Support asynchronuous spawnDomFunction.

samples/isolate_html/isolate_sample.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.
 
 library isolate_sample;
 
 import 'dart:html';
 import 'dart:isolate';
 
 /*
  * This is a simple sample application showing how to create two isolates
  * and send messages to them, and receive replies back.
  */
 
 /**
  * These are the messages we are going to send to the isolates that we create.
  */
 class MessageId {
   static const INIT = 'init';
   static const GREETING = 'greeting';
 }
 
 /**
  * Create a new isolate with a given name.  (In this sample app
  * we only have two isolates, and they are named 'A' and 'B').
  * Note, isolates aren't normally named, but it's useful to give
  * them names in this app so we can show which isolate is doing
  * what.
  */
-SendPort createIsolate(String name) {
-  var sendPort = spawnDomFunction(isolateMain);
-  var message = {
-    'id' : MessageId.INIT,
-    'args' : [name, port.toSendPort()]
-  };
-  sendPort.send(message, null);
-  return sendPort;
+Future<SendPort> createIsolate(String name) {
+  return spawnDomFunction(isolateMain).transform((sendPort) {

[vsm, 2013/03/26 19:13:37]

transform -> then? 

[Anton Muhin, 2013/03/26 19:15:37]

I have to return a future as well, hence I used transform.  Is there a way to
use .then here?

[vsm, 2013/03/26 19:21:39]

Future.then returns a Future.  I don't see transform defined on Future.

On 2013/03/26 19:15:37, Anton Muhin wrote:

[Anton Muhin, 2013/03/27 08:41:46]

You're absolutely right, sorry, got confused.

On 2013/03/26 19:21:39, vsm wrote:

+    var message = {
+      'id' : MessageId.INIT,
+      'args' : [name, port.toSendPort()]
+    };
+    sendPort.send(message, null);
+    return sendPort;
+  });
 }
 
 // TODO(mattsh) get this off the System object once it's available
 // see http://dartbug.com/3357
 bool isVm() => 1234567890123456789 % 2 > 0;
 
 /**
  * This function will run in a separate isolate, which shares almost
  * no state with the main isolate. They will both run in the main
  * UI thread, though, so that they can share DOM state.
@@ skipping 48 matching lines @@
 main() {
   //Map from isolate name to the port used to send messages to that isolate.
   final Map<String, SendPort> ports = new Map();
 
   // Do initialization and set up event handlers.
   query('#appTitle').text = 'Hello, isolates.';
   query('#vmStatus').text = '${isVm()}';
 
   var replyElement = query('.isolateMain .replyText');
 
-  ports['A'] = createIsolate('A');
-  ports['B'] = createIsolate('B');
+  createIsolate('A').then((sendPortA) {
+    ports['A'] = sendPortA;
+    createIsolate('B').then((sendPortB) {
+      ports['B'] = sendPortB;
 
-  for (var element in queryAll('.sendButton')) {
-    element.onClick.listen((Event e) {
-      replyElement.text = 'waiting for reply...';
+      for (var element in queryAll('.sendButton')) {
+        element.onClick.listen((Event e) {
+          replyElement.text = 'waiting for reply...';
 
-      var isolateName =
-          (e.currentTarget as Element).attributes['data-isolate-name'];
-      var greeting = query('input#greetingText').value;
-      var message = {'id': MessageId.GREETING, 'args': [greeting]};
-      ports[isolateName].call(message).then((var msg) {
-        replyElement.text = msg;
+          var isolateName =
+              (e.currentTarget as Element).attributes['data-isolate-name'];
+          var greeting = query('input#greetingText').value;
+          var message = {'id': MessageId.GREETING, 'args': [greeting]};
+          ports[isolateName].call(message).then((var msg) {
+            replyElement.text = msg;
+          });
+        });
+      }
+
+      port.receive((var message, SendPort replyTo) {
+        replyElement.text = message;
       });
     });
-  }
-
-  port.receive((var message, SendPort replyTo) {
-    replyElement.text = message;
   });
 }