use skip_prefix to avoid repeated calculations

In some cases, we use starts_with to check for a prefix, and
then use an already-calculated prefix length to advance a
pointer past the prefix. There are no magic numbers or
duplicated strings here, but we can still make the code
simpler and more obvious by using skip_prefix.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/http.c b/http.c
index 2b4f6a357c..f04621e61d 100644
--- a/http.c
+++ b/http.c
@@ -1087,11 +1087,10 @@ static int update_url_from_redirect(struct strbuf *base,
 	if (!strcmp(asked, got->buf))
 		return 0;
 
-	if (!starts_with(asked, base->buf))
+	if (!skip_prefix(asked, base->buf, &tail))
 		die("BUG: update_url_from_redirect: %s is not a superset of %s",
 		    asked, base->buf);
 
-	tail = asked + base->len;
 	tail_len = strlen(tail);
 
 	if (got->len < tail_len ||