[video_player_avfoundation] Create a Dart player instance (#10490)

Refactors the Dart internals to create a pleyer instance class on the Dart side, and intermediates the event stream with an instance-managed stream controller that would allow for alternate event sources (e.g., Dart code).

This prepares for future moves of more logic to Dart, and parallels Android Dart code changes made in
#9771

Part of flutter/flutter#172763

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: stuartmorgan-g

packages/video_player/video_player_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.8.8
+
+* Refactors Dart internals for maintainability.
+
 ## 2.8.7
 
 * Updates to Pigeon 26.

packages/video_player/video_player_avfoundation/darwin/video_player_avfoundation/Sources/video_player_avfoundation/FVPVideoPlayerPlugin.m

@@ -116,7 +116,7 @@ - (int64_t)configurePlayer:(FVPVideoPlayer *)player
   // Set up the event channel.
   FVPEventBridge *eventBridge = [[FVPEventBridge alloc]
       initWithMessenger:messenger
-            channelName:[NSString stringWithFormat:@"flutter.io/videoPlayer/videoEvents%@",
+            channelName:[NSString stringWithFormat:@"flutter.dev/videoPlayer/videoEvents%@",
                                                    channelSuffix]];
   player.eventListener = eventBridge;
 

packages/video_player/video_player_avfoundation/lib/src/avfoundation_video_player.dart

@@ -22,23 +22,16 @@ class AVFoundationVideoPlayer extends VideoPlayerPlatform {
   AVFoundationVideoPlayer({
     @visibleForTesting AVFoundationVideoPlayerApi? pluginApi,
     @visibleForTesting
-    VideoPlayerInstanceApi Function(int playerId)? playerProvider,
+    VideoPlayerInstanceApi Function(int playerId)? playerApiProvider,
   }) : _api = pluginApi ?? AVFoundationVideoPlayerApi(),
-       _playerProvider = playerProvider ?? _productionApiProvider;
+       _playerApiProvider = playerApiProvider ?? _productionApiProvider;
 
   final AVFoundationVideoPlayerApi _api;
   // A method to create VideoPlayerInstanceApi instances, which can be
   // overridden for testing.
-  final VideoPlayerInstanceApi Function(int mapId) _playerProvider;
+  final VideoPlayerInstanceApi Function(int mapId) _playerApiProvider;
 
-  /// A map that associates player ID with a view state.
-  /// This is used to determine which view type to use when building a view.
-  @visibleForTesting
-  final Map<int, VideoPlayerViewState> playerViewStates =
-      <int, VideoPlayerViewState>{};
-
-  final Map<int, VideoPlayerInstanceApi> _players =
-      <int, VideoPlayerInstanceApi>{};
+  final Map<int, _PlayerInstance> _players = <int, _PlayerInstance>{};
 
   /// Registers this class as the default instance of [VideoPlayerPlatform].
   static void registerWith() {
@@ -52,9 +45,8 @@ class AVFoundationVideoPlayer extends VideoPlayerPlatform {
 
   @override
   Future<void> dispose(int playerId) async {
-    final VideoPlayerInstanceApi? player = _players.remove(playerId);
+    final _PlayerInstance? player = _players.remove(playerId);
     await player?.dispose();
-    playerViewStates.remove(playerId);
   }
 
   @override
@@ -118,18 +110,24 @@ class AVFoundationVideoPlayer extends VideoPlayerPlatform {
         playerId = await _api.createForPlatformView(pigeonCreationOptions);
         state = const VideoPlayerPlatformViewState();
     }
-    playerViewStates[playerId] = state;
-    ensureApiInitialized(playerId);
+    ensurePlayerInitialized(playerId, state);
 
     return playerId;
   }
 
   /// Returns the API instance for [playerId], creating it if it doesn't already
   /// exist.
   @visibleForTesting
-  VideoPlayerInstanceApi ensureApiInitialized(int playerId) {
-    return _players.putIfAbsent(playerId, () {
-      return _playerProvider(playerId);
+  void ensurePlayerInitialized(int playerId, VideoPlayerViewState viewState) {
+    _players.putIfAbsent(playerId, () {
+      return _PlayerInstance(
+        _playerApiProvider(playerId),
+        viewState,
+        eventChannel: EventChannel(
+          // This must match the channel name used in FVPVideoPlayerPlugin.m.
+          'flutter.dev/videoPlayer/videoEvents$playerId',
+        ),
+      );
     });
   }
 
@@ -162,48 +160,17 @@ class AVFoundationVideoPlayer extends VideoPlayerPlatform {
 
   @override
   Future<void> seekTo(int playerId, Duration position) {
-    return _playerWith(id: playerId).seekTo(position.inMilliseconds);
+    return _playerWith(id: playerId).seekTo(position);
   }
 
   @override
   Future<Duration> getPosition(int playerId) async {
-    final int position = await _playerWith(id: playerId).getPosition();
-    return Duration(milliseconds: position);
+    return _playerWith(id: playerId).getPosition();
   }
 
   @override
   Stream<VideoEvent> videoEventsFor(int playerId) {
-    return _eventChannelFor(playerId).receiveBroadcastStream().map((
-      dynamic event,
-    ) {
-      final map = event as Map<dynamic, dynamic>;
-      return switch (map['event']) {
-        'initialized' => VideoEvent(
-          eventType: VideoEventType.initialized,
-          duration: Duration(milliseconds: map['duration'] as int),
-          size: Size(
-            (map['width'] as num?)?.toDouble() ?? 0.0,
-            (map['height'] as num?)?.toDouble() ?? 0.0,
-          ),
-        ),
-        'completed' => VideoEvent(eventType: VideoEventType.completed),
-        'bufferingUpdate' => VideoEvent(
-          buffered: (map['values'] as List<dynamic>)
-              .map<DurationRange>(_toDurationRange)
-              .toList(),
-          eventType: VideoEventType.bufferingUpdate,
-        ),
-        'bufferingStart' => VideoEvent(
-          eventType: VideoEventType.bufferingStart,
-        ),
-        'bufferingEnd' => VideoEvent(eventType: VideoEventType.bufferingEnd),
-        'isPlayingStateUpdate' => VideoEvent(
-          eventType: VideoEventType.isPlayingStateUpdate,
-          isPlaying: map['isPlaying'] as bool,
-        ),
-        _ => VideoEvent(eventType: VideoEventType.unknown),
-      };
-    });
+    return _playerWith(id: playerId).videoEvents;
   }
 
   @override
@@ -219,16 +186,13 @@ class AVFoundationVideoPlayer extends VideoPlayerPlatform {
   @override
   Widget buildViewWithOptions(VideoViewOptions options) {
     final int playerId = options.playerId;
-    final VideoPlayerViewState? viewState = playerViewStates[playerId];
+    final VideoPlayerViewState viewState = _playerWith(id: playerId).viewState;
 
     return switch (viewState) {
       VideoPlayerTextureViewState(:final int textureId) => Texture(
         textureId: textureId,
       ),
       VideoPlayerPlatformViewState() => _buildPlatformView(playerId),
-      null => throw Exception(
-        'Could not find corresponding view type for playerId: $playerId',
-      ),
     };
   }
 
@@ -245,13 +209,90 @@ class AVFoundationVideoPlayer extends VideoPlayerPlatform {
     );
   }
 
-  EventChannel _eventChannelFor(int playerId) {
-    return EventChannel('flutter.io/videoPlayer/videoEvents$playerId');
+  _PlayerInstance _playerWith({required int id}) {
+    final _PlayerInstance? player = _players[id];
+    return player ?? (throw StateError('No active player with ID $id.'));
   }
+}
 
-  VideoPlayerInstanceApi _playerWith({required int id}) {
-    final VideoPlayerInstanceApi? player = _players[id];
-    return player ?? (throw StateError('No active player with ID $id.'));
+/// An instance of a video player, corresponding to a single player ID in
+/// [AVFoundationVideoPlayer].
+class _PlayerInstance {
+  _PlayerInstance(
+    this._api,
+    this.viewState, {
+    required EventChannel eventChannel,
+  }) : _eventChannel = eventChannel;
+
+  final VideoPlayerInstanceApi _api;
+  final VideoPlayerViewState viewState;
+  final EventChannel _eventChannel;
+  final StreamController<VideoEvent> _eventStreamController =
+      StreamController<VideoEvent>.broadcast();
+  StreamSubscription<dynamic>? _eventSubscription;
+
+  Future<void> play() => _api.play();
+
+  Future<void> pause() => _api.pause();
+
+  Future<void> setLooping(bool looping) => _api.setLooping(looping);
+
+  Future<void> setVolume(double volume) => _api.setVolume(volume);
+
+  Future<void> setPlaybackSpeed(double speed) => _api.setPlaybackSpeed(speed);
+
+  Future<void> seekTo(Duration position) {
+    return _api.seekTo(position.inMilliseconds);
+  }
+
+  Future<Duration> getPosition() async {
+    return Duration(milliseconds: await _api.getPosition());
+  }
+
+  Stream<VideoEvent> get videoEvents {
+    _eventSubscription ??= _eventChannel.receiveBroadcastStream().listen(
+      _onStreamEvent,
+      onError: (Object e) {
+        _eventStreamController.addError(e);
+      },
+    );
+
+    return _eventStreamController.stream;
+  }
+
+  Future<void> dispose() async {
+    await _eventSubscription?.cancel();
+    unawaited(_eventStreamController.close());
+    await _api.dispose();
+  }
+
+  void _onStreamEvent(dynamic event) {
+    final map = event as Map<dynamic, dynamic>;
+    // The strings here must all match the strings in FVPEventBridge.m.
+    _eventStreamController.add(switch (map['event']) {
+      'initialized' => VideoEvent(
+        eventType: VideoEventType.initialized,
+        duration: Duration(milliseconds: map['duration'] as int),
+        size: Size(
+          (map['width'] as num?)?.toDouble() ?? 0.0,
+          (map['height'] as num?)?.toDouble() ?? 0.0,
+        ),
+      ),
+      'completed' => VideoEvent(eventType: VideoEventType.completed),
+      'bufferingUpdate' => VideoEvent(
+        buffered: (map['values'] as List<dynamic>)
+            .map<DurationRange>(_toDurationRange)
+            .toList(),
+        eventType: VideoEventType.bufferingUpdate,
+      ),
+      'bufferingStart' => VideoEvent(eventType: VideoEventType.bufferingStart),
+      'bufferingEnd' => VideoEvent(eventType: VideoEventType.bufferingEnd),
+      'isPlayingStateUpdate' => VideoEvent(
+        eventType: VideoEventType.isPlayingStateUpdate,
+        isPlaying: map['isPlaying'] as bool,
+      ),
+      _ => VideoEvent(eventType: VideoEventType.unknown),
+    });
   }
 
   DurationRange _toDurationRange(dynamic value) {

packages/video_player/video_player_avfoundation/pubspec.yaml

@@ -2,7 +2,7 @@ name: video_player_avfoundation
 description: iOS and macOS implementation of the video_player plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/video_player/video_player_avfoundation
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+video_player%22
-version: 2.8.7
+version: 2.8.8
 
 environment:
   sdk: ^3.9.0