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// Copyright 2012 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 filepath
import (
"strings"
"syscall"
)
// normVolumeName is like VolumeName, but makes drive letter upper case.
// result of EvalSymlinks must be unique, so we have
// EvalSymlinks(`c:\a`) == EvalSymlinks(`C:\a`).
func normVolumeName(path string) string {
volume := VolumeName(path)
if len(volume) > 2 { // isUNC
return volume
}
return strings.ToUpper(volume)
}
// normBase returns the last element of path with correct case.
func normBase(path string) (string, error) {
p, err := syscall.UTF16PtrFromString(path)
if err != nil {
return "", err
}
var data syscall.Win32finddata
h, err := syscall.FindFirstFile(p, &data)
if err != nil {
return "", err
}
syscall.FindClose(h)
return syscall.UTF16ToString(data.FileName[:]), nil
}
// baseIsDotDot reports whether the last element of path is "..".
// The given path should be 'Clean'-ed in advance.
func baseIsDotDot(path string) bool {
i := strings.LastIndexByte(path, Separator)
return path[i+1:] == ".."
}
// toNorm returns the normalized path that is guaranteed to be unique.
// It should accept the following formats:
// - UNC paths (e.g \\server\share\foo\bar)
// - absolute paths (e.g C:\foo\bar)
// - relative paths begin with drive letter (e.g C:foo\bar, C:..\foo\bar, C:.., C:.)
// - relative paths begin with '\' (e.g \foo\bar)
// - relative paths begin without '\' (e.g foo\bar, ..\foo\bar, .., .)
//
// The returned normalized path will be in the same form (of 5 listed above) as the input path.
// If two paths A and B are indicating the same file with the same format, toNorm(A) should be equal to toNorm(B).
// The normBase parameter should be equal to the normBase func, except for in tests. See docs on the normBase func.
func toNorm(path string, normBase func(string) (string, error)) (string, error) {
if path == "" {
return path, nil
}
volume := normVolumeName(path)
path = path[len(volume):]
// skip special cases
if path == "" || path == "." || path == `\` {
return volume + path, nil
}
var normPath string
for {
if baseIsDotDot(path) {
normPath = path + `\` + normPath
break
}
name, err := normBase(volume + path)
if err != nil {
return "", err
}
normPath = name + `\` + normPath
i := strings.LastIndexByte(path, Separator)
if i == -1 {
break
}
if i == 0 { // `\Go` or `C:\Go`
normPath = `\` + normPath
break
}
path = path[:i]
}
normPath = normPath[:len(normPath)-1] // remove trailing '\'
return volume + normPath, nil
}
func evalSymlinks(path string) (string, error) {
newpath, err := walkSymlinks(path)
if err != nil {
return "", err
}
newpath, err = toNorm(newpath, normBase)
if err != nil {
return "", err
}
return newpath, nil
}