Teach GNU grep(1)'s '-o' ('--only-matching') to 'git-grep'. This option
prints only the matching components of each line. It writes multiple
lines if more than one match exists on a given line.
For example:
$ /git grep -on --column git -- README.md | head -3
README.md:15:56:git
README.md:18:20:git
README.md:19:16:git
By using show_line_header(), 'git grep --only-matching' correctly
respects the '--heading' option:
$ git grep -on --column --heading git -- README.md | head -4
README.md
15:56:git
18:20:git
19:16:git
We mirror GNU grep's behavior when given -A, -B, or -C with
--only-matching, by displaying only the matching portion(s) of a line,
ignoring contextual line(s), but displaying '--' (context separator)
line(s).
Notably: when show_line() is called on a line that contains _multiple_
matches, we keep track of a relative offset from the beginning of the
line and increment 'cno' in subsequent calls to show_line_header() when
the expression is not extended. In the extended case, we do not do this,
because the column of the first match is undefined, thus relative
offsets are meaningless.
Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
---
Documentation/git-grep.txt | 6 +++-
builtin/grep.c | 1 +
grep.c | 34 +++++++++++++++++--
grep.h | 1 +
t/t7810-grep.sh | 69 ++++++++++++++++++++++++++++++++++++++
5 files changed, 107 insertions(+), 4 deletions(-)
diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index c48a578cb1..5c09abec4a 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -20,7 +20,7 @@ SYNOPSIS
[-c | --count] [--all-match] [-q | --quiet]
[--max-depth <depth>]
[--color[=<when>] | --no-color]
- [--break] [--heading] [-p | --show-function]
+ [--break] [--heading] [-o | --only-matching] [-p | --show-function]
[-A <post-context>] [-B <pre-context>] [-C <context>]
[-W | --function-context]
[--threads <num>]
@@ -223,6 +223,10 @@ providing this option will cause it to die.
Show the filename above the matches in that file instead of
at the start of each shown line.
+--o::
+--only-matching::
+ Prints only the matching part of the lines.
+
-p::
--show-function::
Show the preceding line that contains the function name of
diff --git a/builtin/grep.c b/builtin/grep.c
index f9f516dfc4..0507ac335a 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -851,6 +851,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
N_("print empty line between matches from different files")),
OPT_BOOL(0, "heading", &opt.heading,
N_("show filename only once above matches from same file")),
+ OPT_BOOL('o', "only-matching", &opt.only_matching, N_("show only matches")),
OPT_GROUP(""),
OPT_CALLBACK('C', "context", &opt, N_("n"),
N_("show <n> context lines before and after matches"),
diff --git a/grep.c b/grep.c
index 36bf7cf08d..9297fde643 100644
--- a/grep.c
+++ b/grep.c
@@ -1422,12 +1422,24 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
opt->output(opt, "\n", 1);
}
}
+ if (opt->only_matching && sign != ':') {
+ /*
+ * If we're given '--only-matching' and the line is a contextual
+ * one (i.e., we're given '-A', '-B', or '-C'), mark the line as
+ * shown (to advance opt->last_shown), but do not show it (since
+ * we are given '--only-matching').
+ */
+ opt->last_shown = lno;
+ return;
+ }
show_line_header(opt, name, lno, cno, sign);
- if (opt->color) {
+ if (opt->color || opt->only_matching) {
regmatch_t match;
enum grep_context ctx = GREP_CONTEXT_BODY;
int ch = *eol;
int eflags = 0;
+ int first = 1;
+ int offset = 1;
if (sign == ':')
match_color = opt->color_match_selected;
@@ -1444,16 +1456,32 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
if (match.rm_so == match.rm_eo)
break;
- output_color(opt, bol, match.rm_so, line_color);
+ if (!opt->only_matching) {
+ output_color(opt, bol, match.rm_so, line_color);
+ } else if (!first) {
+ /*
+ * We are given --only-matching, and this is not
+ * the first match on a line. Reprint the
+ * newline and header before showing another
+ * match.
+ */
+ opt->output(opt, "\n", 1);
+ show_line_header(opt, name, lno,
+ opt->extended ? 0 : offset+match.rm_so,
+ sign);
+ }
output_color(opt, bol + match.rm_so,
match.rm_eo - match.rm_so, match_color);
+ offset += match.rm_eo;
bol += match.rm_eo;
rest -= match.rm_eo;
eflags = REG_NOTBOL;
+ first = 0;
}
*eol = ch;
}
- output_color(opt, bol, rest, line_color);
+ if (!opt->only_matching)
+ output_color(opt, bol, rest, line_color);
opt->output(opt, "\n", 1);
}
diff --git a/grep.h b/grep.h
index 08a0b391c5..24c1460100 100644
--- a/grep.h
+++ b/grep.h
@@ -126,6 +126,7 @@ struct grep_opt {
const char *prefix;
int prefix_length;
regex_t regexp;
+ int only_matching;
int linenum;
int columnnum;
int invert;
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 491b2e044a..6251ae678a 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -1432,6 +1432,75 @@ test_expect_success 'grep --heading' '
test_cmp expected actual
'
+test_expect_success 'grep --only-matching' '
+ cat >expected <<-\EOF &&
+ file:1:5:mmap
+ file:2:5:mmap
+ file:3:5:mmap
+ file:3:14:mmap
+ file:4:5:mmap
+ file:4:14:mmap
+ file:5:5:mmap
+ file:5:14:mmap
+ EOF
+ git grep --only-matching --line-number --column mmap file >actual &&
+ test_cmp expected actual
+'
+
+test_expect_success 'grep --only-matching --column (unsupported)' '
+ cat >expected <<-\EOF &&
+ file:mmap
+ file:mmap
+ file:mmap
+ file:mmap
+ file:mmap
+ file:mmap
+ file:mmap
+ file:mmap
+ EOF
+ git grep --only-matching --column --not --not -e mmap -- file >actual &&
+ test_cmp expected actual
+'
+
+test_expect_success 'grep --only-matching -C' '
+ cat >expected <<-\EOF &&
+ hello.ps1:function
+ hello.ps1:function
+ --
+ hello.ps1:function
+ EOF
+ git grep --only-matching -C1 function hello.ps1 >actual &&
+ test_cmp expected actual
+'
+
+test_expect_success 'grep --only-matching --heading' '
+ cat >expected <<-\EOF &&
+ file
+ 1:5:mmap
+ 2:5:mmap
+ 3:5:mmap
+ 3:14:mmap
+ 4:5:mmap
+ 4:14:mmap
+ 5:5:mmap
+ 5:14:mmap
+ EOF
+ git grep --only-matching --heading --line-number --column mmap file >actual &&
+ test_cmp expected actual
+'
+
+test_expect_success 'grep --only-matching -i' '
+ cat >expected <<-\EOF &&
+ hello_world:1:1:Hello
+ hello_world:2:1:HeLLo
+ hello_world:3:1:Hello
+ hello_world:4:1:HeLLo
+ EOF
+ git grep --only-matching --line-number --column \
+ -i hello hello_world >actual &&
+ test_cmp expected actual
+'
+
cat >expected <<EOF
<BOLD;GREEN>hello.c<RESET>
4:int main(int argc, const <BLACK;BYELLOW>char<RESET> **argv)
--
2.17.0
