RAII手法封装互斥锁

RAII手法 resource acquisition is initialization(资源获取就是初始化)

使用局部对象管理资源的技术通常称为“资源获取就是初始化”。这种通用技术依赖于构造函数和析构函数的性质以及它们与异常处理的交互作用。 

 

模板方式

template <typename Mutex>
class LockGuard
{
public:
	explicit LockGuard(Mutex& m)
		: m_(m)
	{
		m_.Lock();
	}

	~LockGuard()
	{
		m_.Unlock();
	}

private:
	LockGuard(const LockGuard&);
	LockGuard& operator=(const LockGuard&);
	Mutex& m_;
};

#include <stdio.h>
#include <pthread.h>

class MutexLock
{
public:
    MutexLock()
    {
        pthread_mutex_init(&m_mutex, NULL);
        printf("MutexLock\n");
    }

    ~MutexLock()
    {
        pthread_mutex_destroy(&m_mutex);
        printf("~MutexLock\n");
    }

    void lock()
    {
        pthread_mutex_lock(&m_mutex);
        printf("lock\n");
    }

    void unlock()
    {
        pthread_mutex_unlock(&m_mutex);
        printf("unlock\n");
    }

    pthread_mutex_t* getPthreadMutex()
    {
        return &m_mutex;
    }

private:
    MutexLock(const MutexLock&);
    MutexLock& operator= (const MutexLock&);
    
private:
    pthread_mutex_t m_mutex;
};

class MutexLockGuard
{
public:
    explicit MutexLockGuard(MutexLock& mutex) : m_mutex(mutex)
    {
        m_mutex.lock();
    }

    ~MutexLockGuard()
    {
        m_mutex.unlock();
    }
    
private:
    MutexLockGuard(const MutexLockGuard&);
    MutexLockGuard& operator= (const MutexLockGuard&);
    
private:
    MutexLock &m_mutex;
};

#define MutexLockGuard(x) \
    static_assert(false, "missing mutex guard var name")


int main(void)
{
    MutexLock lock;
    MutexLockGuard lockGuard(lock);

    printf("hello, this is lock\n");
    
    return 0;
}

编译：g++ -lpthread mutex.c

运行结果：

MutexLock

lock

hello,  this is lock

unlock

~MutexLock