michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=8 sts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef MediaTaskQueue_h_
michael@0: #define MediaTaskQueue_h_
michael@0: 
michael@0: #include <queue>
michael@0: #include "mozilla/RefPtr.h"
michael@0: #include "mozilla/Monitor.h"
michael@0: #include "nsThreadUtils.h"
michael@0: 
michael@0: class nsIRunnable;
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: class SharedThreadPool;
michael@0: 
michael@0: // Abstracts executing runnables in order in a thread pool. The runnables
michael@0: // dispatched to the MediaTaskQueue will be executed in the order in which
michael@0: // they're received, and are guaranteed to not be executed concurrently.
michael@0: // They may be executed on different threads, and a memory barrier is used
michael@0: // to make this threadsafe for objects that aren't already threadsafe.
michael@0: class MediaTaskQueue MOZ_FINAL {
michael@0:   ~MediaTaskQueue();
michael@0: 
michael@0: public:
michael@0:   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaTaskQueue)
michael@0: 
michael@0:   MediaTaskQueue(TemporaryRef<SharedThreadPool> aPool);
michael@0: 
michael@0:   nsresult Dispatch(TemporaryRef<nsIRunnable> aRunnable);
michael@0: 
michael@0:   // Removes all pending tasks from the task queue, and blocks until
michael@0:   // the currently running task (if any) finishes.
michael@0:   void Flush();
michael@0: 
michael@0:   // Blocks until all tasks finish executing, then shuts down the task queue
michael@0:   // and exits.
michael@0:   void Shutdown();
michael@0: 
michael@0:   // Blocks until all task finish executing.
michael@0:   void AwaitIdle();
michael@0: 
michael@0:   bool IsEmpty();
michael@0: 
michael@0:   // Returns true if the current thread is currently running a Runnable in
michael@0:   // the task queue. This is for debugging/validation purposes only.
michael@0:   bool IsCurrentThreadIn();
michael@0: 
michael@0: private:
michael@0: 
michael@0:   // Blocks until all task finish executing. Called internally by methods
michael@0:   // that need to wait until the task queue is idle.
michael@0:   // mQueueMonitor must be held.
michael@0:   void AwaitIdleLocked();
michael@0: 
michael@0:   RefPtr<SharedThreadPool> mPool;
michael@0: 
michael@0:   // Monitor that protects the queue and mIsRunning;
michael@0:   Monitor mQueueMonitor;
michael@0: 
michael@0:   // Queue of tasks to run.
michael@0:   std::queue<RefPtr<nsIRunnable>> mTasks;
michael@0: 
michael@0:   // The thread currently running the task queue. We store a reference
michael@0:   // to this so that IsCurrentThreadIn() can tell if the current thread
michael@0:   // is the thread currently running in the task queue.
michael@0:   RefPtr<nsIThread> mRunningThread;
michael@0: 
michael@0:   // True if we've dispatched an event to the pool to execute events from
michael@0:   // the queue.
michael@0:   bool mIsRunning;
michael@0: 
michael@0:   // True if we've started our shutdown process.
michael@0:   bool mIsShutdown;
michael@0: 
michael@0:   class Runner : public nsRunnable {
michael@0:   public:
michael@0:     Runner(MediaTaskQueue* aQueue)
michael@0:       : mQueue(aQueue)
michael@0:     {
michael@0:     }
michael@0:     NS_METHOD Run() MOZ_OVERRIDE;
michael@0:   private:
michael@0:     RefPtr<MediaTaskQueue> mQueue;
michael@0:   };
michael@0: };
michael@0: 
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // MediaTaskQueue_h_