Add dep

vendor/maunium.net/go/gomatrix/sync.go

@@ -0,0 +1,159 @@
+package gomatrix
+
+import (
+	"encoding/json"
+	"fmt"
+	"runtime/debug"
+	"time"
+)
+
+// Syncer represents an interface that must be satisfied in order to do /sync requests on a client.
+type Syncer interface {
+	// Process the /sync response. The since parameter is the since= value that was used to produce the response.
+	// This is useful for detecting the very first sync (since=""). If an error is return, Syncing will be stopped
+	// permanently.
+	ProcessResponse(resp *RespSync, since string) error
+	// OnFailedSync returns either the time to wait before retrying or an error to stop syncing permanently.
+	OnFailedSync(res *RespSync, err error) (time.Duration, error)
+	// GetFilterJSON for the given user ID. NOT the filter ID.
+	GetFilterJSON(userID string) json.RawMessage
+}
+
+// DefaultSyncer is the default syncing implementation. You can either write your own syncer, or selectively
+// replace parts of this default syncer (e.g. the ProcessResponse method). The default syncer uses the observer
+// pattern to notify callers about incoming events. See DefaultSyncer.OnEventType for more information.
+type DefaultSyncer struct {
+	UserID    string
+	Store     Storer
+	listeners map[EventType][]OnEventListener // event type to listeners array
+}
+
+// OnEventListener can be used with DefaultSyncer.OnEventType to be informed of incoming events.
+type OnEventListener func(*Event)
+
+// NewDefaultSyncer returns an instantiated DefaultSyncer
+func NewDefaultSyncer(userID string, store Storer) *DefaultSyncer {
+	return &DefaultSyncer{
+		UserID:    userID,
+		Store:     store,
+		listeners: make(map[EventType][]OnEventListener),
+	}
+}
+
+// ProcessResponse processes the /sync response in a way suitable for bots. "Suitable for bots" means a stream of
+// unrepeating events. Returns a fatal error if a listener panics.
+func (s *DefaultSyncer) ProcessResponse(res *RespSync, since string) (err error) {
+	if !s.shouldProcessResponse(res, since) {
+		return
+	}
+
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("ProcessResponse panicked! userID=%s since=%s panic=%s\n%s", s.UserID, since, r, debug.Stack())
+		}
+	}()
+
+	for roomID, roomData := range res.Rooms.Join {
+		room := s.getOrCreateRoom(roomID)
+		for _, event := range roomData.State.Events {
+			event.RoomID = roomID
+			room.UpdateState(event)
+			s.notifyListeners(event)
+		}
+		for _, event := range roomData.Timeline.Events {
+			event.RoomID = roomID
+			s.notifyListeners(event)
+		}
+	}
+	for roomID, roomData := range res.Rooms.Invite {
+		room := s.getOrCreateRoom(roomID)
+		for _, event := range roomData.State.Events {
+			event.RoomID = roomID
+			room.UpdateState(event)
+			s.notifyListeners(event)
+		}
+	}
+	for roomID, roomData := range res.Rooms.Leave {
+		room := s.getOrCreateRoom(roomID)
+		for _, event := range roomData.Timeline.Events {
+			if event.StateKey != nil {
+				event.RoomID = roomID
+				room.UpdateState(event)
+				s.notifyListeners(event)
+			}
+		}
+	}
+	return
+}
+
+// OnEventType allows callers to be notified when there are new events for the given event type.
+// There are no duplicate checks.
+func (s *DefaultSyncer) OnEventType(eventType EventType, callback OnEventListener) {
+	_, exists := s.listeners[eventType]
+	if !exists {
+		s.listeners[eventType] = []OnEventListener{}
+	}
+	s.listeners[eventType] = append(s.listeners[eventType], callback)
+}
+
+// shouldProcessResponse returns true if the response should be processed. May modify the response to remove
+// stuff that shouldn't be processed.
+func (s *DefaultSyncer) shouldProcessResponse(resp *RespSync, since string) bool {
+	if since == "" {
+		return false
+	}
+	// This is a horrible hack because /sync will return the most recent messages for a room
+	// as soon as you /join it. We do NOT want to process those events in that particular room
+	// because they may have already been processed (if you toggle the bot in/out of the room).
+	//
+	// Work around this by inspecting each room's timeline and seeing if an m.room.member event for us
+	// exists and is "join" and then discard processing that room entirely if so.
+	// TODO: We probably want to process messages from after the last join event in the timeline.
+	for roomID, roomData := range resp.Rooms.Join {
+		for i := len(roomData.Timeline.Events) - 1; i >= 0; i-- {
+			e := roomData.Timeline.Events[i]
+			if e.Type == StateMember && e.GetStateKey() == s.UserID {
+				if e.Content.Membership == "join" {
+					_, ok := resp.Rooms.Join[roomID]
+					if !ok {
+						continue
+					}
+					delete(resp.Rooms.Join, roomID)   // don't re-process messages
+					delete(resp.Rooms.Invite, roomID) // don't re-process invites
+					break
+				}
+			}
+		}
+	}
+	return true
+}
+
+// getOrCreateRoom must only be called by the Sync() goroutine which calls ProcessResponse()
+func (s *DefaultSyncer) getOrCreateRoom(roomID string) *Room {
+	room := s.Store.LoadRoom(roomID)
+	if room == nil { // create a new Room
+		room = NewRoom(roomID)
+		s.Store.SaveRoom(room)
+	}
+	return room
+}
+
+func (s *DefaultSyncer) notifyListeners(event *Event) {
+	listeners, exists := s.listeners[event.Type]
+	if !exists {
+		return
+	}
+	for _, fn := range listeners {
+		fn(event)
+	}
+}
+
+// OnFailedSync always returns a 10 second wait period between failed /syncs, never a fatal error.
+func (s *DefaultSyncer) OnFailedSync(res *RespSync, err error) (time.Duration, error) {
+	return 10 * time.Second, nil
+}
+
+// GetFilterJSON returns a filter with a timeline limit of 50.
+func (s *DefaultSyncer) GetFilterJSON(userID string) json.RawMessage {
+	return json.RawMessage(`{"room":{"timeline":{"limit":50}}}`)
+}