[PATCH][RFC] grep: add color.grep.matchcontext and color.grep.matchselected

["René Scharfe" <l.s.r@web.de>]

The config option color.grep.match can be used to specify the highlighting
color for matching strings.  Add the options matchContext and matchSelected
to allow different colors to be specified for matching strings in the
context vs. in selected lines.  This is similar to the ms and mc specifiers
in GNU grep's environment variable GREP_COLORS.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
Only *very* lightly tested, and a test for t/is missing anyway.  Just
wanted to quickly show what I meant.  You'd set color.grep.matchContext=""
to turn off highlighting in context lines.  What do you think?

 Documentation/config.txt |  6 +++++-
 grep.c                   | 29 ++++++++++++++++++++++-------
 grep.h                   |  3 ++-
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 8b49813..78832ae 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -885,7 +885,11 @@ color.grep.<slot>::
 `linenumber`;;
 	line number prefix (when using `-n`)
 `match`;;
-	matching text
+	matching text (same as setting `matchContext` and `matchSelected`)
+`matchContext`;;
+	matching text in context lines
+`matchSelected`;;
+	matching text in selected lines
 `selected`;;
 	non-matching text in selected lines
 `separator`;;
diff --git a/grep.c b/grep.c
index 4dc31ea..6e085f8 100644
--- a/grep.c
+++ b/grep.c
@@ -35,7 +35,8 @@ void init_grep_defaults(void)
 	strcpy(opt->color_filename, "");
 	strcpy(opt->color_function, "");
 	strcpy(opt->color_lineno, "");
-	strcpy(opt->color_match, GIT_COLOR_BOLD_RED);
+	strcpy(opt->color_match_context, GIT_COLOR_BOLD_RED);
+	strcpy(opt->color_match_selected, GIT_COLOR_BOLD_RED);
 	strcpy(opt->color_selected, "");
 	strcpy(opt->color_sep, GIT_COLOR_CYAN);
 	opt->color = -1;
@@ -101,12 +102,22 @@ int grep_config(const char *var, const char *value, void *cb)
 		color = opt->color_function;
 	else if (!strcmp(var, "color.grep.linenumber"))
 		color = opt->color_lineno;
-	else if (!strcmp(var, "color.grep.match"))
-		color = opt->color_match;
+	else if (!strcmp(var, "color.grep.matchcontext"))
+		color = opt->color_match_context;
+	else if (!strcmp(var, "color.grep.matchselected"))
+		color = opt->color_match_selected;
 	else if (!strcmp(var, "color.grep.selected"))
 		color = opt->color_selected;
 	else if (!strcmp(var, "color.grep.separator"))
 		color = opt->color_sep;
+	else if (!strcmp(var, "color.grep.match")) {
+		int rc = 0;
+		if (!value)
+			return config_error_nonbool(var);
+		rc |= color_parse(value, opt->color_match_context);
+		rc |= color_parse(value, opt->color_match_selected);
+		return rc;
+	}
 
 	if (color) {
 		if (!value)
@@ -144,7 +155,8 @@ void grep_init(struct grep_opt *opt, const char *prefix)
 	strcpy(opt->color_filename, def->color_filename);
 	strcpy(opt->color_function, def->color_function);
 	strcpy(opt->color_lineno, def->color_lineno);
-	strcpy(opt->color_match, def->color_match);
+	strcpy(opt->color_match_context, def->color_match_context);
+	strcpy(opt->color_match_selected, def->color_match_selected);
 	strcpy(opt->color_selected, def->color_selected);
 	strcpy(opt->color_sep, def->color_sep);
 }
@@ -1084,7 +1096,7 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 		      const char *name, unsigned lno, char sign)
 {
 	int rest = eol - bol;
-	char *line_color = NULL;
+	const char *match_color, *line_color = NULL;
 
 	if (opt->file_break && opt->last_shown == 0) {
 		if (opt->show_hunk_mark)
@@ -1123,6 +1135,10 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 		int eflags = 0;
 
 		if (sign == ':')
+			match_color = opt->color_match_selected;
+		else
+			match_color = opt->color_match_context;
+		if (sign == ':')
 			line_color = opt->color_selected;
 		else if (sign == '-')
 			line_color = opt->color_context;
@@ -1135,8 +1151,7 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 
 			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);
+				     match.rm_eo - match.rm_so, match_color);
 			bol += match.rm_eo;
 			rest -= match.rm_eo;
 			eflags = REG_NOTBOL;
diff --git a/grep.h b/grep.h
index eaaced1..95f197a 100644
--- a/grep.h
+++ b/grep.h
@@ -124,7 +124,8 @@ struct grep_opt {
 	char color_filename[COLOR_MAXLEN];
 	char color_function[COLOR_MAXLEN];
 	char color_lineno[COLOR_MAXLEN];
-	char color_match[COLOR_MAXLEN];
+	char color_match_context[COLOR_MAXLEN];
+	char color_match_selected[COLOR_MAXLEN];
 	char color_selected[COLOR_MAXLEN];
 	char color_sep[COLOR_MAXLEN];
 	int regflags;
-- 
2.1.2