// Some of the graph algorithms assume that the nodes array is sorted
// topologically (inputs are always before outputs), but some operations
// (like graph rewriting) can change that. This function restores that order.
- void sort_nodes_topologically();
- void topological_sort_visit_node(Node *node, std::set<Node *> *visited_nodes, std::vector<Node *> *sorted_list);
+ void sort_all_nodes_topologically();
+
+ // Do the actual topological sort. <nodes> must be a connected, acyclic subgraph;
+ // links that go to nodes not in the set will be ignored.
+ std::vector<Node *> topological_sort(const std::vector<Node *> &nodes);
+
+ // Utility function used by topological_sort() to do a depth-first search.
+ // The reason why we store nodes left to visit instead of a more conventional
+ // list of nodes to visit is that we want to be able to limit ourselves to
+ // a subgraph instead of all nodes. The set thus serves a dual purpose.
+ void topological_sort_visit_node(Node *node, std::set<Node *> *nodes_left_to_visit, std::vector<Node *> *sorted_list);
// Used during finalize().
void find_color_spaces_for_inputs();