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From: Jeff King <peff@peff.net>
To: Eric Sunshine <sunshine@sunshineco.com>
Cc: Carlo Arenas <carenas@gmail.com>, Git List <git@vger.kernel.org>,
	Hamza Mahfooz <someguy@effective-light.com>
Subject: Re: [PATCH 1/5] grep: stop modifying buffer in strip_timestamp
Date: Tue, 21 Sep 2021 01:43:05 -0400	[thread overview]
Message-ID: <YUlw6V7AL8l6mbSh@coredump.intra.peff.net> (raw)
In-Reply-To: <CAPig+cQnC1LLPtuC0qVX7EQ_ki4pev6scRox3utA45XeLHfGig@mail.gmail.com>

On Tue, Sep 21, 2021 at 01:24:41AM -0400, Eric Sunshine wrote:

> On Tue, Sep 21, 2021 at 1:18 AM Carlo Arenas <carenas@gmail.com> wrote:
> > On Mon, Sep 20, 2021 at 9:09 PM Jeff King <peff@peff.net> wrote:
> > > @@ -971,7 +966,7 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
> > >                 switch (p->field) {
> > >                 case GREP_HEADER_AUTHOR:
> > >                 case GREP_HEADER_COMMITTER:
> > > -                       saved_ch = strip_timestamp(bol, &eol);
> > > +                       strip_timestamp(bol, &eol);
> >
> > Why not something like (plus added error handling, even if it seems
> > the original didn't have them)?
> >
> >   eol = strrchr(bol, '>');
> 
> strrchr() would search backward from the NUL, not from `eol`, thus
> would not be a faithful conversion (and might not be safe, though I
> didn't dig through all the callers).

Right. The point is that we should be respecting "eol" here in the first
place. Plus the final result is the character _after_ the '>'. Plus when
it returns NULL, you'd want to leave "eol" untouched (stripping
nothing).

So yeah, I'm sure it could be rewritten around memrchr() or something,
but I doubt it would be much shorter, and the chance of introducing an
off-by-one seems non-trivial. :)

-Peff

  parent reply	other threads:[~2021-09-21  5:43 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21  3:45 [PATCH 0/5] const-correctness in grep.c Jeff King
2021-09-21  3:46 ` [PATCH 1/5] grep: stop modifying buffer in strip_timestamp Jeff King
2021-09-21  5:18   ` Carlo Arenas
2021-09-21  5:24     ` Eric Sunshine
2021-09-21  5:40       ` Carlo Arenas
2021-09-21  5:43       ` Jeff King [this message]
2021-09-21  6:42         ` Carlo Marcelo Arenas Belón
2021-09-21  7:37           ` René Scharfe
2021-09-21 14:24             ` Jeff King
2021-09-21 21:02               ` Ævar Arnfjörð Bjarmason
2021-09-22 20:20                 ` Jeff King
2021-09-23  0:53                   ` Ævar Arnfjörð Bjarmason
2021-09-21  3:48 ` [PATCH 2/5] grep: stop modifying buffer in show_line() Jeff King
2021-09-21  4:22   ` Taylor Blau
2021-09-21  4:42     ` Jeff King
2021-09-21  4:45       ` Taylor Blau
2021-09-21  3:48 ` [PATCH 3/5] grep: stop modifying buffer in grep_source_1() Jeff King
2021-09-21  3:49 ` [PATCH 4/5] grep: mark "haystack" buffers as const Jeff King
2021-09-21 12:04   ` Ævar Arnfjörð Bjarmason
2021-09-21 14:27     ` Jeff King
2021-09-21  3:51 ` [PATCH 5/5] grep: store grep_source buffer " Jeff King
2021-09-21  4:30 ` [PATCH 0/5] const-correctness in grep.c Taylor Blau
2021-09-21 12:07 ` Ævar Arnfjörð Bjarmason
2021-09-21 14:49   ` Jeff King
2021-09-21 12:45 ` [PATCH 6/5] grep.c: mark eol/bol and derived as "const char * const" Ævar Arnfjörð Bjarmason
2021-09-21 14:53   ` Jeff King
2021-09-21 15:17     ` Ævar Arnfjörð Bjarmason
2021-09-21 19:18       ` Jeff King
2021-09-23 13:56         ` Ævar Arnfjörð Bjarmason
2021-09-24  4:22           ` Junio C Hamano
2021-09-22 19:02     ` Junio C Hamano
2021-09-22 18:57 ` [PATCH 0/5] const-correctness in grep.c Junio C Hamano

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