Menus and refcounting

[Owen Taylor <otaylor redhat com>]

I just noticed that my recent menu changes resulted
in refcounting for menus being a bit screwy.

The way it used to be:

 Menus were created floating with a refcount of 1. If/when
 a menu was attached to something with gtk_menu_attach_to_widget.
 (E.g., this is called by gtk_menu_item_set_submenu), they
 were sunk. By convention when the attach_widget was destroyed,
 it destroyed the men. If the menu was detached, it was  
 unref'ed.

The way it is now.

 Menus, when created immediately add themselves at once to a parent
 that they create. (Menus are no longer toplevel
 widgets) This means that they get a non-floating refcount
 of 1. When a menu is attached to something, the refcount
 is incremented to 2. If the attach_widget is destroyed,
 then it destroys the menu, the toplevel is destroyed,
 both refcounts are released, and everything is fine. If
 the menu is removed from the attach_widget, the refcount
 will remain at 1, and the menu potentially leaks.

I think the "right" thing to do here is to try and restore
the old behavior, since that is pretty much constistant
with how other widgets work.

So, what I plan to do now are hacks like:

  gboolean was_floating = GTK_WIDGET_FLOATING (menu);
  gtk_container_add (GTK_CONTAINER (menu->toplevel), GTK_WIDGET (menu));
  if (was_floating)
    GTK_WIDGET_SET_FLAGS (GTK_WIDGET (menu), FLOATING);
  gtk_widget_unref (menu);

[...]

  gtk_widget_ref (menu);
  gtk_container_remove (GTK_CONTAINER (menu->toplevel), widget);

That is hiding the toplevel=>menu refcount, but recreating
it when needed. This is ugly, but shouldn't be apparent
to users. I'd appreciate better ideas, however.

Regards,
                                        Owen