github.com/datastax/go-cassandra-native-protocol@v0.0.0-20220706104457-5e8aad05cf90/datatype/tuple.go (about)

     1  // Copyright 2020 DataStax
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package datatype
    16  
    17  import (
    18  	"bytes"
    19  	"fmt"
    20  	"io"
    21  
    22  	"github.com/datastax/go-cassandra-native-protocol/primitive"
    23  )
    24  
    25  // Tuple is a data type that represents a CQL tuple type.
    26  // +k8s:deepcopy-gen=true
    27  // +k8s:deepcopy-gen:interfaces=github.com/datastax/go-cassandra-native-protocol/datatype.DataType
    28  type Tuple struct {
    29  	FieldTypes []DataType
    30  }
    31  
    32  func NewTuple(fieldTypes ...DataType) *Tuple {
    33  	return &Tuple{FieldTypes: fieldTypes}
    34  }
    35  
    36  func (t *Tuple) Code() primitive.DataTypeCode {
    37  	return primitive.DataTypeCodeTuple
    38  }
    39  
    40  func (t *Tuple) String() string {
    41  	return t.AsCql()
    42  }
    43  
    44  func (t *Tuple) AsCql() string {
    45  	buf := &bytes.Buffer{}
    46  	buf.WriteString("tuple<")
    47  	for i, elementType := range t.FieldTypes {
    48  		if i > 0 {
    49  			buf.WriteString(",")
    50  		}
    51  		buf.WriteString(elementType.AsCql())
    52  	}
    53  	buf.WriteString(">")
    54  	return buf.String()
    55  }
    56  
    57  func writeTupleType(t DataType, dest io.Writer, version primitive.ProtocolVersion) (err error) {
    58  	tupleType, ok := t.(*Tuple)
    59  	if !ok {
    60  		return fmt.Errorf("expected *Tuple, got %T", t)
    61  	} else if err = primitive.WriteShort(uint16(len(tupleType.FieldTypes)), dest); err != nil {
    62  		return fmt.Errorf("cannot write tuple type field count: %w", err)
    63  	}
    64  	for i, fieldType := range tupleType.FieldTypes {
    65  		if err = WriteDataType(fieldType, dest, version); err != nil {
    66  			return fmt.Errorf("cannot write tuple field %d: %w", i, err)
    67  		}
    68  	}
    69  	return nil
    70  }
    71  
    72  func lengthOfTupleType(t DataType, version primitive.ProtocolVersion) (int, error) {
    73  	if tupleType, ok := t.(*Tuple); !ok {
    74  		return -1, fmt.Errorf("expected *Tuple, got %T", t)
    75  	} else {
    76  		length := primitive.LengthOfShort // field count
    77  		for i, fieldType := range tupleType.FieldTypes {
    78  			if fieldLength, err := LengthOfDataType(fieldType, version); err != nil {
    79  				return -1, fmt.Errorf("cannot compute length of tuple field %d: %w", i, err)
    80  			} else {
    81  				length += fieldLength
    82  			}
    83  		}
    84  		return length, nil
    85  	}
    86  }
    87  
    88  func readTupleType(source io.Reader, version primitive.ProtocolVersion) (DataType, error) {
    89  	if fieldCount, err := primitive.ReadShort(source); err != nil {
    90  		return nil, fmt.Errorf("cannot read tuple field count: %w", err)
    91  	} else {
    92  		tupleType := &Tuple{}
    93  		tupleType.FieldTypes = make([]DataType, fieldCount)
    94  		for i := 0; i < int(fieldCount); i++ {
    95  			if tupleType.FieldTypes[i], err = ReadDataType(source, version); err != nil {
    96  				return nil, fmt.Errorf("cannot read tuple field %d: %w", i, err)
    97  			}
    98  		}
    99  		return tupleType, nil
   100  	}
   101  }