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khenaidooab1f7bd2019-11-14 14:00:27 -05001// Copyright 2015 The etcd Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package ioutil
16
17import (
18 "io"
19 "os"
20
21 "go.etcd.io/etcd/pkg/fileutil"
22)
23
24// WriteAndSyncFile behaves just like ioutil.WriteFile in the standard library,
25// but calls Sync before closing the file. WriteAndSyncFile guarantees the data
26// is synced if there is no error returned.
27func WriteAndSyncFile(filename string, data []byte, perm os.FileMode) error {
28 f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
29 if err != nil {
30 return err
31 }
32 n, err := f.Write(data)
33 if err == nil && n < len(data) {
34 err = io.ErrShortWrite
35 }
36 if err == nil {
37 err = fileutil.Fsync(f)
38 }
39 if err1 := f.Close(); err == nil {
40 err = err1
41 }
42 return err
43}