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package pgproto3
import (
"bytes"
"encoding/binary"
"encoding/json"
"errors"
"math"
"github.com/jackc/pgx/v5/internal/pgio"
)
const (
TextFormat = 0
BinaryFormat = 1
)
type FieldDescription struct {
Name []byte
TableOID uint32
TableAttributeNumber uint16
DataTypeOID uint32
DataTypeSize int16
TypeModifier int32
Format int16
}
// MarshalJSON implements encoding/json.Marshaler.
func (fd FieldDescription) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
Name string
TableOID uint32
TableAttributeNumber uint16
DataTypeOID uint32
DataTypeSize int16
TypeModifier int32
Format int16
}{
Name: string(fd.Name),
TableOID: fd.TableOID,
TableAttributeNumber: fd.TableAttributeNumber,
DataTypeOID: fd.DataTypeOID,
DataTypeSize: fd.DataTypeSize,
TypeModifier: fd.TypeModifier,
Format: fd.Format,
})
}
type RowDescription struct {
Fields []FieldDescription
}
// Backend identifies this message as sendable by the PostgreSQL backend.
func (*RowDescription) Backend() {}
// Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message
// type identifier and 4 byte message length.
func (dst *RowDescription) Decode(src []byte) error {
if len(src) < 2 {
return &invalidMessageFormatErr{messageType: "RowDescription"}
}
fieldCount := int(binary.BigEndian.Uint16(src))
rp := 2
dst.Fields = dst.Fields[0:0]
for i := 0; i < fieldCount; i++ {
var fd FieldDescription
idx := bytes.IndexByte(src[rp:], 0)
if idx < 0 {
return &invalidMessageFormatErr{messageType: "RowDescription"}
}
fd.Name = src[rp : rp+idx]
rp += idx + 1
// Since buf.Next() doesn't return an error if we hit the end of the buffer
// check Len ahead of time
if len(src[rp:]) < 18 {
return &invalidMessageFormatErr{messageType: "RowDescription"}
}
fd.TableOID = binary.BigEndian.Uint32(src[rp:])
rp += 4
fd.TableAttributeNumber = binary.BigEndian.Uint16(src[rp:])
rp += 2
fd.DataTypeOID = binary.BigEndian.Uint32(src[rp:])
rp += 4
fd.DataTypeSize = int16(binary.BigEndian.Uint16(src[rp:]))
rp += 2
fd.TypeModifier = int32(binary.BigEndian.Uint32(src[rp:]))
rp += 4
fd.Format = int16(binary.BigEndian.Uint16(src[rp:]))
rp += 2
dst.Fields = append(dst.Fields, fd)
}
return nil
}
// Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
func (src *RowDescription) Encode(dst []byte) ([]byte, error) {
dst, sp := beginMessage(dst, 'T')
if len(src.Fields) > math.MaxUint16 {
return nil, errors.New("too many fields")
}
dst = pgio.AppendUint16(dst, uint16(len(src.Fields)))
for _, fd := range src.Fields {
dst = append(dst, fd.Name...)
dst = append(dst, 0)
dst = pgio.AppendUint32(dst, fd.TableOID)
dst = pgio.AppendUint16(dst, fd.TableAttributeNumber)
dst = pgio.AppendUint32(dst, fd.DataTypeOID)
dst = pgio.AppendInt16(dst, fd.DataTypeSize)
dst = pgio.AppendInt32(dst, fd.TypeModifier)
dst = pgio.AppendInt16(dst, fd.Format)
}
return finishMessage(dst, sp)
}
// MarshalJSON implements encoding/json.Marshaler.
func (src RowDescription) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
Type string
Fields []FieldDescription
}{
Type: "RowDescription",
Fields: src.Fields,
})
}
// UnmarshalJSON implements encoding/json.Unmarshaler.
func (dst *RowDescription) UnmarshalJSON(data []byte) error {
var msg struct {
Fields []struct {
Name string
TableOID uint32
TableAttributeNumber uint16
DataTypeOID uint32
DataTypeSize int16
TypeModifier int32
Format int16
}
}
if err := json.Unmarshal(data, &msg); err != nil {
return err
}
dst.Fields = make([]FieldDescription, len(msg.Fields))
for n, field := range msg.Fields {
dst.Fields[n] = FieldDescription{
Name: []byte(field.Name),
TableOID: field.TableOID,
TableAttributeNumber: field.TableAttributeNumber,
DataTypeOID: field.DataTypeOID,
DataTypeSize: field.DataTypeSize,
TypeModifier: field.TypeModifier,
Format: field.Format,
}
}
return nil
}
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