// Streamed execution.
void Stage::execute(StreamPointTable& table)
{
typedef std::list<Stage *> StageList;
std::list<StageList> lists;
StageList stages;
table.finalize();
// Walk from the current stage backwards. As we add each input, copy
// the list of stages and push it on a list. We then pull a list from the
// front of list and keep going. Placing on the back and pulling from the
// front insures that the stages will be executed in the order that they
// were added. If we hit stage with no previous stages, we execute
// the stage list.
// All this often amounts to a bunch of list copying for
// no reason, but it's more simple than what we might otherwise do and
// this should be a nit in the grand scheme of execution time.
//
// As an example, if there are four paths from the end stage (writer) to
// reader stages, there will be four stage lists and execute(table, stages)
// will be called four times.
Stage *s = this;
stages.push_front(s);
while (true)
{
if (s->m_inputs.empty())
execute(table, stages);
else
{
for (auto s2 : s->m_inputs)
{
StageList newStages(stages);
newStages.push_front(s2);
lists.push_front(newStages);
}
}
if (lists.empty())
break;
stages = lists.back();
lists.pop_back();
s = stages.front();
}
}
// Streamed execution.
void Stage::execute(StreamPointTable& table)
{
typedef std::list<Stage *> StageList;
SpatialReference srs;
std::list<StageList> lists;
StageList stages;
StageList readies;
table.finalize();
// Walk from the current stage backwards. As we add each input, copy
// the list of stages and push it on a list. We then pull a list from the
// back of list and keep going. Pushing on the front and pulling from the
// back insures that the stages will be executed in the order that they
// were added. If we hit stage with no previous stages, we execute
// the stage list.
// All this often amounts to a bunch of list copying for
// no reason, but it's more simple than what we might otherwise do and
// this should be a nit in the grand scheme of execution time.
//
// As an example, if there are four paths from the end stage (writer) to
// reader stages, there will be four stage lists and execute(table, stages)
// will be called four times.
Stage *s = this;
stages.push_front(s);
while (true)
{
if (s->m_inputs.empty())
{
// Ready stages before we execute.
for (auto s2 : stages)
if (!Utils::contains(readies, s2))
{
s2->pushLogLeader();
s2->ready(table);
s2->pushLogLeader();
readies.push_back(s2);
srs = s2->getSpatialReference();
if (!srs.empty())
table.setSpatialReference(srs);
}
execute(table, stages);
}
else
{
for (auto s2 : s->m_inputs)
{
StageList newStages(stages);
newStages.push_front(s2);
lists.push_front(newStages);
}
}
if (lists.empty())
break;
stages = lists.back();
lists.pop_back();
s = stages.front();
}
for (auto s2 : stages)
{
s2->pushLogLeader();
s2->l_done(table);
s2->popLogLeader();
}
}
