Clean-up lock-ref implementation

This drops "mustexist" parameter lock_ref_sha1() and lock_any_ref_forupdate()
functions take.

Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-pack-refs.c

@@ -53,7 +53,7 @@ static int handle_one_ref(const char *path, const unsigned char *sha1,
 /* make sure nobody touched the ref, and unlink */
 static void prune_ref(struct ref_to_prune *r)
 {
-	struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1, 1);
+	struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
 
 	if (lock) {
 		unlink(git_path("%s", r->name));

builtin-update-ref.c

@@ -48,7 +48,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 	if (oldval && get_sha1(oldval, oldsha1))
 		die("%s: not a valid old SHA1", oldval);
 
-	lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL, 0);
+	lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL);
 	if (!lock)
 		return 1;
 	if (write_ref_sha1(lock, sha1, msg) < 0)

fetch.c

@@ -266,7 +266,7 @@ int pull(int targets, char **target, const char **write_ref,
 		if (!write_ref || !write_ref[i])
 			continue;
 
-		lock[i] = lock_ref_sha1(write_ref[i], NULL, 0);
+		lock[i] = lock_ref_sha1(write_ref[i], NULL);
 		if (!lock[i]) {
 			error("Can't lock ref %s", write_ref[i]);
 			goto unlock_and_fail;

refs.c

@@ -447,12 +447,13 @@ static struct ref_lock *verify_lock(struct ref_lock *lock,
 	return lock;
 }
 
-static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int mustexist)
+static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1)
 {
 	char *ref_file;
 	const char *orig_ref = ref;
 	struct ref_lock *lock;
 	struct stat st;
+	int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
 
 	lock = xcalloc(1, sizeof(struct ref_lock));
 	lock->lock_fd = -1;
@@ -480,20 +481,18 @@ static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char
 	return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 }
 
-struct ref_lock *lock_ref_sha1(const char *ref,
-	const unsigned char *old_sha1, int mustexist)
+struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 {
 	char refpath[PATH_MAX];
 	if (check_ref_format(ref))
 		return NULL;
 	strcpy(refpath, mkpath("refs/%s", ref));
-	return lock_ref_sha1_basic(refpath, old_sha1, mustexist);
+	return lock_ref_sha1_basic(refpath, old_sha1);
 }
 
-struct ref_lock *lock_any_ref_for_update(const char *ref,
-	const unsigned char *old_sha1, int mustexist)
+struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
 {
-	return lock_ref_sha1_basic(ref, old_sha1, mustexist);
+	return lock_ref_sha1_basic(ref, old_sha1);
 }
 
 void unlock_ref(struct ref_lock *lock)

refs.h

@@ -27,10 +27,10 @@ extern int for_each_remote_ref(each_ref_fn, void *);
 extern int get_ref_sha1(const char *ref, unsigned char *sha1);
 
 /** Locks a "refs/" ref returning the lock on success and NULL on failure. **/
-extern struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1, int mustexist);
+extern struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1);
 
 /** Locks any ref (for 'HEAD' type refs). */
-extern struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int mustexist);
+extern struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1);
 
 /** Release any lock taken but not written. **/
 extern void unlock_ref(struct ref_lock *lock);