Re: [PATCH v2] grep: add --max-count command line option
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Jun 21, 2022, 16:27 UTC
- Message-ID
- <xmqq5ykuhthp.fsf@gitster.g>
- In-Reply-To
- <pull.1278.v2.git.git.1655789777023.gitgitgadget@gmail.com>
"Carlos L. via GitGitGadget" <gitgitgadget@gmail.com> writes:
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> From: =?UTF-8?q?Carlos=20L=C3=B3pez?= <00xc@protonmail.com> > > This patch adds a command line option analogous to that of GNU > grep(1)'s -m / --max-count, which users might already be used to. > This makes it possible to limit the amount of matches shown in the > output while keeping the functionality of other options such as -C > (show code context) or -p (show containing function), which would be > difficult to do with a shell pipeline (e.g. head(1)). > > Signed-off-by: Carlos López 00xc@protonmail.com > --- > ... > Documentation/git-grep.txt | 8 ++++++++ > builtin/grep.c | 9 +++++++++ > grep.c | 2 ++ > grep.h | 2 ++ > 4 files changed, 21 insertions(+)
Tests?
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> diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt > index 3d393fbac1b..19b817d5e58 100644 > --- a/Documentation/git-grep.txt > +++ b/Documentation/git-grep.txt > @@ -23,6 +23,7 @@ SYNOPSIS > [--break] [--heading] [-p | --show-function] > [-A <post-context>] [-B <pre-context>] [-C <context>] > [-W | --function-context] > + [(-m | --max-count) <num>] > [--threads <num>] > [-f <file>] [-e] <pattern> > [--and|--or|--not|(|)|-e <pattern>...] > @@ -238,6 +239,13 @@ providing this option will cause it to die. > `git diff` works out patch hunk headers (see 'Defining a > custom hunk-header' in linkgit:gitattributes[5]). > > +-m <num>:: > +--max-count <num>:: > + Limit the amount of matches per file. When using the `-v` or > + `--invert-match` option, the search stops after the specified > + number of non-matches. A value of -1 will return unlimited > + results (the default).
Hmph ...
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> + /* > + * Optimize out the case where the amount of matches is limited to zero. > + * We do this to keep results consistent with GNU grep(1). > + */ > + if (opt.max_count == 0) > + exit(EXIT_FAILURE); > +
OK, so "stop before seeing any match" logically leads to "we found nothing, so exit with non-zero".
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> diff --git a/grep.c b/grep.c > index 82eb7da1022..b32ab75cb6b 100644 > --- a/grep.c > +++ b/grep.c > @@ -1686,6 +1686,8 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle > bol = eol + 1; > if (!left) > break; > + if (opt->max_count != -1 && count == opt->max_count) > + break;
I would have written it "if (0 <= opt->max_count && ...)". What happens when a trickster asks you to do "git grep -m -2"?
I guess what I am getting at is if we are better off saying that negative means unlimited, instead of special casing -1 like this. I didn't think it through so it may be perfectly possible that what you wrote makes more sense than "anything negative is unlimited".
I dunno.
> left--; > lno++; > }
Thanks.
Show 22 quoted lines
> diff --git a/grep.h b/grep.h
> index c722d25ed9d..bdcadce61b8 100644
> --- a/grep.h
> +++ b/grep.h
> @@ -171,6 +171,7 @@ struct grep_opt {
> int show_hunk_mark;
> int file_break;
> int heading;
> + int max_count;
> void *priv;
>
> void (*output)(struct grep_opt *opt, const void *data, size_t size);
> @@ -181,6 +182,7 @@ struct grep_opt {
> .relative = 1, \
> .pathname = 1, \
> .max_depth = -1, \
> + .max_count = -1, \
> .pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED, \
> .colors = { \
> [GREP_COLOR_CONTEXT] = "", \
>
> base-commit: 5b71c59bc3b9365075e2a175aa7b6f2b0c84ce44