feat: support native ES classes with lazy registration

Author: NathanWalker

test-app/app/src/main/assets/app/mainpage.js

@@ -42,6 +42,7 @@ require("./tests/testGC");
 require("./tests/testsMemoryManagement");
 require("./tests/testFieldGetSet");
 require("./tests/extendedClassesTests");
+require("./tests/testNativeESClasses");
 //require("./tests/extendClassNameTests"); // as tests now run with SBG, this test fails the whole build process
 require("./tests/testJniReferenceLeak");
 require("./tests/testNativeModules");

test-app/app/src/main/assets/app/tests/testNativeESClasses.js

@@ -0,0 +1,338 @@
+describe("Tests native ES class extensions (class X extends NativeType)", function () {
+
+    var appClassLoader = com.tns.Runtime.class.getClassLoader();
+
+    // DummyClass.method2(Object) returns "obj=" + obj.toString(), forcing a Java-side virtual
+    // toString dispatch through the generated proxy. (java.lang.String.valueOf is unusable for
+    // this: accessing `java.lang.String.null` in other suites permanently replaces `valueOf` on
+    // the ctor function with the runtime's null-returning valueOf.)
+    function javaToString(obj) {
+        return new com.tns.tests.DummyClass().method2(obj);
+    }
+
+    it("When_extending_a_class_with_es_class_syntax_instances_should_construct_and_dispatch_overrides", function () {
+        class EsButton extends com.tns.tests.Button1 {
+            getIMAGE_ID_PROP() {
+                return "es class override";
+            }
+        }
+
+        var button = new EsButton();
+
+        expect(button instanceof EsButton).toBe(true);
+        expect(button instanceof com.tns.tests.Button1).toBe(true);
+        expect(button.getIMAGE_ID_PROP()).toBe("es class override");
+        // non-overridden base methods still work
+        expect(button.echo("hello")).toBe("hello");
+    });
+
+    it("When_java_calls_a_virtual_method_it_should_dispatch_to_the_es_class_override", function () {
+        class EchoButton extends com.tns.tests.Button1 {
+            echo(s) {
+                return "es:" + s;
+            }
+        }
+
+        var button = new EchoButton();
+
+        // triggerEcho calls this.echo(s) on the Java side - it must route
+        // through the generated proxy back into the ES class method
+        expect(button.triggerEcho("x")).toBe("es:x");
+    });
+
+    it("When_calling_super_method_from_an_es_class_override_it_should_invoke_the_java_implementation", function () {
+        class SuperEchoButton extends com.tns.tests.Button1 {
+            echo(s) {
+                return "es:" + super.echo(s);
+            }
+        }
+
+        var button = new SuperEchoButton();
+
+        expect(button.echo("y")).toBe("es:y");
+        // round trip: Java triggerEcho -> proxy echo -> JS override -> super.echo -> Java echo
+        expect(button.triggerEcho("z")).toBe("es:z");
+    });
+
+    it("When_the_es_class_constructor_passes_arguments_to_super_the_matching_java_constructor_should_be_used", function () {
+        class CtorButton extends com.tns.tests.Button1 {
+            constructor(value) {
+                super(value); // Button1(int) overload
+                this.value = value;
+            }
+        }
+
+        var button = new CtorButton(5);
+
+        expect(button.value).toBe(5);
+        expect(button instanceof com.tns.tests.Button1).toBe(true);
+    });
+
+    it("When_accessing_the_class_property_before_any_instance_exists_the_class_should_be_registered_lazily", function () {
+        class LazyTouch extends java.lang.Object {
+            toString() {
+                return "lazy touch";
+            }
+        }
+
+        // no `new` has happened - static touch must register the proxy class
+        var clazz = LazyTouch.class;
+
+        expect(clazz).not.toBe(null);
+        expect(clazz.getName()).toContain("LazyTouch");
+
+        // the class is fully functional before any JS-side construction:
+        // Java instantiates it through reflection and dispatches to the JS override
+        var created = clazz.newInstance();
+        expect(javaToString(created)).toBe("obj=lazy touch");
+    });
+
+    it("When_passing_the_es_class_to_a_java_method_expecting_a_class_it_should_marshal_to_java_lang_Class", function () {
+        class MarshalledClass extends com.tns.tests.DummyClass {
+        }
+
+        // Class.isAssignableFrom(Class) - MarshalledClass is registered lazily during marshalling
+        expect(com.tns.tests.DummyClass.class.isAssignableFrom(MarshalledClass)).toBe(true);
+        expect(java.lang.Object.class.isAssignableFrom(MarshalledClass)).toBe(true);
+    });
+
+    it("When_passing_the_es_class_where_java_lang_Object_is_expected_it_should_marshal_to_its_java_lang_Class", function () {
+        class ObjectMarshalledClass extends java.lang.Object {
+        }
+
+        var list = new java.util.ArrayList();
+        list.add(ObjectMarshalledClass);
+
+        var stored = list.get(0);
+        expect(stored.getName()).toBe(ObjectMarshalledClass.class.getName());
+    });
+
+    it("When_extending_an_es_class_that_extends_a_native_class_each_level_should_get_its_own_proxy", function () {
+        class LevelOne extends com.tns.tests.Button1 {
+            getIMAGE_ID_PROP() {
+                return "level one";
+            }
+            echo(s) {
+                return "L1:" + s;
+            }
+        }
+
+        class LevelTwo extends LevelOne {
+            getIMAGE_ID_PROP() {
+                return "level two + " + super.getIMAGE_ID_PROP();
+            }
+        }
+
+        var two = new LevelTwo();
+        expect(two instanceof LevelTwo).toBe(true);
+        expect(two instanceof LevelOne).toBe(true);
+        expect(two instanceof com.tns.tests.Button1).toBe(true);
+        expect(two.getIMAGE_ID_PROP()).toBe("level two + level one");
+        // method defined only on the intermediate level must be part of the proxy overrides
+        expect(two.triggerEcho("q")).toBe("L1:q");
+
+        var one = new LevelOne();
+        expect(one.getIMAGE_ID_PROP()).toBe("level one");
+        expect(one instanceof LevelTwo).toBe(false);
+
+        expect(one.getClass().getName()).not.toBe(two.getClass().getName());
+    });
+
+    it("When_constructing_the_es_class_multiple_times_all_instances_should_share_one_proxy_class", function () {
+        class SharedProxyButton extends com.tns.tests.Button1 {
+        }
+
+        var first = new SharedProxyButton();
+        var second = new SharedProxyButton();
+
+        expect(first.getClass().equals(second.getClass())).toBe(true);
+        expect(first.getClass().equals(SharedProxyButton.class)).toBe(true);
+    });
+
+    it("When_reading_base_class_statics_through_the_es_class_they_should_resolve_to_the_java_members", function () {
+        class StaticsButton extends com.tns.tests.Button1 {
+            static jsStatic = 42;
+            static jsStaticMethod() {
+                return "js static";
+            }
+        }
+
+        // Java statics are reachable through the constructor prototype chain
+        expect(StaticsButton.STATIC_IMAGE_ID).toBe("static image id");
+        expect(StaticsButton.SGetStaticImageId()).toBe("static image id");
+
+        // plain JS statics live on the JS constructor and are untouched
+        expect(StaticsButton.jsStatic).toBe(42);
+        expect(StaticsButton.jsStaticMethod()).toBe("js static");
+    });
+
+    it("When_the_es_class_is_registered_its_proxy_should_be_discoverable_through_the_app_class_loader", function () {
+        class DiscoverableEsClass extends java.lang.Object {
+            toString() {
+                return "discoverable es class";
+            }
+        }
+
+        var instance = new DiscoverableEsClass();
+        var className = instance.getClass().getName();
+
+        var found = java.lang.Class.forName(className, false, appClassLoader);
+
+        expect(found.getName()).toBe(className);
+        expect(found.equals(instance.getClass())).toBe(true);
+        expect(found.equals(DiscoverableEsClass.class)).toBe(true);
+    });
+
+    it("When_implementing_an_interface_with_es_class_syntax_java_should_dispatch_to_the_js_methods", function () {
+        var runCount = 0;
+
+        class EsRunnable extends java.lang.Runnable {
+            run() {
+                runCount++;
+            }
+        }
+
+        var runnable = new EsRunnable();
+        expect(runnable instanceof java.lang.Runnable).toBe(true);
+
+        // Thread.run() (not started) invokes target.run() synchronously on the current thread
+        var thread = new java.lang.Thread(runnable);
+        thread.run();
+
+        expect(runCount).toBe(1);
+    });
+
+    it("When_declaring_static_interfaces_the_proxy_should_implement_them", function () {
+        var ran = { value: false };
+
+        class WithInterfaces extends java.lang.Object {
+            static interfaces = [java.lang.Runnable];
+
+            run() {
+                ran.value = true;
+            }
+        }
+
+        var instance = new WithInterfaces();
+
+        expect(instance instanceof java.lang.Runnable).toBe(true);
+
+        var thread = new java.lang.Thread(instance);
+        thread.run();
+
+        expect(ran.value).toBe(true);
+    });
+
+    it("When_getting_the_class_name_it_should_be_stable_and_descriptive", function () {
+        class StableNameClass extends java.lang.Object {
+        }
+
+        var name = StableNameClass.class.getName();
+
+        // runtime generated proxies are named <base>_es<hash>_<jsClassName>, mirroring the
+        // legacy <base>_<file>_<line>_<column>_<name> scheme (the com.tns.gen prefix is only
+        // present on build-time pre-generated bindings)
+        expect(name).toContain("java.lang.Object_es");
+        expect(name).toContain("StableNameClass");
+        // repeated access resolves to the very same class
+        expect(StableNameClass.class.getName()).toBe(name);
+    });
+
+    it("When_passing_an_es_class_instance_to_java_and_reading_it_back_it_should_be_the_same_object", function () {
+        class RoundTripObject extends java.lang.Object {
+            toString() {
+                return "round trip";
+            }
+        }
+
+        var instance = new RoundTripObject();
+        var list = new java.util.ArrayList();
+        list.add(instance);
+
+        var stored = list.get(0);
+        expect(stored.equals(instance)).toBe(true);
+        expect(javaToString(stored)).toBe("obj=round trip");
+    });
+
+    it("When_calling_extend_on_an_es_class_it_should_throw_a_descriptive_error", function () {
+        class NotExtendable extends com.tns.tests.Button1 {
+        }
+
+        expect(function () {
+            NotExtendable.extend({
+                toString: function () {
+                    return "should not work";
+                }
+            });
+        }).toThrow();
+    });
+
+    it("When_extending_a_class_created_with_legacy_extend_the_old_behavior_should_be_preserved", function () {
+        var LegacyButton = com.tns.tests.Button1.extend({
+            getIMAGE_ID_PROP: function () {
+                return "legacy override";
+            }
+        });
+
+        class EsOnLegacy extends LegacyButton {
+        }
+
+        // the legacy proxy is used - ES levels above `.extend()`-created classes get no proxy of their own
+        var instance = new EsOnLegacy();
+        expect(instance instanceof com.tns.tests.Button1).toBe(true);
+        expect(instance.getIMAGE_ID_PROP()).toBe("legacy override");
+    });
+
+    it("When_a_plain_js_class_hierarchy_is_used_the_runtime_should_not_interfere", function () {
+        class PlainBase {
+            value() {
+                return 1;
+            }
+        }
+
+        class PlainDerived extends PlainBase {
+            value() {
+                return super.value() + 1;
+            }
+        }
+
+        var plain = new PlainDerived();
+        expect(plain.value()).toBe(2);
+        expect(function () {
+            return plain instanceof java.lang.Object;
+        }).not.toThrow();
+    });
+
+    it("When_the_NativeClass_decorator_is_applied_it_should_be_a_noop", function () {
+        expect(typeof global.NativeClass).toBe("function");
+
+        const DecoratedButton = global.NativeClass(class DecoratedButton extends com.tns.tests.Button1 {
+            getIMAGE_ID_PROP() {
+                return "decorated";
+            }
+        });
+
+        var button = new DecoratedButton();
+        expect(button.getIMAGE_ID_PROP()).toBe("decorated");
+    });
+
+    it("When_anonymous_es_classes_extend_native_types_each_should_get_a_distinct_proxy", function () {
+        var First = class extends java.lang.Object {
+            toString() {
+                return "first anonymous";
+            }
+        };
+        var Second = class extends java.lang.Object {
+            toString() {
+                return "second anonymous";
+            }
+        };
+
+        var firstInstance = new First();
+        var secondInstance = new Second();
+
+        expect(javaToString(firstInstance)).toBe("obj=first anonymous");
+        expect(javaToString(secondInstance)).toBe("obj=second anonymous");
+        expect(firstInstance.getClass().equals(secondInstance.getClass())).toBe(false);
+    });
+});

test-app/app/src/main/assets/internal/ts_helpers.js

@@ -166,6 +166,14 @@
 		}
 	}
 
+	// No-op decorator for plain ES classes extending native types.
+	// The runtime registers such classes lazily (on first construction, static usage or when
+	// passed to native APIs), so the decorator only exists so shared iOS/Android sources and
+	// non-transformed code keep working.
+	function NativeClass(target) {
+		return target;
+	}
+
 	Object.defineProperty(global, "__native", { value: __native });
 	Object.defineProperty(global, "__extends", { value: __extends });
 	Object.defineProperty(global, "__decorate", { value: __decorate });
@@ -174,4 +182,7 @@
 		global.JavaProxy = JavaProxy;
 	}
 	global.Interfaces = Interfaces;
+	if (!global.NativeClass) {
+		global.NativeClass = NativeClass;
+	}
 })()