granicus.if.org Git - icinga2/blob - lib/base/objectlock.hpp

   1 /******************************************************************************
   2  * Icinga 2                                                                   *
   3  * Copyright (C) 2012-2016 Icinga Development Team (https://www.icinga.org/)  *
   4  *                                                                            *
   5  * This program is free software; you can redistribute it and/or              *
   6  * modify it under the terms of the GNU General Public License                *
   7  * as published by the Free Software Foundation; either version 2             *
   8  * of the License, or (at your option) any later version.                     *
   9  *                                                                            *
  10  * This program is distributed in the hope that it will be useful,            *
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  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
  13  * GNU General Public License for more details.                               *
  14  *                                                                            *
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  16  * along with this program; if not, write to the Free Software Foundation     *
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
  18  ******************************************************************************/
  19
  20 #ifndef OBJECTLOCK_H
  21 #define OBJECTLOCK_H
  22
  23 #include "base/object.hpp"
  24
  25 #define I2MUTEX_UNLOCKED 0
  26 #define I2MUTEX_LOCKED 1
  27
  28 namespace icinga
  29 {
  30
  31 /**
  32  * A scoped lock for Objects.
  33  */
  34 struct I2_BASE_API ObjectLock {
  35 public:
  36         inline ObjectLock(void)
  37                 : m_Object(NULL), m_Locked(false)
  38         { }
  39
  40         inline ~ObjectLock(void)
  41         {
  42                 Unlock();
  43         }
  44
  45         inline ObjectLock(const Object::Ptr& object)
  46                 : m_Object(object.get()), m_Locked(false)
  47         {
  48                 if (m_Object)
  49                         Lock();
  50         }
  51
  52         inline ObjectLock(const Object *object)
  53                 : m_Object(object), m_Locked(false)
  54         {
  55                 if (m_Object)
  56                         Lock();
  57         }
  58
  59         inline static void LockMutex(const Object *object)
  60         {
  61                 unsigned int it = 0;
  62
  63 #ifdef _WIN32
  64 #       ifdef _WIN64
  65                 while (InterlockedCompareExchange64((LONGLONG *)&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED) {
  66 #       else /* _WIN64 */
  67                 while (InterlockedCompareExchange(&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED) {
  68 #       endif /* _WIN64 */
  69 #else /* _WIN32 */
  70                 while (!__sync_bool_compare_and_swap(&object->m_Mutex, I2MUTEX_UNLOCKED, I2MUTEX_LOCKED)) {
  71 #endif /* _WIN32 */
  72                         if (object->m_Mutex > I2MUTEX_LOCKED) {
  73                                 boost::recursive_mutex *mtx = reinterpret_cast<boost::recursive_mutex *>(object->m_Mutex);
  74                                 mtx->lock();
  75
  76                                 return;
  77                         }
  78
  79                         Spin(it);
  80                         it++;
  81                 }
  82
  83                 boost::recursive_mutex *mtx = new boost::recursive_mutex();
  84                 mtx->lock();
  85 #ifdef _WIN32
  86 #       ifdef _WIN64
  87                 InterlockedCompareExchange64((LONGLONG *)&object->m_Mutex, reinterpret_cast<LONGLONG>(mtx), I2MUTEX_LOCKED);
  88 #       else /* _WIN64 */
  89                 InterlockedCompareExchange(&object->m_Mutex, reinterpret_cast<LONG>(mtx), I2MUTEX_LOCKED);
  90 #       endif /* _WIN64 */
  91 #else /* _WIN32 */
  92                 __sync_bool_compare_and_swap(&object->m_Mutex, I2MUTEX_LOCKED, reinterpret_cast<uintptr_t>(mtx));
  93 #endif /* _WIN32 */
  94         }
  95
  96         inline void Lock(void)
  97         {
  98                 ASSERT(!m_Locked && m_Object != NULL);
  99
 100                 LockMutex(m_Object);
 101
 102                 m_Locked = true;
 103
 104 #ifdef I2_DEBUG
 105 #       ifdef _WIN32
 106                 InterlockedExchange(&m_Object->m_LockOwner, GetCurrentThreadId());
 107 #       else /* _WIN32 */
 108                 __sync_lock_test_and_set(&m_Object->m_LockOwner, pthread_self());
 109 #       endif /* _WIN32 */
 110 #endif /* I2_DEBUG */
 111         }
 112
 113         inline static void Spin(unsigned int it)
 114         {
 115                 if (it < 8) {
 116                         /* Do nothing. */
 117                 }
 118 #ifdef SPIN_PAUSE
 119                 else if (it < 16) {
 120                         SPIN_PAUSE();
 121                 }
 122 #endif /* SPIN_PAUSE */
 123                 else {
 124 #ifdef _WIN32
 125                         Sleep(0);
 126 #else /* _WIN32 */
 127                         sched_yield();
 128 #endif /* _WIN32 */
 129                 }
 130         }
 131
 132         inline void Unlock(void)
 133         {
 134 #ifdef I2_DEBUG
 135                 if (m_Locked) {
 136 #       ifdef _WIN32
 137                         InterlockedExchange(&m_Object->m_LockOwner, 0);
 138 #       else /* _WIN32 */
 139                         __sync_lock_release(&m_Object->m_LockOwner);
 140 #       endif /* _WIN32 */
 141                 }
 142 #endif /* I2_DEBUG */
 143
 144                 if (m_Locked) {
 145                         reinterpret_cast<boost::recursive_mutex *>(m_Object->m_Mutex)->unlock();
 146                         m_Locked = false;
 147                 }
 148         }
 149
 150 private:
 151         const Object *m_Object;
 152         bool m_Locked;
 153 };
 154
 155 }
 156
 157 #endif /* OBJECTLOCK_H */