open-vault/vendor/github.com/jackc/pgx/pgproto3/row_description.go

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2018-10-03 16:55:26 +00:00
package pgproto3
import (
"bytes"
"encoding/binary"
"encoding/json"
"github.com/jackc/pgx/pgio"
)
const (
TextFormat = 0
BinaryFormat = 1
)
type FieldDescription struct {
Name string
TableOID uint32
TableAttributeNumber uint16
DataTypeOID uint32
DataTypeSize int16
TypeModifier int32
Format int16
}
type RowDescription struct {
Fields []FieldDescription
}
func (*RowDescription) Backend() {}
func (dst *RowDescription) Decode(src []byte) error {
buf := bytes.NewBuffer(src)
if buf.Len() < 2 {
return &invalidMessageFormatErr{messageType: "RowDescription"}
}
fieldCount := int(binary.BigEndian.Uint16(buf.Next(2)))
*dst = RowDescription{Fields: make([]FieldDescription, fieldCount)}
for i := 0; i < fieldCount; i++ {
var fd FieldDescription
bName, err := buf.ReadBytes(0)
if err != nil {
return err
}
fd.Name = string(bName[:len(bName)-1])
// Since buf.Next() doesn't return an error if we hit the end of the buffer
// check Len ahead of time
if buf.Len() < 18 {
return &invalidMessageFormatErr{messageType: "RowDescription"}
}
fd.TableOID = binary.BigEndian.Uint32(buf.Next(4))
fd.TableAttributeNumber = binary.BigEndian.Uint16(buf.Next(2))
fd.DataTypeOID = binary.BigEndian.Uint32(buf.Next(4))
fd.DataTypeSize = int16(binary.BigEndian.Uint16(buf.Next(2)))
fd.TypeModifier = int32(binary.BigEndian.Uint32(buf.Next(4)))
fd.Format = int16(binary.BigEndian.Uint16(buf.Next(2)))
dst.Fields[i] = fd
}
return nil
}
func (src *RowDescription) Encode(dst []byte) []byte {
dst = append(dst, 'T')
sp := len(dst)
dst = pgio.AppendInt32(dst, -1)
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)
}
pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
return dst
}
func (src *RowDescription) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
Type string
Fields []FieldDescription
}{
Type: "RowDescription",
Fields: src.Fields,
})
}