Initial commit

vendor/github.com/jackc/pgproto3/v2/row_description.go

@@ -0,0 +1,165 @@
+package pgproto3
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/json"
+
+	"github.com/jackc/pgio"
+)
+
+const (
+	TextFormat   = 0
+	BinaryFormat = 1
+)
+
+type FieldDescription struct {
+	Name                 []byte
+	TableOID             uint32
+	TableAttributeNumber uint16
+	DataTypeOID          uint32
+	DataTypeSize         int16
+	TypeModifier         int32
+	Format               int16
+}
+
+// MarshalJSON implements encoding/json.Marshaler.
+func (fd FieldDescription) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Name                 string
+		TableOID             uint32
+		TableAttributeNumber uint16
+		DataTypeOID          uint32
+		DataTypeSize         int16
+		TypeModifier         int32
+		Format               int16
+	}{
+		Name:                 string(fd.Name),
+		TableOID:             fd.TableOID,
+		TableAttributeNumber: fd.TableAttributeNumber,
+		DataTypeOID:          fd.DataTypeOID,
+		DataTypeSize:         fd.DataTypeSize,
+		TypeModifier:         fd.TypeModifier,
+		Format:               fd.Format,
+	})
+}
+
+type RowDescription struct {
+	Fields []FieldDescription
+}
+
+// Backend identifies this message as sendable by the PostgreSQL backend.
+func (*RowDescription) 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 *RowDescription) Decode(src []byte) error {
+
+	if len(src) < 2 {
+		return &invalidMessageFormatErr{messageType: "RowDescription"}
+	}
+	fieldCount := int(binary.BigEndian.Uint16(src))
+	rp := 2
+
+	dst.Fields = dst.Fields[0:0]
+
+	for i := 0; i < fieldCount; i++ {
+		var fd FieldDescription
+
+		idx := bytes.IndexByte(src[rp:], 0)
+		if idx < 0 {
+			return &invalidMessageFormatErr{messageType: "RowDescription"}
+		}
+		fd.Name = src[rp : rp+idx]
+		rp += idx + 1
+
+		// Since buf.Next() doesn't return an error if we hit the end of the buffer
+		// check Len ahead of time
+		if len(src[rp:]) < 18 {
+			return &invalidMessageFormatErr{messageType: "RowDescription"}
+		}
+
+		fd.TableOID = binary.BigEndian.Uint32(src[rp:])
+		rp += 4
+		fd.TableAttributeNumber = binary.BigEndian.Uint16(src[rp:])
+		rp += 2
+		fd.DataTypeOID = binary.BigEndian.Uint32(src[rp:])
+		rp += 4
+		fd.DataTypeSize = int16(binary.BigEndian.Uint16(src[rp:]))
+		rp += 2
+		fd.TypeModifier = int32(binary.BigEndian.Uint32(src[rp:]))
+		rp += 4
+		fd.Format = int16(binary.BigEndian.Uint16(src[rp:]))
+		rp += 2
+
+		dst.Fields = append(dst.Fields, fd)
+	}
+
+	return nil
+}
+
+// Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
+func (src *RowDescription) Encode(dst []byte) []byte {
+	dst = append(dst, 'T')
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
+
+	dst = pgio.AppendUint16(dst, uint16(len(src.Fields)))
+	for _, fd := range src.Fields {
+		dst = append(dst, fd.Name...)
+		dst = append(dst, 0)
+
+		dst = pgio.AppendUint32(dst, fd.TableOID)
+		dst = pgio.AppendUint16(dst, fd.TableAttributeNumber)
+		dst = pgio.AppendUint32(dst, fd.DataTypeOID)
+		dst = pgio.AppendInt16(dst, fd.DataTypeSize)
+		dst = pgio.AppendInt32(dst, fd.TypeModifier)
+		dst = pgio.AppendInt16(dst, fd.Format)
+	}
+
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
+
+	return dst
+}
+
+// MarshalJSON implements encoding/json.Marshaler.
+func (src RowDescription) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Type   string
+		Fields []FieldDescription
+	}{
+		Type:   "RowDescription",
+		Fields: src.Fields,
+	})
+}
+
+// UnmarshalJSON implements encoding/json.Unmarshaler.
+func (dst *RowDescription) UnmarshalJSON(data []byte) error {
+	var msg struct {
+		Fields []struct {
+			Name                 string
+			TableOID             uint32
+			TableAttributeNumber uint16
+			DataTypeOID          uint32
+			DataTypeSize         int16
+			TypeModifier         int32
+			Format               int16
+		}
+	}
+	if err := json.Unmarshal(data, &msg); err != nil {
+		return err
+	}
+	dst.Fields = make([]FieldDescription, len(msg.Fields))
+	for n, field := range msg.Fields {
+		dst.Fields[n] = FieldDescription{
+			Name:                 []byte(field.Name),
+			TableOID:             field.TableOID,
+			TableAttributeNumber: field.TableAttributeNumber,
+			DataTypeOID:          field.DataTypeOID,
+			DataTypeSize:         field.DataTypeSize,
+			TypeModifier:         field.TypeModifier,
+			Format:               field.Format,
+		}
+	}
+	return nil
+}