From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 12 Jan 2010 08:56:15 +0000 (-0800)
Subject: Merge branch 'jc/maint-1.6.4-grep-lookahead' into jc/maint-grep-lookahead
X-Git-Tag: v1.7.0-rc0~64^2~4
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=e2d2e383d87dcbcd296ca9f21f3c8b7ef853c928;p=git.git

Merge branch 'jc/maint-1.6.4-grep-lookahead' into jc/maint-grep-lookahead

* jc/maint-1.6.4-grep-lookahead:
  grep: optimize built-in grep by skipping lines that do not hit

This needs to be an evil merge as fixmatch() changed signature since
5183bf6 (grep: Allow case insensitive search of fixed-strings,
2009-11-06).

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

e2d2e383d87dcbcd296ca9f21f3c8b7ef853c928
diff --cc grep.c
index bdadf2c0c,03ffcd404..62723da13
--- a/grep.c
+++ b/grep.c
@@@ -615,6 -608,65 +615,65 @@@ static void show_pre_context(struct gre
  	}
  }
  
+ static int should_lookahead(struct grep_opt *opt)
+ {
+ 	struct grep_pat *p;
+ 
+ 	if (opt->extended)
+ 		return 0; /* punt for too complex stuff */
+ 	if (opt->invert)
+ 		return 0;
+ 	for (p = opt->pattern_list; p; p = p->next) {
+ 		if (p->token != GREP_PATTERN)
+ 			return 0; /* punt for "header only" and stuff */
+ 	}
+ 	return 1;
+ }
+ 
+ static int look_ahead(struct grep_opt *opt,
+ 		      unsigned long *left_p,
+ 		      unsigned *lno_p,
+ 		      char **bol_p)
+ {
+ 	unsigned lno = *lno_p;
+ 	char *bol = *bol_p;
+ 	struct grep_pat *p;
+ 	char *sp, *last_bol;
+ 	regoff_t earliest = -1;
+ 
+ 	for (p = opt->pattern_list; p; p = p->next) {
+ 		int hit;
+ 		regmatch_t m;
+ 
+ 		if (p->fixed)
 -			hit = !fixmatch(p->pattern, bol, &m);
++			hit = !fixmatch(p->pattern, bol, p->ignore_case, &m);
+ 		else
+ 			hit = !regexec(&p->regexp, bol, 1, &m, 0);
+ 		if (!hit || m.rm_so < 0 || m.rm_eo < 0)
+ 			continue;
+ 		if (earliest < 0 || m.rm_so < earliest)
+ 			earliest = m.rm_so;
+ 	}
+ 
+ 	if (earliest < 0) {
+ 		*bol_p = bol + *left_p;
+ 		*left_p = 0;
+ 		return 1;
+ 	}
+ 	for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
+ 		; /* find the beginning of the line */
+ 	last_bol = sp;
+ 
+ 	for (sp = bol; sp < last_bol; sp++) {
+ 		if (*sp == '\n')
+ 			lno++;
+ 	}
+ 	*left_p -= last_bol - bol;
+ 	*bol_p = last_bol;
+ 	*lno_p = lno;
+ 	return 0;
+ }
+ 
  static int grep_buffer_1(struct grep_opt *opt, const char *name,
  			 char *buf, unsigned long size, int collect_hits)
  {