Re: [PATCH] grep: fix colouring of matches with zero length
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Jun 1, 2009, 21:17 UTC
- Message-ID
- <7voct7k61r.fsf@alter.siamese.dyndns.org>
- In-Reply-To
- <4A2405DA.7010801@lsrfire.ath.cx>
René Scharfe <rene.scharfe@lsrfire.ath.cx> writes:
> The first hunk fixes match colouring if the patterns is the empty string. > Such a pattern matches the whole line,...
Hmmm...
An empty pattern may have to produce a match with any line, but I do not think it should match the whole line. GNU seems to agree with me.
echo foo | grep --color -e ''
echo foo | grep --color -F -e ''
echo foo | grep --color -e '.*'
echo foo | grep --color -F -e 'foo'The first two are uncoloured (but still show matches).
> The second hunk of the patch makes sure that grep match colouring doesn't > get stuck in an infinite loop if the length of a match is zero.
Certainly we need to advance the match pointer, and this issue needs to be addressed. I think it is a good change.
Show 37 quoted lines
> of the line is simply printed without colouring. Even though the empty
> pattern string doesn't result in empty matches any more, this defensive
> measure catches unknown cases.
>
> Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
> ---
> grep.c | 8 +++++++-
> 1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/grep.c b/grep.c
> index cc6d5b0..745b3c0 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -324,7 +324,11 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
> }
>
> again:
> - if (p->fixed)
> + if (p->pattern[0] == '\0') {
> + hit = 1;
> + pmatch[0].rm_so = 0;
> + pmatch[0].rm_eo = eol - bol;
> + } else if (p->fixed)
> hit = !fixmatch(p->pattern, bol, pmatch);
> else
> hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
> @@ -500,6 +504,8 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
>
> *eol = '\0';
> while (next_match(opt, bol, eol, ctx, &match, eflags)) {
> + if (match.rm_so == match.rm_eo)
> + break;
> printf("%.*s%s%.*s%s",
> (int)match.rm_so, bol,
> opt->color_match,
> --
> 1.6.3.1