XCEngine/engine/third_party/physx/source/foundation/unix/FdUnixSync.cpp

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#include "foundation/PxAssert.h"

#include "foundation/PxUserAllocated.h"
#include "foundation/PxSync.h"

#include <errno.h>
#include <stdio.h>
#include <pthread.h>
#include <time.h>
#include <sys/time.h>

namespace physx
{

namespace
{
class SyncImpl
{
  public:
	pthread_mutex_t mutex;
	pthread_cond_t cond;
	volatile int setCounter;
	volatile bool is_set;
};

SyncImpl* getSync(PxSyncImpl* impl)
{
	return reinterpret_cast<SyncImpl*>(impl);
}
}

uint32_t PxSyncImpl::getSize()
{
	return sizeof(SyncImpl);
}

struct PxUnixScopeLock
{
	PxUnixScopeLock(pthread_mutex_t& m) : mMutex(m)
	{
		pthread_mutex_lock(&mMutex);
	}

	~PxUnixScopeLock()
	{
		pthread_mutex_unlock(&mMutex);
	}

  private:
	pthread_mutex_t& mMutex;
};

PxSyncImpl::PxSyncImpl()
{
	int status = pthread_mutex_init(&getSync(this)->mutex, 0);
	PX_ASSERT(!status);
	status = pthread_cond_init(&getSync(this)->cond, 0);
	PX_ASSERT(!status);
	PX_UNUSED(status);
	getSync(this)->is_set = false;
	getSync(this)->setCounter = 0;
}

PxSyncImpl::~PxSyncImpl()
{
	pthread_cond_destroy(&getSync(this)->cond);
	pthread_mutex_destroy(&getSync(this)->mutex);
}

void PxSyncImpl::reset()
{
	PxUnixScopeLock lock(getSync(this)->mutex);
	getSync(this)->is_set = false;
}

void PxSyncImpl::set()
{
	PxUnixScopeLock lock(getSync(this)->mutex);
	if(!getSync(this)->is_set)
	{
		getSync(this)->is_set = true;
		getSync(this)->setCounter++;
		pthread_cond_broadcast(&getSync(this)->cond);
	}
}

bool PxSyncImpl::wait(uint32_t ms)
{
	PxUnixScopeLock lock(getSync(this)->mutex);
	int lastSetCounter = getSync(this)->setCounter;
	if(!getSync(this)->is_set)
	{
		if(ms == uint32_t(-1))
		{
			// have to loop here and check is_set since pthread_cond_wait can return successfully
			// even if it was not signaled by pthread_cond_broadcast (OS efficiency design decision)
			int status = 0;
			while(!status && !getSync(this)->is_set && (lastSetCounter == getSync(this)->setCounter))
				status = pthread_cond_wait(&getSync(this)->cond, &getSync(this)->mutex);
			PX_ASSERT((!status && getSync(this)->is_set) || (lastSetCounter != getSync(this)->setCounter));
		}
		else
		{
			timespec ts;
			timeval tp;
			gettimeofday(&tp, NULL);
			uint32_t sec = ms / 1000;
			uint32_t usec = (ms - 1000 * sec) * 1000;

			// sschirm: taking into account that us might accumulate to a second
			// otherwise the pthread_cond_timedwait complains on osx.
			usec = tp.tv_usec + usec;
			uint32_t div_sec = usec / 1000000;
			uint32_t rem_usec = usec - div_sec * 1000000;

			ts.tv_sec = tp.tv_sec + sec + div_sec;
			ts.tv_nsec = rem_usec * 1000;

			// have to loop here and check is_set since pthread_cond_timedwait can return successfully
			// even if it was not signaled by pthread_cond_broadcast (OS efficiency design decision)
			int status = 0;
			while(!status && !getSync(this)->is_set && (lastSetCounter == getSync(this)->setCounter))
				status = pthread_cond_timedwait(&getSync(this)->cond, &getSync(this)->mutex, &ts);
			PX_ASSERT((!status && getSync(this)->is_set) || (status == ETIMEDOUT) ||
			          (lastSetCounter != getSync(this)->setCounter));
		}
	}
	return getSync(this)->is_set || (lastSetCounter != getSync(this)->setCounter);
}

} // namespace physx