slideshow/source/inc/eventqueue.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  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 <functional>
  29 #include <queue>
  30 #include <vector>
  31
  32
  33 /* Definition of ActivitiesQueue class */
  34
  35 namespace slideshow
  36 {
  37     namespace internal
  38     {
  39         /** This class handles events in a presentation. Events are
  40             time instants where e.g. effects start.
  41          */
  42         class EventQueue
  43         {
  44         public:
  45             EventQueue(
  46                 std::shared_ptr< ::canvas::tools::ElapsedTime >
  47                 const & pPresTimer );
  48
  49             ~EventQueue();
  50
  51             EventQueue(const EventQueue&) = delete;
  52             EventQueue& operator=(const EventQueue&) = delete;
  53
  54             /** Add the given event to the queue. The event is fired
  55                 at, or shortly after, its Event::getActivationTime instant.
  56              */
  57             bool addEvent( const EventSharedPtr& event );
  58
  59             /** Add the given event to the queue. The event is fired
  60                 at, or shortly after, its Event::getActivationTime instant.
  61                 The difference to addEvent() is that events added during
  62                 process() are postponed to next process().
  63              */
  64             bool addEventForNextRound( const EventSharedPtr& event );
  65
  66             /** Another way to control the order of asynchronous event
  67                 execution.  Use this method to schedule events that are to
  68                 be executed after all regular events that have no delay,
  69                 even when they schedule new regular events without delay.
  70             */
  71             bool addEventWhenQueueIsEmpty (const EventSharedPtr& rpEvent);
  72
  73             /** Process the event queue.
  74
  75                 This method executes all events whose timeout has
  76                 expired when calling this method (i.e. all events
  77                 whose scheduled time is less or equal the current
  78                 time).
  79
  80                 Check for the next available event's timeout via
  81                 nextTimeout(), or whether the queue is empty
  82                 altogether via isEmpty().
  83              */
  84             void process();
  85
  86             /** Query state of the queue
  87
  88                 @return false, if queue is empty, true otherwise
  89              */
  90             bool isEmpty() const;
  91
  92             /** Query timeout for the topmost event in the queue.
  93
  94                 @return Timeout in seconds, until the next event is
  95                 ready. The time returned here is relative to the pres
  96                 timer (i.e. the timer specified at the EventQueue
  97                 constructor). When the queue is empty (i.e. isEmpty()
  98                 returns true), the returned value is the highest
  99                 representable double value
 100                 (::std::numeric_limits<double>::max()). If the topmost
 101                 event in the queue is already pending, the timeout
 102                 returned here will actually be negative.
 103             */
 104             double nextTimeout() const;
 105
 106             /** Remove all pending events from the queue.
 107              */
 108             void clear();
 109
 110             /** Forces an empty queue, firing all events immediately
 111                 without minding any times.
 112                 @attention do only call from event loop, this calls process_()!
 113              */
 114             void forceEmpty();
 115
 116             /** Gets the queue's timer object.
 117              */
 118             std::shared_ptr< ::canvas::tools::ElapsedTime > const &
 119             getTimer() const { return mpTimer; }
 120
 121         private:
 122             mutable ::osl::Mutex      maMutex;
 123
 124             struct EventEntry : public ::std::unary_function<EventEntry, bool>
 125             {
 126                 EventSharedPtr  pEvent;
 127                 double          nTime;
 128
 129                 bool operator<( const EventEntry& ) const; // to leverage priority_queue's default compare
 130
 131                 EventEntry( EventSharedPtr const& p, double t )
 132                     : pEvent(p), nTime(t) {}
 133             };
 134
 135             typedef ::std::priority_queue< EventEntry > ImplQueueType;
 136             ImplQueueType                   maEvents;
 137             typedef ::std::vector<EventEntry> EventEntryVector;
 138             EventEntryVector                maNextEvents;
 139             ImplQueueType                   maNextNextEvents;
 140             void process_( bool bFireAllEvents );
 141
 142             // perform timing of events via relative time
 143             // measurements. The world time starts, when the
 144             // EventQueue object is created
 145             std::shared_ptr< ::canvas::tools::ElapsedTime > mpTimer;
 146         };
 147
 148     }
 149 }
 150 #endif // INCLUDED_SLIDESHOW_SOURCE_INC_EVENTQUEUE_HXX
 151
 152 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */