1// Copyright 2012 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 filepath 6 7import ( 8 "strings" 9 "syscall" 10) 11 12// normVolumeName is like VolumeName, but makes drive letter upper case. 13// result of EvalSymlinks must be unique, so we have 14// EvalSymlinks(`c:\a`) == EvalSymlinks(`C:\a`). 15func normVolumeName(path string) string { 16 volume := VolumeName(path) 17 18 if len(volume) > 2 { // isUNC 19 return volume 20 } 21 22 return strings.ToUpper(volume) 23} 24 25// normBase returns the last element of path with correct case. 26func normBase(path string) (string, error) { 27 p, err := syscall.UTF16PtrFromString(path) 28 if err != nil { 29 return "", err 30 } 31 32 var data syscall.Win32finddata 33 34 h, err := syscall.FindFirstFile(p, &data) 35 if err != nil { 36 return "", err 37 } 38 syscall.FindClose(h) 39 40 return syscall.UTF16ToString(data.FileName[:]), nil 41} 42 43// baseIsDotDot reports whether the last element of path is "..". 44// The given path should be 'Clean'-ed in advance. 45func baseIsDotDot(path string) bool { 46 i := strings.LastIndexByte(path, Separator) 47 return path[i+1:] == ".." 48} 49 50// toNorm returns the normalized path that is guaranteed to be unique. 51// It should accept the following formats: 52// * UNC paths (e.g \\server\share\foo\bar) 53// * absolute paths (e.g C:\foo\bar) 54// * relative paths begin with drive letter (e.g C:foo\bar, C:..\foo\bar, C:.., C:.) 55// * relative paths begin with '\' (e.g \foo\bar) 56// * relative paths begin without '\' (e.g foo\bar, ..\foo\bar, .., .) 57// The returned normalized path will be in the same form (of 5 listed above) as the input path. 58// If two paths A and B are indicating the same file with the same format, toNorm(A) should be equal to toNorm(B). 59// The normBase parameter should be equal to the normBase func, except for in tests. See docs on the normBase func. 60func toNorm(path string, normBase func(string) (string, error)) (string, error) { 61 if path == "" { 62 return path, nil 63 } 64 65 path = Clean(path) 66 67 volume := normVolumeName(path) 68 path = path[len(volume):] 69 70 // skip special cases 71 if path == "" || path == "." || path == `\` { 72 return volume + path, nil 73 } 74 75 var normPath string 76 77 for { 78 if baseIsDotDot(path) { 79 normPath = path + `\` + normPath 80 81 break 82 } 83 84 name, err := normBase(volume + path) 85 if err != nil { 86 return "", err 87 } 88 89 normPath = name + `\` + normPath 90 91 i := strings.LastIndexByte(path, Separator) 92 if i == -1 { 93 break 94 } 95 if i == 0 { // `\Go` or `C:\Go` 96 normPath = `\` + normPath 97 98 break 99 } 100 101 path = path[:i] 102 } 103 104 normPath = normPath[:len(normPath)-1] // remove trailing '\' 105 106 return volume + normPath, nil 107} 108 109func evalSymlinks(path string) (string, error) { 110 newpath, err := walkSymlinks(path) 111 if err != nil { 112 return "", err 113 } 114 newpath, err = toNorm(newpath, normBase) 115 if err != nil { 116 return "", err 117 } 118 return newpath, nil 119} 120