src/os/types_windows.go - go - Git at Google

 // 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 (
 	"internal/syscall/windows"
 	"sync"
 	"syscall"
 	"time"
 	"unsafe"
 )

 // A fileStat is the implementation of FileInfo returned by Stat and Lstat.
 type fileStat struct {
 	name string

 	// from ByHandleFileInformation, Win32FileAttributeData and Win32finddata
 	FileAttributes uint32
 	CreationTime   syscall.Filetime
 	LastAccessTime syscall.Filetime
 	LastWriteTime  syscall.Filetime
 	FileSizeHigh   uint32
 	FileSizeLow    uint32

 	// from Win32finddata
 	Reserved0 uint32

 	// what syscall.GetFileType returns
 	filetype uint32

 	// used to implement SameFile
 	sync.Mutex
 	path             string
 	vol              uint32
 	idxhi            uint32
 	idxlo            uint32
 	appendNameToPath bool
 }

 // newFileStatFromGetFileInformationByHandle calls GetFileInformationByHandle
 // to gather all required information about the file handle h.
 func newFileStatFromGetFileInformationByHandle(path string, h syscall.Handle) (fs *fileStat, err error) {
 	var d syscall.ByHandleFileInformation
 	err = syscall.GetFileInformationByHandle(h, &d)
 	if err != nil {
 		return nil, &PathError{"GetFileInformationByHandle", path, err}
 	}
 	return &fileStat{
 		name:           basename(path),
 		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,
 		// fileStat.path is used by os.SameFile to decide if it needs
 		// to fetch vol, idxhi and idxlo. But these are already set,
 		// so set fileStat.path to "" to prevent os.SameFile doing it again.
 	}, nil
 }

 // newFileStatFromWin32finddata copies all required information
 // from syscall.Win32finddata d into the newly created fileStat.
 func newFileStatFromWin32finddata(d *syscall.Win32finddata) *fileStat {
 	return &fileStat{
 		FileAttributes: d.FileAttributes,
 		CreationTime:   d.CreationTime,
 		LastAccessTime: d.LastAccessTime,
 		LastWriteTime:  d.LastWriteTime,
 		FileSizeHigh:   d.FileSizeHigh,
 		FileSizeLow:    d.FileSizeLow,
 		Reserved0:      d.Reserved0,
 	}
 }

 // newFileStatFromGetFileAttributesExOrFindFirstFile calls GetFileAttributesEx
 // and FindFirstFile to gather all required information about the provided file path pathp.
 func newFileStatFromGetFileAttributesExOrFindFirstFile(path string, pathp *uint16) (*fileStat, error) {
 	// As suggested by Microsoft, use GetFileAttributes() to acquire the file information,
 	// and if it's a reparse point use FindFirstFile() to get the tag:
 	// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363940(v=vs.85).aspx
 	// Notice that always calling FindFirstFile can create performance problems
 	// (https://golang.org/issues/19922#issuecomment-300031421)
 	var fa syscall.Win32FileAttributeData
 	err := syscall.GetFileAttributesEx(pathp, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
 	if err == nil && fa.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
 		// Not a symlink.
 		return &fileStat{
 			FileAttributes: fa.FileAttributes,
 			CreationTime:   fa.CreationTime,
 			LastAccessTime: fa.LastAccessTime,
 			LastWriteTime:  fa.LastWriteTime,
 			FileSizeHigh:   fa.FileSizeHigh,
 			FileSizeLow:    fa.FileSizeLow,
 		}, nil
 	}
 	// GetFileAttributesEx returns ERROR_INVALID_NAME if called
 	// for invalid file name like "*.txt". Do not attempt to call
 	// FindFirstFile with "*.txt", because FindFirstFile will
 	// succeed. So just return ERROR_INVALID_NAME instead.
 	// see https://golang.org/issue/24999 for details.
 	if errno, _ := err.(syscall.Errno); errno == windows.ERROR_INVALID_NAME {
 		return nil, &PathError{"GetFileAttributesEx", path, err}
 	}
 	// We might have symlink here. But some directories also have
 	// FileAttributes FILE_ATTRIBUTE_REPARSE_POINT bit set.
 	// For example, OneDrive directory is like that
 	// (see golang.org/issue/22579 for details).
 	// So use FindFirstFile instead to distinguish directories like
 	// OneDrive from real symlinks (see instructions described at
 	// https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
 	// and in particular bits about using both FileAttributes and
 	// Reserved0 fields).
 	var fd syscall.Win32finddata
 	sh, err := syscall.FindFirstFile(pathp, &fd)
 	if err != nil {
 		return nil, &PathError{"FindFirstFile", path, err}
 	}
 	syscall.FindClose(sh)

 	return newFileStatFromWin32finddata(&fd), nil
 }

 func (fs *fileStat) updatePathAndName(name string) error {
 	fs.path = name
 	if !isAbs(fs.path) {
 		var err error
 		fs.path, err = syscall.FullPath(fs.path)
 		if err != nil {
 			return &PathError{"FullPath", name, err}
 		}
 	}
 	fs.name = basename(name)
 	return nil
 }

 func (fs *fileStat) isSymlink() bool {
 	// Use instructions described at
 	// https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
 	// to recognize whether it's a symlink.
 	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
 		return false
 	}
 	return fs.Reserved0 == syscall.IO_REPARSE_TAG_SYMLINK ||
 		fs.Reserved0 == windows.IO_REPARSE_TAG_MOUNT_POINT
 }

 func (fs *fileStat) Size() int64 {
 	return int64(fs.FileSizeHigh)<<32 + int64(fs.FileSizeLow)
 }

 func (fs *fileStat) Mode() (m FileMode) {
 	if fs == &devNullStat {
 		return ModeDevice | ModeCharDevice | 0666
 	}
 	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_READONLY != 0 {
 		m |= 0444
 	} else {
 		m |= 0666
 	}
 	if fs.isSymlink() {
 		return m | ModeSymlink
 	}
 	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
 		m |= ModeDir | 0111
 	}
 	switch fs.filetype {
 	case syscall.FILE_TYPE_PIPE:
 		m |= ModeNamedPipe
 	case syscall.FILE_TYPE_CHAR:
 		m |= ModeDevice | ModeCharDevice
 	}
 	return m
 }

 func (fs *fileStat) ModTime() time.Time {
 	return time.Unix(0, fs.LastWriteTime.Nanoseconds())
 }

 // Sys returns syscall.Win32FileAttributeData for file fs.
 func (fs *fileStat) Sys() interface{} {
 	return &syscall.Win32FileAttributeData{
 		FileAttributes: fs.FileAttributes,
 		CreationTime:   fs.CreationTime,
 		LastAccessTime: fs.LastAccessTime,
 		LastWriteTime:  fs.LastWriteTime,
 		FileSizeHigh:   fs.FileSizeHigh,
 		FileSizeLow:    fs.FileSizeLow,
 	}
 }

 func (fs *fileStat) loadFileId() error {
 	fs.Lock()
 	defer fs.Unlock()
 	if fs.path == "" {
 		// already done
 		return nil
 	}
 	var path string
 	if fs.appendNameToPath {
 		path = fs.path + `\` + fs.name
 	} else {
 		path = fs.path
 	}
 	pathp, err := syscall.UTF16PtrFromString(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(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())
 }
	// 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 (
	"internal/syscall/windows"
	"sync"
	"syscall"
	"time"
	"unsafe"
	)

	// A fileStat is the implementation of FileInfo returned by Stat and Lstat.
	type fileStat struct {
	name string

	// from ByHandleFileInformation, Win32FileAttributeData and Win32finddata
	FileAttributes uint32
	CreationTime syscall.Filetime
	LastAccessTime syscall.Filetime
	LastWriteTime syscall.Filetime
	FileSizeHigh uint32
	FileSizeLow uint32

	// from Win32finddata
	Reserved0 uint32

	// what syscall.GetFileType returns
	filetype uint32

	// used to implement SameFile
	sync.Mutex
	path string
	vol uint32
	idxhi uint32
	idxlo uint32
	appendNameToPath bool
	}

	// newFileStatFromGetFileInformationByHandle calls GetFileInformationByHandle
	// to gather all required information about the file handle h.
	func newFileStatFromGetFileInformationByHandle(path string, h syscall.Handle) (fs *fileStat, err error) {
	var d syscall.ByHandleFileInformation
	err = syscall.GetFileInformationByHandle(h, &d)
	if err != nil {
	return nil, &PathError{"GetFileInformationByHandle", path, err}
	}
	return &fileStat{
	name: basename(path),
	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,
	// fileStat.path is used by os.SameFile to decide if it needs
	// to fetch vol, idxhi and idxlo. But these are already set,
	// so set fileStat.path to "" to prevent os.SameFile doing it again.
	}, nil
	}

	// newFileStatFromWin32finddata copies all required information
	// from syscall.Win32finddata d into the newly created fileStat.
	func newFileStatFromWin32finddata(d syscall.Win32finddata) fileStat {
	return &fileStat{
	FileAttributes: d.FileAttributes,
	CreationTime: d.CreationTime,
	LastAccessTime: d.LastAccessTime,
	LastWriteTime: d.LastWriteTime,
	FileSizeHigh: d.FileSizeHigh,
	FileSizeLow: d.FileSizeLow,
	Reserved0: d.Reserved0,
	}
	}

	// newFileStatFromGetFileAttributesExOrFindFirstFile calls GetFileAttributesEx
	// and FindFirstFile to gather all required information about the provided file path pathp.
	func newFileStatFromGetFileAttributesExOrFindFirstFile(path string, pathp uint16) (fileStat, error) {
	// As suggested by Microsoft, use GetFileAttributes() to acquire the file information,
	// and if it's a reparse point use FindFirstFile() to get the tag:
	// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363940(v=vs.85).aspx
	// Notice that always calling FindFirstFile can create performance problems
	// (https://golang.org/issues/19922#issuecomment-300031421)
	var fa syscall.Win32FileAttributeData
	err := syscall.GetFileAttributesEx(pathp, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
	if err == nil && fa.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
	// Not a symlink.
	return &fileStat{
	FileAttributes: fa.FileAttributes,
	CreationTime: fa.CreationTime,
	LastAccessTime: fa.LastAccessTime,
	LastWriteTime: fa.LastWriteTime,
	FileSizeHigh: fa.FileSizeHigh,
	FileSizeLow: fa.FileSizeLow,
	}, nil
	}
	// GetFileAttributesEx returns ERROR_INVALID_NAME if called
	// for invalid file name like "*.txt". Do not attempt to call
	// FindFirstFile with "*.txt", because FindFirstFile will
	// succeed. So just return ERROR_INVALID_NAME instead.
	// see https://golang.org/issue/24999 for details.
	if errno, _ := err.(syscall.Errno); errno == windows.ERROR_INVALID_NAME {
	return nil, &PathError{"GetFileAttributesEx", path, err}
	}
	// We might have symlink here. But some directories also have
	// FileAttributes FILE_ATTRIBUTE_REPARSE_POINT bit set.
	// For example, OneDrive directory is like that
	// (see golang.org/issue/22579 for details).
	// So use FindFirstFile instead to distinguish directories like
	// OneDrive from real symlinks (see instructions described at
	// https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
	// and in particular bits about using both FileAttributes and
	// Reserved0 fields).
	var fd syscall.Win32finddata
	sh, err := syscall.FindFirstFile(pathp, &fd)
	if err != nil {
	return nil, &PathError{"FindFirstFile", path, err}
	}
	syscall.FindClose(sh)

	return newFileStatFromWin32finddata(&fd), nil
	}

	func (fs *fileStat) updatePathAndName(name string) error {
	fs.path = name
	if !isAbs(fs.path) {
	var err error
	fs.path, err = syscall.FullPath(fs.path)
	if err != nil {
	return &PathError{"FullPath", name, err}
	}
	}
	fs.name = basename(name)
	return nil
	}

	func (fs *fileStat) isSymlink() bool {
	// Use instructions described at
	// https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
	// to recognize whether it's a symlink.
	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
	return false
	}
	return fs.Reserved0 == syscall.IO_REPARSE_TAG_SYMLINK \|\|
	fs.Reserved0 == windows.IO_REPARSE_TAG_MOUNT_POINT
	}

	func (fs *fileStat) Size() int64 {
	return int64(fs.FileSizeHigh)<<32 + int64(fs.FileSizeLow)
	}

	func (fs *fileStat) Mode() (m FileMode) {
	if fs == &devNullStat {
	return ModeDevice \| ModeCharDevice \| 0666
	}
	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_READONLY != 0 {
	m \|= 0444
	} else {
	m \|= 0666
	}
	if fs.isSymlink() {
	return m \| ModeSymlink
	}
	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
	m \|= ModeDir \| 0111
	}
	switch fs.filetype {
	case syscall.FILE_TYPE_PIPE:
	m \|= ModeNamedPipe
	case syscall.FILE_TYPE_CHAR:
	m \|= ModeDevice \| ModeCharDevice
	}
	return m
	}

	func (fs *fileStat) ModTime() time.Time {
	return time.Unix(0, fs.LastWriteTime.Nanoseconds())
	}

	// Sys returns syscall.Win32FileAttributeData for file fs.
	func (fs *fileStat) Sys() interface{} {
	return &syscall.Win32FileAttributeData{
	FileAttributes: fs.FileAttributes,
	CreationTime: fs.CreationTime,
	LastAccessTime: fs.LastAccessTime,
	LastWriteTime: fs.LastWriteTime,
	FileSizeHigh: fs.FileSizeHigh,
	FileSizeLow: fs.FileSizeLow,
	}
	}

	func (fs *fileStat) loadFileId() error {
	fs.Lock()
	defer fs.Unlock()
	if fs.path == "" {
	// already done
	return nil
	}
	var path string
	if fs.appendNameToPath {
	path = fs.path + `\` + fs.name
	} else {
	path = fs.path
	}
	pathp, err := syscall.UTF16PtrFromString(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(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())
	}