DOOM-3-BFG/neo/idlib/Thread.cpp

/*
===========================================================================

Doom 3 BFG Edition GPL Source Code
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").  

Doom 3 BFG Edition Source Code 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, either version 3 of the License, or
(at your option) any later version.

Doom 3 BFG Edition Source Code 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 Doom 3 BFG Edition Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 BFG Edition Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 BFG Edition Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/
#pragma hdrstop
#include "precompiled.h"

/*
================================================================================================
Contains the vartious ThreadingClass implementations.
================================================================================================
*/

/*
================================================================================================

	idSysThread

================================================================================================
*/

/*
========================
idSysThread::idSysThread
========================
*/
idSysThread::idSysThread() :
		threadHandle( 0 ),
		isWorker( false ),
		isRunning( false ),
		isTerminating( false ),
		moreWorkToDo( false ),
		signalWorkerDone( true ) {
}

/*
========================
idSysThread::~idSysThread
========================
*/
idSysThread::~idSysThread() {
	StopThread( true );
	if ( threadHandle ) {
		Sys_DestroyThread( threadHandle );
	}
}

/*
========================
idSysThread::StartThread
========================
*/
bool idSysThread::StartThread( const char * name_, core_t core, xthreadPriority priority, int stackSize ) {
	if ( isRunning ) {
		return false;
	}

	name = name_;

	isTerminating = false;

	if ( threadHandle ) {
		Sys_DestroyThread( threadHandle );
	}

	threadHandle = Sys_CreateThread( (xthread_t)ThreadProc, this, priority, name, core, stackSize, false );

	isRunning = true;
	return true;
}

/*
========================
idSysThread::StartWorkerThread
========================
*/
bool idSysThread::StartWorkerThread( const char * name_, core_t core, xthreadPriority priority, int stackSize ) {
	if ( isRunning ) {
		return false;
	}

	isWorker = true;

	bool result = StartThread( name_, core, priority, stackSize );

	signalWorkerDone.Wait( idSysSignal::WAIT_INFINITE );

	return result;
}

/*
========================
idSysThread::StopThread
========================
*/
void idSysThread::StopThread( bool wait ) {
	if ( !isRunning ) {
		return;
	}
	if ( isWorker ) {
		signalMutex.Lock();
		moreWorkToDo = true;
		signalWorkerDone.Clear();
		isTerminating = true;
		signalMoreWorkToDo.Raise();
		signalMutex.Unlock();
	} else {
		isTerminating = true;
	}
	if ( wait ) {
		WaitForThread();
	}
}

/*
========================
idSysThread::WaitForThread
========================
*/
void idSysThread::WaitForThread() {
	if ( isWorker ) {
		signalWorkerDone.Wait( idSysSignal::WAIT_INFINITE );
	} else if ( isRunning ) {
		Sys_DestroyThread( threadHandle );
		threadHandle = 0;
	}
}

/*
========================
idSysThread::SignalWork
========================
*/
void idSysThread::SignalWork() {
	if ( isWorker ) {
		signalMutex.Lock();
		moreWorkToDo = true;
		signalWorkerDone.Clear();
		signalMoreWorkToDo.Raise();
		signalMutex.Unlock();
	}
}

/*
========================
idSysThread::IsWorkDone
========================
*/
bool idSysThread::IsWorkDone() {
	if ( isWorker ) {
		// a timeout of 0 will return immediately with true if signaled
		if ( signalWorkerDone.Wait( 0 ) ) {
			return true;
		}
	}
	return false;
}

/*
========================
idSysThread::ThreadProc
========================
*/
int idSysThread::ThreadProc( idSysThread * thread ) {
	int retVal = 0;

	try {
		if ( thread->isWorker ) {
			for( ; ; ) {
				thread->signalMutex.Lock();
				if ( thread->moreWorkToDo ) {
					thread->moreWorkToDo = false;
					thread->signalMoreWorkToDo.Clear();
					thread->signalMutex.Unlock();
				} else {
					thread->signalWorkerDone.Raise();
					thread->signalMutex.Unlock();
					thread->signalMoreWorkToDo.Wait( idSysSignal::WAIT_INFINITE );
					continue;
				}

				if ( thread->isTerminating ) {
					break;
				}

				retVal = thread->Run();
			}
			thread->signalWorkerDone.Raise();
		} else {
			retVal = thread->Run();
		}
	} catch ( idException & ex ) {
		idLib::Warning( "Fatal error in thread %s: %s", thread->GetName(), ex.GetError() );
		// We don't handle threads terminating unexpectedly very well, so just terminate the whole process
		_exit( 0 );
	}

	thread->isRunning = false;

	return retVal;
}

/*
========================
idSysThread::Run
========================
*/
int idSysThread::Run() {
	// The Run() is not pure virtual because on destruction of a derived class
	// the virtual function pointer will be set to NULL before the idSysThread
	// destructor actually stops the thread.
	return 0;
}

/*
================================================================================================

	test

================================================================================================
*/

/*
================================================
idMyThread test class.
================================================
*/
class idMyThread : public idSysThread {
public:
	virtual int Run() {
		// run threaded code here
		return 0;
	}
	// specify thread data here
};

/*
========================
TestThread
========================
*/
void TestThread() {
	idMyThread thread;
	thread.StartThread( "myThread", CORE_ANY );
}

/*
========================
TestWorkers
========================
*/
void TestWorkers() {
	idSysWorkerThreadGroup<idMyThread> workers( "myWorkers", 4 );
	for ( ; ; ) {
		for ( int i = 0; i < workers.GetNumThreads(); i++ ) {
			// workers.GetThread( i )-> // setup work for this thread
		}
		workers.SignalWorkAndWait();
	}
}