Add pgproto3.Backend

execute.go

@@ -0,0 +1,60 @@
+package pgproto3
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/json"
+)
+
+type Execute struct {
+	Portal  string
+	MaxRows uint32
+}
+
+func (*Execute) Frontend() {}
+
+func (dst *Execute) Decode(src []byte) error {
+	buf := bytes.NewBuffer(src)
+
+	b, err := buf.ReadBytes(0)
+	if err != nil {
+		return err
+	}
+	dst.Portal = string(b[:len(b)-1])
+
+	if buf.Len() < 4 {
+		return &invalidMessageFormatErr{messageType: "Execute"}
+	}
+	dst.MaxRows = binary.BigEndian.Uint32(buf.Next(4))
+
+	return nil
+}
+
+func (src *Execute) MarshalBinary() ([]byte, error) {
+	var bigEndian BigEndianBuf
+	buf := &bytes.Buffer{}
+
+	buf.WriteByte('E')
+	buf.Write(bigEndian.Uint32(0))
+
+	buf.WriteString(src.Portal)
+	buf.WriteByte(0)
+
+	buf.Write(bigEndian.Uint32(src.MaxRows))
+
+	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+
+	return buf.Bytes(), nil
+}
+
+func (src *Execute) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Type    string
+		Portal  string
+		MaxRows uint32
+	}{
+		Type:    "Execute",
+		Portal:  src.Portal,
+		MaxRows: src.MaxRows,
+	})
+}