[vtkusers] Track all downstream filters MTime

[Dmitry Gurulev]

Hi All!

I'm writing custom filter and part of it executed at working thread.
Since, I require track all downstream filters to be up-to-date before
modify internal data to avoid:
1. frequent filter execution (can be heavy).
2. data sets inconsistency (filter produce 3 data set)

Eg. -
filter + 2 mappers.
1. 1st mapper request execution -> filter up-to-date
2. 2nd mapper request execution -> filter execution again, since working 
thread call Modified()!

Now I've solved this problem such way-
-------------part of filter executed at working thread-------------
bool my_filter::cache(void const* buffer, size_t size)
{
	boost::try_mutex::scoped_try_lock l(guard_);
	if (!l.locked())
		return false;

	unsigned long time = unsigned long(-1);
	unsigned long const m_time = GetMTime();

	vtkInformationVector* ov = 								GetExecutive()->GetOutputInformation();
	int const n_obj = ov->GetNumberOfInformationObjects();
	for (int i = 0; i < n_obj ; ++i)
	{
		vtkInformation* info = ov->GetInformationObject(i);
		int const length = 									info->Length(vtkExecutive::CONSUMERS());
		if (!length)
			break;

		vtkExecutive** consumers = 							 
info->GetExecutives(vtkExecutive::CONSUMERS());
		for (int j = 0; j < length; ++j)
		{
			vtkDemandDrivenPipeline* pipe = 				 
vtkDemandDrivenPipeline::SafeDownCast(consumers[j]);
		unsigned long const ctime = pipe ? 							pipe->GetPipelineMTime() : 0;
			
			if (ctime < time)
				time = ctime;
			AtlTrace(_T("\n%X - %d"), pipe, ctime);
		}
	}

	AtlTrace(_T("\nMin - %d, Modified - %d"), time, m_time);

	if (m_time != 0 && time < m_time)
	{
		//some consuners have pipeline time less then MTime - 				//i.e. not 
updated yet
		//skip internal data modification
		AtlTrace(_T(" --- Skipped"));
		return false;
	}

	//modify internal data
	Modified(); //say we are modify data
-------------

Is there more direct way to solve my problem?
Is there way to solve it on old pipeline (v 4.4)?

PS Use pretty old CVS revision of VTK 5 version (since ~ 2007 
September), WinXP SP 2, VS 2003 (7.1)