Implement scheduleImmediate for the VM.

runtime/lib/isolate_patch.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.
 
 import "dart:collection" show HashMap;
 
 patch class ReceivePort {
   /* patch */ factory ReceivePort() = _ReceivePortImpl;
 
   /* patch */ factory ReceivePort.fromRawReceivePort(RawReceivePort rawPort) =
@@ skipping 39 matching lines @@
 
   close() {
     _rawPort.close();
     _controller.close();
   }
 
   final RawReceivePort _rawPort;
   StreamController _controller;
 }
 
+typedef void ImmediateCallback();
+
+/// The callback that has been registered through `scheduleImmediate`.
+ImmediateCallback _pendingImmediateCallback;
+
+/// The closure that should be used as scheduleImmediateClosure, when the VM
+/// is responsible for the event loop.
+void _isolateScheduleImmediate(void callback()) {
+  assert(_pendingImmediateCallback == null);
+  _pendingImmediateCallback = callback;
+}
+
+/// Provide closurized access to _isolateScheduleImmediate.
+/// This makes it easier for embedders to set the scheduleImmediate closure.
+Function get _isolateScheduleImmediateClosure => _isolateScheduleImmediate;

[Ivan Posva, 2013/11/27 22:08:32]

There is one too many ways to get at the closure. Please remove this as it is
more confusing than is worth. All the other embedder defined closures are of the
form _getXYZClosure().

[floitsch, 2013/11/28 19:05:54]

Dartium usually uses getters, but I should be able to adapt their code.
done.

+
+/// The embedder can execute this function to get hold of
+/// [_isolateScheduleImmediate] above.
+Function _getIsolateScheduleImmediateClosure() {
+  return _isolateScheduleImmediate;
+}
+
 class _RawReceivePortImpl implements RawReceivePort {
   factory _RawReceivePortImpl() native "RawReceivePortImpl_factory";
 
   close() {
     _portMap.remove(_id);
     _closeInternal(_id);
   }
 
   SendPort get sendPort {
     return new _SendPortImpl(_id);
@@ skipping 15 matching lines @@
 
   // Called from the VM to retrieve the RawReceivePort for a message.
   static _RawReceivePortImpl _lookupReceivePort(int id) {
     return _portMap[id];
   }
 
   // Called from the VM to dispatch to the handler.
   static void _handleMessage(
       _RawReceivePortImpl port, int replyId, var message) {
     assert(port != null);
+    // TODO(floitsch): this relies on the fact that any exception aborts the
+    // VM. Once we have non-fatal global exceptions we need to catch errors
+    // so that we can run the immediate callbacks.
     port._handler(message);
+    if (_pendingImmediateCallback != null) {
+      var callback = _pendingImmediateCallback;
+      _pendingImmediateCallback = null;
+      callback();
+    }
   }
 
   // Call into the VM to close the VM maintained mappings.
   static _closeInternal(int id) native "RawReceivePortImpl_closeInternal";
 
   void set handler(Function newHandler) {
     this._handler = newHandler;
   }
 
   final int _id;
@@ skipping 136 matching lines @@
   }
 
   static final RawReceivePort _self = _mainPort;
   static RawReceivePort get _mainPort native "Isolate_mainPort";
 
   static SendPort _spawnFunction(Function topLevelFunction)
       native "Isolate_spawnFunction";
 
   static SendPort _spawnUri(String uri) native "Isolate_spawnUri";
 }