src/shared/LockedQueue.h

   1 /*
   2  * Copyright (C) 2009-2010 MaNGOS <http://getmangos.com/>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #ifndef LOCKEDQUEUE_H
  20 #define LOCKEDQUEUE_H
  21
  22 #include <ace/Guard_T.h>
  23 #include <ace/Thread_Mutex.h>
  24 #include <deque>
  25 #include <assert.h>
  26 #include "Errors.h"
  27
  28 namespace ACE_Based
  29 {
  30     template <class T, class LockType, typename StorageType=std::deque<T> >
  31         class LockedQueue
  32     {
  33         //! Lock access to the queue.
  34         LockType _lock;
  35
  36         //! Storage backing the queue.
  37         StorageType _queue;
  38
  39         //! Cancellation flag.
  40         /*volatile*/ bool _canceled;
  41
  42         public:
  43
  44             //! Create a LockedQueue.
  45             LockedQueue()
  46                 : _canceled(false)
  47             {
  48             }
  49
  50             //! Destroy a LockedQueue.
  51             virtual ~LockedQueue()
  52             {
  53             }
  54
  55             //! Adds an item to the queue.
  56             void add(const T& item)
  57             {
  58                 lock();
  59
  60                 //ASSERT(!this->_canceled);
  61                 // throw Cancellation_Exception();
  62
  63                 _queue.push_back(item);
  64
  65                 unlock();
  66             }
  67
  68             //! Gets the next result in the queue, if any.
  69             bool next(T& result)
  70             {
  71                 ACE_Guard<LockType> g(this->_lock);
  72
  73                 if (_queue.empty())
  74                     return false;
  75
  76                 //ASSERT (!_queue.empty() || !this->_canceled);
  77                 // throw Cancellation_Exception();
  78
  79                 result = _queue.front();
  80                 _queue.pop_front();
  81
  82                 return true;
  83             }
  84
  85             //! Peeks at the top of the queue. Remember to unlock after use.
  86             T& peek()
  87             {
  88                 lock();
  89
  90                 T& result = _queue.front();
  91
  92                 return result;
  93             }
  94
  95             //! Cancels the queue.
  96             void cancel()
  97             {
  98                 lock();
  99
 100                 _canceled = true;
 101
 102                 unlock();
 103             }
 104
 105             //! Checks if the queue is cancelled.
 106             bool cancelled()
 107             {
 108                 ACE_Guard<LockType> g(this->_lock);
 109
 110                 return _canceled;
 111             }
 112
 113             //! Locks the queue for access.
 114             void lock()
 115             {
 116                 this->_lock.acquire();
 117             }
 118
 119             //! Unlocks the queue.
 120             void unlock()
 121             {
 122                 this->_lock.release();
 123             }
 124     };
 125 }
 126 #endif