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-rw-r--r--src/os/path_windows.go220
1 files changed, 220 insertions, 0 deletions
diff --git a/src/os/path_windows.go b/src/os/path_windows.go
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+// Copyright 2011 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 os
+
+const (
+ PathSeparator = '\\' // OS-specific path separator
+ PathListSeparator = ';' // OS-specific path list separator
+)
+
+// IsPathSeparator reports whether c is a directory separator character.
+func IsPathSeparator(c uint8) bool {
+ // NOTE: Windows accept / as path separator.
+ return c == '\\' || c == '/'
+}
+
+// basename removes trailing slashes and the leading
+// directory name and drive letter from path name.
+func basename(name string) string {
+ // Remove drive letter
+ if len(name) == 2 && name[1] == ':' {
+ name = "."
+ } else if len(name) > 2 && name[1] == ':' {
+ name = name[2:]
+ }
+ i := len(name) - 1
+ // Remove trailing slashes
+ for ; i > 0 && (name[i] == '/' || name[i] == '\\'); i-- {
+ name = name[:i]
+ }
+ // Remove leading directory name
+ for i--; i >= 0; i-- {
+ if name[i] == '/' || name[i] == '\\' {
+ name = name[i+1:]
+ break
+ }
+ }
+ return name
+}
+
+func isAbs(path string) (b bool) {
+ v := volumeName(path)
+ if v == "" {
+ return false
+ }
+ path = path[len(v):]
+ if path == "" {
+ return false
+ }
+ return IsPathSeparator(path[0])
+}
+
+func volumeName(path string) (v string) {
+ if len(path) < 2 {
+ return ""
+ }
+ // with drive letter
+ c := path[0]
+ if path[1] == ':' &&
+ ('0' <= c && c <= '9' || 'a' <= c && c <= 'z' ||
+ 'A' <= c && c <= 'Z') {
+ return path[:2]
+ }
+ // is it UNC
+ if l := len(path); l >= 5 && IsPathSeparator(path[0]) && IsPathSeparator(path[1]) &&
+ !IsPathSeparator(path[2]) && path[2] != '.' {
+ // first, leading `\\` and next shouldn't be `\`. its server name.
+ for n := 3; n < l-1; n++ {
+ // second, next '\' shouldn't be repeated.
+ if IsPathSeparator(path[n]) {
+ n++
+ // third, following something characters. its share name.
+ if !IsPathSeparator(path[n]) {
+ if path[n] == '.' {
+ break
+ }
+ for ; n < l; n++ {
+ if IsPathSeparator(path[n]) {
+ break
+ }
+ }
+ return path[:n]
+ }
+ break
+ }
+ }
+ }
+ return ""
+}
+
+func fromSlash(path string) string {
+ // Replace each '/' with '\\' if present
+ var pathbuf []byte
+ var lastSlash int
+ for i, b := range path {
+ if b == '/' {
+ if pathbuf == nil {
+ pathbuf = make([]byte, len(path))
+ }
+ copy(pathbuf[lastSlash:], path[lastSlash:i])
+ pathbuf[i] = '\\'
+ lastSlash = i + 1
+ }
+ }
+ if pathbuf == nil {
+ return path
+ }
+
+ copy(pathbuf[lastSlash:], path[lastSlash:])
+ return string(pathbuf)
+}
+
+func dirname(path string) string {
+ vol := volumeName(path)
+ i := len(path) - 1
+ for i >= len(vol) && !IsPathSeparator(path[i]) {
+ i--
+ }
+ dir := path[len(vol) : i+1]
+ last := len(dir) - 1
+ if last > 0 && IsPathSeparator(dir[last]) {
+ dir = dir[:last]
+ }
+ if dir == "" {
+ dir = "."
+ }
+ return vol + dir
+}
+
+// fixLongPath returns the extended-length (\\?\-prefixed) form of
+// path when needed, in order to avoid the default 260 character file
+// path limit imposed by Windows. If path is not easily converted to
+// the extended-length form (for example, if path is a relative path
+// or contains .. elements), or is short enough, fixLongPath returns
+// path unmodified.
+//
+// See https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#maxpath
+func fixLongPath(path string) string {
+ // Do nothing (and don't allocate) if the path is "short".
+ // Empirically (at least on the Windows Server 2013 builder),
+ // the kernel is arbitrarily okay with < 248 bytes. That
+ // matches what the docs above say:
+ // "When using an API to create a directory, the specified
+ // path cannot be so long that you cannot append an 8.3 file
+ // name (that is, the directory name cannot exceed MAX_PATH
+ // minus 12)." Since MAX_PATH is 260, 260 - 12 = 248.
+ //
+ // The MSDN docs appear to say that a normal path that is 248 bytes long
+ // will work; empirically the path must be less then 248 bytes long.
+ if len(path) < 248 {
+ // Don't fix. (This is how Go 1.7 and earlier worked,
+ // not automatically generating the \\?\ form)
+ return path
+ }
+
+ // The extended form begins with \\?\, as in
+ // \\?\c:\windows\foo.txt or \\?\UNC\server\share\foo.txt.
+ // The extended form disables evaluation of . and .. path
+ // elements and disables the interpretation of / as equivalent
+ // to \. The conversion here rewrites / to \ and elides
+ // . elements as well as trailing or duplicate separators. For
+ // simplicity it avoids the conversion entirely for relative
+ // paths or paths containing .. elements. For now,
+ // \\server\share paths are not converted to
+ // \\?\UNC\server\share paths because the rules for doing so
+ // are less well-specified.
+ if len(path) >= 2 && path[:2] == `\\` {
+ // Don't canonicalize UNC paths.
+ return path
+ }
+ if !isAbs(path) {
+ // Relative path
+ return path
+ }
+
+ const prefix = `\\?`
+
+ pathbuf := make([]byte, len(prefix)+len(path)+len(`\`))
+ copy(pathbuf, prefix)
+ n := len(path)
+ r, w := 0, len(prefix)
+ for r < n {
+ switch {
+ case IsPathSeparator(path[r]):
+ // empty block
+ r++
+ case path[r] == '.' && (r+1 == n || IsPathSeparator(path[r+1])):
+ // /./
+ r++
+ case r+1 < n && path[r] == '.' && path[r+1] == '.' && (r+2 == n || IsPathSeparator(path[r+2])):
+ // /../ is currently unhandled
+ return path
+ default:
+ pathbuf[w] = '\\'
+ w++
+ for ; r < n && !IsPathSeparator(path[r]); r++ {
+ pathbuf[w] = path[r]
+ w++
+ }
+ }
+ }
+ // A drive's root directory needs a trailing \
+ if w == len(`\\?\c:`) {
+ pathbuf[w] = '\\'
+ w++
+ }
+ return string(pathbuf[:w])
+}
+
+// fixRootDirectory fixes a reference to a drive's root directory to
+// have the required trailing slash.
+func fixRootDirectory(p string) string {
+ if len(p) == len(`\\?\c:`) {
+ if IsPathSeparator(p[0]) && IsPathSeparator(p[1]) && p[2] == '?' && IsPathSeparator(p[3]) && p[5] == ':' {
+ return p + `\`
+ }
+ }
+ return p
+}