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package atomic
import (
"io"
"io/ioutil"
"os"
"path"
)
// WriteFileReader writes data from a reader atomically into filename.
func WriteFileReader(filename string, r io.Reader, perm os.FileMode) error {
dir, name := path.Split(filename)
f, err := ioutil.TempFile(dir, name)
if err != nil {
return err
}
_, err = io.Copy(f, r)
if err == nil {
err = f.Sync()
}
if closeErr := f.Close(); err == nil {
err = closeErr
}
if permErr := os.Chmod(f.Name(), perm); err == nil {
err = permErr
}
if err == nil {
err = os.Rename(f.Name(), filename)
}
// Any err should result in full cleanup.
if err != nil {
os.Remove(f.Name())
}
return err
}
// WriteFileAtomic writes the data to a temp file and atomically move if
// everything else succeeds.
func WriteFile(filename string, data []byte, perm os.FileMode) error {
dir, name := path.Split(filename)
f, err := ioutil.TempFile(dir, name)
if err != nil {
return err
}
_, err = f.Write(data)
if err == nil {
err = f.Sync()
}
if closeErr := f.Close(); err == nil {
err = closeErr
}
if permErr := os.Chmod(f.Name(), perm); err == nil {
err = permErr
}
if err == nil {
err = os.Rename(f.Name(), filename)
}
// Any err should result in full cleanup.
if err != nil {
os.Remove(f.Name())
}
return err
}
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