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