static int read_tree_trivial(unsigned char *common, unsigned char *head,
			     unsigned char *one)
{
	int i, nr_trees = 0;
	struct tree *trees[MAX_UNPACK_TREES];
	struct tree_desc t[MAX_UNPACK_TREES];
	struct unpack_trees_options opts;

	memset(&opts, 0, sizeof(opts));
	opts.head_idx = 2;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;
	opts.update = 1;
	opts.verbose_update = 1;
	opts.trivial_merges_only = 1;
	opts.merge = 1;
	trees[nr_trees] = parse_tree_indirect(common);
	if (!trees[nr_trees++])
		return -1;
	trees[nr_trees] = parse_tree_indirect(head);
	if (!trees[nr_trees++])
		return -1;
	trees[nr_trees] = parse_tree_indirect(one);
	if (!trees[nr_trees++])
		return -1;
	opts.fn = threeway_merge;
	cache_tree_free(&active_cache_tree);
	for (i = 0; i < nr_trees; i++) {
		parse_tree(trees[i]);
		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
	}
	if (unpack_trees(nr_trees, t, &opts))
		return -1;
	return 0;
}

static void parse_treeish_arg(const char **argv,
		struct archiver_args *ar_args, const char *prefix,
		int remote)
{
	const char *name = argv[0];
	const unsigned char *commit_sha1;
	time_t archive_time;
	struct tree *tree;
	const struct commit *commit;
	struct object_id oid;

	/* Remotes are only allowed to fetch actual refs */
	if (remote && !remote_allow_unreachable) {
		char *ref = NULL;
		const char *colon = strchrnul(name, ':');
		int refnamelen = colon - name;

		if (!dwim_ref(name, refnamelen, &oid, &ref))
			die(_("no such ref: %.*s"), refnamelen, name);
		free(ref);
	}

	if (get_oid(name, &oid))
		die(_("not a valid object name: %s"), name);

	commit = lookup_commit_reference_gently(ar_args->repo, &oid, 1);
	if (commit) {
		commit_sha1 = commit->object.oid.hash;
		archive_time = commit->date;
	} else {
		commit_sha1 = NULL;
		archive_time = time(NULL);
	}

	tree = parse_tree_indirect(&oid);
	if (tree == NULL)
		die(_("not a tree object: %s"), oid_to_hex(&oid));

	if (prefix) {
		struct object_id tree_oid;
		unsigned int mode;
		int err;

		err = get_tree_entry(&tree->object.oid, prefix, &tree_oid,
				     &mode);
		if (err || !S_ISDIR(mode))
			die(_("current working directory is untracked"));

		tree = parse_tree_indirect(&tree_oid);
	}
	ar_args->tree = tree;
	ar_args->commit_sha1 = commit_sha1;
	ar_args->commit = commit;
	ar_args->time = archive_time;
}

static void parse_treeish_arg(const char **argv,
		struct archiver_args *ar_args, const char *prefix,
		int remote)
{
	const char *name = argv[0];
	const unsigned char *commit_sha1;
	time_t archive_time;
	struct tree *tree;
	const struct commit *commit;
	unsigned char sha1[20];

	/* Remotes are only allowed to fetch actual refs */
	if (remote && !remote_allow_unreachable) {
		char *ref = NULL;
		const char *colon = strchr(name, ':');
		int refnamelen = colon ? colon - name : strlen(name);

		if (!dwim_ref(name, refnamelen, sha1, &ref))
			die("no such ref: %.*s", refnamelen, name);
		free(ref);
	}

	if (get_sha1(name, sha1))
		die("Not a valid object name");

	commit = lookup_commit_reference_gently(sha1, 1);
	if (commit) {
		commit_sha1 = commit->object.sha1;
		archive_time = commit->date;
	} else {
		commit_sha1 = NULL;
		archive_time = time(NULL);
	}

	tree = parse_tree_indirect(sha1);
	if (tree == NULL)
		die("not a tree object");

	if (prefix) {
		unsigned char tree_sha1[20];
		unsigned int mode;
		int err;

		err = get_tree_entry(tree->object.sha1, prefix,
				     tree_sha1, &mode);
		if (err || !S_ISDIR(mode))
			die("current working directory is untracked");

		tree = parse_tree_indirect(tree_sha1);
	}
	ar_args->tree = tree;
	ar_args->commit_sha1 = commit_sha1;
	ar_args->commit = commit;
	ar_args->time = archive_time;
}

int checkout_fast_forward(const unsigned char *head,
			  const unsigned char *remote,
			  int overwrite_ignore)
{
	struct tree *trees[MAX_UNPACK_TREES];
	struct unpack_trees_options opts;
	struct tree_desc t[MAX_UNPACK_TREES];
	int i, nr_trees = 0;
	struct dir_struct dir;
	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));

	refresh_cache(REFRESH_QUIET);

	hold_locked_index(lock_file, 1);

	memset(&trees, 0, sizeof(trees));
	memset(&opts, 0, sizeof(opts));
	memset(&t, 0, sizeof(t));
	if (overwrite_ignore) {
		memset(&dir, 0, sizeof(dir));
		dir.flags |= DIR_SHOW_IGNORED;
		setup_standard_excludes(&dir);
		opts.dir = &dir;
	}

	opts.head_idx = 1;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;
	opts.update = 1;
	opts.verbose_update = 1;
	opts.merge = 1;
	opts.fn = twoway_merge;
	setup_unpack_trees_porcelain(&opts, "merge");

	trees[nr_trees] = parse_tree_indirect(head);
	if (!trees[nr_trees++])
		return -1;
	trees[nr_trees] = parse_tree_indirect(remote);
	if (!trees[nr_trees++])
		return -1;
	for (i = 0; i < nr_trees; i++) {
		parse_tree(trees[i]);
		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
	}
	if (unpack_trees(nr_trees, t, &opts))
		return -1;
	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
		die(_("unable to write new index file"));
	return 0;
}

static int diff_cache(struct rev_info *revs,
		      const struct object_id *tree_oid,
		      const char *tree_name,
		      int cached)
{
	struct tree *tree;
	struct tree_desc t;
	struct unpack_trees_options opts;

	tree = parse_tree_indirect(tree_oid);
	if (!tree)
		return error("bad tree object %s",
			     tree_name ? tree_name : oid_to_hex(tree_oid));
	memset(&opts, 0, sizeof(opts));
	opts.head_idx = 1;
	opts.index_only = cached;
	opts.diff_index_cached = (cached &&
				  !revs->diffopt.flags.find_copies_harder);
	opts.merge = 1;
	opts.fn = oneway_diff;
	opts.unpack_data = revs;
	opts.src_index = revs->diffopt.repo->index;
	opts.dst_index = NULL;
	opts.pathspec = &revs->diffopt.pathspec;
	opts.pathspec->recursive = 1;

	init_tree_desc(&t, tree->buffer, tree->size);
	return unpack_trees(1, &t, &opts);
}

static int checkout(void)
{
	unsigned char sha1[20];
	char *head;
	struct lock_file *lock_file;
	struct unpack_trees_options opts;
	struct tree *tree;
	struct tree_desc t;
	int err = 0, fd;

	if (option_no_checkout)
		return 0;

	head = resolve_refdup("HEAD", sha1, 1, NULL);
	if (!head) {
		warning(_("remote HEAD refers to nonexistent ref, "
			  "unable to checkout.\n"));
		return 0;
	}
	if (!strcmp(head, "HEAD")) {
		if (advice_detached_head)
			detach_advice(sha1_to_hex(sha1));
	} else {
		if (prefixcmp(head, "refs/heads/"))
			die(_("HEAD not found below refs/heads!"));
	}
	free(head);

	/* We need to be in the new work tree for the checkout */
	setup_work_tree();

	lock_file = xcalloc(1, sizeof(struct lock_file));
	fd = hold_locked_index(lock_file, 1);

	memset(&opts, 0, sizeof opts);
	opts.update = 1;
	opts.merge = 1;
	opts.fn = oneway_merge;
	opts.verbose_update = (option_verbosity >= 0);
	opts.src_index = &the_index;
	opts.dst_index = &the_index;

	tree = parse_tree_indirect(sha1);
	parse_tree(tree);
	init_tree_desc(&t, tree->buffer, tree->size);
	if (unpack_trees(1, &t, &opts) < 0)
		die(_("unable to checkout working tree"));

	if (write_cache(fd, active_cache, active_nr) ||
	    commit_locked_index(lock_file))
		die(_("unable to write new index file"));

	err |= run_hook(NULL, "post-checkout", sha1_to_hex(null_sha1),
			sha1_to_hex(sha1), "1", NULL);

	if (!err && option_recursive)
		err = run_command_v_opt(argv_submodule, RUN_GIT_CMD);

	return err;
}

static void create_base_index(const struct commit *current_head)
{
	struct tree *tree;
	struct unpack_trees_options opts;
	struct tree_desc t;

	if (!current_head) {
		discard_cache();
		return;
	}

	memset(&opts, 0, sizeof(opts));
	opts.head_idx = 1;
	opts.index_only = 1;
	opts.merge = 1;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;

	opts.fn = oneway_merge;
	tree = parse_tree_indirect(current_head->object.sha1);
	if (!tree)
		die(_("failed to unpack HEAD tree object"));
	parse_tree(tree);
	init_tree_desc(&t, tree->buffer, tree->size);
	if (unpack_trees(1, &t, &opts))
		exit(128); /* We've already reported the error, finish dying */
}

static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
{
	struct tree *trees[MAX_UNPACK_TREES];
	struct unpack_trees_options opts;
	struct tree_desc t[MAX_UNPACK_TREES];
	int i, fd, nr_trees = 0;
	struct dir_struct dir;
	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));

	refresh_cache(REFRESH_QUIET);

	fd = hold_locked_index(lock_file, 1);

	memset(&trees, 0, sizeof(trees));
	memset(&opts, 0, sizeof(opts));
	memset(&t, 0, sizeof(t));
	memset(&dir, 0, sizeof(dir));
	dir.flags |= DIR_SHOW_IGNORED;
	dir.exclude_per_dir = ".gitignore";
	opts.dir = &dir;

	opts.head_idx = 1;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;
	opts.update = 1;
	opts.verbose_update = 1;
	opts.merge = 1;
	opts.fn = twoway_merge;
	opts.msgs = get_porcelain_error_msgs();

	trees[nr_trees] = parse_tree_indirect(head);
	if (!trees[nr_trees++])
		return -1;
	trees[nr_trees] = parse_tree_indirect(remote);
	if (!trees[nr_trees++])
		return -1;
	for (i = 0; i < nr_trees; i++) {
		parse_tree(trees[i]);
		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
	}
	if (unpack_trees(nr_trees, t, &opts))
		return -1;
	if (write_cache(fd, active_cache, active_nr) ||
		commit_locked_index(lock_file))
		die("unable to write new index file");
	return 0;
}

static int do_recursive_merge(struct commit *base, struct commit *next,
			      const char *base_label, const char *next_label,
			      unsigned char *head, struct strbuf *msgbuf,
			      struct replay_opts *opts)
{
	struct merge_options o;
	struct tree *result, *next_tree, *base_tree, *head_tree;
	int clean, index_fd;
	const char **xopt;
	static struct lock_file index_lock;

	index_fd = hold_locked_index(&index_lock, 1);

	read_cache();

	init_merge_options(&o);
	o.ancestor = base ? base_label : "(empty tree)";
	o.branch1 = "HEAD";
	o.branch2 = next ? next_label : "(empty tree)";

	head_tree = parse_tree_indirect(head);
	next_tree = next ? next->tree : empty_tree();
	base_tree = base ? base->tree : empty_tree();

	for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
		parse_merge_opt(&o, *xopt);

	clean = merge_trees(&o,
			    head_tree,
			    next_tree, base_tree, &result);

	if (active_cache_changed &&
	    (write_cache(index_fd, active_cache, active_nr) ||
	     commit_locked_index(&index_lock)))
		/* TRANSLATORS: %s will be "revert" or "cherry-pick" */
		die(_("%s: Unable to write new index file"), action_name(opts));
	rollback_lock_file(&index_lock);

	if (opts->signoff)
		append_signoff(msgbuf, 0, 0);

	if (!clean) {
		int i;
		strbuf_addstr(msgbuf, "\nConflicts:\n");
		for (i = 0; i < active_nr;) {
			const struct cache_entry *ce = active_cache[i++];
			if (ce_stage(ce)) {
				strbuf_addch(msgbuf, '\t');
				strbuf_addstr(msgbuf, ce->name);
				strbuf_addch(msgbuf, '\n');
				while (i < active_nr && !strcmp(ce->name,
						active_cache[i]->name))
					i++;
			}
		}
	}

	return !clean;
}

static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
{
	struct tree *trees[MAX_UNPACK_TREES];
	struct unpack_trees_options opts;
	struct tree_desc t[MAX_UNPACK_TREES];
	int i, fd, nr_trees = 0;
	struct dir_struct dir;
	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));

	if (read_cache_unmerged())
		die("you need to resolve your current index first");

	fd = hold_locked_index(lock_file, 1);

	memset(&trees, 0, sizeof(trees));
	memset(&opts, 0, sizeof(opts));
	memset(&t, 0, sizeof(t));
	dir.show_ignored = 1;
	dir.exclude_per_dir = ".gitignore";
	opts.dir = &dir;

	opts.head_idx = 1;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;
	opts.update = 1;
	opts.verbose_update = 1;
	opts.merge = 1;
	opts.fn = twoway_merge;

	trees[nr_trees] = parse_tree_indirect(head);
	if (!trees[nr_trees++])
		return -1;
	trees[nr_trees] = parse_tree_indirect(remote);
	if (!trees[nr_trees++])
		return -1;
	for (i = 0; i < nr_trees; i++) {
		parse_tree(trees[i]);
		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
	}
	if (unpack_trees(nr_trees, t, &opts))
		return -1;
	if (write_cache(fd, active_cache, active_nr) ||
		commit_locked_index(lock_file))
		die("unable to write new index file");
	return 0;
}

static void parse_treeish_arg(const char **argv,
		struct archiver_args *ar_args, const char *prefix)
{
	const char *name = argv[0];
	const unsigned char *commit_sha1;
	time_t archive_time;
	struct tree *tree;
	const struct commit *commit;
	unsigned char sha1[20];

	if (get_sha1(name, sha1))
		die("Not a valid object name");

	commit = lookup_commit_reference_gently(sha1, 1);
	if (commit) {
		commit_sha1 = commit->object.sha1;
		archive_time = commit->date;
	} else {
		commit_sha1 = NULL;
		archive_time = time(NULL);
	}

	tree = parse_tree_indirect(sha1);
	if (tree == NULL)
		die("not a tree object");

	if (prefix) {
		unsigned char tree_sha1[20];
		unsigned int mode;
		int err;

		err = get_tree_entry(tree->object.sha1, prefix,
				     tree_sha1, &mode);
		if (err || !S_ISDIR(mode))
			die("current working directory is untracked");

		tree = parse_tree_indirect(tree_sha1);
	}
	ar_args->tree = tree;
	ar_args->commit_sha1 = commit_sha1;
	ar_args->commit = commit;
	ar_args->time = archive_time;
}

static void do_recursive_merge(struct commit *base, struct commit *next,
			       const char *base_label, const char *next_label,
			       unsigned char *head, struct strbuf *msgbuf,
			       char *defmsg)
{
	struct merge_options o;
	struct tree *result, *next_tree, *base_tree, *head_tree;
	int clean, index_fd;
	static struct lock_file index_lock;

	index_fd = hold_locked_index(&index_lock, 1);

	read_cache();
	init_merge_options(&o);
	o.ancestor = base ? base_label : "(empty tree)";
	o.branch1 = "HEAD";
	o.branch2 = next ? next_label : "(empty tree)";

	head_tree = parse_tree_indirect(head);
	next_tree = next ? next->tree : empty_tree();
	base_tree = base ? base->tree : empty_tree();

	clean = merge_trees(&o,
			    head_tree,
			    next_tree, base_tree, &result);

	if (active_cache_changed &&
	    (write_cache(index_fd, active_cache, active_nr) ||
	     commit_locked_index(&index_lock)))
		die("%s: Unable to write new index file", me);
	rollback_lock_file(&index_lock);

	if (!clean) {
		int i;
		strbuf_addstr(msgbuf, "\nConflicts:\n\n");
		for (i = 0; i < active_nr;) {
			struct cache_entry *ce = active_cache[i++];
			if (ce_stage(ce)) {
				strbuf_addch(msgbuf, '\t');
				strbuf_addstr(msgbuf, ce->name);
				strbuf_addch(msgbuf, '\n');
				while (i < active_nr && !strcmp(ce->name,
						active_cache[i]->name))
					i++;
			}
		}
		write_message(msgbuf, defmsg);
		fprintf(stderr, "Automatic %s failed.%s\n",
			me, help_msg());
		rerere(allow_rerere_auto);
		exit(1);
	}
	write_message(msgbuf, defmsg);
	fprintf(stderr, "Finished one %s.\n", me);
}

static int list_tree(unsigned char *sha1)
{
	struct tree *tree;

	if (nr_trees >= MAX_UNPACK_TREES)
		die("I cannot read more than %d trees", MAX_UNPACK_TREES);
	tree = parse_tree_indirect(sha1);
	if (!tree)
		return -1;
	trees[nr_trees++] = tree;
	return 0;
}

static int list_tree(struct object_id *oid)
{
	struct tree *tree;

	if (nr_trees >= MAX_UNPACK_TREES)
		die("I cannot read more than %d trees", MAX_UNPACK_TREES);
	tree = parse_tree_indirect(oid);
	if (!tree)
		return -1;
	trees[nr_trees++] = tree;
	return 0;
}

/*
 * Read the tree specified with --with-tree option
 * (typically, HEAD) into stage #1 and then
 * squash them down to stage #0.  This is used for
 * --error-unmatch to list and check the path patterns
 * that were given from the command line.  We are not
 * going to write this index out.
 */
void overlay_tree_on_cache(const char *tree_name, const char *prefix)
{
	struct tree *tree;
	unsigned char sha1[20];
	const char **match;
	struct cache_entry *last_stage0 = NULL;
	int i;

	if (get_sha1(tree_name, sha1))
		die("tree-ish %s not found.", tree_name);
	tree = parse_tree_indirect(sha1);
	if (!tree)
		die("bad tree-ish %s", tree_name);

	/* Hoist the unmerged entries up to stage #3 to make room */
	for (i = 0; i < active_nr; i++) {
		struct cache_entry *ce = active_cache[i];
		if (!ce_stage(ce))
			continue;
		ce->ce_flags |= CE_STAGEMASK;
	}

	if (prefix) {
		static const char *(matchbuf[2]);
		matchbuf[0] = prefix;
		matchbuf[1] = NULL;
		match = matchbuf;
	} else
		match = NULL;
	if (read_tree(tree, 1, match))
		die("unable to read tree entries %s", tree_name);

	for (i = 0; i < active_nr; i++) {
		struct cache_entry *ce = active_cache[i];
		switch (ce_stage(ce)) {
		case 0:
			last_stage0 = ce;
			/* fallthru */
		default:
			continue;
		case 1:
			/*
			 * If there is stage #0 entry for this, we do not
			 * need to show it.  We use CE_UPDATE bit to mark
			 * such an entry.
			 */
			if (last_stage0 &&
			    !strcmp(last_stage0->name, ce->name))
				ce->ce_flags |= CE_UPDATE;
		}
	}
}

static int reset_index(const unsigned char *sha1, int reset_type, int quiet)
{
	int nr = 1;
	struct tree_desc desc[2];
	struct tree *tree;
	struct unpack_trees_options opts;

	memset(&opts, 0, sizeof(opts));
	opts.head_idx = 1;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;
	opts.fn = oneway_merge;
	opts.merge = 1;
	if (!quiet)
		opts.verbose_update = 1;
	switch (reset_type) {
	case KEEP:
	case MERGE:
		opts.update = 1;
		break;
	case HARD:
		opts.update = 1;
		/* fallthrough */
	default:
		opts.reset = 1;
	}

	read_cache_unmerged();

	if (reset_type == KEEP) {
		unsigned char head_sha1[20];
		if (get_sha1("HEAD", head_sha1))
			return error(_("You do not have a valid HEAD."));
		if (!fill_tree_descriptor(desc, head_sha1))
			return error(_("Failed to find tree of HEAD."));
		nr++;
		opts.fn = twoway_merge;
	}

	if (!fill_tree_descriptor(desc + nr - 1, sha1))
		return error(_("Failed to find tree of %s."), sha1_to_hex(sha1));
	if (unpack_trees(nr, desc, &opts))
		return -1;

	if (reset_type == MIXED || reset_type == HARD) {
		tree = parse_tree_indirect(sha1);
		prime_cache_tree(&active_cache_tree, tree);
	}

	return 0;
}

static int do_recursive_merge(struct commit *base, struct commit *next,
			      const char *base_label, const char *next_label,
			      unsigned char *head, struct strbuf *msgbuf,
			      struct replay_opts *opts)
{
	struct merge_options o;
	struct tree *result, *next_tree, *base_tree, *head_tree;
	int clean;
	char **xopt;
	static struct lock_file index_lock;

	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);

	read_cache();

	init_merge_options(&o);
	o.ancestor = base ? base_label : "(empty tree)";
	o.branch1 = "HEAD";
	o.branch2 = next ? next_label : "(empty tree)";

	head_tree = parse_tree_indirect(head);
	next_tree = next ? next->tree : empty_tree();
	base_tree = base ? base->tree : empty_tree();

	for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
		parse_merge_opt(&o, *xopt);

	clean = merge_trees(&o,
			    head_tree,
			    next_tree, base_tree, &result);
	strbuf_release(&o.obuf);
	if (clean < 0)
		return clean;

	if (active_cache_changed &&
	    write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
		/* TRANSLATORS: %s will be "revert" or "cherry-pick" */
		return error(_("%s: Unable to write new index file"),
			_(action_name(opts)));
	rollback_lock_file(&index_lock);

	if (opts->signoff)
		append_signoff(msgbuf, 0, 0);

	if (!clean)
		append_conflicts_hint(msgbuf);

	return !clean;
}

int git_read_tree(GIT_HASH hash,read_tree_fn_t fn, void *context)
{
	struct tree * root;
	int ret;
	reprepare_packed_git();
	root = parse_tree_indirect(hash);

	if (!root)
	{
		free_all_pack();
		return -1;
	}
	ret = read_tree_recursive(root, NULL, 0, 0, NULL, fn, context);
	free_all_pack();
	return ret;
}

int git_checkout_file(const char* ref, const char* path, char* outputpath)
{
	struct cache_entry *ce;
	int ret;
	struct object_id oid;
	struct tree * root;
	struct checkout state;
	struct pathspec pathspec;
	const char *matchbuf[1];
	ret = get_oid(ref, &oid);
	if(ret)
		return ret;

	reprepare_packed_git(the_repository);
	root = parse_tree_indirect(&oid);

	if(!root)
	{
		free_all_pack();
		return -1;
	}

	ce = xcalloc(1, cache_entry_size(strlen(path)));

	matchbuf[0] = NULL;
	parse_pathspec(&pathspec, PATHSPEC_ALL_MAGIC, PATHSPEC_PREFER_CWD, path, matchbuf);
	pathspec.items[0].nowildcard_len = pathspec.items[0].len;
	ret = read_tree_recursive(root, "", 0, 0, &pathspec, update_some, ce);
	clear_pathspec(&pathspec);

	if(ret)
	{
		free_all_pack();
		free(ce);
		return ret;
	}
	memset(&state, 0, sizeof(state));
	state.force = 1;
	state.refresh_cache = 0;

	ret = write_entry(ce, outputpath, &state, 0);
	free_all_pack();
	free(ce);
	return ret;
}

static int reset_tree(struct object_id *i_tree, int update, int reset)
{
	int nr_trees = 1;
	struct unpack_trees_options opts;
	struct tree_desc t[MAX_UNPACK_TREES];
	struct tree *tree;
	struct lock_file lock_file = LOCK_INIT;

	read_cache_preload(NULL);
	if (refresh_cache(REFRESH_QUIET))
		return -1;

	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);

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

	tree = parse_tree_indirect(i_tree);
	if (parse_tree(tree))
		return -1;

	init_tree_desc(t, tree->buffer, tree->size);

	opts.head_idx = 1;
	opts.src_index = &the_index;
	opts.dst_index = &the_index;
	opts.merge = 1;
	opts.reset = reset;
	opts.update = update;
	opts.fn = oneway_merge;

	if (unpack_trees(nr_trees, t, &opts))
		return -1;

	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
		return error(_("unable to write new index file"));

	return 0;
}