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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/io/ioutil/tempfile.go
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Diffstat (limited to 'libgo/go/io/ioutil/tempfile.go')
-rw-r--r--libgo/go/io/ioutil/tempfile.go60
1 files changed, 60 insertions, 0 deletions
diff --git a/libgo/go/io/ioutil/tempfile.go b/libgo/go/io/ioutil/tempfile.go
new file mode 100644
index 000000000..114eca2b5
--- /dev/null
+++ b/libgo/go/io/ioutil/tempfile.go
@@ -0,0 +1,60 @@
+// 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 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 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.TempDir()
+ }
+
+ 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
+}