Support user generated custom native JS classes.

sdk/lib/js/dart2js/js_dart2js.dart

Index: sdk/lib/js/dart2js/js_dart2js.dart
diff --git a/sdk/lib/js/dart2js/js_dart2js.dart b/sdk/lib/js/dart2js/js_dart2js.dart
index 849de82658db6c3982128d4d6d593c3fc165b4fb..402ebb6faa5e0fd5f450e3d5bfa5f07b95d65473 100644
--- a/sdk/lib/js/dart2js/js_dart2js.dart
+++ b/sdk/lib/js/dart2js/js_dart2js.dart
@@ -92,21 +92,28 @@ import 'dart:collection' show HashMap, ListMixin;
 import 'dart:indexed_db' show KeyRange;
 import 'dart:typed_data' show TypedData;
 
-import 'dart:_foreign_helper' show JS, DART_CLOSURE_TO_JS;
-import 'dart:_interceptors' show JavaScriptObject, UnknownJavaScriptObject;
-import 'dart:_js_helper' show Primitives, convertDartClosureToJS,
-    getIsolateAffinityTag;
+import 'dart:_foreign_helper' show JS, JS_CONST, DART_CLOSURE_TO_JS;
+import 'dart:_interceptors'
+    show JavaScriptObject, UnknownJavaScriptObject, DART_CLOSURE_PROPERTY_NAME;
+import 'dart:_js_helper'
+    show Primitives, convertDartClosureToJS, getIsolateAffinityTag;
+
+export 'dart:_interceptors' show Interceptor, JavaScriptObject, JSArray;
 
 final JsObject context = _wrapToDart(JS('', 'self'));
 
 _convertDartFunction(Function f, {bool captureThis: false}) {
-  return JS('',
-    'function(_call, f, captureThis) {'
+  return JS(
+      '',
+      'function(_call, f, captureThis) {'

[Siggi Cherem (dart-lang), 2015/09/18 20:34:10]

+1 on using ''' to restore indentation

[Jacob, 2015/10/01 00:47:33]

this file is now automatically formatted so please send your whitespace style
complaints to Bob :)

[sra1, 2015/10/01 17:34:30]

When this was originally written JS didn't parse functions so the indented
strings reduced space in the output.

Now we parse the whole thing, so use whitespace liberally to make it look nice.

[Siggi Cherem (dart-lang), 2015/10/01 18:21:28]

to clarify, what I meant was to use the triple-' going forward, which dartfmt
leaves alone :)

[Jacob, 2015/10/02 20:08:15]

fine. I switched to ''' and did a bunch of white space deck chair moving.

       'return function() {'
-        'return _call(f, captureThis, this, '
-            'Array.prototype.slice.apply(arguments));'
+      'return _call(f, captureThis, this, '
+      'Array.prototype.slice.apply(arguments));'
       '}'
-    '}(#, #, #)', DART_CLOSURE_TO_JS(_callDartFunction), f, captureThis);
+      '}(#, #, #)',
+      DART_CLOSURE_TO_JS(_callDartFunction),
+      f,
+      captureThis);
 }
 
 _callDartFunction(callback, bool captureThis, self, List arguments) {
@@ -212,8 +219,7 @@ class JsObject {
    */
   factory JsObject.fromBrowserObject(object) {
     if (object is num || object is String || object is bool || object == null) {
-      throw new ArgumentError(
-        "object cannot be a num, string, bool, or null");
+      throw new ArgumentError("object cannot be a num, string, bool, or null");
     }
     return _wrapToDart(_convertToJS(object));
   }
@@ -267,7 +273,7 @@ class JsObject {
    *
    * The type of [property] must be either [String] or [num].
    */
-  dynamic operator[](property) {
+  dynamic operator [](property) {
     if (property is! String && property is! num) {
       throw new ArgumentError("property is not a String or num");
     }
@@ -280,7 +286,7 @@ class JsObject {
    *
    * The type of [property] must be either [String] or [num].
    */
-  operator[]=(property, value) {
+  operator []=(property, value) {
     if (property is! String && property is! num) {
       throw new ArgumentError("property is not a String or num");
     }
@@ -289,8 +295,8 @@ class JsObject {
 
   int get hashCode => 0;
 
-  bool operator==(other) => other is JsObject &&
-      JS('bool', '# === #', _jsObject, other._jsObject);
+  bool operator ==(other) =>
+      other is JsObject && JS('bool', '# === #', _jsObject, other._jsObject);
 
   /**
    * Returns `true` if the JavaScript object contains the specified property
@@ -332,7 +338,7 @@ class JsObject {
   String toString() {
     try {
       return JS('String', 'String(#)', _jsObject);
-    } catch(e) {
+    } catch (e) {
       return super.toString();
     }
   }
@@ -347,7 +353,11 @@ class JsObject {
     if (method is! String && method is! num) {
       throw new ArgumentError("method is not a String or num");
     }
-    return _convertToDart(JS('', '#[#].apply(#, #)', _jsObject, method,
+    return _convertToDart(JS(
+        '',
+        '#[#].apply(#, #)',
+        _jsObject,
+        method,
         _jsObject,
         args == null ? null : new List.from(args.map(_convertToJS))));
   }
@@ -357,7 +367,6 @@ class JsObject {
  * Proxies a JavaScript Function object.
  */
 class JsFunction extends JsObject {
-
   /**
    * Returns a [JsFunction] that captures its 'this' binding and calls [f]
    * with the value of this passed as the first argument.
@@ -373,17 +382,18 @@ class JsFunction extends JsObject {
    * Invokes the JavaScript function with arguments [args]. If [thisArg] is
    * supplied it is the value of `this` for the invocation.
    */
-  dynamic apply(List args, { thisArg }) =>
-      _convertToDart(JS('', '#.apply(#, #)', _jsObject,
-          _convertToJS(thisArg),
-          args == null ? null : new List.from(args.map(_convertToJS))));
+  dynamic apply(List args, {thisArg}) => _convertToDart(JS(
+      '',
+      '#.apply(#, #)',
+      _jsObject,
+      _convertToJS(thisArg),
+      args == null ? null : new List.from(args.map(_convertToJS))));
 }
 
 /**
  * A [List] that proxies a JavaScript array.
  */
 class JsArray<E> extends JsObject with ListMixin<E> {
-
   /**
    * Creates a new JavaScript array.
    */
@@ -449,8 +459,9 @@ class JsArray<E> extends JsObject with ListMixin<E> {
     throw new StateError('Bad JsArray length');
   }
 
-  void set length(int length) { super['length'] = length; }
-
+  void set length(int length) {
+    super['length'] = length;
+  }
 
   // Methods overriden for better performance
 
@@ -503,12 +514,11 @@ class JsArray<E> extends JsObject with ListMixin<E> {
 // property added to a Dart object referencing its JS-side DartObject proxy
 final String _DART_OBJECT_PROPERTY_NAME =
     getIsolateAffinityTag(r'_$dart_dartObject');
-final String _DART_CLOSURE_PROPERTY_NAME =
-    getIsolateAffinityTag(r'_$dart_dartClosure');
 
 // property added to a JS object referencing its Dart-side JsObject proxy
 const _JS_OBJECT_PROPERTY_NAME = r'_$dart_jsObject';
 const _JS_FUNCTION_PROPERTY_NAME = r'$dart_jsFunction';
+const _JS_FUNCTION_PROPERTY_NAME_CAPTURE_THIS = r'_$dart_jsFunctionCaptureThis';
 
 bool _defineProperty(o, String name, value) {
   if (_isExtensible(o) &&
@@ -554,8 +564,13 @@ dynamic _convertToJS(dynamic o) {
   if (o is JsObject) {
     return o._jsObject;
   }
-  if (o is Blob || o is Event || o is KeyRange || o is ImageData || o is Node ||
-      o is TypedData || o is Window) {
+  if (o is Blob ||
+      o is Event ||
+      o is KeyRange ||
+      o is ImageData ||
+      o is Node ||
+      o is TypedData ||
+      o is Window) {
     return o;
   }
   if (o is DateTime) {
@@ -565,13 +580,13 @@ dynamic _convertToJS(dynamic o) {
     return _getJsProxy(o, _JS_FUNCTION_PROPERTY_NAME, (o) {
       var jsFunction = _convertDartFunction(o);
       // set a property on the JS closure referencing the Dart closure
-      _defineProperty(jsFunction, _DART_CLOSURE_PROPERTY_NAME, o);
+      _defineProperty(jsFunction, DART_CLOSURE_PROPERTY_NAME, o);
       return jsFunction;
     });
   }
   var ctor = _dartProxyCtor;
-  return _getJsProxy(o, _JS_OBJECT_PROPERTY_NAME,
-      (o) => JS('', 'new #(#)', ctor, o));
+  return _getJsProxy(
+      o, _JS_OBJECT_PROPERTY_NAME, (o) => JS('', 'new #(#)', ctor, o));
 }
 
 Object _getJsProxy(o, String propertyName, createProxy(o)) {
@@ -591,9 +606,14 @@ Object _convertToDart(o) {
       JS('bool', 'typeof # == "number"', o) ||
       JS('bool', 'typeof # == "boolean"', o)) {
     return o;
-  } else if (_isLocalObject(o)
-      && (o is Blob || o is Event || o is KeyRange || o is ImageData
-      || o is Node || o is TypedData || o is Window)) {
+  } else if (_isLocalObject(o) &&
+      (o is Blob ||
+          o is Event ||
+          o is KeyRange ||
+          o is ImageData ||
+          o is Node ||
+          o is TypedData ||
+          o is Window)) {
     // long line: dart2js doesn't allow string concatenation in the JS() form
     return JS('Blob|Event|KeyRange|ImageData|Node|TypedData|Window', '#', o);
   } else if (JS('bool', '# instanceof Date', o)) {
@@ -608,15 +628,15 @@ Object _convertToDart(o) {
 
 JsObject _wrapToDart(o) {
   if (JS('bool', 'typeof # == "function"', o)) {
-    return _getDartProxy(o, _DART_CLOSURE_PROPERTY_NAME,
-        (o) => new JsFunction._fromJs(o));
+    return _getDartProxy(
+        o, DART_CLOSURE_PROPERTY_NAME, (o) => new JsFunction._fromJs(o));
   }
   if (JS('bool', '# instanceof Array', o)) {
-    return _getDartProxy(o, _DART_OBJECT_PROPERTY_NAME,
-        (o) => new JsArray._fromJs(o));
+    return _getDartProxy(
+        o, _DART_OBJECT_PROPERTY_NAME, (o) => new JsArray._fromJs(o));
   }
-  return _getDartProxy(o, _DART_OBJECT_PROPERTY_NAME,
-      (o) => new JsObject._fromJs(o));
+  return _getDartProxy(
+      o, _DART_OBJECT_PROPERTY_NAME, (o) => new JsObject._fromJs(o));
 }
 
 Object _getDartProxy(o, String propertyName, createProxy(o)) {
@@ -634,3 +654,132 @@ Object _getDartProxy(o, String propertyName, createProxy(o)) {
   }
   return dartProxy;
 }
+
+// Start of methods for new style Dart-JS interop.
+
+class _JavaScriptFunctionHack implements Function {
+  call(
+      [a = const JS_CONST('void 0'),
+      b = const JS_CONST('void 0'),
+      c = const JS_CONST('void 0'),
+      d = const JS_CONST('void 0'),
+      e = const JS_CONST('void 0'),
+      f = const JS_CONST('void 0'),
+      g = const JS_CONST('void 0'),
+      h = const JS_CONST('void 0'),
+      i = const JS_CONST('void 0'),
+      j = const JS_CONST('void 0')]) {
+    // Exceedingly slow default implementation.
+    return JS('', '#.apply(null, #)', this,
+        _stripUndefinedArgs([a, b, c, d, e, f, g, h, i, j]));
+  }
+}
+
+void _copyOwnProperties(src, dest) {
+  JS(
+      '',
+      r"""(function(src, dest) {
+  var properties = Object.getOwnPropertyNames(src);
+  for (var i = 0, len = properties.length; i < len; i++) {
+    var name = properties[i];
+    dest[name] = src[name];
+  }
+})(#, #)""",
+      src,
+      dest);
+}
+
+// TODO(jacobr): remove this method. So far it appears that specifying the list
+// of registered types in Dart2Js has significant negative code size
+// implications so it is better to specify usage purely based on which
+// libraries are imported. Remove after Dartium is modified to function without

[Siggi Cherem (dart-lang), 2015/09/18 20:34:10]

would it make sense to use tree-shakeable lookup-maps to describe dependencies
between jsinterop types instead?

[Jacob, 2015/10/02 20:08:15]

could be. moved away from requiring this method instead.

+// requiring this method.
+void registerJsInterfaces([List<Type> types]) {

[Siggi Cherem (dart-lang), 2015/09/18 20:34:10]

I seem to be missing something, is `types` used anywhere? Only in the dartium
implementation?

You could also change this implementation to make it easier for dart2js to
inline it and decide that `types` is not used. For example, just doing a
forwarding call like this:

  registerJsInterfaces([types]) => _registerFunctionHacks();
  _registerFunctionHacks() {
   ...
  }

might be enough.

[Jacob, 2015/10/01 00:47:33]

This was used in Dartium. I've ripped it out there and just traversed all
libraries using mirrors. I think this method should get removed completely and
this code should be emitted directly in codegen if the new JS interop is used at
all. Sound reasonable?
On 2015/09/18 20:34:10, Siggi Cherem (dart-lang) wrote:

+  // No need to actually register in Dart2JS.
+  var fnHackProto = JS('', '#.__proto__', new _JavaScriptFunctionHack());
+  var fnProto = JS('', 'Function.prototype');
+  _copyOwnProperties(fnHackProto, fnProto);
+  // Add optimized call methods for small numbers of arguments.
+  if (JS('bool', r'#.hasOwnProperty("call$0") ', fnHackProto)) {
+    JS('', r'#.call$0 = function() { return this(); }', fnProto);
+    JS('', r'#.call$1 = function(a) { return this(a); }', fnProto);
+    JS('', r'#.call$2 = function(a, b) { return this(a, b); }', fnProto);
+    JS('', r'#.call$3 = function(a, b, c) { return this(a, b, c); }', fnProto);
+    JS('', r'#.call$4 = function(a, b, c, d) { return this(a, b, c, d); }',
+        fnProto);
+  } else {
+    if (!JS('bool', r'#.hasOwnProperty("$0") ', fnHackProto)) {
+      throw 'Internal error. Unexpected minified output';
+    }
+    JS('', r'#.$0 = function() { return this(); }', fnProto);
+    JS('', r'#.$1 = function(a) { return this(a); }', fnProto);
+    JS('', r'#.$2 = function(a, b) { return this(a, b); }', fnProto);
+    JS('', r'#.$3 = function(a, b, c) { return this(a, b, c); }', fnProto);
+    JS('', r'#.$4 = function(a, b, c, d) { return this(a, b, c, d); }',
+        fnProto);
+  }
+}
+
+_convertDartFunctionFast(Function f, {bool captureThis: false}) {
+  var existing = JS('', '#.#', f, _JS_FUNCTION_PROPERTY_NAME);
+  if (existing != null) return existing;
+  var ret = JS(
+      '',
+      'function(_call, f) {'
+      'return function() {'
+      'return _call(f, Array.prototype.slice.apply(arguments));'
+      '}'
+      '}(#, #)',
+      DART_CLOSURE_TO_JS(_callDartFunctionFast),
+      f);
+  JS('', '#.# = #', ret, DART_CLOSURE_PROPERTY_NAME, f);
+  JS('', '#.# = #', f, _JS_FUNCTION_PROPERTY_NAME, ret);
+  return ret;
+}
+
+_convertDartFunctionFastCaptureThis(Function f) {
+  var existing =
+      JS('', '#.#', f, _JS_FUNCTION_PROPERTY_NAME_CAPTURE_THIS);
+  if (existing != null) return existing;
+  var ret = JS(
+      '',
+      'function(_call, f) {'
+      'return function() {'
+      'return _call(f, this, '
+      'Array.prototype.slice.apply(arguments));'
+      '}'
+      '}(#, #)',
+      DART_CLOSURE_TO_JS(_callDartFunctionFastCaptureThis),
+      f);
+  JS('', '#.# = #', ret, DART_CLOSURE_PROPERTY_NAME, f);
+  JS('', '#.# = #', f, _JS_FUNCTION_PROPERTY_NAME_CAPTURE_THIS, ret);
+  return ret;
+}
+
+_callDartFunctionFast(callback, List arguments) {
+  return Function.apply(callback, arguments);
+}
+
+_callDartFunctionFastCaptureThis(callback, self, List arguments) {
+  return _convertToJS(Function.apply(callback, [self]..addAll(arguments)));
+}
+
+Function allowInterop(Function f) {
+  if (JS('bool', 'typeof(#) == "function"', f)) {
+    // Already supports interop, just use the existing function.
+    return f;
+  } else {
+    return _convertDartFunctionFast(f);
+  }
+}
+
+Function allowInteropCaptureThis(Function f) {
+  if (JS('bool', 'typeof(#) == "function"', f)) {
+    // Behavior when the function is already a JS function is unspecified.
+    throw new ArgumentError(
+        "Function is already a JS function so cannot capture this.");
+    return f;
+  } else {
+    return _convertDartFunctionFastCaptureThis(f);
+  }
+}