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
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
// Copyright 2010 The 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.
package generator
import (
"os"
"path/filepath"
"strconv"
"sync"
"time"
)
// Random number state.
// We generate random temporary file names so that there's a good
// chance the file doesn't exist yet - keeps the number of tries in
// TempFile to a minimum.
var rand uint32
var randmu sync.Mutex
func reseed() uint32 {
return uint32(time.Now().UnixNano() + int64(os.Getpid()))
}
func nextSuffix() string {
randmu.Lock()
r := rand
if r == 0 {
r = reseed()
}
r = r*1664525 + 1013904223 // constants from Numerical Recipes
rand = r
randmu.Unlock()
return strconv.Itoa(int(1e9 + r%1e9))[1:]
}
// TempFile creates a new temporary file in the directory dir
// with a name beginning with prefix, opens the file for reading
// and writing, and returns the resulting *os.File.
// If dir is the empty string, TempFile uses the default directory
// for temporary files (see os.TempDir).
// Multiple programs calling TempFile simultaneously
// will not choose the same file. The caller can use f.Name()
// to find the pathname of the file. It is the caller's responsibility
// to remove the file when no longer needed.
func TempFileWithPostfix(dir, prefix string, postfix string) (f *os.File, err error) {
if dir == "" {
dir = os.TempDir()
}
nconflict := 0
for i := 0; i < 10000; i++ {
name := filepath.Join(dir, prefix+nextSuffix()+postfix)
f, err = os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
if os.IsExist(err) {
if nconflict++; nconflict > 10 {
rand = reseed()
}
continue
}
break
}
return
}
|
