rcpp_framework/libs/brynet/base/WaitGroup.hpp

#pragma once

#include <atomic>
#include <brynet/base/NonCopyable.hpp>
#include <chrono>
#include <condition_variable>
#include <memory>
#include <mutex>

class WaitGroup : public NonCopyable {
public:
	typedef std::shared_ptr<WaitGroup> Ptr;

	static Ptr Create() {
		struct make_shared_enabler : public WaitGroup {
		};
		return std::make_shared<make_shared_enabler>();
	}

public:
	void add(int i = 1) {
		mCounter += i;
	}

	void done() {
		mCounter--;
		mCond.notify_all();
	}

	void wait() {
		std::unique_lock<std::mutex> l(mMutex);
		mCond.wait(l, [&] {
			return mCounter <= 0;
		});
	}

	template <class Rep, class Period>
	void wait(const std::chrono::duration<Rep, Period> &timeout) {
		std::unique_lock<std::mutex> l(mMutex);
		mCond.wait_for(l, timeout, [&] {
			return mCounter <= 0;
		});
	}

private:
	WaitGroup() :
			mCounter(0) {
	}

	virtual ~WaitGroup() = default;

private:
	std::mutex mMutex;
	std::atomic<int> mCounter;
	std::condition_variable mCond;
};