[gtk+] add gtk_radio_button_join_group method for bindings

[John Palmieri <johnp src gnome org>]

commit 8a210673fb6f05abaa4ea05b7dcd17b06c7aca68
Author: John (J5) Palmieri <johnp redhat com>
Date:   Mon Sep 6 22:55:03 2010 -0400

    add gtk_radio_button_join_group method for bindings
    
    * this mirrors the committed change for gtk_radio_action_join_group in
      commit 85b53969b24d318b219663841e678943516f443a
    * Due to object ownership issues it is impossible to correctly use
      get_group/set_group from a GI binding
    * join_group is safer because at the binding level it works with individual
      GtkRadioButton objects and not with the list of objects that gets
      modified in the library
    
    https://bugzilla.gnome.org/show_bug.cgi?id=628935

 gtk/gtkradiobutton.c |   55 ++++++++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtkradiobutton.h |    3 +-
 2 files changed, 57 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkradiobutton.c b/gtk/gtkradiobutton.c
index fc78ead..6881e10 100644
--- a/gtk/gtkradiobutton.c
+++ b/gtk/gtkradiobutton.c
@@ -347,6 +347,61 @@ gtk_radio_button_set_group (GtkRadioButton *radio_button,
 }
 
 /**
+ * gtk_radio_button_join_group:
+ * @radio_button: the #GtkRadioButton object
+ * @group_source: (allow-none): a radio button object whos group we are 
+ *   joining, or %NULL to remove the radio button from its group
+ *
+ * Joins a #GtkRadioButton object to the group of another #GtkRadioButton object
+ *
+ * Use this in language bindings instead of the gtk_radio_button_get_group() 
+ * and gtk_radio_button_set_group() methods
+ *
+ * A common way to set up a group of radio buttons is the following:
+ * |[
+ *   GtkRadioButton *radio_button;
+ *   GtkRadioButton *last_button;
+ *
+ *   while (/&ast; more buttons to add &ast;/)
+ *     {
+ *        radio_button = gtk_radio_button_new (...);
+ *
+ *        gtk_radio_button_join_group (radio_button, last_button);
+ *        last_button = radio_button;
+ *     }
+ * ]|
+ *
+ * Since: 3.0
+ */
+void
+gtk_radio_button_join_group (GtkRadioButton *radio_button, 
+			     GtkRadioButton *group_source)
+{
+  g_return_if_fail (GTK_IS_RADIO_BUTTON (radio_button));
+  g_return_if_fail (group_source == NULL || GTK_IS_RADIO_BUTTON (group_source));
+
+  if (group_source)
+    {
+      GSList *group;
+      group = gtk_radio_button_get_group (group_source);
+
+      if (!group)
+        {
+          /* if we are not already part of a group we need to set up a new one
+             and then get the newly created group */
+          gtk_radio_button_set_group (group_source, NULL);
+          group = gtk_radio_button_get_group (group_source);
+        }
+
+      gtk_radio_button_set_group (radio_button, group);
+    }
+  else
+    {
+      gtk_radio_button_set_group (radio_button, NULL);
+    }
+}
+
+/**
  * gtk_radio_button_new:
  * @group: an existing radio button group, or %NULL if you are creating a new group.
  *
diff --git a/gtk/gtkradiobutton.h b/gtk/gtkradiobutton.h
index 84e7042..20f91cf 100644
--- a/gtk/gtkradiobutton.h
+++ b/gtk/gtkradiobutton.h
@@ -86,7 +86,8 @@ GtkWidget* gtk_radio_button_new_with_mnemonic_from_widget (GtkRadioButton *radio
 GSList*    gtk_radio_button_get_group                     (GtkRadioButton *radio_button);
 void       gtk_radio_button_set_group                     (GtkRadioButton *radio_button,
                                                            GSList         *group);
-
+void            gtk_radio_button_join_group        (GtkRadioButton        *radio_button,
+                                                    GtkRadioButton        *group_source);
 G_END_DECLS
 
 #endif /* __GTK_RADIO_BUTTON_H__ */