Re: [PATCH 2/2] grep: don't call regexec() for fixed strings

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 10, 2009, 20:37 UTC
Message-ID: <7vbpuex5hm.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <4967DB4A.2000702@lsrfire.ath.cx>

René Scharfe <rene.scharfe@lsrfire.ath.cx> writes:

Show 6 quoted lines

> Add the new flag "fixed" to struct grep_pat and set it if the pattern
> is doesn't contain any regex control characters in addition to if the
> flag -F/--fixed-strings was specified.
>
> This gives a nice speed up on msysgit, where regexec() seems to be
> extra slow.  Before (best of five runs):

Thanks, and...

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>  static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
>  {
> -	int err = regcomp(&p->regexp, p->pattern, opt->regflags);
> +	int err;
> +
> +	if (opt->fixed || is_fixed(p->pattern))
> +		p->fixed = 1;
> +	if (opt->regflags & REG_ICASE)
> +		p->fixed = 0;

... thanks again for being extra careful. That's why I *love* your patches.