Fixes

pkgs/ffigen/lib/src/code_generator/objc_built_in_functions.dart

@@ -119,6 +119,10 @@ class ObjCBuiltInFunctions {
     'NSURLBookmarkResolutionOptions',
     'NSURLHandleStatus',
   };
+  @visibleForTesting
+  static const builtInProtocols = {
+    'NSStreamDelegate',
+  };
 
   // TODO(https://github.com/dart-lang/native/issues/1173): Ideally this check
   // would be based on more than just the name.
@@ -128,8 +132,9 @@ class ObjCBuiltInFunctions {
       generateForPackageObjectiveC ? null : builtInCompounds[name];
   bool isBuiltInEnum(String name) =>
       !generateForPackageObjectiveC && builtInEnums.contains(name);
+  bool isBuiltInProtocol(String name) =>
+      !generateForPackageObjectiveC && builtInProtocols.contains(name);
   bool isNSObject(String name) => name == 'NSObject';
-
   // We need to load a separate instance of objc_msgSend for each signature. If
   // the return type is a struct, we need to use objc_msgSend_stret instead, and
   // for float return types we need objc_msgSend_fpret.

pkgs/ffigen/lib/src/code_generator/objc_protocol.dart

@@ -32,10 +32,11 @@ class ObjCProtocol extends NoLookUpBinding with ObjCMethods {
 
   @override
   void sort() => sortMethods();
+  bool get _isBuiltIn => builtInFunctions.isBuiltInProtocol(originalName);
 
   @override
   BindingString toBindingString(Writer w) {
-    if (!generateBindings) {
+    if (!generateBindings || _isBuiltIn) {
       return const BindingString(
           type: BindingStringType.objcProtocol, string: '');
     }

pkgs/objective_c/ffigen_objc.yaml

@@ -61,6 +61,9 @@ objc-interfaces:
     - NSURLHandle
     - NSValue
     - Protocol
+objc-protocols:
+  include:
+    - NSStreamDelegate
 structs:
   include:
     - _NSRange

pkgs/objective_c/lib/objective_c.dart

@@ -75,6 +75,7 @@ export 'src/objective_c_bindings_generated.dart'
         NSSet,
         NSSortOptions,
         NSStream,
+        NSStreamDelegate,
         NSStreamEvent,
         NSStreamStatus,
         NSString,

pkgs/objective_c/lib/src/objective_c_bindings_generated.dart

@@ -8314,6 +8314,67 @@ class NSStream extends NSObject {
   }
 }
 
+/// NSStreamDelegate
+abstract final class NSStreamDelegate {
+  /// Builds an object that implements the NSStreamDelegate protocol. To implement
+  /// multiple protocols, use [addToBuilder] or [objc.ObjCProtocolBuilder] directly.
+  static objc.ObjCObjectBase implement(
+      {void Function(NSStream, NSStreamEvent)? stream_handleEvent_}) {
+    final builder = objc.ObjCProtocolBuilder();
+    NSStreamDelegate.stream_handleEvent_
+        .implement(builder, stream_handleEvent_);
+    return builder.build();
+  }
+
+  /// Adds the implementation of the NSStreamDelegate protocol to an existing
+  /// [objc.ObjCProtocolBuilder].
+  static void addToBuilder(objc.ObjCProtocolBuilder builder,
+      {void Function(NSStream, NSStreamEvent)? stream_handleEvent_}) {
+    NSStreamDelegate.stream_handleEvent_
+        .implement(builder, stream_handleEvent_);
+  }
+
+  /// Builds an object that implements the NSStreamDelegate protocol. To implement
+  /// multiple protocols, use [addToBuilder] or [objc.ObjCProtocolBuilder] directly. All
+  /// methods that can be implemented as listeners will be.
+  static objc.ObjCObjectBase implementAsListener(
+      {void Function(NSStream, NSStreamEvent)? stream_handleEvent_}) {
+    final builder = objc.ObjCProtocolBuilder();
+    NSStreamDelegate.stream_handleEvent_
+        .implementAsListener(builder, stream_handleEvent_);
+    return builder.build();
+  }
+
+  /// Adds the implementation of the NSStreamDelegate protocol to an existing
+  /// [objc.ObjCProtocolBuilder]. All methods that can be implemented as listeners will
+  /// be.
+  static void addToBuilderAsListener(objc.ObjCProtocolBuilder builder,
+      {void Function(NSStream, NSStreamEvent)? stream_handleEvent_}) {
+    NSStreamDelegate.stream_handleEvent_
+        .implementAsListener(builder, stream_handleEvent_);
+  }
+
+  /// stream:handleEvent:
+  static final stream_handleEvent_ =
+      objc.ObjCProtocolListenableMethod<void Function(NSStream, NSStreamEvent)>(
+    _sel_stream_handleEvent_,
+    objc.getProtocolMethodSignature(
+      _protocol_NSStreamDelegate,
+      _sel_stream_handleEvent_,
+      isRequired: false,
+      isInstanceMethod: true,
+    ),
+    (void Function(NSStream, NSStreamEvent) func) =>
+        ObjCBlock_ffiVoid_ffiVoid_NSStream_NSStreamEvent.fromFunction(
+            (ffi.Pointer<ffi.Void> _, NSStream arg1, NSStreamEvent arg2) =>
+                func(arg1, arg2)),
+    (void Function(NSStream, NSStreamEvent) func) =>
+        ObjCBlock_ffiVoid_ffiVoid_NSStream_NSStreamEvent.listener(
+            (ffi.Pointer<ffi.Void> _, NSStream arg1, NSStreamEvent arg2) =>
+                func(arg1, arg2)),
+  );
+}
+
 enum NSStreamEvent {
   NSStreamEventNone(0),
   NSStreamEventOpenCompleted(1),
@@ -15498,6 +15559,7 @@ final _objc_msgSend_z1lin0 = objc.msgSendPointer
     .asFunction<
         bool Function(ffi.Pointer<objc.ObjCObject>,
             ffi.Pointer<objc.ObjCSelector>, ffi.Pointer<ffi.Char>, int)>();
+late final _protocol_NSStreamDelegate = objc.getProtocol("NSStreamDelegate");
 late final _sel_URLByAppendingPathComponent_ =
     objc.registerName("URLByAppendingPathComponent:");
 late final _sel_URLByAppendingPathComponent_isDirectory_ =

pkgs/objective_c/src/input_stream_adapter.m

@@ -162,8 +162,7 @@ - (BOOL)hasBytesAvailable {
 - (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {
   id<NSStreamDelegate> delegate = _delegate;
   if (delegate != self) {
-    os_log_with_type(OS_LOG_DEFAULT, OS_LOG_TYPE_ERROR,
-                     "DartInputStreamAdapter: non-self delegate was invoked");
+    [delegate stream:self handleEvent:streamEvent];
   }
 }
 

pkgs/objective_c/test/interface_lists_test.dart

@@ -19,6 +19,7 @@ void main() {
     late List<String> yamlInterfaces;
     late List<String> yamlStructs;
     late List<String> yamlEnums;
+    late List<String> yamlProtocols;
 
     setUpAll(() {
       final yaml =
@@ -38,6 +39,11 @@ void main() {
           .map<String>((dynamic i) => i as String)
           .toList()
         ..sort();
+      yamlProtocols = ((yaml['objc-protocols'] as YamlMap)['include']
+              as YamlList)
+          .map<String>((dynamic i) => i as String)
+          .toList()
+        ..sort();
     });
 
     test('ObjCBuiltInFunctions.builtInInterfaces', () {
@@ -52,6 +58,10 @@ void main() {
       expect(ObjCBuiltInFunctions.builtInEnums, yamlEnums);
     });
 
+    test('ObjCBuiltInFunctions.builtInProtocols', () {
+      expect(ObjCBuiltInFunctions.builtInProtocols, yamlProtocols);
+    });
+
     test('package:objective_c exports all the interfaces', () {
       final exportFile = File('lib/objective_c.dart').readAsStringSync();
       for (final intf in yamlInterfaces) {
@@ -75,6 +85,13 @@ void main() {
       }
     });
 
+    test('package:objective_c exports all the protocols', () {
+      final exportFile = File('lib/objective_c.dart').readAsStringSync();
+      for (final protocol in yamlProtocols) {
+        expect(exportFile, contains(protocol));
+      }
+    });
+
     test('All code genned interfaces are included in the list', () {
       final classNameRegExp = RegExp(r'^class (\w+) ');
       final allClassNames = <String>[];
@@ -119,5 +136,19 @@ void main() {
       }
       expect(allEnumNames, unorderedEquals(yamlEnums));
     });
+
+    test('All code genned protocols are included in the list', () {
+      final protocolNameRegExp =
+          RegExp(r'^abstract final class (?!ObjCBlock_)(\w+) {');
+      final allProtocolNames = <String>[];
+      for (final line in File('lib/src/objective_c_bindings_generated.dart')
+          .readAsLinesSync()) {
+        final match = protocolNameRegExp.firstMatch(line);
+        if (match != null) {
+          allProtocolNames.add(match[1]!);
+        }
+      }
+      expect(allProtocolNames, unorderedEquals(yamlProtocols));
+    });
   });
 }

pkgs/objective_c/test/ns_input_stream_test.dart

@@ -14,6 +14,7 @@ import 'dart:typed_data';
 
 import 'package:ffi/ffi.dart';
 import 'package:objective_c/objective_c.dart';
+import 'package:objective_c/src/objective_c_bindings_generated.dart';
 import 'package:test/test.dart';
 
 Future<(int, Uint8List, bool, NSStreamStatus, NSError?)> read(
@@ -244,25 +245,30 @@ void main() {
   });
 
   group('delegate', () {
-    late NSInputStream inputStream;
+    late DartInputStreamAdapter inputStream;
 
     setUp(() {
       inputStream = Stream.fromIterable([
         [1, 2, 3],
-      ]).toNSInputStream();
+      ]).toNSInputStream() as DartInputStreamAdapter;
     });
 
     test('default delegate', () async {
       expect(inputStream.delegate, inputStream);
+      inputStream.stream_handleEvent_(
+          inputStream, NSStreamEvent.NSStreamEventOpenCompleted);
     });
 
-    test('assign to non-self', () async {
-      inputStream.delegate = [1, 2, 3].toNSData();
-      inputStream.open();
-      final (count, data, hasBytesAvailable, status, error) =
-          await read(inputStream, 3);
-      expect(count, 3);
-      expect(error, null);
+    test('non-self delegate', () async {
+      final protoBuilder = ObjCProtocolBuilder();
+      final events = <NSStreamEvent>[];
+
+      NSStreamDelegate.addToBuilder(protoBuilder,
+          stream_handleEvent_: (stream, event) => events.add(event));
+      inputStream.delegate = protoBuilder.build();
+      inputStream.stream_handleEvent_(
+          inputStream, NSStreamEvent.NSStreamEventOpenCompleted);
+      expect(events, [NSStreamEvent.NSStreamEventOpenCompleted]);
     });
 
     test('assign to null', () async {