twain3.0/huagao/Device/BlockingQueue.h

#pragma once
#include <mutex>
#include <condition_variable>
#include <deque>


template <typename T>
class BlockingQueue
{
private:
	BlockingQueue(const BlockingQueue& rhs);
	BlockingQueue& operator =(const BlockingQueue& rhs);
	mutable std::mutex _mutex;
	std::condition_variable _condvar;
	std::deque<T> _queue;
	volatile bool isShutDown = false;
	T tRet;

public:
	BlockingQueue()
		: _mutex()
		, _condvar()
		, _queue()
	{
	}

	~BlockingQueue()
	{
		ShutDown();
	}

	void Clear()
	{
		std::lock_guard<std::mutex> lock(_mutex);
		_condvar.notify_all();
		_queue.clear();
	}

	void ShutDown()
	{
		isShutDown = true;
		_condvar.notify_all();
		_queue.clear();
	}

	bool IsShutDown()
	{
		return isShutDown;
	}

	void Put(const T task)
	{
		std::lock_guard<std::mutex> lock(_mutex);
		if (!isShutDown) {
			_queue.push_back(task);
			_condvar.notify_all();
		}
	}

	T Take()
	{
		std::unique_lock<std::mutex> lock(_mutex);
		if (_queue.size() <= 0)
			_condvar.wait(lock);

		if (isShutDown || _queue.empty())
			return tRet;

		T front(_queue.front());
		_queue.pop_front();

		return front;
	}

	size_t Size() const
	{
		std::lock_guard<std::mutex> lock(_mutex);
		return _queue.size();
	}
};