libreoffice/slideshow/source/inc/eventqueue.hxx

/*************************************************************************
 *
 *  $RCSfile: eventqueue.hxx,v $
 *
 *  $Revision: 1.3 $
 *
 *  last change: $Author: vg $ $Date: 2005-03-10 13:54:47 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
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 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *  Lesser General Public License for more details.
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 *  License along with this library; if not, write to the Free Software
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 *  MA  02111-1307  USA
 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source License Version 1.1 (the "License"); You may not use this file
 *  except in compliance with the License. You may obtain a copy of the
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 ************************************************************************/

#ifndef _SLIDESHOW_EVENTQUEUE_HXX
#define _SLIDESHOW_EVENTQUEUE_HXX

#ifndef _CANVAS_ELAPSEDTIME_HXX
#include <canvas/elapsedtime.hxx>
#endif

#include <queue>
#include <event.hxx>

#include "boost/utility.hpp" // for boost::noncopyable


/* Definition of ActivitiesQueue class */

namespace presentation
{
    namespace internal
    {
        /** This class handles events in a presentation. Events are
            time instants where e.g. effects start.
         */
        class EventQueue : private ::boost::noncopyable
        {
        public:
            EventQueue(
                ::boost::shared_ptr< ::canvas::tools::ElapsedTime >
                const & pPresTimer );

            ~EventQueue();

            /** Add the given event to the queue. The event is fired
                at, or shortly after, its Event::getActivationTime instant.
             */
            bool addEvent( const EventSharedPtr& event );

            /** Process the event queue.

                This method performs the smallest atomic processing
                possible on the queue (typically, this means one event
                get processed).

                @return Timeout in seconds, until the next event is
                ready. The time returned here is relative to the pres
                timer (i.e. the timer specified at the EventQueue
                constructor). When the queue is empty (i.e. isEmpty()
                returns true), the returned value is the highest
                representable double value
                (::std::numeric_limits<double>::max()).
             */
            double process();

            /** Query state of the queue

                @return false, if queue is empty, true otherwise
             */
            bool isEmpty();

            /** Remove all pending events from the queue.
             */
            void clear();

            /** Gets the queue's timer object.
             */
            ::boost::shared_ptr< ::canvas::tools::ElapsedTime > const &
            getTimer() const { return mpTimer; }

        private:
            struct EventEntry
            {
                EventSharedPtr  pEvent;
                double          nTime;

                bool operator<( const EventEntry& ) const; // to leverage priority_queue's default compare
            };

            typedef ::std::priority_queue< EventEntry > ImplQueueType;

            ImplQueueType                   maEvents;

            // perform timing of events via relative time
            // measurements. The world time starts, when the
            // EventQueue object is created
            ::boost::shared_ptr< ::canvas::tools::ElapsedTime > mpTimer;
        };

    }
}
#endif /* _SLIDESHOW_EVENTQUEUE_HXX */