static int commit_index_files(void)
{
	int err = 0;

	switch (commit_style) {
	case COMMIT_AS_IS:
		break; /* nothing to do */
	case COMMIT_NORMAL:
		err = commit_lock_file(&index_lock);
		break;
	case COMMIT_PARTIAL:
		err = commit_lock_file(&index_lock);
		rollback_lock_file(&false_lock);
		break;
	}

	return err;
}

static void update_paths(struct string_list *update)
{
	int i;

	hold_locked_index(&index_lock, 1);

	for (i = 0; i < update->nr; i++) {
		struct string_list_item *item = &update->items[i];
		if (add_file_to_cache(item->string, 0))
			exit(128);
	}

	if (active_cache_changed) {
		if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
			die("Unable to write new index file");
	} else
		rollback_lock_file(&index_lock);
}

static void refresh_index_quietly(void)
{
	struct lock_file *lock_file;
	int fd;

	lock_file = xcalloc(1, sizeof(struct lock_file));
	fd = hold_locked_index(lock_file, 0);
	if (fd < 0)
		return;
	discard_cache();
	read_cache();
	refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);

	if (active_cache_changed &&
	    !write_cache(fd, active_cache, active_nr))
		commit_locked_index(lock_file);

	rollback_lock_file(lock_file);
}

void rerere_gc(struct string_list *rr)
{
	struct string_list to_remove = STRING_LIST_INIT_DUP;
	DIR *dir;
	struct dirent *e;
	int i, cutoff;
	time_t now = time(NULL), then;
	int cutoff_noresolve = 15;
	int cutoff_resolve = 60;

	if (setup_rerere(rr, 0) < 0)
		return;

	git_config_get_int("gc.rerereresolved", &cutoff_resolve);
	git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);
	git_config(git_default_config, NULL);
	dir = opendir(git_path("rr-cache"));
	if (!dir)
		die_errno("unable to open rr-cache directory");
	/* Collect stale conflict IDs ... */
	while ((e = readdir(dir))) {
		if (is_dot_or_dotdot(e->d_name))
			continue;

		then = rerere_last_used_at(e->d_name);
		if (then) {
			cutoff = cutoff_resolve;
		} else {
			then = rerere_created_at(e->d_name);
			if (!then)
				continue;
			cutoff = cutoff_noresolve;
		}
		if (then < now - cutoff * 86400)
			string_list_append(&to_remove, e->d_name);
	}
	closedir(dir);
	/* ... and then remove them one-by-one */
	for (i = 0; i < to_remove.nr; i++)
		unlink_rr_item(dirname_to_id(to_remove.items[i].string));
	string_list_clear(&to_remove, 0);
	rollback_lock_file(&write_lock);
}

int commit_lock_file_to(struct lock_file *lk, const char *path)
{
	if (!lk->active)
		die("BUG: attempt to commit unlocked object to \"%s\"", path);

	if (close_lock_file(lk))
		return -1;

	if (rename(lk->filename.buf, path)) {
		int save_errno = errno;
		rollback_lock_file(lk);
		errno = save_errno;
		return -1;
	}

	lk->active = 0;
	strbuf_reset(&lk->filename);
	return 0;
}

static void update_paths(struct string_list *update)
{
	int i;

	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);

	for (i = 0; i < update->nr; i++) {
		struct string_list_item *item = &update->items[i];
		if (add_file_to_cache(item->string, 0))
			exit(128);
		fprintf(stderr, "Staged '%s' using previous resolution.\n",
			item->string);
	}

	if (active_cache_changed) {
		if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
			die("Unable to write new index file");
	} else
		rollback_lock_file(&index_lock);
}

static int update_paths(struct string_list *update)
{
	int i;
	int fd = hold_locked_index(&index_lock, 0);
	int status = 0;

	if (fd < 0)
		return -1;

	for (i = 0; i < update->nr; i++) {
		struct string_list_item *item = &update->items[i];
		if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
			status = -1;
	}

	if (!status && active_cache_changed) {
		if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
			die("Unable to write new index file");
	} else if (fd >= 0)
		rollback_lock_file(&index_lock);
	return status;
}

static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
{
	static struct lock_file shallow_lock;
	struct sha1_array extra = SHA1_ARRAY_INIT;
	const char *alt_file;
	uint32_t mask = 1 << (cmd->index % 32);
	int i;

	trace_printf_key(&trace_shallow,
			 "shallow: update_shallow_ref %s\n", cmd->ref_name);
	for (i = 0; i < si->shallow->nr; i++)
		if (si->used_shallow[i] &&
		    (si->used_shallow[i][cmd->index / 32] & mask) &&
		    !delayed_reachability_test(si, i))
			sha1_array_append(&extra, si->shallow->sha1[i]);

	setup_alternate_shallow(&shallow_lock, &alt_file, &extra);
	if (check_shallow_connected(command_singleton_iterator,
				    0, cmd, alt_file)) {
		rollback_lock_file(&shallow_lock);
		sha1_array_clear(&extra);
		return -1;
	}

	commit_lock_file(&shallow_lock);

	/*
	 * Make sure setup_alternate_shallow() for the next ref does
	 * not lose these new roots..
	 */
	for (i = 0; i < extra.nr; i++)
		register_shallow(extra.sha1[i]);

	si->shallow_ref[cmd->index] = 0;
	sha1_array_clear(&extra);
	return 0;
}

static int try_merge_strategy(const char *strategy, struct commit_list *common,
			      const char *head_arg)
{
	const char **args;
	int i = 0, ret;
	struct commit_list *j;
	struct strbuf buf = STRBUF_INIT;
	int index_fd;
	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));

	index_fd = hold_locked_index(lock, 1);
	refresh_cache(REFRESH_QUIET);
	if (active_cache_changed &&
			(write_cache(index_fd, active_cache, active_nr) ||
			 commit_locked_index(lock)))
		return error("Unable to write index.");
	rollback_lock_file(lock);

	if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
		int clean;
		struct commit *result;
		struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
		int index_fd;
		struct commit_list *reversed = NULL;
		struct merge_options o;

		if (remoteheads->next) {
			error("Not handling anything other than two heads merge.");
			return 2;
		}

		init_merge_options(&o);
		if (!strcmp(strategy, "subtree"))
			o.subtree_merge = 1;

		o.branch1 = head_arg;
		o.branch2 = remoteheads->item->util;

		for (j = common; j; j = j->next)
			commit_list_insert(j->item, &reversed);

		index_fd = hold_locked_index(lock, 1);
		clean = merge_recursive(&o, lookup_commit(head),
				remoteheads->item, reversed, &result);
		if (active_cache_changed &&
				(write_cache(index_fd, active_cache, active_nr) ||
				 commit_locked_index(lock)))
			die ("unable to write %s", get_index_file());
		rollback_lock_file(lock);
		return clean ? 0 : 1;
	} else {
		args = xmalloc((4 + commit_list_count(common) +
					commit_list_count(remoteheads)) * sizeof(char *));
		strbuf_addf(&buf, "merge-%s", strategy);
		args[i++] = buf.buf;
		for (j = common; j; j = j->next)
			args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
		args[i++] = "--";
		args[i++] = head_arg;
		for (j = remoteheads; j; j = j->next)
			args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
		args[i] = NULL;
		ret = run_command_v_opt(args, RUN_GIT_CMD);
		strbuf_release(&buf);
		i = 1;
		for (j = common; j; j = j->next)
			free((void *)args[i++]);
		i += 2;
		for (j = remoteheads; j; j = j->next)
			free((void *)args[i++]);
		free(args);
		discard_cache();
		if (read_cache() < 0)
			die("failed to read the cache");
		return ret;
	}
}

struct ref *fetch_pack(struct fetch_pack_args *args,
		       int fd[], struct child_process *conn,
		       const struct ref *ref,
		       const char *dest,
		       struct string_list *sought,
		       char **pack_lockfile)
{
	struct stat st;
	struct ref *ref_cpy;

	fetch_pack_setup();
	if (args->depth > 0) {
		if (stat(git_path("shallow"), &st))
			st.st_mtime = 0;
	}

	if (sought->nr) {
		sort_string_list(sought);
		string_list_remove_duplicates(sought, 0);
	}

	if (!ref) {
		packet_flush(fd[1]);
		die("no matching remote head");
	}
	ref_cpy = do_fetch_pack(args, fd, ref, sought, pack_lockfile);

	if (args->depth > 0) {
		static struct lock_file lock;
		struct cache_time mtime;
		struct strbuf sb = STRBUF_INIT;
		char *shallow = git_path("shallow");
		int fd;

		mtime.sec = st.st_mtime;
		mtime.nsec = ST_MTIME_NSEC(st);
		if (stat(shallow, &st)) {
			if (mtime.sec)
				die("shallow file was removed during fetch");
		} else if (st.st_mtime != mtime.sec
#ifdef USE_NSEC
				|| ST_MTIME_NSEC(st) != mtime.nsec
#endif
			  )
			die("shallow file was changed during fetch");

		fd = hold_lock_file_for_update(&lock, shallow,
					       LOCK_DIE_ON_ERROR);
		if (!write_shallow_commits(&sb, 0)
		 || write_in_full(fd, sb.buf, sb.len) != sb.len) {
			unlink_or_warn(shallow);
			rollback_lock_file(&lock);
		} else {
			commit_lock_file(&lock);
		}
		strbuf_release(&sb);
	}

	reprepare_packed_git();
	return ref_cpy;
}

struct ref *fetch_pack(struct fetch_pack_args *args,
		       int fd[], struct child_process *conn,
		       const struct ref *ref,
		       const char *dest,
		       struct ref **sought, int nr_sought,
		       struct oid_array *shallow,
		       char **pack_lockfile,
		       enum protocol_version version)
{
	struct ref *ref_cpy;
	struct shallow_info si;

	fetch_pack_setup();
	if (nr_sought)
		nr_sought = remove_duplicates_in_refs(sought, nr_sought);

	if (args->no_dependents && !args->filter_options.choice) {
		/*
		 * The protocol does not support requesting that only the
		 * wanted objects be sent, so approximate this by setting a
		 * "blob:none" filter if no filter is already set. This works
		 * for all object types: note that wanted blobs will still be
		 * sent because they are directly specified as a "want".
		 *
		 * NEEDSWORK: Add an option in the protocol to request that
		 * only the wanted objects be sent, and implement it.
		 */
		parse_list_objects_filter(&args->filter_options, "blob:none");
	}

	if (version != protocol_v2 && !ref) {
		packet_flush(fd[1]);
		die(_("no matching remote head"));
	}
	prepare_shallow_info(&si, shallow);
	if (version == protocol_v2)
		ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
					   pack_lockfile);
	else
		ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
					&si, pack_lockfile);
	reprepare_packed_git(the_repository);

	if (!args->cloning && args->deepen) {
		struct check_connected_options opt = CHECK_CONNECTED_INIT;
		struct ref *iterator = ref_cpy;
		opt.shallow_file = alternate_shallow_file;
		if (args->deepen)
			opt.is_deepening_fetch = 1;
		if (check_connected(iterate_ref_map, &iterator, &opt)) {
			error(_("remote did not send all necessary objects"));
			free_refs(ref_cpy);
			ref_cpy = NULL;
			rollback_lock_file(&shallow_lock);
			goto cleanup;
		}
		args->connectivity_checked = 1;
	}

	update_shallow(args, sought, nr_sought, &si);
cleanup:
	clear_shallow_info(&si);
	return ref_cpy;
}

//.........这里部分代码省略.........
		the_index.version = preferred_index_format;
	}

	if (read_from_stdin) {
		struct strbuf buf = STRBUF_INIT;
		struct strbuf unquoted = STRBUF_INIT;

		setup_work_tree();
		while (getline_fn(&buf, stdin) != EOF) {
			char *p;
			if (!nul_term_line && buf.buf[0] == '"') {
				strbuf_reset(&unquoted);
				if (unquote_c_style(&unquoted, buf.buf, NULL))
					die("line is badly quoted");
				strbuf_swap(&buf, &unquoted);
			}
			p = prefix_path(prefix, prefix_length, buf.buf);
			update_one(p);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			free(p);
		}
		strbuf_release(&unquoted);
		strbuf_release(&buf);
	}

	if (split_index > 0) {
		if (git_config_get_split_index() == 0)
			warning(_("core.splitIndex is set to false; "
				  "remove or change it, if you really want to "
				  "enable split index"));
		if (the_index.split_index)
			the_index.cache_changed |= SPLIT_INDEX_ORDERED;
		else
			add_split_index(&the_index);
	} else if (!split_index) {
		if (git_config_get_split_index() == 1)
			warning(_("core.splitIndex is set to true; "
				  "remove or change it, if you really want to "
				  "disable split index"));
		remove_split_index(&the_index);
	}

	switch (untracked_cache) {
	case UC_UNSPECIFIED:
		break;
	case UC_DISABLE:
		if (git_config_get_untracked_cache() == 1)
			warning(_("core.untrackedCache is set to true; "
				  "remove or change it, if you really want to "
				  "disable the untracked cache"));
		remove_untracked_cache(&the_index);
		report(_("Untracked cache disabled"));
		break;
	case UC_TEST:
		setup_work_tree();
		return !test_if_untracked_cache_is_supported();
	case UC_ENABLE:
	case UC_FORCE:
		if (git_config_get_untracked_cache() == 0)
			warning(_("core.untrackedCache is set to false; "
				  "remove or change it, if you really want to "
				  "enable the untracked cache"));
		add_untracked_cache(&the_index);
		report(_("Untracked cache enabled for '%s'"), get_git_work_tree());
		break;
	default:
		BUG("bad untracked_cache value: %d", untracked_cache);
	}

	if (fsmonitor > 0) {
		if (git_config_get_fsmonitor() == 0)
			warning(_("core.fsmonitor is unset; "
				"set it if you really want to "
				"enable fsmonitor"));
		add_fsmonitor(&the_index);
		report(_("fsmonitor enabled"));
	} else if (!fsmonitor) {
		if (git_config_get_fsmonitor() == 1)
			warning(_("core.fsmonitor is set; "
				"remove it if you really want to "
				"disable fsmonitor"));
		remove_fsmonitor(&the_index);
		report(_("fsmonitor disabled"));
	}

	if (active_cache_changed || force_write) {
		if (newfd < 0) {
			if (refresh_args.flags & REFRESH_QUIET)
				exit(128);
			unable_to_lock_die(get_index_file(), lock_error);
		}
		if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
			die("Unable to write new index file");
	}

	rollback_lock_file(&lock_file);

	return has_errors ? 1 : 0;
}

static char *prepare_index(int argc, const char **argv, const char *prefix,
			   const struct commit *current_head, int is_status)
{
	int fd;
	struct string_list partial;
	struct pathspec pathspec;
	int refresh_flags = REFRESH_QUIET;

	if (is_status)
		refresh_flags |= REFRESH_UNMERGED;
	parse_pathspec(&pathspec, 0,
		       PATHSPEC_PREFER_FULL,
		       prefix, argv);

	if (read_cache_preload(&pathspec) < 0)
		die(_("index file corrupt"));

	if (interactive) {
		char *old_index_env = NULL;
		fd = hold_locked_index(&index_lock, 1);

		refresh_cache_or_die(refresh_flags);

		if (write_cache(fd, active_cache, active_nr) ||
		    close_lock_file(&index_lock))
			die(_("unable to create temporary index"));

		old_index_env = getenv(INDEX_ENVIRONMENT);
		setenv(INDEX_ENVIRONMENT, index_lock.filename, 1);

		if (interactive_add(argc, argv, prefix, patch_interactive) != 0)
			die(_("interactive add failed"));

		if (old_index_env && *old_index_env)
			setenv(INDEX_ENVIRONMENT, old_index_env, 1);
		else
			unsetenv(INDEX_ENVIRONMENT);

		discard_cache();
		read_cache_from(index_lock.filename);

		commit_style = COMMIT_NORMAL;
		return index_lock.filename;
	}

	/*
	 * Non partial, non as-is commit.
	 *
	 * (1) get the real index;
	 * (2) update the_index as necessary;
	 * (3) write the_index out to the real index (still locked);
	 * (4) return the name of the locked index file.
	 *
	 * The caller should run hooks on the locked real index, and
	 * (A) if all goes well, commit the real index;
	 * (B) on failure, rollback the real index.
	 */
	if (all || (also && pathspec.nr)) {
		fd = hold_locked_index(&index_lock, 1);
		add_files_to_cache(also ? prefix : NULL, &pathspec, 0);
		refresh_cache_or_die(refresh_flags);
		update_main_cache_tree(WRITE_TREE_SILENT);
		if (write_cache(fd, active_cache, active_nr) ||
		    close_lock_file(&index_lock))
			die(_("unable to write new_index file"));
		commit_style = COMMIT_NORMAL;
		return index_lock.filename;
	}

	/*
	 * As-is commit.
	 *
	 * (1) return the name of the real index file.
	 *
	 * The caller should run hooks on the real index,
	 * and create commit from the_index.
	 * We still need to refresh the index here.
	 */
	if (!only && !pathspec.nr) {
		fd = hold_locked_index(&index_lock, 1);
		refresh_cache_or_die(refresh_flags);
		if (active_cache_changed) {
			update_main_cache_tree(WRITE_TREE_SILENT);
			if (write_cache(fd, active_cache, active_nr) ||
			    commit_locked_index(&index_lock))
				die(_("unable to write new_index file"));
		} else {
			rollback_lock_file(&index_lock);
		}
		commit_style = COMMIT_AS_IS;
		return get_index_file();
	}

	/*
	 * A partial commit.
	 *
	 * (0) find the set of affected paths;
	 * (1) get lock on the real index file;
	 * (2) update the_index with the given paths;
	 * (3) write the_index out to the real index (still locked);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
				free(store.value_regex);
			}
			ret = CONFIG_INVALID_FILE;
			goto out_free;
		}

		free(store.key);
		if (store.value_regex != NULL) {
			regfree(store.value_regex);
			free(store.value_regex);
		}

		/* if nothing to unset, or too many matches, error out */
		if ((store.seen == 0 && value == NULL) ||
				(store.seen > 1 && multi_replace == 0)) {
			ret = CONFIG_NOTHING_SET;
			goto out_free;
		}

		fstat(in_fd, &st);
		contents_sz = xsize_t(st.st_size);
		contents = xmmap(NULL, contents_sz, PROT_READ,
			MAP_PRIVATE, in_fd, 0);
		close(in_fd);

		if (store.seen == 0)
			store.seen = 1;

		for (i = 0, copy_begin = 0; i < store.seen; i++) {
			if (store.offset[i] == 0) {
				store.offset[i] = copy_end = contents_sz;
			} else if (store.state != KEY_SEEN) {
				copy_end = store.offset[i];
			} else
				copy_end = find_beginning_of_line(
					contents, contents_sz,
					store.offset[i]-2, &new_line);

			if (copy_end > 0 && contents[copy_end-1] != '\n')
				new_line = 1;

			/* write the first part of the config */
			if (copy_end > copy_begin) {
				if (write_in_full(fd, contents + copy_begin,
						  copy_end - copy_begin) <
				    copy_end - copy_begin)
					goto write_err_out;
				if (new_line &&
				    write_str_in_full(fd, "\n") != 1)
					goto write_err_out;
			}
			copy_begin = store.offset[i];
		}

		/* write the pair (value == NULL means unset) */
		if (value != NULL) {
			if (store.state == START) {
				if (!store_write_section(fd, key))
					goto write_err_out;
			}
			if (!store_write_pair(fd, key, value))
				goto write_err_out;
		}

		/* write the rest of the config */
		if (copy_begin < contents_sz)
			if (write_in_full(fd, contents + copy_begin,
					  contents_sz - copy_begin) <
			    contents_sz - copy_begin)
				goto write_err_out;

		munmap(contents, contents_sz);
	}

	if (commit_lock_file(lock) < 0) {
		error("could not commit config file %s", config_filename);
		ret = CONFIG_NO_WRITE;
		goto out_free;
	}

	/*
	 * lock is committed, so don't try to roll it back below.
	 * NOTE: Since lockfile.c keeps a linked list of all created
	 * lock_file structures, it isn't safe to free(lock).  It's
	 * better to just leave it hanging around.
	 */
	lock = NULL;
	ret = 0;

out_free:
	if (lock)
		rollback_lock_file(lock);
	free(config_filename);
	return ret;

write_err_out:
	ret = write_error(lock->filename);
	goto out_free;

}

//.........这里部分代码省略.........
			ensure_leading_directories(rdir.buf);
			write_file(rdir.buf, "%s", entry->right);
		}
	}

	strbuf_release(&buf);

	strbuf_setlen(&ldir, ldir_len);
	helper_argv[1] = ldir.buf;
	strbuf_setlen(&rdir, rdir_len);
	helper_argv[2] = rdir.buf;

	if (extcmd) {
		helper_argv[0] = extcmd;
		flags = 0;
	} else
		setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
	rc = run_command_v_opt(helper_argv, flags);

	/*
	 * If the diff includes working copy files and those
	 * files were modified during the diff, then the changes
	 * should be copied back to the working tree.
	 * Do not copy back files when symlinks are used and the
	 * external tool did not replace the original link with a file.
	 *
	 * These hashes are loaded lazily since they aren't needed
	 * in the common case of --symlinks and the difftool updating
	 * files through the symlink.
	 */
	hashmap_init(&wt_modified, (hashmap_cmp_fn)path_entry_cmp,
		     NULL, wtindex.cache_nr);
	hashmap_init(&tmp_modified, (hashmap_cmp_fn)path_entry_cmp,
		     NULL, wtindex.cache_nr);

	for (i = 0; i < wtindex.cache_nr; i++) {
		struct hashmap_entry dummy;
		const char *name = wtindex.cache[i]->name;
		struct stat st;

		add_path(&rdir, rdir_len, name);
		if (lstat(rdir.buf, &st))
			continue;

		if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
			continue;

		if (!indices_loaded) {
			static struct lock_file lock;
			strbuf_reset(&buf);
			strbuf_addf(&buf, "%s/wtindex", tmpdir);
			if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
			    write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
				ret = error("could not write %s", buf.buf);
				rollback_lock_file(&lock);
				goto finish;
			}
			changed_files(&wt_modified, buf.buf, workdir);
			strbuf_setlen(&rdir, rdir_len);
			changed_files(&tmp_modified, buf.buf, rdir.buf);
			add_path(&rdir, rdir_len, name);
			indices_loaded = 1;
		}

		hashmap_entry_init(&dummy, strhash(name));
		if (hashmap_get(&tmp_modified, &dummy, name)) {
			add_path(&wtdir, wtdir_len, name);
			if (hashmap_get(&wt_modified, &dummy, name)) {
				warning(_("both files modified: '%s' and '%s'."),
					wtdir.buf, rdir.buf);
				warning(_("working tree file has been left."));
				warning("%s", "");
				err = 1;
			} else if (unlink(wtdir.buf) ||
				   copy_file(wtdir.buf, rdir.buf, st.st_mode))
				warning_errno(_("could not copy '%s' to '%s'"),
					      rdir.buf, wtdir.buf);
		}
	}

	if (err) {
		warning(_("temporary files exist in '%s'."), tmpdir);
		warning(_("you may want to cleanup or recover these."));
		exit(1);
	} else
		exit_cleanup(tmpdir, rc);

finish:
	if (fp)
		fclose(fp);

	free(lbase_dir);
	free(rbase_dir);
	strbuf_release(&ldir);
	strbuf_release(&rdir);
	strbuf_release(&wtdir);
	strbuf_release(&buf);

	return ret;
}

static int try_merge_strategy(const char *strategy, struct commit_list *common,
			      struct commit_list *remoteheads,
			      struct commit *head, const char *head_arg)
{
	int index_fd;
	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));

	index_fd = hold_locked_index(lock, 1);
	refresh_cache(REFRESH_QUIET);
	if (active_cache_changed &&
			(write_cache(index_fd, active_cache, active_nr) ||
			 commit_locked_index(lock)))
		return error(_("Unable to write index."));
	rollback_lock_file(lock);

	if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
		int clean, x;
		struct commit *result;
		struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
		int index_fd;
		struct commit_list *reversed = NULL;
		struct merge_options o;
		struct commit_list *j;

		if (remoteheads->next) {
			error(_("Not handling anything other than two heads merge."));
			return 2;
		}

		init_merge_options(&o);
		if (!strcmp(strategy, "subtree"))
			o.subtree_shift = "";

		o.renormalize = option_renormalize;
		o.show_rename_progress =
			show_progress == -1 ? isatty(2) : show_progress;

		for (x = 0; x < xopts_nr; x++)
			if (parse_merge_opt(&o, xopts[x]))
				die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);

		o.branch1 = head_arg;
		o.branch2 = merge_remote_util(remoteheads->item)->name;

		for (j = common; j; j = j->next)
			commit_list_insert(j->item, &reversed);

		index_fd = hold_locked_index(lock, 1);
		clean = merge_recursive(&o, head,
				remoteheads->item, reversed, &result);
		if (active_cache_changed &&
				(write_cache(index_fd, active_cache, active_nr) ||
				 commit_locked_index(lock)))
			die (_("unable to write %s"), get_index_file());
		rollback_lock_file(lock);
		return clean ? 0 : 1;
	} else {
		return try_merge_command(strategy, xopts_nr, xopts,
						common, head_arg, remoteheads);
	}
}

int cmd_status(int argc, const char **argv, const char *prefix)
{
	struct wt_status s;
	int fd;
	unsigned char sha1[20];
	static struct option builtin_status_options[] = {
		OPT__VERBOSE(&verbose, "be verbose"),
		OPT_SET_INT('s', "short", &status_format,
			    "show status concisely", STATUS_FORMAT_SHORT),
		OPT_BOOLEAN('b', "branch", &status_show_branch,
			    "show branch information"),
		OPT_SET_INT(0, "porcelain", &status_format,
			    "show porcelain output format",
			    STATUS_FORMAT_PORCELAIN),
		OPT_BOOLEAN('z', "null", &null_termination,
			    "terminate entries with NUL"),
		{ OPTION_STRING, 'u', "untracked-files", &untracked_files_arg,
		  "mode",
		  "show untracked files, optional modes: all, normal, no. (Default: all)",
		  PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
		OPT_BOOLEAN(0, "ignored", &show_ignored_in_status,
			    "show ignored files"),
		{ OPTION_STRING, 0, "ignore-submodules", &ignore_submodule_arg, "when",
		  "ignore changes to submodules, optional when: all, dirty, untracked. (Default: all)",
		  PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
		OPT_END(),
	};

	if (null_termination && status_format == STATUS_FORMAT_LONG)
		status_format = STATUS_FORMAT_PORCELAIN;

	wt_status_prepare(&s);
	gitmodules_config();
	git_config(git_status_config, &s);
	in_merge = file_exists(git_path("MERGE_HEAD"));
	argc = parse_options(argc, argv, prefix,
			     builtin_status_options,
			     builtin_status_usage, 0);
	handle_untracked_files_arg(&s);
	if (show_ignored_in_status)
		s.show_ignored_files = 1;
	if (*argv)
		s.pathspec = get_pathspec(prefix, argv);

	read_cache_preload(s.pathspec);
	refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, s.pathspec, NULL, NULL);

	fd = hold_locked_index(&index_lock, 0);
	if (0 <= fd) {
		if (active_cache_changed &&
		    !write_cache(fd, active_cache, active_nr))
			commit_locked_index(&index_lock);
		else
			rollback_lock_file(&index_lock);
	}

	s.is_initial = get_sha1(s.reference, sha1) ? 1 : 0;
	s.in_merge = in_merge;
	s.ignore_submodule_arg = ignore_submodule_arg;
	wt_status_collect(&s);

	if (s.relative_paths)
		s.prefix = prefix;
	if (s.use_color == -1)
		s.use_color = git_use_color_default;
	if (diff_use_color_default == -1)
		diff_use_color_default = git_use_color_default;

	switch (status_format) {
	case STATUS_FORMAT_SHORT:
		wt_shortstatus_print(&s, null_termination, status_show_branch);
		break;
	case STATUS_FORMAT_PORCELAIN:
		wt_porcelain_print(&s, null_termination);
		break;
	case STATUS_FORMAT_LONG:
		s.verbose = verbose;
		s.ignore_submodule_arg = ignore_submodule_arg;
		wt_status_print(&s);
		break;
	}
	return 0;
}

//.........这里部分代码省略.........
			}
			if (!strcmp(path, "--info-only")) {
				info_only = 1;
				continue;
			}
			if (!strcmp(path, "--force-remove")) {
				force_remove = 1;
				continue;
			}
			if (!strcmp(path, "-z")) {
				line_termination = 0;
				continue;
			}
			if (!strcmp(path, "--stdin")) {
				if (i != argc - 1)
					die("--stdin must be at the end");
				read_from_stdin = 1;
				break;
			}
			if (!strcmp(path, "--index-info")) {
				if (i != argc - 1)
					die("--index-info must be at the end");
				allow_add = allow_replace = allow_remove = 1;
				read_index_info(line_termination);
				break;
			}
			if (!strcmp(path, "--unresolve")) {
				has_errors = do_unresolve(argc - i, argv + i,
							  prefix, prefix_length);
				if (has_errors)
					active_cache_changed = 0;
				goto finish;
			}
			if (!strcmp(path, "--again") || !strcmp(path, "-g")) {
				setup_work_tree();
				has_errors = do_reupdate(argc - i, argv + i,
							 prefix, prefix_length);
				if (has_errors)
					active_cache_changed = 0;
				goto finish;
			}
			if (!strcmp(path, "--ignore-missing")) {
				refresh_flags |= REFRESH_IGNORE_MISSING;
				continue;
			}
			if (!strcmp(path, "--verbose")) {
				verbose = 1;
				continue;
			}
			if (!strcmp(path, "-h") || !strcmp(path, "--help"))
				usage(update_index_usage);
			die("unknown option %s", path);
		}
		setup_work_tree();
		p = prefix_path(prefix, prefix_length, path);
		update_one(p, NULL, 0);
		if (set_executable_bit)
			chmod_path(set_executable_bit, p);
		if (p < path || p > path + strlen(path))
			free((char*)p);
	}
	if (read_from_stdin) {
		struct strbuf buf = STRBUF_INIT, nbuf = STRBUF_INIT;

		setup_work_tree();
		while (strbuf_getline(&buf, stdin, line_termination) != EOF) {
			const char *p;
			if (line_termination && buf.buf[0] == '"') {
				strbuf_reset(&nbuf);
				if (unquote_c_style(&nbuf, buf.buf, NULL))
					die("line is badly quoted");
				strbuf_swap(&buf, &nbuf);
			}
			p = prefix_path(prefix, prefix_length, buf.buf);
			update_one(p, NULL, 0);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			if (p < buf.buf || p > buf.buf + buf.len)
				free((char *)p);
		}
		strbuf_release(&nbuf);
		strbuf_release(&buf);
	}

 finish:
	if (active_cache_changed) {
		if (newfd < 0) {
			if (refresh_flags & REFRESH_QUIET)
				exit(128);
			unable_to_lock_index_die(get_index_file(), lock_error);
		}
		if (write_cache(newfd, active_cache, active_nr) ||
		    commit_locked_index(lock_file))
			die("Unable to write new index file");
	}

	rollback_lock_file(lock_file);

	return has_errors ? 1 : 0;
}

static char *prepare_index(int argc, const char **argv, const char *prefix, int is_status)
{
	int fd;
	struct string_list partial;
	const char **pathspec = NULL;
	int refresh_flags = REFRESH_QUIET;

	if (is_status)
		refresh_flags |= REFRESH_UNMERGED;
	if (interactive) {
		if (interactive_add(argc, argv, prefix) != 0)
			die("interactive add failed");
		if (read_cache_preload(NULL) < 0)
			die("index file corrupt");
		commit_style = COMMIT_AS_IS;
		return get_index_file();
	}

	if (*argv)
		pathspec = get_pathspec(prefix, argv);

	if (read_cache_preload(pathspec) < 0)
		die("index file corrupt");

	/*
	 * Non partial, non as-is commit.
	 *
	 * (1) get the real index;
	 * (2) update the_index as necessary;
	 * (3) write the_index out to the real index (still locked);
	 * (4) return the name of the locked index file.
	 *
	 * The caller should run hooks on the locked real index, and
	 * (A) if all goes well, commit the real index;
	 * (B) on failure, rollback the real index.
	 */
	if (all || (also && pathspec && *pathspec)) {
		fd = hold_locked_index(&index_lock, 1);
		add_files_to_cache(also ? prefix : NULL, pathspec, 0);
		refresh_cache_or_die(refresh_flags);
		if (write_cache(fd, active_cache, active_nr) ||
		    close_lock_file(&index_lock))
			die("unable to write new_index file");
		commit_style = COMMIT_NORMAL;
		return index_lock.filename;
	}

	/*
	 * As-is commit.
	 *
	 * (1) return the name of the real index file.
	 *
	 * The caller should run hooks on the real index,
	 * and create commit from the_index.
	 * We still need to refresh the index here.
	 */
	if (!pathspec || !*pathspec) {
		fd = hold_locked_index(&index_lock, 1);
		refresh_cache_or_die(refresh_flags);
		if (active_cache_changed) {
			if (write_cache(fd, active_cache, active_nr) ||
			    commit_locked_index(&index_lock))
				die("unable to write new_index file");
		} else {
			rollback_lock_file(&index_lock);
		}
		commit_style = COMMIT_AS_IS;
		return get_index_file();
	}

	/*
	 * A partial commit.
	 *
	 * (0) find the set of affected paths;
	 * (1) get lock on the real index file;
	 * (2) update the_index with the given paths;
	 * (3) write the_index out to the real index (still locked);
	 * (4) get lock on the false index file;
	 * (5) reset the_index from HEAD;
	 * (6) update the_index the same way as (2);
	 * (7) write the_index out to the false index file;
	 * (8) return the name of the false index file (still locked);
	 *
	 * The caller should run hooks on the locked false index, and
	 * create commit from it.  Then
	 * (A) if all goes well, commit the real index;
	 * (B) on failure, rollback the real index;
	 * In either case, rollback the false index.
	 */
	commit_style = COMMIT_PARTIAL;

	if (in_merge)
		die("cannot do a partial commit during a merge.");

	memset(&partial, 0, sizeof(partial));
	partial.strdup_strings = 1;
	if (list_paths(&partial, initial_commit ? NULL : "HEAD", prefix, pathspec))
		exit(1);

	discard_cache();
//.........这里部分代码省略.........

//.........这里部分代码省略.........
	 * filename arguments as they come.
	 */
	parse_options_start(&ctx, argc, argv, prefix,
			    options, PARSE_OPT_STOP_AT_NON_OPTION);
	while (ctx.argc) {
		if (parseopt_state != PARSE_OPT_DONE)
			parseopt_state = parse_options_step(&ctx, options,
							    update_index_usage);
		if (!ctx.argc)
			break;
		switch (parseopt_state) {
		case PARSE_OPT_HELP:
			exit(129);
		case PARSE_OPT_NON_OPTION:
		case PARSE_OPT_DONE:
		{
			const char *path = ctx.argv[0];
			const char *p;

			setup_work_tree();
			p = prefix_path(prefix, prefix_length, path);
			update_one(p);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			free((char *)p);
			ctx.argc--;
			ctx.argv++;
			break;
		}
		case PARSE_OPT_UNKNOWN:
			if (ctx.argv[0][1] == '-')
				error("unknown option '%s'", ctx.argv[0] + 2);
			else
				error("unknown switch '%c'", *ctx.opt);
			usage_with_options(update_index_usage, options);
		}
	}
	argc = parse_options_end(&ctx);
	if (preferred_index_format) {
		if (preferred_index_format < INDEX_FORMAT_LB ||
		    INDEX_FORMAT_UB < preferred_index_format)
			die("index-version %d not in range: %d..%d",
			    preferred_index_format,
			    INDEX_FORMAT_LB, INDEX_FORMAT_UB);

		if (the_index.version != preferred_index_format)
			active_cache_changed |= SOMETHING_CHANGED;
		the_index.version = preferred_index_format;
	}

	if (read_from_stdin) {
		struct strbuf buf = STRBUF_INIT, nbuf = STRBUF_INIT;

		setup_work_tree();
		while (strbuf_getline(&buf, stdin, line_termination) != EOF) {
			const char *p;
			if (line_termination && buf.buf[0] == '"') {
				strbuf_reset(&nbuf);
				if (unquote_c_style(&nbuf, buf.buf, NULL))
					die("line is badly quoted");
				strbuf_swap(&buf, &nbuf);
			}
			p = prefix_path(prefix, prefix_length, buf.buf);
			update_one(p);
			if (set_executable_bit)
				chmod_path(set_executable_bit, p);
			free((char *)p);
		}
		strbuf_release(&nbuf);
		strbuf_release(&buf);
	}

	if (split_index > 0) {
		init_split_index(&the_index);
		the_index.cache_changed |= SPLIT_INDEX_ORDERED;
	} else if (!split_index && the_index.split_index) {
		/*
		 * can't discard_split_index(&the_index); because that
		 * will destroy split_index->base->cache[], which may
		 * be shared with the_index.cache[]. So yeah we're
		 * leaking a bit here.
		 */
		the_index.split_index = NULL;
		the_index.cache_changed |= SOMETHING_CHANGED;
	}

	if (active_cache_changed) {
		if (newfd < 0) {
			if (refresh_args.flags & REFRESH_QUIET)
				exit(128);
			unable_to_lock_die(get_index_file(), lock_error);
		}
		if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
			die("Unable to write new index file");
	}

	rollback_lock_file(lock_file);

	return has_errors ? 1 : 0;
}