diff --git a/model/sync-leaf.h b/model/sync-leaf.h
index a4c64cf..c4da60c 100644
--- a/model/sync-leaf.h
+++ b/model/sync-leaf.h
@@ -70,6 +70,7 @@
 };
 
 typedef boost::shared_ptr<Leaf> LeafPtr;
+typedef boost::shared_ptr<const Leaf> LeafConstPtr;
 
 } // Sync