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Use NSProxy to implement ObjC protocols (#1144)
1 parent 413dd27 commit e5dee44

24 files changed

+2135
-1230
lines changed

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

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@@ -27,6 +27,8 @@ class ObjCBuiltInFunctions {
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// Keep in sync with pkgs/objective_c/ffigen_objc.yaml.
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static const builtInInterfaces = {
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'DartProxy',
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'DartProxyBuilder',
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'NSArray',
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'NSCharacterSet',
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'NSCoder',
@@ -49,6 +51,7 @@ class ObjCBuiltInFunctions {
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'NSNumber',
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'NSObject',
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'NSProgress',
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'NSProxy',
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'NSSet',
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'NSString',
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'NSURL',

‎pkgs/ffigen/test/native_objc_test/is_instance_test.dart

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// BSD-style license that can be found in the LICENSE file.
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// Objective C support is only available on mac.
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@TestOn('mac-os')
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import 'dart:ffi';

‎pkgs/ffigen/test/native_objc_test/protocol_config.yaml

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name: ProtocolTestObjCLibrary
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description: 'Tests implementing protocols'
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language: objc
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output: 'protocol_bindings.dart'
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exclude-all-by-default: true
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objc-interfaces:
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include:
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- ProtocolConsumer
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- ObjCProtocolImpl
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- ObjCProtocolImplMissingMethod
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typedefs:
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include:
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- InstanceMethodBlock
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- OptMethodBlock
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- VoidMethodBlock
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- OtherMethodBlock
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functions:
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include:
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- forceCodeGenOfInstanceMethodBlock
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- forceCodeGenOfOptMethodBlock
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- forceCodeGenOfVoidMethodBlock
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- forceCodeGenOfOtherMethodBlock
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headers:
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entry-points:
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- 'protocol_test.m'
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preamble: |
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// 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

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// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Objective C support is only available on mac.
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@TestOn('mac-os')
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import 'dart:async';
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import 'dart:ffi';
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import 'dart:io';
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import 'package:objective_c/objective_c.dart';
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import 'package:test/test.dart';
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import '../test_utils.dart';
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import 'protocol_bindings.dart';
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import 'util.dart';
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void main() {
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group('protocol', () {
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setUpAll(() {
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logWarnings();
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// TODO(https://github.com/dart-lang/native/issues/1068): Remove this.
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DynamicLibrary.open('../objective_c/test/objective_c.dylib');
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final dylib = File('test/native_objc_test/protocol_test.dylib');
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verifySetupFile(dylib);
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DynamicLibrary.open(dylib.absolute.path);
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generateBindingsForCoverage('protocol');
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});
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group('ObjC implementation', () {
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test('Method implementation', () {
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final protoImpl = ObjCProtocolImpl.new1();
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final consumer = ProtocolConsumer.new1();
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// Required instance method.
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final result = consumer.callInstanceMethod_(protoImpl);
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expect(result.toString(), 'ObjCProtocolImpl: Hello from ObjC: 3.14');
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// Optional instance method.
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final intResult = consumer.callOptionalMethod_(protoImpl);
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expect(intResult, 579);
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// Required instance method from secondary protocol.
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final otherIntResult = consumer.callOtherMethod_(protoImpl);
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expect(otherIntResult, 10);
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});
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test('Unimplemented method', () {
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final protoImpl = ObjCProtocolImplMissingMethod.new1();
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final consumer = ProtocolConsumer.new1();
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// Optional instance method, not implemented.
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final intResult = consumer.callOptionalMethod_(protoImpl);
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expect(intResult, -999);
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});
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});
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group('Manual DartProxy implementation', () {
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test('Method implementation', () {
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final proxyBuilder = DartProxyBuilder.new1();
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final consumer = ProtocolConsumer.new1();
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final proto = getProtocol('MyProtocol');
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final secondProto = getProtocol('SecondaryProtocol');
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final sel = registerName('instanceMethod:withDouble:');
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final signature = getProtocolMethodSignature(proto, sel,
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isRequired: true, isInstance: true);
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final block = DartInstanceMethodBlock.fromFunction(
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(Pointer<Void> p, NSString s, double x) {
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return 'DartProxy: $s: $x'.toNSString();
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});
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proxyBuilder.implementMethod_withSignature_andBlock_(
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sel, signature!, block.pointer.cast());
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final optSel = registerName('optionalMethod:');
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final optSignature = getProtocolMethodSignature(proto, optSel,
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isRequired: false, isInstance: true);
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final optBlock =
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DartOptMethodBlock.fromFunction((Pointer<Void> p, SomeStruct s) {
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return s.y - s.x;
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});
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proxyBuilder.implementMethod_withSignature_andBlock_(
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optSel, optSignature!, optBlock.pointer.cast());
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final otherSel = registerName('otherMethod:b:c:d:');
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final otherSignature = getProtocolMethodSignature(secondProto, otherSel,
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isRequired: true, isInstance: true);
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final otherBlock = DartOtherMethodBlock.fromFunction(
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(Pointer<Void> p, int a, int b, int c, int d) {
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return a * b * c * d;
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});
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proxyBuilder.implementMethod_withSignature_andBlock_(
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otherSel, otherSignature!, otherBlock.pointer.cast());
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final proxy = DartProxy.newFromBuilder_(proxyBuilder);
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// Required instance method.
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final result = consumer.callInstanceMethod_(proxy);
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expect(result.toString(), "DartProxy: Hello from ObjC: 3.14");
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// Optional instance method.
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final intResult = consumer.callOptionalMethod_(proxy);
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expect(intResult, 333);
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// Required instance method from secondary protocol.
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final otherIntResult = consumer.callOtherMethod_(proxy);
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expect(otherIntResult, 24);
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});
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test('Unimplemented method', () {
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final proxyBuilder = DartProxyBuilder.new1();
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final consumer = ProtocolConsumer.new1();
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final proxy = DartProxy.newFromBuilder_(proxyBuilder);
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// Optional instance method, not implemented.
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final intResult = consumer.callOptionalMethod_(proxy);
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expect(intResult, -999);
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});
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test('Threading stress test', () async {
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final proxyBuilder = DartProxyBuilder.new1();
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final consumer = ProtocolConsumer.new1();
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final proto = getProtocol('MyProtocol');
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final completer = Completer<void>();
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int count = 0;
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final sel = registerName('voidMethod:');
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final signature = getProtocolMethodSignature(proto, sel,
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isRequired: false, isInstance: true);
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final block = DartVoidMethodBlock.listener((Pointer<Void> p, int x) {
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expect(x, 123);
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++count;
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if (count == 1000) completer.complete();
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});
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proxyBuilder.implementMethod_withSignature_andBlock_(
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sel, signature!, block.pointer.cast());
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final proxy = DartProxy.newFromBuilder_(proxyBuilder);
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for (int i = 0; i < 1000; ++i) {
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consumer.callMethodOnRandomThread_(proxy);
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}
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await completer.future;
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expect(count, 1000);
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});
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(DartProxy, Pointer<ObjCBlock>) blockRefCountTestInner() {
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final proxyBuilder = DartProxyBuilder.new1();
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final proto = getProtocol('MyProtocol');
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final sel = registerName('instanceMethod:withDouble:');
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final signature = getProtocolMethodSignature(proto, sel,
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isRequired: true, isInstance: true);
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final block = DartInstanceMethodBlock.fromFunction(
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(Pointer<Void> p, NSString s, double x) => 'Hello'.toNSString());
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proxyBuilder.implementMethod_withSignature_andBlock_(
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sel, signature!, block.pointer.cast());
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final proxy = DartProxy.newFromBuilder_(proxyBuilder);
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final proxyPtr = proxy.pointer;
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final blockPtr = block.pointer;
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// There are 2 references to the block. One owned by the Dart wrapper
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// object, and the other owned by the proxy. The method signature is
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// also an ObjC object, so the same is true for it.
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doGC();
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expect(objectRetainCount(proxyPtr), 1);
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expect(blockRetainCount(blockPtr), 2);
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return (proxy, blockPtr);
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}
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(Pointer<ObjCObject>, Pointer<ObjCBlock>) blockRefCountTest() {
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final (proxy, blockPtr) = blockRefCountTestInner();
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final proxyPtr = proxy.pointer;
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// The Dart side block pointer has gone out of scope, but the proxy
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// still owns a reference to it. Same for the signature.
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doGC();
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expect(objectRetainCount(proxyPtr), 1);
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expect(blockRetainCount(blockPtr), 1);
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return (proxyPtr, blockPtr);
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}
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test('Block ref counting', () {
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final (proxyPtr, blockPtr) = blockRefCountTest();
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// The proxy object has gone out of scope, so it should be cleaned up.
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// So should the block and the signature.
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doGC();
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expect(objectRetainCount(proxyPtr), 0);
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expect(blockRetainCount(blockPtr), 0);
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});
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});
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});
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}

‎pkgs/ffigen/test/native_objc_test/protocol_test.m

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// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#import <dispatch/dispatch.h>
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#import <Foundation/NSObject.h>
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#import <Foundation/NSString.h>
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#include "util.h"
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typedef struct {
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int32_t x;
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int32_t y;
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} SomeStruct;
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@protocol MyProtocol<NSObject>
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@required
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- (NSString*)instanceMethod:(NSString*)s withDouble:(double)x;
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@optional
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- (int32_t)optionalMethod:(SomeStruct)s;
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@optional
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- (void)voidMethod:(int32_t)x;
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@end
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@protocol SecondaryProtocol<NSObject>
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@required
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- (int32_t)otherMethod:(int32_t)a b:(int32_t)b c:(int32_t)c d:(int32_t)d;
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@end
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@interface ProtocolConsumer : NSObject
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- (NSString*)callInstanceMethod:(id<MyProtocol>)proto;
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- (int32_t)callOptionalMethod:(id<MyProtocol>)proto;
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- (int32_t)callOtherMethod:(id<SecondaryProtocol>)proto;
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- (void)callMethodOnRandomThread:(id<SecondaryProtocol>)proto;
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@end
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@implementation ProtocolConsumer : NSObject
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- (NSString*)callInstanceMethod:(id<MyProtocol>)proto {
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return [proto instanceMethod:@"Hello from ObjC" withDouble:3.14];
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}
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- (int32_t)callOptionalMethod:(id<MyProtocol>)proto {
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if ([proto respondsToSelector:@selector(optionalMethod:)]) {
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SomeStruct s = {123, 456};
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return [proto optionalMethod:s];
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} else {
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return -999;
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}
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}
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- (int32_t)callOtherMethod:(id<SecondaryProtocol>)proto {
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return [proto otherMethod:1 b:2 c:3 d:4];
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}
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- (void)callMethodOnRandomThread:(id<MyProtocol>)proto {
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dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0), ^{
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[proto voidMethod:123];
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});
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}
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@end
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@interface ObjCProtocolImpl : NSObject<MyProtocol, SecondaryProtocol>
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@end
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@implementation ObjCProtocolImpl
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- (NSString *)instanceMethod:(NSString *)s withDouble:(double)x {
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return [NSString stringWithFormat:@"ObjCProtocolImpl: %@: %.2f", s, x];
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}
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- (int32_t)optionalMethod:(SomeStruct)s {
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return s.x + s.y;
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}
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- (int32_t)otherMethod:(int32_t)a b:(int32_t)b c:(int32_t)c d:(int32_t)d {
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return a + b + c + d;
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}
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@end
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@interface ObjCProtocolImplMissingMethod : NSObject<MyProtocol>
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@end
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@implementation ObjCProtocolImplMissingMethod
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- (NSString *)instanceMethod:(NSString *)s withDouble:(double)x {
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return @"ObjCProtocolImplMissingMethod";
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}
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@end
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// TODO(https://github.com/dart-lang/native/issues/1040): Delete these.
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typedef NSString* (^InstanceMethodBlock)(void*, NSString*, double);
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void forceCodeGenOfInstanceMethodBlock(InstanceMethodBlock block);
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typedef int32_t (^OptMethodBlock)(void*, SomeStruct);
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void forceCodeGenOfOptMethodBlock(OptMethodBlock block);
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typedef void (^VoidMethodBlock)(void*, int32_t);
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void forceCodeGenOfVoidMethodBlock(VoidMethodBlock block);
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typedef int32_t (^OtherMethodBlock)(void*, int32_t a, int32_t b, int32_t c, int32_t d);
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void forceCodeGenOfOtherMethodBlock(OtherMethodBlock block);

‎pkgs/objective_c/.gitignore

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*.pyc
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*.swp
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*.dylib
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*.o
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.DS_Store
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.atom/
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.buildlog/

‎pkgs/objective_c/CHANGELOG.md

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## 1.1.0-wip
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- Add `DartProxy`, which is an implementation of `NSProxy` that enables
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implementing ObjC protocols from Dart. Also adds `DartProxyBuilder` for
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constructing `DartProxy`.
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## 1.0.1
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- Mention experimental status in readme.

‎pkgs/objective_c/example/pubspec.lock

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path: ".."
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relative: true
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source: path
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version: "0.0.1-wip"
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version: "1.0.0"
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path:
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dependency: transitive
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description:

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