Organize participant map

lib/src/core/participant_collection.dart

@@ -0,0 +1,51 @@
+// Copyright 2024 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'dart:collection';
+
+import '../participant/participant.dart';
+
+/// Small helper to keep participant lookups by identity and sid in sync.
+class ParticipantCollection<T extends Participant> extends IterableBase<T> {
+  final Map<String, T> _byIdentity = {};
+  final Map<String, T> _bySid = {};
+
+  // Read-only views of the collections
+  UnmodifiableMapView<String, T> get byIdentity => UnmodifiableMapView(_byIdentity);
+  UnmodifiableMapView<String, T> get bySid => UnmodifiableMapView(_bySid);
+
+  // Update methods
+  void set(T participant) {
+    _byIdentity[participant.identity] = participant;
+    _bySid[participant.sid] = participant;
+  }
+
+  // Contains methods
+  bool containsIdentity(String identity) => _byIdentity.containsKey(identity);
+  bool containsSid(String sid) => _bySid.containsKey(sid);
+
+  void clear() {
+    _byIdentity.clear();
+    _bySid.clear();
+  }
+
+  T? removeByIdentity(String identity) {
+    final participant = _byIdentity.remove(identity);
+    if (participant == null) return null;
+    return _bySid.remove(participant.sid);
+  }
+
+  @override
+  Iterator<T> get iterator => _byIdentity.values.iterator;
+}

lib/src/core/room.dart

@@ -54,6 +54,7 @@ import '../types/rpc.dart';
 import '../types/transcription_segment.dart';
 import '../utils.dart' show unpackStreamId;
 import 'engine.dart';
+import 'participant_collection.dart';
 import 'pending_track_queue.dart';
 
 /// Room is the primary construct for LiveKit conferences. It contains a
@@ -72,10 +73,9 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
   ConnectOptions get connectOptions => engine.connectOptions;
   RoomOptions get roomOptions => engine.roomOptions;
 
-  /// map of identity: [[RemoteParticipant]]
-  UnmodifiableMapView<String, RemoteParticipant> get remoteParticipants => UnmodifiableMapView(_remoteParticipants);
-  final _remoteParticipants = <String, RemoteParticipant>{};
-  final Map<String, String> _sidToIdentity = <String, String>{};
+  final ParticipantCollection<RemoteParticipant> _remoteParticipants = ParticipantCollection();
+  UnmodifiableMapView<String, RemoteParticipant> get remoteParticipants =>
+      UnmodifiableMapView(_remoteParticipants.byIdentity);
 
   /// the current participant
   LocalParticipant? get localParticipant => _localParticipant;
@@ -373,7 +373,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
           'allowed:${event.allowed}');
 
       // find participant
-      final participant = _getRemoteParticipantBySid(event.participantSid);
+      final participant = _remoteParticipants.bySid[event.participantSid];
       if (participant == null) {
         return;
       }
@@ -519,30 +519,28 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
     ..on<EngineFullRestartingEvent>((event) async {
       events.emit(const RoomReconnectingEvent());
 
-      // clean up RemoteParticipants
-      final copy = _remoteParticipants.values.toList();
-
-      _remoteParticipants.clear();
-      _sidToIdentity.clear();
-      _activeSpeakers.clear();
       // reset params
       _name = null;
       _metadata = null;
       _serverVersion = null;
       _serverRegion = null;
 
-      for (final participant in copy) {
+      final participants = _remoteParticipants.toList();
+      _remoteParticipants.clear();
+      _activeSpeakers.clear();
+      for (final participant in participants) {
         events.emit(ParticipantDisconnectedEvent(participant: participant));
         await participant.removeAllPublishedTracks(notify: false);
         await participant.dispose();
       }
+
       notifyListeners();
     })
     ..on<EngineRestartedEvent>((event) async {
       // re-publish all tracks
       await localParticipant?.rePublishAllTracks();
 
-      for (var participant in remoteParticipants.values) {
+      for (var participant in _remoteParticipants) {
         for (var pub in participant.trackPublications.values) {
           if (pub.subscribed) {
             pub.sendUpdateTrackSettings();
@@ -601,7 +599,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
         trackSid = streamId;
       }
 
-      final participant = _getRemoteParticipantBySid(participantSid);
+      final participant = _remoteParticipants.bySid[participantSid];
       try {
         if (trackSid == null || trackSid.isEmpty) {
           throw TrackSubscriptionExceptionEvent(
@@ -665,23 +663,15 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
     if (_localParticipant?.identity == identity) {
       return _localParticipant;
     }
-    return remoteParticipants[identity];
-  }
-
-  RemoteParticipant? _getRemoteParticipantBySid(String sid) {
-    final identity = _sidToIdentity[sid];
-    if (identity != null) {
-      return remoteParticipants[identity];
-    }
-    return null;
+    return _remoteParticipants.byIdentity[identity];
   }
 
   Future<ParticipantCreationResult> _getOrCreateRemoteParticipant(lk_models.ParticipantInfo info) async {
     if (!info.hasIdentity() || !info.hasSid()) {
       throw Exception('ParticipantInfo must have identity and sid');
     }
 
-    final participant = _remoteParticipants[info.identity];
+    final participant = _remoteParticipants.byIdentity[info.identity];
     if (participant != null) {
       // Return existing participant with no new publications; caller handles updates.
       return ParticipantCreationResult(
@@ -695,8 +685,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
       info: info,
     );
 
-    _remoteParticipants[result.participant.identity] = result.participant;
-    _sidToIdentity[result.participant.sid] = result.participant.identity;
+    _remoteParticipants.set(result.participant);
     await _flushPendingTracks(participant: result.participant);
     return result;
   }
@@ -718,7 +707,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
         continue;
       }
 
-      final isNew = !_remoteParticipants.containsKey(info.identity);
+      final isNew = !_remoteParticipants.containsIdentity(info.identity);
 
       if (info.state == lk_models.ParticipantInfo_State.DISCONNECTED) {
         hasChanged = await _handleParticipantDisconnect(info.identity);
@@ -741,12 +730,12 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
             [result.participant.events, events].emit(event);
           }
         }
-        _sidToIdentity[info.sid] = info.identity;
+        _remoteParticipants.set(result.participant);
         await _flushPendingTracks(participant: result.participant);
       } else {
         final wasUpdated = await result.participant.updateFromInfo(info);
         if (wasUpdated) {
-          _sidToIdentity[info.sid] = info.identity;
+          _remoteParticipants.set(result.participant);
           await _flushPendingTracks(participant: result.participant);
         }
       }
@@ -763,7 +752,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
     };
 
     for (final speaker in speakers) {
-      Participant? p = _getRemoteParticipantBySid(speaker.sid);
+      Participant? p = _remoteParticipants.bySid[speaker.sid];
       if (speaker.sid == localParticipant?.sid) p = localParticipant;
       if (p == null) continue;
 
@@ -786,7 +775,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
         isConnected: connectionState == ConnectionState.connected,
         participantSid: participant?.sid,
         subscriber: (pending) async {
-          final target = participant ?? _getRemoteParticipantBySid(pending.participantSid);
+          final target = participant ?? _remoteParticipants.bySid[pending.participantSid];
           if (target == null) return false;
           try {
             await target.addSubscribedMediaTrack(
@@ -816,7 +805,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
     // localParticipant & remote participants
     final allParticipants = <String, Participant>{
       if (localParticipant != null) localParticipant!.sid: localParticipant!,
-      ..._remoteParticipants,
+      ..._remoteParticipants.bySid,
     };
 
     for (final speaker in speakers) {
@@ -847,7 +836,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
       if (entry.participantSid == localParticipant?.sid) {
         participant = localParticipant;
       } else {
-        participant = _getRemoteParticipantBySid(entry.participantSid);
+        participant = _remoteParticipants.bySid[entry.participantSid];
       }
 
       if (participant != null) {
@@ -859,14 +848,12 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
 
   void _onSignalStreamStateUpdateEvent(List<lk_rtc.StreamStateInfo> updates) async {
     for (final update in updates) {
-      final identity = _sidToIdentity[update.participantSid];
-      if (identity == null) {
-        logger.warning('participant not found for sid ${update.participantSid}');
+      // try to find RemoteParticipant
+      final participant = _remoteParticipants.bySid[update.participantSid];
+      if (participant == null) {
+        logger.warning('Participant not found for sid ${update.participantSid}');
         continue;
       }
-      // try to find RemoteParticipant
-      final participant = remoteParticipants[identity];
-      if (participant == null) continue;
       // try to find RemoteTrackPublication
       final trackPublication = participant.trackPublications[update.trackSid];
       if (trackPublication == null) continue;
@@ -933,10 +920,8 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
   }
 
   Future<bool> _handleParticipantDisconnect(String identity) async {
-    final participant = _remoteParticipants.remove(identity);
-    if (participant == null) {
-      return false;
-    }
+    final participant = _remoteParticipants.removeByIdentity(identity);
+    if (participant == null) return false;
 
     validateParticipantHasNoActiveDataStreams(identity);
 
@@ -952,7 +937,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
     final trackSids = <String>[];
     final trackSidsDisabled = <String>[];
 
-    for (var participant in remoteParticipants.values) {
+    for (var participant in _remoteParticipants) {
       for (var track in participant.trackPublications.values) {
         if (track.subscribed != autoSubscribe) {
           trackSids.add(track.sid);
@@ -981,14 +966,13 @@ extension RoomPrivateMethods on Room {
     logger.fine('[${objectId}] cleanUp()');
 
     // clean up RemoteParticipants
-    final participants = _remoteParticipants.values.toList();
+    final participants = _remoteParticipants.toList();
+    _remoteParticipants.clear();
     for (final participant in participants) {
       await participant.removeAllPublishedTracks(notify: false);
       // RemoteParticipant is responsible for disposing resources
       await participant.dispose();
     }
-    _remoteParticipants.clear();
-    _sidToIdentity.clear();
     _pendingTrackQueue.clear();
 
     // clean up LocalParticipant
@@ -1101,11 +1085,11 @@ extension RoomHardwareManagementMethods on Room {
   /// Set audio output device.
   Future<void> setAudioOutputDevice(MediaDevice device) async {
     if (lkPlatformIs(PlatformType.web)) {
-      remoteParticipants.forEach((_, participant) {
-        for (var audioTrack in participant.audioTrackPublications) {
+      for (final participant in _remoteParticipants) {
+        for (final audioTrack in participant.audioTrackPublications) {
           audioTrack.track?.setSinkId(device.deviceId);
         }
-      });
+      }
       Hardware.instance.selectedAudioOutput = device;
     } else {
       await Hardware.instance.selectAudioOutput(device);