private static ISet<int> GetInnerStreams(
int fromStream,
ISet<int> toStreams,
OuterInnerDirectionalGraph outerInnerGraph,
InnerJoinGraph innerJoinGraph,
ISet<int> completedStreams)
{
ISet<int> innerStreams = new HashSet<int>();
foreach (var toStream in toStreams) {
if (outerInnerGraph.IsInner(fromStream, toStream)) {
// if the to-stream, recursively, has an inner join itself, it becomes a required stream and not optional
var hasInnerJoin = false;
if (!innerJoinGraph.IsEmpty()) {
var doNotUseStreams = new HashSet<int>(completedStreams);
completedStreams.Add(fromStream);
hasInnerJoin = RecursiveHasInnerJoin(
toStream,
outerInnerGraph,
innerJoinGraph,
doNotUseStreams);
}
if (!hasInnerJoin) {
innerStreams.Add(toStream);
}
}
}
return innerStreams;
}
