Add an API to traverse the process graph downstream

2 files changed, 30 insertions, 0 deletions

diff --git a/libs/ardour/ardour/route_graph.h b/libs/ardour/ardour/route_graph.h
index e1e1049cd6..aae2ba019d 100644
--- a/libs/ardour/ardour/route_graph.h
+++ b/libs/ardour/ardour/route_graph.h
@@ -44,6 +44,7 @@ public:
 
 	void add (GraphVertex from, GraphVertex to, bool via_sends_only);
 	bool has (GraphVertex from, GraphVertex to, bool* via_sends_only);
+	bool feeds (GraphVertex from, GraphVertex to);
 	std::set<GraphVertex> from (GraphVertex r) const;
 	void remove (GraphVertex from, GraphVertex to);
 	bool has_none_to (GraphVertex to) const;
@@ -56,6 +57,7 @@ private:
 	typedef std::multimap<GraphVertex, std::pair<GraphVertex, bool> > EdgeMapWithSends;
 
 	EdgeMapWithSends::iterator find_in_from_to_with_sends (GraphVertex, GraphVertex);
+	EdgeMapWithSends::iterator find_recursively_in_from_to_with_sends (GraphVertex, GraphVertex);
 
 	/** map of edges with from as `first' and to as `second' */
 	EdgeMap _from_to;
diff --git a/libs/ardour/route_graph.cc b/libs/ardour/route_graph.cc
index ab88a0d839..910141a440 100644
--- a/libs/ardour/route_graph.cc
+++ b/libs/ardour/route_graph.cc
@@ -59,6 +59,24 @@ GraphEdges::find_in_from_to_with_sends (GraphVertex from, GraphVertex to)
 	return _from_to_with_sends.end ();
 }
 
+GraphEdges::EdgeMapWithSends::iterator
+GraphEdges::find_recursively_in_from_to_with_sends (GraphVertex from, GraphVertex to)
+{
+	typedef EdgeMapWithSends::iterator Iter;
+	pair<Iter, Iter> r = _from_to_with_sends.equal_range (from);
+	for (Iter i = r.first; i != r.second; ++i) {
+		if (i->second.first == to) {
+			return i;
+		}
+		GraphEdges::EdgeMapWithSends::iterator t = find_recursively_in_from_to_with_sends (i->second.first, to);
+		if (t != _from_to_with_sends.end ()) {
+			return t;
+		}
+	}
+
+	return _from_to_with_sends.end ();
+}
+
 /** @param via_sends_only if non-0, filled in with true if the edge is a
  *  path via a send only.
  *  @return true if the given edge is present.
@@ -78,6 +96,16 @@ GraphEdges::has (GraphVertex from, GraphVertex to, bool* via_sends_only)
 	return true;
 }
 
+bool
+GraphEdges::feeds (GraphVertex from, GraphVertex to)
+{
+	EdgeMapWithSends::iterator i = find_recursively_in_from_to_with_sends (from, to);
+	if (i == _from_to_with_sends.end ()) {
+		return false;
+	}
+	return true;
+}
+
 /** @return the vertices that are fed from `r' */
 set<GraphVertex>
 GraphEdges::from (GraphVertex r) const