[PATCH v2] refs: use skip_prefix() in ref_is_hidden()

[PATCH v2] refs: use skip_prefix() in ref_is_hidden()

[Christian Couder]

This is shorter, makes the logic a bit easier to follow, and is
perhaps a bit faster too.

The logic is to make the final decision only when "subject" is there,
its early part matches "match", and the match is at the slash
boundary (or the whole thing).

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---

The change with the previous version was suggested by Junio in

https://public-inbox.org/git/xmqqk231hgpz.fsf@gitster.mtv.corp.google.com/

 refs.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/refs.c b/refs.c
index ba22f4acef..ea2b9f84f8 100644
--- a/refs.c
+++ b/refs.c
@@ -1160,7 +1160,7 @@ int ref_is_hidden(const char *refname, const char *refname_full)
 		const char *match = hide_refs->items[i].string;
 		const char *subject;
 		int neg = 0;
-		int len;
+		const char *p;
 
 		if (*match == '!') {
 			neg = 1;
@@ -1175,10 +1175,9 @@ int ref_is_hidden(const char *refname, const char *refname_full)
 		}
 
 		/* refname can be NULL when namespaces are used. */
-		if (!subject || !starts_with(subject, match))
-			continue;
-		len = strlen(match);
-		if (!subject[len] || subject[len] == '/')
+		if (subject &&
+		    skip_prefix(subject, match, &p) &&
+		    (!*p || *p == '/'))
 			return !neg;
 	}
 	return 0;
-- 
2.14.0.rc0.26.g981adb928e.dirty

Re: [PATCH v2] refs: use skip_prefix() in ref_is_hidden()

[Jeff King]

On Sat, Jul 22, 2017 at 06:39:12AM +0200, Christian Couder wrote:

> @@ -1175,10 +1175,9 @@ int ref_is_hidden(const char *refname, const char *refname_full)
>  		}
>  
>  		/* refname can be NULL when namespaces are used. */
> -		if (!subject || !starts_with(subject, match))
> -			continue;
> -		len = strlen(match);
> -		if (!subject[len] || subject[len] == '/')
> +		if (subject &&
> +		    skip_prefix(subject, match, &p) &&
> +		    (!*p || *p == '/'))
>  			return !neg;

This looks good to me.

I seem to recall running across a similar pattern elsewhere, where a
caller wanted either an exact match, or a match ending with a particular
character. We could add one more helper like:

  if (subject && skip_prefix_with_sep(subject, match, '/', &p))
	return !neg;

But I don't offhand recall where that other place was, and it's not like
it's saving a huge amount of complexity in the caller. So I'll file it
away in the back of my mind and see if it comes up a third time. ;)

-Peff