Support for dart:typed_data

tool/input_sdk/private/classes.dart

 // Copyright (c) 2015, 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.
 
 /// This library defines the operations that define and manipulate Dart
 /// classes.  Included in this are:
 ///   - Generics
 ///   - Class metadata
 ///   - Extension methods
 ///
@@ skipping 241 matching lines @@
   let initMethod = proto[$name];
   let ctor = function() { return initMethod.apply(this, arguments); };
   ctor.prototype = proto;
   // Use defineProperty so we don't hit a property defined on Function,
   // like `caller` and `arguments`.
   $defineProperty($clazz, $name, { value: ctor, configurable: true });
 })()''');
 
 final _extensionType = JS('', 'Symbol("extensionType")');
 
+getExtensionType(obj) => JS('', '$obj[$_extensionType]');
+
 final dartx = JS('', '{}');
 
 getExtensionSymbol(name) => JS('', '''(() => {
   let sym = $dartx[$name];
   if (!sym) $dartx[$name] = sym = Symbol('dartx.' + $name);
   return sym;
 })()''');
 
 defineExtensionNames(names) => JS('', '$names.forEach($getExtensionSymbol)');
 
+// Install properties in prototype order.  Properties / descriptors from
+// more specific types should overwrite ones from less specific types.
+_installProperties(jsProto, extProto) => JS('', '''(() => {
+  if (extProto !== $Object.prototype && extProto !== jsProto) {
+    $_installProperties(jsProto, extProto.__proto__);
+  }
+  $copyTheseProperties(jsProto, extProto, $getOwnPropertySymbols(extProto));
+})()''');
+
 ///
 /// Copy symbols from the prototype of the source to destination.
 /// These are the only properties safe to copy onto an existing public
 /// JavaScript class.
 ///
 registerExtension(jsType, dartExtType) => JS('', '''(() => {
   let extProto = $dartExtType.prototype;
   let jsProto = $jsType.prototype;
 
   // Mark the JS type's instances so we can easily check for extensions.
   $assert_(jsProto[$_extensionType] === void 0);
-  jsProto[$_extensionType] = extProto;
-
-  let dartObjProto = $Object.prototype;
-  while (extProto !== dartObjProto && extProto !== jsProto) {
-    $copyTheseProperties(jsProto, extProto, $getOwnPropertySymbols(extProto));
-    extProto = extProto.__proto__;
-  }
+  jsProto[$_extensionType] = $dartExtType;
+  $_installProperties(jsProto, extProto);
   let originalSigFn = $getOwnPropertyDescriptor($dartExtType, $_methodSig).get;
   $assert_(originalSigFn);
   $defineMemoizedGetter($jsType, $_methodSig, originalSigFn);
 })()''');
 
 ///
 /// Mark a concrete type as implementing extension methods.
 /// For example: `class MyIter implements Iterable`.
 ///
 /// This takes a list of names, which are the extension methods implemented.
@@ skipping 38 matching lines @@
   // Check for certain names that we can't use in JS
   if ($name == 'constructor' || $name == 'prototype') {
     $name = '+' + $name;
   }
   return $name;
 })()''');
 
 /// Sets the type of `obj` to be `type`
 setType(obj, type) => JS('', '''(() => {
   $obj.__proto__ = $type.prototype;
+  // TODO(vsm): This should be set in registerExtension, but that is only
+  // invoked on the generic type (e.g., JSArray<dynamic>, not JSArray<int>).
+  $obj.__proto__[$_extensionType] = $type;
   return $obj;
 })()''');
 
 /// Sets the element type of a list literal.
 list(obj, elementType) =>
     JS('', '$setType($obj, ${getGenericClass(JSArray)}($elementType))');
 
 setBaseClass(derived, base) => JS('', '''(() => {
   // Link the extension to the type it's extending as a base class.
   $derived.prototype.__proto__ = $base.prototype;
 })()''');