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#ifndef INCLUDED_SLIDESHOW_ACTIVITIESQUEUE_HXX
#define INCLUDED_SLIDESHOW_ACTIVITIESQUEUE_HXX

#include <deque>

#include "activity.hxx"
#include "unoviewcontainer.hxx"

#include <canvas/elapsedtime.hxx>

#include <boost/shared_ptr.hpp>
#include <boost/utility.hpp> // for boost::noncopyable


/* Definition of ActivitiesQueue class */

namespace slideshow
{
    namespace internal
    {
		/** This class handles the XSprite updates needed for
            animations, such as moves, scales etc. You can add
            activity objects to this class, which are called in a
            round-robin fashion.
        */
        class ActivitiesQueue : private ::boost::noncopyable
        {
        public:
            /** Create an ActivitiesQueue.

            	@param pPresTimer
                Pointer to global presentation timer. Used for
                adjusting and holding global presentation time.
             */
            ActivitiesQueue(
                const ::boost::shared_ptr< ::canvas::tools::ElapsedTime >&	pPresTimer );
            ~ActivitiesQueue();

            /** Add the given activity to the queue.
             */
            bool addActivity( const ActivitySharedPtr& pActivity );

            /** Process the activities queue.

            	This method performs the smallest atomic processing
            	possible on the queue (typically, this means one
            	activity get processed).
             */
            void process();

            /** Call all dequeued activities' dequeued() method
             */
            void processDequeued();

			/** Query state of the queue

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

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

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

            /** returns number of all activities, waiting, reinserted and dequeued
             */
            std::size_t size() const
            { 
                return maCurrentActivitiesWaiting.size() + maCurrentActivitiesReinsert.size() + maDequeuedActivities.size();
            }
            
        private:
            ::boost::shared_ptr< ::canvas::tools::ElapsedTime > mpTimer;
            
            typedef ::std::deque< ActivitySharedPtr > ActivityQueue;

            ActivityQueue 			maCurrentActivitiesWaiting;  // currently running        
                                    				             // activities, that still   
				                                                 // await processing for this
                				                                 // round

            ActivityQueue 			maCurrentActivitiesReinsert; 	// currently running    
												                  	// activities, that are 
										                          	// already processed for
										                          	// this round, and wants
				            										// to be reinserted next
				            										// round

            ActivityQueue           maDequeuedActivities; // This list collects all activities which did not request
                                                          // a reinsertion. After the screen update has been
                                                          // performed, those are notified via dequeued(). This
                                                          // facilitates cleanup actions taking place _after_ the
                                                          // current frame has been displayed.
        };

    }
}
#endif /* INCLUDED_SLIDESHOW_ACTIVITIESQUEUE_HXX */