shared: add nm_c_list_for_each_entry_prev() helper macro

It's non-trivial to get this right. Add the macro for iterating the list
in reverse.

1 files changed, 6 insertions, 0 deletions

diff --git a/shared/nm-glib-aux/nm-c-list.h b/shared/nm-glib-aux/nm-c-list.h
index 7a6e8ccaf2..256dda74fb 100644
--- a/shared/nm-glib-aux/nm-c-list.h
+++ b/shared/nm-glib-aux/nm-c-list.h
@@ -17,6 +17,12 @@
 		_what && c_list_contains (list, &_what->member); \
 	})
 
+/* iterate over the list backwards. */
+#define nm_c_list_for_each_entry_prev(_iter, _list, _m) \
+	for (_iter = c_list_entry ((_list)->prev, __typeof__ (*_iter), _m); \
+	     &(_iter)->_m != (_list); \
+	     _iter = c_list_entry ((_iter)->_m.prev, __typeof__ (*_iter), _m))
+
 /*****************************************************************************/
 
 typedef struct {