112 lines
2.0 KiB
Go
112 lines
2.0 KiB
Go
package main
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"io"
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"time"
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messages "git.tornberg.me/go-cart-actor/proto"
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"google.golang.org/protobuf/proto"
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)
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type StorableMessage interface {
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Write(w io.Writer) error
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}
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type Message struct {
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Type uint16
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TimeStamp *int64
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Content interface{}
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}
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type MessageWriter struct {
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io.Writer
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}
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type StorableMessageHeader struct {
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Version uint16
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Type uint16
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TimeStamp int64
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DataLength uint64
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}
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func GetData(fn func(w io.Writer) error) ([]byte, error) {
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var buf bytes.Buffer
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err := fn(&buf)
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if err != nil {
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return nil, err
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}
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b := buf.Bytes()
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return b, nil
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}
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func (m Message) Write(w io.Writer) error {
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data, err := GetData(func(wr io.Writer) error {
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if m.Type == AddRequestType {
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messageBytes, err := proto.Marshal(m.Content.(*messages.AddRequest))
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if err != nil {
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return err
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}
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wr.Write(messageBytes)
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} else if m.Type == AddItemType {
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messageBytes, err := proto.Marshal(m.Content.(*messages.AddItem))
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if err != nil {
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return err
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}
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wr.Write(messageBytes)
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}
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return nil
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})
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if err != nil {
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return err
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}
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ts := time.Now().Unix()
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if m.TimeStamp != nil {
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ts = *m.TimeStamp
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}
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err = binary.Write(w, binary.LittleEndian, StorableMessageHeader{
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Version: 1,
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Type: m.Type,
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TimeStamp: ts,
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DataLength: uint64(len(data)),
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})
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w.Write(data)
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return err
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}
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func ReadMessage(reader io.Reader, m *Message) error {
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header := StorableMessageHeader{}
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err := binary.Read(reader, binary.LittleEndian, &header)
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if err != nil {
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return err
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}
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messageBytes := make([]byte, header.DataLength)
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_, err = reader.Read(messageBytes)
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if err != nil {
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return err
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}
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switch header.Type {
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case AddRequestType:
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msg := &messages.AddRequest{}
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err = proto.Unmarshal(messageBytes, msg)
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m.Content = msg
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case AddItemType:
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msg := &messages.AddItem{}
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err = proto.Unmarshal(messageBytes, msg)
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m.Content = msg
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default:
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return fmt.Errorf("unknown message type")
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}
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if err != nil {
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return err
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}
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m.Type = header.Type
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m.TimeStamp = &header.TimeStamp
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return nil
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}
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