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52 lines
1.1 KiB
Go
52 lines
1.1 KiB
Go
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// Copyright 2014 The LevelDB-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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// +build darwin dragonfly freebsd linux netbsd openbsd
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package filelock
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import (
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"io"
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"os"
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"syscall"
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)
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// lockCloser hides all of an os.File's methods, except for Close.
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type lockCloser struct {
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f *os.File
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}
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func (l lockCloser) Close() error {
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return l.f.Close()
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}
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func Lock(name string) (io.Closer, error) {
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f, err := os.Create(name)
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if err != nil {
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return nil, err
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}
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/*
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Some people tell me FcntlFlock does not exist, so use flock here
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*/
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if err := syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
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f.Close()
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return nil, err
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}
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// spec := syscall.Flock_t{
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// Type: syscall.F_WRLCK,
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// Whence: int16(os.SEEK_SET),
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// Start: 0,
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// Len: 0, // 0 means to lock the entire file.
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// Pid: int32(os.Getpid()),
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// }
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// if err := syscall.FcntlFlock(f.Fd(), syscall.F_SETLK, &spec); err != nil {
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// f.Close()
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// return nil, err
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// }
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return lockCloser{f}, nil
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}
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