func writeTarFromLayer(r hcsshim.LayerReader, w io.Writer) error {
t := tar.NewWriter(w)
for {
name, size, fileInfo, err := r.Next()
if err == io.EOF {
break
}
if err != nil {
return err
}
if fileInfo == nil {
// Write a whiteout file.
hdr := &tar.Header{
Name: filepath.ToSlash(filepath.Join(filepath.Dir(name), archive.WhiteoutPrefix+filepath.Base(name))),
}
err := t.WriteHeader(hdr)
if err != nil {
return err
}
} else {
err = backuptar.WriteTarFileFromBackupStream(t, r, name, size, fileInfo)
if err != nil {
return err
}
}
}
return t.Close()
}
