pgx/pgproto3/data_row.go

115 lines
2.2 KiB
Go

package pgproto3
import (
"bytes"
"encoding/binary"
"encoding/hex"
"encoding/json"
)
type DataRow struct {
Values [][]byte
}
func (*DataRow) Backend() {}
func (dst *DataRow) Decode(src []byte) error {
if len(src) < 2 {
return &invalidMessageFormatErr{messageType: "DataRow"}
}
rp := 0
fieldCount := int(binary.BigEndian.Uint16(src[rp:]))
rp += 2
// If the capacity of the values slice is too small OR substantially too
// large reallocate. This is too avoid one row with many columns from
// permanently allocating memory.
if cap(dst.Values) < fieldCount || cap(dst.Values)-fieldCount > 32 {
newCap := 32
if newCap < fieldCount {
newCap = fieldCount
}
dst.Values = make([][]byte, fieldCount, newCap)
} else {
dst.Values = dst.Values[:fieldCount]
}
for i := 0; i < fieldCount; i++ {
if len(src[rp:]) < 4 {
return &invalidMessageFormatErr{messageType: "DataRow"}
}
msgSize := int(int32(binary.BigEndian.Uint32(src[rp:])))
rp += 4
// null
if msgSize == -1 {
dst.Values[i] = nil
} else {
if len(src[rp:]) < msgSize {
return &invalidMessageFormatErr{messageType: "DataRow"}
}
dst.Values[i] = src[rp : rp+msgSize]
rp += msgSize
}
}
return nil
}
func (src *DataRow) MarshalBinary() ([]byte, error) {
var bigEndian BigEndianBuf
buf := &bytes.Buffer{}
buf.WriteByte('D')
buf.Write(bigEndian.Uint32(0))
buf.Write(bigEndian.Uint16(uint16(len(src.Values))))
for _, v := range src.Values {
if v == nil {
buf.Write(bigEndian.Int32(-1))
continue
}
buf.Write(bigEndian.Int32(int32(len(v))))
buf.Write(v)
}
binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
return buf.Bytes(), nil
}
func (src *DataRow) MarshalJSON() ([]byte, error) {
formattedValues := make([]map[string]string, len(src.Values))
for i, v := range src.Values {
if v == nil {
continue
}
var hasNonPrintable bool
for _, b := range v {
if b < 32 {
hasNonPrintable = true
break
}
}
if hasNonPrintable {
formattedValues[i] = map[string]string{"binary": hex.EncodeToString(v)}
} else {
formattedValues[i] = map[string]string{"text": string(v)}
}
}
return json.Marshal(struct {
Type string
Values []map[string]string
}{
Type: "DataRow",
Values: formattedValues,
})
}