/*
 * synergy -- mouse and keyboard sharing utility
 * Copyright (C) 2002 Chris Schoeneman
 * Copyright (C) 2006 Knut St. Osmundsen
 * 
 * This package is free software you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file COPYING that should have accompanied this file.
 * 
 * This package 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.
 */

#include "CArchMultithreadOS2.h"
#include "CArch.h"
#include "XArch.h"
#include <process.h>

//
// note -- implementation of condition variable taken from:
//   http://www.cs.wustl.edu/~schmidt/win32-cv-1.html
// titled "Strategies for Implementing POSIX Condition Variables
// on Win32."  it also provides an implementation that doesn't
// suffer from the incorrectness problem described in our
// corresponding header but it is slower, still unfair, and
// can cause busy waiting.
//

//
// CArchThreadImpl
//

class CArchThreadImpl {
public:
	CArchThreadImpl();
	~CArchThreadImpl();

public:
	int					m_refCount;
	int					m_id;
	IArchMultithread::ThreadFunc	m_func;
	void*				m_userData;
	HEV					m_cancel;
	bool				m_cancelling;
	HEV					m_exit;
	void*				m_result;
	void*				m_networkData;
};

CArchThreadImpl::CArchThreadImpl() :
	m_refCount(1),
	m_id(0),
	m_func(NULL),
	m_userData(NULL),
	m_cancel(NULLHANDLE),
	m_cancelling(false),
    m_exit(NULLHANDLE),
	m_result(NULL),
	m_networkData(NULL)
{
	APIRET rc = DosCreateEventSem(NULL, &m_exit, 0, FALSE);
	assert(rc == NO_ERROR);
	rc = DosCreateEventSem(NULL, &m_cancel, 0, FALSE);
	assert(rc == NO_ERROR);
}

CArchThreadImpl::~CArchThreadImpl()
{
	DosCloseEventSem(m_exit);
	DosCloseEventSem(m_cancel);
}


//
// CArchMultithreadWindows
//

CArchMultithreadOS2*	CArchMultithreadOS2::s_instance = NULL;

CArchMultithreadOS2::CArchMultithreadOS2()
{
	assert(s_instance == NULL);
	s_instance = this;

	// no signal handlers
	for (size_t i = 0; i < kNUM_SIGNALS; ++i) {
		m_signalFunc[i]     = NULL;
		m_signalUserData[i] = NULL;
	}

	// create mutex for thread list
	m_threadMutex = newMutex();

	// create thread for calling (main) thread and add it to our
	// list.  no need to lock the mutex since we're the only thread.
	m_mainThread           = new CArchThreadImpl;
	m_mainThread->m_id     = _gettid();
	insert(m_mainThread);
}

CArchMultithreadOS2::~CArchMultithreadOS2()
{
	s_instance = NULL;

	// clean up thread list
	for (CThreadList::iterator index  = m_threadList.begin();
							   index != m_threadList.end(); ++index) {
		delete *index;
	}

	// done with mutex
	delete m_threadMutex;
}

void
CArchMultithreadOS2::setNetworkDataForCurrentThread(void* data)
{
	lockMutex(m_threadMutex);
	CArchThreadImpl* thread = findNoRef(_gettid());
	thread->m_networkData = data;
	unlockMutex(m_threadMutex);
}

void*
CArchMultithreadOS2::getNetworkDataForThread(CArchThread thread)
{
	lockMutex(m_threadMutex);
	void* data = thread->m_networkData;
	unlockMutex(m_threadMutex);
	return data;
}

HEV
CArchMultithreadOS2::getCancelEventForCurrentThread()
{
	lockMutex(m_threadMutex);
	CArchThreadImpl* thread = findNoRef(_gettid());
	unlockMutex(m_threadMutex);
	return thread->m_cancel;
}

CArchMultithreadOS2*
CArchMultithreadOS2::getInstance()
{
	return s_instance;
}

CArchCond
CArchMultithreadOS2::newCondVar()
{
	CArchCondImpl* cond                       = new CArchCondImpl;
	APIRET rc = DosCreateEventSem(NULL, &cond->m_events[CArchCondImpl::kSignal], /*DCE_AUTORESET*/0, FALSE);
	assert(rc == NO_ERROR);
	rc = DosCreateEventSem(NULL, &cond->m_events[CArchCondImpl::kBroadcast], 0, FALSE);
	assert(rc == NO_ERROR);
	cond->m_waitCountMutex                    = newMutex();
	cond->m_waitCount                         = 0;
	return cond;
}

void
CArchMultithreadOS2::closeCondVar(CArchCond cond)
{
	DosCloseEventSem(cond->m_events[CArchCondImpl::kSignal]);
	DosCloseEventSem(cond->m_events[CArchCondImpl::kBroadcast]);
	closeMutex(cond->m_waitCountMutex);
	delete cond;
}

void
CArchMultithreadOS2::signalCondVar(CArchCond cond)
{
	// is anybody waiting?
	lockMutex(cond->m_waitCountMutex);
	if (cond->m_waitCount > 0)
		DosPostEventSem(cond->m_events[CArchCondImpl::kSignal]);
	unlockMutex(cond->m_waitCountMutex);
}

void
CArchMultithreadOS2::broadcastCondVar(CArchCond cond)
{
	// is anybody waiting?
	lockMutex(cond->m_waitCountMutex);
	if (cond->m_waitCount > 0)
		DosPostEventSem(cond->m_events[CArchCondImpl::kBroadcast]);
	unlockMutex(cond->m_waitCountMutex);
}

bool
CArchMultithreadOS2::waitCondVar(CArchCond cond,
							CArchMutex mutex, double timeout)
{
	// prepare to wait
	const ULONG os2Timeout = (timeout < 0.0) ? SEM_INDEFINITE_WAIT :
								static_cast<ULONG>(1000.0 * timeout);

	// make a list of the condition variable events and the cancel event
	// for the current thread.
	SEMRECORD handles[3];
	handles[0].hsemCur = (HSEM)cond->m_events[CArchCondImpl::kSignal];
	handles[0].ulUser = 0;
	handles[1].hsemCur = (HSEM)cond->m_events[CArchCondImpl::kBroadcast];
	handles[1].ulUser = 1;
	handles[2].hsemCur = (HSEM)getCancelEventForCurrentThread();
	handles[2].ulUser = 2;
	HMUX hmux = NULLHANDLE;
	APIRET rc = DosCreateMuxWaitSem(NULL, &hmux, 3, &handles[0], DCMW_WAIT_ANY);
	if (rc != NO_ERROR) {
	    assert(rc == NO_ERROR);
	    return false;
	}


	// update waiter count
	lockMutex(cond->m_waitCountMutex);
	++cond->m_waitCount;
	unlockMutex(cond->m_waitCountMutex);

	// release mutex.  this should be atomic with the wait so that it's
	// impossible for another thread to signal us between the unlock and
	// the wait, which would lead to a lost signal on broadcasts.
	// however, we're using a manual reset event for broadcasts which
	// stays set until we reset it, so we don't lose the broadcast.
	unlockMutex(mutex);

	// wait for a signal or broadcast
    // we're using a a manual reset semaphore, that complicates matters.
	ULONG iSem = ~0UL;
    for (;;) {
	    rc = DosWaitMuxWaitSem(hmux, os2Timeout, &iSem);
        lockMutex(cond->m_waitCountMutex);
        if (rc != NO_ERROR) {
            iSem = ~0UL;
            break;
        }

        // cancel takes priority
        if (   iSem != 2
            && DosWaitEventSem((HEV)handles[2].hsemCur, 0) == NO_ERROR)
            iSem = 2;
        
        // see if we got here first.
        if (iSem != 0)
            break;
        ULONG cPosts = 0;
        rc = DosResetEventSem((HEV)handles[0].hsemCur, &cPosts);
        if (rc == NO_ERROR && cPosts > 0) {
            while (--cPosts > 0)
                DosPostEventSem((HEV)handles[0].hsemCur);
            break;
        }
    }
	DosCloseMuxWaitSem(hmux);

	// update the waiter count and reset the broadcast event if we're the last waiter
	if ((iSem == 1 && cond->m_waitCount == 0)) {
		ULONG ulIgnore;
		DosResetEventSem(cond->m_events[CArchCondImpl::kBroadcast], &ulIgnore);
	}
	unlockMutex(cond->m_waitCountMutex);

	// reacquire the mutex
	lockMutex(mutex);

	// cancel thread if necessary
	if (iSem == 2) {
		ARCH->testCancelThread();
	}

	// return success or failure
	return (rc == NO_ERROR && (iSem == 0 || iSem == 1));
}

CArchMutex
CArchMultithreadOS2::newMutex()
{
	CArchMutexImpl* mutex = new CArchMutexImpl;
	_fmutex_create2(&mutex->m_mutex, 0, __FUNCTION__);
	return mutex;
}

void
CArchMultithreadOS2::closeMutex(CArchMutex mutex)
{
	_fmutex_close(&mutex->m_mutex);
	delete mutex;
}

void
CArchMultithreadOS2::lockMutex(CArchMutex mutex)
{
	_fmutex_request(&mutex->m_mutex, 0);
}

void
CArchMultithreadOS2::unlockMutex(CArchMutex mutex)
{
	_fmutex_release(&mutex->m_mutex);
}

CArchThread
CArchMultithreadOS2::newThread(ThreadFunc func, void* data)
{
	lockMutex(m_threadMutex);

	// create thread impl for new thread
	CArchThreadImpl* thread = new CArchThreadImpl;
	thread->m_func          = func;
	thread->m_userData      = data;

	// create thread
	thread->m_id = _beginthread(threadFunc, NULL, 256*1024, thread);

	// check if thread was started
	if (thread->m_id < 0) {
		// failed to start thread so clean up
		delete thread;
		thread = NULL;
	}
	else {
		// add thread to list
		insert(thread);

		// increment ref count to account for the thread itself
		refThread(thread);
	}

	// note that the child thread will wait until we release this mutex
	unlockMutex(m_threadMutex);

	return thread;
}

CArchThread
CArchMultithreadOS2::newCurrentThread()
{
	lockMutex(m_threadMutex);
	CArchThreadImpl* thread = find(_gettid());
	unlockMutex(m_threadMutex);
	assert(thread != NULL);
	return thread;
}

void
CArchMultithreadOS2::closeThread(CArchThread thread)
{
	assert(thread != NULL);

	// decrement ref count and clean up thread if no more references
	if (--thread->m_refCount == 0) {
		// remove thread from list
		lockMutex(m_threadMutex);
		assert(findNoRefOrCreate(thread->m_id) == thread);
		erase(thread);
		unlockMutex(m_threadMutex);

		// done with thread
		delete thread;
	}
}

CArchThread
CArchMultithreadOS2::copyThread(CArchThread thread)
{
	refThread(thread);
	return thread;
}

void
CArchMultithreadOS2::cancelThread(CArchThread thread)
{
	assert(thread != NULL);

	// set cancel flag
	DosPostEventSem(thread->m_cancel);
}

void
CArchMultithreadOS2::setPriorityOfThread(CArchThread thread, int n)
{
#if 0 /* not implemented on posix, so ignore. */
	struct CPriorityInfo {
	public:
		ULONG		m_class;
		int			m_level;
	};
	static const CPriorityInfo s_pClass[] = {
		{ IDLE_PRIORITY_CLASS,     THREAD_PRIORITY_IDLE         },
		{ IDLE_PRIORITY_CLASS,     THREAD_PRIORITY_LOWEST       },
		{ IDLE_PRIORITY_CLASS,     THREAD_PRIORITY_BELOW_NORMAL },
		{ IDLE_PRIORITY_CLASS,     THREAD_PRIORITY_NORMAL       },
		{ IDLE_PRIORITY_CLASS,     THREAD_PRIORITY_ABOVE_NORMAL },
		{ IDLE_PRIORITY_CLASS,     THREAD_PRIORITY_HIGHEST      },
		{ NORMAL_PRIORITY_CLASS,   THREAD_PRIORITY_LOWEST       },
		{ NORMAL_PRIORITY_CLASS,   THREAD_PRIORITY_BELOW_NORMAL },
		{ NORMAL_PRIORITY_CLASS,   THREAD_PRIORITY_NORMAL       },
		{ NORMAL_PRIORITY_CLASS,   THREAD_PRIORITY_ABOVE_NORMAL },
		{ NORMAL_PRIORITY_CLASS,   THREAD_PRIORITY_HIGHEST      },
		{ HIGH_PRIORITY_CLASS,     THREAD_PRIORITY_LOWEST       },
		{ HIGH_PRIORITY_CLASS,     THREAD_PRIORITY_BELOW_NORMAL },
		{ HIGH_PRIORITY_CLASS,     THREAD_PRIORITY_NORMAL       },
		{ HIGH_PRIORITY_CLASS,     THREAD_PRIORITY_ABOVE_NORMAL },
		{ HIGH_PRIORITY_CLASS,     THREAD_PRIORITY_HIGHEST      },
		{ REALTIME_PRIORITY_CLASS, THREAD_PRIORITY_IDLE         },
		{ REALTIME_PRIORITY_CLASS, THREAD_PRIORITY_LOWEST       },
		{ REALTIME_PRIORITY_CLASS, THREAD_PRIORITY_BELOW_NORMAL },
		{ REALTIME_PRIORITY_CLASS, THREAD_PRIORITY_NORMAL       },
		{ REALTIME_PRIORITY_CLASS, THREAD_PRIORITY_ABOVE_NORMAL },
		{ REALTIME_PRIORITY_CLASS, THREAD_PRIORITY_HIGHEST      },
		{ REALTIME_PRIORITY_CLASS, THREAD_PRIORITY_TIME_CRITICAL}
	};
#if defined(_DEBUG)
	// don't use really high priorities when debugging
	static const size_t s_pMax  = 13;
#else
	static const size_t s_pMax  = sizeof(s_pClass) / sizeof(s_pClass[0]) - 1;
#endif
	static const size_t s_pBase = 8;	// index of normal priority

	assert(thread != NULL);

	size_t index;
	if (n > 0 && s_pBase < (size_t)n) {
		// lowest priority
		index = 0;
	}
	else {
		index = (size_t)((int)s_pBase - n);
		if (index > s_pMax) {
			// highest priority
			index = s_pMax;
		}
	}
	SetPriorityClass(GetCurrentProcess(), s_pClass[index].m_class);
	SetThreadPriority(thread->m_thread, s_pClass[index].m_level);
#endif /* */	
}

void
CArchMultithreadOS2::testCancelThread()
{
	// find current thread
	lockMutex(m_threadMutex);
	CArchThreadImpl* thread = findNoRef(_gettid());
	unlockMutex(m_threadMutex);

	// test cancel on thread
	testCancelThreadImpl(thread);
}

bool
CArchMultithreadOS2::wait(CArchThread target, double timeout)
{
	assert(target != NULL);

	lockMutex(m_threadMutex);

	// find current thread
	CArchThreadImpl* self = findNoRef(_gettid());

	// ignore wait if trying to wait on ourself
	if (target == self) {
		unlockMutex(m_threadMutex);
		return false;
	}

	// ref the target so it can't go away while we're watching it
	refThread(target);

	unlockMutex(m_threadMutex);

	// convert timeout
	ULONG os2Timeout;
	if (timeout < 0.0) {
		os2Timeout = SEM_INDEFINITE_WAIT;
	}
	else {
		os2Timeout = (ULONG)(1000.0 * timeout);
	}

// fixme!
	// wait for this thread to be cancelled or woken up or for the
	// target thread to terminate.
	SEMRECORD handles[2];
	handles[0].hsemCur = (HSEM)target->m_exit;
	handles[0].ulUser = 0;
	handles[1].hsemCur = (HSEM)self->m_cancel;
	handles[1].ulUser = 1;
	HMUX hmux = NULLHANDLE;
	APIRET rc = DosCreateMuxWaitSem(NULL, &hmux, 2, &handles[0], DCMW_WAIT_ANY);
	if (rc != NO_ERROR) {
	    assert(rc == NO_ERROR);
	    return false;
	}
	ULONG iSem = ~0UL;
	rc = DosWaitMuxWaitSem(hmux, os2Timeout, &iSem);
	if (rc != NO_ERROR) {
		iSem = ~0UL;
	}
	DosCloseMuxWaitSem(hmux);

	// cancel takes priority
	if (	rc == NO_ERROR
		&&	iSem != 1
		&&	DosWaitEventSem((HEV)handles[1].hsemCur, 0) == NO_ERROR) {
		iSem = 1;
	}

	// release target
	closeThread(target);

	// handle result
	switch (iSem) {
	case 0:
		// target thread terminated
		return true;

	case 1:
		// this thread was cancelled.  does not return.
		testCancelThreadImpl(self);

	default:
		// timeout or error
		return false;
	}
}

bool
CArchMultithreadOS2::isSameThread(CArchThread thread1, CArchThread thread2)
{
	return (thread1 == thread2);
}

bool
CArchMultithreadOS2::isExitedThread(CArchThread thread)
{
	// poll exit event
	APIRET rc = DosWaitEventSem(thread->m_exit, 0);
	return (rc == NO_ERROR);
}

void*
CArchMultithreadOS2::getResultOfThread(CArchThread thread)
{
	lockMutex(m_threadMutex);
	void* result = thread->m_result;
	unlockMutex(m_threadMutex);
	return result;
}

IArchMultithread::ThreadID
CArchMultithreadOS2::getIDOfThread(CArchThread thread)
{
	return static_cast<ThreadID>(thread->m_id);
}

void
CArchMultithreadOS2::setSignalHandler(
				ESignal signal, SignalFunc func, void* userData)
{
	lockMutex(m_threadMutex);
	m_signalFunc[signal]     = func;
	m_signalUserData[signal] = userData;
	unlockMutex(m_threadMutex);
}

void
CArchMultithreadOS2::raiseSignal(ESignal signal)
{
	lockMutex(m_threadMutex);
	if (m_signalFunc[signal] != NULL) {
		m_signalFunc[signal](signal, m_signalUserData[signal]);
		ARCH->unblockPollSocket(m_mainThread);
	}
	else if (signal == kINTERRUPT || signal == kTERMINATE) {
		ARCH->cancelThread(m_mainThread);
	}
	unlockMutex(m_threadMutex);
}

CArchThreadImpl*
CArchMultithreadOS2::find(int id)
{
	CArchThreadImpl* impl = findNoRef(id);
	if (impl != NULL) {
		refThread(impl);
	}
	return impl;
}

CArchThreadImpl*
CArchMultithreadOS2::findNoRef(int id)
{
	CArchThreadImpl* impl = findNoRefOrCreate(id);
	if (impl == NULL) {
		// create thread for calling thread which isn't in our list and
		// add it to the list.  this won't normally happen but it can if
		// the system calls us under a new thread, like it does when we
		// run as a service.
		impl           = new CArchThreadImpl;
		impl->m_id     = _gettid();
		insert(impl);
	}
	return impl;
}

CArchThreadImpl*
CArchMultithreadOS2::findNoRefOrCreate(int id)
{
	// linear search
	for (CThreadList::const_iterator index  = m_threadList.begin();
									 index != m_threadList.end(); ++index) {
		if ((*index)->m_id == id) {
			return *index;
		}
	}
	return NULL;
}

void
CArchMultithreadOS2::insert(CArchThreadImpl* thread)
{
	assert(thread != NULL);

	// thread shouldn't already be on the list
	assert(findNoRefOrCreate(thread->m_id) == NULL);

	// append to list
	m_threadList.push_back(thread);
}

void
CArchMultithreadOS2::erase(CArchThreadImpl* thread)
{
	for (CThreadList::iterator index  = m_threadList.begin();
							   index != m_threadList.end(); ++index) {
		if (*index == thread) {
			m_threadList.erase(index);
			break;
		}
	}
}

void
CArchMultithreadOS2::refThread(CArchThreadImpl* thread)
{
	assert(thread != NULL);
	assert(findNoRefOrCreate(thread->m_id) != NULL);
	++thread->m_refCount;
}

void
CArchMultithreadOS2::testCancelThreadImpl(CArchThreadImpl* thread)
{
	assert(thread != NULL);

	// poll cancel event.  return if not set.
	APIRET rc = DosWaitEventSem(thread->m_cancel, 0);
	if (rc != NO_ERROR) {
		return;
	}

	// update cancel state
	lockMutex(m_threadMutex);
	bool cancel          = !thread->m_cancelling;
	thread->m_cancelling = true;
	ULONG ulIgnored;
	DosResetEventSem(thread->m_cancel, &ulIgnored);
	unlockMutex(m_threadMutex);

	// unwind thread's stack if cancelling
	if (cancel) {
		throw XThreadCancel();
	}
}

void
CArchMultithreadOS2::threadFunc(void* vrep)
{
	// get the thread
	CArchThreadImpl* thread = reinterpret_cast<CArchThreadImpl*>(vrep);

	// run thread
	s_instance->doThreadFunc(thread);

	// terminate the thread
	_endthread();
}

void
CArchMultithreadOS2::doThreadFunc(CArchThread thread)
{
	// wait for parent to initialize this object
	lockMutex(m_threadMutex);
	unlockMutex(m_threadMutex);

	void* result = NULL;
	try {
		// go
		result = (*thread->m_func)(thread->m_userData);
	}

	catch (XThreadCancel&) {
		// client called cancel()
	}
	catch (...) {
		// note -- don't catch (...) to avoid masking bugs
		DosPostEventSem(thread->m_exit);
		closeThread(thread);
		throw;
	}

	// thread has exited
	lockMutex(m_threadMutex);
	thread->m_result = result;
	unlockMutex(m_threadMutex);
	DosPostEventSem(thread->m_exit);

	// done with thread
	closeThread(thread);
}