tools/dom/src/dart2js_Conversions.dart

// Copyright (c) 2012, 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.


// Conversions for Window.  These check if the window is the local
// window, and if it's not, wraps or unwraps it with a secure wrapper.
// We need to test for EventTarget here as well as it's a base type.
// We omit an unwrapper for Window as no methods take a non-local
// window as a parameter.

part of html;

DateTime _convertNativeToDart_DateTime(date) {
  var millisSinceEpoch = JS('int', '#.getTime()', date);
  return new DateTime.fromMillisecondsSinceEpoch(millisSinceEpoch, isUtc: true);
}

_convertDartToNative_DateTime(DateTime date) {
  return JS('', 'new Date(#)', date.millisecondsSinceEpoch);
}

WindowBase _convertNativeToDart_Window(win) {
  return _DOMWindowCrossFrame._createSafe(win);
}

EventTarget _convertNativeToDart_EventTarget(e) {
  // Assume it's a Window if it contains the setInterval property.  It may be
  // from a different frame - without a patched prototype - so we cannot
  // rely on Dart type checking.
  if (JS('bool', r'"setInterval" in #', e))
    return _DOMWindowCrossFrame._createSafe(e);
  else
    return e;
}

EventTarget _convertDartToNative_EventTarget(e) {
  if (e is _DOMWindowCrossFrame) {
    return e._window;
  } else {
    return e;
  }
}

// Conversions for ImageData
//
// On Firefox, the returned ImageData is a plain object.

class _TypedImageData implements ImageData {
  final Uint8ClampedArray data;
  final int height;
  final int width;

  _TypedImageData(this.data, this.height, this.width);
}

ImageData _convertNativeToDart_ImageData(nativeImageData) {

  // None of the native getters that return ImageData have the type ImageData
  // since that is incorrect for FireFox (which returns a plain Object).  So we
  // need something that tells the compiler that the ImageData class has been
  // instantiated.
  // TODO(sra): Remove this when all the ImageData returning APIs have been
  // annotated as returning the union ImageData + Object.
  JS('ImageData', '0');

  if (nativeImageData is ImageData) return nativeImageData;

  // On Firefox the above test fails because imagedata is a plain object.
  // So we create a _TypedImageData.

  return new _TypedImageData(
      JS('var', '#.data', nativeImageData),
      JS('var', '#.height', nativeImageData),
      JS('var', '#.width', nativeImageData));
}

// We can get rid of this conversion if _TypedImageData implements the fields
// with native names.
_convertDartToNative_ImageData(ImageData imageData) {
  if (imageData is _TypedImageData) {
    return JS('', '{data: #, height: #, width: #}',
        imageData.data, imageData.height, imageData.width);
  }
  return imageData;
}