1// Copyright 2013 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5package vfs 6 7import ( 8 "fmt" 9 "go/build" 10 "io/ioutil" 11 "os" 12 pathpkg "path" 13 "path/filepath" 14 "runtime" 15) 16 17// We expose a new variable because otherwise we need to copy the findGOROOT logic again 18// from cmd/godoc which is already copied twice from the standard library. 19 20// GOROOT is the GOROOT path under which the godoc binary is running. 21// It is needed to check whether a filesystem root is under GOROOT or not. 22// This is set from cmd/godoc/main.go. 23var GOROOT = runtime.GOROOT() 24 25// OS returns an implementation of FileSystem reading from the 26// tree rooted at root. Recording a root is convenient everywhere 27// but necessary on Windows, because the slash-separated path 28// passed to Open has no way to specify a drive letter. Using a root 29// lets code refer to OS(`c:\`), OS(`d:\`) and so on. 30func OS(root string) FileSystem { 31 var t RootType 32 switch { 33 case root == GOROOT: 34 t = RootTypeGoRoot 35 case isGoPath(root): 36 t = RootTypeGoPath 37 } 38 return osFS{rootPath: root, rootType: t} 39} 40 41type osFS struct { 42 rootPath string 43 rootType RootType 44} 45 46func isGoPath(path string) bool { 47 for _, bp := range filepath.SplitList(build.Default.GOPATH) { 48 for _, gp := range filepath.SplitList(path) { 49 if bp == gp { 50 return true 51 } 52 } 53 } 54 return false 55} 56 57func (root osFS) String() string { return "os(" + root.rootPath + ")" } 58 59// RootType returns the root type for the filesystem. 60// 61// Note that we ignore the path argument because roottype is a property of 62// this filesystem. But for other filesystems, the roottype might need to be 63// dynamically deduced at call time. 64func (root osFS) RootType(path string) RootType { 65 return root.rootType 66} 67 68func (root osFS) resolve(path string) string { 69 // Clean the path so that it cannot possibly begin with ../. 70 // If it did, the result of filepath.Join would be outside the 71 // tree rooted at root. We probably won't ever see a path 72 // with .. in it, but be safe anyway. 73 path = pathpkg.Clean("/" + path) 74 75 return filepath.Join(root.rootPath, path) 76} 77 78func (root osFS) Open(path string) (ReadSeekCloser, error) { 79 f, err := os.Open(root.resolve(path)) 80 if err != nil { 81 return nil, err 82 } 83 fi, err := f.Stat() 84 if err != nil { 85 f.Close() 86 return nil, err 87 } 88 if fi.IsDir() { 89 f.Close() 90 return nil, fmt.Errorf("Open: %s is a directory", path) 91 } 92 return f, nil 93} 94 95func (root osFS) Lstat(path string) (os.FileInfo, error) { 96 return os.Lstat(root.resolve(path)) 97} 98 99func (root osFS) Stat(path string) (os.FileInfo, error) { 100 return os.Stat(root.resolve(path)) 101} 102 103func (root osFS) ReadDir(path string) ([]os.FileInfo, error) { 104 return ioutil.ReadDir(root.resolve(path)) // is sorted 105} 106