OgreWorkQueue.h

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/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#ifndef __OgreWorkQueue_H__
#define __OgreWorkQueue_H__

#include "OgrePrerequisites.h"
#include "OgreAny.h"
#include "OgreSharedPtr.h"
#include "Threading/OgreThreadHeaders.h"
#include "OgreHeaderPrefix.h"

namespace Ogre
{
    class _OgreExport WorkQueue : public UtilityAlloc
    {
    protected:
        typedef map<String, uint16>::type ChannelMap;
        ChannelMap mChannelMap;
        uint16 mNextChannel;
        OGRE_MUTEX(mChannelMapMutex);
    public:
        typedef unsigned long long int RequestID;

        class _OgreExport Request : public UtilityAlloc
        {
            friend class WorkQueue;
        protected:
            uint16 mChannel;
            uint16 mType;
            Any mData;
            uint8 mRetryCount;
            RequestID mID;
            mutable bool mAborted;

        public:
            Request(uint16 channel, uint16 rtype, const Any& rData, uint8 retry, RequestID rid);
            ~Request();
            void abortRequest() const { mAborted = true; }
            uint16 getChannel() const { return mChannel; }
            uint16 getType() const { return mType; }
            const Any& getData() const { return mData; }
            uint8 getRetryCount() const { return mRetryCount; }
            RequestID getID() const { return mID; }
            bool getAborted() const { return mAborted; }
        };

        struct _OgreExport Response : public UtilityAlloc
        {
            const Request* mRequest;
            bool mSuccess;
            String mMessages;
            Any mData;

        public:
            Response(const Request* rq, bool success, const Any& data, const String& msg = StringUtil::BLANK);
            ~Response();
            const Request* getRequest() const { return mRequest; }
            bool succeeded() const { return mSuccess; }
            const String& getMessages() const { return mMessages; }
            const Any& getData() const { return mData; }
            void abortRequest() { mRequest->abortRequest(); mData.destroy(); }
        };

        class _OgreExport RequestHandler
        {
        public:
            RequestHandler() {}
            virtual ~RequestHandler() {}

            virtual bool canHandleRequest(const Request* req, const WorkQueue* srcQ) 
            { (void)srcQ; return !req->getAborted(); }

            virtual Response* handleRequest(const Request* req, const WorkQueue* srcQ) = 0;
        };

        class _OgreExport ResponseHandler
        {
        public:
            ResponseHandler() {}
            virtual ~ResponseHandler() {}

            virtual bool canHandleResponse(const Response* res, const WorkQueue* srcQ) 
            { (void)srcQ; return !res->getRequest()->getAborted(); }

            virtual void handleResponse(const Response* res, const WorkQueue* srcQ) = 0;
        };

        WorkQueue() : mNextChannel(0) {}
        virtual ~WorkQueue() {}

        virtual void startup(bool forceRestart = true) = 0;
        virtual void addRequestHandler(uint16 channel, RequestHandler* rh) = 0;
        virtual void removeRequestHandler(uint16 channel, RequestHandler* rh) = 0;

        virtual void addResponseHandler(uint16 channel, ResponseHandler* rh) = 0;
        virtual void removeResponseHandler(uint16 channel, ResponseHandler* rh) = 0;

        virtual RequestID addRequest(uint16 channel, uint16 requestType, const Any& rData, uint8 retryCount = 0, 
            bool forceSynchronous = false, bool idleThread = false) = 0;

        virtual void abortRequest(RequestID id) = 0;

        virtual void abortRequestsByChannel(uint16 channel) = 0;

        virtual void abortPendingRequestsByChannel(uint16 channel) = 0;

        virtual void abortAllRequests() = 0;
        
        virtual void setPaused(bool pause) = 0;
        virtual bool isPaused() const = 0;

        virtual void setRequestsAccepted(bool accept) = 0;
        virtual bool getRequestsAccepted() const = 0;

        virtual void processResponses() = 0; 

        virtual unsigned long getResponseProcessingTimeLimit() const = 0;

        virtual void setResponseProcessingTimeLimit(unsigned long ms) = 0;

        virtual void shutdown() = 0;

        virtual uint16 getChannel(const String& channelName);

    };

    class _OgreExport DefaultWorkQueueBase : public WorkQueue
    {
    public:

        DefaultWorkQueueBase(const String& name = StringUtil::BLANK);
        virtual ~DefaultWorkQueueBase();
        const String& getName() const;
        virtual size_t getWorkerThreadCount() const;

        virtual void setWorkerThreadCount(size_t c);

        virtual bool getWorkersCanAccessRenderSystem() const;


        virtual void setWorkersCanAccessRenderSystem(bool access);

        virtual void _processNextRequest();

        virtual void _threadMain() = 0;

        virtual bool isShuttingDown() const { return mShuttingDown; }

        virtual void addRequestHandler(uint16 channel, RequestHandler* rh);
        virtual void removeRequestHandler(uint16 channel, RequestHandler* rh);
        virtual void addResponseHandler(uint16 channel, ResponseHandler* rh);
        virtual void removeResponseHandler(uint16 channel, ResponseHandler* rh);

        virtual RequestID addRequest(uint16 channel, uint16 requestType, const Any& rData, uint8 retryCount = 0, 
            bool forceSynchronous = false, bool idleThread = false);
        virtual void abortRequest(RequestID id);
        virtual void abortRequestsByChannel(uint16 channel);
        virtual void abortPendingRequestsByChannel(uint16 channel);
        virtual void abortAllRequests();
        virtual void setPaused(bool pause);
        virtual bool isPaused() const;
        virtual void setRequestsAccepted(bool accept);
        virtual bool getRequestsAccepted() const;
        virtual void processResponses(); 
        virtual unsigned long getResponseProcessingTimeLimit() const { return mResposeTimeLimitMS; }
        virtual void setResponseProcessingTimeLimit(unsigned long ms) { mResposeTimeLimitMS = ms; }
    protected:
        String mName;
        size_t mWorkerThreadCount;
        bool mWorkerRenderSystemAccess;
        bool mIsRunning;
        unsigned long mResposeTimeLimitMS;

        typedef deque<Request*>::type RequestQueue;
        typedef deque<Response*>::type ResponseQueue;
        RequestQueue mRequestQueue; // Guarded by mRequestMutex
        RequestQueue mProcessQueue; // Guarded by mProcessMutex
        ResponseQueue mResponseQueue; // Guarded by mResponseMutex

        struct _OgreExport WorkerFunc OGRE_THREAD_WORKER_INHERIT
        {
            DefaultWorkQueueBase* mQueue;

            WorkerFunc(DefaultWorkQueueBase* q) 
                : mQueue(q) {}

            void operator()();
            
            void operator()() const;

            void run();
        };
        WorkerFunc* mWorkerFunc;

        class _OgreExport RequestHandlerHolder : public UtilityAlloc
        {
        protected:
            OGRE_RW_MUTEX(mRWMutex);
            RequestHandler* mHandler;
        public:
            RequestHandlerHolder(RequestHandler* handler)
                : mHandler(handler) {}

            // Disconnect the handler to allow it to be destroyed
            void disconnectHandler()
            {
                // write lock - must wait for all requests to finish
                OGRE_LOCK_RW_MUTEX_WRITE(mRWMutex);
                mHandler = 0;
            }

            RequestHandler* getHandler() { return mHandler; }

            Response* handleRequest(const Request* req, const WorkQueue* srcQ)
            {
                // Read mutex so that multiple requests can be processed by the
                // same handler in parallel if required
                OGRE_LOCK_RW_MUTEX_READ(mRWMutex);
                Response* response = 0;
                if (mHandler)
                {
                    if (mHandler->canHandleRequest(req, srcQ))
                    {
                        response = mHandler->handleRequest(req, srcQ);
                    }
                }
                return response;
            }

        };
        // Hold these by shared pointer so they can be copied keeping same instance
        typedef SharedPtr<RequestHandlerHolder> RequestHandlerHolderPtr;

        typedef list<RequestHandlerHolderPtr>::type RequestHandlerList;
        typedef list<ResponseHandler*>::type ResponseHandlerList;
        typedef map<uint16, RequestHandlerList>::type RequestHandlerListByChannel;
        typedef map<uint16, ResponseHandlerList>::type ResponseHandlerListByChannel;

        RequestHandlerListByChannel mRequestHandlers;
        ResponseHandlerListByChannel mResponseHandlers;
        RequestID mRequestCount; // Guarded by mRequestMutex
        bool mPaused;
        bool mAcceptRequests;
        bool mShuttingDown;

        //NOTE: If you lock multiple mutexes at the same time, the order is important!
        // For example if threadA locks mIdleMutex first then tries to lock mProcessMutex,
        // and threadB locks mProcessMutex first, then mIdleMutex. In this case you can get livelock and the system is dead!
        //RULE: Lock mProcessMutex before other mutex, to prevent livelocks
        OGRE_MUTEX(mIdleMutex);
        OGRE_MUTEX(mRequestMutex);
        OGRE_MUTEX(mProcessMutex);
        OGRE_MUTEX(mResponseMutex);
        OGRE_RW_MUTEX(mRequestHandlerMutex);


        void processRequestResponse(Request* r, bool synchronous);
        Response* processRequest(Request* r);
        void processResponse(Response* r);
        virtual void notifyWorkers() = 0;
        void addRequestWithRID(RequestID rid, uint16 channel, uint16 requestType, const Any& rData, uint8 retryCount);
        
        RequestQueue mIdleRequestQueue; // Guarded by mIdleMutex
        bool mIdleThreadRunning; // Guarded by mIdleMutex
        Request* mIdleProcessed; // Guarded by mProcessMutex
        

        bool processIdleRequests();
    };





}

#include "OgreHeaderSuffix.h"

#endif