Re: [PATCH v2 00/21] object_id part 7

[Jeff King <peff@peff.net>]

On Tue, Mar 28, 2017 at 01:35:36PM -0400, Jeff King wrote:

> I thought I'd knock this out quickly before I forgot about it. But it
> actually isn't so simple.
> 
> The main caller in read_head_info() does indeed just pass strlen(line)
> as the length in each case. But the cert parser really does need us to
> respect the line length. So we either have to pass it in, or tie off the
> string.
> 
> The latter looks something like the patch below (on top of a minor
> tweak around "eol" handling). It's sufficiently ugly that it may not
> count as an actual cleanup, though. I'm OK if we just drop the idea.

Here's that minor tweak, in case anybody is interested. It's less useful
without that follow-on that touches "eol" more, but perhaps it increases
readability on its own.

-- >8 --
Subject: [PATCH] receive-pack: simplify eol handling in cert parsing

The queue_commands_from_cert() function wants to handle each
line of the cert individually. It looks for "\n" in the
to-be-parsed bytes, and special-cases each use of eol (the
end-of-line variable) when we didn't find one.  Instead, we
can just set the end-of-line variable to end-of-cert in the
latter case.

For advancing to the next line, it's OK for us to move our
pointer past end-of-cert, because our loop condition just
checks for pointer inequality. And it doesn't even violate
the ANSI C "no more than one past the end of an array" rule,
because we know in the worst case we've hit the terminating
NUL of the strbuf.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/receive-pack.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 5d9e4da0a..58de2a1a9 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1524,8 +1524,10 @@ static void queue_commands_from_cert(struct command **tail,
 
 	while (boc < eoc) {
 		const char *eol = memchr(boc, '\n', eoc - boc);
-		tail = queue_command(tail, boc, eol ? eol - boc : eoc - boc);
-		boc = eol ? eol + 1 : eoc;
+		if (!eol)
+			eol = eoc;
+		tail = queue_command(tail, boc, eol - boc);
+		boc = eol + 1;
 	}
 }
 
-- 
2.12.2.845.g55fcf8b10