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mirror of https://github.com/octoleo/restic.git synced 2024-11-30 08:44:02 +00:00
restic/internal/fs/file_windows.go
Michael Eischer ff7ef5007e Replace most usages of ioutil with the underlying function
The ioutil functions are deprecated since Go 1.17 and only wrap another
library function. Thus directly call the underlying function.

This commit only mechanically replaces the function calls.
2022-12-02 19:36:43 +01:00

80 lines
2.2 KiB
Go

package fs
import (
"math/rand"
"os"
"path/filepath"
"strconv"
"strings"
"time"
"golang.org/x/sys/windows"
)
// fixpath returns an absolute path on windows, so restic can open long file
// names.
func fixpath(name string) string {
abspath, err := filepath.Abs(name)
if err == nil {
// Check if \\?\UNC\ already exist
if strings.HasPrefix(abspath, `\\?\UNC\`) {
return abspath
}
// Check if \\?\ already exist
if strings.HasPrefix(abspath, `\\?\`) {
return abspath
}
// Check if path starts with \\
if strings.HasPrefix(abspath, `\\`) {
return strings.Replace(abspath, `\\`, `\\?\UNC\`, 1)
}
// Normal path
return `\\?\` + abspath
}
return name
}
// TempFile creates a temporary file which is marked as delete-on-close
func TempFile(dir, prefix string) (f *os.File, err error) {
// slightly modified implementation of os.CreateTemp(dir, prefix) to allow us to add
// the FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE flags.
// These provide two large benefits:
// FILE_ATTRIBUTE_TEMPORARY tells Windows to keep the file in memory only if possible
// which reduces the amount of unnecessary disk writes.
// FILE_FLAG_DELETE_ON_CLOSE instructs Windows to automatically delete the file once
// all file descriptors are closed.
if dir == "" {
dir = os.TempDir()
}
access := uint32(windows.GENERIC_READ | windows.GENERIC_WRITE)
creation := uint32(windows.CREATE_NEW)
share := uint32(0) // prevent other processes from accessing the file
flags := uint32(windows.FILE_ATTRIBUTE_TEMPORARY | windows.FILE_FLAG_DELETE_ON_CLOSE)
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
for i := 0; i < 10000; i++ {
randSuffix := strconv.Itoa(int(1e9 + rnd.Intn(1e9)%1e9))[1:]
path := filepath.Join(dir, prefix+randSuffix)
ptr, err := windows.UTF16PtrFromString(path)
if err != nil {
return nil, err
}
h, err := windows.CreateFile(ptr, access, share, nil, creation, flags, 0)
if os.IsExist(err) {
continue
}
return os.NewFile(uintptr(h), path), err
}
// Proper error handling is still to do
return nil, os.ErrExist
}
// Chmod changes the mode of the named file to mode.
func Chmod(name string, mode os.FileMode) error {
return os.Chmod(fixpath(name), mode)
}