be expensive.
+ *
+ * Thus, the submenu has two special controls -- the submenu's visibility
+ * should be controlled by the GtkMenuTrackerItem::submenu-shown property,
+ * and if a user clicks on the submenu, do not immediately show the menu,
+ * but call gtk_menu_tracker_item_request_submenu_shown() and wait for the
+ * GtkMenuTrackerItem::submenu-shown property to update. If the user navigates,
+ * the application may want to be notified so it can cancel the expensive
+ * operation that it was using to build the submenu. Thus,
+ * gtk_menu_tracker_item_request_submenu_shown() takes a boolean parameter.
+ * Use %TRUE when the user wants to open the submenu, and %FALSE when the
+ * user wants to close the submenu.
+ */
+
+typedef GObjectClass GtkMenuTrackerItemClass;
+
+struct _GtkMenuTrackerItem
+{
+  GObject parent_instance;
+
+  GtkActionObservable *observable;
+  gchar *action_namespace;
+  GMenuItem *item;
+  GtkMenuTrackerItemRole role : 4;
+  guint is_separator : 1;
+  guint can_activate : 1;
+  guint sensitive : 1;
+  guint toggled : 1;
+  guint submenu_shown : 1;
+  guint submenu_requested : 1;
+};
+
+enum {
+  PROP_0,
+  PROP_IS_SEPARATOR,
+  PROP_HAS_SUBMENU,
+  PROP_LABEL,
+  PROP_ICON,
+  PROP_SENSITIVE,
+  PROP_VISIBLE,
+  PROP_ROLE,
+  PROP_TOGGLED,
+  PROP_ACCEL,
+  PROP_SUBMENU_SHOWN,
+  N_PROPS
+};
+
+static GParamSpec *gtk_menu_tracker_item_pspecs[N_PROPS];
+
+static void gtk_menu_tracker_item_init_observer_iface (GtkActionObserverInterface *iface);
+G_DEFINE_TYPE_WITH_CODE (GtkMenuTrackerItem, gtk_menu_tracker_item, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_ACTION_OBSERVER, gtk_menu_tracker_item_init_observer_iface))
+
+GType
+gtk_menu_tracker_item_role_get_type (void)
+{
+  static gsize gtk_menu_tracker_item_role_type;
+
+  if (g_once_init_enter (&gtk_menu_tracker_item_role_type))
+    {
+      static const GEnumValue values[] = {
+        { GTK_MENU_TRACKER_ITEM_ROLE_NORMAL, "GTK_MENU_TRACKER_ITEM_ROLE_NORMAL", "normal" },
+        { GTK_MENU_TRACKER_ITEM_ROLE_CHECK, "GTK_MENU_TRACKER_ITEM_ROLE_CHECK", "check" },
+        { GTK_MENU_TRACKER_ITEM_ROLE_RADIO, "GTK_MENU_TRACKER_ITEM_ROLE_RADIO", "radio" },
+        { 0, NULL, NULL }
+      };
+      GType type;
+
+      type = g_enum_register_static ("GtkMenuTrackerItemRole", values);
+
+      g_once_init_leave (&gtk_menu_tracker_item_role_type, type);
+    }
+
+  return gtk_menu_tracker_item_role_type;
+}
+
+static void
+gtk_menu_tracker_item_get_property (GObject    *object,
+                                    guint       prop_id,
+                                    GValue     *value,
+                                    GParamSpec *pspec)
+{
+  GtkMenuTrackerItem *self = GTK_MENU_TRACKER_ITEM (object);
+
+  switch (prop_id)
+    {
+    case PROP_IS_SEPARATOR:
+      g_value_set_boolean (value, gtk_menu_tracker_item_get_is_separator (self));
+      break;
+    case PROP_HAS_SUBMENU:
+      g_value_set_boolean (value, gtk_menu_tracker_item_get_has_submenu (self));
+      break;
+    case PROP_LABEL:
+      g_value_set_string (value, gtk_menu_tracker_item_get_label (self));
+      break;
+    case PROP_ICON:
+      g_value_set_object (value, gtk_menu_tracker_item_get_icon (self));
+      break;
+    case PROP_SENSITIVE:
+      g_value_set_boolean (value, gtk_menu_tracker_item_get_sensitive (self));
+      break;
+    case PROP_VISIBLE:
+      g_value_set_boolean (value, gtk_menu_tracker_item_get_visible (self));
+      break;
+    case PROP_ROLE:
+      g_value_set_enum (value, gtk_menu_tracker_item_get_role (self));
+      break;
+    case PROP_TOGGLED:
+      g_value_set_boolean (value, gtk_menu_tracker_item_get_toggled (self));
+      break;
+    case PROP_ACCEL:
+      g_value_set_string (value, gtk_menu_tracker_item_get_accel (self));
+      break;
+    case PROP_SUBMENU_SHOWN:
+      g_value_set_boolean (value, gtk_menu_tracker_item_get_submenu_shown (self));
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gtk_menu_tracker_item_finalize (GObject *object)
+{
+  GtkMenuTrackerItem *self = GTK_MENU_TRACKER_ITEM (object);
+
+  g_free (self->action_namespace);
+
+  if (self->observable)
+    g_object_unref (self->observable);
+
+  g_object_unref (self->item);
+
+  G_OBJECT_CLASS (gtk_menu_tracker_item_parent_class)->finalize (object);
+}
+
+static void
+gtk_menu_tracker_item_init (GtkMenuTrackerItem * self)
+{
+}
+
+static void
+gtk_menu_tracker_item_class_init (GtkMenuTrackerItemClass *class)
+{
+  class->get_property = gtk_menu_tracker_item_get_property;
+  class->finalize = gtk_menu_tracker_item_finalize;
+
+  gtk_menu_tracker_item_pspecs[PROP_IS_SEPARATOR] =
+    g_param_spec_boolean ("is-separator", "", "", FALSE, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_HAS_SUBMENU] =
+    g_param_spec_boolean ("has-submenu", "", "", FALSE, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_LABEL] =
+    g_param_spec_string ("label", "", "", NULL, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_ICON] =
+    g_param_spec_object ("icon", "", "", G_TYPE_ICON, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_SENSITIVE] =
+    g_param_spec_boolean ("sensitive", "", "", FALSE, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_VISIBLE] =
+    g_param_spec_boolean ("visible", "", "", FALSE, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_ROLE] =
+    g_param_spec_enum ("role", "", "",
+                       GTK_TYPE_MENU_TRACKER_ITEM_ROLE, GTK_MENU_TRACKER_ITEM_ROLE_NORMAL,
+                       G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_TOGGLED] =
+    g_param_spec_boolean ("toggled", "", "", FALSE, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_ACCEL] =
+    g_param_spec_string ("accel", "", "", NULL, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+  gtk_menu_tracker_item_pspecs[PROP_SUBMENU_SHOWN] =
+    g_param_spec_boolean ("submenu-shown", "", "", FALSE, G_PARAM_STATIC_STRINGS | G_PARAM_READABLE);
+
+  g_object_class_install_properties (class, N_PROPS, gtk_menu_tracker_item_pspecs);
+}
+
+static void
+gtk_menu_tracker_item_action_added (GtkActionObserver   *observer,
+                                    GtkActionObservable *observable,
+                                    const gchar         *action_name,
+                                    const GVariantType  *parameter_type,
+                                    gboolean             enabled,
+                                    GVariant            *state)
+{
+  GtkMenuTrackerItem *self = GTK_MENU_TRACKER_ITEM (observer);
+  GVariant *action_target;
+
+  action_target = g_menu_item_get_attribute_value (self->item, G_MENU_ATTRIBUTE_TARGET, NULL);
+
+  self->can_activate = (action_target == NULL && parameter_type == NULL) ||
+                        (action_target != NULL && parameter_type != NULL &&
+                        g_variant_is_of_type (action_target, parameter_type));
+
+  if (!self->can_activate)
+    {
+      if (action_target)
+        g_variant_unref (action_target);
+      return;
+    }
+
+  self->sensitive = enabled;
+
+  if (action_target != NULL && state != NULL)
+    {
+      self->toggled = g_variant_equal (state, action_target);
+      self->role = GTK_MENU_TRACKER_ITEM_ROLE_RADIO;
+    }
+
+  else if (state != NULL && g_variant_is_of_type (state, G_VARIANT_TYPE_BOOLEAN))
+    {
+      self->toggled = g_variant_get_boolean (state);
+      self->role = GTK_MENU_TRACKER_ITEM_ROLE_CHECK;
+    }
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  if (self->sensitive)
+    g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_SENSITIVE]);
+
+  if (self->toggled)
+    g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_TOGGLED]);
+
+  if (self->role != GTK_MENU_TRACKER_ITEM_ROLE_NORMAL)
+    g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_ROLE]);
+
+  g_object_thaw_notify (G_OBJECT (self));
+
+  if (action_target)
+    g_variant_unref (action_target);
+}
+
+static void
+gtk_menu_tracker_item_action_enabled_changed (GtkActionObserver   *observer,
+                                              GtkActionObservable *observable,
+                                              const gchar         *action_name,
+                                              gboolean             enabled)
+{
+  GtkMenuTrackerItem *self = GTK_MENU_TRACKER_ITEM (observer);
+
+  if (!self->can_activate)
+    return;
+
+  if (self->sensitive == enabled)
+    return;
+
+  self->sensitive = enabled;
+
+  g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_SENSITIVE]);
+}
+
+static void
+gtk_menu_tracker_item_action_state_changed (GtkActionObserver   *observer,
+                                            GtkActionObservable *observable,
+                                            const gchar         *action_name,
+                                            GVariant            *state)
+{
+  GtkMenuTrackerItem *self = GTK_MENU_TRACKER_ITEM (observer);
+  GVariant *action_target;
+  gboolean was_toggled;
+
+  if (!self->can_activate)
+    return;
+
+  action_target = g_menu_item_get_attribute_value (self->item, G_MENU_ATTRIBUTE_TARGET, NULL);
+  was_toggled = self->toggled;
+
+  if (action_target)
+    {
+      self->toggled = g_variant_equal (state, action_target);
+      g_variant_unref (action_target);
+    }
+
+  else if (g_variant_is_of_type (state, G_VARIANT_TYPE_BOOLEAN))
+    self->toggled = g_variant_get_boolean (state);
+
+  else
+    self->toggled = FALSE;
+
+  if (self->toggled != was_toggled)
+    g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_TOGGLED]);
+}
+
+static void
+gtk_menu_tracker_item_action_removed (GtkActionObserver   *observer,
+                                      GtkActionObservable *observable,
+                                      const gchar         *action_name)
+{
+  GtkMenuTrackerItem *self = GTK_MENU_TRACKER_ITEM (observer);
+
+  if (!self->can_activate)
+    return;
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  if (self->sensitive)
+    {
+      self->sensitive = FALSE;
+      g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_SENSITIVE]);
+    }
+
+  if (self->toggled)
+    {
+      self->toggled = FALSE;
+      g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_TOGGLED]);
+    }
+
+  if (self->role != GTK_MENU_TRACKER_ITEM_ROLE_NORMAL)
+    {
+      self->role = GTK_MENU_TRACKER_ITEM_ROLE_NORMAL;
+      g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_ROLE]);
+    }
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+static void
+gtk_menu_tracker_item_init_observer_iface (GtkActionObserverInterface *iface)
+{
+  iface->action_added = gtk_menu_tracker_item_action_added;
+  iface->action_enabled_changed = gtk_menu_tracker_item_action_enabled_changed;
+  iface->action_state_changed = gtk_menu_tracker_item_action_state_changed;
+  iface->action_removed = gtk_menu_tracker_item_action_removed;
+}
+
+GtkMenuTrackerItem *
+_gtk_menu_tracker_item_new (GtkActionObservable *observable,
+                            GMenuModel          *model,
+                            gint                 item_index,
+                            const gchar         *action_namespace,
+                            gboolean             is_separator)
+{
+  GtkMenuTrackerItem *self;
+  const gchar *action_name;
+
+  g_return_val_if_fail (GTK_IS_ACTION_OBSERVABLE (observable), NULL);
+  g_return_val_if_fail (G_IS_MENU_MODEL (model), NULL);
+
+  self = g_object_new (GTK_TYPE_MENU_TRACKER_ITEM, NULL);
+  self->item = g_menu_item_new_from_model (model, item_index);
+  self->action_namespace = g_strdup (action_namespace);
+  self->observable = g_object_ref (observable);
+  self->is_separator = is_separator;
+
+  if (!is_separator && g_menu_item_get_attribute (self->item, "action", "&s", &action_name))
+    {
+      GActionGroup *group = G_ACTION_GROUP (observable);
+      const GVariantType *parameter_type;
+      gboolean enabled;
+      GVariant *state;
+      gboolean found;
+
+      state = NULL;
+
+      if (action_namespace)
+        {
+          gchar *full_action;
+
+          full_action = g_strjoin (".", action_namespace, action_name, NULL);
+          gtk_action_observable_register_observer (self->observable, full_action, GTK_ACTION_OBSERVER (self));
+          found = g_action_group_query_action (group, full_action, &enabled, &parameter_type, NULL, NULL, &state);
+          g_free (full_action);
+        }
+      else
+        {
+          gtk_action_observable_register_observer (self->observable, action_name, GTK_ACTION_OBSERVER (self));
+          found = g_action_group_query_action (group, action_name, &enabled, &parameter_type, NULL, NULL, &state);
+        }
+
+      if (found)
+        gtk_menu_tracker_item_action_added (GTK_ACTION_OBSERVER (self), observable, NULL, parameter_type, enabled, state);
+      else
+        gtk_menu_tracker_item_action_removed (GTK_ACTION_OBSERVER (self), observable, NULL);
+
+      if (state)
+        g_variant_unref (state);
+    }
+  else
+    self->sensitive = TRUE;
+
+  return self;
+}
+
+GtkActionObservable *
+_gtk_menu_tracker_item_get_observable (GtkMenuTrackerItem *self)
+{
+  return self->observable;
+}
+
+/**
+ * gtk_menu_tracker_item_get_is_separator:
+ * @self: A #GtkMenuTrackerItem instance
+ *
+ * Returns whether the menu item is a separator. If so, only
+ * certain properties may need to be obeyed. See the documentation
+ * for #GtkMenuTrackerItem.
+ */
+gboolean
+gtk_menu_tracker_item_get_is_separator (GtkMenuTrackerItem *self)
+{
+  return self->is_separator;
+}
+
+/**
+ * gtk_menu_tracker_item_get_has_submenu:
+ * @self: A #GtkMenuTrackerItem instance
+ *
+ * Returns whether the menu item has a submenu. If so, only
+ * certain properties may need to be obeyed. See the documentation
+ * for #GtkMenuTrackerItem.
+ */
+gboolean
+gtk_menu_tracker_item_get_has_submenu (GtkMenuTrackerItem *self)
+{
+  GMenuModel *link;
+
+  link = g_menu_item_get_link (self->item, G_MENU_LINK_SUBMENU);
+
+  if (link)
+    {
+      g_object_unref (link);
+      return TRUE;
+    }
+  else
+    return FALSE;
+}
+
+const gchar *
+gtk_menu_tracker_item_get_label (GtkMenuTrackerItem *self)
+{
+  const gchar *label = NULL;
+
+  g_menu_item_get_attribute (self->item, G_MENU_ATTRIBUTE_LABEL, "&s", &label);
+
+  return label;
+}
+
+/**
+ * gtk_menu_tracker_item_get_icon:
+ *
+ * Returns: (transfer full):
+ */
+GIcon *
+gtk_menu_tracker_item_get_icon (GtkMenuTrackerItem *self)
+{
+  GVariant *icon_data;
+  GIcon *icon;
+
+  icon_data = g_menu_item_get_attribute_value (self->item, "icon", NULL);
+
+  if (icon_data == NULL)
+    return NULL;
+
+  icon = g_icon_deserialize (icon_data);
+  g_variant_unref (icon_data);
+
+  return icon;
+}
+
+gboolean
+gtk_menu_tracker_item_get_sensitive (GtkMenuTrackerItem *self)
+{
+  return self->sensitive;
+}
+
+gboolean
+gtk_menu_tracker_item_get_visible (GtkMenuTrackerItem *self)
+{
+  return TRUE;
+}
+
+GtkMenuTrackerItemRole
+gtk_menu_tracker_item_get_role (GtkMenuTrackerItem *self)
+{
+  return self->role;
+}
+
+gboolean
+gtk_menu_tracker_item_get_toggled (GtkMenuTrackerItem *self)
+{
+  return self->toggled;
+}
+
+const gchar *
+gtk_menu_tracker_item_get_accel (GtkMenuTrackerItem *self)
+{
+  const gchar *accel = NULL;
+
+  g_menu_item_get_attribute (self->item, "accel", "&s", &accel);
+
+  return accel;
+}
+
+GMenuModel *
+_gtk_menu_tracker_item_get_submenu (GtkMenuTrackerItem *self)
+{
+  return g_menu_item_get_link (self->item, "submenu");
+}
+
+gchar *
+_gtk_menu_tracker_item_get_submenu_namespace (GtkMenuTrackerItem *self)
+{
+  const gchar *namespace;
+
+  if (g_menu_item_get_attribute (self->item, "action-namespace", "&s", &namespace))
+    {
+      if (self->action_namespace)
+        return g_strjoin (".", self->action_namespace, namespace, NULL);
+      else
+        return g_strdup (namespace);
+    }
+  else
+    return g_strdup (self->action_namespace);
+}
+
+gboolean
+gtk_menu_tracker_item_get_should_request_show (GtkMenuTrackerItem *self)
+{
+  return g_menu_item_get_attribute (self->item, "submenu-action", "&s", NULL);
+}
+
+gboolean
+gtk_menu_tracker_item_get_submenu_shown (GtkMenuTrackerItem *self)
+{
+  return self->submenu_shown;
+}
+
+static void
+gtk_menu_tracker_item_set_submenu_shown (GtkMenuTrackerItem *self,
+                                         gboolean            submenu_shown)
+{
+  if (submenu_shown == self->submenu_shown)
+    return;
+
+  self->submenu_shown = submenu_shown;
+  g_object_notify_by_pspec (G_OBJECT (self), gtk_menu_tracker_item_pspecs[PROP_SUBMENU_SHOWN]);
+}
+
+void
+gtk_menu_tracker_item_activated (GtkMenuTrackerItem *self)
+{
+  const gchar *action_name;
+  GVariant *action_target;
+
+  g_return_if_fail (GTK_IS_MENU_TRACKER_ITEM (self));
+
+  if (!self->can_activate)
+    return;
+
+  g_menu_item_get_attribute (self->item, G_MENU_ATTRIBUTE_ACTION, "&s", &action_name);
+  action_target = g_menu_item_get_attribute_value (self->item, G_MENU_ATTRIBUTE_TARGET, NULL);
+
+  if (self->action_namespace)
+    {
+      gchar *full_action;
+
+      full_action = g_strjoin (".", self->action_namespace, action_name, NULL);
+      g_action_group_activate_action (G_ACTION_GROUP (self->observable), full_action, action_target);
+      g_free (full_action);
+    }
+  else
+    g_action_group_activate_action (G_ACTION_GROUP (self->observable), action_name, action_target);
+
+  if (action_target)
+    g_variant_unref (action_target);
+}
+
+typedef struct
+{
+  GtkMenuTrackerItem *item;
+  gchar              *submenu_action;
+  gboolean            first_time;
+} GtkMenuTrackerOpener;
+
+static void
+gtk_menu_tracker_opener_update (GtkMenuTrackerOpener *opener)
+{
+  GActionGroup *group = G_ACTION_GROUP (opener->item->observable);
+  gboolean is_open = TRUE;
+
+  /* We consider the menu as being "open" if the action does not exist
+   * or if there is another problem (no state, wrong state type, etc.).
+   * If the action exists, with the correct state then we consider it
+   * open if we have ever seen this state equal to TRUE.
+   *
+   * In the event that we see the state equal to FALSE, we force it back
+   * to TRUE.  We do not signal that the menu was closed because this is
+   * likely to create UI thrashing.
+   *
+   * The only way the menu can have a true-to-false submenu-shown
+   * transition is if the user calls _request_submenu_shown (FALSE).
+   * That is handled in _free() below.
+   */
+
+  if (g_action_group_has_action (group, opener->submenu_action))
+    {
+      GVariant *state = g_action_group_get_action_state (group, opener->submenu_action);
+
+      if (state)
+        {
+          if (g_variant_is_of_type (state, G_VARIANT_TYPE_BOOLEAN))
+            is_open = g_variant_get_boolean (state);
+          g_variant_unref (state);
+        }
+    }
+
+  /* If it is already open, signal that.
+   *
+   * If it is not open, ask it to open.
+   */
+  if (is_open)
+    gtk_menu_tracker_item_set_submenu_shown (opener->item, TRUE);
+
+  if (!is_open || opener->first_time)
+    {
+      g_action_group_change_action_state (group, opener->submenu_action, g_variant_new_boolean (TRUE));
+      opener->first_time = FALSE;
+    }
+}
+
+static void
+gtk_menu_tracker_opener_added (GActionGroup *group,
+                               const gchar  *action_name,
+                               gpointer      user_data)
+{
+  GtkMenuTrackerOpener *opener = user_data;
+
+  if (g_str_equal (action_name, opener->submenu_action))
+    gtk_menu_tracker_opener_update (opener);
+}
+
+static void
+gtk_menu_tracker_opener_removed (GActionGroup *action_group,
+                                 const gchar  *action_name,
+                                 gpointer      user_data)
+{
+  GtkMenuTrackerOpener *opener = user_data;
+
+  if (g_str_equal (action_name, opener->submenu_action))
+    gtk_menu_tracker_opener_update (opener);
+}
+
+static void
+gtk_menu_tracker_opener_changed (GActionGroup *action_group,
+                                 const gchar  *action_name,
+                                 GVariant     *new_state,
+                                 gpointer      user_data)
+{
+  GtkMenuTrackerOpener *opener = user_data;
+
+  if (g_str_equal (action_name, opener->submenu_action))
+    gtk_menu_tracker_opener_update (opener);
+}
+
+static void
+gtk_menu_tracker_opener_free (gpointer data)
+{
+  GtkMenuTrackerOpener *opener = data;
+
+  g_signal_handlers_disconnect_by_func (opener->item->observable, gtk_menu_tracker_opener_added, opener);
+  g_signal_handlers_disconnect_by_func (opener->item->observable, gtk_menu_tracker_opener_removed, opener);
+  g_signal_handlers_disconnect_by_func (opener->item->observable, gtk_menu_tracker_opener_changed, opener);
+
+  g_action_group_change_action_state (G_ACTION_GROUP (opener->item->observable),
+                                      opener->submenu_action,
+                                      g_variant_new_boolean (FALSE));
+
+  gtk_menu_tracker_item_set_submenu_shown (opener->item, FALSE);
+
+  g_free (opener->submenu_action);
+
+  g_slice_free (GtkMenuTrackerOpener, opener);
+}
+
+static GtkMenuTrackerOpener *
+gtk_menu_tracker_opener_new (GtkMenuTrackerItem *item,
+                             const gchar        *submenu_action)
+{
+  GtkMenuTrackerOpener *opener;
+
+  opener = g_slice_new (GtkMenuTrackerOpener);
+  opener->first_time = TRUE;
+  opener->item = item;
+
+  if (item->action_namespace)
+    opener->submenu_action = g_strjoin (".", item->action_namespace, submenu_action, NULL);
+  else
+    opener->submenu_action = g_strdup (submenu_action);
+
+  g_signal_connect (item->observable, "action-added", G_CALLBACK (gtk_menu_tracker_opener_added), opener);
+  g_signal_connect (item->observable, "action-removed", G_CALLBACK (gtk_menu_tracker_opener_removed), opener);
+  g_signal_connect (item->observable, "action-state-changed", G_CALLBACK (gtk_menu_tracker_opener_changed), opener);
+
+  gtk_menu_tracker_opener_update (opener);
+
+  return opener;
+}
+
+void
+gtk_menu_tracker_item_request_submenu_shown (GtkMenuTrackerItem *self,
+                                             gboolean            shown)
+{
+  const gchar *submenu_action;
+  gboolean has_submenu_action;
+
+  if (shown == self->submenu_requested)
+    return;
+
+  has_submenu_action = g_menu_item_get_attribute (self->item, "submenu-action", "&s", &submenu_action);
+
+  self->submenu_requested = shown;
+
+  /* If we have a submenu action, start a submenu opener and wait
+   * for the reply from the client. Otherwise, simply open the
+   * submenu immediately.
+   */
+  if (has_submenu_action)
+    {
+      if (shown)
+        g_object_set_data_full (G_OBJECT (self), "submenu-opener",
+                                gtk_menu_tracker_opener_new (self, submenu_action),
+                                gtk_menu_tracker_opener_free);
+      else
+        g_object_set_data (G_OBJECT (self), "submenu-opener", NULL);
+    }
+  else
+    gtk_menu_tracker_item_set_submenu_shown (self, shown);
+}
diff --git a/libqmenumodel/src/gtk/gtkmenutrackeritem.h b/libqmenumodel/src/gtk/gtkmenutrackeritem.h
new file mode 100644
index 0000000..9db30eb
--- /dev/null
+++ b/libqmenumodel/src/gtk/gtkmenutrackeritem.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright © 2011, 2013 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/>.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#ifndef __GTK_MENU_TRACKER_ITEM_H__
+#define __GTK_MENU_TRACKER_ITEM_H__
+
+#include "gtkactionobservable.h"
+
+#define GTK_TYPE_MENU_TRACKER_ITEM                          (gtk_menu_tracker_item_get_type ())
+#define GTK_MENU_TRACKER_ITEM(inst)                         (G_TYPE_CHECK_INSTANCE_CAST ((inst), \
+                                                             GTK_TYPE_MENU_TRACKER_ITEM, GtkMenuTrackerItem))
+#define GTK_IS_MENU_TRACKER_ITEM(inst)                      (G_TYPE_CHECK_INSTANCE_TYPE ((inst), \
+                                                             GTK_TYPE_MENU_TRACKER_ITEM))
+
+typedef struct _GtkMenuTrackerItem GtkMenuTrackerItem;
+
+#define GTK_TYPE_MENU_TRACKER_ITEM_ROLE                     (gtk_menu_tracker_item_role_get_type ())
+
+typedef enum  {
+  GTK_MENU_TRACKER_ITEM_ROLE_NORMAL,
+  GTK_MENU_TRACKER_ITEM_ROLE_CHECK,
+  GTK_MENU_TRACKER_ITEM_ROLE_RADIO,
+} GtkMenuTrackerItemRole;
+
+GType                   gtk_menu_tracker_item_get_type                  (void) G_GNUC_CONST;
+
+GType                   gtk_menu_tracker_item_role_get_type             (void) G_GNUC_CONST;
+
+GtkMenuTrackerItem *   _gtk_menu_tracker_item_new                       (GtkActionObservable *observable,
+                                                                         GMenuModel          *model,
+                                                                         gint                 item_index,
+                                                                         const gchar         *action_namespace,
+                                                                         gboolean             is_separator);
+
+GtkActionObservable *  _gtk_menu_tracker_item_get_observable            (GtkMenuTrackerItem *self);
+
+gboolean                gtk_menu_tracker_item_get_is_separator          (GtkMenuTrackerItem *self);
+
+gboolean                gtk_menu_tracker_item_get_has_submenu           (GtkMenuTrackerItem *self);
+
+const gchar *           gtk_menu_tracker_item_get_label                 (GtkMenuTrackerItem *self);
+
+GIcon *                 gtk_menu_tracker_item_get_icon                  (GtkMenuTrackerItem *self);
+
+gboolean                gtk_menu_tracker_item_get_sensitive             (GtkMenuTrackerItem *self);
+
+gboolean                gtk_menu_tracker_item_get_visible               (GtkMenuTrackerItem *self);
+
+GtkMenuTrackerItemRole  gtk_menu_tracker_item_get_role                  (GtkMenuTrackerItem *self);
+
+gboolean                gtk_menu_tracker_item_get_toggled               (GtkMenuTrackerItem *self);
+
+const gchar *           gtk_menu_tracker_item_get_accel                 (GtkMenuTrackerItem *self);
+
+GMenuModel *           _gtk_menu_tracker_item_get_submenu               (GtkMenuTrackerItem *self);
+
+gchar *                _gtk_menu_tracker_item_get_submenu_namespace     (GtkMenuTrackerItem *self);
+
+gboolean                gtk_menu_tracker_item_get_should_request_show   (GtkMenuTrackerItem *self);
+
+void                    gtk_menu_tracker_item_activated                 (GtkMenuTrackerItem *self);
+
+void                    gtk_menu_tracker_item_request_submenu_shown     (GtkMenuTrackerItem *self,
+                                                                         gboolean            shown);
+
+gboolean                gtk_menu_tracker_item_get_submenu_shown         (GtkMenuTrackerItem *self);
+
+#endif
diff --git a/libqmenumodel/src/unitymenumodel.cpp b/libqmenumodel/src/unitymenumodel.cpp
new file mode 100644
index 0000000..25df10b
--- /dev/null
+++ b/libqmenumodel/src/unitymenumodel.cpp
@@ -0,0 +1,227 @@
+/*
+ * Copyright 2013 Canonical Ltd.
+ *
+ * This program 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; version 3.
+ *
+ * This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Lars Uebernickel <lars.uebernickel@canonical.com>
+ */
+
+#include "unitymenumodel.h"
+
+extern "C" {
+  #include "gtk/gtkactionmuxer.h"
+  #include "gtk/gtkmenutracker.h"
+}
+
+G_DEFINE_QUARK (UNITY_MENU_MODEL, unity_menu_model)
+
+class UnityMenuModelPrivate
+{
+public:
+    UnityMenuModelPrivate(UnityMenuModel *model,
+                          const QByteArray &busName,
+                          const QByteArray &actionGroupObjectPath,
+                          const QByteArray &menuObjectPath);
+
+    ~UnityMenuModelPrivate();
+
+    int nrItems();
+    QVariant data(int position, int role);
+
+private:
+    UnityMenuModel *model;
+    GtkActionMuxer *muxer;
+    GtkMenuTracker *menutracker;
+    GSequence *items;
+
+    static void menuItemInserted(GtkMenuTrackerItem *item, gint position, gpointer user_data);
+    static void menuItemRemoved(gint position, gpointer user_data);
+    static void menuItemChanged(GObject *object, GParamSpec *pspec, gpointer user_data);
+};
+
+UnityMenuModelPrivate::UnityMenuModelPrivate(UnityMenuModel *model,
+                                             const QByteArray &busName,
+                                             const QByteArray &actionGroupObjectPath,
+                                             const QByteArray &menuObjectPath)
+{
+    GDBusConnection *connection;
+    GDBusActionGroup *actions;
+    GDBusMenuModel *menu;
+
+    this->model = model;
+
+    connection = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, NULL);
+    actions = g_dbus_action_group_get (connection, busName.constData(), actionGroupObjectPath.constData());
+    menu = g_dbus_menu_model_get (connection, busName.constData(), menuObjectPath.constData());
+
+    this->muxer = gtk_action_muxer_new ();
+    g_object_set_qdata (G_OBJECT (this->muxer), unity_menu_model_quark (), model);
+    gtk_action_muxer_insert (this->muxer, "indicator", G_ACTION_GROUP (actions));
+
+    this->menutracker = gtk_menu_tracker_new (GTK_ACTION_OBSERVABLE (this->muxer),
+                                              G_MENU_MODEL (menu), TRUE, "indicator",
+                                              menuItemInserted, menuItemRemoved, this);
+
+    this->items = g_sequence_new (NULL);
+
+    g_object_unref (menu);
+    g_object_unref (actions);
+    g_object_unref (connection);
+}
+
+UnityMenuModelPrivate::~UnityMenuModelPrivate()
+{
+    GSequenceIter *it;
+
+    it = g_sequence_get_begin_iter (this->items);
+    while (!g_sequence_iter_is_end (it)) {
+        GtkMenuTrackerItem *item = (GtkMenuTrackerItem *) g_sequence_get (it);
+        g_signal_handlers_disconnect_by_func (item, (gpointer) menuItemChanged, it);
+        g_object_unref (item);
+        it = g_sequence_iter_next (it);
+    }
+    g_sequence_free (this->items);
+
+    g_object_unref (this->muxer);
+    gtk_menu_tracker_free (this->menutracker);
+}
+
+int UnityMenuModelPrivate::nrItems()
+{
+    return g_sequence_get_length (this->items);
+}
+
+QVariant UnityMenuModelPrivate::data(int position, int role)
+{
+    GtkMenuTrackerItem *item;
+
+    item = (GtkMenuTrackerItem *) g_sequence_get (g_sequence_get_iter_at_pos (this->items, position));
+
+    switch (role) {
+        case UnityMenuModel::LabelRole:
+            return gtk_menu_tracker_item_get_label (item);
+
+        case UnityMenuModel::SensitiveRole:
+            return gtk_menu_tracker_item_get_sensitive (item);
+
+        default:
+            return QVariant();
+    }
+}
+
+void UnityMenuModelPrivate::menuItemInserted(GtkMenuTrackerItem *item, gint position, gpointer user_data)
+{
+    UnityMenuModelPrivate *priv = (UnityMenuModelPrivate *)user_data;
+    GSequenceIter *it;
+
+    priv->model->beginInsertRows(QModelIndex(), position, position);
+
+    it = g_sequence_get_iter_at_pos (priv->items, position);
+    g_signal_connect (item, "notify", G_CALLBACK (menuItemChanged), it);
+    g_sequence_insert_before (it, g_object_ref (item));
+
+    priv->model->endInsertRows();
+}
+
+void UnityMenuModelPrivate::menuItemRemoved(gint position, gpointer user_data)
+{
+    UnityMenuModelPrivate *priv = (UnityMenuModelPrivate *)user_data;
+    GSequenceIter *it;
+    GtkMenuTrackerItem *item;
+
+    priv->model->beginRemoveRows(QModelIndex(), position, position);
+
+    it = g_sequence_get_iter_at_pos (priv->items, position);
+    item = (GtkMenuTrackerItem *) g_sequence_get (it);
+    g_signal_handlers_disconnect_by_func (item, (gpointer) menuItemChanged, it);
+    g_object_unref (item);
+    g_sequence_remove (it);
+
+    priv->model->endRemoveRows();
+}
+
+void UnityMenuModelPrivate::menuItemChanged(GObject *object, GParamSpec *pspec, gpointer user_data)
+{
+    GSequenceIter *it = (GSequenceIter *) user_data;
+    GtkMenuTrackerItem *item;
+    GtkActionObservable *muxer;
+    UnityMenuModel *model;
+    gint position;
+
+    item = (GtkMenuTrackerItem *) g_sequence_get (it);
+    muxer = _gtk_menu_tracker_item_get_observable (item);
+    model = (UnityMenuModel *) g_object_get_qdata (G_OBJECT (muxer), unity_menu_model_quark ());
+    position = g_sequence_iter_get_position (it);
+
+    Q_EMIT model->dataChanged(model->index(position, 0), model->index(position, 0));
+}
+
+UnityMenuModel::UnityMenuModel(QObject *parent):
+    QAbstractListModel(parent)
+{
+}
+
+UnityMenuModel::UnityMenuModel(const QByteArray &busName,
+                               const QByteArray &actionGroupObjectPath,
+                               const QByteArray &menuObjectPath,
+                               QObject *parent):
+    QAbstractListModel(parent),
+    priv(NULL)
+{
+}
+
+void UnityMenuModel::init(const QByteArray &busName, const QByteArray &actionGroupObjectPath, const QByteArray &menuObjectPath)
+{
+    priv = new UnityMenuModelPrivate (this, busName, actionGroupObjectPath, menuObjectPath);
+}
+
+UnityMenuModel::~UnityMenuModel()
+{
+    delete priv;
+}
+
+int UnityMenuModel::rowCount(const QModelIndex &parent) const
+{
+    return priv && !parent.isValid() ? priv->nrItems() : 0;
+}
+
+int UnityMenuModel::columnCount(const QModelIndex &parent) const
+{
+    return 1;
+}
+
+QVariant UnityMenuModel::data(const QModelIndex &index, int role) const
+{
+    return priv ? priv->data(index.row(), role) : QVariant();
+}
+
+QModelIndex UnityMenuModel::index(int row, int column, const QModelIndex &parent) const
+{
+    return createIndex(row, column);
+}
+
+QModelIndex UnityMenuModel::parent(const QModelIndex &index) const
+{
+    return QModelIndex();
+}
+
+QHash<int, QByteArray> UnityMenuModel::roleNames() const
+{
+    QHash<int, QByteArray> names;
+
+    names[LabelRole] = "label";
+    names[ActionRole] = "action";
+    names[SensitiveRole] = "sensitive";
+
+    return names;
+}
diff --git a/libqmenumodel/src/unitymenumodel.h b/libqmenumodel/src/unitymenumodel.h
new file mode 100644
index 0000000..12a5891
--- /dev/null
+++ b/libqmenumodel/src/unitymenumodel.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2013 Canonical Ltd.
+ *
+ * This program 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; version 3.
+ *
+ * This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Lars Uebernickel <lars.uebernickel@canonical.com>
+ */
+
+#ifndef UNITYMENUMODEL_H
+#define UNITYMENUMODEL_H
+
+#include <QAbstractListModel>
+
+class UnityMenuModel: public QAbstractListModel
+{
+    Q_OBJECT
+
+public:
+    enum MenuRoles {
+        ActionRole  = Qt::DisplayRole + 1,
+        LabelRole,
+        SensitiveRole
+    };
+
+public:
+    UnityMenuModel(const QByteArray &busName, const QByteArray &actionGroupObjectPath,
+                   const QByteArray &menuObjectPath, QObject *parent = NULL);
+    virtual ~UnityMenuModel();
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const;
+    int columnCount(const QModelIndex &parent = QModelIndex()) const;
+    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
+    QModelIndex index(int row, int column = 0, const QModelIndex &parent = QModelIndex()) const;
+    QModelIndex parent(const QModelIndex &index) const;
+    QHash<int, QByteArray> roleNames() const;
+
+protected:
+    UnityMenuModel(QObject *parent = NULL);
+    void init(const QByteArray &busName, const QByteArray &actionGroupObjectPath, const QByteArray &menuObjectPath);
+
+private:
+    class UnityMenuModelPrivate *priv;
+    friend class UnityMenuModelPrivate;
+};
+
+#endif
diff --git a/libqmenumodel/src/unityqmlmenumodel.cpp b/libqmenumodel/src/unityqmlmenumodel.cpp
new file mode 100644
index 0000000..775d974
--- /dev/null
+++ b/libqmenumodel/src/unityqmlmenumodel.cpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2013 Canonical Ltd.
+ *
+ * This program 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; version 3.
+ *
+ * This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Lars Uebernickel <lars.uebernickel@canonical.com>
+ */
+
+#include "unityqmlmenumodel.h"
+
+struct UnityQmlMenuModelPrivate
+{
+    QByteArray busName;
+    QByteArray actionObjectPath;
+    QByteArray menuObjectPath;
+};
+
+UnityQmlMenuModel::UnityQmlMenuModel(QObject *parent):
+    UnityMenuModel(parent)
+{
+    priv = new UnityQmlMenuModelPrivate;
+}
+
+UnityQmlMenuModel::~UnityQmlMenuModel()
+{
+    delete priv;
+}
+
+void UnityQmlMenuModel::classBegin()
+{
+}
+
+void UnityQmlMenuModel::componentComplete()
+{
+    if (priv->busName.isEmpty())
+        qWarning("UnityQmlMenuModel: property 'busName' must be set");
+    else if (priv->actionObjectPath.isEmpty())
+        qWarning("UnityQmlMenuModel: property 'actionObjectPath' must be set");
+    else if (priv->menuObjectPath.isEmpty())
+        qWarning("UnityQmlMenuModel: property 'menuObjectPath' must be set");
+    else
+        UnityQmlMenuModel::init(priv->busName, priv->actionObjectPath, priv->menuObjectPath);
+}
+
+QByteArray UnityQmlMenuModel::busName() const
+{
+    return priv->busName;
+}
+
+void UnityQmlMenuModel::setBusName(const QByteArray &name)
+{
+    if (!priv->busName.isEmpty()) {
+        qWarning("UnityQmlMenuModel: cannot change bus name after creation");
+        return;
+    }
+
+    priv->busName = name;
+    Q_EMIT busNameChanged(name);
+}
+
+QByteArray UnityQmlMenuModel::actionObjectPath() const
+{
+    return priv->actionObjectPath;
+}
+
+void UnityQmlMenuModel::setActionObjectPath(const QByteArray &path)
+{
+    if (!priv->actionObjectPath.isEmpty()) {
+        qWarning("UnityQmlMenuModel: cannot change object paths after creation");
+        return;
+    }
+
+    priv->actionObjectPath = path;
+    Q_EMIT actionObjectPathChanged(path);
+}
+
+QByteArray UnityQmlMenuModel::menuObjectPath() const
+{
+    return priv->menuObjectPath;
+}
+
+void UnityQmlMenuModel::setMenuObjectPath(const QByteArray &path)
+{
+    if (!priv->menuObjectPath.isEmpty()) {
+        qWarning("UnityQmlMenuModel: cannot change object paths after creation");
+        return;
+    }
+
+    priv->menuObjectPath = path;
+    Q_EMIT menuObjectPathChanged(path);
+}
+
diff --git a/libqmenumodel/src/unityqmlmenumodel.h b/libqmenumodel/src/unityqmlmenumodel.h
new file mode 100644
index 0000000..a375e8e
--- /dev/null
+++ b/libqmenumodel/src/unityqmlmenumodel.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2013 Canonical Ltd.
+ *
+ * This program 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; version 3.
+ *
+ * This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Lars Uebernickel <lars.uebernickel@canonical.com>
+ */
+
+#ifndef UNITYQMLENUMODEL_H
+#define UNITYQMLENUMODEL_H
+
+#include "unitymenumodel.h"
+
+#include <QQmlParserStatus>
+
+class UnityQmlMenuModel: public UnityMenuModel, public QQmlParserStatus
+{
+    Q_OBJECT
+    Q_INTERFACES(QQmlParserStatus)
+    Q_PROPERTY(QByteArray busName READ busName WRITE setBusName NOTIFY busNameChanged)
+    Q_PROPERTY(QByteArray actionObjectPath READ actionObjectPath WRITE setActionObjectPath NOTIFY actionObjectPathChanged)
+    Q_PROPERTY(QByteArray menuObjectPath READ menuObjectPath WRITE setMenuObjectPath NOTIFY menuObjectPathChanged)
+
+public:
+    UnityQmlMenuModel(QObject *parent = NULL);
+    ~UnityQmlMenuModel();
+
+    void classBegin();
+    void componentComplete();
+
+    QByteArray busName() const;
+    void setBusName(const QByteArray &name);
+
+    QByteArray actionObjectPath() const;
+    void setActionObjectPath(const QByteArray &path);
+
+    QByteArray menuObjectPath() const;
+    void setMenuObjectPath(const QByteArray &path);
+
+Q_SIGNALS:
+    void busNameChanged(const QByteArray &name);
+    void actionObjectPathChanged(const QByteArray &path);
+    void menuObjectPathChanged(const QByteArray &path);
+
+private:
+    struct UnityQmlMenuModelPrivate *priv;
+};
+
+#endif