Introduce pgproto3 package

pgproto3 will wrap the message encoding and decoding for the PostgreSQL
frontend/backend protocol version 3.

error_response.go

@@ -0,0 +1,197 @@
+package pgproto3
+
+import (
+	"bytes"
+	"encoding/binary"
+	"strconv"
+)
+
+type ErrorResponse struct {
+	Severity         string
+	Code             string
+	Message          string
+	Detail           string
+	Hint             string
+	Position         int32
+	InternalPosition int32
+	InternalQuery    string
+	Where            string
+	SchemaName       string
+	TableName        string
+	ColumnName       string
+	DataTypeName     string
+	ConstraintName   string
+	File             string
+	Line             int32
+	Routine          string
+
+	UnknownFields map[byte]string
+}
+
+func (*ErrorResponse) Backend() {}
+
+func (dst *ErrorResponse) UnmarshalBinary(src []byte) error {
+	*dst = ErrorResponse{}
+
+	buf := bytes.NewBuffer(src)
+
+	for {
+		k, err := buf.ReadByte()
+		if err != nil {
+			return err
+		}
+		if k == 0 {
+			break
+		}
+
+		vb, err := buf.ReadBytes(0)
+		if err != nil {
+			return err
+		}
+		v := string(vb[:len(vb)-1])
+
+		switch k {
+		case 'S':
+			dst.Severity = v
+		case 'C':
+			dst.Code = v
+		case 'M':
+			dst.Message = v
+		case 'D':
+			dst.Detail = v
+		case 'H':
+			dst.Hint = v
+		case 'P':
+			s := v
+			n, _ := strconv.ParseInt(s, 10, 32)
+			dst.Position = int32(n)
+		case 'p':
+			s := v
+			n, _ := strconv.ParseInt(s, 10, 32)
+			dst.InternalPosition = int32(n)
+		case 'q':
+			dst.InternalQuery = v
+		case 'W':
+			dst.Where = v
+		case 's':
+			dst.SchemaName = v
+		case 't':
+			dst.TableName = v
+		case 'c':
+			dst.ColumnName = v
+		case 'd':
+			dst.DataTypeName = v
+		case 'n':
+			dst.ConstraintName = v
+		case 'F':
+			dst.File = v
+		case 'L':
+			s := v
+			n, _ := strconv.ParseInt(s, 10, 32)
+			dst.Line = int32(n)
+		case 'R':
+			dst.Routine = v
+
+		default:
+			if dst.UnknownFields == nil {
+				dst.UnknownFields = make(map[byte]string)
+			}
+			dst.UnknownFields[k] = v
+		}
+	}
+
+	return nil
+}
+
+func (src *ErrorResponse) MarshalBinary() ([]byte, error) {
+	return src.marshalBinary('E')
+}
+
+func (src *ErrorResponse) marshalBinary(typeByte byte) ([]byte, error) {
+	var bigEndian BigEndianBuf
+	buf := &bytes.Buffer{}
+
+	buf.WriteByte(typeByte)
+	buf.Write(bigEndian.Uint32(0))
+
+	if src.Severity != "" {
+		buf.WriteString(src.Severity)
+		buf.WriteByte(0)
+	}
+	if src.Code != "" {
+		buf.WriteString(src.Code)
+		buf.WriteByte(0)
+	}
+	if src.Message != "" {
+		buf.WriteString(src.Message)
+		buf.WriteByte(0)
+	}
+	if src.Detail != "" {
+		buf.WriteString(src.Detail)
+		buf.WriteByte(0)
+	}
+	if src.Hint != "" {
+		buf.WriteString(src.Hint)
+		buf.WriteByte(0)
+	}
+	if src.Position != 0 {
+		buf.WriteString(strconv.Itoa(int(src.Position)))
+		buf.WriteByte(0)
+	}
+	if src.InternalPosition != 0 {
+		buf.WriteString(strconv.Itoa(int(src.InternalPosition)))
+		buf.WriteByte(0)
+	}
+	if src.InternalQuery != "" {
+		buf.WriteString(src.InternalQuery)
+		buf.WriteByte(0)
+	}
+	if src.Where != "" {
+		buf.WriteString(src.Where)
+		buf.WriteByte(0)
+	}
+	if src.SchemaName != "" {
+		buf.WriteString(src.SchemaName)
+		buf.WriteByte(0)
+	}
+	if src.TableName != "" {
+		buf.WriteString(src.TableName)
+		buf.WriteByte(0)
+	}
+	if src.ColumnName != "" {
+		buf.WriteString(src.ColumnName)
+		buf.WriteByte(0)
+	}
+	if src.DataTypeName != "" {
+		buf.WriteString(src.DataTypeName)
+		buf.WriteByte(0)
+	}
+	if src.ConstraintName != "" {
+		buf.WriteString(src.ConstraintName)
+		buf.WriteByte(0)
+	}
+	if src.File != "" {
+		buf.WriteString(src.File)
+		buf.WriteByte(0)
+	}
+	if src.Line != 0 {
+		buf.WriteString(strconv.Itoa(int(src.Line)))
+		buf.WriteByte(0)
+	}
+	if src.Routine != "" {
+		buf.WriteString(src.Routine)
+		buf.WriteByte(0)
+	}
+
+	for k, v := range src.UnknownFields {
+		buf.WriteByte(k)
+		buf.WriteByte(0)
+		buf.WriteString(v)
+		buf.WriteByte(0)
+	}
+	buf.WriteByte(0)
+
+	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+
+	return buf.Bytes(), nil
+}