mirror of
https://github.com/golang/go
synced 2024-11-21 20:24:50 -07:00
io/ioutil: add TempFile
R=r CC=golang-dev https://golang.org/cl/1472042
This commit is contained in:
parent
47bc1f2e4b
commit
28852c1531
@ -7,5 +7,6 @@ include ../../../Make.$(GOARCH)
|
||||
TARG=io/ioutil
|
||||
GOFILES=\
|
||||
ioutil.go\
|
||||
tempfile.go\
|
||||
|
||||
include ../../../Make.pkg
|
||||
|
63
src/pkg/io/ioutil/tempfile.go
Normal file
63
src/pkg/io/ioutil/tempfile.go
Normal file
@ -0,0 +1,63 @@
|
||||
// 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 ioutil
|
||||
|
||||
import (
|
||||
"os"
|
||||
"strconv"
|
||||
)
|
||||
|
||||
// Random number state, accessed without lock; racy but harmless.
|
||||
// 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
|
||||
|
||||
func reseed() uint32 {
|
||||
sec, nsec, _ := os.Time()
|
||||
return uint32(sec*1e9 + nsec + int64(os.Getpid()))
|
||||
}
|
||||
|
||||
func nextSuffix() string {
|
||||
r := rand
|
||||
if r == 0 {
|
||||
r = reseed()
|
||||
}
|
||||
r = r*1664525 + 1013904223 // constants from Numerical Recipes
|
||||
rand = r
|
||||
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 value of the
|
||||
// environment variable $TMPDIR or, if that is empty,/tmp.
|
||||
// Multiple programs calling TempFile simultaneously
|
||||
// will not choose the same file. The caller can use f.Name()
|
||||
// to find the name of the file. It is the caller's responsibility to
|
||||
// remove the file when no longer needed.
|
||||
func TempFile(dir, prefix string) (f *os.File, err os.Error) {
|
||||
if dir == "" {
|
||||
dir = os.Getenv("TMPDIR")
|
||||
if dir == "" {
|
||||
dir = "/tmp"
|
||||
}
|
||||
}
|
||||
|
||||
nconflict := 0
|
||||
for i := 0; i < 10000; i++ {
|
||||
name := dir + "/" + prefix + nextSuffix()
|
||||
f, err = os.Open(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
|
||||
if pe, ok := err.(*os.PathError); ok && pe.Error == os.EEXIST {
|
||||
if nconflict++; nconflict > 10 {
|
||||
rand = reseed()
|
||||
}
|
||||
continue
|
||||
}
|
||||
break
|
||||
}
|
||||
return
|
||||
}
|
29
src/pkg/io/ioutil/tempfile_test.go
Normal file
29
src/pkg/io/ioutil/tempfile_test.go
Normal file
@ -0,0 +1,29 @@
|
||||
// Copyright 2010 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package ioutil_test
|
||||
|
||||
import (
|
||||
. "io/ioutil"
|
||||
"os"
|
||||
"testing"
|
||||
)
|
||||
|
||||
func TestTempFile(t *testing.T) {
|
||||
f, err := TempFile("/_not_exists_", "foo")
|
||||
if f != nil || err == nil {
|
||||
t.Errorf("TempFile(`/_not_exists_`, `foo`) = %v, %v", f, err)
|
||||
}
|
||||
|
||||
f, err = TempFile("/tmp", "ioutil_test")
|
||||
if f == nil || err != nil {
|
||||
t.Errorf("TempFile(`/tmp`, `ioutil_test`) = %v, %v", f, err)
|
||||
}
|
||||
re := testing.MustCompile("^/tmp/ioutil_test[0-9]+$")
|
||||
if !re.MatchString(f.Name()) {
|
||||
t.Fatalf("TempFile(`/tmp`, `ioutil_test`) created bad name %s", f.Name())
|
||||
}
|
||||
os.Remove(f.Name())
|
||||
f.Close()
|
||||
}
|
Loading…
Reference in New Issue
Block a user