Find tooltip/dnd widget running through container children in inverse order

Usually, educated GtkContainers' forall() implementation returns children
in an order that's safe for the default draw() implementation in GtkContainer.
So for widgets with some stacking notions (eg. GtkOverlay),
_gtk_widget_find_at_coords() needs to recurse within containers in reverse
order so it finds the topmost widget.

As this function is used in both tooltips and DnD code, this improves behavior
of "floating" widgets wrt those two. This could for example be seen in the
"Transparent" GTK+ demo, where dropping text on the entry results on the text
going to the textview.

https://bugzilla.gnome.org/show_bug.cgi?id=699239

1 files changed, 19 insertions, 1 deletions

diff --git a/gtk/gtktooltip.c b/gtk/gtktooltip.c
index aba9ffb38a..0914641c5d 100644
--- a/gtk/gtktooltip.c
+++ b/gtk/gtktooltip.c
@@ -692,6 +692,15 @@ struct ChildLocation
 };
 
 static void
+prepend_and_ref_widget (GtkWidget *widget,
+                        gpointer   data)
+{
+  GSList **slist_p = data;
+
+  *slist_p = g_slist_prepend (*slist_p, g_object_ref (widget));
+}
+
+static void
 child_location_foreach (GtkWidget *child,
 			gpointer   data)
 {
@@ -735,6 +744,7 @@ child_location_foreach (GtkWidget *child,
 	  if (GTK_IS_CONTAINER (child))
 	    {
 	      struct ChildLocation tmp = { NULL, NULL, 0, 0 };
+              GSList *children = NULL, *tmp_list;
 
 	      /* Take (x, y) relative the child's allocation and
 	       * recurse.
@@ -744,12 +754,20 @@ child_location_foreach (GtkWidget *child,
 	      tmp.container = child;
 
 	      gtk_container_forall (GTK_CONTAINER (child),
-				    child_location_foreach, &tmp);
+				    prepend_and_ref_widget, &children);
+
+              for (tmp_list = children; tmp_list; tmp_list = tmp_list->next)
+                {
+                  child_location_foreach (tmp_list->data, &tmp);
+                  g_object_unref (tmp_list->data);
+                }
 
 	      if (tmp.child)
 		child_loc->child = tmp.child;
 	      else
 		child_loc->child = child;
+
+              g_slist_free (children);
 	    }
 	  else
 	    child_loc->child = child;