slideshow/source/inc/eventqueue.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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  19
  20 #ifndef INCLUDED_SLIDESHOW_SOURCE_INC_EVENTQUEUE_HXX
  21 #define INCLUDED_SLIDESHOW_SOURCE_INC_EVENTQUEUE_HXX
  22
  23 #include <canvas/elapsedtime.hxx>
  24 #include <osl/mutex.hxx>
  25
  26 #include "event.hxx"
  27
  28 #include <boost/noncopyable.hpp>
  29 #include <functional>
  30 #include <queue>
  31 #include <vector>
  32
  33
  34 /* Definition of ActivitiesQueue class */
  35
  36 namespace slideshow
  37 {
  38     namespace internal
  39     {
  40         /** This class handles events in a presentation. Events are
  41             time instants where e.g. effects start.
  42          */
  43         class EventQueue : private ::boost::noncopyable
  44         {
  45         public:
  46             EventQueue(
  47                 ::boost::shared_ptr< ::canvas::tools::ElapsedTime >
  48                 const & pPresTimer );
  49
  50             ~EventQueue();
  51
  52             /** Add the given event to the queue. The event is fired
  53                 at, or shortly after, its Event::getActivationTime instant.
  54              */
  55             bool addEvent( const EventSharedPtr& event );
  56
  57             /** Add the given event to the queue. The event is fired
  58                 at, or shortly after, its Event::getActivationTime instant.
  59                 The difference to addEvent() is that events added during
  60                 process() are postponed to next process().
  61              */
  62             bool addEventForNextRound( const EventSharedPtr& event );
  63
  64             /** Another way to control the order of asynchronous event
  65                 exeqution.  Use this method to schedule events that are to
  66                 be executed after all regular events that have no delay,
  67                 even when they schedule new regular events without delay.
  68             */
  69             bool addEventWhenQueueIsEmpty (const EventSharedPtr& rpEvent);
  70
  71             /** Process the event queue.
  72
  73                 This method executes all events whose timeout has
  74                 expired when calling this method (i.e. all events
  75                 whose scheduled time is less or equal the current
  76                 time).
  77
  78                 Check for the next available event's timeout via
  79                 nextTimeout(), or whether the queue is empty
  80                 altogether via isEmpty().
  81              */
  82             void process();
  83
  84             /** Query state of the queue
  85
  86                 @return false, if queue is empty, true otherwise
  87              */
  88             bool isEmpty() const;
  89
  90             /** Query timeout for the topmost event in the queue.
  91
  92                 @return Timeout in seconds, until the next event is
  93                 ready. The time returned here is relative to the pres
  94                 timer (i.e. the timer specified at the EventQueue
  95                 constructor). When the queue is empty (i.e. isEmpty()
  96                 returns true), the returned value is the highest
  97                 representable double value
  98                 (::std::numeric_limits<double>::max()). If the topmost
  99                 event in the queue is already pending, the timeout
 100                 returned here will actually be negative.
 101             */
 102             double nextTimeout() const;
 103
 104             /** Remove all pending events from the queue.
 105              */
 106             void clear();
 107
 108             /** Forces an empty queue, firing all events immediately
 109                 without minding any times.
 110                 @attention do only call from event loop, this calls process_()!
 111              */
 112             void forceEmpty();
 113
 114             /** Gets the queue's timer object.
 115              */
 116             ::boost::shared_ptr< ::canvas::tools::ElapsedTime > const &
 117             getTimer() const { return mpTimer; }
 118
 119         private:
 120             mutable ::osl::Mutex      maMutex;
 121
 122             struct EventEntry : public ::std::unary_function<EventEntry, bool>
 123             {
 124                 EventSharedPtr  pEvent;
 125                 double          nTime;
 126
 127                 bool operator<( const EventEntry& ) const; // to leverage priority_queue's default compare
 128
 129                 EventEntry( EventSharedPtr const& p, double t )
 130                     : pEvent(p), nTime(t) {}
 131             };
 132
 133             typedef ::std::priority_queue< EventEntry > ImplQueueType;
 134             ImplQueueType                   maEvents;
 135             typedef ::std::vector<EventEntry> EventEntryVector;
 136             EventEntryVector                maNextEvents;
 137             ImplQueueType                   maNextNextEvents;
 138             void process_( bool bFireAllEvents );
 139
 140             // perform timing of events via relative time
 141             // measurements. The world time starts, when the
 142             // EventQueue object is created
 143             ::boost::shared_ptr< ::canvas::tools::ElapsedTime > mpTimer;
 144         };
 145
 146     }
 147 }
 148 #endif // INCLUDED_SLIDESHOW_SOURCE_INC_EVENTQUEUE_HXX
 149
 150 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */