Generative constructor factories for native objects

tests/compiler/dart2js_native/subclassing_constructor_1_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import "package:expect/expect.dart";
+import 'dart:_foreign_helper' show JS;
+import 'dart:_js_helper' show Creates, setNativeSubclassDispatchRecord;
+import 'dart:_interceptors' show
+    findInterceptorForType, findConstructorForWebComponentType;
+
+// Test that subclasses of native classes can be initialized by calling the
+// 'upgrade' constructor.
+
+var trace = [];
+
+var log;
+
+class A native "A" {
+  final a1 = log(101);  // Only initialized IF named constructor called.
+  final a2;             // Initialized by native constructor.
+  final a3;             // Initialized only by A.two.
+  var a4 = log(104);
+
+  A.one();
+
+  A.two() : a3 = log(103) {
+    log('body(A.two)');
+    log(a4 += increment);
+  }
+
+  A.three(x, this.a4) {
+    log('body(A.three)');
+    log(a4 = '($a4, $x)');
+  }
+
+  get increment => 10;
+}
+
+class B extends A {
+  final b1;
+  final b2 = log(202);
+  var b3;
+
+  B.one() : super.one();
+
+  B.two() : b1 = log(201), super.two(), b3 = log(203) {
+    log('body(B.two)');
+  }
+
+  B.three([x]) : super.three(205, x);
+
+  get increment => 20;
+}
+
+
+makeB() native;
+
+@Creates('=Object')
+getBPrototype() native;
+
+void setup() native r"""
+function B() { this.a2 = 102; }
+
+makeB = function(){return new B;};
+
+getBPrototype = function(){return B.prototype;};
+""";
+
+
+test_one() {
+  trace = [];
+  var constructor = findConstructorForWebComponentType(B, 'one');
+  Expect.isNotNull(constructor);
+  Expect.isNull(findConstructorForWebComponentType(B, 'Missing'));
+
+  var b = makeB();
+  Expect.isTrue(b is B);
+  // Call constructor to initialize native object.
+  var b2 = JS('', '#(#)', constructor, b);
+  Expect.identical(b, b2);
+  Expect.isTrue(b is B);
+
+  Expect.equals(101, b.a1);
+  Expect.equals(102, b.a2);
+  Expect.equals(null, b.a3);
+  Expect.equals(104, b.a4);
+  Expect.equals(null, b.b1);
+  Expect.equals(202, b.b2);
+  Expect.equals(null, b.b3);
+
+  Expect.equals('[202, 101, 104]', '$trace');
+}
+
+test_two() {
+  trace = [];
+  var constructor = findConstructorForWebComponentType(B, 'two');
+  Expect.isNotNull(constructor);
+
+  var b = makeB();
+  Expect.isTrue(b is B);
+  // Call constructor to initialize native object.
+  JS('', '#(#)', constructor, b);
+  Expect.isTrue(b is B);
+
+  Expect.equals(101, b.a1);
+  Expect.equals(102, b.a2);
+  Expect.equals(103, b.a3);
+  Expect.equals(124, b.a4);
+  Expect.equals(201, b.b1);
+  Expect.equals(202, b.b2);
+  Expect.equals(203, b.b3);
+
+  Expect.equals(
+      '[202, 201, 101, 104, 103, 203, body(A.two), 124, body(B.two)]',
+      '$trace');
+}
+
+test_three() {
+  trace = [];
+  var constructor = findConstructorForWebComponentType(B, 'three');
+  Expect.isNotNull(constructor);
+
+  var b = makeB();
+  Expect.isTrue(b is B);
+  // Call constructor to initialize native object.
+  //
+  // Since the constructor takes some optional arguments that are not passed, it
+  // is as though the web components runtime explicitly passed `null` for all
+  // parameters.
+  //
+  // TODO(sra): The constructor returned by findConstructorForWebComponentType
+  // should be a function that fills in the default values.
+  JS('', '#(#)', constructor, b);
+  Expect.isTrue(b is B);
+
+  Expect.equals(101, b.a1);
+  Expect.equals(102, b.a2);
+  Expect.equals(null, b.a3);
+  Expect.equals('(null, 205)', b.a4);
+  Expect.equals(null, b.b1);
+  Expect.equals(202, b.b2);
+  Expect.equals(null, b.b3);
+  print(trace);
+  Expect.equals('[202, 101, 104, body(A.three), (null, 205)]', '$trace');
+}
+
+test_new() {
+  trace = [];
+  checkThrows(action, description) {
+    Expect.throws(action, (e) => true, "'$description must fail'");
+  }
+
+  checkThrows(() => new B.one(), 'new B.one()');
+  checkThrows(() => new B.two(), 'new B.two()');
+  checkThrows(() => new B.three(), 'new B.three()');
+  checkThrows(() => new B.three(1), 'new B.three(1)');
+  checkThrows(() => new B.three([]), 'new B.three([])');
+}
+
+var inscrutable;
+
+main() {
+  setup();
+  inscrutable = (x) => x;
+  log = (message) {
+    trace.add('$message');
+    return message;
+  };
+
+  setNativeSubclassDispatchRecord(getBPrototype(), findInterceptorForType(B));
+
+  test_one();
+  test_two();
+  test_three();
+  test_new();
+}