}
	_, rawVal := input.Raw()

	if format != "json" {
		return nil, errDataSource(errors.New("path not supported"))
	}
	switch rec := rawVal.(type) {
	case jstream.KVS:
		txedRec, _, err := jsonpathEval(e.selectAST.From.Table.PathExpr[1:], rec)
		if err != nil {
			return nil, err
		}

		var kvs jstream.KVS
		switch v := txedRec.(type) {
		case jstream.KVS:
			kvs = v

	id           string     `msg:"id"`
	error        string     `msg:"err"`
	root         string     `msg:"root"`
	fileNotFound bool       `msg:"fnf"`
	status       scanStatus `msg:"stat"`
	recursive    bool       `msg:"rec"`
	dataVersion  uint8      `msg:"v"`
}

func (m *metacache) finished() bool {
	return !m.ended.IsZero()
}

// worthKeeping indicates if the cache by itself is worth keeping.