forked from rosa/hakurei
Ophestra
470e545d27
This is a pretty solid implementation backed by robust tests, with a much cleaner interface. Signed-off-by: Ophestra <cat@gensokyo.uk>
58 lines
1.3 KiB
Go
58 lines
1.3 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build windows
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package filelock
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import (
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"internal/syscall/windows"
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"io/fs"
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"syscall"
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)
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type lockType uint32
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const (
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readLock lockType = 0
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writeLock lockType = windows.LOCKFILE_EXCLUSIVE_LOCK
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)
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const (
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reserved = 0
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allBytes = ^uint32(0)
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)
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func lock(f File, lt lockType) error {
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// Per https://golang.org/issue/19098, “Programs currently expect the Fd
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// method to return a handle that uses ordinary synchronous I/O.”
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// However, LockFileEx still requires an OVERLAPPED structure,
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// which contains the file offset of the beginning of the lock range.
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// We want to lock the entire file, so we leave the offset as zero.
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ol := new(syscall.Overlapped)
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err := windows.LockFileEx(syscall.Handle(f.Fd()), uint32(lt), reserved, allBytes, allBytes, ol)
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if err != nil {
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return &fs.PathError{
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Op: lt.String(),
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Path: f.Name(),
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Err: err,
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}
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}
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return nil
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}
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func unlock(f File) error {
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ol := new(syscall.Overlapped)
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err := windows.UnlockFileEx(syscall.Handle(f.Fd()), reserved, allBytes, allBytes, ol)
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if err != nil {
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return &fs.PathError{
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Op: "Unlock",
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Path: f.Name(),
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Err: err,
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}
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}
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return nil
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}
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