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"
 #include "diff.h"
 #include "revision.h"
 #include "gpg-interface.h"
 #include "sha1-array.h"
 #include "column.h"

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

 #define STRCMP_SORT     0	/* must be zero */
 #define VERCMP_SORT     1
 #define SORT_MASK       0x7fff
 #define REVERSE_SORT    0x8000

 static int tag_sort;

 struct tag_filter {
 	const char **patterns;
 	int lines;
 	int sort;
 	struct string_list tags;
 	struct commit_list *with_commit;
 };

 static struct sha1_array points_at;
 static unsigned int colopts;

 static int match_pattern(const char **patterns, const char *ref)
 {
 	/* no pattern means match everything */
 	if (!*patterns)
 		return 1;
 	for (; *patterns; patterns++)
 		if (!wildmatch(*patterns, ref, 0, NULL))
 			return 1;
 	return 0;
 }

 static const unsigned char *match_points_at(const char *refname,
 					    const unsigned char *sha1)
 {
 	const unsigned char *tagged_sha1 = NULL;
 	struct object *obj;

 	if (sha1_array_lookup(&points_at, sha1) >= 0)
 		return sha1;
 	obj = parse_object(sha1);
 	if (!obj)
 		die(_("malformed object at '%s'"), refname);
 	if (obj->type == OBJ_TAG)
 		tagged_sha1 = ((struct tag *)obj)->tagged->sha1;
 	if (tagged_sha1 && sha1_array_lookup(&points_at, tagged_sha1) >= 0)
 		return tagged_sha1;
 	return NULL;
 }

 static int in_commit_list(const struct commit_list *want, struct commit *c)
 {
 	for (; want; want = want->next)
 		if (!hashcmp(want->item->object.sha1, c->object.sha1))
 			return 1;
 	return 0;
 }

 enum contains_result {
 	CONTAINS_UNKNOWN = -1,
 	CONTAINS_NO = 0,
 	CONTAINS_YES = 1
 };

 /*
  * Test whether the candidate or one of its parents is contained in the list.
  * Do not recurse to find out, though, but return -1 if inconclusive.
  */
 static enum contains_result contains_test(struct commit *candidate,
 			    const struct commit_list *want)
 {
 	/* was it previously marked as containing a want commit? */
 	if (candidate->object.flags & TMP_MARK)
 		return 1;
 	/* or marked as not possibly containing a want commit? */
 	if (candidate->object.flags & UNINTERESTING)
 		return 0;
 	/* or are we it? */
 	if (in_commit_list(want, candidate)) {
 		candidate->object.flags |= TMP_MARK;
 		return 1;
 	}

 	if (parse_commit(candidate) < 0)
 		return 0;

 	return -1;
 }

 /*
  * Mimicking the real stack, this stack lives on the heap, avoiding stack
  * overflows.
  *
  * At each recursion step, the stack items points to the commits whose
  * ancestors are to be inspected.
  */
 struct stack {
 	int nr, alloc;
 	struct stack_entry {
 		struct commit *commit;
 		struct commit_list *parents;
 	} *stack;
 };

 static void push_to_stack(struct commit *candidate, struct stack *stack)
 {
 	int index = stack->nr++;
 	ALLOC_GROW(stack->stack, stack->nr, stack->alloc);
 	stack->stack[index].commit = candidate;
 	stack->stack[index].parents = candidate->parents;
 }

 static enum contains_result contains(struct commit *candidate,
 		const struct commit_list *want)
 {
 	struct stack stack = { 0, 0, NULL };
 	int result = contains_test(candidate, want);

 	if (result != CONTAINS_UNKNOWN)
 		return result;

 	push_to_stack(candidate, &stack);
 	while (stack.nr) {
 		struct stack_entry *entry = &stack.stack[stack.nr - 1];
 		struct commit *commit = entry->commit;
 		struct commit_list *parents = entry->parents;

 		if (!parents) {
 			commit->object.flags |= UNINTERESTING;
 			stack.nr--;
 		}
 		/*
 		 * If we just popped the stack, parents->item has been marked,
 		 * therefore contains_test will return a meaningful 0 or 1.
 		 */
 		else switch (contains_test(parents->item, want)) {
 		case CONTAINS_YES:
 			commit->object.flags |= TMP_MARK;
 			stack.nr--;
 			break;
 		case CONTAINS_NO:
 			entry->parents = parents->next;
 			break;
 		case CONTAINS_UNKNOWN:
 			push_to_stack(parents->item, &stack);
 			break;
 		}
 	}
 	free(stack.stack);
 	return contains_test(candidate, want);
 }

 static void show_tag_lines(const unsigned char *sha1, int lines)
 {
 	int i;
 	unsigned long size;
 	enum object_type type;
 	char *buf, *sp, *eol;
 	size_t len;

 	buf = read_sha1_file(sha1, &type, &size);
 	if (!buf)
 		die_errno("unable to read object %s", sha1_to_hex(sha1));
 	if (type != OBJ_COMMIT && type != OBJ_TAG)
 		goto free_return;
 	if (!size)
 		die("an empty %s object %s?",
 		    typename(type), sha1_to_hex(sha1));

 	/* skip header */
 	sp = strstr(buf, "\n\n");
 	if (!sp)
 		goto free_return;

 	/* only take up to "lines" lines, and strip the signature from a tag */
 	if (type == OBJ_TAG)
 		size = parse_signature(buf, size);
 	for (i = 0, sp += 2; i < lines && sp < buf + size; 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;
 	}
 free_return:
 	free(buf);
 }

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

 	if (match_pattern(filter->patterns, refname)) {
 		if (filter->with_commit) {
 			struct commit *commit;

 			commit = lookup_commit_reference_gently(sha1, 1);
 			if (!commit)
 				return 0;
 			if (!contains(commit, filter->with_commit))
 				return 0;
 		}

 		if (points_at.nr && !match_points_at(refname, sha1))
 			return 0;

 		if (!filter->lines) {
 			if (filter->sort)
 				string_list_append(&filter->tags, refname);
 			else
 				printf("%s\n", refname);
 			return 0;
 		}
 		printf("%-15s ", refname);
 		show_tag_lines(sha1, filter->lines);
 		putchar('\n');
 	}

 	return 0;
 }

 static int sort_by_version(const void *a_, const void *b_)
 {
 	const struct string_list_item *a = a_;
 	const struct string_list_item *b = b_;
 	return versioncmp(a->string, b->string);
 }

 static int list_tags(const char **patterns, int lines,
 		     struct commit_list *with_commit, int sort)
 {
 	struct tag_filter filter;

 	filter.patterns = patterns;
 	filter.lines = lines;
 	filter.sort = sort;
 	filter.with_commit = with_commit;
 	memset(&filter.tags, 0, sizeof(filter.tags));
 	filter.tags.strdup_strings = 1;

 	for_each_tag_ref(show_reference, (void *) &filter);
 	if (sort) {
 		int i;
 		if ((sort & SORT_MASK) == VERCMP_SORT)
 			qsort(filter.tags.items, filter.tags.nr,
 			      sizeof(struct string_list_item), sort_by_version);
 		if (sort & REVERSE_SORT)
 			for (i = filter.tags.nr - 1; i >= 0; i--)
 				printf("%s\n", filter.tags.items[i].string);
 		else
 			for (i = 0; i < filter.tags.nr; i++)
 				printf("%s\n", filter.tags.items[i].string);
 		string_list_clear(&filter.tags, 0);
 	}
 	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 (read_ref(ref, sha1)) {
 			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, 0))
 		return 1;
 	printf(_("Deleted tag '%s' (was %s)\n"), name, find_unique_abbrev(sha1, DEFAULT_ABBREV));
 	return 0;
 }

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

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

 static int do_sign(struct strbuf *buffer)
 {
 	return sign_buffer(buffer, buffer, get_signing_key());
 }

 static const char tag_template[] =
 	N_("\nWrite a message for tag:\n  %s\n"
 	"Lines starting with '%c' will be ignored.\n");

 static const char tag_template_nocleanup[] =
 	N_("\nWrite a message for tag:\n  %s\n"
 	"Lines starting with '%c' will be kept; you may remove them"
 	" yourself if you want to.\n");

 /*
  * Parse a sort string, and return 0 if parsed successfully. Will return
  * non-zero when the sort string does not parse into a known type. If var is
  * given, the error message becomes a warning and includes information about
  * the configuration value.
  */
 static int parse_sort_string(const char *var, const char *arg, int *sort)
 {
 	int type = 0, flags = 0;

 	if (skip_prefix(arg, "-", &arg))
 		flags |= REVERSE_SORT;

 	if (skip_prefix(arg, "version:", &arg) || skip_prefix(arg, "v:", &arg))
 		type = VERCMP_SORT;
 	else
 		type = STRCMP_SORT;

 	if (strcmp(arg, "refname")) {
 		if (!var)
 			return error(_("unsupported sort specification '%s'"), arg);
 		else {
 			warning(_("unsupported sort specification '%s' in variable '%s'"),
 				var, arg);
 			return -1;
 		}
 	}

 	*sort = (type | flags);

 	return 0;
 }

 static int git_tag_config(const char *var, const char *value, void *cb)
 {
 	int status;

 	if (!strcmp(var, "tag.sort")) {
 		if (!value)
 			return config_error_nonbool(var);
 		parse_sort_string(var, value, &tag_sort);
 		return 0;
 	}

 	status = git_gpg_config(var, value, cb);
 	if (status)
 		return status;
 	if (starts_with(var, "column."))
 		return git_column_config(var, value, "tag", &colopts);
 	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;

 	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 */
 	write_or_die(fd, sp, parse_signature(sp, buf + size - sp));

 	free(buf);
 }

 static int build_tag_object(struct strbuf *buf, int sign, unsigned char *result)
 {
 	if (sign && do_sign(buf) < 0)
 		return error(_("unable to sign the tag"));
 	if (write_sha1_file(buf->buf, buf->len, tag_type, result) < 0)
 		return error(_("unable to write tag file"));
 	return 0;
 }

 struct create_tag_options {
 	unsigned int message_given:1;
 	unsigned int sign;
 	enum {
 		CLEANUP_NONE,
 		CLEANUP_SPACE,
 		CLEANUP_ALL
 	} cleanup_mode;
 };

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

 	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_STRICT));

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

 	if (!opt->message_given) {
 		int fd;

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

 		if (!is_null_sha1(prev)) {
 			write_tag_body(fd, prev);
 		} else {
 			struct strbuf buf = STRBUF_INIT;
 			strbuf_addch(&buf, '\n');
 			if (opt->cleanup_mode == CLEANUP_ALL)
 				strbuf_commented_addf(&buf, _(tag_template), tag, comment_line_char);
 			else
 				strbuf_commented_addf(&buf, _(tag_template_nocleanup), tag, comment_line_char);
 			write_or_die(fd, buf.buf, buf.len);
 			strbuf_release(&buf);
 		}
 		close(fd);

 		if (launch_editor(path, buf, NULL)) {
 			fprintf(stderr,
 			_("Please supply the message using either -m or -F option.\n"));
 			exit(1);
 		}
 	}

 	if (opt->cleanup_mode != CLEANUP_NONE)
 		stripspace(buf, opt->cleanup_mode == CLEANUP_ALL);

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

 	strbuf_insert(buf, 0, header_buf, header_len);

 	if (build_tag_object(buf, opt->sign, result) < 0) {
 		if (path)
 			fprintf(stderr, _("The tag message has been left in %s\n"),
 				path);
 		exit(128);
 	}
 	if (path) {
 		unlink_or_warn(path);
 		free(path);
 	}
 }

 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;
 }

 static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
 {
 	if (name[0] == '-')
 		return -1;

 	strbuf_reset(sb);
 	strbuf_addf(sb, "refs/tags/%s", name);

 	return check_refname_format(sb->buf, 0);
 }

 static int parse_opt_points_at(const struct option *opt __attribute__((unused)),
 			const char *arg, int unset)
 {
 	unsigned char sha1[20];

 	if (unset) {
 		sha1_array_clear(&points_at);
 		return 0;
 	}
 	if (!arg)
 		return error(_("switch 'points-at' requires an object"));
 	if (get_sha1(arg, sha1))
 		return error(_("malformed object name '%s'"), arg);
 	sha1_array_append(&points_at, sha1);
 	return 0;
 }

 static int parse_opt_sort(const struct option *opt, const char *arg, int unset)
 {
 	int *sort = opt->value;

 	return parse_sort_string(NULL, arg, sort);
 }

 int cmd_tag(int argc, const char **argv, const char *prefix)
 {
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf ref = STRBUF_INIT;
 	unsigned char object[20], prev[20];
 	const char *object_ref, *tag;
 	struct create_tag_options opt;
 	char *cleanup_arg = NULL;
 	int annotate = 0, force = 0, lines = -1;
 	int cmdmode = 0;
 	const char *msgfile = NULL, *keyid = NULL;
 	struct msg_arg msg = { 0, STRBUF_INIT };
 	struct commit_list *with_commit = NULL;
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 	struct option options[] = {
 		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
 		{ OPTION_INTEGER, 'n', NULL, &lines, N_("n"),
 				N_("print <n> lines of each tag message"),
 				PARSE_OPT_OPTARG, NULL, 1 },
 		OPT_CMDMODE('d', "delete", &cmdmode, N_("delete tags"), 'd'),
 		OPT_CMDMODE('v', "verify", &cmdmode, N_("verify tags"), 'v'),

 		OPT_GROUP(N_("Tag creation options")),
 		OPT_BOOL('a', "annotate", &annotate,
 					N_("annotated tag, needs a message")),
 		OPT_CALLBACK('m', "message", &msg, N_("message"),
 			     N_("tag message"), parse_msg_arg),
 		OPT_FILENAME('F', "file", &msgfile, N_("read message from file")),
 		OPT_BOOL('s', "sign", &opt.sign, N_("annotated and GPG-signed tag")),
 		OPT_STRING(0, "cleanup", &cleanup_arg, N_("mode"),
 			N_("how to strip spaces and #comments from message")),
 		OPT_STRING('u', "local-user", &keyid, N_("key-id"),
 					N_("use another key to sign the tag")),
 		OPT__FORCE(&force, N_("replace the tag if exists")),

 		OPT_GROUP(N_("Tag listing options")),
 		OPT_COLUMN(0, "column", &colopts, N_("show tag list in columns")),
 		{
 			OPTION_CALLBACK, 0, "sort", &tag_sort, N_("type"), N_("sort tags"),
 			PARSE_OPT_NONEG, parse_opt_sort
 		},
 		{
 			OPTION_CALLBACK, 0, "contains", &with_commit, N_("commit"),
 			N_("print only tags that contain the commit"),
 			PARSE_OPT_LASTARG_DEFAULT,
 			parse_opt_with_commit, (intptr_t)"HEAD",
 		},
 		{
 			OPTION_CALLBACK, 0, "with", &with_commit, N_("commit"),
 			N_("print only tags that contain the commit"),
 			PARSE_OPT_HIDDEN | PARSE_OPT_LASTARG_DEFAULT,
 			parse_opt_with_commit, (intptr_t)"HEAD",
 		},
 		{
 			OPTION_CALLBACK, 0, "points-at", NULL, N_("object"),
 			N_("print only tags of the object"), 0, parse_opt_points_at
 		},
 		OPT_END()
 	};

 	git_config(git_tag_config, NULL);

 	memset(&opt, 0, sizeof(opt));

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

 	if (keyid) {
 		opt.sign = 1;
 		set_signing_key(keyid);
 	}
 	if (opt.sign)
 		annotate = 1;
 	if (argc == 0 && !cmdmode)
 		cmdmode = 'l';

 	if ((annotate || msg.given || msgfile || force) && (cmdmode != 0))
 		usage_with_options(git_tag_usage, options);

 	finalize_colopts(&colopts, -1);
 	if (cmdmode == 'l' && lines != -1) {
 		if (explicitly_enable_column(colopts))
 			die(_("--column and -n are incompatible"));
 		colopts = 0;
 	}
 	if (cmdmode == 'l') {
 		int ret;
 		if (column_active(colopts)) {
 			struct column_options copts;
 			memset(&copts, 0, sizeof(copts));
 			copts.padding = 2;
 			run_column_filter(colopts, &copts);
 		}
 		if (lines != -1 && tag_sort)
 			die(_("--sort and -n are incompatible"));
 		ret = list_tags(argv, lines == -1 ? 0 : lines, with_commit, tag_sort);
 		if (column_active(colopts))
 			stop_column_filter();
 		return ret;
 	}
 	if (lines != -1)
 		die(_("-n option is only allowed with -l."));
 	if (with_commit)
 		die(_("--contains option is only allowed with -l."));
 	if (points_at.nr)
 		die(_("--points-at option is only allowed with -l."));
 	if (cmdmode == 'd')
 		return for_each_tag_name(argv, delete_tag);
 	if (cmdmode == 'v')
 		return for_each_tag_name(argv, verify_tag);

 	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_errno(_("cannot read '%s'"), msgfile);
 			} else {
 				if (strbuf_read_file(&buf, msgfile, 1024) < 0)
 					die_errno(_("could not open or read '%s'"),
 						msgfile);
 			}
 		}
 	}

 	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 (strbuf_check_tag_ref(&ref, tag))
 		die(_("'%s' is not a valid tag name."), tag);

 	if (read_ref(ref.buf, prev))
 		hashclr(prev);
 	else if (!force)
 		die(_("tag '%s' already exists"), tag);

 	opt.message_given = msg.given || msgfile;

 	if (!cleanup_arg || !strcmp(cleanup_arg, "strip"))
 		opt.cleanup_mode = CLEANUP_ALL;
 	else if (!strcmp(cleanup_arg, "verbatim"))
 		opt.cleanup_mode = CLEANUP_NONE;
 	else if (!strcmp(cleanup_arg, "whitespace"))
 		opt.cleanup_mode = CLEANUP_SPACE;
 	else
 		die(_("Invalid cleanup mode %s"), cleanup_arg);

 	if (annotate)
 		create_tag(object, tag, &buf, &opt, prev, object);

 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, ref.buf, object, prev,
 				   0, 1, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 	ref_transaction_free(transaction);
 	if (force && !is_null_sha1(prev) && hashcmp(prev, object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));

 	strbuf_release(&err);
 	strbuf_release(&buf);
 	strbuf_release(&ref);
 	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"
	#include "diff.h"
	#include "revision.h"
	#include "gpg-interface.h"
	#include "sha1-array.h"
	#include "column.h"

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

	#define STRCMP_SORT 0 /* must be zero */
	#define VERCMP_SORT 1
	#define SORT_MASK 0x7fff
	#define REVERSE_SORT 0x8000

	static int tag_sort;

	struct tag_filter {
	const char **patterns;
	int lines;
	int sort;
	struct string_list tags;
	struct commit_list *with_commit;
	};

	static struct sha1_array points_at;
	static unsigned int colopts;

	static int match_pattern(const char *patterns, const char ref)
	{
	/* no pattern means match everything */
	if (!*patterns)
	return 1;
	for (; *patterns; patterns++)
	if (!wildmatch(*patterns, ref, 0, NULL))
	return 1;
	return 0;
	}

	static const unsigned char match_points_at(const char refname,
	const unsigned char *sha1)
	{
	const unsigned char *tagged_sha1 = NULL;
	struct object *obj;

	if (sha1_array_lookup(&points_at, sha1) >= 0)
	return sha1;
	obj = parse_object(sha1);
	if (!obj)
	die(_("malformed object at '%s'"), refname);
	if (obj->type == OBJ_TAG)
	tagged_sha1 = ((struct tag *)obj)->tagged->sha1;
	if (tagged_sha1 && sha1_array_lookup(&points_at, tagged_sha1) >= 0)
	return tagged_sha1;
	return NULL;
	}

	static int in_commit_list(const struct commit_list want, struct commit c)
	{
	for (; want; want = want->next)
	if (!hashcmp(want->item->object.sha1, c->object.sha1))
	return 1;
	return 0;
	}

	enum contains_result {
	CONTAINS_UNKNOWN = -1,
	CONTAINS_NO = 0,
	CONTAINS_YES = 1
	};

	/*
	* Test whether the candidate or one of its parents is contained in the list.
	* Do not recurse to find out, though, but return -1 if inconclusive.
	*/
	static enum contains_result contains_test(struct commit *candidate,
	const struct commit_list *want)
	{
	/* was it previously marked as containing a want commit? */
	if (candidate->object.flags & TMP_MARK)
	return 1;
	/* or marked as not possibly containing a want commit? */
	if (candidate->object.flags & UNINTERESTING)
	return 0;
	/* or are we it? */
	if (in_commit_list(want, candidate)) {
	candidate->object.flags \|= TMP_MARK;
	return 1;
	}

	if (parse_commit(candidate) < 0)
	return 0;

	return -1;
	}

	/*
	* Mimicking the real stack, this stack lives on the heap, avoiding stack
	* overflows.
	*
	* At each recursion step, the stack items points to the commits whose
	* ancestors are to be inspected.
	*/
	struct stack {
	int nr, alloc;
	struct stack_entry {
	struct commit *commit;
	struct commit_list *parents;
	} *stack;
	};

	static void push_to_stack(struct commit candidate, struct stack stack)
	{
	int index = stack->nr++;
	ALLOC_GROW(stack->stack, stack->nr, stack->alloc);
	stack->stack[index].commit = candidate;
	stack->stack[index].parents = candidate->parents;
	}

	static enum contains_result contains(struct commit *candidate,
	const struct commit_list *want)
	{
	struct stack stack = { 0, 0, NULL };
	int result = contains_test(candidate, want);

	if (result != CONTAINS_UNKNOWN)
	return result;

	push_to_stack(candidate, &stack);
	while (stack.nr) {
	struct stack_entry *entry = &stack.stack[stack.nr - 1];
	struct commit *commit = entry->commit;
	struct commit_list *parents = entry->parents;

	if (!parents) {
	commit->object.flags \|= UNINTERESTING;
	stack.nr--;
	}
	/*
	* If we just popped the stack, parents->item has been marked,
	* therefore contains_test will return a meaningful 0 or 1.
	*/
	else switch (contains_test(parents->item, want)) {
	case CONTAINS_YES:
	commit->object.flags \|= TMP_MARK;
	stack.nr--;
	break;
	case CONTAINS_NO:
	entry->parents = parents->next;
	break;
	case CONTAINS_UNKNOWN:
	push_to_stack(parents->item, &stack);
	break;
	}
	}
	free(stack.stack);
	return contains_test(candidate, want);
	}

	static void show_tag_lines(const unsigned char *sha1, int lines)
	{
	int i;
	unsigned long size;
	enum object_type type;
	char buf, sp, *eol;
	size_t len;

	buf = read_sha1_file(sha1, &type, &size);
	if (!buf)
	die_errno("unable to read object %s", sha1_to_hex(sha1));
	if (type != OBJ_COMMIT && type != OBJ_TAG)
	goto free_return;
	if (!size)
	die("an empty %s object %s?",
	typename(type), sha1_to_hex(sha1));

	/* skip header */
	sp = strstr(buf, "\n\n");
	if (!sp)
	goto free_return;

	/* only take up to "lines" lines, and strip the signature from a tag */
	if (type == OBJ_TAG)
	size = parse_signature(buf, size);
	for (i = 0, sp += 2; i < lines && sp < buf + size; 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;
	}
	free_return:
	free(buf);
	}

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

	if (match_pattern(filter->patterns, refname)) {
	if (filter->with_commit) {
	struct commit *commit;

	commit = lookup_commit_reference_gently(sha1, 1);
	if (!commit)
	return 0;
	if (!contains(commit, filter->with_commit))
	return 0;
	}

	if (points_at.nr && !match_points_at(refname, sha1))
	return 0;

	if (!filter->lines) {
	if (filter->sort)
	string_list_append(&filter->tags, refname);
	else
	printf("%s\n", refname);
	return 0;
	}
	printf("%-15s ", refname);
	show_tag_lines(sha1, filter->lines);
	putchar('\n');
	}

	return 0;
	}

	static int sort_by_version(const void a_, const void b_)
	{
	const struct string_list_item *a = a_;
	const struct string_list_item *b = b_;
	return versioncmp(a->string, b->string);
	}

	static int list_tags(const char **patterns, int lines,
	struct commit_list *with_commit, int sort)
	{
	struct tag_filter filter;

	filter.patterns = patterns;
	filter.lines = lines;
	filter.sort = sort;
	filter.with_commit = with_commit;
	memset(&filter.tags, 0, sizeof(filter.tags));
	filter.tags.strdup_strings = 1;

	for_each_tag_ref(show_reference, (void *) &filter);
	if (sort) {
	int i;
	if ((sort & SORT_MASK) == VERCMP_SORT)
	qsort(filter.tags.items, filter.tags.nr,
	sizeof(struct string_list_item), sort_by_version);
	if (sort & REVERSE_SORT)
	for (i = filter.tags.nr - 1; i >= 0; i--)
	printf("%s\n", filter.tags.items[i].string);
	else
	for (i = 0; i < filter.tags.nr; i++)
	printf("%s\n", filter.tags.items[i].string);
	string_list_clear(&filter.tags, 0);
	}
	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 (read_ref(ref, sha1)) {
	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, 0))
	return 1;
	printf(_("Deleted tag '%s' (was %s)\n"), name, find_unique_abbrev(sha1, DEFAULT_ABBREV));
	return 0;
	}

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

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

	static int do_sign(struct strbuf *buffer)
	{
	return sign_buffer(buffer, buffer, get_signing_key());
	}

	static const char tag_template[] =
	N_("\nWrite a message for tag:\n %s\n"
	"Lines starting with '%c' will be ignored.\n");

	static const char tag_template_nocleanup[] =
	N_("\nWrite a message for tag:\n %s\n"
	"Lines starting with '%c' will be kept; you may remove them"
	" yourself if you want to.\n");

	/*
	* Parse a sort string, and return 0 if parsed successfully. Will return
	* non-zero when the sort string does not parse into a known type. If var is
	* given, the error message becomes a warning and includes information about
	* the configuration value.
	*/
	static int parse_sort_string(const char var, const char arg, int *sort)
	{
	int type = 0, flags = 0;

	if (skip_prefix(arg, "-", &arg))
	flags \|= REVERSE_SORT;

	if (skip_prefix(arg, "version:", &arg) \|\| skip_prefix(arg, "v:", &arg))
	type = VERCMP_SORT;
	else
	type = STRCMP_SORT;

	if (strcmp(arg, "refname")) {
	if (!var)
	return error(_("unsupported sort specification '%s'"), arg);
	else {
	warning(_("unsupported sort specification '%s' in variable '%s'"),
	var, arg);
	return -1;
	}
	}

	*sort = (type \| flags);

	return 0;
	}

	static int git_tag_config(const char var, const char value, void *cb)
	{
	int status;

	if (!strcmp(var, "tag.sort")) {
	if (!value)
	return config_error_nonbool(var);
	parse_sort_string(var, value, &tag_sort);
	return 0;
	}

	status = git_gpg_config(var, value, cb);
	if (status)
	return status;
	if (starts_with(var, "column."))
	return git_column_config(var, value, "tag", &colopts);
	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;

	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 */
	write_or_die(fd, sp, parse_signature(sp, buf + size - sp));

	free(buf);
	}

	static int build_tag_object(struct strbuf buf, int sign, unsigned char result)
	{
	if (sign && do_sign(buf) < 0)
	return error(_("unable to sign the tag"));
	if (write_sha1_file(buf->buf, buf->len, tag_type, result) < 0)
	return error(_("unable to write tag file"));
	return 0;
	}

	struct create_tag_options {
	unsigned int message_given:1;
	unsigned int sign;
	enum {
	CLEANUP_NONE,
	CLEANUP_SPACE,
	CLEANUP_ALL
	} cleanup_mode;
	};

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

	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_STRICT));

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

	if (!opt->message_given) {
	int fd;

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

	if (!is_null_sha1(prev)) {
	write_tag_body(fd, prev);
	} else {
	struct strbuf buf = STRBUF_INIT;
	strbuf_addch(&buf, '\n');
	if (opt->cleanup_mode == CLEANUP_ALL)
	strbuf_commented_addf(&buf, _(tag_template), tag, comment_line_char);
	else
	strbuf_commented_addf(&buf, _(tag_template_nocleanup), tag, comment_line_char);
	write_or_die(fd, buf.buf, buf.len);
	strbuf_release(&buf);
	}
	close(fd);

	if (launch_editor(path, buf, NULL)) {
	fprintf(stderr,
	_("Please supply the message using either -m or -F option.\n"));
	exit(1);
	}
	}

	if (opt->cleanup_mode != CLEANUP_NONE)
	stripspace(buf, opt->cleanup_mode == CLEANUP_ALL);

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

	strbuf_insert(buf, 0, header_buf, header_len);

	if (build_tag_object(buf, opt->sign, result) < 0) {
	if (path)
	fprintf(stderr, _("The tag message has been left in %s\n"),
	path);
	exit(128);
	}
	if (path) {
	unlink_or_warn(path);
	free(path);
	}
	}

	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;
	}

	static int strbuf_check_tag_ref(struct strbuf sb, const char name)
	{
	if (name[0] == '-')
	return -1;

	strbuf_reset(sb);
	strbuf_addf(sb, "refs/tags/%s", name);

	return check_refname_format(sb->buf, 0);
	}

	static int parse_opt_points_at(const struct option *opt __attribute__((unused)),
	const char *arg, int unset)
	{
	unsigned char sha1[20];

	if (unset) {
	sha1_array_clear(&points_at);
	return 0;
	}
	if (!arg)
	return error(_("switch 'points-at' requires an object"));
	if (get_sha1(arg, sha1))
	return error(_("malformed object name '%s'"), arg);
	sha1_array_append(&points_at, sha1);
	return 0;
	}

	static int parse_opt_sort(const struct option opt, const char arg, int unset)
	{
	int *sort = opt->value;

	return parse_sort_string(NULL, arg, sort);
	}

	int cmd_tag(int argc, const char *argv, const char prefix)
	{
	struct strbuf buf = STRBUF_INIT;
	struct strbuf ref = STRBUF_INIT;
	unsigned char object[20], prev[20];
	const char object_ref, tag;
	struct create_tag_options opt;
	char *cleanup_arg = NULL;
	int annotate = 0, force = 0, lines = -1;
	int cmdmode = 0;
	const char msgfile = NULL, keyid = NULL;
	struct msg_arg msg = { 0, STRBUF_INIT };
	struct commit_list *with_commit = NULL;
	struct ref_transaction *transaction;
	struct strbuf err = STRBUF_INIT;
	struct option options[] = {
	OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
	{ OPTION_INTEGER, 'n', NULL, &lines, N_("n"),
	N_("print <n> lines of each tag message"),
	PARSE_OPT_OPTARG, NULL, 1 },
	OPT_CMDMODE('d', "delete", &cmdmode, N_("delete tags"), 'd'),
	OPT_CMDMODE('v', "verify", &cmdmode, N_("verify tags"), 'v'),

	OPT_GROUP(N_("Tag creation options")),
	OPT_BOOL('a', "annotate", &annotate,
	N_("annotated tag, needs a message")),
	OPT_CALLBACK('m', "message", &msg, N_("message"),
	N_("tag message"), parse_msg_arg),
	OPT_FILENAME('F', "file", &msgfile, N_("read message from file")),
	OPT_BOOL('s', "sign", &opt.sign, N_("annotated and GPG-signed tag")),
	OPT_STRING(0, "cleanup", &cleanup_arg, N_("mode"),
	N_("how to strip spaces and #comments from message")),
	OPT_STRING('u', "local-user", &keyid, N_("key-id"),
	N_("use another key to sign the tag")),
	OPT__FORCE(&force, N_("replace the tag if exists")),

	OPT_GROUP(N_("Tag listing options")),
	OPT_COLUMN(0, "column", &colopts, N_("show tag list in columns")),
	{
	OPTION_CALLBACK, 0, "sort", &tag_sort, N_("type"), N_("sort tags"),
	PARSE_OPT_NONEG, parse_opt_sort
	},
	{
	OPTION_CALLBACK, 0, "contains", &with_commit, N_("commit"),
	N_("print only tags that contain the commit"),
	PARSE_OPT_LASTARG_DEFAULT,
	parse_opt_with_commit, (intptr_t)"HEAD",
	},
	{
	OPTION_CALLBACK, 0, "with", &with_commit, N_("commit"),
	N_("print only tags that contain the commit"),
	PARSE_OPT_HIDDEN \| PARSE_OPT_LASTARG_DEFAULT,
	parse_opt_with_commit, (intptr_t)"HEAD",
	},
	{
	OPTION_CALLBACK, 0, "points-at", NULL, N_("object"),
	N_("print only tags of the object"), 0, parse_opt_points_at
	},
	OPT_END()
	};

	git_config(git_tag_config, NULL);

	memset(&opt, 0, sizeof(opt));

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

	if (keyid) {
	opt.sign = 1;
	set_signing_key(keyid);
	}
	if (opt.sign)
	annotate = 1;
	if (argc == 0 && !cmdmode)
	cmdmode = 'l';

	if ((annotate \|\| msg.given \|\| msgfile \|\| force) && (cmdmode != 0))
	usage_with_options(git_tag_usage, options);

	finalize_colopts(&colopts, -1);
	if (cmdmode == 'l' && lines != -1) {
	if (explicitly_enable_column(colopts))
	die(_("--column and -n are incompatible"));
	colopts = 0;
	}
	if (cmdmode == 'l') {
	int ret;
	if (column_active(colopts)) {
	struct column_options copts;
	memset(&copts, 0, sizeof(copts));
	copts.padding = 2;
	run_column_filter(colopts, &copts);
	}
	if (lines != -1 && tag_sort)
	die(_("--sort and -n are incompatible"));
	ret = list_tags(argv, lines == -1 ? 0 : lines, with_commit, tag_sort);
	if (column_active(colopts))
	stop_column_filter();
	return ret;
	}
	if (lines != -1)
	die(_("-n option is only allowed with -l."));
	if (with_commit)
	die(_("--contains option is only allowed with -l."));
	if (points_at.nr)
	die(_("--points-at option is only allowed with -l."));
	if (cmdmode == 'd')
	return for_each_tag_name(argv, delete_tag);
	if (cmdmode == 'v')
	return for_each_tag_name(argv, verify_tag);

	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_errno(_("cannot read '%s'"), msgfile);
	} else {
	if (strbuf_read_file(&buf, msgfile, 1024) < 0)
	die_errno(_("could not open or read '%s'"),
	msgfile);
	}
	}
	}

	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 (strbuf_check_tag_ref(&ref, tag))
	die(_("'%s' is not a valid tag name."), tag);

	if (read_ref(ref.buf, prev))
	hashclr(prev);
	else if (!force)
	die(_("tag '%s' already exists"), tag);

	opt.message_given = msg.given \|\| msgfile;

	if (!cleanup_arg \|\| !strcmp(cleanup_arg, "strip"))
	opt.cleanup_mode = CLEANUP_ALL;
	else if (!strcmp(cleanup_arg, "verbatim"))
	opt.cleanup_mode = CLEANUP_NONE;
	else if (!strcmp(cleanup_arg, "whitespace"))
	opt.cleanup_mode = CLEANUP_SPACE;
	else
	die(_("Invalid cleanup mode %s"), cleanup_arg);

	if (annotate)
	create_tag(object, tag, &buf, &opt, prev, object);

	transaction = ref_transaction_begin(&err);
	if (!transaction \|\|
	ref_transaction_update(transaction, ref.buf, object, prev,
	0, 1, NULL, &err) \|\|
	ref_transaction_commit(transaction, &err))
	die("%s", err.buf);
	ref_transaction_free(transaction);
	if (force && !is_null_sha1(prev) && hashcmp(prev, object))
	printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));

	strbuf_release(&err);
	strbuf_release(&buf);
	strbuf_release(&ref);
	return 0;
	}