[PATCH] config: Add --quoted option to produce machine-parsable output

[Frank Lichtenheld <frank@lichtenheld.de>]

This option will enclose key names in quotes (") if they
contain a subsection and then escape " and \. It will also
escape line breaks in values. Together this should produce
an easily parsable output.

Affects --list and --get-*

Signed-off-by: Frank Lichtenheld <frank@lichtenheld.de>
---
 builtin-config.c |   92 ++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 83 insertions(+), 9 deletions(-)

 Will add asciidoc documentation and test cases if people think that this is
 a good idea.

 I'm writing C about once a year, so I really don't mind being told if it's
 crap ;)

diff --git a/builtin-config.c b/builtin-config.c
index b2515f7..454cf4e 100644
--- a/builtin-config.c
+++ b/builtin-config.c
@@ -2,7 +2,7 @@
 #include "cache.h"
 
 static const char git_config_set_usage[] =
-"git-config [ --global | --system ] [ --bool | --int ] [--get | --get-all | --get-regexp | --replace-all | --add | --unset | --unset-all] name [value [value_regex]] | --rename-section old_name new_name | --remove-section name | --list";
+"git-config [ --global | --system ] [ --bool | --int ] [--quoted] [--get | --get-all | --get-regexp | --replace-all | --add | --unset | --unset-all] name [value [value_regex]] | --rename-section old_name new_name | --remove-section name | --list";
 
 static char *key;
 static regex_t *key_regexp;
@@ -12,14 +12,73 @@ static int use_key_regexp;
 static int do_all;
 static int do_not_match;
 static int seen;
+static int quoted;
 static enum { T_RAW, T_INT, T_BOOL } type = T_RAW;
 
+static char* quote_key(const char *key_)
+{
+	char *pos1, *pos2;
+	char* key_quot;
+
+	pos1 = strchr(key_, '.');
+	pos2 = strrchr(key_, '.');
+	if (pos1 != pos2) { /* has subsection */
+		char* key;
+		key = xmalloc(strlen(key_)*2 + 1);
+		key_quot = key;
+		*key++ = '"';
+		while (*key_) {
+			if (*key_ == '"' || *key_ == '\\')
+				*key++ = '\\';
+			*key++ = *key_++;
+		}
+		*key++ = '"';
+		*key = 0;
+	} else {
+		key_quot = xstrdup(key_);
+	}
+	return key_quot;
+}
+
+static char* quote_value(const char* value_)
+{
+	char *val_quot, *val;
+	val = xmalloc(strlen(value_)*2 + 1);
+	val_quot = val;
+
+	while (*value_) {
+		if (*value_ == '\n') {
+			*val++ = '\\';
+			*val++ = 'n';
+			value_ += 2;
+		} else
+			*val++ = *value_++;
+	}
+	*val = 0;
+
+	return val_quot;
+}
+
 static int show_all_config(const char *key_, const char *value_)
 {
-	if (value_)
-		printf("%s=%s\n", key_, value_);
-	else
-		printf("%s\n", key_);
+	if (!quoted) {
+		if (value_)
+			printf("%s=%s\n", key_, value_);
+		else
+			printf("%s\n", key_);
+	} else {
+		char* key_quot = quote_key(key_);
+
+		if (value_) {
+			char* val_quot = quote_value(value_);
+			printf("%s=%s\n", key_quot, val_quot);
+			free(val_quot);
+		} else
+			printf("%s\n", key_quot);
+
+		free(key_quot);
+	}
+
 	return 0;
 }
 
@@ -38,16 +97,26 @@ static int show_config(const char* key_, const char* value_)
 			  regexec(regexp, (value_?value_:""), 0, NULL, 0)))
 		return 0;
 
-	if (show_keys)
-		printf("%s ", key_);
+	if (show_keys) {
+		if (quoted) {
+			char* key = quote_key(key_);
+			printf("%s ", key);
+			free(key);
+		} else
+			printf("%s ", key_);
+	}
 	if (seen && !do_all)
 		dup_error = 1;
 	if (type == T_INT)
 		sprintf(value, "%d", git_config_int(key_, value_?value_:""));
 	else if (type == T_BOOL)
 		vptr = git_config_bool(key_, value_) ? "true" : "false";
-	else
-		vptr = value_?value_:"";
+	else {
+		if (quoted)
+			vptr = value_?quote_value(value_):"";
+		else
+			vptr = value_?value_:"";
+	}
 	seen++;
 	if (dup_error) {
 		error("More than one value for the key %s: %s",
@@ -56,6 +125,9 @@ static int show_config(const char* key_, const char* value_)
 	else
 		printf("%s\n", vptr);
 
+	if (quoted && value_)
+		free((char *)vptr);
+
 	return 0;
 }
 
@@ -141,6 +213,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 			type = T_INT;
 		else if (!strcmp(argv[1], "--bool"))
 			type = T_BOOL;
+		else if (!strcmp(argv[1], "--quoted"))
+			quoted = 1;
 		else if (!strcmp(argv[1], "--list") || !strcmp(argv[1], "-l"))
 			return git_config(show_all_config);
 		else if (!strcmp(argv[1], "--global")) {
-- 
1.5.2-rc3.GIT