AudioEngineWorkerThread.h

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/*
 * AudioEngineWorkerThread.h - declaration of class AudioEngineWorkerThread
 *
 * Copyright (c) 2009-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
 *
 * This file is part of LMMS - https://lmms.io
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program (see COPYING); if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301 USA.
 *
 */
 
#ifndef LMMS_AUDIO_ENGINE_WORKER_THREAD_H
#define LMMS_AUDIO_ENGINE_WORKER_THREAD_H
 
#include <QThread>
 
#include <atomic>
 
class QWaitCondition;
 
namespace lmms
{
 
class AudioEngine;
class ThreadableJob;
 
class AudioEngineWorkerThread : public QThread
{
        Q_OBJECT
public:
        // internal representation of the job queue - all functions are thread-safe
        class JobQueue
        {
        public:
                enum class OperationMode
                {
                        Static, // no jobs added while processing queue
                        Dynamic // jobs can be added while processing queue
                } ;
 
                static constexpr size_t JOB_QUEUE_SIZE = 8192;
 
                JobQueue() :
                        m_items(),
                        m_writeIndex( 0 ),
                        m_itemsDone( 0 ),
                        m_opMode( OperationMode::Static )
                {
                        std::fill(m_items, m_items + JOB_QUEUE_SIZE, nullptr);
                }
 
                void reset( OperationMode _opMode );
 
                void addJob( ThreadableJob * _job );
 
                void run();
                void wait();
 
        private:
                std::atomic<ThreadableJob*> m_items[JOB_QUEUE_SIZE];
                std::atomic_size_t m_writeIndex;
                std::atomic_size_t m_itemsDone;
                OperationMode m_opMode;
        } ;
 
 
        AudioEngineWorkerThread( AudioEngine* audioEngine );
        ~AudioEngineWorkerThread() override;
 
        virtual void quit();
 
        static void resetJobQueue( JobQueue::OperationMode _opMode =
                                                                                                        JobQueue::OperationMode::Static )
        {
                globalJobQueue.reset( _opMode );
        }
 
        static void addJob( ThreadableJob * _job )
        {
                globalJobQueue.addJob( _job );
        }
 
        // a convenient helper function allowing to pass a container with pointers
        // to ThreadableJob objects
        template<typename T>
        static void fillJobQueue( const T & _vec,
                                                        JobQueue::OperationMode _opMode = JobQueue::OperationMode::Static )
        {
                resetJobQueue( _opMode );
                for (const auto& job : _vec)
                {
                        addJob(job);
                }
        }
 
        static void startAndWaitForJobs();
 
 
private:
        void run() override;
 
        static JobQueue globalJobQueue;
        static QWaitCondition * queueReadyWaitCond;
        static QList<AudioEngineWorkerThread *> workerThreads;
 
        volatile bool m_quit;
} ;
 
} // namespace lmms
 
#endif // LMMS_AUDIO_ENGINE_WORKER_THREAD_H