1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
// 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 solaris
package db
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 (defFS) Lock(name string) (io.Closer, error) {
f, err := os.Create(name)
if err != nil {
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
}
|
