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package pgproto3
import (
"encoding/binary"
"encoding/hex"
"encoding/json"
"errors"
"math"
"github.com/jackc/pgx/v5/internal/pgio"
)
type DataRow struct {
Values [][]byte
}
// Backend identifies this message as sendable by the PostgreSQL backend.
func (*DataRow) 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 *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"}
}
valueLen := int(int32(binary.BigEndian.Uint32(src[rp:])))
rp += 4
// null
if valueLen == -1 {
dst.Values[i] = nil
} else {
if len(src[rp:]) < valueLen || valueLen < 0 {
return &invalidMessageFormatErr{messageType: "DataRow"}
}
dst.Values[i] = src[rp : rp+valueLen : rp+valueLen]
rp += valueLen
}
}
return nil
}
// Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
func (src *DataRow) Encode(dst []byte) ([]byte, error) {
dst, sp := beginMessage(dst, 'D')
if len(src.Values) > math.MaxUint16 {
return nil, errors.New("too many values")
}
dst = pgio.AppendUint16(dst, uint16(len(src.Values)))
for _, v := range src.Values {
if v == nil {
dst = pgio.AppendInt32(dst, -1)
continue
}
dst = pgio.AppendInt32(dst, int32(len(v)))
dst = append(dst, v...)
}
return finishMessage(dst, sp)
}
// MarshalJSON implements encoding/json.Marshaler.
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,
})
}
// UnmarshalJSON implements encoding/json.Unmarshaler.
func (dst *DataRow) UnmarshalJSON(data []byte) error {
// Ignore null, like in the main JSON package.
if string(data) == "null" {
return nil
}
var msg struct {
Values []map[string]string
}
if err := json.Unmarshal(data, &msg); err != nil {
return err
}
dst.Values = make([][]byte, len(msg.Values))
for n, parameter := range msg.Values {
var err error
dst.Values[n], err = getValueFromJSON(parameter)
if err != nil {
return err
}
}
return nil
}
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