grep: add a grep.patternType configuration setting

The grep.extendedRegexp configuration setting enables the -E flag on grep
by default but there are no equivalents for the -G, -F and -P flags.

Rather than adding an additional setting for grep.fooRegexp for current
and future pattern matching options, add a grep.patternType setting that
can accept appropriate values for modifying the default grep pattern
matching behavior. The current values are "basic", "extended", "fixed",
"perl" and "default" for setting -G, -E, -F, -P and the default behavior
respectively.

When grep.patternType is set to a value other than "default", the
grep.extendedRegexp setting is ignored. The value of "default" restores
the current default behavior, including the grep.extendedRegexp
behavior.

Signed-off-by: J Smith <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dark-panda

Documentation/config.txt

@@ -1196,8 +1196,16 @@ gitweb.snapshot::
 grep.lineNumber::
 	If set to true, enable '-n' option by default.
 
+grep.patternType::
+	Set the default matching behavior. Using a value of 'basic', 'extended',
+	'fixed', or 'perl' will enable the '--basic-regexp', '--extended-regexp',
+	'--fixed-strings', or '--perl-regexp' option accordingly, while the
+	value 'default' will return to the default matching behavior.
+
 grep.extendedRegexp::
-	If set to true, enable '--extended-regexp' option by default.
+	If set to true, enable '--extended-regexp' option by default. This
+	option is ignored when the 'grep.patternType' option is set to a value
+	other than 'default'.
 
 gpg.program::
 	Use this custom program instead of "gpg" found on $PATH when

Documentation/git-grep.txt

@@ -42,8 +42,16 @@ CONFIGURATION
 grep.lineNumber::
 	If set to true, enable '-n' option by default.
 
+grep.patternType::
+	Set the default matching behavior. Using a value of 'basic', 'extended',
+	'fixed', or 'perl' will enable the '--basic-regexp', '--extended-regexp',
+	'--fixed-strings', or '--perl-regexp' option accordingly, while the
+	value 'default' will return to the default matching behavior.
+
 grep.extendedRegexp::
-	If set to true, enable '--extended-regexp' option by default.
+	If set to true, enable '--extended-regexp' option by default. This
+	option is ignored when the 'grep.patternType' option is set to a value
+	other than 'default'.
 
 
 OPTIONS

builtin/grep.c

@@ -260,6 +260,53 @@ static int wait_all(void)
 }
 #endif
 
+static int parse_pattern_type_arg(const char *opt, const char *arg)
+{
+	if (!strcmp(arg, "default"))
+		return GREP_PATTERN_TYPE_UNSPECIFIED;
+	else if (!strcmp(arg, "basic"))
+		return GREP_PATTERN_TYPE_BRE;
+	else if (!strcmp(arg, "extended"))
+		return GREP_PATTERN_TYPE_ERE;
+	else if (!strcmp(arg, "fixed"))
+		return GREP_PATTERN_TYPE_FIXED;
+	else if (!strcmp(arg, "perl"))
+		return GREP_PATTERN_TYPE_PCRE;
+	die("bad %s argument: %s", opt, arg);
+}
+
+static void grep_pattern_type_options(const int pattern_type, struct grep_opt *opt)
+{
+	switch (pattern_type) {
+	case GREP_PATTERN_TYPE_UNSPECIFIED:
+		/* fall through */
+
+	case GREP_PATTERN_TYPE_BRE:
+		opt->fixed = 0;
+		opt->pcre = 0;
+		opt->regflags &= ~REG_EXTENDED;
+		break;
+
+	case GREP_PATTERN_TYPE_ERE:
+		opt->fixed = 0;
+		opt->pcre = 0;
+		opt->regflags |= REG_EXTENDED;
+		break;
+
+	case GREP_PATTERN_TYPE_FIXED:
+		opt->fixed = 1;
+		opt->pcre = 0;
+		opt->regflags &= ~REG_EXTENDED;
+		break;
+
+	case GREP_PATTERN_TYPE_PCRE:
+		opt->fixed = 0;
+		opt->pcre = 1;
+		opt->regflags &= ~REG_EXTENDED;
+		break;
+	}
+}
+
 static int grep_config(const char *var, const char *value, void *cb)
 {
 	struct grep_opt *opt = cb;
@@ -270,12 +317,17 @@ static int grep_config(const char *var, const char *value, void *cb)
 
 	if (!strcmp(var, "grep.extendedregexp")) {
 		if (git_config_bool(var, value))
-			opt->regflags |= REG_EXTENDED;
+			opt->extended_regexp_option = 1;
 		else
-			opt->regflags &= ~REG_EXTENDED;
+			opt->extended_regexp_option = 0;
 		return 0;
 	}
 
+	if (!strcmp(var, "grep.patterntype")) {
+		opt->pattern_type_option = parse_pattern_type_arg(var, value);
+		return 0;
+  }
+
 	if (!strcmp(var, "grep.linenumber")) {
 		opt->linenum = git_config_bool(var, value);
 		return 0;
@@ -669,14 +721,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	int i;
 	int dummy;
 	int use_index = 1;
-	enum {
-		pattern_type_unspecified = 0,
-		pattern_type_bre,
-		pattern_type_ere,
-		pattern_type_fixed,
-		pattern_type_pcre,
-	};
-	int pattern_type = pattern_type_unspecified;
+	int pattern_type_arg = GREP_PATTERN_TYPE_UNSPECIFIED;
 
 	struct option options[] = {
 		OPT_BOOLEAN(0, "cached", &cached,
@@ -703,18 +748,18 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			"descend at most <depth> levels", PARSE_OPT_NONEG,
 			NULL, 1 },
 		OPT_GROUP(""),
-		OPT_SET_INT('E', "extended-regexp", &pattern_type,
+		OPT_SET_INT('E', "extended-regexp", &pattern_type_arg,
 			    "use extended POSIX regular expressions",
-			    pattern_type_ere),
-		OPT_SET_INT('G', "basic-regexp", &pattern_type,
+			    GREP_PATTERN_TYPE_ERE),
+		OPT_SET_INT('G', "basic-regexp", &pattern_type_arg,
 			    "use basic POSIX regular expressions (default)",
-			    pattern_type_bre),
-		OPT_SET_INT('F', "fixed-strings", &pattern_type,
+			    GREP_PATTERN_TYPE_BRE),
+		OPT_SET_INT('F', "fixed-strings", &pattern_type_arg,
 			    "interpret patterns as fixed strings",
-			    pattern_type_fixed),
-		OPT_SET_INT('P', "perl-regexp", &pattern_type,
+			    GREP_PATTERN_TYPE_FIXED),
+		OPT_SET_INT('P', "perl-regexp", &pattern_type_arg,
 			    "use Perl-compatible regular expressions",
-			    pattern_type_pcre),
+			    GREP_PATTERN_TYPE_PCRE),
 		OPT_GROUP(""),
 		OPT_BOOLEAN('n', "line-number", &opt.linenum, "show line numbers"),
 		OPT_NEGBIT('h', NULL, &opt.pathname, "don't show filenames", 1),
@@ -799,6 +844,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	opt.header_tail = &opt.header_list;
 	opt.regflags = REG_NEWLINE;
 	opt.max_depth = -1;
+	opt.pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED;
+	opt.extended_regexp_option = 0;
 
 	strcpy(opt.color_context, "");
 	strcpy(opt.color_filename, "");
@@ -824,28 +871,13 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			     PARSE_OPT_KEEP_DASHDASH |
 			     PARSE_OPT_STOP_AT_NON_OPTION |
 			     PARSE_OPT_NO_INTERNAL_HELP);
-	switch (pattern_type) {
-	case pattern_type_fixed:
-		opt.fixed = 1;
-		opt.pcre = 0;
-		break;
-	case pattern_type_bre:
-		opt.fixed = 0;
-		opt.pcre = 0;
-		opt.regflags &= ~REG_EXTENDED;
-		break;
-	case pattern_type_ere:
-		opt.fixed = 0;
-		opt.pcre = 0;
-		opt.regflags |= REG_EXTENDED;
-		break;
-	case pattern_type_pcre:
-		opt.fixed = 0;
-		opt.pcre = 1;
-		break;
-	default:
-		break; /* nothing */
-	}
+
+	if (pattern_type_arg != GREP_PATTERN_TYPE_UNSPECIFIED)
+		grep_pattern_type_options(pattern_type_arg, &opt);
+	else if (opt.pattern_type_option != GREP_PATTERN_TYPE_UNSPECIFIED)
+		grep_pattern_type_options(opt.pattern_type_option, &opt);
+	else if (opt.extended_regexp_option)
+		grep_pattern_type_options(GREP_PATTERN_TYPE_ERE, &opt);
 
 	if (use_index && !startup_info->have_repository)
 		/* die the same way as if we did it at the beginning */

grep.h

@@ -58,6 +58,14 @@ enum grep_expr_node {
 	GREP_NODE_OR
 };
 
+enum grep_pattern_type {
+	GREP_PATTERN_TYPE_UNSPECIFIED = 0,
+	GREP_PATTERN_TYPE_BRE,
+	GREP_PATTERN_TYPE_ERE,
+	GREP_PATTERN_TYPE_FIXED,
+	GREP_PATTERN_TYPE_PCRE
+};
+
 struct grep_expr {
 	enum grep_expr_node node;
 	unsigned hit;
@@ -103,6 +111,8 @@ struct grep_opt {
 	int max_depth;
 	int funcname;
 	int funcbody;
+	int extended_regexp_option;
+	int pattern_type_option;
 	char color_context[COLOR_MAXLEN];
 	char color_filename[COLOR_MAXLEN];
 	char color_function[COLOR_MAXLEN];