[ffigen] Add protocol methods to interfaces

pkgs/ffigen/CHANGELOG.md

@@ -1,6 +1,9 @@
-## 14.1.0-wip
+## 15.0.0-wip
 
 - Dedupe `ObjCBlock` trampolines to reduce generated ObjC code.
+- ObjC objects now include the methods from the protocols they implement. Both
+  required and optional methods are included. Optional methods will throw an
+  exception if the method isn't implemented.
 
 ## 14.0.1
 

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

@@ -21,6 +21,7 @@ class ObjCBuiltInFunctions {
   static const msgSendFpretPointer = ObjCImport('msgSendFpretPointer');
   static const msgSendStretPointer = ObjCImport('msgSendStretPointer');
   static const useMsgSendVariants = ObjCImport('useMsgSendVariants');
+  static const respondsToSelector = ObjCImport('respondsToSelector');
   static const newPointerBlock = ObjCImport('newPointerBlock');
   static const newClosureBlock = ObjCImport('newClosureBlock');
   static const getBlockClosure = ObjCImport('getBlockClosure');
@@ -37,6 +38,8 @@ class ObjCBuiltInFunctions {
       ObjCImport('ObjCProtocolListenableMethod');
   static const protocolBuilder = ObjCImport('ObjCProtocolBuilder');
   static const dartProxy = ObjCImport('DartProxy');
+  static const unimplementedOptionalMethodException =
+      ObjCImport('UnimplementedOptionalMethodException');
 
   // Keep in sync with pkgs/objective_c/ffigen_objc.yaml.
   static const builtInInterfaces = {

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

@@ -41,6 +41,7 @@ class ObjCInterface extends BindingType with ObjCMethods {
   late final ObjCInternalGlobal _classObject;
   late final ObjCInternalGlobal _isKindOfClass;
   late final ObjCMsgSendFunc _isKindOfClassMsgSend;
+  final _protocols = <ObjCProtocol>[];
 
   @override
   final ObjCBuiltInFunctions builtInFunctions;
@@ -55,6 +56,7 @@ class ObjCInterface extends BindingType with ObjCMethods {
   })  : lookupName = lookupName ?? originalName,
         super(name: name ?? originalName);
 
+  void addProtocol(ObjCProtocol proto) => _protocols.add(proto);
   bool get _isBuiltIn => builtInFunctions.isBuiltInInterface(originalName);
 
   @override
@@ -185,6 +187,15 @@ class ObjCInterface extends BindingType with ObjCMethods {
       s.write(' {\n');
 
       // Implementation.
+      final sel = m.selObject!.name;
+      if (m.isOptional) {
+        s.write('''
+    if (!${ObjCBuiltInFunctions.respondsToSelector.gen(w)}(ref.pointer, $sel)) {
+      throw ${ObjCBuiltInFunctions.unimplementedOptionalMethodException.gen(w)}(
+          '$originalName', '${m.originalName}');
+    }
+''');
+      }
       final convertReturn = m.kind != ObjCMethodKind.propertySetter &&
           !returnType.sameDartAndFfiDartType;
 
@@ -201,7 +212,7 @@ class ObjCInterface extends BindingType with ObjCMethods {
                   objCRetain: m.consumesSelf,
                   objCAutorelease: false,
                 ),
-          m.selObject!.name,
+          sel,
           m.params.map((p) => p.type.convertDartTypeToFfiDartType(
                 w,
                 p.name,
@@ -252,10 +263,17 @@ class ObjCInterface extends BindingType with ObjCMethods {
       superType!.addDependencies(dependencies);
       _copyMethodsFromSuperType();
       _fixNullabilityOfOverriddenMethods();
+    }
 
-      // Add dependencies for any methods that were added.
-      addMethodDependencies(dependencies, needMsgSend: true);
+    for (final proto in _protocols) {
+      proto.addDependencies(dependencies);
+      for (final m in proto.methods) {
+        addMethod(m);
+      }
     }
+
+    // Add dependencies for any methods that were added.
+    addMethodDependencies(dependencies, needMsgSend: true);
   }
 
   void _copyMethodsFromSuperType() {

pkgs/ffigen/lib/src/header_parser/sub_parsers/objcinterfacedecl_parser.dart

@@ -12,6 +12,7 @@ import '../data.dart';
 import '../includer.dart';
 import '../utils.dart';
 import 'api_availability.dart';
+import 'objcprotocoldecl_parser.dart';
 
 final _logger = Logger('ffigen.header_parser.objcinterfacedecl_parser');
 
@@ -76,6 +77,9 @@ void _fillInterface(ObjCInterface itf, clang_types.CXCursor cursor) {
       case clang_types.CXCursorKind.CXCursor_ObjCSuperClassRef:
         _parseSuperType(child, itf);
         break;
+      case clang_types.CXCursorKind.CXCursor_ObjCProtocolRef:
+        _parseProtocol(child, itf);
+        break;
       case clang_types.CXCursorKind.CXCursor_ObjCPropertyDecl:
         _parseProperty(child, itf, itfDecl);
         break;
@@ -112,6 +116,14 @@ void _parseSuperType(clang_types.CXCursor cursor, ObjCInterface itf) {
   }
 }
 
+void _parseProtocol(clang_types.CXCursor cursor, ObjCInterface itf) {
+  final protoCursor = clang.clang_getCursorDefinition(cursor);
+  final proto = parseObjCProtocolDeclaration(protoCursor);
+  if (proto != null) {
+    itf.addProtocol(proto);
+  }
+}
+
 void _parseProperty(
     clang_types.CXCursor cursor, ObjCInterface itf, Declaration itfDecl) {
   final fieldName = cursor.spelling();

pkgs/ffigen/pubspec.yaml

@@ -3,7 +3,7 @@
 # BSD-style license that can be found in the LICENSE file.
 
 name: ffigen
-version: 14.1.0-wip
+version: 15.0.0-wip
 description: >
   Generator for FFI bindings, using LibClang to parse C, Objective-C, and Swift
   files.

pkgs/ffigen/test/large_integration_tests/large_objc_test.dart

@@ -6,7 +6,7 @@
 @TestOn('mac-os')
 
 // This is a slow test.
-@Timeout(Duration(minutes: 2))
+@Timeout(Duration(minutes: 5))
 library;
 
 import 'dart:async';
@@ -28,7 +28,7 @@ Future<int> run(String exe, List<String> args) async {
 
 void main() {
   test('Large ObjC integration test', () async {
-    // Reducing the bindings to a random subset to that the test completes in a
+    // Reducing the bindings to a random subset so that the test completes in a
     // reasonable amount of time.
     // TODO(https://github.com/dart-lang/sdk/issues/56247): Remove this.
     const inclusionRatio = 0.1;
@@ -41,10 +41,12 @@ void main() {
 
     // TODO(https://github.com/dart-lang/native/issues/1220): Allow these.
     const disallowedMethods = {
-      'cachePolicy',
+      'accessKey',
       'allowsConstrainedNetworkAccess',
-      'tag',
+      'attributedString',
+      'cachePolicy',
       'hyphenationFactor',
+      'tag',
     };
     final interfaceFilter = DeclarationFilters(
       shouldInclude: randInclude,

pkgs/ffigen/test/native_objc_test/protocol_config.yaml

@@ -15,6 +15,6 @@ objc-protocols:
     - SecondaryProtocol
 headers:
   entry-points:
-    - 'protocol_test.m'
+    - 'protocol_test.h'
 preamble: |
   // ignore_for_file: camel_case_types, non_constant_identifier_names, unnecessary_non_null_assertion, unused_element, unused_field

pkgs/ffigen/test/native_objc_test/protocol_test.dart

@@ -9,6 +9,7 @@ import 'dart:async';
 import 'dart:ffi';
 import 'dart:io';
 
+import 'package:ffi/ffi.dart';
 import 'package:objective_c/objective_c.dart';
 import 'package:test/test.dart';
 
@@ -50,6 +51,27 @@ void main() {
         expect(otherIntResult, 10);
       });
 
+      test('Method implementation, invoke from Dart', () {
+        final protocolImpl = ObjCProtocolImpl.new1();
+
+        // Required instance method.
+        final result =
+            protocolImpl.instanceMethod_withDouble_("abc".toNSString(), 123);
+        expect(result.toString(), 'ObjCProtocolImpl: abc: 123.00');
+
+        // Optional instance method.
+        final structPtr = calloc<SomeStruct>();
+        structPtr.ref.x = 12;
+        structPtr.ref.y = 34;
+        final intResult = protocolImpl.optionalMethod_(structPtr.ref);
+        expect(intResult, 46);
+        calloc.free(structPtr);
+
+        // Required instance method from secondary protocol.
+        final otherIntResult = protocolImpl.otherMethod_b_c_d_(2, 4, 6, 8);
+        expect(otherIntResult, 20);
+      });
+
       test('Unimplemented method', () {
         final protocolImpl = ObjCProtocolImplMissingMethod.new1();
         final consumer = ProtocolConsumer.new1();
@@ -58,6 +80,18 @@ void main() {
         final intResult = consumer.callOptionalMethod_(protocolImpl);
         expect(intResult, -999);
       });
+
+      test('Unimplemented method, invoke from Dart', () {
+        final protocolImpl = ObjCProtocolImplMissingMethod.new1();
+
+        // Optional instance method, not implemented.
+        final structPtr = calloc<SomeStruct>();
+        structPtr.ref.x = 12;
+        structPtr.ref.y = 34;
+        expect(() => protocolImpl.optionalMethod_(structPtr.ref),
+            throwsA(isA<UnimplementedOptionalMethodException>()));
+        calloc.free(structPtr);
+      });
     });
 
     group('Dart implementation using helpers', () {

pkgs/ffigen/test/native_objc_test/protocol_test.h

@@ -0,0 +1,60 @@
+// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#import <Foundation/NSObject.h>
+#import <Foundation/NSString.h>
+
+#include "util.h"
+
+typedef struct {
+  int32_t x;
+  int32_t y;
+} SomeStruct;
+
+@protocol SuperProtocol<NSObject>
+
+@required
+- (NSString*)instanceMethod:(NSString*)s withDouble:(double)x;
+
+@end
+
+@protocol MyProtocol<SuperProtocol>
+
+@optional
+- (int32_t)optionalMethod:(SomeStruct)s;
+
+@optional
+- (void)voidMethod:(int32_t)x;
+
+@end
+
+
+@protocol SecondaryProtocol<NSObject>
+
+@required
+- (int32_t)otherMethod:(int32_t)a b:(int32_t)b c:(int32_t)c d:(int32_t)d;
+
+@optional
+- (nullable instancetype)returnsInstanceType;
+
+@end
+
+@protocol EmptyProtocol
+@end
+
+
+@interface ProtocolConsumer : NSObject
+- (NSString*)callInstanceMethod:(id<MyProtocol>)protocol;
+- (int32_t)callOptionalMethod:(id<MyProtocol>)protocol;
+- (int32_t)callOtherMethod:(id<SecondaryProtocol>)protocol;
+- (void)callMethodOnRandomThread:(id<SecondaryProtocol>)protocol;
+@end
+
+
+@interface ObjCProtocolImpl : NSObject<MyProtocol, SecondaryProtocol>
+@end
+
+
+@interface ObjCProtocolImplMissingMethod : NSObject<MyProtocol>
+@end

pkgs/ffigen/test/native_objc_test/protocol_test.m

@@ -3,55 +3,10 @@
 // BSD-style license that can be found in the LICENSE file.
 
 #import <dispatch/dispatch.h>
-#import <Foundation/NSObject.h>
-#import <Foundation/NSString.h>
 
+#include "protocol_test.h"
 #include "util.h"
 
-typedef struct {
-  int32_t x;
-  int32_t y;
-} SomeStruct;
-
-@protocol SuperProtocol<NSObject>
-
-@required
-- (NSString*)instanceMethod:(NSString*)s withDouble:(double)x;
-
-@end
-
-@protocol MyProtocol<SuperProtocol>
-
-@optional
-- (int32_t)optionalMethod:(SomeStruct)s;
-
-@optional
-- (void)voidMethod:(int32_t)x;
-
-@end
-
-
-@protocol SecondaryProtocol<NSObject>
-
-@required
-- (int32_t)otherMethod:(int32_t)a b:(int32_t)b c:(int32_t)c d:(int32_t)d;
-
-@optional
-- (nullable instancetype)returnsInstanceType;
-
-@end
-
-@protocol EmptyProtocol
-@end
-
-
-@interface ProtocolConsumer : NSObject
-- (NSString*)callInstanceMethod:(id<MyProtocol>)protocol;
-- (int32_t)callOptionalMethod:(id<MyProtocol>)protocol;
-- (int32_t)callOtherMethod:(id<SecondaryProtocol>)protocol;
-- (void)callMethodOnRandomThread:(id<SecondaryProtocol>)protocol;
-@end
-
 @implementation ProtocolConsumer : NSObject
 - (NSString*)callInstanceMethod:(id<MyProtocol>)protocol {
   return [protocol instanceMethod:@"Hello from ObjC" withDouble:3.14];
@@ -78,9 +33,6 @@ - (void)callMethodOnRandomThread:(id<MyProtocol>)protocol {
 @end
 
 
-@interface ObjCProtocolImpl : NSObject<MyProtocol, SecondaryProtocol>
-@end
-
 @implementation ObjCProtocolImpl
 - (NSString *)instanceMethod:(NSString *)s withDouble:(double)x {
   return [NSString stringWithFormat:@"ObjCProtocolImpl: %@: %.2f", s, x];
@@ -97,9 +49,6 @@ - (int32_t)otherMethod:(int32_t)a b:(int32_t)b c:(int32_t)c d:(int32_t)d {
 @end
 
 
-@interface ObjCProtocolImplMissingMethod : NSObject<MyProtocol>
-@end
-
 @implementation ObjCProtocolImplMissingMethod
 - (NSString *)instanceMethod:(NSString *)s withDouble:(double)x {
   return @"ObjCProtocolImplMissingMethod";

pkgs/objective_c/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 2.1.0-wip
+
+- Add `UnimplementedOptionalMethodException`, which is thrown by the ObjC
+  bindings if an optional method is invoked, and the instance doesn't implement
+  the method.
+
 ## 2.0.0
 
 - Drop API methods that are deprecated in the oldest versions of iOS and macOS