[gimp] Add more precondition checks to gimp_item_tree_get_insert_pos()

[Michael Natterer <mitch src gnome org>]

commit e83954c49a95721eac9dd9b6ada7b98024986e4d
Author: Michael Natterer <mitch gimp org>
Date:   Tue Feb 9 00:33:41 2010 +0100

    Add more precondition checks to gimp_item_tree_get_insert_pos()

 app/core/gimpitemtree.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)
---
diff --git a/app/core/gimpitemtree.c b/app/core/gimpitemtree.c
index 388a098..9623516 100644
--- a/app/core/gimpitemtree.c
+++ b/app/core/gimpitemtree.c
@@ -337,6 +337,23 @@ gimp_item_tree_get_insert_pos (GimpItemTree *tree,
 
   private = GIMP_ITEM_TREE_GET_PRIVATE (tree);
 
+  g_return_val_if_fail (parent == NULL ||
+                        parent == GIMP_IMAGE_ACTIVE_PARENT ||
+                        G_TYPE_CHECK_INSTANCE_TYPE (parent, private->item_type),
+                        FALSE);
+  g_return_val_if_fail (parent == NULL ||
+                        parent == GIMP_IMAGE_ACTIVE_PARENT ||
+                        gimp_item_is_attached (parent), FALSE);
+  g_return_val_if_fail (parent == NULL ||
+                        parent == GIMP_IMAGE_ACTIVE_PARENT ||
+                        gimp_item_get_image (parent) == private->image,
+                        FALSE);
+  g_return_val_if_fail (parent == NULL ||
+                        parent == GIMP_IMAGE_ACTIVE_PARENT ||
+                        gimp_viewable_get_children (GIMP_VIEWABLE (parent)),
+                        FALSE);
+  g_return_val_if_fail (position != NULL, NULL);
+
   /*  if we want to insert in the active item's parent container  */
   if (parent == GIMP_IMAGE_ACTIVE_PARENT)
     {