isolate in frog: hiding internal implementation classes, couple minor fixes.

lib/isolate/frog/isolateimpl.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.
 
 /**
  * A native object that is shared across isolates. This object is visible to all
  * isolates running on the same worker (either UI or background web worker).
  *
  * This is code that is intended to 'escape' the isolate boundaries in order to
  * implement the semantics of isolates in JavaScript. Without this we would have
  * been forced to implement more code (including the top-level event loop) in
  * JavaScript itself.
  */
-GlobalState get globalState() native "return \$globalState;";
-set globalState(GlobalState val) native "\$globalState = val;";
+_GlobalState get _globalState() native "return \$globalState;";
+set _globalState(_GlobalState val) native "\$globalState = val;";
 
-void fillStatics(context) native @"""
+void _fillStatics(context) native @"""
   $globals = context.isolateStatics;
   $static_init();
 """;
 
 /** Global state associated with the current worker. See [globalState]. */
 // TODO(sigmund): split in multiple classes: global, thread, main-worker states?
-class GlobalState {
+class _GlobalState {
 
   /** Next available isolate id. */
   int nextIsolateId = 0;
 
   /** Worker id associated with this worker. */
   int currentWorkerId = 0;
 
   /**
    * Next available worker id. Only used by the main worker to assign a unique
    * id to each worker created by it.
    */
   int nextWorkerId = 1;
 
   /** Context for the currently running [Isolate]. */
-  IsolateContext currentContext = null;
+  _IsolateContext currentContext = null;
 
   /** Context for the root [Isolate] that first run in this worker. */
-  IsolateContext rootContext = null;
+  _IsolateContext rootContext = null;
 
   /** The top-level event loop. */
-  EventLoop topEventLoop;
+  _EventLoop topEventLoop;
 
   /** Whether this program is running in a background worker. */
   bool isWorker;
 
   /** Whether this program is running in a UI worker. */
   bool inWindow;
 
   /** Whether we support spawning workers. */
   bool supportsWorkers;
 
   /**
    * Whether to use web workers when implementing isolates. Set to false for
    * debugging/testing.
    */
   bool get useWorkers() => supportsWorkers;
 
   /**
    * Whether to use the web-worker JSON-based message serialization protocol. By
    * default this is only used with web workers. For debugging, you can force
    * using this protocol by changing this field value to [true].
    */
   bool get needSerialization() => useWorkers;
 
   /**
    * Registry of isolates. Isolates must be registered if, and only if, receive
    * ports are alive.  Normally no open receive-ports means that the isolate is
    * dead, but DOM callbacks could resurrect it.
    */
-  Map<int, IsolateContext> isolates;
+  Map<int, _IsolateContext> isolates;
 
   /** Reference to the main worker. */
-  MainWorker mainWorker;
+  _MainWorker mainWorker;
 
   /** Registry of active workers. Only used in the main worker. */
   Map<int, Dynamic> workers;
 
-  GlobalState() {
-    topEventLoop = new EventLoop();
+  _GlobalState() {
+    topEventLoop = new _EventLoop();
     isolates = {};
     workers = {};
-    mainWorker = new MainWorker();
+    mainWorker = new _MainWorker();
     _nativeInit();
   }
 
   void _nativeInit() native @"""
     this.isWorker = typeof ($globalThis['importScripts']) != 'undefined';
     this.inWindow = typeof(window) !== 'undefined';
     this.supportsWorkers = this.isWorker ||
         ((typeof $globalThis['Worker']) != 'undefined');
-
-    // if workers are supported, treat this as a main worker:
-    if (this.supportsWorkers) {
-      $globalThis.onmessage = function(e) {
+    if (this.isWorker) {
+      $globalThis.onmessage = function (e) {
         _IsolateNatives._processWorkerMessage(this.mainWorker, e);
       };
     }
   """ {
     // Declare that the native code has a dependency on this fn.
     _IsolateNatives._processWorkerMessage(null, null);
   }
 
   /**
    * Close the worker running this code, called when there is nothing else to
    * run.
    */
   void closeWorker() {
     if (isWorker) {
       if (!isolates.isEmpty()) return;
       mainWorker.postMessage(
           _serializeMessage({'command': 'close'}));
     } else if (isolates.containsKey(rootContext.id) && workers.isEmpty() &&
                !supportsWorkers && !inWindow) {
       // This should only trigger when running on the command-line.
       // We don't want this check to execute in the browser where the isolate
       // might still be alive due to DOM callbacks.
       throw new Exception("Program exited with open ReceivePorts.");
     }
   }
 }
 
 /** Context information tracked for each isolate. */
-class IsolateContext {
+class _IsolateContext {
   /** Current isolate id. */
   int id;
 
   /** Registry of receive ports currently active on this isolate. */
   Map<int, ReceivePort> ports;
 
   /** Holds isolate globals (statics and top-level properties). */
   var isolateStatics; // native object containing all globals of an isolate.
 
-  IsolateContext() {
-    id = globalState.nextIsolateId++;
+  _IsolateContext() {
+    id = _globalState.nextIsolateId++;
     ports = {};
     initGlobals();
   }
 
   // these are filled lazily the first time the isolate starts running.
   void initGlobals() native 'this.isolateStatics = {};';
 
   /**
    * Run [code] in the context of the isolate represented by [this]. Note this
    * is called from JavaScript (see $wrap_call in corejs.dart).
    */
   void eval(Function code) {
-    var old = globalState.currentContext;
-    globalState.currentContext = this;
+    var old = _globalState.currentContext;
+    _globalState.currentContext = this;
     this._setGlobals();
     var result = null;
     try {
       result = code();
     } finally {
-      globalState.currentContext = old;
+      _globalState.currentContext = old;
       if (old != null) old._setGlobals();
     }
     return result;
   }
 
   void _setGlobals() native @'$globals = this.isolateStatics;';
 
   /** Lookup a port registered for this isolate. */
   ReceivePort lookup(int id) => ports[id];
 
   /** Register a port on this isolate. */
   void register(int portId, ReceivePort port)  {
     if (ports.containsKey(portId)) {
       throw new Exception("Registry: ports must be registered only once.");
     }
     ports[portId] = port;
-    globalState.isolates[id] = this; // indicate this isolate is active
+    _globalState.isolates[id] = this; // indicate this isolate is active
   }
 
   /** Unregister a port on this isolate. */
   void unregister(int portId) {
     ports.remove(portId);
     if (ports.isEmpty()) {
-      globalState.isolates.remove(id); // indicate this isolate is not active
+      _globalState.isolates.remove(id); // indicate this isolate is not active
     }
   }
 }
 
 
 /** Represent the event loop on a javascript thread (DOM or worker). */
-class EventLoop {
-  Queue<IsolateEvent> events;
+class _EventLoop {
+  Queue<_IsolateEvent> events;
 
-  EventLoop() : events = new Queue<IsolateEvent>();
+  _EventLoop() : events = new Queue<_IsolateEvent>();
 
   void enqueue(isolate, fn, msg) {
-    events.addLast(new IsolateEvent(isolate, fn, msg));
+    events.addLast(new _IsolateEvent(isolate, fn, msg));
   }
 
-  IsolateEvent dequeue() {
+  _IsolateEvent dequeue() {
     if (events.isEmpty()) return null;
     return events.removeFirst();
   }
 
   /** Process a single event, if any. */
   bool runIteration() {
     final event = dequeue();
     if (event == null) {
-      globalState.closeWorker();
+      _globalState.closeWorker();
       return false;
     }
     event.process();
     return true;
   }
 
   /** Function equivalent to [:window.setTimeout:] when available, or null. */
   static Function _wrapSetTimeout() native """
       return typeof window != 'undefined' ?
           function(a, b) { window.setTimeout(a, b); } : undefined;
@@ skipping 16 matching lines @@
       // Run synchronously until no more iterations are available.
       while (runIteration()) {}
     }
   }
 
   /**
    * Call [_runHelper] but ensure that worker exceptions are propragated. Note
    * this is called from JavaScript (see $wrap_call in corejs.dart).
    */
   void run() {
-    if (!globalState.isWorker) {
+    if (!_globalState.isWorker) {
       _runHelper();
     } else {
       try {
         _runHelper();
       } catch(var e, var trace) {
-        globalState.mainWorker.postMessage(_serializeMessage(
+        _globalState.mainWorker.postMessage(_serializeMessage(
             {'command': 'error', 'msg': '$e\n$trace' }));
       }
     }
   }
 }
 
 /** An event in the top-level event queue. */
-class IsolateEvent {
-  IsolateContext isolate;
+class _IsolateEvent {
+  _IsolateContext isolate;
   Function fn;
   String message;
 
-  IsolateEvent(this.isolate, this.fn, this.message);
+  _IsolateEvent(this.isolate, this.fn, this.message);
 
   void process() {
     isolate.eval(fn);
   }
 }
 
 
 /** Default worker. */
-class MainWorker {
+class _MainWorker {
   int id = 0;
-  void postMessage(msg) native "return \$globalThis.postMessage(msg);";
-  void set onmessage(f) native "\$globalThis.onmessage = f;";
+  void postMessage(msg) native @"$globalThis.postMessage(msg);";
   void terminate() {}
 }
 
 /**
  * A web worker. This type is also defined in 'dart:dom', but we define it here
  * to avoid introducing a dependency from corelib to dom. This definition uses a
  * 'hidden' type (* prefix on the native name) to enforce that the type is
  * defined dynamically only when web workers are actually available.
  */
 class _Worker native "*Worker" {
@@ skipping 11 matching lines @@
   static Future<SendPort> spawn(Isolate isolate, bool isLight) {
     Completer<SendPort> completer = new Completer<SendPort>();
     ReceivePort port = new ReceivePort.singleShot();
     port.receive((msg, SendPort replyPort) {
       assert(msg == _SPAWNED_SIGNAL);
       completer.complete(replyPort);
     });
 
     // TODO(floitsch): throw exception if isolate's class doesn't have a
     // default constructor.
-    if (globalState.useWorkers && !isLight) {
+    if (_globalState.useWorkers && !isLight) {
       _startWorker(isolate, port.toSendPort());
     } else {
       _startNonWorker(isolate, port.toSendPort());
     }
 
     return completer.future;
   }
 
   static SendPort _startWorker(Isolate runnable, SendPort replyPort) {
     var factoryName = _getJSConstructorName(runnable);
-    if (globalState.isWorker) {
-      globalState.mainWorker.postMessage(_serializeMessage({
+    if (_globalState.isWorker) {
+      _globalState.mainWorker.postMessage(_serializeMessage({
           'command': 'spawn-worker',
           'factoryName': factoryName,
           'replyPort': _serializeMessage(replyPort)}));
     } else {
       _spawnWorker(factoryName, _serializeMessage(replyPort));
     }
   }
 
   /**
    * The src url for the script tag that loaded this code. Used to create
@@ skipping 31 matching lines @@
   /** Starts a new worker with the given URL. */
   static _Worker _newWorker(url) native "return new Worker(url);";
 
   /**
    * Spawns an isolate in a worker. [factoryName] is the Javascript constructor
    * name for the isolate entry point class.
    */
   static void _spawnWorker(factoryName, serializedReplyPort) {
     final worker = _newWorker(_thisScript);
     worker.onmessage = (e) { _processWorkerMessage(worker, e); };
-    var workerId = globalState.nextWorkerId++;
+    var workerId = _globalState.nextWorkerId++;
     // We also store the id on the worker itself so that we can unregister it.
     worker.id = workerId;
-    globalState.workers[workerId] = worker;
+    _globalState.workers[workerId] = worker;
     worker.postMessage(_serializeMessage({
       'command': 'start',
       'id': workerId,
       'replyTo': serializedReplyPort,
       'factoryName': factoryName }));
   }
 
   /**
    * Assume that [e] is a browser message event and extract its message data.
    * We don't import the dom explicitly so, when workers are disabled, this
    * library can also run on top of nodejs.
    */
   static _getEventData(e) native "return e.data";
 
   /**
    * Process messages on a worker, either to control the worker instance or to
    * pass messages along to the isolate running in the worker.
    */
   static void _processWorkerMessage(sender, e) {
     var msg = _deserializeMessage(_getEventData(e));
     switch (msg['command']) {
       // TODO(sigmund): delete after we migrate to the new API
       case 'start':
-        globalState.currentWorkerId = msg['id'];
+        _globalState.currentWorkerId = msg['id'];
         var runnerObject =
             _allocate(_getJSConstructorFromName(msg['factoryName']));
         var serializedReplyTo = msg['replyTo'];
-        globalState.topEventLoop.enqueue(new IsolateContext(), function() {
+        _globalState.topEventLoop.enqueue(new _IsolateContext(), function() {
           var replyTo = _deserializeMessage(serializedReplyTo);
           _startIsolate(runnerObject, replyTo);
         }, 'worker-start');
-        globalState.topEventLoop.run();
+        _globalState.topEventLoop.run();
         break;
       case 'start2':
-        globalState.currentWorkerId = msg['id'];
+        _globalState.currentWorkerId = msg['id'];
         Function entryPoint = _getJSFunctionFromName(msg['functionName']);
         var replyTo = _deserializeMessage(msg['replyTo']);
-        globalState.topEventLoop.enqueue(new IsolateContext(), function() {
+        _globalState.topEventLoop.enqueue(new _IsolateContext(), function() {
           _startIsolate2(entryPoint, replyTo);
         }, 'worker-start');
-        globalState.topEventLoop.run();
+        _globalState.topEventLoop.run();
         break;
       // TODO(sigmund): delete after we migrate to the new API
       case 'spawn-worker':
         _spawnWorker(msg['factoryName'], msg['replyPort']);
         break;
       case 'spawn-worker2':
         _spawnWorker2(msg['functionName'], msg['uri'], msg['replyPort']);
         break;
       case 'message':
         msg['port'].send(msg['msg'], msg['replyTo']);
-        globalState.topEventLoop.run();
+        _globalState.topEventLoop.run();
         break;
       case 'close':
         _log("Closing Worker");
-        globalState.workers.remove(sender.id);
+        _globalState.workers.remove(sender.id);
         sender.terminate();
-        globalState.topEventLoop.run();
+        _globalState.topEventLoop.run();
         break;
       case 'log':
         _log(msg['msg']);
         break;
       case 'print':
-        if (globalState.isWorker) {
-          globalState.mainWorker.postMessage(
+        if (_globalState.isWorker) {
+          _globalState.mainWorker.postMessage(
               _serializeMessage({'command': 'print', 'msg': msg}));
         } else {
           print(msg['msg']);
         }
         break;
       case 'error':
         throw msg['msg'];
     }
   }
 
   /** Log a message, forwarding to the main worker if appropriate. */
   static _log(msg) {
-    if (globalState.isWorker) {
-      globalState.mainWorker.postMessage(
+    if (_globalState.isWorker) {
+      _globalState.mainWorker.postMessage(
           _serializeMessage({'command': 'log', 'msg': msg }));
     } else {
       try {
         _consoleLog(msg);
       } catch(e, trace) {
         throw new Exception(trace);
       }
     }
   }
 
@@ skipping 51 matching lines @@
       return f.name || null;
     }
   """;
 
   /** Create a new JavaScript object instance given its constructor. */
   static var _allocate(var ctor) native "return new ctor();";
 
   /** Starts a non-worker isolate. */
   static SendPort _startNonWorker(Isolate runnable, SendPort replyTo) {
     // Spawn a new isolate and create the receive port in it.
-    final spawned = new IsolateContext();
+    final spawned = new _IsolateContext();
 
     // Instead of just running the provided runnable, we create a
     // new cloned instance of it with a fresh state in the spawned
     // isolate. This way, we do not get cross-isolate references
     // through the runnable.
     final ctor = _getJSConstructor(runnable);
-    globalState.topEventLoop.enqueue(spawned, function() {
+    _globalState.topEventLoop.enqueue(spawned, function() {
       _startIsolate(_allocate(ctor), replyTo);
     }, 'nonworker start');
   }
 
   /** Given a ready-to-start runnable, start running it. */
   static void _startIsolate(Isolate isolate, SendPort replyTo) {
-    fillStatics(globalState.currentContext);
+    _fillStatics(_globalState.currentContext);
     ReceivePort port = new ReceivePort();
     replyTo.send(_SPAWNED_SIGNAL, port.toSendPort());
     isolate._run(port);
   }
 
   // TODO(sigmund): clean up above, after we make the new API the default:
 
   static _spawn2(String functionName, String uri, bool isLight) {
     Completer<SendPort> completer = new Completer<SendPort>();
     ReceivePort port = new ReceivePort.singleShot();
     port.receive((msg, SendPort replyPort) {
       assert(msg == _SPAWNED_SIGNAL);
       completer.complete(replyPort);
     });
 
     SendPort signalReply = port.toSendPort();
 
-    if (globalState.useWorkers && !isLight) {
+    if (_globalState.useWorkers && !isLight) {
       _startWorker2(functionName, uri, signalReply);
     } else {
       _startNonWorker2(functionName, uri, signalReply);
     }
     return new _BufferingSendPort(
-        globalState.currentContext.id, completer.future);
+        _globalState.currentContext.id, completer.future);
   }
 
   static SendPort _startWorker2(
       String functionName, String uri, SendPort replyPort) {
-    if (globalState.isWorker) {
-      globalState.mainWorker.postMessage(_serializeMessage({
+    if (_globalState.isWorker) {
+      _globalState.mainWorker.postMessage(_serializeMessage({
           'command': 'spawn-worker2',
           'functionName': functionName,
           'uri': uri,
           'replyPort': replyPort}));
     } else {
       _spawnWorker2(functionName, uri, replyPort);
     }
   }
 
   static SendPort _startNonWorker2(
       String functionName, String uri, SendPort replyPort) {
     // TODO(eub): support IE9 using an iframe -- Dart issue 1702.
     if (uri != null) throw new UnsupportedOperationException(
             "Currently spawnUri is not supported without web workers.");
-    globalState.topEventLoop.enqueue(new IsolateContext(), function() {
+    _globalState.topEventLoop.enqueue(new _IsolateContext(), function() {
       final func = _getJSFunctionFromName(functionName);
       _startIsolate2(func, replyPort);
     }, 'nonworker start');
   }
 
   static void _startIsolate2(Function topLevel, SendPort replyTo) {
-    fillStatics(globalState.currentContext);
+    _fillStatics(_globalState.currentContext);
     _port = new ReceivePort();
     replyTo.send(_SPAWNED_SIGNAL, port.toSendPort());
     topLevel();
   }
 
   /**
    * Spawns an isolate in a worker. [factoryName] is the Javascript constructor
    * name for the isolate entry point class.
    */
   static void _spawnWorker2(functionName, uri, replyPort) {
     if (functionName == null) functionName = 'main';
     if (uri == null) uri = _thisScript;
     if (!(new Uri.fromString(uri).isAbsolute())) {
       // The constructor of dom workers requires an absolute URL. If we use a
       // relative path we will get a DOM exception.
       String prefix = _thisScript.substring(0, _thisScript.lastIndexOf('/'));
       uri = "$prefix/$uri";
     }
     final worker = _newWorker(uri);
     worker.onmessage = (e) { _processWorkerMessage(worker, e); };
-    var workerId = globalState.nextWorkerId++;
+    var workerId = _globalState.nextWorkerId++;
     // We also store the id on the worker itself so that we can unregister it.
     worker.id = workerId;
-    globalState.workers[workerId] = worker;
+    _globalState.workers[workerId] = worker;
     worker.postMessage(_serializeMessage({
       'command': 'start2',
       'id': workerId,
       // Note: we serialize replyPort twice because the child worker needs to
       // first deserialize the worker id, before it can correctly deserialize
       // the port (port deserialization is sensitive to what is the current
       // workerId).
       'replyTo': _serializeMessage(replyPort),
       'functionName': functionName }));
   }
 }