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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 (
"sync"
"syscall"
"time"
)
// A fileStat is the implementation of FileInfo returned by Stat and Lstat.
type fileStat struct {
name string
sys syscall.Win32FileAttributeData
// used to implement SameFile
sync.Mutex
path string
vol uint32
idxhi uint32
idxlo uint32
}
func (fs *fileStat) Size() int64 {
return int64(fs.sys.FileSizeHigh)<<32 + int64(fs.sys.FileSizeLow)
}
func (fs *fileStat) Mode() (m FileMode) {
if fs == &devNullStat {
return ModeDevice | ModeCharDevice | 0666
}
if fs.sys.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
m |= ModeDir | 0111
}
if fs.sys.FileAttributes&syscall.FILE_ATTRIBUTE_READONLY != 0 {
m |= 0444
} else {
m |= 0666
}
return m
}
func (fs *fileStat) ModTime() time.Time {
return time.Unix(0, fs.sys.LastWriteTime.Nanoseconds())
}
// Sys returns syscall.Win32FileAttributeData for file fs.
func (fs *fileStat) Sys() interface{} { return &fs.sys }
func (fs *fileStat) loadFileId() error {
fs.Lock()
defer fs.Unlock()
if fs.path == "" {
// already done
return nil
}
pathp, err := syscall.UTF16PtrFromString(fs.path)
if err != nil {
return err
}
h, err := syscall.CreateFile(pathp, 0, 0, nil, syscall.OPEN_EXISTING, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
if err != nil {
return err
}
defer syscall.CloseHandle(h)
var i syscall.ByHandleFileInformation
err = syscall.GetFileInformationByHandle(syscall.Handle(h), &i)
if err != nil {
return err
}
fs.path = ""
fs.vol = i.VolumeSerialNumber
fs.idxhi = i.FileIndexHigh
fs.idxlo = i.FileIndexLow
return nil
}
// devNullStat is fileStat structure describing DevNull file ("NUL").
var devNullStat = fileStat{
name: DevNull,
// hopefully this will work for SameFile
vol: 0,
idxhi: 0,
idxlo: 0,
}
func sameFile(fs1, fs2 *fileStat) bool {
e := fs1.loadFileId()
if e != nil {
return false
}
e = fs2.loadFileId()
if e != nil {
return false
}
return fs1.vol == fs2.vol && fs1.idxhi == fs2.idxhi && fs1.idxlo == fs2.idxlo
}
// For testing.
func atime(fi FileInfo) time.Time {
return time.Unix(0, fi.Sys().(*syscall.Win32FileAttributeData).LastAccessTime.Nanoseconds())
}