xpcom/threads/nsIDirectTaskDispatcher.idl

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsIRunnable.idl"
   8
   9 %{C++
  10 #include "mozilla/AlreadyAddRefed.h"
  11 %}
  12
  13 native alreadyAddRefed_nsIRunnable(already_AddRefed<nsIRunnable>);
  14
  15 /*
  16  * The primary use of this interface is to allow any nsISerialEventTarget to
  17  * provide Direct Task dispatching which is similar (but not identical to) the
  18  * microtask semantics of JS promises.
  19  * New direct task may be dispatched when a current direct task is running. In
  20  * which case they will be run in FIFO order.
  21  */
  22 [uuid(e05bf0fe-94b7-4e28-8462-a8368da9c136)]
  23 interface nsIDirectTaskDispatcher : nsISupports
  24 {
  25   /**
  26    * Dispatch an event for the nsISerialEventTarget, using the direct task
  27    * queue.
  28    *
  29    * This function must be called from the same nsISerialEventTarget
  30    * implementing direct task dispatching.
  31    *
  32    * @param event
  33    *   The alreadyAddRefed<> event to dispatch.
  34    *
  35    */
  36   [noscript] void dispatchDirectTask(in alreadyAddRefed_nsIRunnable event);
  37
  38   /**
  39    * Synchronously run any pending direct tasks queued.
  40    */
  41   [noscript] void drainDirectTasks();
  42
  43   /**
  44    * Returns true if any direct tasks are pending.
  45    */
  46   [noscript] bool haveDirectTasks();
  47
  48   %{C++
  49   // Infallible version of the above. Will assert that it is successful.
  50   bool HaveDirectTasks() {
  51     bool value = false;
  52     MOZ_ALWAYS_SUCCEEDS(HaveDirectTasks(&value));
  53     return value;
  54   }
  55   %}
  56
  57 };