Add deprecations to PlatformMessage stuff (flutter#42580)

Fixes old TODOs originally added in flutter#22181.
The framework appears to be fully migrated off these.

lib/ui/channel_buffers.dart

@@ -6,13 +6,18 @@
 // KEEP THIS SYNCHRONIZED WITH ../web_ui/lib/channel_buffers.dart
 part of dart.ui;
 
+/// Deprecated. Migrate to [ChannelCallback] instead.
+///
 /// Signature for [ChannelBuffers.drain]'s `callback` argument.
 ///
 /// The first argument is the data sent by the plugin.
 ///
 /// The second argument is a closure that, when called, will send messages
 /// back to the plugin.
-// TODO(ianh): deprecate this once the framework is migrated to [ChannelCallback].
+@Deprecated(
+  'Migrate to ChannelCallback instead. '
+  'This feature was deprecated after v3.11.0-20.0.pre.',
+)
 typedef DrainChannelCallback = Future<void> Function(ByteData? data, PlatformMessageResponseCallback callback);
 
 /// Signature for [ChannelBuffers.setListener]'s `callback` argument.
@@ -377,14 +382,19 @@ class ChannelBuffers {
     }
   }
 
+  /// Deprecated. Migrate to [setListener] instead.
+  ///
   /// Remove and process all stored messages for a given channel.
   ///
   /// This should be called once a channel is prepared to handle messages
   /// (i.e. when a message handler is set up in the framework).
   ///
   /// The messages are processed by calling the given `callback`. Each message
   /// is processed in its own microtask.
-  // TODO(ianh): deprecate once framework uses [setListener].
+  @Deprecated(
+    'Migrate to setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   Future<void> drain(String name, DrainChannelCallback callback) async {
     final _Channel? channel = _channels[name];
     while (channel != null && !channel._queue.isEmpty) {

lib/ui/platform_dispatcher.dart

@@ -41,8 +41,13 @@ typedef SemanticsActionEventCallback = void Function(SemanticsActionEvent action
 /// [PlatformDispatcher.onPlatformMessage].
 typedef PlatformMessageResponseCallback = void Function(ByteData? data);
 
+/// Deprecated. Migrate to [ChannelBuffers.setListener] instead.
+///
 /// Signature for [PlatformDispatcher.onPlatformMessage].
-// TODO(ianh): deprecate once framework uses [ChannelBuffers.setListener].
+@Deprecated(
+  'Migrate to ChannelBuffers.setListener instead. '
+  'This feature was deprecated after v3.11.0-20.0.pre.',
+)
 typedef PlatformMessageCallback = void Function(String name, ByteData? data, PlatformMessageResponseCallback? callback);
 
 // Signature for _setNeedsReportTimings.
@@ -651,6 +656,8 @@ class PlatformDispatcher {
   @Native<Void Function(Int64)>(symbol: 'PlatformConfigurationNativeApi::RegisterBackgroundIsolate')
   external static void __registerBackgroundIsolate(int rootIsolateId);
 
+  /// Deprecated. Migrate to [ChannelBuffers.setListener] instead.
+  ///
   /// Called whenever this platform dispatcher receives a message from a
   /// platform-specific plugin.
   ///
@@ -664,11 +671,17 @@ class PlatformDispatcher {
   ///
   /// The framework invokes this callback in the same zone in which the callback
   /// was set.
-  // TODO(ianh): Deprecate onPlatformMessage once the framework is moved over
-  // to using channel buffers exclusively.
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   PlatformMessageCallback? get onPlatformMessage => _onPlatformMessage;
   PlatformMessageCallback? _onPlatformMessage;
   Zone _onPlatformMessageZone = Zone.root;
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   set onPlatformMessage(PlatformMessageCallback? callback) {
     _onPlatformMessage = callback;
     _onPlatformMessageZone = Zone.current;

lib/ui/window.dart

@@ -787,6 +787,8 @@ class SingletonFlutterWindow extends FlutterView {
     platformDispatcher.sendPlatformMessage(name, data, callback);
   }
 
+  /// Deprecated. Migrate to [ChannelBuffers.setListener] instead.
+  ///
   /// Called whenever this window receives a message from a platform-specific
   /// plugin.
   ///
@@ -802,8 +804,15 @@ class SingletonFlutterWindow extends FlutterView {
   ///
   /// The framework invokes this callback in the same zone in which the
   /// callback was set.
-  // TODO(ianh): deprecate once framework uses [ChannelBuffers.setListener].
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   PlatformMessageCallback? get onPlatformMessage => platformDispatcher.onPlatformMessage;
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   set onPlatformMessage(PlatformMessageCallback? callback) {
     platformDispatcher.onPlatformMessage = callback;
   }

testing/dart/channel_buffers_test.dart

@@ -31,6 +31,9 @@ void main() {
       called = true;
     }
     buffers.push(channel, data, callback);
+    // Ignoring the deprecated member use because we're specifically testing
+    // deprecated API.
+    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       expect(drainedData, equals(data));
       assert(!called);
@@ -52,6 +55,9 @@ void main() {
 
     // Ignoring the returned future because the completion of the drain is
     // communicated using the `completer`.
+    // Ignoring the deprecated member use because we're specifically testing
+    // deprecated API.
+    // ignore: deprecated_member_use
     buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       log.add('callback');
       completer.complete();
@@ -77,6 +83,9 @@ void main() {
     _resize(buffers, channel, 0);
     buffers.push(channel, data, callback);
     bool didCall = false;
+    // Ignoring the deprecated member use because we're specifically testing
+    // deprecated API.
+    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       didCall = true;
     });
@@ -87,6 +96,9 @@ void main() {
     const String channel = 'foo';
     final ui.ChannelBuffers buffers = ui.ChannelBuffers();
     bool didCall = false;
+    // Ignoring the deprecated member use because we're specifically testing
+    // deprecated API.
+    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       didCall = true;
     });
@@ -107,6 +119,9 @@ void main() {
     buffers.push(channel, three, callback);
     buffers.push(channel, four, callback);
     int counter = 0;
+    // Ignoring the deprecated member use because we're specifically testing
+    // deprecated API.
+    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       switch (counter) {
         case 0:
@@ -132,6 +147,9 @@ void main() {
     buffers.push(channel, two, callback);
     _resize(buffers, channel, 1);
     int counter = 0;
+    // Ignoring the deprecated member use because we're specifically testing
+    // deprecated API.
+    // ignore: deprecated_member_use
     await buffers.drain(channel, (ByteData? drainedData, ui.PlatformMessageResponseCallback drainedCallback) async {
       switch (counter) {
         case 0:

testing/dart/observatory/vmservice_methods_test.dart

@@ -74,12 +74,15 @@ void main() {
         fail('This test must not be run with --disable-vm-service.');
       }
 
-      final Completer<PlatformResponse> completer = Completer<PlatformResponse>();
-      ui.PlatformDispatcher.instance.onPlatformMessage = (String name, ByteData? data, ui.PlatformMessageResponseCallback? callback) {
-        final ByteBuffer buffer = data!.buffer;
-        final Uint8List list = buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
-        completer.complete(PlatformResponse(name: name, contents: utf8.decode(list)));
-      };
+      final Completer<String> completer = Completer<String>();
+      ui.channelBuffers.setListener(
+        'flutter/system',
+        (ByteData? data, ui.PlatformMessageResponseCallback callback) {
+          final ByteBuffer buffer = data!.buffer;
+          final Uint8List list = buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
+          completer.complete(utf8.decode(list));
+        },
+      );
 
       vmService = await vmServiceConnectUri(
         'ws://localhost:${info.serverUri!.port}${info.serverUri!.path}ws',
@@ -94,13 +97,11 @@ void main() {
       expect(fontChangeResponse.type, 'Success');
       expect(
         await completer.future,
-        const PlatformResponse(
-          name: 'flutter/system',
-          contents: '{"type":"fontsChange"}',
-        ),
+        '{"type":"fontsChange"}',
       );
     } finally {
       await vmService?.dispose();
+      ui.channelBuffers.clearListener('flutter/system');
     }
   });
 }
@@ -121,22 +122,3 @@ Future<String?> getIsolateId(vms.VmService vmService) async {
   }
   return null;
 }
-
-class PlatformResponse {
-  const PlatformResponse({
-    required this.name,
-    required this.contents,
-  });
-
-  final String name;
-  final String contents;
-
-  @override
-  bool operator ==(Object other) =>
-      other is PlatformResponse &&
-      other.name == name &&
-      other.contents == contents;
-
-  @override
-  int get hashCode => Object.hash(name, contents);
-}

testing/dart/text_test.dart

@@ -195,20 +195,19 @@ void testTextRange() {
 
 void testLoadFontFromList() {
   test('loadFontFromList will send platform message after font is loaded', () async {
-    final PlatformMessageCallback? oldHandler = PlatformDispatcher.instance.onPlatformMessage;
-    late String actualName;
     late String message;
-    PlatformDispatcher.instance.onPlatformMessage = (String name, ByteData? data, PlatformMessageResponseCallback? callback) {
-      assert(data != null);
-      actualName = name;
-      final Uint8List list = data!.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
-      message = utf8.decode(list);
-    };
+    channelBuffers.setListener(
+      'flutter/system',
+      (ByteData? data, PlatformMessageResponseCallback? callback) {
+        assert(data != null);
+        final Uint8List list = data!.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
+        message = utf8.decode(list);
+      },
+    );
     final Uint8List fontData = Uint8List(0);
     await loadFontFromList(fontData, fontFamily: 'fake');
-    PlatformDispatcher.instance.onPlatformMessage = oldHandler;
-    expect(actualName, 'flutter/system');
     expect(message, '{"type":"fontsChange"}');
+    channelBuffers.clearListener('flutter/system');
   });
 }
 

testing/scenario_app/lib/main.dart

@@ -17,12 +17,13 @@ void main() {
   //   FlutterView to the _view property.
   assert(PlatformDispatcher.instance.implicitView != null);
   PlatformDispatcher.instance
-    ..onPlatformMessage = _handlePlatformMessage
     ..onBeginFrame = _onBeginFrame
     ..onDrawFrame = _onDrawFrame
     ..onMetricsChanged = _onMetricsChanged
     ..onPointerDataPacket = _onPointerDataPacket
     ..scheduleFrame();
+  channelBuffers.setListener('driver', _handleDriverMessage);
+  channelBuffers.setListener('write_timeline', _handleWriteTimelineMessage);
 
   final FlutterView view = PlatformDispatcher.instance.implicitView!;
   // Asserting that this is greater than zero since this app runs on different
@@ -41,7 +42,8 @@ void main() {
 /// The FlutterView into which the [Scenario]s will be rendered.
 FlutterView get _view => PlatformDispatcher.instance.implicitView!;
 
-void _handleDriverMessage(Map<String, dynamic> call) {
+void _handleDriverMessage(ByteData? data, PlatformMessageResponseCallback? callback) {
+  final Map<String, dynamic> call = json.decode(utf8.decode(data!.buffer.asUint8List())) as Map<String, dynamic>;
   final String? methodName = call['method'] as String?;
   switch (methodName) {
     case 'set_scenario':
@@ -52,23 +54,9 @@ void _handleDriverMessage(Map<String, dynamic> call) {
   }
 }
 
-Future<void> _handlePlatformMessage(
-    String name, ByteData? data, PlatformMessageResponseCallback? callback) async {
-  if (data != null) {
-    print('$name = ${utf8.decode(data.buffer.asUint8List())}');
-  } else {
-    print(name);
-  }
-
-  switch (name) {
-    case 'driver':
-      _handleDriverMessage(json.decode(utf8.decode(data!.buffer.asUint8List())) as Map<String, dynamic>);
-    case 'write_timeline':
-      final String timelineData = await _getTimelineData();
-      callback!(Uint8List.fromList(utf8.encode(timelineData)).buffer.asByteData());
-    default:
-      currentScenario?.onPlatformMessage(name, data, callback);
-  }
+Future<void> _handleWriteTimelineMessage(ByteData? data, PlatformMessageResponseCallback? callback) async {
+  final String timelineData = await _getTimelineData();
+  callback!(Uint8List.fromList(utf8.encode(timelineData)).buffer.asByteData());
 }
 
 Future<String> _getTimelineData() async {

testing/scenario_app/lib/src/platform_view.dart

@@ -422,6 +422,7 @@ class MultiPlatformViewBackgroundForegroundScenario extends Scenario
     required this.secondId,
   }) {
     _nextFrame = _firstFrame;
+    channelBuffers.setListener('flutter/lifecycle', _onPlatformMessage);
   }
 
   /// The platform view identifier to use for the first platform view.
@@ -504,15 +505,10 @@ class MultiPlatformViewBackgroundForegroundScenario extends Scenario
 
   String _lastLifecycleState = '';
 
-  @override
-  void onPlatformMessage(
-    String name,
+  void _onPlatformMessage(
     ByteData? data,
     PlatformMessageResponseCallback? callback,
   ) {
-    if (name != 'flutter/lifecycle') {
-      return;
-    }
     final String message = utf8.decode(data!.buffer.asUint8List());
     if (_lastLifecycleState == 'AppLifecycleState.inactive' &&
         message == 'AppLifecycleState.resumed') {
@@ -522,6 +518,12 @@ class MultiPlatformViewBackgroundForegroundScenario extends Scenario
 
     _lastLifecycleState = message;
   }
+
+  @override
+  void unmount() {
+    channelBuffers.clearListener('flutter/lifecycle');
+    super.unmount();
+  }
 }
 
 /// Platform view with clip rect.