87 lines
1.7 KiB
Go
87 lines
1.7 KiB
Go
package actor
|
|
|
|
import (
|
|
"encoding/json"
|
|
"errors"
|
|
"io"
|
|
"time"
|
|
|
|
"github.com/gogo/protobuf/proto"
|
|
)
|
|
|
|
type StateStorage struct {
|
|
registry MutationRegistry
|
|
}
|
|
|
|
type StorageEvent struct {
|
|
Type string `json:"type"`
|
|
TimeStamp time.Time `json:"timestamp"`
|
|
Mutation proto.Message `json:"mutation"`
|
|
}
|
|
|
|
type rawEvent struct {
|
|
Type string `json:"type"`
|
|
TimeStamp time.Time `json:"timestamp"`
|
|
Mutation json.RawMessage `json:"mutation"`
|
|
}
|
|
|
|
func NewState(registry MutationRegistry) *StateStorage {
|
|
return &StateStorage{
|
|
registry: registry,
|
|
}
|
|
}
|
|
|
|
var ErrUnknownType = errors.New("unknown type")
|
|
|
|
func (s *StateStorage) Load(r io.Reader, onMessage func(msg proto.Message)) error {
|
|
var err error
|
|
for err == nil {
|
|
evt, err := s.Read(r)
|
|
if err == nil {
|
|
onMessage(evt.Mutation)
|
|
}
|
|
|
|
}
|
|
return err
|
|
}
|
|
|
|
func (s *StateStorage) Append(io io.Writer, mutation proto.Message) error {
|
|
typeName, ok := s.registry.GetTypeName(mutation)
|
|
if !ok {
|
|
return ErrUnknownType
|
|
}
|
|
event := &StorageEvent{
|
|
Type: typeName,
|
|
TimeStamp: time.Now(),
|
|
Mutation: mutation,
|
|
}
|
|
jsonBytes, err := json.Marshal(event)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if _, err := io.Write(jsonBytes); err != nil {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (s *StateStorage) Read(r io.Reader) (*StorageEvent, error) {
|
|
var event rawEvent
|
|
if err := json.NewDecoder(r).Decode(&event); err != nil {
|
|
return nil, err
|
|
}
|
|
typeName := event.Type
|
|
mutation, ok := s.registry.Create(typeName)
|
|
if !ok {
|
|
return nil, ErrUnknownType
|
|
}
|
|
if err := json.Unmarshal(event.Mutation, mutation); err != nil {
|
|
return nil, err
|
|
}
|
|
return &StorageEvent{
|
|
Type: typeName,
|
|
TimeStamp: event.TimeStamp,
|
|
Mutation: mutation,
|
|
}, nil
|
|
}
|