tools/dom/src/native_DOMImplementation.dart - sdk.git - Git at Google

 // 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.

 part of html;

 class _Utils {
   static double dateTimeToDouble(DateTime dateTime) =>
       dateTime.millisecondsSinceEpoch.toDouble();
   static DateTime doubleToDateTime(double dateTime) {
     try {
       return new DateTime.fromMillisecondsSinceEpoch(dateTime.toInt());
     } catch(_) {
       // TODO(antonnm): treat exceptions properly in bindings and
       // find out how to treat NaNs.
       return null;
     }
   }

   static List convertToList(List list) {
     // FIXME: [possible optimization]: do not copy the array if Dart_IsArray is fine w/ it.
     final length = list.length;
     List result = new List(length);
     result.setRange(0, length, list);
     return result;
   }

   static List convertMapToList(Map map) {
     List result = [];
     map.forEach((k, v) => result.addAll([k, v]));
     return result;
   }

   static int convertCanvasElementGetContextMap(Map map) {
     int result = 0;
     if (map['alpha'] == true) result |= 0x01;
     if (map['depth'] == true) result |= 0x02;
     if (map['stencil'] == true) result |= 0x4;
     if (map['antialias'] == true) result |= 0x08;
     if (map['premultipliedAlpha'] == true) result |= 0x10;
     if (map['preserveDrawingBuffer'] == true) result |= 0x20;

     return result;
   }

   static List parseStackTrace(StackTrace stackTrace) {
     final regExp = new RegExp(r'#\d\s+(.*) \((.*):(\d+):(\d+)\)');
     List result = [];
     for (var match in regExp.allMatches(stackTrace.toString())) {
       result.add([match.group(1), match.group(2), int.parse(match.group(3)), int.parse(match.group(4))]);
     }
     return result;
   }

   static void populateMap(Map result, List list) {
     for (int i = 0; i < list.length; i += 2) {
       result[list[i]] = list[i + 1];
     }
   }

   static bool isMap(obj) => obj is Map;

   static Map createMap() => {};

   static makeUnimplementedError(String fileName, int lineNo) {
     return new UnsupportedError('[info: $fileName:$lineNo]');
   }

   static window() native "Utils_window";
   static forwardingPrint(String message) native "Utils_forwardingPrint";
   static void spawnDomFunction(Function f, int replyTo) native "Utils_spawnDomFunction";
   static void spawnDomUri(String uri, int replyTo) native "Utils_spawnDomUri";
   static int _getNewIsolateId() native "Utils_getNewIsolateId";

   // The following methods were added for debugger integration to make working
   // with the Dart C mirrors API simpler.
   // TODO(jacobr): consider moving them to a separate library.
   // If Dart supported dynamic code injection, we would only inject this code
   // when the debugger is invoked.

   /**
    * Strips the private secret prefix from member names of the form
    * someName@hash.
    */
   static String stripMemberName(String name) {
     int endIndex = name.indexOf('@');
     return endIndex > 0 ? name.substring(0, endIndex) : name;
   }

   /**
    * Takes a list containing variable names and corresponding values and
    * returns a map from normalized names to values. Variable names are assumed
    * to have list offsets 2*n values at offset 2*n+1. This method is required
    * because Dart_GetLocalVariables returns a list instead of an object that
    * can be queried to lookup names and values.
    */
   static Map<String, dynamic> createLocalVariablesMap(List localVariables) {
     var map = {};
     for (int i = 0; i < localVariables.length; i+=2) {
       map[stripMemberName(localVariables[i])] = localVariables[i+1];
     }
     return map;
   }

   /**
    * Convenience helper to get the keys of a [Map] as a [List].
    */
   static List getMapKeyList(Map map) => map.keys.toList();

  /**
    * Returns the keys of an arbitrary Dart Map encoded as unique Strings.
    * Keys that are strings are left unchanged except that the prefix ":" is
    * added to disambiguate keys from other Dart members.
    * Keys that are not strings have # followed by the index of the key in the map
    * prepended to disambuguate. This scheme is simplistic but easy to encode and
    * decode. The use case for this method is displaying all map keys in a human
    * readable way in debugging tools.
    */
   static List<String> getEncodedMapKeyList(dynamic obj) {
     if (obj is! Map) return null;

     var ret = new List<String>();
     int i = 0;
     return obj.keys.map((key) {
       var encodedKey;
       if (key is String) {
         encodedKey = ':$key';
       } else {
         // If the key isn't a string, return a guaranteed unique for this map
         // string representation of the key that is still somewhat human
         // readable.
         encodedKey = '#${i}:$key';
       }
       i++;
       return encodedKey;
     }).toList(growable: false);
   }

   static final RegExp _NON_STRING_KEY_REGEXP = new RegExp("^#(\\d+):(.+)\$");

   static _decodeKey(Map map, String key) {
     // The key is a regular old String.
     if (key.startsWith(':')) return key.substring(1);

     var match = _NON_STRING_KEY_REGEXP.firstMatch(key);
     if (match != null) {
       int index = int.parse(match.group(1));
       var iter = map.keys.skip(index);
       if (iter.isNotEmpty) {
         var ret = iter.first;
         // Validate that the toString representation of the key matches what we
         // expect. FIXME: throw an error if it does not.
         assert(match.group(2) == '$ret');
         return ret;
       }
     }
     return null;
   }

   /**
    * Converts keys encoded with [getEncodedMapKeyList] to their actual keys.
    */
   static lookupValueForEncodedMapKey(Map obj, String key) => obj[_decodeKey(obj, key)];

   /**
    * Builds a constructor name with the form expected by the C Dart mirrors API.
    */
   static String buildConstructorName(String className, String constructorName) => '$className.$constructorName';

   /**
    * Strips the class name from an expression of the form "className.someName".
    */
   static String stripClassName(String str, String className) {
     if (str.length > className.length + 1 &&
         str.startsWith(className) && str[className.length] == '.') {
       return str.substring(className.length + 1);
     } else {
       return str;
     }
   }

   /**
    * Removes the trailing dot from an expression ending in a dot.
    * This method is used as Library prefixes include a trailing dot when using
    * the C Dart debugger API.
    */
   static String stripTrailingDot(String str) =>
     (str != null && str[str.length - 1] == '.') ? str.substring(0, str.length - 1) : str;

   static String addTrailingDot(String str) => '${str}.';

   // TODO(jacobr): we need a failsafe way to determine that a Node is really a
   // DOM node rather than just a class that extends Node.
   static bool isNode(obj) => obj is Node;
 }

 class _NPObject extends NativeFieldWrapperClass1 {
   _NPObject.internal();
   static _NPObject retrieve(String key) native "NPObject_retrieve";
   property(String propertyName) native "NPObject_property";
   invoke(String methodName, [List args = null]) native "NPObject_invoke";
 }

 class _DOMWindowCrossFrame extends NativeFieldWrapperClass1 implements
     WindowBase {
   _DOMWindowCrossFrame.internal();

   // Fields.
   HistoryBase get history native "Window_history_cross_frame_Getter";
   LocationBase get location native "Window_location_cross_frame_Getter";
   bool get closed native "Window_closed_Getter";
   int get length native "Window_length_Getter";
   WindowBase get opener native "Window_opener_Getter";
   WindowBase get parent native "Window_parent_Getter";
   WindowBase get top native "Window_top_Getter";

   // Methods.
   void close() native "Window_close_Callback";
   void postMessage(/*SerializedScriptValue*/ message, String targetOrigin, [List messagePorts]) native "Window_postMessage_Callback";

   // Implementation support.
   String get typeName => "Window";
 }

 class _HistoryCrossFrame extends NativeFieldWrapperClass1 implements HistoryBase {
   _HistoryCrossFrame.internal();

   // Methods.
   void back() native "History_back_Callback";
   void forward() native "History_forward_Callback";
   void go(int distance) native "History_go_Callback";

   // Implementation support.
   String get typeName => "History";
 }

 class _LocationCrossFrame extends NativeFieldWrapperClass1 implements LocationBase {
   _LocationCrossFrame.internal();

   // Fields.
   void set href(String) native "Location_href_Setter";

   // Implementation support.
   String get typeName => "Location";
 }

 class _DOMStringMap extends NativeFieldWrapperClass1 implements Map<String, String> {
   _DOMStringMap.internal();

   bool containsValue(String value) => Maps.containsValue(this, value);
   bool containsKey(String key) native "DOMStringMap_containsKey_Callback";
   String operator [](String key) native "DOMStringMap_item_Callback";
   void operator []=(String key, String value) native "DOMStringMap_setItem_Callback";
   String putIfAbsent(String key, String ifAbsent()) => Maps.putIfAbsent(this, key, ifAbsent);
   String remove(String key) native "DOMStringMap_remove_Callback";
   void clear() => Maps.clear(this);
   void forEach(void f(String key, String value)) => Maps.forEach(this, f);
   Iterable<String> get keys native "DOMStringMap_getKeys_Callback";
   Iterable<String> get values => Maps.getValues(this);
   int get length => Maps.length(this);
   bool get isEmpty => Maps.isEmpty(this);
   bool get isNotEmpty => Maps.isNotEmpty(this);
 }

 final Future<SendPort> __HELPER_ISOLATE_PORT =
     spawnDomFunction(_helperIsolateMain);

 // Tricky part.
 // Once __HELPER_ISOLATE_PORT gets resolved, it will still delay in .then
 // and to delay Timer.run is used. However, Timer.run will try to register
 // another Timer and here we got stuck: event cannot be posted as then
 // callback is not executed because it's delayed with timer.
 // Therefore once future is resolved, it's unsafe to call .then on it
 // in Timer code.
 SendPort __SEND_PORT;

 _sendToHelperIsolate(msg, SendPort replyTo) {
   if (__SEND_PORT != null) {
     __SEND_PORT.send(msg, replyTo);
   } else {
     __HELPER_ISOLATE_PORT.then((port) {
       __SEND_PORT = port;
       __SEND_PORT.send(msg, replyTo);
     });
   }
 }

 final _TIMER_REGISTRY = new Map<SendPort, Timer>();

 const _NEW_TIMER = 'NEW_TIMER';
 const _CANCEL_TIMER = 'CANCEL_TIMER';
 const _TIMER_PING = 'TIMER_PING';
 const _PRINT = 'PRINT';

 _helperIsolateMain() {
   port.receive((msg, replyTo) {
     final cmd = msg[0];
     if (cmd == _NEW_TIMER) {
       final duration = new Duration(milliseconds: msg[1]);
       bool periodic = msg[2];
       ping() { replyTo.send(_TIMER_PING); };
       _TIMER_REGISTRY[replyTo] = periodic ?
           new Timer.periodic(duration, (_) { ping(); }) :
           new Timer(duration, ping);
     } else if (cmd == _CANCEL_TIMER) {
       _TIMER_REGISTRY.remove(replyTo).cancel();
     } else if (cmd == _PRINT) {
       final message = msg[1];
       // TODO(antonm): we need somehow identify those isolates.
       print('[From isolate] $message');
     }
   });
 }

 final _printClosure = window.console.log;
 final _pureIsolatePrintClosure = (s) {
   _sendToHelperIsolate([_PRINT, s], null);
 };

 final _forwardingPrintClosure = _Utils.forwardingPrint;

  class _Timer implements Timer{
   var _canceler;

   _Timer(int milliSeconds, void callback(Timer timer), bool repeating) {

     if (repeating) {
       int id = window._setInterval(() {
         callback(this);
       }, milliSeconds);
       _canceler = () => window._clearInterval(id);
     } else {
       int id = window._setTimeout(() {
         _canceler = null;
         callback(this);
       }, milliSeconds);
       _canceler = () => window._clearTimeout(id);
     }
   }

   void cancel() {
     if (_canceler != null) {
       _canceler();
     }
     _canceler = null;
   }

   bool get isActive => _canceler != null;
 }

 get _timerFactoryClosure =>
     (int milliSeconds, void callback(Timer timer), bool repeating) {
   return new _Timer(milliSeconds, callback, repeating);
 };


 class _PureIsolateTimer implements Timer {
   bool _isActive = true;
   final ReceivePort _port = new ReceivePort();
   SendPort _sendPort; // Effectively final.

   static SendPort _SEND_PORT;

   _PureIsolateTimer(int milliSeconds, callback, repeating) {
     _sendPort = _port.toSendPort();
     _port.receive((msg, replyTo) {
       assert(msg == _TIMER_PING);
       _isActive = repeating;
       callback(this);
       if (!repeating) _cancel();
     });

     _send([_NEW_TIMER, milliSeconds, repeating]);
   }

   void cancel() {
     _cancel();
     _send([_CANCEL_TIMER]);
   }

   void _cancel() {
     _isActive = false;
     _port.close();
   }

   _send(msg) {
     _sendToHelperIsolate(msg, _sendPort);
   }

   bool get isActive => _isActive;
 }

 get _pureIsolateTimerFactoryClosure =>
     ((int milliSeconds, void callback(Timer time), bool repeating) =>
         new _PureIsolateTimer(milliSeconds, callback, repeating));
	// 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.

	part of html;

	class _Utils {
	static double dateTimeToDouble(DateTime dateTime) =>
	dateTime.millisecondsSinceEpoch.toDouble();
	static DateTime doubleToDateTime(double dateTime) {
	try {
	return new DateTime.fromMillisecondsSinceEpoch(dateTime.toInt());
	} catch(_) {
	// TODO(antonnm): treat exceptions properly in bindings and
	// find out how to treat NaNs.
	return null;
	}
	}

	static List convertToList(List list) {
	// FIXME: [possible optimization]: do not copy the array if Dart_IsArray is fine w/ it.
	final length = list.length;
	List result = new List(length);
	result.setRange(0, length, list);
	return result;
	}

	static List convertMapToList(Map map) {
	List result = [];
	map.forEach((k, v) => result.addAll([k, v]));
	return result;
	}

	static int convertCanvasElementGetContextMap(Map map) {
	int result = 0;
	if (map['alpha'] == true) result \|= 0x01;
	if (map['depth'] == true) result \|= 0x02;
	if (map['stencil'] == true) result \|= 0x4;
	if (map['antialias'] == true) result \|= 0x08;
	if (map['premultipliedAlpha'] == true) result \|= 0x10;
	if (map['preserveDrawingBuffer'] == true) result \|= 0x20;

	return result;
	}

	static List parseStackTrace(StackTrace stackTrace) {
	final regExp = new RegExp(r'#\d\s+(.) \((.):(\d+):(\d+)\)');
	List result = [];
	for (var match in regExp.allMatches(stackTrace.toString())) {
	result.add([match.group(1), match.group(2), int.parse(match.group(3)), int.parse(match.group(4))]);
	}
	return result;
	}

	static void populateMap(Map result, List list) {
	for (int i = 0; i < list.length; i += 2) {
	result[list[i]] = list[i + 1];
	}
	}

	static bool isMap(obj) => obj is Map;

	static Map createMap() => {};

	static makeUnimplementedError(String fileName, int lineNo) {
	return new UnsupportedError('[info: $fileName:$lineNo]');
	}

	static window() native "Utils_window";
	static forwardingPrint(String message) native "Utils_forwardingPrint";
	static void spawnDomFunction(Function f, int replyTo) native "Utils_spawnDomFunction";
	static void spawnDomUri(String uri, int replyTo) native "Utils_spawnDomUri";
	static int _getNewIsolateId() native "Utils_getNewIsolateId";

	// The following methods were added for debugger integration to make working
	// with the Dart C mirrors API simpler.
	// TODO(jacobr): consider moving them to a separate library.
	// If Dart supported dynamic code injection, we would only inject this code
	// when the debugger is invoked.

	/**
	* Strips the private secret prefix from member names of the form
	* someName@hash.
	*/
	static String stripMemberName(String name) {
	int endIndex = name.indexOf('@');
	return endIndex > 0 ? name.substring(0, endIndex) : name;
	}

	/**
	* Takes a list containing variable names and corresponding values and
	* returns a map from normalized names to values. Variable names are assumed
	* to have list offsets 2n values at offset 2n+1. This method is required
	* because Dart_GetLocalVariables returns a list instead of an object that
	* can be queried to lookup names and values.
	*/
	static Map<String, dynamic> createLocalVariablesMap(List localVariables) {
	var map = {};
	for (int i = 0; i < localVariables.length; i+=2) {
	map[stripMemberName(localVariables[i])] = localVariables[i+1];
	}
	return map;
	}

	/**
	* Convenience helper to get the keys of a [Map] as a [List].
	*/
	static List getMapKeyList(Map map) => map.keys.toList();

	/**
	* Returns the keys of an arbitrary Dart Map encoded as unique Strings.
	* Keys that are strings are left unchanged except that the prefix ":" is
	* added to disambiguate keys from other Dart members.
	* Keys that are not strings have # followed by the index of the key in the map
	* prepended to disambuguate. This scheme is simplistic but easy to encode and
	* decode. The use case for this method is displaying all map keys in a human
	* readable way in debugging tools.
	*/
	static List<String> getEncodedMapKeyList(dynamic obj) {
	if (obj is! Map) return null;

	var ret = new List<String>();
	int i = 0;
	return obj.keys.map((key) {
	var encodedKey;
	if (key is String) {
	encodedKey = ':$key';
	} else {
	// If the key isn't a string, return a guaranteed unique for this map
	// string representation of the key that is still somewhat human
	// readable.
	encodedKey = '#${i}:$key';
	}
	i++;
	return encodedKey;
	}).toList(growable: false);
	}

	static final RegExp _NON_STRING_KEY_REGEXP = new RegExp("^#(\\d+):(.+)\$");

	static _decodeKey(Map map, String key) {
	// The key is a regular old String.
	if (key.startsWith(':')) return key.substring(1);

	var match = _NON_STRING_KEY_REGEXP.firstMatch(key);
	if (match != null) {
	int index = int.parse(match.group(1));
	var iter = map.keys.skip(index);
	if (iter.isNotEmpty) {
	var ret = iter.first;
	// Validate that the toString representation of the key matches what we
	// expect. FIXME: throw an error if it does not.
	assert(match.group(2) == '$ret');
	return ret;
	}
	}
	return null;
	}

	/**
	* Converts keys encoded with [getEncodedMapKeyList] to their actual keys.
	*/
	static lookupValueForEncodedMapKey(Map obj, String key) => obj[_decodeKey(obj, key)];

	/**
	* Builds a constructor name with the form expected by the C Dart mirrors API.
	*/
	static String buildConstructorName(String className, String constructorName) => '$className.$constructorName';

	/**
	* Strips the class name from an expression of the form "className.someName".
	*/
	static String stripClassName(String str, String className) {
	if (str.length > className.length + 1 &&
	str.startsWith(className) && str[className.length] == '.') {
	return str.substring(className.length + 1);
	} else {
	return str;
	}
	}

	/**
	* Removes the trailing dot from an expression ending in a dot.
	* This method is used as Library prefixes include a trailing dot when using
	* the C Dart debugger API.
	*/
	static String stripTrailingDot(String str) =>
	(str != null && str[str.length - 1] == '.') ? str.substring(0, str.length - 1) : str;

	static String addTrailingDot(String str) => '${str}.';

	// TODO(jacobr): we need a failsafe way to determine that a Node is really a
	// DOM node rather than just a class that extends Node.
	static bool isNode(obj) => obj is Node;
	}

	class _NPObject extends NativeFieldWrapperClass1 {
	_NPObject.internal();
	static _NPObject retrieve(String key) native "NPObject_retrieve";
	property(String propertyName) native "NPObject_property";
	invoke(String methodName, [List args = null]) native "NPObject_invoke";
	}

	class _DOMWindowCrossFrame extends NativeFieldWrapperClass1 implements
	WindowBase {
	_DOMWindowCrossFrame.internal();

	// Fields.
	HistoryBase get history native "Window_history_cross_frame_Getter";
	LocationBase get location native "Window_location_cross_frame_Getter";
	bool get closed native "Window_closed_Getter";
	int get length native "Window_length_Getter";
	WindowBase get opener native "Window_opener_Getter";
	WindowBase get parent native "Window_parent_Getter";
	WindowBase get top native "Window_top_Getter";

	// Methods.
	void close() native "Window_close_Callback";
	void postMessage(/SerializedScriptValue/ message, String targetOrigin, [List messagePorts]) native "Window_postMessage_Callback";

	// Implementation support.
	String get typeName => "Window";
	}

	class _HistoryCrossFrame extends NativeFieldWrapperClass1 implements HistoryBase {
	_HistoryCrossFrame.internal();

	// Methods.
	void back() native "History_back_Callback";
	void forward() native "History_forward_Callback";
	void go(int distance) native "History_go_Callback";

	// Implementation support.
	String get typeName => "History";
	}

	class _LocationCrossFrame extends NativeFieldWrapperClass1 implements LocationBase {
	_LocationCrossFrame.internal();

	// Fields.
	void set href(String) native "Location_href_Setter";

	// Implementation support.
	String get typeName => "Location";
	}

	class _DOMStringMap extends NativeFieldWrapperClass1 implements Map<String, String> {
	_DOMStringMap.internal();

	bool containsValue(String value) => Maps.containsValue(this, value);
	bool containsKey(String key) native "DOMStringMap_containsKey_Callback";
	String operator [](String key) native "DOMStringMap_item_Callback";
	void operator []=(String key, String value) native "DOMStringMap_setItem_Callback";
	String putIfAbsent(String key, String ifAbsent()) => Maps.putIfAbsent(this, key, ifAbsent);
	String remove(String key) native "DOMStringMap_remove_Callback";
	void clear() => Maps.clear(this);
	void forEach(void f(String key, String value)) => Maps.forEach(this, f);
	Iterable<String> get keys native "DOMStringMap_getKeys_Callback";
	Iterable<String> get values => Maps.getValues(this);
	int get length => Maps.length(this);
	bool get isEmpty => Maps.isEmpty(this);
	bool get isNotEmpty => Maps.isNotEmpty(this);
	}

	final Future<SendPort> __HELPER_ISOLATE_PORT =
	spawnDomFunction(_helperIsolateMain);

	// Tricky part.
	// Once __HELPER_ISOLATE_PORT gets resolved, it will still delay in .then
	// and to delay Timer.run is used. However, Timer.run will try to register
	// another Timer and here we got stuck: event cannot be posted as then
	// callback is not executed because it's delayed with timer.
	// Therefore once future is resolved, it's unsafe to call .then on it
	// in Timer code.
	SendPort __SEND_PORT;

	_sendToHelperIsolate(msg, SendPort replyTo) {
	if (__SEND_PORT != null) {
	__SEND_PORT.send(msg, replyTo);
	} else {
	__HELPER_ISOLATE_PORT.then((port) {
	__SEND_PORT = port;
	__SEND_PORT.send(msg, replyTo);
	});
	}
	}

	final _TIMER_REGISTRY = new Map<SendPort, Timer>();

	const _NEW_TIMER = 'NEW_TIMER';
	const _CANCEL_TIMER = 'CANCEL_TIMER';
	const _TIMER_PING = 'TIMER_PING';
	const _PRINT = 'PRINT';

	_helperIsolateMain() {
	port.receive((msg, replyTo) {
	final cmd = msg[0];
	if (cmd == _NEW_TIMER) {
	final duration = new Duration(milliseconds: msg[1]);
	bool periodic = msg[2];
	ping() { replyTo.send(_TIMER_PING); };
	_TIMER_REGISTRY[replyTo] = periodic ?
	new Timer.periodic(duration, (_) { ping(); }) :
	new Timer(duration, ping);
	} else if (cmd == _CANCEL_TIMER) {
	_TIMER_REGISTRY.remove(replyTo).cancel();
	} else if (cmd == _PRINT) {
	final message = msg[1];
	// TODO(antonm): we need somehow identify those isolates.
	print('[From isolate] $message');
	}
	});
	}

	final _printClosure = window.console.log;
	final _pureIsolatePrintClosure = (s) {
	_sendToHelperIsolate([_PRINT, s], null);
	};

	final _forwardingPrintClosure = _Utils.forwardingPrint;

	class _Timer implements Timer{
	var _canceler;

	_Timer(int milliSeconds, void callback(Timer timer), bool repeating) {

	if (repeating) {
	int id = window._setInterval(() {
	callback(this);
	}, milliSeconds);
	_canceler = () => window._clearInterval(id);
	} else {
	int id = window._setTimeout(() {
	_canceler = null;
	callback(this);
	}, milliSeconds);
	_canceler = () => window._clearTimeout(id);
	}
	}

	void cancel() {
	if (_canceler != null) {
	_canceler();
	}
	_canceler = null;
	}

	bool get isActive => _canceler != null;
	}

	get _timerFactoryClosure =>
	(int milliSeconds, void callback(Timer timer), bool repeating) {
	return new _Timer(milliSeconds, callback, repeating);
	};


	class _PureIsolateTimer implements Timer {
	bool _isActive = true;
	final ReceivePort _port = new ReceivePort();
	SendPort _sendPort; // Effectively final.

	static SendPort _SEND_PORT;

	_PureIsolateTimer(int milliSeconds, callback, repeating) {
	_sendPort = _port.toSendPort();
	_port.receive((msg, replyTo) {
	assert(msg == _TIMER_PING);
	_isActive = repeating;
	callback(this);
	if (!repeating) _cancel();
	});

	_send([_NEW_TIMER, milliSeconds, repeating]);
	}

	void cancel() {
	_cancel();
	_send([_CANCEL_TIMER]);
	}

	void _cancel() {
	_isActive = false;
	_port.close();
	}

	_send(msg) {
	_sendToHelperIsolate(msg, _sendPort);
	}

	bool get isActive => _isActive;
	}

	get _pureIsolateTimerFactoryClosure =>
	((int milliSeconds, void callback(Timer time), bool repeating) =>
	new _PureIsolateTimer(milliSeconds, callback, repeating));