[PATCH] Operations on refs

This patch adds code to read a hash out of a specified file under
{GIT_DIR}/refs/, and to write such files atomically and optionally with an
compare and lock.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/refs.h b/refs.h
new file mode 100644
index 000000000..60cf48086
--- /dev/null
+++ b/refs.h
@@ -0,0 +1,21 @@
+#ifndef REFS_H
+#define REFS_H
+
+/** Reads the refs file specified into sha1 **/
+extern int get_ref_sha1(const char *ref, unsigned char *sha1);
+
+/** Locks ref and returns the fd to give to write_ref_sha1() if the ref
+ * has the given value currently; otherwise, returns -1.
+ **/
+extern int lock_ref_sha1(const char *ref, const unsigned char *old_sha1);
+
+/** Writes sha1 into the refs file specified, locked with the given fd. **/
+extern int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1);
+
+/** Writes sha1 into the refs file specified. **/
+extern int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1);
+
+/** Returns 0 if target has the right format for a ref. **/
+extern int check_ref_format(const char *target);
+
+#endif /* REFS_H */