diff --git a/commit.h b/commit.h
index fc13de9..c559510 100644
--- a/commit.h
+++ b/commit.h
@@ -97,7 +97,7 @@
 
 struct commit_graft {
 	unsigned char sha1[20];
-	int nr_parent;
+	int nr_parent; /* < 0 if shallow commit */
 	unsigned char parent[FLEX_ARRAY][20]; /* more */
 };
 
@@ -107,4 +107,10 @@
 
 extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
 
+extern int register_shallow(const unsigned char *sha1);
+extern int write_shallow_commits(int fd, int use_pack_protocol);
+extern int is_repository_shallow();
+extern struct commit_list *get_shallow_commits(struct object_array *heads,
+		int depth);
+
 #endif /* COMMIT_H */