Proposal for new Isolate library.

sdk/lib/isolate/isolate.dart

Index: sdk/lib/isolate/isolate.dart
diff --git a/sdk/lib/isolate/isolate.dart b/sdk/lib/isolate/isolate.dart
index 49c0eb82b6ec79a044575f47a495bd079713d570..c9593d30015b8d3498cebb6282e5fb9630126a50 100644
--- a/sdk/lib/isolate/isolate.dart
+++ b/sdk/lib/isolate/isolate.dart
@@ -6,7 +6,20 @@ library dart.isolate;
 
 import "dart:async";
 
-part "isolate_stream.dart";
+/**
+ * Returns the initial message an isolate received.
+ *
+ * If the isolate is the main-isolate it contains the list of arguments that
+ * have been given on the command line.
+ *
+ * This getter supercedes io:Options (which is now deprecated).
+ */
+// TODO(floitsch): alternatively we could keep io:Options (or a nicer variant
+// of it). The main advantage of removing it, is that libraries/programs that
+// are otherwise server-independent could be spawned in the browser.
+// If devs use dart:io just for the arguments they can't be used in spawnUri,
+// by forcing them to use dart:isolate they would run in the browser, too.
+dynamic get isolateMessage;

[Lasse Reichstein Nielsen, 2013/08/26 08:06:06]

Another global variable.

Can we please just pass this as an argument to the function being called as
"main"?
If the isolate needs or expect arguments, it will have to have a function
expecting them, which makes sense.

 
 class IsolateSpawnException implements Exception {
   const IsolateSpawnException(String this._s);
@@ -15,41 +28,23 @@ class IsolateSpawnException implements Exception {
 }
 
 /**
- * The initial [ReceivePort] available by default for this isolate. This
- * [ReceivePort] is created automatically and it is commonly used to establish
- * the first communication between isolates (see [spawnFunction] and
- * [spawnUri]).
- */
-ReceivePort get port => _Isolate.port;
-
-/**
  * Creates and spawns an isolate that shares the same code as the current
  * isolate, but that starts from [topLevelFunction]. The [topLevelFunction]
  * argument must be a static top-level function or a static method that takes no
  * arguments. It is illegal to pass a function closure.
  *
- * When any isolate starts (even the main script of the application), a default
- * [ReceivePort] is created for it. This port is available from the top-level
- * getter [port] defined in this library.
- *
- * [spawnFunction] returns a [SendPort] derived from the child isolate's default
- * port.
- *
- * The optional [unhandledExceptionCallback] argument is invoked whenever an
- * exception inside the isolate is unhandled. It can be seen as a big
- * `try/catch` around everything that is executed inside the isolate. The
- * callback should return `true` when it was able to handled the exception.
+ * The initial [message] is stored in the global [isolateMessage] where the
+ * spawnee can access it. Usually the initial [message] contains a [SendPort] so
+ * that the spawner and spawnee can communicate with each other.
  */
-SendPort spawnFunction(void topLevelFunction(),
-    [bool unhandledExceptionCallback(IsolateUnhandledException e)])
-    => _Isolate.spawnFunction(topLevelFunction, unhandledExceptionCallback);
+void spawnFunction(void topLevelFunction(), [dynamic message]);
 
 /**
- * Creates and spawns an isolate whose code is available at [uri].  Like with
- * [spawnFunction], the child isolate will have a default [ReceivePort], and a
- * this function returns a [SendPort] derived from it.
+ * Creates and spawns an isolate whose code is available at [uri].
+ *
+ * Otherwise similar to [spawnFunction].
  */
-SendPort spawnUri(String uri) => _Isolate.spawnUri(uri);
+void spawnUri(Uri uri, [dynamic message]);

[Lasse Reichstein Nielsen, 2013/08/26 08:06:06]

Make it possible for this call to pass at least
- current working directory
- package root
and any other external configurations necessary to run a script correctly.
If nothing is passed, it should default to using the same values as this script.

 
 /**
  * [SendPort]s are created from [ReceivePort]s. Any message sent through
@@ -69,6 +64,11 @@ abstract class SendPort {
    * String), instances of [SendPort], and lists and maps whose elements are any
    * of these. List and maps are also allowed to be cyclic.
    *
+   * If, during serialization, an object of different type (then the primitive
+   * values mentioned above) is encountered, the
+   * serializer (if given) is invoked.  TODO(floitsch): specify how
+   * serialization and deserialization should work.
+   *
    * In the special circumstances when two isolates share the same code and are
    * running in the same process (e.g. isolates created via [spawnFunction]), it
    * is also possible to send object instances (which would be copied in the
@@ -79,7 +79,12 @@ abstract class SendPort {
    * message. Previously they were translated to the corresponding send port
    * before being transmitted.
    */
-  void send(var message, [SendPort replyTo]);
+  // We could allow a named deserializer argument which must be a global
+  // function (just like for spawnFunction) and could be transmitted (again,
+  // like for spawnFunction). This way the receiver wouldn't need to know
+  // how to deserialize.
+  // void send(var message, { serializer(x), deserializer(x), SendPort replyTo });
+  void send(var message, { serializer(x), SendPort replyTo });
 
   /**
    * Sends a message to this send port and returns a [Future] of the reply.
@@ -87,6 +92,9 @@ abstract class SendPort {
    * message to this send port with replyTo set to such receive port, and, when
    * a reply is received, it closes the receive port and completes the returned
    * future.
+   *
+   * Note: it is not possible to provide a serializer to this function. Use
+   * [send] instead.
    */
   Future call(var message);
 
@@ -118,14 +126,17 @@ abstract class ReceivePort {
   /**
    * Opens a long-lived port for receiving messages. The returned port
    * must be explicitly closed through [ReceivePort.close].
+   *
+   * If a message was serialized during sending the deserializer is invoked
+   * when receiving data.
    */
-  external factory ReceivePort();
+  external factory ReceivePort({ deserializer(x) });
 
   /**
    * Sets up a callback function for receiving pending or future
    * messages on this receive port.
    */
-  void receive(void callback(var message, SendPort replyTo));
+  void onData(void callback(var message, SendPort replyTo));
 
   /**
    * Closes this receive port immediately. Pending messages will not