Add flush and close messages to pgproto3

pgproto3/backend.go

@@ -14,8 +14,10 @@ type Backend struct {
 
 	// Frontend message flyweights
 	bind            Bind
+	_close          Close
 	describe        Describe
 	execute         Execute
+	flush           Flush
 	parse           Parse
 	passwordMessage PasswordMessage
 	query           Query
@@ -72,10 +74,14 @@ func (b *Backend) Receive() (FrontendMessage, error) {
 	switch msgType {
 	case 'B':
 		msg = &b.bind
+	case 'C':
+		msg = &b._close
 	case 'D':
 		msg = &b.describe
 	case 'E':
 		msg = &b.execute
+	case 'H':
+		msg = &b.flush
 	case 'P':
 		msg = &b.parse
 	case 'p':

pgproto3/close.go

@@ -0,0 +1,60 @@
+package pgproto3
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/json"
+)
+
+type Close struct {
+	ObjectType byte // 'S' = prepared statement, 'P' = portal
+	Name       string
+}
+
+func (*Close) Frontend() {}
+
+func (dst *Close) Decode(src []byte) error {
+	if len(src) < 2 {
+		return &invalidMessageFormatErr{messageType: "Close"}
+	}
+
+	dst.ObjectType = src[0]
+	rp := 1
+
+	idx := bytes.IndexByte(src[rp:], 0)
+	if idx != len(src[rp:])-1 {
+		return &invalidMessageFormatErr{messageType: "Close"}
+	}
+
+	dst.Name = string(src[rp : len(src)-1])
+
+	return nil
+}
+
+func (src *Close) MarshalBinary() ([]byte, error) {
+	var bigEndian BigEndianBuf
+	buf := &bytes.Buffer{}
+
+	buf.WriteByte('C')
+	buf.Write(bigEndian.Uint32(0))
+
+	buf.WriteByte(src.ObjectType)
+	buf.WriteString(src.Name)
+	buf.WriteByte(0)
+
+	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+
+	return buf.Bytes(), nil
+}
+
+func (src *Close) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Type       string
+		ObjectType string
+		Name       string
+	}{
+		Type:       "Close",
+		ObjectType: string(src.ObjectType),
+		Name:       src.Name,
+	})
+}

pgproto3/flush.go

@@ -0,0 +1,29 @@
+package pgproto3
+
+import (
+	"encoding/json"
+)
+
+type Flush struct{}
+
+func (*Flush) Frontend() {}
+
+func (dst *Flush) Decode(src []byte) error {
+	if len(src) != 0 {
+		return &invalidMessageLenErr{messageType: "Flush", expectedLen: 0, actualLen: len(src)}
+	}
+
+	return nil
+}
+
+func (src *Flush) MarshalBinary() ([]byte, error) {
+	return []byte{'H', 0, 0, 0, 4}, nil
+}
+
+func (src *Flush) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Type string
+	}{
+		Type: "Flush",
+	})
+}