requestHandler.h

/* Copyright (c) 2005-2011, Stefan Eilemann <eile@equalizergraphics.com> 
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License version 2.1 as published
 * by the Free Software Foundation.
 *  
 * This library 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 Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef COBASE_REQUESTHANDLER_H
#define COBASE_REQUESTHANDLER_H

#include <co/base/api.h>       // COBASE_API definition
#include <co/base/stdExt.h>    // member
#include <co/base/thread.h>    // thread-safety macros
#include <co/base/spinLock.h>  // member
#include <co/base/timedLock.h> // member
#include <co/base/uint128_t.h> // member

#include <list>

namespace co
{
namespace base
{
    class RequestHandler : public NonCopyable
    {
    public:
        COBASE_API RequestHandler();

        COBASE_API ~RequestHandler();

        COBASE_API uint32_t registerRequest( void* data = 0 );

        COBASE_API void unregisterRequest( const uint32_t requestID );

        COBASE_API bool waitRequest( const uint32_t requestID, void*& result,
                               const uint32_t timeout = EQ_TIMEOUT_INDEFINITE );

        COBASE_API bool waitRequest( const uint32_t requestID, uint32_t& result,
                               const uint32_t timeout = EQ_TIMEOUT_INDEFINITE );
        COBASE_API bool waitRequest( const uint32_t requestID, bool& result,
                               const uint32_t timeout = EQ_TIMEOUT_INDEFINITE );
        COBASE_API bool waitRequest(const uint32_t requestID, uint128_t& result,
                               const uint32_t timeout = EQ_TIMEOUT_INDEFINITE );
        COBASE_API bool waitRequest( const uint32_t requestID );

        COBASE_API bool isRequestServed( const uint32_t requestID ) const;

        COBASE_API void* getRequestData( const uint32_t requestID );

        COBASE_API void serveRequest( const uint32_t requestID,
                                        void* result = 0 );
        COBASE_API void serveRequest( const uint32_t requestID,
                                        uint32_t result );
        COBASE_API void serveRequest( const uint32_t requestID, bool result );
        COBASE_API void serveRequest( const uint32_t requestID,
                                      const uint128_t& result );
        bool hasPendingRequests() const { return !_requests.empty( ); }

    private:
        mutable SpinLock _mutex;

        struct Request
        {
            Request() { lock.set(); }
            ~Request(){}
            
            TimedLock lock;
            void*     data;

            union Result
            {
                void*    rPointer;
                uint32_t rUint32;
                bool     rBool;
                struct
                {
                    uint64_t low;
                    uint64_t high;
                } rUint128;
            } result;
        };
        // @endcond

        typedef stde::hash_map< uint32_t, Request* > RequestHash;

        uint32_t            _requestID;
        RequestHash         _requests;
        std::list<Request*> _freeRequests;
        friend COBASE_API std::ostream& operator << (std::ostream&,
                                                     const RequestHandler&);

        bool _waitRequest( const uint32_t requestID, Request::Result& result,
                           const uint32_t timeout );

        EQ_TS_VAR( _thread );
    };

    COBASE_API std::ostream& operator << ( std::ostream&,
                                           const RequestHandler& );
}

}
#endif //COBASE_REQUESTHANDLER_H