blob: 35d050946e66e8a79b5da4cdb944ebf7fb3fa609 [file] [log] [blame]
// Copyright 2013 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 vfs
import (
pathpkg "path"
// We expose a new variable because otherwise we need to copy the findGOROOT logic again
// from cmd/godoc which is already copied twice from the standard library.
// GOROOT is the GOROOT path under which the godoc binary is running.
// It is needed to check whether a filesystem root is under GOROOT or not.
// This is set from cmd/godoc/main.go.
var GOROOT = runtime.GOROOT()
// OS returns an implementation of FileSystem reading from the
// tree rooted at root. Recording a root is convenient everywhere
// but necessary on Windows, because the slash-separated path
// passed to Open has no way to specify a drive letter. Using a root
// lets code refer to OS(`c:\`), OS(`d:\`) and so on.
func OS(root string) FileSystem {
var t RootType
switch {
case root == GOROOT:
t = RootTypeGoRoot
case isGoPath(root):
t = RootTypeGoPath
return osFS{rootPath: root, rootType: t}
type osFS struct {
rootPath string
rootType RootType
func isGoPath(path string) bool {
for _, bp := range filepath.SplitList(build.Default.GOPATH) {
for _, gp := range filepath.SplitList(path) {
if bp == gp {
return true
return false
func (root osFS) String() string { return "os(" + root.rootPath + ")" }
// RootType returns the root type for the filesystem.
// Note that we ignore the path argument because roottype is a property of
// this filesystem. But for other filesystems, the roottype might need to be
// dynamically deduced at call time.
func (root osFS) RootType(path string) RootType {
return root.rootType
func (root osFS) resolve(path string) string {
// Clean the path so that it cannot possibly begin with ../.
// If it did, the result of filepath.Join would be outside the
// tree rooted at root. We probably won't ever see a path
// with .. in it, but be safe anyway.
path = pathpkg.Clean("/" + path)
return filepath.Join(root.rootPath, path)
func (root osFS) Open(path string) (ReadSeekCloser, error) {
f, err := os.Open(root.resolve(path))
if err != nil {
return nil, err
fi, err := f.Stat()
if err != nil {
return nil, err
if fi.IsDir() {
return nil, fmt.Errorf("Open: %s is a directory", path)
return f, nil
func (root osFS) Lstat(path string) (os.FileInfo, error) {
return os.Lstat(root.resolve(path))
func (root osFS) Stat(path string) (os.FileInfo, error) {
return os.Stat(root.resolve(path))
func (root osFS) ReadDir(path string) ([]os.FileInfo, error) {
return ioutil.ReadDir(root.resolve(path)) // is sorted