/
tmpdir.go
104 lines (91 loc) · 2.13 KB
/
tmpdir.go
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/*
Copyright 2021 Flant JSC
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package hooks
import (
"os"
"path/filepath"
"strconv"
"strings"
"sync"
"time"
)
var rand uint32
var randmu sync.Mutex
func reseed() uint32 {
return uint32(time.Now().UnixNano() + int64(os.Getpid()))
}
func nextRandom() 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:]
}
func TempFileWithPerms(dir, pattern string, perms int) (f *os.File, err error) {
if dir == "" {
dir = os.TempDir()
}
var prefix, suffix string
if pos := strings.LastIndex(pattern, "*"); pos != -1 {
prefix, suffix = pattern[:pos], pattern[pos+1:]
} else {
prefix = pattern
}
nconflict := 0
for i := 0; i < 10000; i++ {
name := filepath.Join(dir, prefix+nextRandom()+suffix)
f, err = os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, os.FileMode(perms))
if os.IsExist(err) {
if nconflict++; nconflict > 10 {
randmu.Lock()
rand = reseed()
randmu.Unlock()
}
continue
}
break
}
return
}
func TempDirWithPerms(dir, prefix string, perms int) (name string, err error) {
if dir == "" {
dir = os.TempDir()
}
nconflict := 0
for i := 0; i < 10000; i++ {
try := filepath.Join(dir, prefix+nextRandom())
err = os.Mkdir(try, os.FileMode(perms))
if os.IsExist(err) {
if nconflict++; nconflict > 10 {
randmu.Lock()
rand = reseed()
randmu.Unlock()
}
continue
}
if os.IsNotExist(err) {
if _, err := os.Stat(dir); os.IsNotExist(err) {
return "", err
}
}
if err == nil {
name = try
}
break
}
return
}