c++ 阻塞队列的实现

#include <memory>
#include <mutex>
#include <condition_variable>
#include <queue>
#include <chrono>

namespace WPAYRTL
{
template<class T>
class BlockingQueue
{
public:
BlockingQueue() {}
~BlockingQueue() {}

void offer(std::shared_ptr<T> &e)
{
{
std::unique_lock<std::mutex> lockGard(_myMutex);
_queue.push(e);
}
_myVariable.notify_all();
}

std::shared_ptr<T> take()
{
std::unique_lock<std::mutex> lockGard(_myMutex);
_myVariable.wait(lockGard, [&] {return _queue.size() > 0;});
std::shared_ptr<T> e = _queue.front();
_queue.pop();
return e;
}

std::shared_ptr<T>take(std::chrono::milliseconds& time)
{
std::unique_lock<std::mutex> lockGard(_myMutex);
bool result = _myVariable.wait_for(lockGard, time, [&] {return _queue.size() > 0;});
if (!result)
{
return nullptr;
}
std::shared_ptr<T> e = _queue.front();
_queue.pop();
return e;
}

private:
std::queue<std::shared_ptr<T>> _queue;
std::mutex _myMutex;
std::condition_variable _myVariable;
};

}