dartium_js_interop changes

sdk/lib/js/dartium/js_dartium.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.
 
-/**
- * The js.dart library provides simple JavaScript invocation from Dart that
- * works on both Dartium and on other modern browsers via Dart2JS.
- *
- * It provides a model based on scoped [JsObject] objects.  Proxies give Dart
- * code access to JavaScript objects, fields, and functions as well as the
- * ability to pass Dart objects and functions to JavaScript functions.  Scopes
- * enable developers to use proxies without memory leaks - a common challenge
- * with cross-runtime interoperation.
- *
- * The top-level [context] getter provides a [JsObject] to the global JavaScript
- * context for the page your Dart code is running on.  In the following example:
- *
- *     import 'dart:js';
- *
- *     void main() {
- *       context.callMethod('alert', ['Hello from Dart via JavaScript']);
- *     }
- *
- * context['alert'] creates a proxy to the top-level alert function in
- * JavaScript.  It is invoked from Dart as a regular function that forwards to
- * the underlying JavaScript one.  By default, proxies are released when
- * the currently executing event completes, e.g., when main is completes
- * in this example.
- *
- * The library also enables JavaScript proxies to Dart objects and functions.
- * For example, the following Dart code:
- *
- *     context['dartCallback'] = new Callback.once((x) => print(x*2));
- *
- * defines a top-level JavaScript function 'dartCallback' that is a proxy to
- * the corresponding Dart function.  The [Callback.once] constructor allows the
- * proxy to the Dart function to be retained across multiple events;
- * instead it is released after the first invocation.  (This is a common
- * pattern for asychronous callbacks.)
- *
- * Note, parameters and return values are intuitively passed by value for
- * primitives and by reference for non-primitives.  In the latter case, the
- * references are automatically wrapped and unwrapped as proxies by the library.
- *
- * This library also allows construction of JavaScripts objects given a
- * [JsObject] to a corresponding JavaScript constructor.  For example, if the
- * following JavaScript is loaded on the page:
- *
- *     function Foo(x) {
- *       this.x = x;
- *     }
- *
- *     Foo.prototype.add = function(other) {
- *       return new Foo(this.x + other.x);
- *     }
- *
- * then, the following Dart:
- *
- *     var foo = new JsObject(context['Foo'], [42]);
- *     var foo2 = foo.callMethod('add', [foo]);
- *     print(foo2['x']);
- *
- * will construct a JavaScript Foo object with the parameter 42, invoke its
- * add method, and return a [JsObject] to a new Foo object whose x field is 84.
- */
+library dart.Js;

[Jennifer Messerly, 2013/10/11 19:21:09]

did you mean to uppercase the "J"?

[Jacob, 2013/10/15 22:39:44]

Done.
lowercased.

 
-library dart.js;
+import 'dart:nativewrappers';
 
-import 'dart:html';
-import 'dart:isolate';
-
-// Global ports to manage communication from Dart to JS.
-SendPortSync _jsPortSync = window.lookupPort('dart-js-context');
-SendPortSync _jsPortCreate = window.lookupPort('dart-js-create');
-SendPortSync _jsPortInstanceof = window.lookupPort('dart-js-instanceof');
-SendPortSync _jsPortDeleteProperty = window.lookupPort('dart-js-delete-property');
-SendPortSync _jsPortConvert = window.lookupPort('dart-js-convert');
-
-
-JsObject _context;
-
-/**
- * Returns a proxy to the global JavaScript context for this page.
- */
-JsObject get context {
-  if (_context == null) {
-    var port = _jsPortSync;
-    if (port == null) {
-      return null;
-    }
-    _context = _deserialize(_jsPortSync.callSync([]));
-  }
-  return _context;
-}
-
+JsObject get context native "Js_context_Callback";
+  
 /**
  * Converts a json-like [data] to a JavaScript map or array and return a
  * [JsObject] to it.
  */
-JsObject jsify(dynamic data) => data == null ? null : new JsObject._json(data);
+JsObject jsify(dynamic data) native "Js_jsify";

[justinfagnani, 2013/10/11 18:30:59]

I think we should move this to a constructor on JsObject that has a name to
indicate the deep-conversion behavior

[Jacob, 2013/10/15 22:39:44]

Done. Although we still need a clearer name.

 
 /**
- * Converts a local Dart function to a callback that can be passed to
- * JavaScript.
+ * Returns a [JsFunction] that captures its 'this' binding and calls [f]
+ * with the value of this passed as the first argument.
  */
-class Callback implements Serializable<JsFunction> {
-  JsFunction _f;
+JsFunction captureThis(Function f) native "Js_captureThis";
 
-  Callback._(Function f, bool withThis) {
-    final id = _proxiedObjectTable.add((List args) {
-      final arguments = new List.from(args);
-      if (!withThis) arguments.removeAt(0);
-      return Function.apply(f, arguments);
-    });
-    _f = new JsFunction._internal(_proxiedObjectTable.sendPort, id);
+class JsObject extends NativeFieldWrapperClass1 {

[justinfagnani, 2013/10/11 18:30:59]

will NativeFieldWrapperClass1 be visible in the objects superclass chain? How
can we make this and the dart2js JsObject be the same? Should JsObject just be
an interface?

[Jacob, 2013/10/15 22:39:44]

Discussed offline.
I wouldn't worry too much about the extends NativeFieldWrapperClass1
All classes in dart:html suffer from the same wart and so far it hasn't been an
issue as far as I know. That class doesn't have any public methods and cannot be
imported when using dart2js.

+
+  factory JsObject(JsFunction constructor, [List arguments]) => _create(constructor, arguments);
+
+  static JsObject _create(JsFunction constructor, arguments) native "JsObject_constructorCallback";
+
+   /**
+    * Expert users only:
+    * Use this constructor only if you wish to get access to JS expandos
+    * attached to a WebKit native object such as a Node.
+    * An exception will be thrown if a primitive type is passed in passing one
+    * of these types to this method indicates an error.
+    */
+  factory JsObject.fromDartObject(var object) {

[vsm, 2013/10/15 21:05:34]

Perhaps fromBrowserObject?  Will this throw if object isn't a native type? 
Maybe check that object is NativeFieldWrapper*?

[Jacob, 2013/10/15 22:39:44]

one step ahead of me. :) just wrote a comment that we will do exactly that. I
also prefer the name fromBrowserObject. I disliked the existing name.

+    if (object is num || object is String || object == null) {

[justinfagnani, 2013/10/11 18:30:59]

add bool

[Jacob, 2013/10/15 22:39:44]

synced offline.  Instead restricting further and throwing if object isn't one of
the small list of types that we perform auto-conversions on. Those are the only
types where this method makes any sense.

[Jacob, 2013/10/15 22:39:44]

Synced offline. We'll restrict which types can be passed to this method further.
Only types where we can get a true JS peer will be allowed. All others will
throw.  This means only the subset of browser native types that we allow
auto-conversion for. 

+       throw new IllegalArgumentException("object cannot be a num, string, or null");

[justinfagnani, 2013/10/11 18:30:59]

what about returning a proxy to the boxed primitive?

[Jacob, 2013/10/15 22:39:44]

same note as previous comment.

+    }
+    return _fromDartObject(object);
   }
 
-  factory Callback(Function f) => new Callback._(f, false);
-  factory Callback.withThis(Function f) => new Callback._(f, true);
+  static JsObject _fromDartObject(object) native "JsObject_fromDartObject";
 
-  JsFunction toJs() => _f;
-}
+  operator[](key) native "JsObject_[]";
+  operator[]=(key, value) native "JsObject_[]=";
 
-/**
- * Proxies to JavaScript objects.
- */
-class JsObject implements Serializable<JsObject> {
-  final SendPortSync _port;
-  final String _id;
+  int get hashCode => 0;

[justinfagnani, 2013/10/11 18:30:59]

we talked about an identity-based hashCode

[Jacob, 2013/10/15 22:39:44]

added that to this cl.

 
-  /**
-   * Constructs a [JsObject] to a new JavaScript object by invoking a (proxy to
-   * a) JavaScript [constructor].  The [arguments] list should contain either
-   * primitive values, DOM elements, or Proxies.
-   */
-  factory JsObject(Serializable<JsFunction> constructor, [List arguments]) {
-    final params = [constructor];
-    if (arguments != null) params.addAll(arguments);
-    final serialized = params.map(_serialize).toList();
-    final result = _jsPortCreate.callSync(serialized);
-    return _deserialize(result);
-  }
+  operator==(other) => other is JsObject && _identityEquality(this, other);
 
-  /**
-   * Constructs a [JsObject] to a new JavaScript map or list created defined via
-   * Dart map or list.
-   */
-  factory JsObject._json(data) => _convert(data);
+  static bool _identityEquality(JsObject a, JsObject b) native "JsObject_identityEquality";
 
-  static _convert(data) =>
-      _deserialize(_jsPortConvert.callSync(_serializeDataTree(data)));
+  bool hasProperty(String property) native "JsObject_hasProperty";
 
-  static _serializeDataTree(data) {
-    if (data is Map) {
-      final entries = new List();
-      for (var key in data.keys) {
-        entries.add([key, _serializeDataTree(data[key])]);
-      }
-      return ['map', entries];
-    } else if (data is Iterable) {
-      return ['list', data.map(_serializeDataTree).toList()];
-    } else {
-      return ['simple', _serialize(data)];
-    }
-  }
+  void deleteProperty(JsFunction name) native "JsObject_deleteProperty";
 
-  JsObject._internal(this._port, this._id);
-
-  JsObject toJs() => this;
-
-  // Resolve whether this is needed.
-  operator[](arg) => _forward(this, '[]', 'method', [ arg ]);
-
-  // Resolve whether this is needed.
-  operator[]=(key, value) => _forward(this, '[]=', 'method', [ key, value ]);
-
-  int get hashCode => _id.hashCode;
-
-  // Test if this is equivalent to another Proxy.  This essentially
-  // maps to JavaScript's === operator.
-  operator==(other) => other is JsObject && this._id == other._id;
-
-  /**
-   * Check if this [JsObject] has a [name] property.
-   */
-  bool hasProperty(String name) => _forward(this, name, 'hasProperty', []);
-
-  /**
-   * Delete the [name] property.
-   */
-  void deleteProperty(String name) {
-    _jsPortDeleteProperty.callSync([this, name].map(_serialize).toList());
-  }
-
-  /**
-   * Check if this [JsObject] is instance of [type].
-   */
-  bool instanceof(Serializable<JsFunction> type) =>
-      _jsPortInstanceof.callSync([this, type].map(_serialize).toList());
+  bool instanceof(JsFunction type) native "JsObject_instanceof";
 
   String toString() {
     try {
-      return _forward(this, 'toString', 'method', []);
+      return _toString();
     } catch(e) {
       return super.toString();
     }
   }
 
-  callMethod(String name, [List args]) {
-    return _forward(this, name, 'method', args != null ? args : []);
-  }
+  // FIXME: should we remove this? It seems like a a JS mis-feature we
+  // shouldn't be exposing. If someone really wants it they can expose
+  // it themselves. If you have a JsObject then the value of jsType
+  // is unlikely to be interesting as it should just be "object" or
+  // "function" unless you used the pro-user only forceToJs method.
+  // String get jsType native "JsObject_jsType";

[justinfagnani, 2013/10/11 18:30:59]

yes, remove it, it's not in current dart:js anyway

[Jacob, 2013/10/15 22:39:44]

yay :) done.

 
-  // Forward member accesses to the backing JavaScript object.
-  static _forward(JsObject receiver, String member, String kind, List args) {
-    var result = receiver._port.callSync([receiver._id, member, kind,
-                                          args.map(_serialize).toList()]);
-    switch (result[0]) {
-      case 'return': return _deserialize(result[1]);
-      case 'throws': throw _deserialize(result[1]);
-      case 'none':
-          throw new NoSuchMethodError(receiver, new Symbol(member), args, {});
-      default: throw 'Invalid return value';
-    }
-  }
+  String _toString() native "JsObject_toString";
+
+  callMethod(String name, [List args]) native "JsObject_callMethod";
 }
 
-/// A [JsObject] subtype to JavaScript functions.
-class JsFunction extends JsObject implements Serializable<JsFunction> {
-  JsFunction._internal(SendPortSync port, String id)
-      : super._internal(port, id);
-
-  apply(thisArg, [List args]) {
-    return JsObject._forward(this, '', 'apply',
-        [thisArg]..addAll(args == null ? [] : args));
-  }
+class JsFunction extends JsObject {
+  apply(thisArg, [List args]) native "JsFunction_apply";

[justinfagnani, 2013/10/11 18:30:59]

I think we should make thisArg optional

 }
-
-/// Marker class used to indicate it is serializable to js. If a class is a
-/// [Serializable] the "toJs" method will be called and the result will be used
-/// as value.
-abstract class Serializable<T> {
-  T toJs();
-}
-
-// A table to managed local Dart objects that are proxied in JavaScript.
-class _ProxiedObjectTable {
-  // Debugging name.
-  final String _name;
-
-  // Generator for unique IDs.
-  int _nextId;
-
-  // Table of IDs to Dart objects.
-  final Map<String, Object> _registry;
-
-  // Port to handle and forward requests to the underlying Dart objects.
-  // A remote proxy is uniquely identified by an ID and SendPortSync.
-  final ReceivePortSync _port;
-
-  _ProxiedObjectTable() :
-      _name = 'dart-ref',
-      _nextId = 0,
-      _registry = {},
-      _port = new ReceivePortSync() {
-    _port.receive((msg) {
-      try {
-        final receiver = _registry[msg[0]];
-        final method = msg[1];
-        final args = msg[2].map(_deserialize).toList();
-        if (method == '#call') {
-          final func = receiver as Function;
-          var result = _serialize(func(args));
-          return ['return', result];
-        } else {
-          // TODO(vsm): Support a mechanism to register a handler here.
-          throw 'Invocation unsupported on non-function Dart proxies';
-        }
-      } catch (e) {
-        // TODO(vsm): callSync should just handle exceptions itself.
-        return ['throws', '$e'];
-      }
-    });
-  }
-
-  // Adds a new object to the table and return a new ID for it.
-  String add(x) {
-    // TODO(vsm): Cache x and reuse id.
-    final id = '$_name-${_nextId++}';
-    _registry[id] = x;
-    return id;
-  }
-
-  // Gets an object by ID.
-  Object get(String id) {
-    return _registry[id];
-  }
-
-  // Gets the current number of objects kept alive by this table.
-  get count => _registry.length;
-
-  // Gets a send port for this table.
-  get sendPort => _port.toSendPort();
-}
-
-// The singleton to manage proxied Dart objects.
-_ProxiedObjectTable _proxiedObjectTable = new _ProxiedObjectTable();
-
-/// End of proxy implementation.
-
-// Dart serialization support.
-
-_serialize(var message) {
-  if (message == null) {
-    return null;  // Convert undefined to null.
-  } else if (message is String ||
-             message is num ||
-             message is bool) {
-    // Primitives are passed directly through.
-    return message;
-  } else if (message is SendPortSync) {
-    // Non-proxied objects are serialized.
-    return message;
-  } else if (message is JsFunction) {
-    // Remote function proxy.
-    return [ 'funcref', message._id, message._port ];
-  } else if (message is JsObject) {
-    // Remote object proxy.
-    return [ 'objref', message._id, message._port ];
-  } else if (message is Serializable) {
-    // use of result of toJs()
-    return _serialize(message.toJs());
-  } else if (message is Function) {
-    return _serialize(new Callback(message));
-  } else {
-    // Local object proxy.
-    return [ 'objref',
-             _proxiedObjectTable.add(message),
-             _proxiedObjectTable.sendPort ];
-  }
-}
-
-_deserialize(var message) {
-  deserializeFunction(message) {
-    var id = message[1];
-    var port = message[2];
-    if (port == _proxiedObjectTable.sendPort) {
-      // Local function.
-      return _proxiedObjectTable.get(id);
-    } else {
-      // Remote function.  Forward to its port.
-      return new JsFunction._internal(port, id);
-    }
-  }
-
-  deserializeObject(message) {
-    var id = message[1];
-    var port = message[2];
-    if (port == _proxiedObjectTable.sendPort) {
-      // Local object.
-      return _proxiedObjectTable.get(id);
-    } else {
-      // Remote object.
-      return new JsObject._internal(port, id);
-    }
-  }
-
-  if (message == null) {
-    return null;  // Convert undefined to null.
-  } else if (message is String ||
-             message is num ||
-             message is bool) {
-    // Primitives are passed directly through.
-    return message;
-  } else if (message is SendPortSync) {
-    // Serialized type.
-    return message;
-  }
-  var tag = message[0];
-  switch (tag) {
-    case 'funcref': return deserializeFunction(message);
-    case 'objref': return deserializeObject(message);
-  }
-  throw 'Unsupported serialized data: $message';
-}