// This file is originally from Trantor - KQueue.h

// Copyright (c) 2016-2021, Tao An.  All rights reserved.

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
//   * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
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// documentation and/or other materials provided with the distribution.
//   * Neither the name of Tao An nor the names of other contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
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#pragma once
#include "core/loops/event_loop.h"
#include "core/loops/poller.h"

#if (defined(__unix__) && !defined(__linux__)) || \
		(defined(__APPLE__) && defined(__MACH__))
#define USE_KQUEUE
#include <memory>
#include <unordered_map>
#include <vector>
using EventList = std::vector<struct kevent>;
#endif

namespace trantor {
class Channel;

class KQueue : public Poller {
public:
	explicit KQueue(EventLoop *loop);
	virtual ~KQueue();
	virtual void poll(int timeoutMs, ChannelList *activeChannels) override;
	virtual void updateChannel(Channel *channel) override;
	virtual void removeChannel(Channel *channel) override;
	virtual void resetAfterFork() override;

private:
#ifdef USE_KQUEUE
	static const int kInitEventListSize = 16;
	int kqfd_;
	EventList events_;
	using ChannelMap = std::unordered_map<int, std::pair<int, Channel *> >;
	ChannelMap channels_;

	void fillActiveChannels(int numEvents, ChannelList *activeChannels) const;
	void update(Channel *channel);
#endif
};

} // namespace trantor