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/AbstractEventQueue.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 PrioritizedEventQueue;
  24 class ThreadEventTarget;
  25
  26 // A ThreadEventQueue implements normal monitor-style synchronization over the
  27 // InnerQueueT AbstractEventQueue. It also implements PushEventQueue and
  28 // PopEventQueue for workers (see the documentation below for an explanation of
  29 // those). All threads use a ThreadEventQueue as their event queue. InnerQueueT
  30 // is a template parameter to avoid virtual dispatch overhead.
  31 template <class InnerQueueT>
  32 class ThreadEventQueue final : public SynchronizedEventQueue {
  33  public:
  34   explicit ThreadEventQueue(UniquePtr<InnerQueueT> aQueue);
  35
  36   bool PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
  37                 EventQueuePriority aPriority) final;
  38
  39   already_AddRefed<nsIRunnable> GetEvent(bool aMayWait,
  40                                          EventQueuePriority* aPriority) final;
  41   void DidRunEvent() final;
  42   bool HasPendingEvent() final;
  43   bool HasPendingHighPriorityEvents() final;
  44
  45   bool ShutdownIfNoPendingEvents() final;
  46
  47   void Disconnect(const MutexAutoLock& aProofOfLock) final {}
  48
  49   void EnableInputEventPrioritization() final;
  50   void FlushInputEventPrioritization() final;
  51   void SuspendInputEventPrioritization() final;
  52   void ResumeInputEventPrioritization() final;
  53
  54   already_AddRefed<nsISerialEventTarget> PushEventQueue() final;
  55   void PopEventQueue(nsIEventTarget* aTarget) final;
  56
  57   already_AddRefed<nsIThreadObserver> GetObserver() final;
  58   already_AddRefed<nsIThreadObserver> GetObserverOnThread() final;
  59   void SetObserver(nsIThreadObserver* aObserver) final;
  60
  61   Mutex& MutexRef() { return mLock; }
  62
  63   size_t SizeOfExcludingThis(
  64       mozilla::MallocSizeOf aMallocSizeOf) const override;
  65
  66  private:
  67   class NestedSink;
  68
  69   virtual ~ThreadEventQueue();
  70
  71   bool PutEventInternal(already_AddRefed<nsIRunnable>&& aEvent,
  72                         EventQueuePriority aPriority, NestedSink* aQueue);
  73
  74   UniquePtr<InnerQueueT> mBaseQueue;
  75
  76   struct NestedQueueItem {
  77     UniquePtr<EventQueue> mQueue;
  78     RefPtr<ThreadEventTarget> mEventTarget;
  79
  80     NestedQueueItem(UniquePtr<EventQueue> aQueue,
  81                     ThreadEventTarget* aEventTarget)
  82         : mQueue(std::move(aQueue)), mEventTarget(aEventTarget) {}
  83   };
  84
  85   nsTArray<NestedQueueItem> mNestedQueues;
  86
  87   Mutex mLock;
  88   CondVar mEventsAvailable;
  89
  90   bool mEventsAreDoomed = false;
  91   nsCOMPtr<nsIThreadObserver> mObserver;
  92 };
  93
  94 extern template class ThreadEventQueue<EventQueue>;
  95 extern template class ThreadEventQueue<PrioritizedEventQueue>;
  96
  97 };  // namespace mozilla
  98
  99 #endif  // mozilla_ThreadEventQueue_h