builtin/multi-pack-index.c: split sub-commands

Handle sub-commands of the 'git multi-pack-index' builtin (e.g.,
"write", "repack", etc.) separately from one another. This allows
sub-commands with unique options, without forcing cmd_multi_pack_index()
to reject invalid combinations itself.

This comes at the cost of some duplication and boilerplate. Luckily, the
duplication is reduced to a minimum, since common options are shared
among sub-commands due to a suggestion by Ævar. (Sub-commands do have to
retain the common options, too, since this builtin accepts common
options on either side of the sub-command).

Roughly speaking, cmd_multi_pack_index() parses options (including
common ones), and stops at the first non-option, which is the
sub-command. It then dispatches to the appropriate sub-command, which
parses the remaining options (also including common options).

Unknown options are kept by the sub-commands in order to detect their
presence (and complain that too many arguments were given).

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/multi-pack-index.c

@@ -17,6 +17,22 @@
 #define BUILTIN_MIDX_REPACK_USAGE \
 	N_("git multi-pack-index [<options>] repack [--batch-size=<size>]")
 
+static char const * const builtin_multi_pack_index_write_usage[] = {
+	BUILTIN_MIDX_WRITE_USAGE,
+	NULL
+};
+static char const * const builtin_multi_pack_index_verify_usage[] = {
+	BUILTIN_MIDX_VERIFY_USAGE,
+	NULL
+};
+static char const * const builtin_multi_pack_index_expire_usage[] = {
+	BUILTIN_MIDX_EXPIRE_USAGE,
+	NULL
+};
+static char const * const builtin_multi_pack_index_repack_usage[] = {
+	BUILTIN_MIDX_REPACK_USAGE,
+	NULL
+};
 static char const * const builtin_multi_pack_index_usage[] = {
 	BUILTIN_MIDX_WRITE_USAGE,
 	BUILTIN_MIDX_VERIFY_USAGE,
@@ -31,25 +47,98 @@ static struct opts_multi_pack_index {
 	unsigned flags;
 } opts;
 
-int cmd_multi_pack_index(int argc, const char **argv,
-			 const char *prefix)
+static struct option common_opts[] = {
+	OPT_FILENAME(0, "object-dir", &opts.object_dir,
+	  N_("object directory containing set of packfile and pack-index pairs")),
+	OPT_BIT(0, "progress", &opts.flags, N_("force progress reporting"), MIDX_PROGRESS),
+	OPT_END(),
+};
+
+static struct option *add_common_options(struct option *prev)
 {
-	static struct option builtin_multi_pack_index_options[] = {
-		OPT_FILENAME(0, "object-dir", &opts.object_dir,
-		  N_("object directory containing set of packfile and pack-index pairs")),
-		OPT_BIT(0, "progress", &opts.flags, N_("force progress reporting"), MIDX_PROGRESS),
+	return parse_options_concat(common_opts, prev);
+}
+
+static int cmd_multi_pack_index_write(int argc, const char **argv)
+{
+	struct option *options = common_opts;
+
+	argc = parse_options(argc, argv, NULL,
+			     options, builtin_multi_pack_index_write_usage,
+			     PARSE_OPT_KEEP_UNKNOWN);
+	if (argc)
+		usage_with_options(builtin_multi_pack_index_write_usage,
+				   options);
+
+	return write_midx_file(opts.object_dir, opts.flags);
+}
+
+static int cmd_multi_pack_index_verify(int argc, const char **argv)
+{
+	struct option *options = common_opts;
+
+	argc = parse_options(argc, argv, NULL,
+			     options, builtin_multi_pack_index_verify_usage,
+			     PARSE_OPT_KEEP_UNKNOWN);
+	if (argc)
+		usage_with_options(builtin_multi_pack_index_verify_usage,
+				   options);
+
+	return verify_midx_file(the_repository, opts.object_dir, opts.flags);
+}
+
+static int cmd_multi_pack_index_expire(int argc, const char **argv)
+{
+	struct option *options = common_opts;
+
+	argc = parse_options(argc, argv, NULL,
+			     options, builtin_multi_pack_index_expire_usage,
+			     PARSE_OPT_KEEP_UNKNOWN);
+	if (argc)
+		usage_with_options(builtin_multi_pack_index_expire_usage,
+				   options);
+
+	return expire_midx_packs(the_repository, opts.object_dir, opts.flags);
+}
+
+static int cmd_multi_pack_index_repack(int argc, const char **argv)
+{
+	struct option *options;
+	static struct option builtin_multi_pack_index_repack_options[] = {
 		OPT_MAGNITUDE(0, "batch-size", &opts.batch_size,
 		  N_("during repack, collect pack-files of smaller size into a batch that is larger than this size")),
 		OPT_END(),
 	};
 
+	options = add_common_options(builtin_multi_pack_index_repack_options);
+
+	argc = parse_options(argc, argv, NULL,
+			     options,
+			     builtin_multi_pack_index_repack_usage,
+			     PARSE_OPT_KEEP_UNKNOWN);
+	if (argc)
+		usage_with_options(builtin_multi_pack_index_repack_usage,
+				   options);
+
+	FREE_AND_NULL(options);
+
+	return midx_repack(the_repository, opts.object_dir,
+			   (size_t)opts.batch_size, opts.flags);
+}
+
+int cmd_multi_pack_index(int argc, const char **argv,
+			 const char *prefix)
+{
+	struct option *builtin_multi_pack_index_options = common_opts;
+
 	git_config(git_default_config, NULL);
 
 	if (isatty(2))
 		opts.flags |= MIDX_PROGRESS;
 	argc = parse_options(argc, argv, prefix,
 			     builtin_multi_pack_index_options,
-			     builtin_multi_pack_index_usage, 0);
+			     builtin_multi_pack_index_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
 
 	if (!opts.object_dir)
 		opts.object_dir = get_object_directory();
@@ -58,25 +147,16 @@ int cmd_multi_pack_index(int argc, const char **argv,
 		usage_with_options(builtin_multi_pack_index_usage,
 				   builtin_multi_pack_index_options);
 
-	if (argc > 1) {
-		die(_("too many arguments"));
-		return 1;
-	}
-
 	trace2_cmd_mode(argv[0]);
 
 	if (!strcmp(argv[0], "repack"))
-		return midx_repack(the_repository, opts.object_dir,
-			(size_t)opts.batch_size, opts.flags);
-	if (opts.batch_size)
-		die(_("--batch-size option is only for 'repack' subcommand"));
-
-	if (!strcmp(argv[0], "write"))
-		return write_midx_file(opts.object_dir, opts.flags);
-	if (!strcmp(argv[0], "verify"))
-		return verify_midx_file(the_repository, opts.object_dir, opts.flags);
-	if (!strcmp(argv[0], "expire"))
-		return expire_midx_packs(the_repository, opts.object_dir, opts.flags);
-
-	die(_("unrecognized subcommand: %s"), argv[0]);
+		return cmd_multi_pack_index_repack(argc, argv);
+	else if (!strcmp(argv[0], "write"))
+		return cmd_multi_pack_index_write(argc, argv);
+	else if (!strcmp(argv[0], "verify"))
+		return cmd_multi_pack_index_verify(argc, argv);
+	else if (!strcmp(argv[0], "expire"))
+		return cmd_multi_pack_index_expire(argc, argv);
+	else
+		die(_("unrecognized subcommand: %s"), argv[0]);
 }