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: url_windows.go
    path of file: ./repos/gccrs/libgo/go/cmd/go/internal/web
    
    the code of the file until where you have to start completion: // Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package web

import (
	"errors"
	"path/filepath"
	"strings"
)

func convertFileURLPath(host, path string) (string, error) {
	if len(path) == 0 || path[0] != '/' {
		return "", errNotAbsolute
	}

	path = filepath.FromSlash(path)

	// We interpret Windows file URLs per the description in
	// https://blogs.msdn.microsoft.com/ie/2006/12/06/file-uris-in-windows/.

	// The host part of a file URL (if any) is the UNC volume name,
	// but RFC 8089 reserves the authority "localhost" for the local machine.
	if host != "" && host != "localhost" {
		// A common "legacy" format omits the leading slash before a drive letter,
		// encoding the drive letter as the host instead of part of the path.
		// (See https://blogs.msdn.microsoft.com/freeassociations/2005/05/19/the-bizarre-and-unhappy-story-of-file-urls/.)
		// We do not support that format, but we should at least emit a more
		// helpful error message for it.
		if filepath.VolumeName(host) != "" {
			return "", errors.New("file URL encodes volume in
    
func convertFileURLPath(host, path string) (string, error) {
	if len(path) == 0 || path[0] != '/' {
		return "", errNotAbsolute
	}

	path = filepath.FromSlash(path)

	// We interpret Windows file URLs per the description in
	// https://blogs.msdn.microsoft.com/ie/2006/12/06/file-uris-in-windows/.

	// The host part of a file URL (if any) is the UNC volume name,
	// but RFC 8089 reserves the authority "localhost" for the local machine.
	if host != "" && host != "localhost" {
		// A common "legacy" format omits the leading slash before a drive letter,
		// encoding the drive letter as the host instead of part of the path.
		// (See https://blogs.msdn.microsoft.com/freeassociations/2005/05/19/the-bizarre-and-unhappy-story-of-file-urls/.)
		// We do not support that format, but we should at least emit a more
		// helpful error message for it.
		if filepath.VolumeName(host) != "" {
			return "", errors.New("file URL encodes volume in host field: too few slashes?")
		}
		return `\\` + host + path, nil
	}

	// If host is empty, path must contain an initial slash followed by a
	// drive letter and path. Remove the slash and verify that the path is valid.
	if vol := filepath.VolumeName(path[1:]); vol == "" || strings.HasPrefix(vol, `\\`) {
		return "", errors.New("file URL missing drive letter")
	}
	return path[1:], nil
}