syncthing/lib/fs/basicfs_realcaser_windows.go
Simon Frei 932d8c69de lib/fs: Properly handle case insensitive systems (fixes #1787, fixes #2739, fixes #5708)
With this change we emulate a case sensitive filesystem on top of
insensitive filesystems. This means we correctly pick up case-only renames
and throw a case conflict error when there would be multiple files differing
only in case.

This safety check has a small performance hit (about 20% more filesystem
operations when scanning for changes). The new advanced folder option
`caseSensitiveFS` can be used to disable the safety checks, retaining the
previous behavior on systems known to be fully case sensitive.

Co-authored-by: Jakob Borg <jakob@kastelo.net>
2020-07-28 11:15:11 +02:00

59 lines
1.3 KiB
Go

// Copyright (C) 2020 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
// +build windows
package fs
import (
"path/filepath"
"strings"
"syscall"
)
type basicRealCaserWindows struct {
uri string
}
func newBasicRealCaser(fs Filesystem) realCaser {
return &basicRealCaserWindows{fs.URI()}
}
// RealCase returns the correct case for the given name, which is a relative
// path below root, as it exists on disk.
func (r *basicRealCaserWindows) realCase(name string) (string, error) {
if name == "." {
return ".", nil
}
path := r.uri
comps := strings.Split(name, string(PathSeparator))
var err error
for i, comp := range comps {
path = filepath.Join(path, comp)
comps[i], err = r.realCaseBase(path)
if err != nil {
return "", err
}
}
return filepath.Join(comps...), nil
}
func (*basicRealCaserWindows) realCaseBase(path string) (string, error) {
p, err := syscall.UTF16PtrFromString(fixLongPath(path))
if err != nil {
return "", err
}
var fd syscall.Win32finddata
h, err := syscall.FindFirstFile(p, &fd)
if err != nil {
return "", err
}
syscall.FindClose(h)
return syscall.UTF16ToString(fd.FileName[:]), nil
}
func (r *basicRealCaserWindows) dropCache() {}