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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/evoutlet.h"
00031 #include "csutil/garray.h"
00032 #include "csutil/refarr.h"
00033 #include "iutil/eventq.h"
00034 
00035 struct iObjectRegistry;
00036 
00041 #define DEF_EVENT_QUEUE_LENGTH  256
00042 
00051 class csEventQueue : public iEventQueue
00052 {
00053   friend class csEventOutlet;
00054   friend class csPoolEvent;
00055 
00056 private:
00057   struct Listener
00058   {
00059     iEventHandler* object;
00060     unsigned int trigger;
00061   };
00062   typedef csDirtyAccessArray<Listener> ListenerVector;
00063 
00064   int EventCordsFind (int cat, int subcat);
00065 
00066   // Shared-object registry
00067   iObjectRegistry* Registry;
00068   // The queue itself
00069   volatile iEvent** EventQueue;
00070   // Queue head and tail pointers
00071   volatile size_t evqHead, evqTail;
00072   // The maximum queue length
00073   volatile size_t Length;
00074   // Protection against multiple threads accessing same event queue
00075   volatile int SpinLock;
00076   // Protection against delete while looping through the listeners.
00077   int busy_looping;
00078   /*  
00079    * If a delete happened while busy_looping is true we set the
00080    * following to true.
00081    */
00082   bool delete_occured;
00083   // Registered listeners.
00084   ListenerVector Listeners;
00085   // Array of allocated event outlets.
00086   csArray<csEventOutlet*> EventOutlets;
00087   // Array of allocated event cords.
00088   csRefArray<csEventCord> EventCords;
00089   // Pool of event objects
00090   csPoolEvent *EventPool;
00091 
00092   // Enlarge the queue size.
00093   void Resize (size_t iLength);
00094   // Lock the queue for modifications: NESTED CALLS TO LOCK/UNLOCK NOT ALLOWED!
00095   inline void Lock () { while (SpinLock) {} SpinLock++; }
00096   // Unlock the queue
00097   inline void Unlock () { SpinLock--; }
00098   // Find a particular listener index; return -1 if listener is not registered.
00099   int FindListener (iEventHandler*) const;
00100   // Notify listeners of CSMASK_Nothing.
00101   void Notify (iEvent&);
00102 
00103   /*
00104    * Start a loop. The purpose of this function is to protect
00105    * against modifications to the Listeners array while this array
00106    * is being processed.
00107    */
00108   void StartLoop ();
00109   // End a loop.
00110   void EndLoop ();
00111 
00112 public:
00113   SCF_DECLARE_IBASE;
00114 
00116   csEventQueue (iObjectRegistry*, size_t iLength = DEF_EVENT_QUEUE_LENGTH);
00118   virtual ~csEventQueue ();
00119 
00121   virtual void Process ();
00123   virtual void Dispatch (iEvent&);
00124 
00126   virtual void RegisterListener (iEventHandler*, unsigned int trigger);
00128   virtual void RemoveListener (iEventHandler*);
00133   virtual void RemoveAllListeners ();
00135   virtual void ChangeListenerTrigger (iEventHandler*, unsigned int trigger);
00136 
00138   virtual csPtr<iEventOutlet> CreateEventOutlet (iEventPlug*);
00140   virtual iEventOutlet* GetEventOutlet ();
00142   virtual iEventCord* GetEventCord (int Category, int Subcategory);
00143 
00145   uint32 CountPool ();
00147   virtual csPtr<iEvent> CreateEvent (uint8 type);
00149   virtual void Post (iEvent*);
00151   virtual csPtr<iEvent> Get ();
00153   virtual void Clear ();
00155   virtual bool IsEmpty () { return evqHead == evqTail; }
00156 };
00157 
00158 #endif // __CS_CSEVENTQ_H__

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