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go/src/os/stat_windows.go
Russ Cox 2291cae2af os: use keyed literals for PathError
Necessary to move PathError to io/fs.

For #41190.

Change-Id: I05e87675f38a22f0570d4366b751b6169f7a1b13
Reviewed-on: https://go-review.googlesource.com/c/go/+/243900
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2020-10-20 00:59:22 +00:00

117 lines
3.6 KiB
Go

// 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"
"syscall"
"unsafe"
)
// Stat returns the FileInfo structure describing file.
// If there is an error, it will be of type *PathError.
func (file *File) Stat() (FileInfo, error) {
if file == nil {
return nil, ErrInvalid
}
if file.isdir() {
// I don't know any better way to do that for directory
return Stat(file.dirinfo.path)
}
if isWindowsNulName(file.name) {
return &devNullStat, nil
}
ft, err := file.pfd.GetFileType()
if err != nil {
return nil, &PathError{Op: "GetFileType", Path: file.name, Err: err}
}
switch ft {
case syscall.FILE_TYPE_PIPE, syscall.FILE_TYPE_CHAR:
return &fileStat{name: basename(file.name), filetype: ft}, nil
}
fs, err := newFileStatFromGetFileInformationByHandle(file.name, file.pfd.Sysfd)
if err != nil {
return nil, err
}
fs.filetype = ft
return fs, err
}
// stat implements both Stat and Lstat of a file.
func stat(funcname, name string, createFileAttrs uint32) (FileInfo, error) {
if len(name) == 0 {
return nil, &PathError{Op: funcname, Path: name, Err: syscall.Errno(syscall.ERROR_PATH_NOT_FOUND)}
}
if isWindowsNulName(name) {
return &devNullStat, nil
}
namep, err := syscall.UTF16PtrFromString(fixLongPath(name))
if err != nil {
return nil, &PathError{Op: funcname, Path: name, Err: err}
}
// Try GetFileAttributesEx first, because it is faster than CreateFile.
// See https://golang.org/issues/19922#issuecomment-300031421 for details.
var fa syscall.Win32FileAttributeData
err = syscall.GetFileAttributesEx(namep, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
if err == nil && fa.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
// Not a symlink.
fs := &fileStat{
FileAttributes: fa.FileAttributes,
CreationTime: fa.CreationTime,
LastAccessTime: fa.LastAccessTime,
LastWriteTime: fa.LastWriteTime,
FileSizeHigh: fa.FileSizeHigh,
FileSizeLow: fa.FileSizeLow,
}
if err := fs.saveInfoFromPath(name); err != nil {
return nil, err
}
return fs, nil
}
// GetFileAttributesEx fails with ERROR_SHARING_VIOLATION error for
// files, like c:\pagefile.sys. Use FindFirstFile for such files.
if err == windows.ERROR_SHARING_VIOLATION {
var fd syscall.Win32finddata
sh, err := syscall.FindFirstFile(namep, &fd)
if err != nil {
return nil, &PathError{Op: "FindFirstFile", Path: name, Err: err}
}
syscall.FindClose(sh)
fs := newFileStatFromWin32finddata(&fd)
if err := fs.saveInfoFromPath(name); err != nil {
return nil, err
}
return fs, nil
}
// Finally use CreateFile.
h, err := syscall.CreateFile(namep, 0, 0, nil,
syscall.OPEN_EXISTING, createFileAttrs, 0)
if err != nil {
return nil, &PathError{Op: "CreateFile", Path: name, Err: err}
}
defer syscall.CloseHandle(h)
return newFileStatFromGetFileInformationByHandle(name, h)
}
// statNolog implements Stat for Windows.
func statNolog(name string) (FileInfo, error) {
return stat("Stat", name, syscall.FILE_FLAG_BACKUP_SEMANTICS)
}
// lstatNolog implements Lstat for Windows.
func lstatNolog(name string) (FileInfo, error) {
attrs := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS)
// Use FILE_FLAG_OPEN_REPARSE_POINT, otherwise CreateFile will follow symlink.
// See https://docs.microsoft.com/en-us/windows/desktop/FileIO/symbolic-link-effects-on-file-systems-functions#createfile-and-createfiletransacted
attrs |= syscall.FILE_FLAG_OPEN_REPARSE_POINT
return stat("Lstat", name, attrs)
}