/**

 * vim: set ts=4 :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, as published by the

 * Free Software Foundation.

 * 

 * 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/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#ifndef _INCLUDE_SOURCEMOD_THREADER_H

#define _INCLUDE_SOURCEMOD_THREADER_H

/**

 * @file IThreader.h

 * @brief Contains platform independent routines for threading.

 */

#include <IShareSys.h>

#define SMINTERFACE_THREADER_NAME		"IThreader"

#define SMINTERFACE_THREADER_VERSION	2

namespace SourceMod

{

	/**

	 * @brief Thread creation flags

	 */

	enum ThreadFlags

	{

		Thread_Default = 0,

		/**

		 * @brief Auto-release handle on finish

		 *

		 * You are not guaranteed the handle for this is valid after

		 * calling MakeThread(), so never use it until OnTerminate is called.

		 */

		Thread_AutoRelease = 1,

		/**

		 * @brief Thread is created "suspended", meaning it is inactive until unpaused.

		 */

		Thread_CreateSuspended = 2,

	};

	/**

	 * @brief Specifies thread priority levels.

	 */

	enum ThreadPriority

	{

		ThreadPrio_Minimum = -8,

		ThreadPrio_Low = -3,

		ThreadPrio_Normal = 0,

		ThreadPrio_High = 3,

		ThreadPrio_Maximum = 8,

	};

	/**

	 * @brief The current state of a thread.

	 */

	enum ThreadState

	{

		Thread_Running = 0,

		Thread_Paused = 1,

		Thread_Done = 2,

	};

	/**

	 * @brief Thread-specific parameters.

	 */

	struct ThreadParams

	{

		/** Constructor */

		ThreadParams() : 

			flags(Thread_Default), 

			prio(ThreadPrio_Normal)

		{

		};

		ThreadFlags flags;		/**< Flags to set on the thread */

		ThreadPriority prio;	/**< Priority to set on the thread */

	};

	class IThreadCreator;

	/**

	 * @brief Describes a handle to a thread.

	 */

	class IThreadHandle

	{

	public:

		/** Virtual destructor */

		virtual ~IThreadHandle() { };

	public:

		/**

		 * @brief Pauses parent thread until this thread completes.

		 * 

		 * @return			True if successful, false otherwise.

		 */

		virtual bool WaitForThread() =0;

		/**

		 * @brief Destroys the thread handle.  This will not necessarily cancel the thread.

		 */

		virtual void DestroyThis() =0;

		/**

		 * @brief Returns the parent threader.

		 *

		 * @return			IThreadCreator that created this thread.

		 */

		virtual IThreadCreator *Parent() =0;

		/**

		 * @brief Returns the thread states.

		 *

		 * @param ptparams	Pointer to a ThreadParams buffer.

		 */

		virtual void GetParams(ThreadParams *ptparams) =0;

		/**

		 * @brief Returns the thread priority.

		 *

		 * @return			Thread priority.

		 */

		virtual ThreadPriority GetPriority() =0;

		/**

		 * @brief Sets thread priority.

		 * NOTE: On Linux, this always returns false.

		 *

		 * @param prio		Thread priority to set.

		 * @return			True if successful, false otherwise.

		 */

		virtual bool SetPriority(ThreadPriority prio) =0;

		/**

		 * @brief Returns the thread state.

		 * 

		 * @return			Current thread state.

		 */

		virtual ThreadState GetState() =0;

		/**

		 * @brief Attempts to unpause a paused thread.

		 *

		 * @return			True on success, false otherwise.

		 */

		virtual bool Unpause() =0;

	};

	/**

	 * @brief Handles a single thread's execution.

	 */

	class IThread

	{

	public:

		/** Virtual destructor */

		virtual ~IThread() { };

	public:

		/**

		 * @brief Called when the thread runs (in its own thread).

		 *

		 * @param pHandle		Pointer to the thread's handle.

		 */

		virtual void RunThread(IThreadHandle *pHandle) =0;

		/**

		 * @brief Called when the thread terminates.  This occurs inside the thread as well.

		 *

		 * @param pHandle		Pointer to the thread's handle.

		 * @param cancel		True if the thread did not finish, false otherwise.

		 */

		virtual void OnTerminate(IThreadHandle *pHandle, bool cancel) =0;

	};

	/**

	 * @brief Describes a thread creator

	 */

	class IThreadCreator

	{

	public:

		/** Virtual Destructor */

		virtual ~IThreadCreator() { };

	public:

		/**

		 * @brief Creates a basic thread.

		 *

		 * @param pThread		IThread pointer for callbacks.

		 */

		virtual void MakeThread(IThread *pThread) =0;

		/**

		 * @brief Creates a thread with specific options.

		 *

		 * @param pThread		IThread pointer for callbacks.

		 * @param flags			Flags for the thread.

		 * @return				IThreadHandle pointer (must be released).

		 */

		virtual IThreadHandle *MakeThread(IThread *pThread, ThreadFlags flags) =0;

		/**

		 * @brief Creates a thread with specific options.

		 *

		 * @param pThread		IThread pointer for callbacks.

		 * @param params		Extended options for the thread.

		 * @return				IThreadHandle pointer (must be released).

		 */

		virtual IThreadHandle *MakeThread(IThread *pThread, const ThreadParams *params) =0;

		/**

		 * @brief Returns the priority bounds.

		 * Note: On Linux, the min and max are both Thread_Normal.

		 *

		 * @param max			Stores the maximum priority level.

		 * @param min			Stores the minimum priority level.

		 */

		virtual void GetPriorityBounds(ThreadPriority &max, ThreadPriority &min) =0;

	};

	/**

	 * @brief Describes a simple locking mutex.

	 */

	class IMutex

	{

	public:

		/** Virtual Destructor */

		virtual ~IMutex() { };

	public:

		/**

		 * @brief Attempts to lock, but returns instantly.

		 *

		 * @return		True if lock was obtained, false otherwise.

		 */

		virtual bool TryLock() =0;

		/**

 		 * @brief Attempts to lock by waiting for release.

		 */

		virtual void Lock() =0;

		/**

		 * @brief Unlocks the mutex.

		 */

		virtual void Unlock() =0;

		/**

		 * @brief Destroys the mutex handle.

		 */

		virtual void DestroyThis() =0;

	};

	/**

	 * @brief Describes a simple "condition variable"/signal lock.

	 */

	class IEventSignal

	{

	public:

		/** Virtual Destructor */

		virtual ~IEventSignal() { };

	public:

		/**

		 * @brief Waits for a signal.

		 */

		virtual void Wait() =0;

		/** 

		 * @brief Triggers the signal and resets the signal after triggering.

		 */

		virtual void Signal() =0;

		/**

		 * @brief Frees the signal handle.

		 */

		virtual void DestroyThis() =0;

	};

	/**

	 * @brief Describes possible worker states

	 */

	enum WorkerState

	{

		Worker_Invalid = -3,

		Worker_Stopped = -2,

		Worker_Paused = -1,

		Worker_Running,

	};

	/**

	 * @brief This is a "worker pool."  A single thread places tasks in a queue.

	 * Each IThread is then a task, rather than its own separate thread.

	 */

	class IThreadWorker : public IThreadCreator

	{

	public:

		/** Virtual Destructor */

		virtual ~IThreadWorker()

		{

		};

	public:

		/**

		 * @brief Runs one "frame" of the worker.

		 *

		 * @return			Number of tasks processed.

		 */

		virtual unsigned int RunFrame() =0;

	public:

		/**

		 * @brief Pauses the worker.

		 *

		 * @return			True on success, false otherwise.

		 */

		virtual bool Pause() =0;

		/**

		 * @brief Unpauses the worker.

		 *

		 * @return			True on success, false otherwise.

		 */

		virtual bool Unpause() =0;

		/** 

		 * @brief Starts the worker thread.

		 *

		 * @return			True on success, false otherwise.

		 */

		virtual bool Start() =0;

		/**

		 * @brief Stops the worker thread.

		 *

		 * @param flush		If true, all remaining tasks will be cancelled.

		 *					Otherwise, the threader will wait until the queue is empty.

		 * @return			True on success, false otherwise.

		 */

		virtual bool Stop(bool flush) =0;

		/**

		 * @brief Returns the status of the worker.

		 *

		 * @param numThreads	Pointer to store number of threads in the queue.

		 * @return				State of the worker.

		 */

		virtual WorkerState GetStatus(unsigned int *numThreads) =0;

	};

	/**

	 * @brief Describes thread worker callbacks.

	 */

	class IThreadWorkerCallbacks

	{

	public:

		/**

		 * @brief Called when the worker thread is initialized.

		 *

		 * @param pWorker		Pointer to the worker.

		 */

		virtual void OnWorkerStart(IThreadWorker *pWorker)

		{

		}

		/**

		 * @brief Called when the worker thread is cleaning up.

		 *

		 * @param pWorker		Pointer to the worker.

		 */

		virtual void OnWorkerStop(IThreadWorker *pWorker)

		{

		}

	};

	/**

	 * @brief Describes a threading system

	 */

	class IThreader : public SMInterface, public IThreadCreator

	{

	public:

		virtual const char *GetInterfaceName()

		{

			return SMINTERFACE_THREADER_NAME;

		}

		virtual unsigned int GetInterfaceVersion()

		{

			return SMINTERFACE_THREADER_VERSION;

		}

		virtual bool IsVersionCompatible(unsigned int version)

		{

			if (version < 2)

			{

				return false;

			}

			return SMInterface::IsVersionCompatible(version);

		}

	public:

		/**

		 * @brief Creates a mutex (mutual exclusion lock).

		 *

		 * @return			A new IMutex pointer (must be destroyed).

		 */

		virtual IMutex *MakeMutex() =0;

		/**

		 * @brief Sleeps the calling thread for a number of milliseconds.

		 *

		 * @param ms		Millisecond count to sleep.

		 */

		virtual void ThreadSleep(unsigned int ms) =0;

		/**

		 * @brief Creates a non-signalled event.

		 *

		 * @return			A new IEventSignal pointer (must be destroyed).

		 */

		virtual IEventSignal *MakeEventSignal() =0;

		/**

		 * @brief Creates a thread worker.

		 *

		 * @param hooks		Optional pointer to callback interface.

		 * @param threaded	If true, the worker will be threaded.

		 *					If false, the worker will require manual frame execution.

		 * @return			A new IThreadWorker pointer (must be destroyed).

		 */

		virtual IThreadWorker *MakeWorker(IThreadWorkerCallbacks *hooks, bool threaded) =0;

		/**

		 * @brief Destroys an IThreadWorker pointer.

		 *

		 * @param pWorker	IThreadWorker pointer to destroy.

		 */

		virtual void DestroyWorker(IThreadWorker *pWorker) =0;

	};

};

#endif //_INCLUDE_SOURCEMOD_THREADER_H