Merge remote-tracking branch 'pgproto3/master' into v5-dev

Pull in pgproto3 changes and update for pgx v5

pgproto3/authentication_gss_continue.go

@@ -0,0 +1,68 @@
+package pgproto3
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"errors"
+
+	"github.com/jackc/pgx/v5/internal/pgio"
+)
+
+type AuthenticationGSSContinue struct {
+	Data []byte
+}
+
+func (a *AuthenticationGSSContinue) Backend() {}
+
+func (a *AuthenticationGSSContinue) AuthenticationResponse() {}
+
+func (a *AuthenticationGSSContinue) Decode(src []byte) error {
+	if len(src) < 4 {
+		return errors.New("authentication message too short")
+	}
+
+	authType := binary.BigEndian.Uint32(src)
+
+	if authType != AuthTypeGSSCont {
+		return errors.New("bad auth type")
+	}
+
+	a.Data = src[4:]
+	return nil
+}
+
+func (a *AuthenticationGSSContinue) Encode(dst []byte) []byte {
+	dst = append(dst, 'R')
+	dst = pgio.AppendInt32(dst, int32(len(a.Data))+8)
+	dst = pgio.AppendUint32(dst, AuthTypeGSSCont)
+	dst = append(dst, a.Data...)
+	return dst
+}
+
+func (a *AuthenticationGSSContinue) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Type string
+		Data []byte
+	}{
+		Type: "AuthenticationGSSContinue",
+		Data: a.Data,
+	})
+}
+
+func (a *AuthenticationGSSContinue) UnmarshalJSON(data []byte) error {
+	// Ignore null, like in the main JSON package.
+	if string(data) == "null" {
+		return nil
+	}
+
+	var msg struct {
+		Type string
+		Data []byte
+	}
+	if err := json.Unmarshal(data, &msg); err != nil {
+		return err
+	}
+
+	a.Data = msg.Data
+	return nil
+}