github.com/insionng/yougam@v0.0.0-20170714101924-2bc18d833463/libraries/syndtr/goleveldb/leveldb/storage/file_storage_unix.go (about) 1 // Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com> 2 // All rights reserved. 3 // 4 // Use of this source code is governed by a BSD-style license that can be 5 // found in the LICENSE file. 6 7 // +build darwin dragonfly freebsd linux netbsd openbsd 8 9 package storage 10 11 import ( 12 "os" 13 "syscall" 14 ) 15 16 type unixFileLock struct { 17 f *os.File 18 } 19 20 func (fl *unixFileLock) release() error { 21 if err := setFileLock(fl.f, false, false); err != nil { 22 return err 23 } 24 return fl.f.Close() 25 } 26 27 func newFileLock(path string, readOnly bool) (fl fileLock, err error) { 28 var flag int 29 if readOnly { 30 flag = os.O_RDONLY 31 } else { 32 flag = os.O_RDWR 33 } 34 f, err := os.OpenFile(path, flag, 0) 35 if os.IsNotExist(err) { 36 f, err = os.OpenFile(path, flag|os.O_CREATE, 0644) 37 } 38 if err != nil { 39 return 40 } 41 err = setFileLock(f, readOnly, true) 42 if err != nil { 43 f.Close() 44 return 45 } 46 fl = &unixFileLock{f: f} 47 return 48 } 49 50 func setFileLock(f *os.File, readOnly, lock bool) error { 51 how := syscall.LOCK_UN 52 if lock { 53 if readOnly { 54 how = syscall.LOCK_SH 55 } else { 56 how = syscall.LOCK_EX 57 } 58 } 59 return syscall.Flock(int(f.Fd()), how|syscall.LOCK_NB) 60 } 61 62 func rename(oldpath, newpath string) error { 63 return os.Rename(oldpath, newpath) 64 } 65 66 func isErrInvalid(err error) bool { 67 if err == os.ErrInvalid { 68 return true 69 } 70 if syserr, ok := err.(*os.SyscallError); ok && syserr.Err == syscall.EINVAL { 71 return true 72 } 73 return false 74 } 75 76 func syncDir(name string) error { 77 f, err := os.Open(name) 78 if err != nil { 79 return err 80 } 81 defer f.Close() 82 if err := f.Sync(); err != nil && !isErrInvalid(err) { 83 return err 84 } 85 return nil 86 }