Fix dart2wasm standalone exports

example/web/main.dart

@@ -25,6 +25,7 @@ Future<Element> runTests(String source, String name) async {
   container.append(
     createKeyVal('Size of Pointer', runner.pointerSize().toString()),
   );
+  container.append(createKeyVal('Sum4', runner.sum4().toString()));
   container.append(
     createKeyVal('Static Init Check', runner.staticInitCheck().toString()),
   );

example_flutter/Makefile

@@ -6,6 +6,7 @@ build: assets/standalone/native_example.wasm assets/emscripten/native_example.js
 
 SRC=src/native_example.c src/native_example_cpp.cpp
 DEPS=$(SRC) $(SRC:.c=.h)
+EMCC ?= emcc
 
 # Wasm options
 ifdef  DEBUG
@@ -22,16 +23,16 @@ clean:
 	rm -rf assets/emscripten/*
 
 lib/native_example_bindings.dart: $(DEPS)
-	dart run ffigen --config ffigen.yaml && sed -i "s#'dart:ffi'#'package:wasm_ffi/ffi.dart'#g" $@
+	dart run ffigen --config ffigen.yaml && perl -pi -e "s#(['\"])dart:ffi\\1#'package:wasm_ffi/ffi.dart'#g" $@
 
 assets/standalone/native_example.wasm: $(DEPS) lib/native_example_bindings.dart
-	emcc -o assets/standalone/native_example.wasm $(COMPILER_OPTIONS) $(LINKER_OPTIONS) \
+	$(EMCC) -o assets/standalone/native_example.wasm $(COMPILER_OPTIONS) $(LINKER_OPTIONS) \
 		$(SRC) \
 		-s STANDALONE_WASM=1 \
 		-s $(COMPILED_EXPORTS)
 
 assets/emscripten/native_example.js: $(DEPS) lib/native_example_bindings.dart
-	emcc -o assets/emscripten/native_example.js $(COMPILER_OPTIONS) $(LINKER_OPTIONS) \
+	$(EMCC) -o assets/emscripten/native_example.js $(COMPILER_OPTIONS) $(LINKER_OPTIONS) \
 		$(SRC) \
 		-s MODULARIZE=1 -s 'EXPORT_NAME="native_example"' -s ALLOW_MEMORY_GROWTH=1 \
 		-s EXPORTED_RUNTIME_METHODS=HEAPU8 \

example_flutter/lib/example_library_wrapper.dart

@@ -32,5 +32,7 @@ class ExampleLibraryWrapper {
 
   int pointerSize() => bindings.pointerSize();
 
+  int sum4() => bindings.sum4(1, 2, 3, 4);
+
   bool staticInitCheck() => bindings.static_init_check() != 0;
 }

example_flutter/lib/main.dart

@@ -70,6 +70,7 @@ class _AsyncRunnerWidgetState extends State<AsyncRunnerWidget> {
       'Size of Int': runner.intSize().toString(),
       'Size of Bool': runner.boolSize().toString(),
       'Size of Pointer': runner.pointerSize().toString(),
+      'Sum4': runner.sum4().toString(),
       'Static Init Check': runner.staticInitCheck().toString(),
     };
   }

example_flutter/lib/native_example_bindings.dart

@@ -87,6 +87,17 @@ class NativeExampleBindings {
   );
   late final _pointerSize = _pointerSizePtr.asFunction<int Function()>();
 
+  /// sum four numbers
+  int sum4(int a, int b, int c, int d) {
+    return _sum4(a, b, c, d);
+  }
+
+  late final _sum4Ptr =
+      _lookup<
+        ffi.NativeFunction<ffi.Int Function(ffi.Int, ffi.Int, ffi.Int, ffi.Int)>
+      >('sum4');
+  late final _sum4 = _sum4Ptr.asFunction<int Function(int, int, int, int)>();
+
   /// check if static initialization happened
   int static_init_check() {
     return _static_init_check();

example_flutter/src/native_example.c

@@ -42,3 +42,9 @@ EXPORT int pointerSize(void)
 {
   return (int)sizeof(void*);
 }
+
+/// sum four numbers
+EXPORT int sum4(int a, int b, int c, int d)
+{
+  return a + b + c + d;
+}

example_flutter/src/native_example.h

@@ -33,11 +33,14 @@ EXPORT int boolSize(void);
 /// size of a pointer
 EXPORT int pointerSize(void);
 
+/// sum four numbers
+EXPORT int sum4(int a, int b, int c, int d);
+
 /// check if static initialization happened
 EXPORT int static_init_check(void);
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif
+#endif

lib/src/ffi/extensions.dart

@@ -1,4 +1,3 @@
-import 'dart:js_interop';
 import 'dart:typed_data';
 import 'annotations.dart';
 import 'exceptions.dart';
@@ -21,9 +20,8 @@ extension NativeFunctionPointer<NF extends Function>
   DF asFunction<DF extends Function>() {
     // ignore: prefer_final_locals
     WasmSymbol symbol = symbolByAddress(boundMemory, address);
-    if (symbol is FunctionDescription && symbol.function.isA<JSFunction>()) {
-      // ignore: invalid_runtime_check_with_js_interop_types
-      return marshall<NF, DF>(symbol.function as Function, boundMemory);
+    if (symbol is FunctionDescription) {
+      return marshall<NF, DF>(symbol.function, boundMemory);
     } else {
       throw ArgumentError(
         'No function at address $address was found (but a global symbol)!',

lib/src/ffi/invoker_generated.dart

@@ -12,7 +12,7 @@ class OpaqueInvokeHelper<T extends Opaque> extends InvokeHelper<Pointer<T>> {
   OpaqueInvokeHelper(super.base, super.memory);
 
   @override
-  InvokeHelper<Pointer<T>> copyWith(Function base, Memory memory) {
+  InvokeHelper<Pointer<T>> copyWith(Object base, Memory memory) {
     return OpaqueInvokeHelper<T>(base, memory);
   }
 
@@ -282,7 +282,7 @@ class OpaqueInvokeHelperSquare<T extends Opaque>
   OpaqueInvokeHelperSquare(super.base, super.memory);
 
   @override
-  InvokeHelper<Pointer<Pointer<T>>> copyWith(Function base, Memory memory) {
+  InvokeHelper<Pointer<Pointer<T>>> copyWith(Object base, Memory memory) {
     return OpaqueInvokeHelperSquare<T>(base, memory);
   }
 
@@ -549,11 +549,11 @@ class OpaqueInvokeHelperSquare<T extends Opaque>
 
 class InvokeHelper<T> {
   final Memory? _memory;
-  final Function? _base;
+  final Object? _base;
 
   const InvokeHelper(this._base, this._memory);
 
-  InvokeHelper<T> copyWith(Function base, Memory memory) {
+  InvokeHelper<T> copyWith(Object base, Memory memory) {
     return InvokeHelper(base, memory);
   }
 
@@ -688,7 +688,7 @@ class InvokeHelper<T> {
     if (_base == null || _memory == null) {
       throw StateError('Call copyWith first!');
     }
-    final Function base = _base;
+    final Object base = _base;
     final Memory memory = _memory;
     final List<Object> args = [
       arg0,

lib/src/ffi/js_function_apply.dart

@@ -0,0 +1,2 @@
+export 'js_function_apply_stub.dart'
+    if (dart.library.js_interop) 'js_function_apply_web.dart';

lib/src/ffi/js_function_apply_stub.dart

@@ -0,0 +1,33 @@
+import 'exceptions.dart';
+import 'memory.dart';
+import 'types.dart';
+
+Object? applyJsFunction(
+  Object base,
+  List<Object> args, [
+  Set<int> jsBigIntArgumentIndexes = const {},
+]) {
+  throw const MarshallingException(
+    'JavaScript function invocation is only available in JavaScript runtimes!',
+  );
+}
+
+Object? toJsFunctionArgument(Object dartObject, {bool asBigInt = false}) {
+  if (dartObject is int || dartObject is double || dartObject is bool) {
+    return dartObject;
+  } else if (dartObject is Pointer) {
+    return dartObject.address;
+  }
+
+  throw MarshallingException(
+    'Could not convert dart type ${dartObject.runtimeType} to a JavaScript type!',
+  );
+}
+
+T jsResultToDartType<T>(
+  Object result,
+  Memory memory,
+  R Function<R>(Object value, Memory memory) toDartType,
+) {
+  return toDartType<T>(result, memory);
+}

lib/src/ffi/js_function_apply_web.dart

@@ -0,0 +1,93 @@
+import 'dart:js_interop';
+import 'dart:js_interop_unsafe';
+
+import 'exceptions.dart';
+import 'memory.dart';
+import 'types.dart';
+
+@JS('BigInt')
+external JSBigInt _bigInt(JSAny? obj);
+
+extension type _WrappedJSAny._(JSAny _) implements JSAny {
+  @JS('toString')
+  external JSString _toString();
+}
+
+Object? applyJsFunction(
+  Object base,
+  List<Object> args, [
+  Set<int> jsBigIntArgumentIndexes = const {},
+]) {
+  final jsFunction = base as JSFunction;
+  final JSFunction apply = (jsFunction as JSObject).getProperty<JSFunction>(
+    'apply'.toJS,
+  );
+  final jsArgs = <JSAny?>[
+    for (var i = 0; i < args.length; i++)
+      _toJsAny(args[i], asBigInt: jsBigIntArgumentIndexes.contains(i)),
+  ];
+  return apply.callAsFunction(jsFunction, null, jsArgs.toJS);
+}
+
+Object? toJsFunctionArgument(Object dartObject, {bool asBigInt = false}) {
+  return _toJsAny(dartObject, asBigInt: asBigInt);
+}
+
+T jsResultToDartType<T>(
+  Object result,
+  Memory memory,
+  R Function<R>(Object value, Memory memory) toDartType,
+) {
+  final jsResult = result as JSAny;
+  if (T == int) {
+    if (jsResult.typeofEquals('number')) {
+      return (jsResult as JSNumber).toDartInt as T;
+    }
+    if (jsResult.typeofEquals('bigint')) {
+      return _jsBigIntToDartInt(jsResult) as T;
+    }
+  } else if (T == double) {
+    if (jsResult.typeofEquals('number')) {
+      return (jsResult as JSNumber).toDartDouble as T;
+    }
+  } else if (T == bool) {
+    if (jsResult.typeofEquals('boolean')) {
+      return (jsResult as JSBoolean).toDart as T;
+    }
+    if (jsResult.typeofEquals('number')) {
+      return toDartType<T>((jsResult as JSNumber).toDartInt, memory);
+    }
+  } else if (jsResult.typeofEquals('number')) {
+    return toDartType<T>((jsResult as JSNumber).toDartInt, memory);
+  } else if (jsResult.typeofEquals('bigint')) {
+    return toDartType<T>(_jsBigIntToDartInt(jsResult), memory);
+  }
+
+  final Object? dartified = jsResult.dartify();
+  if (dartified == null) {
+    return null as T;
+  }
+  return toDartType<T>(dartified, memory);
+}
+
+int _jsBigIntToDartInt(JSAny jsBigInt) {
+  return BigInt.parse((jsBigInt as _WrappedJSAny)._toString().toDart).toInt();
+}
+
+JSAny? _toJsAny(Object dartObject, {bool asBigInt = false}) {
+  if (dartObject is int) {
+    return asBigInt ? _bigInt(dartObject.toString().toJS) : dartObject.toJS;
+  } else if (dartObject is double) {
+    return dartObject.toJS;
+  } else if (dartObject is bool) {
+    return dartObject.toJS;
+  } else if (dartObject is Pointer) {
+    return asBigInt
+        ? _bigInt(dartObject.address.toString().toJS)
+        : dartObject.address.toJS;
+  } else {
+    throw MarshallingException(
+      'Could not convert dart type ${dartObject.runtimeType} to a JavaScript type!',
+    );
+  }
+}