Golang parser.DBytes函數代碼示例

// Arg implements the parser.Args interface.
func (p parameters) Arg(name string) (parser.Datum, bool) {
	i, err := processPositionalArgument(name)
	if err != nil {
		return nil, false
	}
	if i < 1 || int(i) > len(p) {
		return nil, false
	}
	arg := p[i-1].Payload
	if arg == nil {
		return parser.DNull, true
	}
	switch t := arg.(type) {
	case *driver.Datum_BoolVal:
		return parser.DBool(t.BoolVal), true
	case *driver.Datum_IntVal:
		return parser.DInt(t.IntVal), true
	case *driver.Datum_FloatVal:
		return parser.DFloat(t.FloatVal), true
	case *driver.Datum_BytesVal:
		return parser.DBytes(t.BytesVal), true
	case *driver.Datum_StringVal:
		return parser.DString(t.StringVal), true
	case *driver.Datum_DateVal:
		return parser.DDate(t.DateVal), true
	case *driver.Datum_TimeVal:
		return parser.DTimestamp{Time: t.TimeVal.GoTime()}, true
	case *driver.Datum_IntervalVal:
		return parser.DInterval{Duration: time.Duration(t.IntervalVal)}, true
	default:
		panic(fmt.Sprintf("unexpected type %T", t))
	}
}

func datumFromProto(d driver.Datum) parser.Datum {
	arg := d.Payload
	if arg == nil {
		return parser.DNull
	}
	switch t := arg.(type) {
	case *driver.Datum_BoolVal:
		return parser.DBool(t.BoolVal)
	case *driver.Datum_IntVal:
		return parser.DInt(t.IntVal)
	case *driver.Datum_FloatVal:
		return parser.DFloat(t.FloatVal)
	case *driver.Datum_DecimalVal:
		dec, err := decimal.NewFromString(t.DecimalVal)
		if err != nil {
			panic(fmt.Sprintf("could not parse decimal: %v", err))
		}
		return parser.DDecimal{Decimal: dec}
	case *driver.Datum_BytesVal:
		return parser.DBytes(t.BytesVal)
	case *driver.Datum_StringVal:
		return parser.DString(t.StringVal)
	case *driver.Datum_DateVal:
		return parser.DDate(t.DateVal)
	case *driver.Datum_TimeVal:
		return parser.DTimestamp{Time: t.TimeVal.GoTime()}
	case *driver.Datum_IntervalVal:
		return parser.DInterval{Duration: time.Duration(t.IntervalVal)}
	default:
		panic(fmt.Sprintf("unexpected type %T", t))
	}
}

func decodeTableKey(valType parser.Datum, key []byte) (parser.Datum, []byte, error) {
	var isNull bool
	if key, isNull = encoding.DecodeIfNull(key); isNull {
		return parser.DNull, key, nil
	}
	switch valType.(type) {
	case parser.DBool:
		rkey, i, err := encoding.DecodeVarint(key)
		return parser.DBool(i != 0), rkey, err
	case parser.DInt:
		rkey, i, err := encoding.DecodeVarint(key)
		return parser.DInt(i), rkey, err
	case parser.DFloat:
		rkey, f, err := encoding.DecodeFloat(key, nil)
		return parser.DFloat(f), rkey, err
	case parser.DString:
		rkey, r, err := encoding.DecodeString(key, nil)
		return parser.DString(r), rkey, err
	case parser.DBytes:
		rkey, r, err := encoding.DecodeString(key, nil)
		return parser.DBytes(r), rkey, err
	case parser.DDate:
		rkey, t, err := encoding.DecodeTime(key)
		return parser.DDate{Time: t}, rkey, err
	case parser.DTimestamp:
		rkey, t, err := encoding.DecodeTime(key)
		return parser.DTimestamp{Time: t}, rkey, err
	case parser.DInterval:
		rkey, d, err := encoding.DecodeVarint(key)
		return parser.DInterval{Duration: time.Duration(d)}, rkey, err
	default:
		return nil, nil, util.Errorf("TODO(pmattis): decoded index key: %s", valType.Type())
	}
}

func datumFromProto(d driver.Datum) parser.Datum {
	arg := d.Payload
	if arg == nil {
		return parser.DNull
	}
	switch t := arg.(type) {
	case *driver.Datum_BoolVal:
		return parser.DBool(t.BoolVal)
	case *driver.Datum_IntVal:
		return parser.DInt(t.IntVal)
	case *driver.Datum_FloatVal:
		return parser.DFloat(t.FloatVal)
	case *driver.Datum_DecimalVal:
		dd := &parser.DDecimal{}
		if _, ok := dd.SetString(t.DecimalVal); !ok {
			panic(fmt.Sprintf("could not parse string %q as decimal", t.DecimalVal))
		}
		return dd
	case *driver.Datum_BytesVal:
		return parser.DBytes(t.BytesVal)
	case *driver.Datum_StringVal:
		return parser.DString(t.StringVal)
	case *driver.Datum_DateVal:
		return parser.DDate(t.DateVal)
	case *driver.Datum_TimeVal:
		return parser.DTimestamp{Time: t.TimeVal.GoTime()}
	case *driver.Datum_IntervalVal:
		return parser.DInterval{Duration: time.Duration(t.IntervalVal)}
	default:
		panic(fmt.Sprintf("unexpected type %T", t))
	}
}

// unmarshalColumnValue decodes the value from a key-value pair using the type
// expected by the column. An error is returned if the value's type does not
// match the column's type.
func unmarshalColumnValue(kind ColumnType_Kind, value *proto.Value) (parser.Datum, error) {
	if value == nil {
		return parser.DNull, nil
	}

	switch kind {
	case ColumnType_BOOL:
		v, err := value.GetInt()
		if err != nil {
			return nil, err
		}
		return parser.DBool(v != 0), nil
	case ColumnType_INT:
		v, err := value.GetInt()
		if err != nil {
			return nil, err
		}
		return parser.DInt(v), nil
	case ColumnType_FLOAT:
		v, err := value.GetFloat()
		if err != nil {
			return nil, err
		}
		return parser.DFloat(v), nil
	case ColumnType_STRING:
		v, err := value.GetBytesChecked()
		if err != nil {
			return nil, err
		}
		return parser.DString(v), nil
	case ColumnType_BYTES:
		v, err := value.GetBytesChecked()
		if err != nil {
			return nil, err
		}
		return parser.DBytes(v), nil
	case ColumnType_DATE:
		v, err := value.GetTime()
		if err != nil {
			return nil, err
		}
		return parser.DDate{Time: v}, nil
	case ColumnType_TIMESTAMP:
		v, err := value.GetTime()
		if err != nil {
			return nil, err
		}
		return parser.DTimestamp{Time: v}, nil
	case ColumnType_INTERVAL:
		v, err := value.GetInt()
		if err != nil {
			return nil, err
		}
		return parser.DInterval{Duration: time.Duration(v)}, nil
	default:
		return nil, util.Errorf("unsupported column type: %s", kind)
	}
}

// DecodeTableValue decodes a value encoded by EncodeTableValue.
func DecodeTableValue(a *DatumAlloc, valType parser.Datum, b []byte) (parser.Datum, []byte, error) {
	// TODO(dan): Merge this and DecodeTableKey.
	if len(b) == 0 {
		return nil, nil, util.Errorf("empty slice")
	}
	if roachpb.ValueType(b[0]) == roachpb.ValueType_NULL {
		return parser.DNull, b[1:], nil
	}
	var err error
	switch valType.(type) {
	case *parser.DBool:
		var i int64
		b, i, err = roachpb.DecodeIntValue(b)
		// No need to chunk allocate DBool as MakeDBool returns either
		// parser.DBoolTrue or parser.DBoolFalse.
		return parser.MakeDBool(parser.DBool(i != 0)), b, err
	case *parser.DInt:
		var i int64
		b, i, err = roachpb.DecodeIntValue(b)
		return a.NewDInt(parser.DInt(i)), b, err
	case *parser.DFloat:
		var f float64
		b, f, err = roachpb.DecodeFloatValue(b)
		return a.NewDFloat(parser.DFloat(f)), b, err
	case *parser.DDecimal:
		var d *inf.Dec
		b, d, err = roachpb.DecodeDecimalValue(b)
		dd := a.NewDDecimal(parser.DDecimal{})
		dd.Set(d)
		return dd, b, err
	case *parser.DString:
		var data []byte
		b, data, err = roachpb.DecodeBytesValue(b)
		return a.NewDString(parser.DString(data)), b, err
	case *parser.DBytes:
		var data []byte
		b, data, err = roachpb.DecodeBytesValue(b)
		return a.NewDBytes(parser.DBytes(data)), b, err
	case *parser.DDate:
		var i int64
		b, i, err = roachpb.DecodeIntValue(b)
		return a.NewDDate(parser.DDate(i)), b, err
	case *parser.DTimestamp:
		var t time.Time
		b, t, err = roachpb.DecodeTimeValue(b)
		return a.NewDTimestamp(parser.DTimestamp{Time: t}), b, err
	case *parser.DTimestampTZ:
		var t time.Time
		b, t, err = roachpb.DecodeTimeValue(b)
		return a.NewDTimestampTZ(parser.DTimestampTZ{Time: t}), b, err
	case *parser.DInterval:
		var d duration.Duration
		b, d, err = roachpb.DecodeDurationValue(b)
		return a.NewDInterval(parser.DInterval{Duration: d}), b, err
	default:
		return nil, nil, util.Errorf("TODO(pmattis): decoded index value: %s", valType.Type())
	}
}

// DecodeTableValue decodes a value encoded by EncodeTableValue.
func DecodeTableValue(a *DatumAlloc, valType parser.Datum, b []byte) (parser.Datum, []byte, error) {
	_, dataOffset, _, typ, err := encoding.DecodeValueTag(b)
	if err != nil {
		return nil, b, err
	}
	if typ == encoding.Null {
		return parser.DNull, b[dataOffset:], nil
	}
	switch valType.(type) {
	case *parser.DBool:
		var x bool
		b, x, err = encoding.DecodeBoolValue(b)
		// No need to chunk allocate DBool as MakeDBool returns either
		// parser.DBoolTrue or parser.DBoolFalse.
		return parser.MakeDBool(parser.DBool(x)), b, err
	case *parser.DInt:
		var i int64
		b, i, err = encoding.DecodeIntValue(b)
		return a.NewDInt(parser.DInt(i)), b, err
	case *parser.DFloat:
		var f float64
		b, f, err = encoding.DecodeFloatValue(b)
		return a.NewDFloat(parser.DFloat(f)), b, err
	case *parser.DDecimal:
		var d *inf.Dec
		b, d, err = encoding.DecodeDecimalValue(b)
		dd := a.NewDDecimal(parser.DDecimal{})
		dd.Set(d)
		return dd, b, err
	case *parser.DString:
		var data []byte
		b, data, err = encoding.DecodeBytesValue(b)
		return a.NewDString(parser.DString(data)), b, err
	case *parser.DBytes:
		var data []byte
		b, data, err = encoding.DecodeBytesValue(b)
		return a.NewDBytes(parser.DBytes(data)), b, err
	case *parser.DDate:
		var i int64
		b, i, err = encoding.DecodeIntValue(b)
		return a.NewDDate(parser.DDate(i)), b, err
	case *parser.DTimestamp:
		var t time.Time
		b, t, err = encoding.DecodeTimeValue(b)
		return a.NewDTimestamp(parser.DTimestamp{Time: t}), b, err
	case *parser.DTimestampTZ:
		var t time.Time
		b, t, err = encoding.DecodeTimeValue(b)
		return a.NewDTimestampTZ(parser.DTimestampTZ{Time: t}), b, err
	case *parser.DInterval:
		var d duration.Duration
		b, d, err = encoding.DecodeDurationValue(b)
		return a.NewDInterval(parser.DInterval{Duration: d}), b, err
	default:
		return nil, nil, errors.Errorf("TODO(pmattis): decoded index value: %s", valType.Type())
	}
}

// golangFillQueryArguments populates the placeholder map with
// types and values from an array of Go values.
// TODO: This does not support arguments of the SQL 'Date' type, as there is not
// an equivalent type in Go's standard library. It's not currently needed by any
// of our internal tables.
func golangFillQueryArguments(pinfo *parser.PlaceholderInfo, args []interface{}) {
	pinfo.Clear()

	for i, arg := range args {
		k := fmt.Sprint(i + 1)
		if arg == nil {
			pinfo.SetValue(k, parser.DNull)
			continue
		}

		// A type switch to handle a few explicit types with special semantics:
		// - Datums are passed along as is.
		// - Time datatypes get special representation in the database.
		var d parser.Datum
		switch t := arg.(type) {
		case parser.Datum:
			d = t
		case time.Time:
			d = parser.MakeDTimestamp(t, time.Microsecond)
		case time.Duration:
			d = &parser.DInterval{Duration: duration.Duration{Nanos: t.Nanoseconds()}}
		case *inf.Dec:
			dd := &parser.DDecimal{}
			dd.Set(t)
			d = dd
		}
		if d == nil {
			// Handle all types which have an underlying type that can be stored in the
			// database.
			// Note: if this reflection becomes a performance concern in the future,
			// commonly used types could be added explicitly into the type switch above
			// for a performance gain.
			val := reflect.ValueOf(arg)
			switch val.Kind() {
			case reflect.Bool:
				d = parser.MakeDBool(parser.DBool(val.Bool()))
			case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
				d = parser.NewDInt(parser.DInt(val.Int()))
			case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
				d = parser.NewDInt(parser.DInt(val.Uint()))
			case reflect.Float32, reflect.Float64:
				d = parser.NewDFloat(parser.DFloat(val.Float()))
			case reflect.String:
				d = parser.NewDString(val.String())
			case reflect.Slice:
				// Handle byte slices.
				if val.Type().Elem().Kind() == reflect.Uint8 {
					d = parser.NewDBytes(parser.DBytes(val.Bytes()))
				}
			}
			if d == nil {
				panic(fmt.Sprintf("unexpected type %T", arg))
			}
		}
		pinfo.SetValue(k, d)
	}
}

// SetUIData is an endpoint that sets the data associated with a key.
func (s *adminServer) SetUIData(_ context.Context, req *SetUIDataRequest) (*SetUIDataResponse, error) {
	if len(req.Key) == 0 {
		return nil, grpc.Errorf(codes.InvalidArgument, "key cannot be empty")
	}

	var session sql.Session
	user := s.getUser(req)

	// Do an upsert of the key.
	br := s.sqlExecutor.ExecuteStatements(user, &session, "BEGIN;", nil)
	if err := s.checkQueryResults(br.ResultList, 1); err != nil {
		return nil, s.serverError(err)
	}

	// See if the key already exists.
	alreadyExists := true
	if _, _, err := s.getUIData(&session, user, req.Key); err != nil {
		if err != errUIKeyNotFound {
			return nil, s.serverError(err)
		}
		alreadyExists = false
	}

	// INSERT or UPDATE as appropriate.
	ts := session.Txn.TxnTimestamp
	if alreadyExists {
		query := "UPDATE system.ui SET value = $1, lastUpdated = $2 WHERE key = $3; COMMIT;"
		params := []parser.Datum{
			parser.DString(req.Value),            // $1
			parser.DTimestamp{Time: ts.GoTime()}, // $2
			parser.DString(req.Key),              // $3
		}
		r := s.sqlExecutor.ExecuteStatements(user, &session, query, params)
		if err := s.checkQueryResults(r.ResultList, 2); err != nil {
			return nil, s.serverError(err)
		}
		if a, e := r.ResultList[0].RowsAffected, 1; a != e {
			return nil, s.serverErrorf("rows affected %d != expected %d", a, e)
		}
	} else {
		query := "INSERT INTO system.ui (key, value, lastUpdated) VALUES ($1, $2, $3); COMMIT;"
		params := []parser.Datum{
			parser.DString(req.Key),              // $1
			parser.DBytes(req.Value),             // $2
			parser.DTimestamp{Time: ts.GoTime()}, // $3
		}
		r := s.sqlExecutor.ExecuteStatements(user, &session, query, params)
		if err := s.checkQueryResults(r.ResultList, 2); err != nil {
			return nil, s.serverError(err)
		}
		if a, e := r.ResultList[0].RowsAffected, 1; a != e {
			return nil, s.serverErrorf("rows affected %d != expected %d", a, e)
		}
	}

	return &SetUIDataResponse{}, nil
}

// Arg implements the parser.Args interface.
// TODO: This does not support arguments of the SQL 'Date' type, as there is not
// an equivalent type in Go's standard library. It's not currently needed by any
// of our internal tables.
func (gp golangParameters) Arg(name string) (parser.Datum, bool) {
	i, err := processPositionalArgument(name)
	if err != nil {
		return nil, false
	}
	if i < 1 || int(i) > len(gp) {
		return nil, false
	}
	arg := gp[i-1]
	if arg == nil {
		return parser.DNull, true
	}

	// A type switch to handle a few explicit types with special semantics.
	switch t := arg.(type) {
	// Datums are passed along as is.
	case parser.Datum:
		return t, true
	// Time datatypes get special representation in the database.
	case time.Time:
		return parser.DTimestamp{Time: t}, true
	case time.Duration:
		return parser.DInterval{Duration: t}, true
	case *inf.Dec:
		dd := &parser.DDecimal{}
		dd.Set(t)
		return dd, true
	}

	// Handle all types which have an underlying type that can be stored in the
	// database.
	// Note: if this reflection becomes a performance concern in the future,
	// commonly used types could be added explicitly into the type switch above
	// for a performance gain.
	val := reflect.ValueOf(arg)
	switch val.Kind() {
	case reflect.Bool:
		return parser.DBool(val.Bool()), true
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return parser.DInt(val.Int()), true
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		return parser.DInt(val.Uint()), true
	case reflect.Float32, reflect.Float64:
		return parser.DFloat(val.Float()), true
	case reflect.String:
		return parser.DString(val.String()), true
	case reflect.Slice:
		// Handle byte slices.
		if val.Type().Elem().Kind() == reflect.Uint8 {
			return parser.DBytes(val.Bytes()), true
		}
	}

	panic(fmt.Sprintf("unexpected type %T", arg))
}

// SetUIData is an endpoint that stores the given key/value pairs in the
// system.ui table. See GetUIData for more details on semantics.
func (s *adminServer) SetUIData(ctx context.Context, req *SetUIDataRequest) (*SetUIDataResponse, error) {
	if len(req.KeyValues) == 0 {
		return nil, grpc.Errorf(codes.InvalidArgument, "KeyValues cannot be empty")
	}

	session := sql.NewSession(sql.SessionArgs{User: s.getUser(req)}, s.sqlExecutor, nil)

	for key, val := range req.KeyValues {
		// Do an upsert of the key. We update each key in a separate transaction to
		// avoid long-running transactions and possible deadlocks.
		br := s.sqlExecutor.ExecuteStatements(ctx, session, "BEGIN;", nil)
		if err := s.checkQueryResults(br.ResultList, 1); err != nil {
			return nil, s.serverError(err)
		}

		// See if the key already exists.
		resp, err := s.getUIData(session, s.getUser(req), []string{key})
		if err != nil {
			return nil, s.serverError(err)
		}
		_, alreadyExists := resp.KeyValues[key]

		// INSERT or UPDATE as appropriate.
		if alreadyExists {
			query := "UPDATE system.ui SET value = $1, lastUpdated = NOW() WHERE key = $2; COMMIT;"
			params := []parser.Datum{
				parser.DString(val), // $1
				parser.DString(key), // $2
			}
			r := s.sqlExecutor.ExecuteStatements(ctx, session, query, params)
			if err := s.checkQueryResults(r.ResultList, 2); err != nil {
				return nil, s.serverError(err)
			}
			if a, e := r.ResultList[0].RowsAffected, 1; a != e {
				return nil, s.serverErrorf("rows affected %d != expected %d", a, e)
			}
		} else {
			query := "INSERT INTO system.ui (key, value, lastUpdated) VALUES ($1, $2, NOW()); COMMIT;"
			params := []parser.Datum{
				parser.DString(key), // $1
				parser.DBytes(val),  // $2
			}
			r := s.sqlExecutor.ExecuteStatements(ctx, session, query, params)
			if err := s.checkQueryResults(r.ResultList, 2); err != nil {
				return nil, s.serverError(err)
			}
			if a, e := r.ResultList[0].RowsAffected, 1; a != e {
				return nil, s.serverErrorf("rows affected %d != expected %d", a, e)
			}
		}
	}

	return &SetUIDataResponse{}, nil
}

// Arg implements the parser.Args interface.
func (p parameters) Arg(name string) (parser.Datum, bool) {
	if len(name) == 0 {
		// This shouldn't happen unless the parser let through an invalid parameter
		// specification.
		panic(fmt.Sprintf("invalid empty parameter name"))
	}
	if ch := name[0]; ch < '0' || ch > '9' {
		// TODO(pmattis): Add support for named parameters (vs the numbered
		// parameter support below).
		return nil, false
	}
	i, err := strconv.ParseInt(name, 10, 0)
	if err != nil {
		return nil, false
	}
	if i < 1 || int(i) > len(p) {
		return nil, false
	}
	arg := p[i-1].Payload
	if arg == nil {
		return parser.DNull, true
	}
	switch t := arg.(type) {
	case *driver.Datum_BoolVal:
		return parser.DBool(t.BoolVal), true
	case *driver.Datum_IntVal:
		return parser.DInt(t.IntVal), true
	case *driver.Datum_FloatVal:
		return parser.DFloat(t.FloatVal), true
	case *driver.Datum_BytesVal:
		return parser.DBytes(t.BytesVal), true
	case *driver.Datum_StringVal:
		return parser.DString(t.StringVal), true
	case *driver.Datum_DateVal:
		return parser.DDate(t.DateVal), true
	case *driver.Datum_TimeVal:
		return parser.DTimestamp{Time: t.TimeVal.GoTime()}, true
	case *driver.Datum_IntervalVal:
		return parser.DInterval{Duration: time.Duration(t.IntervalVal)}, true
	default:
		panic(fmt.Sprintf("unexpected type %T", t))
	}
}

// RandDatum generates a random Datum of the given type.
// If null is true, the datum can be DNull.
func RandDatum(rng *rand.Rand, typ ColumnType_Kind, null bool) parser.Datum {
	if null && rng.Intn(10) == 0 {
		return parser.DNull
	}
	switch typ {
	case ColumnType_BOOL:
		return parser.MakeDBool(rng.Intn(2) == 1)
	case ColumnType_INT:
		return parser.NewDInt(parser.DInt(rng.Int63()))
	case ColumnType_FLOAT:
		return parser.NewDFloat(parser.DFloat(rng.NormFloat64()))
	case ColumnType_DECIMAL:
		d := &parser.DDecimal{}
		d.Dec.SetScale(inf.Scale(rng.Intn(40) - 20))
		d.Dec.SetUnscaled(rng.Int63())
		return d
	case ColumnType_DATE:
		return parser.NewDDate(parser.DDate(rng.Intn(10000)))
	case ColumnType_TIMESTAMP:
		return &parser.DTimestamp{Time: time.Unix(rng.Int63n(1000000), rng.Int63n(1000000))}
	case ColumnType_INTERVAL:
		return &parser.DInterval{Duration: duration.Duration{Months: rng.Int63n(1000),
			Days:  rng.Int63n(1000),
			Nanos: rng.Int63n(1000000),
		}}
	case ColumnType_STRING:
		// Generate a random ASCII string.
		p := make([]byte, rng.Intn(10))
		for i := range p {
			p[i] = byte(1 + rng.Intn(127))
		}
		return parser.NewDString(string(p))
	case ColumnType_BYTES:
		p := make([]byte, rng.Intn(10))
		_, _ = rng.Read(p)
		return parser.NewDBytes(parser.DBytes(p))
	case ColumnType_TIMESTAMPTZ:
		return &parser.DTimestampTZ{Time: time.Unix(rng.Int63n(1000000), rng.Int63n(1000000))}
	default:
		panic(fmt.Sprintf("invalid type %s", typ))
	}
}

// Arg implements the parser.Args interface.
func (p parameters) Arg(name string) (parser.Datum, bool) {
	if len(name) == 0 {
		// This shouldn't happen unless the parser let through an invalid parameter
		// specification.
		panic(fmt.Sprintf("invalid empty parameter name"))
	}
	if ch := name[0]; ch < '0' || ch > '9' {
		// TODO(pmattis): Add support for named parameters (vs the numbered
		// parameter support below).
		return nil, false
	}
	i, err := strconv.ParseInt(name, 10, 0)
	if err != nil {
		return nil, false
	}
	if i < 1 || int(i) > len(p) {
		return nil, false
	}
	arg := p[i-1].GetValue()
	if arg == nil {
		return parser.DNull, true
	}
	switch t := arg.(type) {
	case *bool:
		return parser.DBool(*t), true
	case *int64:
		return parser.DInt(*t), true
	case *float64:
		return parser.DFloat(*t), true
	case []byte:
		return parser.DBytes(t), true
	case *string:
		return parser.DString(*t), true
	case *driver.Datum_Timestamp:
		return parser.DTimestamp{Time: time.Unix((*t).Sec, int64((*t).Nsec)).UTC()}, true
	default:
		panic(fmt.Sprintf("unexpected type %T", t))
	}
}

func (n *scanNode) unmarshalValue(kv client.KeyValue) (parser.Datum, bool) {
	kind, ok := n.colKind[n.colID]
	if !ok {
		n.err = fmt.Errorf("column-id \"%d\" does not exist", n.colID)
		return nil, false
	}
	if kv.Exists() {
		switch kind {
		case ColumnType_INT:
			return parser.DInt(kv.ValueInt()), true
		case ColumnType_BOOL:
			return parser.DBool(kv.ValueInt() != 0), true
		case ColumnType_FLOAT:
			return parser.DFloat(math.Float64frombits(uint64(kv.ValueInt()))), true
		case ColumnType_STRING:
			return parser.DString(kv.ValueBytes()), true
		case ColumnType_BYTES:
			return parser.DBytes(kv.ValueBytes()), true
		case ColumnType_DATE:
			var t time.Time
			if err := t.UnmarshalBinary(kv.ValueBytes()); err != nil {
				return nil, false
			}
			return parser.DDate{Time: t}, true
		case ColumnType_TIMESTAMP:
			var t time.Time
			if err := t.UnmarshalBinary(kv.ValueBytes()); err != nil {
				return nil, false
			}
			return parser.DTimestamp{Time: t}, true
		case ColumnType_INTERVAL:
			return parser.DInterval{Duration: time.Duration(kv.ValueInt())}, true
		}
	}
	return parser.DNull, true
}