int quiet);
struct commit *lookup_commit_reference_by_name(const char *name);
+/*
+ * Look up object named by "sha1", dereference tag as necessary,
+ * get a commit and return it. If "sha1" does not dereference to
+ * a commit, use ref_name to report an error and die.
+ */
+struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name);
+
int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size);
int parse_commit(struct commit *item);