code: func RecoverFile(path string, o *opt.Options) (db *DB, err error) {
  	stor, err := storage.OpenFile(path, false)
  	if err != nil {
  		return
  	}
  	db, err = Recover(stor, o)
  	if err != nil {
  		stor.Close()
  	} else {
  		db.closer = stor
  	}
  	return
  }
docs: // RecoverFile recovers and opens a DB with missing or corrupted manifest files
  // for the given path. It will ignore any manifest files, valid or not.
  // The DB must already exist or it will returns an error.
  // Also, Recover will ignore ErrorIfMissing and ErrorIfExist options.
  //
  // RecoverFile uses standard file-system backed storage implementation as described
  // in the leveldb/storage package.
  //
  // The returned DB instance is safe for concurrent use.
  // The DB must be closed after use, by calling Close method.