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[PATCH 5/5] grep: add support for coloring with external greps

From
René Scharfe <rene.scharfe@lsrfire.ath.cx>
Date
Mar 7, 2009, 12:34 UTC
Message-ID
<1236429286.6486.52.camel@ubuntu.ubuntu-domain>
In-Reply-To
<1236428699.6486.41.camel@ubuntu.ubuntu-domain>

Add the config variable color.grep.external, which can be used to switch on coloring of external greps. To enable auto coloring with GNU grep, one needs to set color.grep.external to --color=always to defeat the pager started by git grep. The value of the config variable will be passed to the external grep only if it would colorize internal grep's output, so automatic terminal detected works. The default is to not pass any option, because the external grep command could be a program without color support.

Also set the environment variables GREP_COLOR and GREP_COLORS to pass the configured color for matches to the external grep. This works with GNU grep; other variables could be added as needed.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
---
 Documentation/config.txt |   12 +++++++++++-
 builtin-grep.c           |   36 ++++++++++++++++++++++++++++++++++++
 grep.h                   |    1 +
 3 files changed, 48 insertions(+), 1 deletions(-)
diff --git a/Documentation/config.txt b/Documentation/config.txt
index b75dada..4d42bff 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -553,9 +553,19 @@ color.grep::
 	`never`), never.  When set to `true` or `auto`, use color only
 	when the output is written to the terminal.  Defaults to `false`.
 
+color.grep.external::
+	The string value of this variable is passed to an external 'grep'
+	command as a command line option if match highlighting is turned
+	on.  If set to an empty string, no option is passed at all,
+	turning off coloring for external 'grep' calls; this is the default.
+	For GNU grep, set it to `--color=always` to highlight matches even
+	when a pager is used.
+
 color.grep.match::
 	Use customized color for matches.  The value of this variable
-	may be specified as in color.branch.<slot>.
+	may be specified as in color.branch.<slot>.  It is passed using
+	the environment variables 'GREP_COLOR' and 'GREP_COLORS' when
+	calling an external 'grep'.
 
 color.interactive::
 	When set to `always`, always use colors for interactive prompts
diff --git a/builtin-grep.c b/builtin-grep.c
index e2c0f01..9e7e766 100644
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -30,6 +30,10 @@ static int grep_config(const char *var, const char *value, void *cb)
 		opt->color = git_config_colorbool(var, value, -1);
 		return 0;
 	}
+	if (!strcmp(var, "grep.color.external") ||
+	    !strcmp(var, "color.grep.external")) {
+		return git_config_string(&(opt->color_external), var, value);
+	}
 	if (!strcmp(var, "grep.color.match") ||
 	    !strcmp(var, "color.grep.match")) {
 		if (!value)
@@ -287,6 +291,21 @@ static int flush_grep(struct grep_opt *opt,
 	return status;
 }
 
+static void grep_add_color(struct strbuf *sb, const char *escape_seq)
+{
+	size_t orig_len = sb->len;
+
+	while (*escape_seq) {
+		if (*escape_seq == 'm')
+			strbuf_addch(sb, ';');
+		else if (*escape_seq != '\033' && *escape_seq  != '[')
+			strbuf_addch(sb, *escape_seq);
+		escape_seq++;
+	}
+	if (sb->len > orig_len && sb->buf[sb->len - 1] == ';')
+		strbuf_setlen(sb, sb->len - 1);
+}
+
 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 {
 	int i, nr, argc, hit, len, status;
@@ -357,6 +376,23 @@ static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 		push_arg("-e");
 		push_arg(p->pattern);
 	}
+	if (opt->color) {
+		struct strbuf sb = STRBUF_INIT;
+
+		grep_add_color(&sb, opt->color_match);
+		setenv("GREP_COLOR", sb.buf, 1);
+
+		strbuf_reset(&sb);
+		strbuf_addstr(&sb, "mt=");
+		grep_add_color(&sb, opt->color_match);
+		strbuf_addstr(&sb, ":sl=:cx=:fn=:ln=:bn=:se=");
+		setenv("GREP_COLORS", sb.buf, 1);
+
+		strbuf_release(&sb);
+
+		if (opt->color_external && strlen(opt->color_external) > 0)
+			push_arg(opt->color_external);
+	}
 
 	hit = 0;
 	argc = nr;
diff --git a/grep.h b/grep.h
index 73b33ab..a67005d 100644
--- a/grep.h
+++ b/grep.h
@@ -80,6 +80,7 @@ struct grep_opt {
 	unsigned null_following_name:1;
 	int color;
 	char color_match[COLOR_MAXLEN];
+	const char *color_external;
 	int regflags;
 	unsigned pre_context;
 	unsigned post_context;
-- 
1.6.2
Previous: René ScharfeNext: Nguyen Thai Ngoc Duy
Message 6 of 10 in “grep: color search patterns”
  1. 0/5 grep: color search patternsRené Scharfe, Mar 7, 2009
  2. 1/5 grep: micro-optimize hit collection for AND nodesRené Scharfe, Mar 7, 2009
  3. 2/5 grep: remove grep_opt argument from match_expr_eval()René Scharfe, Mar 7, 2009
  4. 3/5 grep: add pmatch and eflags arguments to match_one_pattern()René Scharfe, Mar 7, 2009
  5. 4/5 grep: color patterns in outputRené Scharfe, Mar 7, 2009
  6. 5/5 grep: add support for coloring with external grepsRené Scharfe, Mar 7, 2009
  7. Nguyen Thai Ngoc DuyMar 10, 2009
  8. René ScharfeMar 10, 2009
  9. grep: prefer builtin over external one when coloring resultspclouds@gmail.com, Mar 16, 2009
  10. René ScharfeMar 16, 2009

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