[RFC PATCH 2/3] grep: prepare grep for submodules

[Chris Packham <judge.packham@gmail.com>]

Add --submodule-prefix option to pass to subprocess grep invocations. The
prefix is then used when outputting the results.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
---
 builtin/grep.c |    2 ++
 grep.c         |    8 ++++++++
 grep.h         |    1 +
 3 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/builtin/grep.c b/builtin/grep.c
index da32f3d..8315ff0 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -927,6 +927,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			    "allow calling of grep(1) (ignored by this build)"),
 		{ OPTION_CALLBACK, 0, "help-all", &options, NULL, "show usage",
 		  PARSE_OPT_HIDDEN | PARSE_OPT_NOARG, help_callback },
+		OPT_STRING(0, "submodule-prefix", &opt.submodule_prefix, "DIR",
+			"prepend this to submodule path output"),
 		OPT_END()
 	};
 
diff --git a/grep.c b/grep.c
index 63c4280..36bec98 100644
--- a/grep.c
+++ b/grep.c
@@ -370,6 +370,10 @@ static void output_sep(struct grep_opt *opt, char sign)
 
 static void show_name(struct grep_opt *opt, const char *name)
 {
+	if (opt->submodule_prefix) {
+		output_color(opt, opt->submodule_prefix,
+			strlen(opt->submodule_prefix), opt->color_filename);
+	}
 	output_color(opt, name, strlen(name), opt->color_filename);
 	opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 }
@@ -644,6 +648,10 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 	}
 	opt->last_shown = lno;
 
+	if (opt->submodule_prefix) {
+		output_color(opt, opt->submodule_prefix,
+			strlen(opt->submodule_prefix), opt->color_filename);
+	}
 	if (opt->pathname) {
 		output_color(opt, name, strlen(name), opt->color_filename);
 		output_sep(opt, sign);
diff --git a/grep.h b/grep.h
index 06621fe..d918da4 100644
--- a/grep.h
+++ b/grep.h
@@ -67,6 +67,7 @@ struct grep_opt {
 	struct grep_expr *pattern_expression;
 	const char *prefix;
 	int prefix_length;
+	const char *submodule_prefix;
 	regex_t regexp;
 	int linenum;
 	int invert;
-- 
1.7.3.dirty