xpcom/threads/ThreadEventQueue.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   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 #ifndef mozilla_ThreadEventQueue_h
   8 #define mozilla_ThreadEventQueue_h
   9
  10 #include "mozilla/EventQueue.h"
  11 #include "mozilla/CondVar.h"
  12 #include "mozilla/SynchronizedEventQueue.h"
  13 #include "nsCOMPtr.h"
  14 #include "nsTArray.h"
  15
  16 class nsIEventTarget;
  17 class nsISerialEventTarget;
  18 class nsIThreadObserver;
  19
  20 namespace mozilla {
  21
  22 class EventQueue;
  23 class ThreadEventTarget;
  24
  25 // A ThreadEventQueue implements normal monitor-style synchronization over the
  26 // EventQueue. It also implements PushEventQueue and PopEventQueue for workers
  27 // (see the documentation below for an explanation of those). All threads use a
  28 // ThreadEventQueue as their event queue. Although for the main thread this
  29 // simply forwards events to the TaskController.
  30 class ThreadEventQueue final : public SynchronizedEventQueue {
  31  public:
  32   explicit ThreadEventQueue(UniquePtr<EventQueue> aQueue,
  33                             bool aIsMainThread = false);
  34
  35   bool PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
  36                 EventQueuePriority aPriority) final;
  37
  38   already_AddRefed<nsIRunnable> GetEvent(
  39       bool aMayWait, mozilla::TimeDuration* aLastEventDelay = nullptr) final;
  40   bool HasPendingEvent() final;
  41
  42   bool ShutdownIfNoPendingEvents() final;
  43
  44   void Disconnect(const MutexAutoLock& aProofOfLock) final {}
  45
  46   already_AddRefed<nsISerialEventTarget> PushEventQueue() final;
  47   void PopEventQueue(nsIEventTarget* aTarget) final;
  48
  49   already_AddRefed<nsIThreadObserver> GetObserver() final;
  50   already_AddRefed<nsIThreadObserver> GetObserverOnThread() final;
  51   void SetObserver(nsIThreadObserver* aObserver) final;
  52
  53   Mutex& MutexRef() { return mLock; }
  54
  55   size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) override;
  56
  57  private:
  58   class NestedSink;
  59
  60   virtual ~ThreadEventQueue();
  61
  62   bool PutEventInternal(already_AddRefed<nsIRunnable>&& aEvent,
  63                         EventQueuePriority aPriority, NestedSink* aQueue);
  64
  65   const UniquePtr<EventQueue> mBaseQueue;
  66
  67   struct NestedQueueItem {
  68     UniquePtr<EventQueue> mQueue;
  69     RefPtr<ThreadEventTarget> mEventTarget;
  70
  71     NestedQueueItem(UniquePtr<EventQueue> aQueue,
  72                     ThreadEventTarget* aEventTarget);
  73   };
  74
  75   nsTArray<NestedQueueItem> mNestedQueues;
  76
  77   Mutex mLock;
  78   CondVar mEventsAvailable;
  79
  80   bool mEventsAreDoomed = false;
  81   nsCOMPtr<nsIThreadObserver> mObserver;
  82   bool mIsMainThread;
  83 };
  84
  85 }  // namespace mozilla
  86
  87 #endif  // mozilla_ThreadEventQueue_h