update serializing

message.go

@@ -0,0 +1,114 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"git.tornberg.me/go-cart-actor/git.tornberg.me/go-cart-actor/messages"
+	"google.golang.org/protobuf/proto"
+)
+
+type StorableMessage interface {
+	GetBytes() ([]byte, error)
+	FromReader(io.Reader, *Message) error
+}
+
+type Message struct {
+	Type      uint64
+	TimeStamp *int64
+	Content   interface{}
+}
+
+type MessageWriter struct {
+	writer io.Writer
+}
+
+func NewMessageWriter(b *bytes.Buffer) *MessageWriter {
+	return &MessageWriter{writer: bufio.NewWriter(b)}
+}
+
+func (w *MessageWriter) WriteUint64(value uint64) error {
+	bytes := make([]byte, 8)
+	binary.LittleEndian.PutUint64(bytes, value)
+	_, err := w.writer.Write(bytes)
+	return err
+}
+
+func (w *MessageWriter) WriteInt64(value int64) error {
+	return w.WriteUint64(uint64(value))
+}
+
+func (w *MessageWriter) WriteMessage(m *Message) error {
+	if err := w.WriteUint64(m.Type); err != nil {
+		return err
+	}
+	if err := w.WriteInt64(*m.TimeStamp); err != nil {
+		return err
+	}
+	var messageBytes []byte
+	var err error
+	if m.Type == AddRequestType {
+		messageBytes, err = proto.Marshal(m.Content.(*messages.AddRequest))
+	} else if m.Type == AddItemType {
+		messageBytes, err = proto.Marshal(m.Content.(*messages.AddItem))
+	} else {
+		return fmt.Errorf("unknown message type")
+	}
+	if err != nil {
+		return err
+	}
+	if err := w.WriteUint64(uint64(len(messageBytes))); err != nil {
+		return err
+	}
+	_, err = w.writer.Write(messageBytes)
+	return err
+}
+
+func (m Message) GetBytes() ([]byte, error) {
+	var b bytes.Buffer
+	mw := NewMessageWriter(&b)
+	err := mw.WriteMessage(&m)
+	return b.Bytes(), err
+}
+
+func (i Message) FromReader(reader io.Reader, m *Message) error {
+
+	bytes := make([]byte, 8)
+	if _, err := reader.Read(bytes); err != nil {
+		return err
+	}
+	m.Type = binary.LittleEndian.Uint64(bytes)
+	if _, err := reader.Read(bytes); err != nil {
+		return err
+	}
+	timestamp := int64(binary.LittleEndian.Uint64(bytes))
+	m.TimeStamp = &timestamp
+	if _, err := reader.Read(bytes); err != nil {
+		return err
+	}
+	messageBytes := make([]byte, binary.LittleEndian.Uint64(bytes))
+	if _, err := reader.Read(messageBytes); err != nil {
+		return err
+	}
+	var err error
+
+	if m.Type == AddRequestType {
+		msg := &messages.AddRequest{}
+		err = proto.Unmarshal(messageBytes, msg)
+		m.Content = msg
+	} else if m.Type == AddItemType {
+		msg := &messages.AddItem{}
+		err = proto.Unmarshal(messageBytes, msg)
+		m.Content = msg
+	} else {
+		return fmt.Errorf("unknown message type")
+	}
+	if err != nil {
+		return err
+	}
+
+	return nil
+}