private static void MakeLeanMSG2(Store msg, ResSet predicates, StatementSink removed,
ResSet nodesremoved, BNode startingnode)
{
// Find every pair of two distinct outgoing edges from startingnode
// with the same predicate, targeting entities only.
MultiMap edges = new MultiMap();
foreach (Statement s in msg.Select(new Statement(startingnode, null, null)))
{
if (s.Object is Entity)
{
edges.Put(new Edge(true, startingnode, s.Predicate, null), s.Object);
}
}
foreach (Statement s in msg.Select(new Statement(null, null, startingnode)))
{
edges.Put(new Edge(false, startingnode, s.Predicate, null), s.Subject);
}
foreach (Edge e in edges.Keys)
{
// Make sure we have a distinct set of targets.
ResSet targets_set = new ResSet();
foreach (Entity r in edges.Get(e))
{
targets_set.Add(r);
}
if (targets_set.Count == 1)
{
continue;
}
IList targets = targets_set.ToEntityArray();
// Take every pair of targets, provided
// one is a bnode that can be a variable.
for (int i = 0; i < targets.Count; i++)
{
if (!(targets[i] is BNode) || predicates.Contains((BNode)targets[i]))
{
continue;
}
if (nodesremoved.Contains((BNode)targets[i]))
{
continue;
}
for (int j = 0; j < targets.Count; j++)
{
if (i == j)
{
continue;
}
// Create a new synchronous-path object.
SyncPath p = new SyncPath();
p.FixedNodes.Add((Resource)targets[j]);
p.FrontierVariables.Add((Resource)targets[i]);
p.Mapping[targets[i]] = targets[j];
p.Path[new Edge(e.Direction, e.Start, e.Predicate, (BNode)targets[i])] = p.Path;
if (MakeLeanMSG3(msg, predicates, removed, nodesremoved, p))
{
break; // the target was removed
}
}
}
}
}