class MutexLock : boost::noncopyable//最常用的類.就是std::mutex,對應的還是lock_guard和unique_lock
{
public:
MutexLock()
: holder_(0)
{
MCHECK(pthread_mutex_init(&mutex_, NULL));
}
~MutexLock()
{
assert(holder_ == 0);
MCHECK(pthread_mutex_destroy(&mutex_));
}
// must be called when locked, i.e. for assertion
bool isLockedByThisThread() const
{
return holder_ == CurrentThread::tid();
}
void assertLocked() const
{
assert(isLockedByThisThread());
}
// internal usage
void lock()
{
MCHECK(pthread_mutex_lock(&mutex_));
assignHolder();
}
void unlock()
{
unassignHolder();
MCHECK(pthread_mutex_unlock(&mutex_));
}
pthread_mutex_t* getPthreadMutex() /* non-const */
{
return &mutex_;
}
private:
friend class Condition;
class UnassignGuard : boost::noncopyable//這個類比較有意思,
{
public:
UnassignGuard(MutexLock& owner)//在wait裏構造一個本對象,構造時將鎖的擁有者線程id置0,析構時本線程重新獲得鎖
: owner_(owner)
{
owner_.unassignHolder();
}
~UnassignGuard()
{
owner_.assignHolder();
}
private:
MutexLock& owner_;
};
void unassignHolder()
{
holder_ = 0;
}
void assignHolder()
{
holder_ = CurrentThread::tid();
}
pthread_mutex_t mutex_;
pid_t holder_;
};
// Use as a stack variable, eg.
// int Foo::size() const
// {
// MutexLockGuard lock(mutex_);
// return data_.size();
// }
class MutexLockGuard : boost::noncopyable
{
public:
explicit MutexLockGuard(MutexLock& mutex)
: mutex_(mutex)
{
mutex_.lock();
}
~MutexLockGuard()
{
mutex_.unlock();
}
private:
MutexLock& mutex_;
};
muduo庫源碼學習(base)mutex
發表評論
所有評論
還沒有人評論,想成為第一個評論的人麼? 請在上方評論欄輸入並且點擊發布.