Run object default methods for interfaces

dart-lang · Dec 11, 2024 · 9f9a1b5 · 9f9a1b5
1 parent 2cecc88
commit 9f9a1b5
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Showing 3 changed files with 51 additions and 18 deletions.
diff --git a/pkgs/jni/CHANGELOG.md b/pkgs/jni/CHANGELOG.md
@@ -10,6 +10,8 @@
   them in a for-loop or use methods such as `map` on them.
 
 - Added nullable type classes for all Java objects.
+- Fixed a problem where interfaces implemented in Dart would crash when calling
+  the default object methods: `equals`, `hashCode`, and `toString`.
 
 ## 0.12.2
 

diff --git a/pkgs/jni/java/src/main/java/com/github/dart_lang/jni/PortProxyBuilder.java b/pkgs/jni/java/src/main/java/com/github/dart_lang/jni/PortProxyBuilder.java
@@ -9,8 +9,20 @@
 
 public class PortProxyBuilder implements InvocationHandler {
   private static final PortCleaner cleaner = new PortCleaner();
+  private static final Method equals;
+  private static final Method hashCode;
+  private static final Method toString;
 
   static {
+    Class<Object> object = Object.class;
+    try {
+      equals = object.getDeclaredMethod("equals", object);
+      hashCode = object.getDeclaredMethod("hashCode");
+      toString = object.getDeclaredMethod("toString");
+    } catch (NoSuchMethodException e) {
+      // Never happens.
+      throw new Error();
+    }
     System.loadLibrary("dartjni");
   }
 
@@ -73,7 +85,7 @@ private static void appendType(StringBuilder descriptor, Class<?> type) {
   }
 
   public void addImplementation(
-      String binaryName, long port, long functionPointer, List<String> asyncMethods) {
+    String binaryName, long port, long functionPointer, List<String> asyncMethods) {
     implementations.put(binaryName, new DartImplementation(port, functionPointer));
     this.asyncMethods.addAll(asyncMethods);
   }
@@ -91,8 +103,8 @@ public Object build() throws ClassNotFoundException {
       classes.add(Class.forName(binaryName));
     }
     Object obj =
-        Proxy.newProxyInstance(
-            classes.get(0).getClassLoader(), classes.toArray(new Class<?>[0]), this);
+      Proxy.newProxyInstance(
+        classes.get(0).getClassLoader(), classes.toArray(new Class<?>[0]), this);
     for (DartImplementation implementation : implementations.values()) {
       cleaner.register(obj, implementation.port);
     }
@@ -103,30 +115,39 @@ public Object build() throws ClassNotFoundException {
   /// [0]: The address of the result pointer used for the clean-up.
   /// [1]: The result of the invocation.
   private static native Object[] _invoke(
-      long port,
-      long isolateId,
-      long functionPtr,
-      Object proxy,
-      String methodDescriptor,
-      Object[] args,
-      boolean isBlocking);
+    long port,
+    long isolateId,
+    long functionPtr,
+    Object proxy,
+    String methodDescriptor,
+    Object[] args,
+    boolean isBlocking);
 
   private static native void _cleanUp(long resultPtr);
 
   @Override
   public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+    if (method.equals(equals)) {
+      return proxy == args[0];
+    }
+    if (method.equals(hashCode)) {
+      return System.identityHashCode(proxy);
+    }
+    if (method.equals(toString)) {
+      return proxy.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(proxy));
+    }
     DartImplementation implementation = implementations.get(method.getDeclaringClass().getName());
     String descriptor = getDescriptor(method);
     boolean isBlocking = !asyncMethods.contains(descriptor);
     Object[] result =
-        _invoke(
-            implementation.port,
-            isolateId,
-            implementation.pointer,
-            proxy,
-            descriptor,
-            args,
-            isBlocking);
+      _invoke(
+        implementation.port,
+        isolateId,
+        implementation.pointer,
+        proxy,
+        descriptor,
+        args,
+        isBlocking);
     if (!isBlocking) {
       return null;
     }

diff --git a/pkgs/jnigen/test/simple_package_test/runtime_test_registrant.dart b/pkgs/jnigen/test/simple_package_test/runtime_test_registrant.dart
@@ -754,6 +754,16 @@ void registerTests(String groupName, TestRunnerCallback test) {
           }
         });
       }
+      test('Object methods work', () {
+        final runnable = MyRunnable.implement($MyRunnable(
+          run: () {},
+        ));
+        expect(runnable == runnable, true);
+        expect(runnable != runnable, false);
+        expect(runnable.hashCode, runnable.hashCode);
+        expect(runnable.toString(), runnable.toString());
+        runnable.release();
+      });
     }
     group('Dart exceptions are handled', () {
       for (final exception in [UnimplementedError(), 'Hello!']) {