commit_lock_file(): use get_locked_file_path()

First beef up the sanity checking in get_locked_file_path() to match
that in commit_lock_file(). Then rewrite commit_lock_file() to use
get_locked_file_path() for its pathname computation.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

lockfile.c

@@ -389,8 +389,10 @@ char *get_locked_file_path(struct lock_file *lk)
 {
 	if (!lk->active)
 		die("BUG: get_locked_file_path() called for unlocked object");
-	if (lk->filename.len <= LOCK_SUFFIX_LEN)
+	if (lk->filename.len <= LOCK_SUFFIX_LEN ||
+	    strcmp(lk->filename.buf + lk->filename.len - LOCK_SUFFIX_LEN, LOCK_SUFFIX))
 		die("BUG: get_locked_file_path() called for malformed lock object");
+	/* remove ".lock": */
 	return xmemdupz(lk->filename.buf, lk->filename.len - LOCK_SUFFIX_LEN);
 }
 
@@ -458,22 +460,16 @@ int commit_lock_file_to(struct lock_file *lk, const char *path)
 
 int commit_lock_file(struct lock_file *lk)
 {
-	static struct strbuf result_file = STRBUF_INIT;
-	int err;
+	char *result_path = get_locked_file_path(lk);
 
-	if (!lk->active)
-		die("BUG: attempt to commit unlocked object");
-
-	if (lk->filename.len <= LOCK_SUFFIX_LEN ||
-	    strcmp(lk->filename.buf + lk->filename.len - LOCK_SUFFIX_LEN, LOCK_SUFFIX))
-		die("BUG: lockfile filename corrupt");
-
-	/* remove ".lock": */
-	strbuf_add(&result_file, lk->filename.buf,
-		   lk->filename.len - LOCK_SUFFIX_LEN);
-	err = commit_lock_file_to(lk, result_file.buf);
-	strbuf_reset(&result_file);
-	return err;
+	if (commit_lock_file_to(lk, result_path)) {
+		int save_errno = errno;
+		free(result_path);
+		errno = save_errno;
+		return -1;
+	}
+	free(result_path);
+	return 0;
 }
 
 void rollback_lock_file(struct lock_file *lk)