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;
};

}