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cseventq.h

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00001 /*
00002     Crystal Space 3D engine: Event Queue interface
00003     Copyright (C) 1998 by Andrew Zabolotny <bit@freya.etu.ru>
00004     Copyright (C) 2001 by Eric Sunshine <sunshine@sunshineco.com>
00005 
00006     This library is free software; you can redistribute it and/or
00007     modify it under the terms of the GNU Library General Public
00008     License as published by the Free Software Foundation; either
00009     version 2 of the License, or (at your option) any later version.
00010 
00011     This library is distributed in the hope that it will be useful,
00012     but WITHOUT ANY WARRANTY; without even the implied warranty of
00013     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014     Library General Public License for more details.
00015 
00016     You should have received a copy of the GNU Library General Public
00017     License along with this library; if not, write to the Free
00018     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00019 */
00020 
00021 #ifndef __CS_CSEVENTQ_H__
00022 #define __CS_CSEVENTQ_H__
00023 
00028 #include "csutil/csevent.h"
00029 #include "csutil/csevcord.h"
00030 #include "csutil/csvector.h"
00031 #include "csutil/evoutlet.h"
00032 #include "csutil/garray.h"
00033 #include "iutil/eventq.h"
00034 struct iObjectRegistry;
00035 
00040 #define DEF_EVENT_QUEUE_LENGTH  256
00041 
00050 class csEventQueue : public iEventQueue
00051 {
00052   friend class csEventOutlet;
00053   friend class csPoolEvent;
00054 private:
00055   struct Listener
00056   {
00057     iEventHandler* object;
00058     unsigned int trigger;
00059   };
00060   typedef csGrowingArray<Listener> ListenerVector;
00061 
00062   /*
00063    * The array of all allocated event outlets.  *NOTE* It is not the
00064    * responsibility of this class to free the contained event outlets, thus
00065    * this class does not override FreeItem().  Instead, it is the
00066    * responsibility of the caller of iEventQueue::CreateEventOutlet() to send
00067    * the outlet a DecRef() message (which, incidentally, will result in the
00068    * automatic removal of the outlet from this list if no references to the
00069    * outlet remain).
00070    */
00071   class EventOutletsVector : public csVector
00072   {
00073   public:
00074     EventOutletsVector() : csVector (16, 16) {}
00075     virtual ~EventOutletsVector () { DeleteAll(); }
00076     csEventOutlet* Get(int i)
00077       { return (csEventOutlet*)csVector::Get(i); }
00078   };
00079 
00080   // The array of all allocated event cords.
00081   class EventCordsVector : public csVector
00082   {
00083   public:
00084     EventCordsVector() : csVector (16, 16) {}
00085     virtual ~EventCordsVector() { DeleteAll(); }
00086     virtual bool FreeItem(void* p)
00087       { ((csEventCord*)p)->DecRef(); return true; }
00088     csEventCord* Get(int i)
00089       { return (csEventCord*)csVector::Get(i); }
00090     int Find(int Category, int SubCategory);
00091   };
00092 
00093   // Shared-object registry
00094   iObjectRegistry* Registry;
00095   // The queue itself
00096   volatile iEvent** EventQueue;
00097   // Queue head and tail pointers
00098   volatile size_t evqHead, evqTail;
00099   // The maximum queue length
00100   volatile size_t Length;
00101   // Protection against multiple threads accessing same event queue
00102   volatile int SpinLock;
00103   // Protection against delete while looping through the listeners.
00104   int busy_looping;
00105   /*  
00106    * If a delete happened while busy_looping is true we set the
00107    * following to true.
00108    */
00109   bool delete_occured;
00110   // Registered listeners.
00111   ListenerVector Listeners;
00112   // Array of allocated event outlets.
00113   EventOutletsVector EventOutlets;
00114   // Array of allocated event cords.
00115   EventCordsVector EventCords;
00116   // Pool of event objects
00117   csPoolEvent *EventPool;
00118 
00119   // Enlarge the queue size.
00120   void Resize(size_t iLength);
00121   // Lock the queue for modifications: NESTED CALLS TO LOCK/UNLOCK NOT ALLOWED!
00122   inline void Lock() { while (SpinLock) {} SpinLock++; }
00123   // Unlock the queue
00124   inline void Unlock() { SpinLock--; }
00125   // Find a particular listener index; return -1 if listener is not registered.
00126   int FindListener(iEventHandler*) const;
00127   // Notify listeners of CSMASK_Nothing.
00128   void Notify(iEvent&);
00129 
00130   /*
00131    * Start a loop. The purpose of this function is to protect
00132    * against modifications to the Listeners array while this array
00133    * is being processed.
00134    */
00135   void StartLoop ();
00136   // End a loop.
00137   void EndLoop ();
00138 
00139 public:
00140   SCF_DECLARE_IBASE;
00141 
00143   csEventQueue(iObjectRegistry*, size_t iLength = DEF_EVENT_QUEUE_LENGTH);
00145   virtual ~csEventQueue();
00146 
00148   virtual void Process();
00150   virtual void Dispatch(iEvent&);
00151 
00153   virtual void RegisterListener(iEventHandler*, unsigned int trigger);
00155   virtual void RemoveListener(iEventHandler*);
00160   virtual void RemoveAllListeners();
00162   virtual void ChangeListenerTrigger(iEventHandler*, unsigned int trigger);
00163 
00165   virtual csPtr<iEventOutlet> CreateEventOutlet(iEventPlug*);
00167   virtual iEventOutlet* GetEventOutlet();
00169   virtual iEventCord* GetEventCord (int Category, int Subcategory);
00170 
00172   uint32 CountPool();
00174   virtual csPtr<iEvent> CreateEvent(uint8 type);
00176   virtual void Post(iEvent*);
00178   virtual csPtr<iEvent> Get();
00180   virtual void Clear();
00182   virtual bool IsEmpty() { return evqHead == evqTail; }
00183 };
00184 
00185 #endif // __CS_CSEVENTQ_H__

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