多线程互斥--mutex

    互斥对象有许多用途，属于最常用的内核对象之一。通常来说，它们用于保护由多个线程访问的内存块。如果多个线程要同时访问内存块，内存块中的数据就可能遭到破坏。互斥对象能够保证访问内存块的任何线程拥有对该内存块的独占访问权，这样就能够保证数据的完整性。

/*****************************************************************************
*  OpenST Basic tool library                                                 *
*  Copyright (C) 2014 Henry.Wen  [email protected]   .                     *
*                                                                            *
*  This file is part of OST.                                                 *
*                                                                            *
*  This program is free software; you can redistribute it and/or modify      *
*  it under the terms of the GNU General Public License version 3 as         *
*  published by the Free Software Foundation.                                *
*                                                                            *
*  You should have received a copy of the GNU General Public License         *
*  along with OST. If not, see <http://www.gnu.org/licenses/>.               *
*                                                                            *
*  Unless required by applicable law or agreed to in writing, software       *
*  distributed under the License is distributed on an "AS IS" BASIS,         *
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  *
*  See the License for the specific language governing permissions and       *
*  limitations under the License.                                            *
*                                                                            *
*  Author  : Henry.Wen                                                       *
*  E-Mail  : [email protected]                                             *
*  License : GNU General Public License (GPL)                                *
*  source code availability:https://github.com/henrywen2011/OST              *
*                                                                            *
*----------------------------------------------------------------------------*
*  Remark         : Description						     *
*----------------------------------------------------------------------------*
*  Change History :                                                          *
*  Date       | Version | Author        | Description                        *
*----------------------------------------------------------------------------*
*  2014/01/26 | 1.0.0.1 | Henry.Wen     | Create file                        *
*----------------------------------------------------------------------------*
*                                                                            *
*****************************************************************************/
#ifndef OST_CORE_OSTMUTEX_H
#define OST_CORE_OSTMUTEX_H

#include "OSTTypes.h"
#include "OSTPlatform.h"
#include "OSTBasicable.h"

#if (OST_PLAFORM == OST_PLATFORM_WIN32)
typedef CRITICAL_SECTION OST_MUTEX_SECTION;
#else
#include <pthread>
typedef pthread_mutex_t  OST_MUTEX_SECTION;
#endif

OST_NAMESPACE_BEGIN
/** 
* @class OSTMutex
* @brief A Mutex (mutual exclusion) is a synchronization mechanism used to control
* access to a shared resourcein a concurrent (multithreaded) scenario.
*/
class OSTMutex : public NonCopyable
{
public:
	OSTMutex(void);
	~OSTMutex(void);

	/**
	* @brief Locks the OSTMutex. Blocks if the OSTMutex is held by another thread.
	*/
	void Lock() const;

	/**
	* @brief Unlocks the mutex so that it can be acquired by other threads.
	*/
	void Unlock() const;

	/**
	* @brief Tries to lock the mutex. 
	* @return 
	*	-<em>OST_FALSE</em> if the mutex is already held by another thread
	*	-<em>OST_TRUE</em> otherwise.
	*/
	OSTBool TryLock();

	/**
	* @brief Locks the mutex. Blocks up to the given number of milliseconds
	* if the mutex is held by another thread.
	* Performance Note: On most platforms (including Windows), this member function is 
	* implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
	* On POSIX platforms that support pthread_mutex_timedlock(), this is used.
	*
	* @return
	*	- <em>OST_TRUE</em> if the mutex was successfully locked.
	*	- <em>OST_FALSE</em> otherwise.
	*/
	OSTBool TryLock(long millisecondes);
	
private:
	mutable OST_MUTEX_SECTION m_mutex;
};

/** 
* @class AutoLock
* @brief Using the AutoLock class is the preferred way to automatically
* lock and unlock a mutex.
*/
class AutoLock
{
public:
	AutoLock(const OSTMutex& mutex, OSTBool autolocked = OST_TRUE) : m_mutex(mutex), m_locked(autolocked)
	{
		if(autolocked)
		{
			m_mutex.Lock();
			m_locked = autolocked;
		}		
	};

	~AutoLock()
	{
		if(m_locked)
		{
			m_mutex.Unlock();
		}
	};

private:
	AutoLock(const AutoLock&);
	AutoLock& operator = (const AutoLock&);

private:
	const OSTMutex& m_mutex;
	OSTBool			m_locked;
};

/** 
* @class AutoUnLock
* @brief Using the AutoUnLock class is the preferred way to automatically
* lock and unlock a mutex.
*/
class AutoUnLock
{
public:
	AutoUnLock(const OSTMutex& mutex, OSTBool unlocked = OST_TRUE) : m_mutex(mutex), m_unlocked(unlocked)
	{
		if(m_unlocked)
		{
			m_mutex.Unlock();
		}
	}
	
	~AutoUnLock()
	{
		m_mutex.Lock();
	}

private:
	AutoUnLock(const AutoUnLock&);
	AutoUnLock& operator = (const AutoUnLock&);

private:
	const OSTMutex&		m_mutex;
	OSTBool				m_unlocked;
};

#define LOCK(mutex)		AutoLock	locker(mutex)
#define UNLOCK(mutex)	AutoUnLock	locker(mutex)

OST_NAMESPACE_END

#endif//OST_CORE_OSTMUTEX_H

/*****************************************************************************
*  OpenST Basic tool library                                                 *
*  Copyright (C) 2014 Henry.Wen  [email protected]   .                     *
*                                                                            *
*  This file is part of OST.                                                 *
*                                                                            *
*  This program is free software; you can redistribute it and/or modify      *
*  it under the terms of the GNU General Public License version 3 as         *
*  published by the Free Software Foundation.                                *
*                                                                            *
*  You should have received a copy of the GNU General Public License         *
*  along with OST. If not, see <http://www.gnu.org/licenses/>.               *
*                                                                            *
*  Unless required by applicable law or agreed to in writing, software       *
*  distributed under the License is distributed on an "AS IS" BASIS,         *
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  *
*  See the License for the specific language governing permissions and       *
*  limitations under the License.                                            *
*                                                                            *
*  Author  : Henry.Wen                                                       *
*  E-Mail  : [email protected]                                             *
*  License : GNU General Public License (GPL)                                *
*  source code availability:https://github.com/henrywen2011/OST              *
*                                                                            *
*----------------------------------------------------------------------------*
*  Remark         : Description						     *
*----------------------------------------------------------------------------*
*  Change History :                                                          *
*  Date       | Version | Author        | Description                        *
*----------------------------------------------------------------------------*
*  2014/01/24 | 1.0.0.1 | Henry.Wen     | Create file                        *
*----------------------------------------------------------------------------*
*                                                                            *
*****************************************************************************/
#include "OSTBaseExc.h"
#include "OSTMutex.h"

OST_NAMESPACE_BEGIN

OSTMutex::OSTMutex(void)
{
	pthread_mutexattr_t attr;
	
	if( 0 != pthread_mutexattr_init(&attr) || 0 != pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE))
		return;

	if (0 != pthread_mutex_init(&m_mutex, &attr))
	{
		pthread_mutexattr_destroy(&attr);
		throw SystemExc("cannot create mutex");
	}
	pthread_mutexattr_destroy(&attr);
}

OSTMutex::~OSTMutex(void)
{
	pthread_mutex_destroy(&m_mutex);
}

void OSTMutex::Lock() const
{
	try
	{
		pthread_mutex_lock(&m_mutex);
	}
	catch (...)
	{
		throw SystemExc("Cannot lock mutex");
	}
}

void OSTMutex::Unlock() const
{
	pthread_mutex_unlock(&m_mutex);
}

OSTBool OSTMutex::TryLock()
{
	OSTInt32 rc = pthread_mutex_trylock(&m_mutex);
	if (0 == rc)
	{
		return OST_TRUE;
	}
	else if (rc == EBUSY)
	{
		return OST_FALSE;
	}
	else
	{
		throw SystemExc("Cannot lock mutex");
	}	
}

OSTBool OSTMutex::TryLock(long millisecondes)
{
	return OST_TRUE;
}

OST_NAMESPACE_END

/*****************************************************************************
*  OpenST Basic tool library                                                 *
*  Copyright (C) 2014 Henry.Wen  [email protected]   .                     *
*                                                                            *
*  This file is part of OST.                                                 *
*                                                                            *
*  This program is free software; you can redistribute it and/or modify      *
*  it under the terms of the GNU General Public License version 3 as         *
*  published by the Free Software Foundation.                                *
*                                                                            *
*  You should have received a copy of the GNU General Public License         *
*  along with OST. If not, see <http://www.gnu.org/licenses/>.               *
*                                                                            *
*  Unless required by applicable law or agreed to in writing, software       *
*  distributed under the License is distributed on an "AS IS" BASIS,         *
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  *
*  See the License for the specific language governing permissions and       *
*  limitations under the License.                                            *
*                                                                            *
*  Author  : Henry.Wen                                                       *
*  E-Mail  : [email protected]                                             *
*  License : GNU General Public License (GPL)                                *
*  source code availability:https://github.com/henrywen2011/OST              *
*                                                                            *
*----------------------------------------------------------------------------*
*  Remark         : Description						     *
*----------------------------------------------------------------------------*
*  Change History :                                                          *
*  Date       | Version | Author        | Description                        *
*----------------------------------------------------------------------------*
*  2014/01/24 | 1.0.0.1 | Henry.Wen     | Create file                        *
*----------------------------------------------------------------------------*
*                                                                            *
*****************************************************************************/
#include "OSTBaseExc.h"
#include "OSTMutex.h"

OST_NAMESPACE_BEGIN

OSTMutex::OSTMutex(void)
{
	InitializeCriticalSectionAndSpinCount(&m_mutex, 4000);
}

OSTMutex::~OSTMutex(void)
{
	DeleteCriticalSection(&m_mutex);
}

void OSTMutex::Lock() const
{
	try
	{
		EnterCriticalSection(&m_mutex);
	}
	catch (...)
	{
		throw SystemExc("Cannot lock mutex");
	}
}

void OSTMutex::Unlock() const
{
	LeaveCriticalSection(&m_mutex);
}

OSTBool OSTMutex::TryLock()
{
	try
	{
		return (TryEnterCriticalSection(&m_mutex) != 0 ? OST_TRUE : OST_FALSE);
	}
	catch(...)
	{
	}
	throw SystemExc("Cannot lock mutex");
}

OSTBool OSTMutex::TryLock(long millisecondes)
{
	return OST_TRUE;
}

OST_NAMESPACE_END