V8 Microtask Queue & API

src/v8natives.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1871 matching lines @@
 
 SetUpFunction();
 
 
 //----------------------------------------------------------------------------
 
 // TODO(rossberg): very simple abstraction for generic microtask queue.
 // Eventually, we should move to a real event queue that allows to maintain
 // relative ordering of different kinds of tasks.
 
-RunMicrotasks.runners = new InternalArray;
+function GetMicrotaskQueue() {
+  var microtaskState = %GetMicrotaskState();
+  if (IS_UNDEFINED(microtaskState.queue)) {
+    microtaskState.queue = new InternalArray;
+  }
+  return microtaskState.queue;
+}
 
 function RunMicrotasks() {
   while (%SetMicrotaskPending(false)) {
-    for (var i in RunMicrotasks.runners) RunMicrotasks.runners[i]();
+    var microtaskState = %GetMicrotaskState();
+    if (IS_UNDEFINED(microtaskState.queue))
+      return;
+
+    var microtasks = microtaskState.queue;
+    microtaskState.queue = new InternalArray;
+
+    for (var i = 0; i < microtasks.length; i++) {
+      microtasks[i]();
+    }
   }
 }
+
+function EnqueueExternalMicrotask(fn) {
+  GetMicrotaskQueue().push(fn);
+  %SetMicrotaskPending(true);
+}