[gdm/gnome-2-30] Use a cheaper way to find the active item in the list

[William Jon McCann <mccann src gnome org>]

commit e850a8bc5e0149b7f669fa29a41d0022cd312ec6
Author: William Jon McCann <jmccann redhat com>
Date:   Wed Jun 9 18:04:42 2010 -0400

    Use a cheaper way to find the active item in the list
    
    https://bugzilla.gnome.org/show_bug.cgi?id=621131

 gui/simple-greeter/gdm-chooser-widget.c |   43 ++++++++++++++++--------------
 1 files changed, 23 insertions(+), 20 deletions(-)
---
diff --git a/gui/simple-greeter/gdm-chooser-widget.c b/gui/simple-greeter/gdm-chooser-widget.c
index f69f058..53b5074 100644
--- a/gui/simple-greeter/gdm-chooser-widget.c
+++ b/gui/simple-greeter/gdm-chooser-widget.c
@@ -678,6 +678,21 @@ update_chooser_visibility (GdmChooserWidget *widget)
         return FALSE;
 }
 
+static inline gboolean
+iters_equal (GtkTreeIter *a,
+             GtkTreeIter *b)
+{
+        if (a->stamp != b->stamp)
+                return FALSE;
+
+        if (a->user_data != b->user_data)
+                return FALSE;
+
+        /* user_data2 and user_data3 are not used in GtkListStore */
+
+        return TRUE;
+}
+
 static void
 set_inactive_items_visible (GdmChooserWidget *widget,
                             gboolean          should_show)
@@ -687,38 +702,26 @@ set_inactive_items_visible (GdmChooserWidget *widget,
         GtkTreeIter   active_item_iter;
         GtkTreeIter   iter;
 
+        active_item_id = get_active_item_id (widget, &active_item_iter);
+        if (active_item_id == NULL) {
+                g_debug ("No active item set");
+        }
+
         model = GTK_TREE_MODEL (widget->priv->list_store);
 
         if (!gtk_tree_model_get_iter_first (model, &iter)) {
                 return;
         }
 
-        active_item_id = get_active_item_id (widget, &active_item_iter);
-
         do {
-                gboolean is_active;
-
-                is_active = FALSE;
-                if (active_item_id != NULL) {
-                        char *id;
-
-                        gtk_tree_model_get (model, &iter,
-                                            CHOOSER_ID_COLUMN, &id, -1);
-
-                        if (strcmp (active_item_id, id) == 0) {
-                                is_active = TRUE;
-                                g_free (active_item_id);
-                                active_item_id = NULL;
-                        }
-                        g_free (id);
-                }
-
-                if (!is_active) {
+                if (active_item_id == NULL || !iters_equal (&active_item_iter, &iter)) {
+                        /* inactive item */
                         gtk_list_store_set (widget->priv->list_store,
                                             &iter,
                                             CHOOSER_ITEM_IS_VISIBLE_COLUMN, should_show,
                                             -1);
                 } else {
+                        /* always show the active item */
                         gtk_list_store_set (widget->priv->list_store,
                                             &iter,
                                             CHOOSER_ITEM_IS_VISIBLE_COLUMN, TRUE,