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Beego/vendor/github.com/siddontang/go/filelock/file_lock_unix.go
2018-11-09 12:37:28 +08:00

52 lines
1.1 KiB
Go

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