[PATCH/RFC] grep: optionally show only the match

[Marcus Karlsson <mk@acc.umu.se>]

Make git-grep optionally omit the parts of the line before and after the
match.

Signed-off-by: Marcus Karlsson <mk@acc.umu.se>
---
 Documentation/git-grep.txt | 8 +++++++-
 builtin/grep.c             | 2 ++
 grep.c                     | 7 +++++--
 grep.h                     | 1 +
 4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index cfecf84..6ef22cb 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -20,7 +20,8 @@ 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]
 	   [-f <file>] [-e] <pattern>
@@ -183,6 +184,11 @@ OPTIONS
 	Show the filename above the matches in that file instead of
 	at the start of each shown line.
 
+-o::
+--only-matching::
+	Show only the part of the matching line that matched the
+	pattern.
+
 -p::
 --show-function::
 	Show the preceding line that contains the function name of
diff --git a/builtin/grep.c b/builtin/grep.c
index 09ca4c9..56aba7b 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -782,6 +782,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			N_("print empty line between matches from different files")),
 		OPT_BOOLEAN(0, "heading", &opt.heading,
 			N_("show filename only once above matches from same file")),
+		OPT_BOOLEAN('o', "only-matching", &opt.only_matching,
+			N_("show only the matching part of a matched line")),
 		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 04e3ec6..9fc888e 100644
--- a/grep.c
+++ b/grep.c
@@ -827,7 +827,9 @@ 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 == 0)
+				output_color(opt, bol, match.rm_so,
+					     line_color);
 			output_color(opt, bol + match.rm_so,
 				     match.rm_eo - match.rm_so,
 				     opt->color_match);
@@ -837,7 +839,8 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 		}
 		*eol = ch;
 	}
-	output_color(opt, bol, rest, line_color);
+	if (opt->only_matching == 0)
+		output_color(opt, bol, rest, line_color);
 	opt->output(opt, "\n", 1);
 }
 
diff --git a/grep.h b/grep.h
index 75afb7b..4163102 100644
--- a/grep.h
+++ b/grep.h
@@ -127,6 +127,7 @@ struct grep_opt {
 	int show_hunk_mark;
 	int file_break;
 	int heading;
+	int only_matching;
 	void *priv;
 
 	void (*output)(struct grep_opt *opt, const void *data, size_t size);
-- 
1.7.12.289.g0ce9864.dirty