[PATCH 2/3] validate_headref: use skip_prefix for symref parsing

From: Jeff King <peff@peff.net>
Date: Sep 27, 2017, 06:17 UTC
Message-ID: <20170927061726.gat3ykqx4fdstzq6@sigill.intra.peff.net>
In-Reply-To: <20170927061644.gwlhxaiairiy2njp@sigill.intra.peff.net>

Since the previous commit guarantees that our symref buffer is NUL-terminated, we can just use skip_prefix() and friends to parse it. This is shorter and saves us having to deal with magic numbers and keeping the "len" counter up to date.

While we're at it, let's name the rather obscure "buf" to "refname", since that is the thing we are parsing with it.

Signed-off-by: Jeff King <peff@peff.net>
---
 path.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/path.c b/path.c
index 3e4d7505ef..2ef3a86613 100644
--- a/path.c
+++ b/path.c
@@ -637,7 +637,8 @@ void strbuf_git_common_path(struct strbuf *sb,
 int validate_headref(const char *path)
 {
 	struct stat st;
-	char *buf, buffer[256];
+	char buffer[256];
+	const char *refname;
 	unsigned char sha1[20];
 	int fd;
 	ssize_t len;
@@ -669,14 +670,10 @@ int validate_headref(const char *path)
 	/*
 	 * Is it a symbolic ref?
 	 */
-	if (len < 4)
-		return -1;
-	if (!memcmp("ref:", buffer, 4)) {
-		buf = buffer + 4;
-		len -= 4;
-		while (len && isspace(*buf))
-			buf++, len--;
-		if (len >= 5 && !memcmp("refs/", buf, 5))
+	if (skip_prefix(buffer, "ref:", &refname)) {
+		while (isspace(*refname))
+			refname++;
+		if (starts_with(refname, "refs/"))
 			return 0;
 	}

-- 
2.14.2.988.g01c8b37dde