diff --git a/model/sync-diff-leaf.cc b/model/sync-diff-leaf.cc
index 2680859..59e0fc1 100644
--- a/model/sync-diff-leaf.cc
+++ b/model/sync-diff-leaf.cc
@@ -19,3 +19,21 @@
  *         卞超轶 Chaoyi Bian <bcy@pku.edu.cn>
  *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
  */
+
+#include "sync-diff-leaf.h"
+
+namespace Sync {
+
+DiffLeaf::DiffLeaf (NameInfoConstPtr info, const SeqNo &seq)
+  : Leaf (info, seq)
+  , m_op (UPDATE)
+{
+}
+
+DiffLeaf::DiffLeaf (NameInfoConstPtr info)
+  : Leaf (info, SeqNo (0,0))
+  , m_op (REMOVE)
+{
+}
+
+}