diff-parseopt: convert --dirstat and friends

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/diff-options.txt

@@ -148,6 +148,7 @@ These parameters can also be set individually with `--stat-width=<width>`,
 	number of modified files, as well as number of added and deleted
 	lines.
 
+-X[<param1,param2,...>]::
 --dirstat[=<param1,param2,...>]::
 	Output the distribution of relative amount of changes for each
 	sub-directory. The behavior of `--dirstat` can be customized by
@@ -192,6 +193,12 @@ directories with less than 10% of the total amount of changed files,
 and accumulating child directory counts in the parent directories:
 `--dirstat=files,10,cumulative`.
 
+--cumulative::
+	Synonym for --dirstat=cumulative
+
+--dirstat-by-file[=<param1,param2>...]::
+	Synonym for --dirstat=files,param1,param2...
+
 --summary::
 	Output a condensed summary of extended header information
 	such as creations, renames and mode changes.

diff.c

@@ -4867,6 +4867,22 @@ static int parse_objfind_opt(struct diff_options *opt, const char *arg)
 	return 1;
 }
 
+static int diff_opt_dirstat(const struct option *opt,
+			    const char *arg, int unset)
+{
+	struct diff_options *options = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+	if (!strcmp(opt->long_name, "cumulative")) {
+		if (arg)
+			BUG("how come --cumulative take a value?");
+		arg = "cumulative";
+	} else if (!strcmp(opt->long_name, "dirstat-by-file"))
+		parse_dirstat_opt(options, "files");
+	parse_dirstat_opt(options, arg ? arg : "");
+	return 0;
+}
+
 static int diff_opt_unified(const struct option *opt,
 			    const char *arg, int unset)
 {
@@ -4911,6 +4927,18 @@ static void prep_parse_options(struct diff_options *options)
 		OPT_BIT_F(0, "shortstat", &options->output_format,
 			  N_("output only the last line of --stat"),
 			  DIFF_FORMAT_SHORTSTAT, PARSE_OPT_NONEG),
+		OPT_CALLBACK_F('X', "dirstat", options, N_("<param1,param2>..."),
+			       N_("output the distribution of relative amount of changes for each sub-directory"),
+			       PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+			       diff_opt_dirstat),
+		OPT_CALLBACK_F(0, "cumulative", options, NULL,
+			       N_("synonym for --dirstat=cumulative"),
+			       PARSE_OPT_NONEG | PARSE_OPT_NOARG,
+			       diff_opt_dirstat),
+		OPT_CALLBACK_F(0, "dirstat-by-file", options, N_("<param1,param2>..."),
+			       N_("synonym for --dirstat=files,param1,param2..."),
+			       PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+			       diff_opt_dirstat),
 		OPT_END()
 	};
 
@@ -4939,16 +4967,7 @@ int diff_opt_parse(struct diff_options *options,
 		return ac;
 
 	/* Output format options */
-	if (skip_prefix(arg, "-X", &arg) ||
-		 skip_to_optional_arg(arg, "--dirstat", &arg))
-		return parse_dirstat_opt(options, arg);
-	else if (!strcmp(arg, "--cumulative"))
-		return parse_dirstat_opt(options, "cumulative");
-	else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
-		parse_dirstat_opt(options, "files");
-		return parse_dirstat_opt(options, arg);
-	}
-	else if (!strcmp(arg, "--check"))
+	if (!strcmp(arg, "--check"))
 		options->output_format |= DIFF_FORMAT_CHECKDIFF;
 	else if (!strcmp(arg, "--summary"))
 		options->output_format |= DIFF_FORMAT_SUMMARY;