mirror of
https://github.com/autc04/Retro68.git
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119 lines
2.7 KiB
Go
119 lines
2.7 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package filepath
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import (
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"errors"
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"os"
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"runtime"
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)
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// isRoot returns true if path is root of file system
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// (`/` on unix and `/`, `\`, `c:\` or `c:/` on windows).
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func isRoot(path string) bool {
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if runtime.GOOS != "windows" {
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return path == "/"
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}
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switch len(path) {
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case 1:
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return os.IsPathSeparator(path[0])
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case 3:
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return path[1] == ':' && os.IsPathSeparator(path[2])
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}
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return false
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}
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// isDriveLetter returns true if path is Windows drive letter (like "c:").
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func isDriveLetter(path string) bool {
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if runtime.GOOS != "windows" {
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return false
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}
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return len(path) == 2 && path[1] == ':'
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}
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func walkLink(path string, linksWalked *int) (newpath string, islink bool, err error) {
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if *linksWalked > 255 {
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return "", false, errors.New("EvalSymlinks: too many links")
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}
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fi, err := os.Lstat(path)
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if err != nil {
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return "", false, err
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}
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if fi.Mode()&os.ModeSymlink == 0 {
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return path, false, nil
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}
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newpath, err = os.Readlink(path)
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if err != nil {
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return "", false, err
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}
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*linksWalked++
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return newpath, true, nil
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}
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func walkLinks(path string, linksWalked *int) (string, error) {
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switch dir, file := Split(path); {
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case dir == "":
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newpath, _, err := walkLink(file, linksWalked)
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return newpath, err
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case file == "":
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if isDriveLetter(dir) {
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return dir, nil
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}
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if os.IsPathSeparator(dir[len(dir)-1]) {
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if isRoot(dir) {
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return dir, nil
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}
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return walkLinks(dir[:len(dir)-1], linksWalked)
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}
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newpath, _, err := walkLink(dir, linksWalked)
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return newpath, err
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default:
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newdir, err := walkLinks(dir, linksWalked)
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if err != nil {
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return "", err
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}
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newpath, islink, err := walkLink(Join(newdir, file), linksWalked)
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if err != nil {
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return "", err
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}
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if !islink {
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return newpath, nil
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}
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if IsAbs(newpath) || os.IsPathSeparator(newpath[0]) {
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return newpath, nil
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}
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return Join(newdir, newpath), nil
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}
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}
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func walkSymlinks(path string) (string, error) {
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if path == "" {
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return path, nil
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}
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var linksWalked int // to protect against cycles
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for {
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i := linksWalked
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newpath, err := walkLinks(path, &linksWalked)
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if err != nil {
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return "", err
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}
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if runtime.GOOS == "windows" {
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// walkLinks(".", ...) always returns "." on unix.
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// But on windows it returns symlink target, if current
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// directory is a symlink. Stop the walk, if symlink
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// target is not absolute path, and return "."
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// to the caller (just like unix does).
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// Same for "C:.".
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if path[volumeNameLen(path):] == "." && !IsAbs(newpath) {
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return path, nil
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}
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}
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if i == linksWalked {
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return Clean(newpath), nil
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}
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path = newpath
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}
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}
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