[gtk+] widget: add helpers to resolve GActionGroups available to GtkWidget

[Christian Hergert <chergert src gnome org>]

commit 661da5558c14520070174b0fd65f1a9c508f4ca4
Author: Christian Hergert <christian hergert me>
Date:   Thu Dec 11 15:25:41 2014 -0800

    widget: add helpers to resolve GActionGroups available to GtkWidget
    
    These functions, while added for use by the GTK inspector, are generally
    useful to applications that need to resolve what action groups are
    available to a particular GtkWidget.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=741386

 docs/reference/gtk/gtk3-sections.txt |    2 +
 gtk/gtkactionmuxer.c                 |    4 +-
 gtk/gtkactionmuxer.h                 |    2 +-
 gtk/gtkwidget.c                      |   43 +++++++++++++++++++++++++++++----
 gtk/gtkwidget.h                      |    7 +++++
 gtk/gtkwidgetprivate.h               |    3 --
 gtk/inspector/actions.c              |    4 +-
 gtk/inspector/prop-editor.c          |    2 +-
 8 files changed, 52 insertions(+), 15 deletions(-)
---
diff --git a/docs/reference/gtk/gtk3-sections.txt b/docs/reference/gtk/gtk3-sections.txt
index fb93d29..857d0fb 100644
--- a/docs/reference/gtk/gtk3-sections.txt
+++ b/docs/reference/gtk/gtk3-sections.txt
@@ -5543,6 +5543,8 @@ gtk_widget_get_modifier_mask
 gtk_widget_insert_action_group
 gtk_widget_get_opacity
 gtk_widget_set_opacity
+gtk_widget_list_action_prefixes
+gtk_widget_get_action_group
 
 <SUBSECTION>
 gtk_widget_get_path
diff --git a/gtk/gtkactionmuxer.c b/gtk/gtkactionmuxer.c
index a1dc9f8..408973b 100644
--- a/gtk/gtkactionmuxer.c
+++ b/gtk/gtkactionmuxer.c
@@ -732,10 +732,10 @@ gtk_action_muxer_remove (GtkActionMuxer *muxer,
     }
 }
 
-gchar **
+const gchar **
 gtk_action_muxer_list_prefixes (GtkActionMuxer *muxer)
 {
-  return (gchar **) g_hash_table_get_keys_as_array (muxer->groups, NULL);
+  return (const gchar **) g_hash_table_get_keys_as_array (muxer->groups, NULL);
 }
 
 GActionGroup *
diff --git a/gtk/gtkactionmuxer.h b/gtk/gtkactionmuxer.h
index 94b7491..39e9bf2 100644
--- a/gtk/gtkactionmuxer.h
+++ b/gtk/gtkactionmuxer.h
@@ -41,7 +41,7 @@ void                    gtk_action_muxer_insert                         (GtkActi
 
 void                    gtk_action_muxer_remove                         (GtkActionMuxer *muxer,
                                                                          const gchar    *prefix);
-gchar **                gtk_action_muxer_list_prefixes                  (GtkActionMuxer *muxer);
+const gchar **          gtk_action_muxer_list_prefixes                  (GtkActionMuxer *muxer);
 GActionGroup *          gtk_action_muxer_lookup                         (GtkActionMuxer *muxer,
                                                                          const gchar    *prefix);
 GtkActionMuxer *        gtk_action_muxer_get_parent                     (GtkActionMuxer *muxer);
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 50ca98b..4d54206 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -17037,18 +17037,49 @@ gtk_widget_get_template_child (GtkWidget   *widget,
   return ret;
 }
 
-gchar **
-_gtk_widget_list_action_prefixes (GtkWidget *widget)
+/**
+ * gtk_widget_list_action_prefixes:
+ * @widget: A #GtkWidget
+ *
+ * Retrieves a %NULL-terminated array of strings containing the prefixes of
+ * #GActionGroup's available to @widget.
+ *
+ * Returns: (transfer container): a %NULL-terminated array of strings.
+ *
+ * Since: 3.16
+ */
+const gchar **
+gtk_widget_list_action_prefixes (GtkWidget *widget)
 {
+  g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
+
   if (widget->priv->muxer)
-    return gtk_action_muxer_list_prefixes (widget->priv->muxer);
-  return NULL;
+      return gtk_action_muxer_list_prefixes (widget->priv->muxer);
+  return g_new0 (const gchar *, 0 + 1);
 }
 
+/**
+ * gtk_widget_get_action_group:
+ * @widget: A #GtkWidget
+ * @prefix: The “prefix” of the action group.
+ *
+ * Retrieves the #GActionGroup that was registered using @prefix. The resulting
+ * #GActionGroup may have been registered to @widget or any #GtkWidget in its
+ * ancestry.
+ *
+ * If no action group was found matching @prefix, then %NULL is returned.
+ *
+ * Returns: (transfer none) (nullable): A #GActionGroup or %NULL.
+ *
+ * Since: 3.16
+ */
 GActionGroup *
-_gtk_widget_get_action_group (GtkWidget   *widget,
-                              const gchar *prefix)
+gtk_widget_get_action_group (GtkWidget   *widget,
+                             const gchar *prefix)
 {
+  g_return_val_if_fail (GTK_IS_WIDGET (widget), NULL);
+  g_return_val_if_fail (prefix, NULL);
+
   if (widget->priv->muxer)
     return gtk_action_muxer_lookup (widget->priv->muxer, prefix);
   return NULL;
diff --git a/gtk/gtkwidget.h b/gtk/gtkwidget.h
index ca961a0..450cd19 100644
--- a/gtk/gtkwidget.h
+++ b/gtk/gtkwidget.h
@@ -1475,6 +1475,13 @@ void    gtk_widget_class_bind_template_child_full       (GtkWidgetClass        *
                                                         gboolean               internal_child,
                                                         gssize                 struct_offset);
 
+GDK_AVAILABLE_IN_3_16
+GActionGroup           *gtk_widget_get_action_group                     (GtkWidget    *widget,
+                                                                         const gchar  *prefix);
+
+GDK_AVAILABLE_IN_3_16
+const gchar **          gtk_widget_list_action_prefixes                 (GtkWidget    *widget);
+
 G_END_DECLS
 
 #endif /* __GTK_WIDGET_H__ */
diff --git a/gtk/gtkwidgetprivate.h b/gtk/gtkwidgetprivate.h
index 6fd7a63..48c9f8c 100644
--- a/gtk/gtkwidgetprivate.h
+++ b/gtk/gtkwidgetprivate.h
@@ -153,9 +153,6 @@ void              _gtk_widget_style_context_invalidated    (GtkWidget    *widget
 void              _gtk_widget_update_parent_muxer          (GtkWidget    *widget);
 GtkActionMuxer *  _gtk_widget_get_action_muxer             (GtkWidget    *widget,
                                                             gboolean      create);
-gchar **          _gtk_widget_list_action_prefixes         (GtkWidget    *widget);
-GActionGroup *    _gtk_widget_get_action_group             (GtkWidget    *widget,
-                                                            const gchar  *prefix);
 
 void              _gtk_widget_add_controller               (GtkWidget           *widget,
                                                             GtkEventController  *controller);
diff --git a/gtk/inspector/actions.c b/gtk/inspector/actions.c
index 7899bcf..ff8e2e1 100644
--- a/gtk/inspector/actions.c
+++ b/gtk/inspector/actions.c
@@ -220,12 +220,12 @@ gtk_inspector_actions_set_object (GtkInspectorActions *sl,
       GActionGroup *group;
       gint i;
 
-      prefixes = _gtk_widget_list_action_prefixes (GTK_WIDGET (object));
+      prefixes = gtk_widget_list_action_prefixes (GTK_WIDGET (object));
       if (prefixes)
         {
           for (i = 0; prefixes[i]; i++)
             {
-              group = _gtk_widget_get_action_group (GTK_WIDGET (object), prefixes[i]);
+              group = gtk_widget_get_action_group (GTK_WIDGET (object), prefixes[i]);
               add_group (sl, group, prefixes[i]);
             }
           g_free (prefixes);
diff --git a/gtk/inspector/prop-editor.c b/gtk/inspector/prop-editor.c
index 3649e78..8a28539 100644
--- a/gtk/inspector/prop-editor.c
+++ b/gtk/inspector/prop-editor.c
@@ -1262,7 +1262,7 @@ find_action_owner (GtkActionable *actionable)
 
   while (widget != NULL)
     {
-      group = _gtk_widget_get_action_group (widget, prefix);
+      group = gtk_widget_get_action_group (widget, prefix);
       if (group && g_action_group_has_action (group, name))
         return (GObject *)widget;
       widget = action_ancestor (widget);