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From: Brandon Williams <bmwill@google.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
	"Jeff King" <peff@peff.net>,
	"Jeffrey Walton" <noloader@gmail.com>,
	"Michał Kiedrowicz" <michal.kiedrowicz@gmail.com>,
	"J Smith" <dark.panda@gmail.com>,
	"Victor Leschuk" <vleschuk@gmail.com>,
	"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
	"Fredrik Kuivinen" <frekui@gmail.com>
Subject: Re: [PATCH 21/29] grep: factor test for \0 in grep patterns into a function
Date: Thu, 11 May 2017 13:15:17 -0700	[thread overview]
Message-ID: <20170511201517.GI83655@google.com> (raw)
In-Reply-To: <20170511091829.5634-22-avarab@gmail.com>

On 05/11, Ævar Arnfjörð Bjarmason wrote:
> Factor the test for \0 in grep patterns into a function. Since commit
> 9eceddeec6 ("Use kwset in grep", 2011-08-21) any pattern containing a
> \0 is considered fixed as regcomp() can't handle it.
> 
> This limitation was never documented, and other some regular
> expression engines are capable of compiling a pattern containing a
> \0. Factoring this out makes a subsequent change which does that
> smaller.
> 
> See a previous commit in this series ("grep: add tests to fix blind
> spots with \0 patterns", 2017-04-21) for further details & rationale.
> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  grep.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/grep.c b/grep.c
> index bf6c2494fd..27de615209 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -394,12 +394,6 @@ static int is_fixed(const char *s, size_t len)
>  {
>  	size_t i;
>  
> -	/* regcomp cannot accept patterns with NULs so we
> -	 * consider any pattern containing a NUL fixed.
> -	 */
> -	if (memchr(s, 0, len))
> -		return 1;
> -
>  	for (i = 0; i < len; i++) {
>  		if (is_regex_special(s[i]))
>  			return 0;
> @@ -408,6 +402,17 @@ static int is_fixed(const char *s, size_t len)
>  	return 1;
>  }
>  
> +static int has_null(const char *s, size_t len)
> +{
> +	/* regcomp cannot accept patterns with NULs so when using it
> +	 * we consider any pattern containing a NUL fixed.
> +	 */

I commented on a later patch but really the comment should be fixed
here.  And why not simply move this to where you intend it to be at the
end of the series now?

> +	if (memchr(s, 0, len))
> +		return 1;
> +
> +	return 0;
> +}
> +
>  static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)
>  {
>  	struct strbuf sb = STRBUF_INIT;
> @@ -451,7 +456,7 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
>  	 * simple string match using kws.  p->fixed tells us if we
>  	 * want to use kws.
>  	 */
> -	if (opt->fixed || is_fixed(p->pattern, p->patternlen))
> +	if (opt->fixed || has_null(p->pattern, p->patternlen) || is_fixed(p->pattern, p->patternlen))
>  		p->fixed = !icase || ascii_only;
>  	else
>  		p->fixed = 0;
> -- 
> 2.11.0
> 

-- 
Brandon Williams

  reply	other threads:[~2017-05-11 20:15 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-11  9:18 [PATCH 00/29] Easy to review grep & pre-PCRE changes Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 01/29] Makefile & configure: reword inaccurate comment about PCRE Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 02/29] grep & rev-list doc: stop promising libpcre for --perl-regexp Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 03/29] test-lib: rename the LIBPCRE prerequisite to PCRE Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 04/29] log: add exhaustive tests for pattern style options & config Ævar Arnfjörð Bjarmason
2017-05-12  4:48   ` Junio C Hamano
2017-05-13 18:02     ` Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 05/29] grep: add a test asserting that --perl-regexp dies when !PCRE Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 06/29] grep: add a test for backreferences in PCRE patterns Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 07/29] grep: change non-ASCII -i test to stop using --debug Ævar Arnfjörð Bjarmason
2017-05-11 18:31   ` Brandon Williams
2017-05-11 18:35     ` Ævar Arnfjörð Bjarmason
2017-05-11 20:05       ` Brandon Williams
2017-05-11  9:18 ` [PATCH 08/29] grep: add tests for --threads=N and grep.threads Ævar Arnfjörð Bjarmason
2017-05-11 18:36   ` Brandon Williams
2017-05-11 19:22     ` Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 09/29] grep: amend submodule recursion test for regex engine testing Ævar Arnfjörð Bjarmason
2017-05-12  4:59   ` Junio C Hamano
2017-05-13 17:33     ` Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 10/29] grep: add tests for grep pattern types being passed to submodules Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 11/29] grep: add a test helper function for less verbose -f \0 tests Ævar Arnfjörð Bjarmason
2017-05-12  5:06   ` Junio C Hamano
2017-05-13 11:33     ` Ævar Arnfjörð Bjarmason
2017-05-15  1:29       ` Junio C Hamano
2017-05-11  9:18 ` [PATCH 12/29] grep: prepare for testing binary regexes containing rx metacharacters Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 13/29] grep: add tests to fix blind spots with \0 patterns Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 14/29] perf: add a GIT_PERF_MAKE_COMMAND for when *_MAKE_OPTS won't do Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 15/29] perf: emit progress output when unpacking & building Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 16/29] perf: add a performance comparison test of grep -G, -E and -P Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 17/29] perf: add a performance comparison of fixed-string grep Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 18/29] grep: catch a missing enum in switch statement Ævar Arnfjörð Bjarmason
2017-05-11 20:08   ` Brandon Williams
2017-05-11 20:40     ` Stefan Beller
2017-05-11 20:50       ` Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 19/29] grep: remove redundant regflags assignment under PCRE Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 20/29] grep: remove redundant `regflags &= ~REG_EXTENDED` assignments Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 21/29] grep: factor test for \0 in grep patterns into a function Ævar Arnfjörð Bjarmason
2017-05-11 20:15   ` Brandon Williams [this message]
2017-05-11 20:22     ` Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 22/29] grep: change the internal PCRE macro names to be PCRE1 Ævar Arnfjörð Bjarmason
2017-05-11 20:10   ` Brandon Williams
2017-05-11  9:18 ` [PATCH 23/29] grep: change internal *pcre* variable & function names to be *pcre1* Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 24/29] grep: move two functions to avoid forward declaration Ævar Arnfjörð Bjarmason
2017-05-11 20:14   ` Brandon Williams
2017-05-11 20:20     ` Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 25/29] test-lib: add a PTHREADS prerequisite Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 26/29] pack-objects & index-pack: add test for --threads warning Ævar Arnfjörð Bjarmason
2017-05-11 20:17   ` Brandon Williams
2017-05-11 20:34     ` Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 27/29] pack-objects: fix buggy warning about threads Ævar Arnfjörð Bjarmason
2017-05-11  9:18 ` [PATCH 28/29] grep: given --threads with NO_PTHREADS=YesPlease, warn Ævar Arnfjörð Bjarmason
2017-05-11 20:21   ` Brandon Williams
2017-05-11 20:33     ` Ævar Arnfjörð Bjarmason
2017-05-11 20:43       ` Brandon Williams
2017-05-11 21:20         ` [PATCH] C style: use standard style for "TRANSLATORS" comments Ævar Arnfjörð Bjarmason
2017-05-11 21:41           ` Jonathan Nieder
2017-05-11 21:50             ` Brandon Williams
2017-05-12  5:20           ` Johannes Sixt
2017-05-30 16:02           ` Jiang Xin
2017-05-30 23:03             ` Junio C Hamano
2017-05-11  9:18 ` [PATCH 29/29] grep: assert that threading is enabled when calling grep_{lock,unlock} Ævar Arnfjörð Bjarmason

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