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// Copyright 2009 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
import (
"syscall"
"unsafe"
)
// Stat returns the FileInfo structure describing file.
// If there is an error, it will be of type *PathError.
func (file *File) Stat() (fi FileInfo, err error) {
if file == nil {
return nil, ErrInvalid
}
if file == nil || file.fd < 0 {
return nil, syscall.EINVAL
}
if file.isdir() {
// I don't know any better way to do that for directory
return Stat(file.name)
}
if file.name == DevNull {
return &devNullStat, nil
}
var d syscall.ByHandleFileInformation
e := syscall.GetFileInformationByHandle(syscall.Handle(file.fd), &d)
if e != nil {
return nil, &PathError{"GetFileInformationByHandle", file.name, e}
}
return &fileStat{
name: basename(file.name),
sys: syscall.Win32FileAttributeData{
FileAttributes: d.FileAttributes,
CreationTime: d.CreationTime,
LastAccessTime: d.LastAccessTime,
LastWriteTime: d.LastWriteTime,
FileSizeHigh: d.FileSizeHigh,
FileSizeLow: d.FileSizeLow,
},
vol: d.VolumeSerialNumber,
idxhi: d.FileIndexHigh,
idxlo: d.FileIndexLow,
}, nil
}
// Stat returns a FileInfo structure describing the named file.
// If there is an error, it will be of type *PathError.
func Stat(name string) (fi FileInfo, err error) {
for {
fi, err = Lstat(name)
if err != nil {
return
}
if fi.Mode()&ModeSymlink == 0 {
return
}
name, err = Readlink(name)
if err != nil {
return
}
}
return fi, err
}
// Lstat returns the FileInfo structure describing the named file.
// If the file is a symbolic link, the returned FileInfo
// describes the symbolic link. Lstat makes no attempt to follow the link.
// If there is an error, it will be of type *PathError.
func Lstat(name string) (fi FileInfo, err error) {
if len(name) == 0 {
return nil, &PathError{"Lstat", name, syscall.Errno(syscall.ERROR_PATH_NOT_FOUND)}
}
if name == DevNull {
return &devNullStat, nil
}
fs := &fileStat{name: basename(name)}
namep, e := syscall.UTF16PtrFromString(name)
if e != nil {
return nil, &PathError{"Lstat", name, e}
}
e = syscall.GetFileAttributesEx(namep, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fs.sys)))
if e != nil {
return nil, &PathError{"GetFileAttributesEx", name, e}
}
fs.path = name
if !isAbs(fs.path) {
fs.path, e = syscall.FullPath(fs.path)
if e != nil {
return nil, e
}
}
return fs, nil
}
// 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 ""
}