WIP: [objective_c] Experimenting with isolate group shared

.github/workflows/ffigen.yml

@@ -34,17 +34,17 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
-          channel: 'stable'
+          channel: master
       - id: install
         name: Install dependencies
-        run: flutter pub get && flutter pub get --directory="example/shared_bindings" && flutter pub get --directory="../objective_c"
+        run: dart pub get && dart pub get --directory="example/shared_bindings" && dart pub get --directory="../objective_c"
       - name: Check formatting
         run: dart format --output=none --set-exit-if-changed .
         if: always() && steps.install.outcome == 'success'
       - name: Build test dylib and bindings
         run: dart test/setup.dart
       - name: Analyze code
-        run: flutter analyze --fatal-infos
+        run: dart analyze --fatal-infos
 
   test-linux:
     needs: analyze
@@ -56,9 +56,9 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
-          channel: 'stable'
+          channel: master
       - name: Install dependencies
-        run: flutter pub get && flutter pub get --directory="../jni"
+        run: dart pub get && flutter pub get --directory="../jni"
       - name: Install libclang-14-dev
         run: sudo apt-get install libclang-14-dev
       - name: Build test dylib and bindings
@@ -80,9 +80,9 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
-          channel: stable
+          channel: master
       - name: Install dependencies
-        run: flutter pub get && flutter pub get --directory="../objective_c" && flutter pub get --directory="../jni"
+        run: dart pub get && dart pub get --directory="../objective_c" && flutter pub get --directory="../jni"
       - name: Install clang-format
         uses: ConorMacBride/install-package@3e7ad059e07782ee54fa35f827df52aae0626f30
         with:
@@ -122,7 +122,7 @@ jobs:
         with:
           channel: master
       - name: Install dependencies
-        run: flutter pub get && flutter pub get --directory="../objective_c" && flutter pub get --directory="../jni"
+        run: dart pub get && dart pub get --directory="../objective_c" && flutter pub get --directory="../jni"
       - name: Install clang-format
         uses: ConorMacBride/install-package@3e7ad059e07782ee54fa35f827df52aae0626f30
         with:
@@ -142,13 +142,13 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
-          channel: 'stable'
+          channel: master
       - name: Install dependencies
-        run: flutter pub get && flutter pub get --directory="../objective_c"
+        run: dart pub get && dart pub get --directory="../objective_c"
       - name: Build test dylib and bindings
-        run: dart test/setup.dart --main-thread-dispatcher
+        run: dart test/setup.dart
       - name: Run Flutter tests
-        run: flutter test
+        run: dart test
 
   test-windows:
     needs: analyze
@@ -160,9 +160,9 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
-          channel: 'stable'
+          channel: master
       - name: Install dependencies
-        run: flutter pub get && flutter pub get --directory="../jni"
+        run: dart pub get && flutter pub get --directory="../jni"
       - name: Build test dylib and bindings
         run: dart test/setup.dart
       - name: Run VM tests
@@ -191,7 +191,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
-          channel: "master"
+          channel: master
       - name: Install dependencies
         run: flutter pub get
       - name: Build test dylib and bindings

.github/workflows/ffigen_weekly.yml

@@ -30,17 +30,17 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
-          channel: 'stable'
+          channel: master
       - name: Install dependencies
-        run: flutter pub get && flutter pub get --directory="../objective_c" && flutter pub get --directory="../jni"
+        run: dart pub get && dart pub get --directory="../objective_c" && flutter pub get --directory="../jni"
       - name: Install clang-format
         uses: ConorMacBride/install-package@3e7ad059e07782ee54fa35f827df52aae0626f30
         with:
           brew: clang-format
       - name: Build test dylib and bindings
-        run: dart test/setup.dart --main-thread-dispatcher
+        run: dart test/setup.dart
       - name: Run VM tests
-        run: flutter test
+        run: dart test
       - name: Generate package:jni bindings
         run: dart run tool/generate_ffi_bindings.dart
         working-directory: pkgs/jni/

.github/workflows/objective_c.yaml

@@ -31,17 +31,17 @@ jobs:
       fail-fast: false
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
+      - uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2123f0ab2c02c
         with:
-          channel: 'stable'
+          sdk: dev
       - id: install
         name: Install dependencies
-        run: flutter pub get
+        run: dart pub get
       - name: Check formatting
         run: dart format --output=none --set-exit-if-changed .
         if: always() && steps.install.outcome == 'success'
       - name: Analyze code
-        run: flutter analyze --fatal-infos
+        run: dart analyze --fatal-infos
         if: always() && steps.install.outcome == 'success'
 
   test-mac:
@@ -52,14 +52,11 @@ jobs:
         working-directory: pkgs/objective_c/
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
+      - uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2123f0ab2c02c
         with:
-          channel: 'stable'
+          sdk: dev
       - name: Install dependencies
-        run: flutter pub get
-      - name: Build test dylib
-        # TODO(https://github.com/dart-lang/native/issues/1068): Remove this.
-        run: dart test/setup.dart
+        run: dart pub get
       - name: Install coverage
         run: dart pub global activate coverage
       - name: Run VM tests and collect coverage
@@ -87,13 +84,13 @@ jobs:
     runs-on: 'macos-latest'
     defaults:
       run:
-        working-directory: pkgs/objective_c/example/
+        working-directory: pkgs/objective_c/example
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
+      - uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2123f0ab2c02c
         with:
-          channel: 'stable'
+          sdk: dev
       - name: Install dependencies
-        run: flutter pub get
-      - name: Build the example app
-        run: flutter build macos
+        run: dart pub get
+      - name: Run the example app
+        run: dart run lib/main.dart

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

@@ -141,11 +141,20 @@ class ObjCBlock extends BindingType {
     final closureCallable = w.topLevelUniqueNamer.makeUnique(
       '_${name}_closureCallable',
     );
+    final sharedTrampoline = w.topLevelUniqueNamer.makeUnique(
+      '_${name}_sharedTrampoline',
+    );
+    final sharedCallable = w.topLevelUniqueNamer.makeUnique(
+      '_${name}_sharedCallable',
+    );
     final listenerTrampoline = w.topLevelUniqueNamer.makeUnique(
       '_${name}_listenerTrampoline',
     );
-    final listenerCallable = w.topLevelUniqueNamer.makeUnique(
-      '_${name}_listenerCallable',
+    final listenerPort = w.topLevelUniqueNamer.makeUnique(
+      '_${name}_listenerPort',
+    );
+    final listenerSendPort = w.topLevelUniqueNamer.makeUnique(
+      '_${name}_listenerSendPort',
     );
     final blockingTrampoline = w.topLevelUniqueNamer.makeUnique(
       '_${name}_blockingTrampoline',
@@ -163,6 +172,7 @@ class ObjCBlock extends BindingType {
     final newPointerBlock = ObjCBuiltInFunctions.newPointerBlock.gen(w);
     final newClosureBlock = ObjCBuiltInFunctions.newClosureBlock.gen(w);
     final getBlockClosure = ObjCBuiltInFunctions.getBlockClosure.gen(w);
+    final retainFn = ObjCBuiltInFunctions.objectRetain.gen(w);
     final releaseFn = ObjCBuiltInFunctions.objectRelease.gen(w);
     final objCContext = ObjCBuiltInFunctions.objCContext.gen(w);
     final signalWaiterFn = ObjCBuiltInFunctions.signalWaiter.gen(w);
@@ -194,14 +204,30 @@ $voidPtrCType $closureCallable = ${w.ffiLibraryPrefix}.Pointer.fromFunction<
 
     if (hasListener) {
       // Write the listener trampoline function.
+      final retains = <String>['$retainFn(block.cast()).cast()'];
+      for (var i = 0; i < params.length; ++i) {
+        final param = params[i];
+        final argName = 'arg$i';
+        retains.add(param.type.generateDartRetain(w, argName) ?? argName);
+      }
       s.write('''
-$returnFfiDartType $listenerTrampoline(
+$returnFfiDartType $sharedTrampoline(
     $blockCType block, ${func.paramsFfiDartType}) {
+  final msg = (${retains.join(', ')});
+  $listenerSendPort.send(msg);
+}
+${func.trampNatCallType} $sharedCallable =
+    ${func.trampNatCallType}.isolateGroupShared(
+        $sharedTrampoline $exceptionalReturn)..keepIsolateAlive = false;
+$returnFfiDartType $listenerTrampoline(dynamic msg) {
+  final ${params.isEmpty ? '$blockCType block' : '($blockCType block, ${func.paramsFfiDartType})'} = msg;
   ($getBlockClosure(block) as ${func.ffiDartType})(${func.paramsNameOnly});
   $releaseFn(block.cast());
 }
-${func.trampNatCallType} $listenerCallable = ${func.trampNatCallType}.listener(
-    $listenerTrampoline $exceptionalReturn)..keepIsolateAlive = false;
+final $listenerPort = RawReceivePort(
+    $listenerTrampoline)..keepIsolateAlive = false;
+@pragma('vm:shared')
+final $listenerSendPort = $listenerPort.sendPort;
 $returnFfiDartType $blockingTrampoline(
     $blockCType block, ${blockingFunc.paramsFfiDartType}) {
   try {
@@ -295,7 +321,6 @@ abstract final class $name {
       );
       final listenerConvFn =
           '(${func.paramsFfiDartType}) => $listenerConvFnInvocation';
-      final wrapListenerFn = _blockWrappers!.listenerWrapper.name;
       final wrapBlockingFn = _blockWrappers!.blockingWrapper.name;
 
       s.write('''
@@ -311,11 +336,10 @@ abstract final class $name {
   /// until it is garbage collected by both Dart and ObjC.
   static $blockType listener(${func.dartType} fn,
           {bool keepIsolateAlive = true}) {
-    final raw = $newClosureBlock($listenerCallable.nativeFunction.cast(),
+    final tramp = $newClosureBlock($sharedCallable.nativeFunction.cast(),
         $listenerConvFn, keepIsolateAlive);
-    final wrapper = $wrapListenerFn(raw);
-    $releaseFn(raw.cast());
-    return $blockType(wrapper, retain: false, release: true);
+    print('listener send port: ' + $listenerSendPort.toString());
+    return $blockType(tramp, retain: true, release: true);
   }
 
   /// Creates a blocking block from a Dart function.
@@ -419,7 +443,6 @@ ref.pointer.ref.invoke.cast<${func.trampNatFnCType}>()
       ...argsReceived,
     ].join(', ');
 
-    final listenerWrapper = _blockWrappers!.listenerWrapper.name;
     final blockingWrapper = _blockWrappers!.blockingWrapper.name;
     final listenerName = UniqueNamer.cSafeName(
       w.objCLevelUniqueNamer.makeUnique('ListenerTrampoline'),
@@ -431,14 +454,6 @@ ref.pointer.ref.invoke.cast<${func.trampNatFnCType}>()
     return '''
 
 typedef ${returnType.getNativeType()} (^$listenerName)($argStr);
-__attribute__((visibility("default"))) __attribute__((used))
-$listenerName $listenerWrapper($listenerName block) NS_RETURNS_RETAINED {
-  return ^void($argStr) {
-    ${generateRetain('block')};
-    block(${retains.join(', ')});
-  };
-}
-
 typedef ${returnType.getNativeType()} (^$blockingName)($blockingArgStr);
 __attribute__((visibility("default"))) __attribute__((used))
 $listenerName $blockingWrapper(
@@ -532,6 +547,10 @@ $ret $fnName(id target, $argRecv) {
   @override
   String? generateRetain(String value) => 'objc_retainBlock($value)';
 
+  @override
+  String? generateDartRetain(Writer w, String value) =>
+      '${ObjCBuiltInFunctions.blockRetain.gen(w)}($value.cast()).cast()';
+
   @override
   String toString() =>
       '($returnType (^)(${params.map((p) => p.type.toString()).join(', ')}))';

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

@@ -32,6 +32,8 @@ class ObjCBuiltInFunctions {
     'getProtocolMethodSignature',
   );
   static const getProtocol = ObjCImport('getProtocol');
+  static const blockRetain = ObjCImport('blockRetain');
+  static const objectRetain = ObjCImport('objectRetain');
   static const objectRelease = ObjCImport('objectRelease');
   static const signalWaiter = ObjCImport('signalWaiter');
   static const objCContext = ObjCImport('objCContext');

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

@@ -131,12 +131,3 @@ const objCBuiltInCategories = {
   'NSNumberIsFloat',
   'NSStringExtensionMethods',
 };
-
-const objCBuiltInGlobals = {
-  'NSKeyValueChangeIndexesKey',
-  'NSKeyValueChangeKindKey',
-  'NSKeyValueChangeNewKey',
-  'NSKeyValueChangeNotificationIsPriorKey',
-  'NSKeyValueChangeOldKey',
-  'NSLocalizedDescriptionKey',
-};

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

@@ -214,6 +214,10 @@ ${generateAsStub ? '' : _generateMethods(w)}
   String? generateRetain(String value) =>
       '(__bridge id)(__bridge_retained void*)($value)';
 
+  @override
+  String? generateDartRetain(Writer w, String value) =>
+      '${ObjCBuiltInFunctions.objectRetain.gen(w)}($value)';
+
   @override
   void visit(Visitation visitation) => visitation.visitObjCInterface(this);
 

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

@@ -94,6 +94,10 @@ class ObjCNullable extends Type {
   @override
   String? generateRetain(String value) => child.generateRetain(value);
 
+  @override
+  String? generateDartRetain(Writer w, String value) =>
+      child.generateDartRetain(w, value);
+
   @override
   String toString() => '$child?';
 

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

@@ -352,6 +352,10 @@ Protocol* _${wrapName}_$originalName(void) { return @protocol($originalName); }
   String? generateRetain(String value) =>
       '(__bridge id)(__bridge_retained void*)($value)';
 
+  @override
+  String? generateDartRetain(Writer w, String value) =>
+      '${ObjCBuiltInFunctions.objectRetain.gen(w)}($value)';
+
   bool _isSuperProtocolOf(ObjCProtocol protocol) {
     if (protocol == this) return true;
     for (final superProtocol in protocol.superProtocols) {

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

@@ -154,6 +154,10 @@ class ObjCObjectPointer extends PointerType {
   String? generateRetain(String value) =>
       '(__bridge id)(__bridge_retained void*)($value)';
 
+  @override
+  String? generateDartRetain(Writer w, String value) =>
+      '${ObjCBuiltInFunctions.objectRetain.gen(w)}($value)';
+
   @override
   bool isSupertypeOf(Type other) {
     other = other.typealiasType;
@@ -177,6 +181,10 @@ class ObjCBlockPointer extends ObjCObjectPointer {
   @override
   String? generateRetain(String value) => 'objc_retainBlock($value)';
 
+  @override
+  String? generateDartRetain(Writer w, String value) =>
+      '${ObjCBuiltInFunctions.blockRetain.gen(w)}($value.cast()).cast()';
+
   @override
   bool isSupertypeOf(Type other) {
     other = other.typealiasType;

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

@@ -114,6 +114,10 @@ abstract class Type extends AstNode {
   /// Returns null if the Type does not need to be retained.
   String? generateRetain(String value) => null;
 
+  /// Returns generated Dart code that retains a reference to the given value.
+  /// Returns null if the Type does not need to be retained.
+  String? generateDartRetain(Writer w, String value) => null;
+
   /// Returns a human readable string representation of the Type. This is mostly
   /// just for debugging, but it may also be used for non-functional code (eg to
   /// name a variable or type in generated code).
@@ -230,6 +234,9 @@ abstract class BindingType extends NoLookUpBinding implements Type {
   @override
   String? generateRetain(String value) => null;
 
+  @override
+  String? generateDartRetain(Writer w, String value) => null;
+
   @override
   String toString() => originalName;