[libwnck/wip/muktupavels/issue-141] class-group: add a weak reference callback to window

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 1d512e7fd5487e5381489814e00adbeed2cdc5f9
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Fri Aug 2 20:43:50 2019 +0300

    class-group: add a weak reference callback to window
    
    When wnck_shutdown is called all windows are destroyed, but nothing
    removes signal handlers from hash tables. When class group is destoryed
    it will try to remove signal handlers from already destoryed windows.
    
    Use weak reference callback to remove obsolete signal handlers from
    hash tables.
    
    https://gitlab.gnome.org/GNOME/libwnck/merge_requests/11

 libwnck/class-group.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
---
diff --git a/libwnck/class-group.c b/libwnck/class-group.c
index 2a274e2..e90a466 100644
--- a/libwnck/class-group.c
+++ b/libwnck/class-group.c
@@ -496,6 +496,20 @@ update_class_group_name (WnckWindow     *window,
   set_name (class_group);
 }
 
+static void
+window_weak_notify_cb (gpointer  data,
+                       GObject  *where_the_object_was)
+{
+  WnckClassGroup *class_group;
+  WnckClassGroupPrivate *priv;
+
+  class_group = WNCK_CLASS_GROUP (data);
+  priv = class_group->priv;
+
+  g_hash_table_remove (priv->window_icon_handlers, where_the_object_was);
+  g_hash_table_remove (priv->window_name_handlers, where_the_object_was);
+}
+
 /**
  * _wnck_class_group_add_window:
  * @class_group: a #WnckClassGroup.
@@ -534,6 +548,8 @@ _wnck_class_group_add_window (WnckClassGroup *class_group,
                        window,
                        (gpointer) signal_id);
 
+  g_object_weak_ref (G_OBJECT (window), window_weak_notify_cb, class_group);
+
   set_name (class_group);
   set_icon (class_group);