builtin-tag.c - jrn/git - Git at Google

 /*
  * Builtin "git tag"
  *
  * Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>,
  *                    Carlos Rica <jasampler@gmail.com>
  * Based on git-tag.sh and mktag.c by Linus Torvalds.
  */

 #include "cache.h"
 #include "builtin.h"
 #include "refs.h"
 #include "tag.h"
 #include "run-command.h"
 #include "parse-options.h"

 static const char * const git_tag_usage[] = {
 	"git-tag [-a|-s|-u <key-id>] [-f] [-m <msg>|-F <file>] <tagname> [<head>]",
 	"git-tag -d <tagname>...",
 	"git-tag -l [-n[<num>]] [<pattern>]",
 	"git-tag -v <tagname>...",
 	NULL
 };

 static char signingkey[1000];

 void launch_editor(const char *path, struct strbuf *buffer, const char *const *env)
 {
 	const char *editor, *terminal;

 	editor = getenv("GIT_EDITOR");
 	if (!editor && editor_program)
 		editor = editor_program;
 	if (!editor)
 		editor = getenv("VISUAL");
 	if (!editor)
 		editor = getenv("EDITOR");

 	terminal = getenv("TERM");
 	if (!editor && (!terminal || !strcmp(terminal, "dumb"))) {
 		fprintf(stderr,
 		"Terminal is dumb but no VISUAL nor EDITOR defined.\n"
 		"Please supply the message using either -m or -F option.\n");
 		exit(1);
 	}

 	if (!editor)
 		editor = "vi";

 	if (strcmp(editor, ":")) {
 		size_t len = strlen(editor);
 		int i = 0;
 		const char *args[6];
 		struct strbuf arg0;

 		strbuf_init(&arg0, 0);
 		if (strcspn(editor, "$ \t'") != len) {
 			/* there are specials */
 			strbuf_addf(&arg0, "%s \"$@\"", editor);
 			args[i++] = "sh";
 			args[i++] = "-c";
 			args[i++] = arg0.buf;
 		}
 		args[i++] = editor;
 		args[i++] = path;
 		args[i] = NULL;

 		if (run_command_v_opt_cd_env(args, 0, NULL, env))
 			die("There was a problem with the editor %s.", editor);
 		strbuf_release(&arg0);
 	}

 	if (!buffer)
 		return;
 	if (strbuf_read_file(buffer, path, 0) < 0)
 		die("could not read message file '%s': %s",
 		    path, strerror(errno));
 }

 struct tag_filter {
 	const char *pattern;
 	int lines;
 };

 #define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"

 static int show_reference(const char *refname, const unsigned char *sha1,
 			  int flag, void *cb_data)
 {
 	struct tag_filter *filter = cb_data;

 	if (!fnmatch(filter->pattern, refname, 0)) {
 		int i;
 		unsigned long size;
 		enum object_type type;
 		char *buf, *sp, *eol;
 		size_t len;

 		if (!filter->lines) {
 			printf("%s\n", refname);
 			return 0;
 		}
 		printf("%-15s ", refname);

 		buf = read_sha1_file(sha1, &type, &size);
 		if (!buf || !size)
 			return 0;

 		/* skip header */
 		sp = strstr(buf, "\n\n");
 		if (!sp) {
 			free(buf);
 			return 0;
 		}
 		/* only take up to "lines" lines, and strip the signature */
 		for (i = 0, sp += 2;
 				i < filter->lines && sp < buf + size &&
 				prefixcmp(sp, PGP_SIGNATURE "\n");
 				i++) {
 			if (i)
 				printf("\n    ");
 			eol = memchr(sp, '\n', size - (sp - buf));
 			len = eol ? eol - sp : size - (sp - buf);
 			fwrite(sp, len, 1, stdout);
 			if (!eol)
 				break;
 			sp = eol + 1;
 		}
 		putchar('\n');
 		free(buf);
 	}

 	return 0;
 }

 static int list_tags(const char *pattern, int lines)
 {
 	struct tag_filter filter;

 	if (pattern == NULL)
 		pattern = "*";

 	filter.pattern = pattern;
 	filter.lines = lines;

 	for_each_tag_ref(show_reference, (void *) &filter);

 	return 0;
 }

 typedef int (*each_tag_name_fn)(const char *name, const char *ref,
 				const unsigned char *sha1);

 static int for_each_tag_name(const char **argv, each_tag_name_fn fn)
 {
 	const char **p;
 	char ref[PATH_MAX];
 	int had_error = 0;
 	unsigned char sha1[20];

 	for (p = argv; *p; p++) {
 		if (snprintf(ref, sizeof(ref), "refs/tags/%s", *p)
 					>= sizeof(ref)) {
 			error("tag name too long: %.*s...", 50, *p);
 			had_error = 1;
 			continue;
 		}
 		if (!resolve_ref(ref, sha1, 1, NULL)) {
 			error("tag '%s' not found.", *p);
 			had_error = 1;
 			continue;
 		}
 		if (fn(*p, ref, sha1))
 			had_error = 1;
 	}
 	return had_error;
 }

 static int delete_tag(const char *name, const char *ref,
 				const unsigned char *sha1)
 {
 	if (delete_ref(ref, sha1))
 		return 1;
 	printf("Deleted tag '%s'\n", name);
 	return 0;
 }

 static int verify_tag(const char *name, const char *ref,
 				const unsigned char *sha1)
 {
 	const char *argv_verify_tag[] = {"git-verify-tag",
 					"-v", "SHA1_HEX", NULL};
 	argv_verify_tag[2] = sha1_to_hex(sha1);

 	if (run_command_v_opt(argv_verify_tag, 0))
 		return error("could not verify the tag '%s'", name);
 	return 0;
 }

 static int do_sign(struct strbuf *buffer)
 {
 	struct child_process gpg;
 	const char *args[4];
 	char *bracket;
 	int len;

 	if (!*signingkey) {
 		if (strlcpy(signingkey, git_committer_info(IDENT_ERROR_ON_NO_NAME),
 				sizeof(signingkey)) > sizeof(signingkey) - 1)
 			return error("committer info too long.");
 		bracket = strchr(signingkey, '>');
 		if (bracket)
 			bracket[1] = '\0';
 	}

 	/* When the username signingkey is bad, program could be terminated
 	 * because gpg exits without reading and then write gets SIGPIPE. */
 	signal(SIGPIPE, SIG_IGN);

 	memset(&gpg, 0, sizeof(gpg));
 	gpg.argv = args;
 	gpg.in = -1;
 	gpg.out = -1;
 	args[0] = "gpg";
 	args[1] = "-bsau";
 	args[2] = signingkey;
 	args[3] = NULL;

 	if (start_command(&gpg))
 		return error("could not run gpg.");

 	if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
 		close(gpg.in);
 		close(gpg.out);
 		finish_command(&gpg);
 		return error("gpg did not accept the tag data");
 	}
 	close(gpg.in);
 	len = strbuf_read(buffer, gpg.out, 1024);
 	close(gpg.out);

 	if (finish_command(&gpg) || !len || len < 0)
 		return error("gpg failed to sign the tag");

 	return 0;
 }

 static const char tag_template[] =
 	"\n"
 	"#\n"
 	"# Write a tag message\n"
 	"#\n";

 static void set_signingkey(const char *value)
 {
 	if (strlcpy(signingkey, value, sizeof(signingkey)) >= sizeof(signingkey))
 		die("signing key value too long (%.10s...)", value);
 }

 static int git_tag_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "user.signingkey")) {
 		if (!value)
 			return config_error_nonbool(value);
 		set_signingkey(value);
 		return 0;
 	}

 	return git_default_config(var, value, cb);
 }

 static void write_tag_body(int fd, const unsigned char *sha1)
 {
 	unsigned long size;
 	enum object_type type;
 	char *buf, *sp, *eob;
 	size_t len;

 	buf = read_sha1_file(sha1, &type, &size);
 	if (!buf)
 		return;
 	/* skip header */
 	sp = strstr(buf, "\n\n");

 	if (!sp || !size || type != OBJ_TAG) {
 		free(buf);
 		return;
 	}
 	sp += 2; /* skip the 2 LFs */
 	eob = strstr(sp, "\n" PGP_SIGNATURE "\n");
 	if (eob)
 		len = eob - sp;
 	else
 		len = buf + size - sp;
 	write_or_die(fd, sp, len);

 	free(buf);
 }

 static void create_tag(const unsigned char *object, const char *tag,
 		       struct strbuf *buf, int message, int sign,
 		       unsigned char *prev, unsigned char *result)
 {
 	enum object_type type;
 	char header_buf[1024];
 	int header_len;

 	type = sha1_object_info(object, NULL);
 	if (type <= OBJ_NONE)
 	    die("bad object type.");

 	header_len = snprintf(header_buf, sizeof(header_buf),
 			  "object %s\n"
 			  "type %s\n"
 			  "tag %s\n"
 			  "tagger %s\n\n",
 			  sha1_to_hex(object),
 			  typename(type),
 			  tag,
 			  git_committer_info(IDENT_ERROR_ON_NO_NAME));

 	if (header_len > sizeof(header_buf) - 1)
 		die("tag header too big.");

 	if (!message) {
 		char *path;
 		int fd;

 		/* write the template message before editing: */
 		path = xstrdup(git_path("TAG_EDITMSG"));
 		fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 		if (fd < 0)
 			die("could not create file '%s': %s",
 						path, strerror(errno));

 		if (!is_null_sha1(prev))
 			write_tag_body(fd, prev);
 		else
 			write_or_die(fd, tag_template, strlen(tag_template));
 		close(fd);

 		launch_editor(path, buf, NULL);

 		unlink(path);
 		free(path);
 	}

 	stripspace(buf, 1);

 	if (!message && !buf->len)
 		die("no tag message?");

 	strbuf_insert(buf, 0, header_buf, header_len);

 	if (sign && do_sign(buf) < 0)
 		die("unable to sign the tag");
 	if (write_sha1_file(buf->buf, buf->len, tag_type, result) < 0)
 		die("unable to write tag file");
 }

 struct msg_arg {
 	int given;
 	struct strbuf buf;
 };

 static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
 {
 	struct msg_arg *msg = opt->value;

 	if (!arg)
 		return -1;
 	if (msg->buf.len)
 		strbuf_addstr(&(msg->buf), "\n\n");
 	strbuf_addstr(&(msg->buf), arg);
 	msg->given = 1;
 	return 0;
 }

 int cmd_tag(int argc, const char **argv, const char *prefix)
 {
 	struct strbuf buf;
 	unsigned char object[20], prev[20];
 	char ref[PATH_MAX];
 	const char *object_ref, *tag;
 	struct ref_lock *lock;

 	int annotate = 0, sign = 0, force = 0, lines = 0,
 		list = 0, delete = 0, verify = 0;
 	char *msgfile = NULL, *keyid = NULL;
 	struct msg_arg msg = { 0, STRBUF_INIT };
 	struct option options[] = {
 		OPT_BOOLEAN('l', NULL, &list, "list tag names"),
 		{ OPTION_INTEGER, 'n', NULL, &lines, NULL,
 				"print n lines of each tag message",
 				PARSE_OPT_OPTARG, NULL, 1 },
 		OPT_BOOLEAN('d', NULL, &delete, "delete tags"),
 		OPT_BOOLEAN('v', NULL, &verify, "verify tags"),

 		OPT_GROUP("Tag creation options"),
 		OPT_BOOLEAN('a', NULL, &annotate,
 					"annotated tag, needs a message"),
 		OPT_CALLBACK('m', NULL, &msg, "msg",
 			     "message for the tag", parse_msg_arg),
 		OPT_STRING('F', NULL, &msgfile, "file", "message in a file"),
 		OPT_BOOLEAN('s', NULL, &sign, "annotated and GPG-signed tag"),
 		OPT_STRING('u', NULL, &keyid, "key-id",
 					"use another key to sign the tag"),
 		OPT_BOOLEAN('f', NULL, &force, "replace the tag if exists"),
 		OPT_END()
 	};

 	git_config(git_tag_config, NULL);

 	argc = parse_options(argc, argv, options, git_tag_usage, 0);

 	if (keyid) {
 		sign = 1;
 		set_signingkey(keyid);
 	}
 	if (sign)
 		annotate = 1;

 	if (list)
 		return list_tags(argv[0], lines);
 	if (delete)
 		return for_each_tag_name(argv, delete_tag);
 	if (verify)
 		return for_each_tag_name(argv, verify_tag);

 	strbuf_init(&buf, 0);
 	if (msg.given || msgfile) {
 		if (msg.given && msgfile)
 			die("only one -F or -m option is allowed.");
 		annotate = 1;
 		if (msg.given)
 			strbuf_addbuf(&buf, &(msg.buf));
 		else {
 			if (!strcmp(msgfile, "-")) {
 				if (strbuf_read(&buf, 0, 1024) < 0)
 					die("cannot read %s", msgfile);
 			} else {
 				if (strbuf_read_file(&buf, msgfile, 1024) < 0)
 					die("could not open or read '%s': %s",
 						msgfile, strerror(errno));
 			}
 		}
 	}

 	if (argc == 0) {
 		if (annotate)
 			usage_with_options(git_tag_usage, options);
 		return list_tags(NULL, lines);
 	}
 	tag = argv[0];

 	object_ref = argc == 2 ? argv[1] : "HEAD";
 	if (argc > 2)
 		die("too many params");

 	if (get_sha1(object_ref, object))
 		die("Failed to resolve '%s' as a valid ref.", object_ref);

 	if (snprintf(ref, sizeof(ref), "refs/tags/%s", tag) > sizeof(ref) - 1)
 		die("tag name too long: %.*s...", 50, tag);
 	if (check_ref_format(ref))
 		die("'%s' is not a valid tag name.", tag);

 	if (!resolve_ref(ref, prev, 1, NULL))
 		hashclr(prev);
 	else if (!force)
 		die("tag '%s' already exists", tag);

 	if (annotate)
 		create_tag(object, tag, &buf, msg.given || msgfile,
 			   sign, prev, object);

 	lock = lock_any_ref_for_update(ref, prev, 0);
 	if (!lock)
 		die("%s: cannot lock the ref", ref);
 	if (write_ref_sha1(lock, object, NULL) < 0)
 		die("%s: cannot update the ref", ref);

 	strbuf_release(&buf);
 	return 0;
 }
	/*
	* Builtin "git tag"
	*
	* Copyright (c) 2007 Kristian Høgsberg <krh@redhat.com>,
	* Carlos Rica <jasampler@gmail.com>
	* Based on git-tag.sh and mktag.c by Linus Torvalds.
	*/

	#include "cache.h"
	#include "builtin.h"
	#include "refs.h"
	#include "tag.h"
	#include "run-command.h"
	#include "parse-options.h"

	static const char * const git_tag_usage[] = {
	"git-tag [-a\|-s\|-u <key-id>] [-f] [-m <msg>\|-F <file>] <tagname> [<head>]",
	"git-tag -d <tagname>...",
	"git-tag -l [-n[<num>]] [<pattern>]",
	"git-tag -v <tagname>...",
	NULL
	};

	static char signingkey[1000];

	void launch_editor(const char path, struct strbuf buffer, const char const env)
	{
	const char editor, terminal;

	editor = getenv("GIT_EDITOR");
	if (!editor && editor_program)
	editor = editor_program;
	if (!editor)
	editor = getenv("VISUAL");
	if (!editor)
	editor = getenv("EDITOR");

	terminal = getenv("TERM");
	if (!editor && (!terminal \|\| !strcmp(terminal, "dumb"))) {
	fprintf(stderr,
	"Terminal is dumb but no VISUAL nor EDITOR defined.\n"
	"Please supply the message using either -m or -F option.\n");
	exit(1);
	}

	if (!editor)
	editor = "vi";

	if (strcmp(editor, ":")) {
	size_t len = strlen(editor);
	int i = 0;
	const char *args[6];
	struct strbuf arg0;

	strbuf_init(&arg0, 0);
	if (strcspn(editor, "$ \t'") != len) {
	/* there are specials */
	strbuf_addf(&arg0, "%s \"$@\"", editor);
	args[i++] = "sh";
	args[i++] = "-c";
	args[i++] = arg0.buf;
	}
	args[i++] = editor;
	args[i++] = path;
	args[i] = NULL;

	if (run_command_v_opt_cd_env(args, 0, NULL, env))
	die("There was a problem with the editor %s.", editor);
	strbuf_release(&arg0);
	}

	if (!buffer)
	return;
	if (strbuf_read_file(buffer, path, 0) < 0)
	die("could not read message file '%s': %s",
	path, strerror(errno));
	}

	struct tag_filter {
	const char *pattern;
	int lines;
	};

	#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"

	static int show_reference(const char refname, const unsigned char sha1,
	int flag, void *cb_data)
	{
	struct tag_filter *filter = cb_data;

	if (!fnmatch(filter->pattern, refname, 0)) {
	int i;
	unsigned long size;
	enum object_type type;
	char buf, sp, *eol;
	size_t len;

	if (!filter->lines) {
	printf("%s\n", refname);
	return 0;
	}
	printf("%-15s ", refname);

	buf = read_sha1_file(sha1, &type, &size);
	if (!buf \|\| !size)
	return 0;

	/* skip header */
	sp = strstr(buf, "\n\n");
	if (!sp) {
	free(buf);
	return 0;
	}
	/* only take up to "lines" lines, and strip the signature */
	for (i = 0, sp += 2;
	i < filter->lines && sp < buf + size &&
	prefixcmp(sp, PGP_SIGNATURE "\n");
	i++) {
	if (i)
	printf("\n ");
	eol = memchr(sp, '\n', size - (sp - buf));
	len = eol ? eol - sp : size - (sp - buf);
	fwrite(sp, len, 1, stdout);
	if (!eol)
	break;
	sp = eol + 1;
	}
	putchar('\n');
	free(buf);
	}

	return 0;
	}

	static int list_tags(const char *pattern, int lines)
	{
	struct tag_filter filter;

	if (pattern == NULL)
	pattern = "*";

	filter.pattern = pattern;
	filter.lines = lines;

	for_each_tag_ref(show_reference, (void *) &filter);

	return 0;
	}

	typedef int (each_tag_name_fn)(const char name, const char *ref,
	const unsigned char *sha1);

	static int for_each_tag_name(const char **argv, each_tag_name_fn fn)
	{
	const char **p;
	char ref[PATH_MAX];
	int had_error = 0;
	unsigned char sha1[20];

	for (p = argv; *p; p++) {
	if (snprintf(ref, sizeof(ref), "refs/tags/%s", *p)
	>= sizeof(ref)) {
	error("tag name too long: %.s...", 50, p);
	had_error = 1;
	continue;
	}
	if (!resolve_ref(ref, sha1, 1, NULL)) {
	error("tag '%s' not found.", *p);
	had_error = 1;
	continue;
	}
	if (fn(*p, ref, sha1))
	had_error = 1;
	}
	return had_error;
	}

	static int delete_tag(const char name, const char ref,
	const unsigned char *sha1)
	{
	if (delete_ref(ref, sha1))
	return 1;
	printf("Deleted tag '%s'\n", name);
	return 0;
	}

	static int verify_tag(const char name, const char ref,
	const unsigned char *sha1)
	{
	const char *argv_verify_tag[] = {"git-verify-tag",
	"-v", "SHA1_HEX", NULL};
	argv_verify_tag[2] = sha1_to_hex(sha1);

	if (run_command_v_opt(argv_verify_tag, 0))
	return error("could not verify the tag '%s'", name);
	return 0;
	}

	static int do_sign(struct strbuf *buffer)
	{
	struct child_process gpg;
	const char *args[4];
	char *bracket;
	int len;

	if (!*signingkey) {
	if (strlcpy(signingkey, git_committer_info(IDENT_ERROR_ON_NO_NAME),
	sizeof(signingkey)) > sizeof(signingkey) - 1)
	return error("committer info too long.");
	bracket = strchr(signingkey, '>');
	if (bracket)
	bracket[1] = '\0';
	}

	/* When the username signingkey is bad, program could be terminated
	* because gpg exits without reading and then write gets SIGPIPE. */
	signal(SIGPIPE, SIG_IGN);

	memset(&gpg, 0, sizeof(gpg));
	gpg.argv = args;
	gpg.in = -1;
	gpg.out = -1;
	args[0] = "gpg";
	args[1] = "-bsau";
	args[2] = signingkey;
	args[3] = NULL;

	if (start_command(&gpg))
	return error("could not run gpg.");

	if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
	close(gpg.in);
	close(gpg.out);
	finish_command(&gpg);
	return error("gpg did not accept the tag data");
	}
	close(gpg.in);
	len = strbuf_read(buffer, gpg.out, 1024);
	close(gpg.out);

	if (finish_command(&gpg) \|\| !len \|\| len < 0)
	return error("gpg failed to sign the tag");

	return 0;
	}

	static const char tag_template[] =
	"\n"
	"#\n"
	"# Write a tag message\n"
	"#\n";

	static void set_signingkey(const char *value)
	{
	if (strlcpy(signingkey, value, sizeof(signingkey)) >= sizeof(signingkey))
	die("signing key value too long (%.10s...)", value);
	}

	static int git_tag_config(const char var, const char value, void *cb)
	{
	if (!strcmp(var, "user.signingkey")) {
	if (!value)
	return config_error_nonbool(value);
	set_signingkey(value);
	return 0;
	}

	return git_default_config(var, value, cb);
	}

	static void write_tag_body(int fd, const unsigned char *sha1)
	{
	unsigned long size;
	enum object_type type;
	char buf, sp, *eob;
	size_t len;

	buf = read_sha1_file(sha1, &type, &size);
	if (!buf)
	return;
	/* skip header */
	sp = strstr(buf, "\n\n");

	if (!sp \|\| !size \|\| type != OBJ_TAG) {
	free(buf);
	return;
	}
	sp += 2; /* skip the 2 LFs */
	eob = strstr(sp, "\n" PGP_SIGNATURE "\n");
	if (eob)
	len = eob - sp;
	else
	len = buf + size - sp;
	write_or_die(fd, sp, len);

	free(buf);
	}

	static void create_tag(const unsigned char object, const char tag,
	struct strbuf *buf, int message, int sign,
	unsigned char prev, unsigned char result)
	{
	enum object_type type;
	char header_buf[1024];
	int header_len;

	type = sha1_object_info(object, NULL);
	if (type <= OBJ_NONE)
	die("bad object type.");

	header_len = snprintf(header_buf, sizeof(header_buf),
	"object %s\n"
	"type %s\n"
	"tag %s\n"
	"tagger %s\n\n",
	sha1_to_hex(object),
	typename(type),
	tag,
	git_committer_info(IDENT_ERROR_ON_NO_NAME));

	if (header_len > sizeof(header_buf) - 1)
	die("tag header too big.");

	if (!message) {
	char *path;
	int fd;

	/* write the template message before editing: */
	path = xstrdup(git_path("TAG_EDITMSG"));
	fd = open(path, O_CREAT \| O_TRUNC \| O_WRONLY, 0600);
	if (fd < 0)
	die("could not create file '%s': %s",
	path, strerror(errno));

	if (!is_null_sha1(prev))
	write_tag_body(fd, prev);
	else
	write_or_die(fd, tag_template, strlen(tag_template));
	close(fd);

	launch_editor(path, buf, NULL);

	unlink(path);
	free(path);
	}

	stripspace(buf, 1);

	if (!message && !buf->len)
	die("no tag message?");

	strbuf_insert(buf, 0, header_buf, header_len);

	if (sign && do_sign(buf) < 0)
	die("unable to sign the tag");
	if (write_sha1_file(buf->buf, buf->len, tag_type, result) < 0)
	die("unable to write tag file");
	}

	struct msg_arg {
	int given;
	struct strbuf buf;
	};

	static int parse_msg_arg(const struct option opt, const char arg, int unset)
	{
	struct msg_arg *msg = opt->value;

	if (!arg)
	return -1;
	if (msg->buf.len)
	strbuf_addstr(&(msg->buf), "\n\n");
	strbuf_addstr(&(msg->buf), arg);
	msg->given = 1;
	return 0;
	}

	int cmd_tag(int argc, const char *argv, const char prefix)
	{
	struct strbuf buf;
	unsigned char object[20], prev[20];
	char ref[PATH_MAX];
	const char object_ref, tag;
	struct ref_lock *lock;

	int annotate = 0, sign = 0, force = 0, lines = 0,
	list = 0, delete = 0, verify = 0;
	char msgfile = NULL, keyid = NULL;
	struct msg_arg msg = { 0, STRBUF_INIT };
	struct option options[] = {
	OPT_BOOLEAN('l', NULL, &list, "list tag names"),
	{ OPTION_INTEGER, 'n', NULL, &lines, NULL,
	"print n lines of each tag message",
	PARSE_OPT_OPTARG, NULL, 1 },
	OPT_BOOLEAN('d', NULL, &delete, "delete tags"),
	OPT_BOOLEAN('v', NULL, &verify, "verify tags"),

	OPT_GROUP("Tag creation options"),
	OPT_BOOLEAN('a', NULL, &annotate,
	"annotated tag, needs a message"),
	OPT_CALLBACK('m', NULL, &msg, "msg",
	"message for the tag", parse_msg_arg),
	OPT_STRING('F', NULL, &msgfile, "file", "message in a file"),
	OPT_BOOLEAN('s', NULL, &sign, "annotated and GPG-signed tag"),
	OPT_STRING('u', NULL, &keyid, "key-id",
	"use another key to sign the tag"),
	OPT_BOOLEAN('f', NULL, &force, "replace the tag if exists"),
	OPT_END()
	};

	git_config(git_tag_config, NULL);

	argc = parse_options(argc, argv, options, git_tag_usage, 0);

	if (keyid) {
	sign = 1;
	set_signingkey(keyid);
	}
	if (sign)
	annotate = 1;

	if (list)
	return list_tags(argv[0], lines);
	if (delete)
	return for_each_tag_name(argv, delete_tag);
	if (verify)
	return for_each_tag_name(argv, verify_tag);

	strbuf_init(&buf, 0);
	if (msg.given \|\| msgfile) {
	if (msg.given && msgfile)
	die("only one -F or -m option is allowed.");
	annotate = 1;
	if (msg.given)
	strbuf_addbuf(&buf, &(msg.buf));
	else {
	if (!strcmp(msgfile, "-")) {
	if (strbuf_read(&buf, 0, 1024) < 0)
	die("cannot read %s", msgfile);
	} else {
	if (strbuf_read_file(&buf, msgfile, 1024) < 0)
	die("could not open or read '%s': %s",
	msgfile, strerror(errno));
	}
	}
	}

	if (argc == 0) {
	if (annotate)
	usage_with_options(git_tag_usage, options);
	return list_tags(NULL, lines);
	}
	tag = argv[0];

	object_ref = argc == 2 ? argv[1] : "HEAD";
	if (argc > 2)
	die("too many params");

	if (get_sha1(object_ref, object))
	die("Failed to resolve '%s' as a valid ref.", object_ref);

	if (snprintf(ref, sizeof(ref), "refs/tags/%s", tag) > sizeof(ref) - 1)
	die("tag name too long: %.*s...", 50, tag);
	if (check_ref_format(ref))
	die("'%s' is not a valid tag name.", tag);

	if (!resolve_ref(ref, prev, 1, NULL))
	hashclr(prev);
	else if (!force)
	die("tag '%s' already exists", tag);

	if (annotate)
	create_tag(object, tag, &buf, msg.given \|\| msgfile,
	sign, prev, object);

	lock = lock_any_ref_for_update(ref, prev, 0);
	if (!lock)
	die("%s: cannot lock the ref", ref);
	if (write_ref_sha1(lock, object, NULL) < 0)
	die("%s: cannot update the ref", ref);

	strbuf_release(&buf);
	return 0;
	}