You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: basicfs_windows.go
    path of file: ./repos/syncthing/lib/fs
    
    the code of the file until where you have to start completion: // Copyright (C) 2014 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.

//go:build windows
// +build windows

package fs

import (
	"bytes"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"syscall"
	"uns
    
func (f *BasicFilesystem) Lchown(name, uid, gid string) error {
	name, err := f.rooted(name)
	if err != nil {
		return err
	}

	hdl, err := windows.Open(name, windows.O_WRONLY, 0)
	if err != nil {
		return err
	}
	defer windows.Close(hdl)

	// Depending on whether we got an uid or a gid, we need to set the
	// appropriate flag and parse the corresponding SID. The one we're not
	// setting remains nil, which is what we want in the call to
	// SetSecurityInfo.

	var si windows.SECURITY_INFORMATION
	var ownerSID, groupSID *syscall.SID
	if uid != "" {
		ownerSID, err = syscall.StringToSid(uid)
		if err == nil {
			si |= windows.OWNER_SECURITY_INFORMATION
		}
	} else if gid != "" {
		groupSID, err = syscall.StringToSid(uid)
		if err == nil {
			si |= windows.GROUP_SECURITY_INFORMATION
		}
	} else {
		return errors.New("neither uid nor gid specified")
	}

	return windows.SetSecurityInfo(hdl, windows.SE_FILE_OBJECT, si, (*windows.SID)(ownerSID), (*windows.SID)(groupSID), nil, nil)
}