/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2014 Attila Molnar <attilamolnar@hush.com>
 *   Copyright (C) 2013, 2017 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2012 Robby <robby@chatbelgie.be>
 *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2008 Craig Edwards <brain@inspircd.org>
 *
 * This file is part of InspIRCd.  InspIRCd is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#pragma once

#include "base.h"

/** Derive from this class to implement your own threaded sections of
 * code. Be sure to keep your code thread-safe and not prone to deadlocks
 * and race conditions if you MUST use threading!
 */
class CoreExport Thread
{
 private:
	/** Set to true when the thread is to exit
	 */
	bool ExitFlag;

	/** Opaque thread state managed by the ThreadEngine
	 */
	ThreadEngine::ThreadState state;

	/** ThreadEngine manages Thread::state
	 */
	friend class ThreadEngine;

 protected:
	/** Get thread's current exit status.
	 * (are we being asked to exit?)
	 */
	bool GetExitFlag()
	{
		return ExitFlag;
	}
 public:
	/** Set Creator to NULL at this point
	 */
	Thread() : ExitFlag(false)
	{
	}

	/** Override this method to put your actual
	 * threaded code here.
	 */
	virtual void Run() = 0;

	/** Signal the thread to exit gracefully.
	 */
	virtual void SetExitFlag();

	/** Join the thread (calls SetExitFlag and waits for exit)
	 */
	void join();
};


class CoreExport QueuedThread : public Thread
{
	ThreadQueueData queue;
 protected:
	/** Waits for an enqueue operation to complete
	 * You MUST hold the queue lock when you call this.
	 * It will be unlocked while you wait, and will be relocked
	 * before the function returns
	 */
	void WaitForQueue()
	{
		queue.Wait();
	}
 public:
	/** Lock queue.
	 */
	void LockQueue()
	{
		queue.Lock();
	}
	/** Unlock queue.
	 */
	void UnlockQueue()
	{
		queue.Unlock();
	}
	/** Unlock queue and wake up worker
	 */
	void UnlockQueueWakeup()
	{
		queue.Wakeup();
		queue.Unlock();
	}
	void SetExitFlag() CXX11_OVERRIDE
	{
		queue.Lock();
		Thread::SetExitFlag();
		queue.Wakeup();
		queue.Unlock();
	}
};

class CoreExport SocketThread : public Thread
{
	ThreadQueueData queue;
	ThreadSignalData signal;
 protected:
	/** Waits for an enqueue operation to complete
	 * You MUST hold the queue lock when you call this.
	 * It will be unlocked while you wait, and will be relocked
	 * before the function returns
	 */
	void WaitForQueue()
	{
		queue.Wait();
	}
 public:
	/** Notifies parent by making the SignalFD ready to read
	 * No requirements on locking
	 */
	void NotifyParent();
	SocketThread();
	virtual ~SocketThread();
	/** Lock queue.
	 */
	void LockQueue()
	{
		queue.Lock();
	}
	/** Unlock queue.
	 */
	void UnlockQueue()
	{
		queue.Unlock();
	}
	/** Unlock queue and send wakeup to worker
	 */
	void UnlockQueueWakeup()
	{
		queue.Wakeup();
		queue.Unlock();
	}
	void SetExitFlag() CXX11_OVERRIDE
	{
		queue.Lock();
		Thread::SetExitFlag();
		queue.Wakeup();
		queue.Unlock();
	}

	/**
	 * Called in the context of the parent thread after a notification
	 * has passed through the socket
	 */
	virtual void OnNotify() = 0;
};