src/lib/platform/threads/mutex.h

   1 #pragma once
   2 /*
   3  * This file is part of the libCEC(R) library.
   4  *
   5  * libCEC(R) is Copyright (C) 2011 Pulse-Eight Limited.  All rights reserved.
   6  * libCEC(R) is an original work, containing original code.
   7  *
   8  * libCEC(R) is a trademark of Pulse-Eight Limited.
   9  *
  10  * This program is dual-licensed; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23  *
  24  *
  25  * Alternatively, you can license this library under a commercial license,
  26  * please contact Pulse-Eight Licensing for more information.
  27  *
  28  * For more information contact:
  29  * Pulse-Eight Licensing       <license@pulse-eight.com>
  30  *     http://www.pulse-eight.com/
  31  *     http://www.pulse-eight.net/
  32  */
  33
  34 namespace PLATFORM
  35 {
  36   class PreventCopy
  37   {
  38   public:
  39     inline PreventCopy(void) {}
  40     inline ~PreventCopy(void) {}
  41
  42   private:
  43     inline PreventCopy(const PreventCopy &c) { *this = c; }
  44     inline PreventCopy &operator=(const PreventCopy &c){ *this = c; return *this; }
  45   };
  46
  47   class CCondition;
  48
  49   class CMutex : public PreventCopy
  50   {
  51     friend class CCondition;
  52   public:
  53     inline CMutex(void) :
  54       m_iLockCount(0)
  55     {
  56       MutexCreate(m_mutex);
  57     }
  58
  59     inline ~CMutex(void)
  60     {
  61       Clear();
  62       MutexDelete(m_mutex);
  63     }
  64
  65     inline bool TryLock(void)
  66     {
  67       if (MutexTryLock(m_mutex))
  68       {
  69         ++m_iLockCount;
  70         return true;
  71       }
  72       return false;
  73     }
  74
  75     inline bool Lock(void)
  76     {
  77       MutexLock(m_mutex);
  78       ++m_iLockCount;
  79       return true;
  80     }
  81
  82     inline void Unlock(void)
  83     {
  84       if (Lock())
  85       {
  86         if (m_iLockCount >= 2)
  87         {
  88           --m_iLockCount;
  89           MutexUnlock(m_mutex);
  90         }
  91
  92         --m_iLockCount;
  93         MutexUnlock(m_mutex);
  94       }
  95     }
  96
  97     inline bool Clear(void)
  98     {
  99       bool bReturn(false);
 100       if (TryLock())
 101       {
 102         unsigned int iLockCount = m_iLockCount;
 103         for (unsigned int iPtr = 0; iPtr < iLockCount; iPtr++)
 104           Unlock();
 105         bReturn = true;
 106       }
 107       return bReturn;
 108     }
 109
 110   private:
 111     mutex_t               m_mutex;
 112     volatile unsigned int m_iLockCount;
 113   };
 114
 115   class CLockObject : public PreventCopy
 116   {
 117   public:
 118     inline CLockObject(CMutex &mutex, bool bClearOnExit = false) :
 119       m_mutex(mutex),
 120       m_bClearOnExit(bClearOnExit)
 121     {
 122       m_mutex.Lock();
 123     }
 124
 125     inline ~CLockObject(void)
 126     {
 127       if (m_bClearOnExit)
 128         Clear();
 129       else
 130         Unlock();
 131     }
 132
 133     inline bool TryLock(void)
 134     {
 135       return m_mutex.TryLock();
 136     }
 137
 138     inline void Unlock(void)
 139     {
 140       m_mutex.Unlock();
 141     }
 142
 143     inline bool Clear(void)
 144     {
 145       return m_mutex.Clear();
 146     }
 147
 148     inline bool Lock(void)
 149     {
 150       return m_mutex.Lock();
 151     }
 152
 153   private:
 154     CMutex &m_mutex;
 155     bool    m_bClearOnExit;
 156   };
 157
 158   class CCondition : public PreventCopy
 159   {
 160   public:
 161     inline CCondition(void)
 162     {
 163       ConditionCreate(m_condition);
 164     }
 165
 166     inline ~CCondition(void)
 167     {
 168       Broadcast();
 169       ConditionDelete(m_condition);
 170     }
 171
 172     inline void Broadcast(void)
 173     {
 174       ConditionBroadcast(m_condition);
 175     }
 176
 177     inline void Signal(void)
 178     {
 179       ConditionSignal(m_condition);
 180     }
 181
 182     inline bool Wait(CMutex &mutex, uint32_t iTimeout = 0)
 183     {
 184       return ConditionWait(m_condition, mutex.m_mutex, iTimeout);
 185     }
 186
 187     static void Sleep(uint32_t iTimeout)
 188     {
 189       CCondition w;
 190       CMutex m;
 191       CLockObject lock(m);
 192       w.Wait(m, iTimeout);
 193     }
 194
 195     condition_t m_condition;
 196   };
 197 }