fs

type File interface {
	io.Closer
	io.Reader
	io.ReaderAt
	io.Seeker
	io.Writer
	io.WriterAt

	Stat() (os.FileInfo, error)
	Sync() error
	Truncate(size int64) error

	Slice(start int64, end int64) ([]byte, error)
}

type FileSystem interface {
	OpenFile(name string, flag int, perm os.FileMode) (File, error)
	Stat(name string) (os.FileInfo, error)
	Remove(name string) error
	Rename(oldpath, newpath string) error
	ReadDir(name string) ([]os.FileInfo, error)

	CreateLockFile(name string, perm os.FileMode) (LockFile, bool, error)
}

type LockFile interface {
	Unlock() error
}