diff options
Diffstat (limited to 'gcc-4.7/libgo/go/io/ioutil/tempfile.go')
-rw-r--r-- | gcc-4.7/libgo/go/io/ioutil/tempfile.go | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/gcc-4.7/libgo/go/io/ioutil/tempfile.go b/gcc-4.7/libgo/go/io/ioutil/tempfile.go new file mode 100644 index 000000000..42d2e6758 --- /dev/null +++ b/gcc-4.7/libgo/go/io/ioutil/tempfile.go @@ -0,0 +1,91 @@ +// 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" + "path/filepath" + "strconv" + "time" +) + +// 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 { + return uint32(time.Now().UnixNano() + 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 error) { + if dir == "" { + dir = os.TempDir() + } + + nconflict := 0 + for i := 0; i < 10000; i++ { + name := filepath.Join(dir, prefix+nextSuffix()) + 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 +} + +// TempDir creates a new temporary directory in the directory dir +// with a name beginning with prefix and returns the path of the +// new directory. If dir is the empty string, TempDir uses the +// default directory for temporary files (see os.TempDir). +// Multiple programs calling TempDir simultaneously +// will not choose the same directory. It is the caller's responsibility +// to remove the directory when no longer needed. +func TempDir(dir, prefix string) (name string, err error) { + if dir == "" { + dir = os.TempDir() + } + + nconflict := 0 + for i := 0; i < 10000; i++ { + try := filepath.Join(dir, prefix+nextSuffix()) + err = os.Mkdir(try, 0700) + if os.IsExist(err) { + if nconflict++; nconflict > 10 { + rand = reseed() + } + continue + } + if err == nil { + name = try + } + break + } + return +} |