// Merge merges the nodes of the isomorphism of sub in graph into a single node.
// If successful it returns the name of the new node.
func Merge(graph *dot.Graph, m map[string]string, sub *graphs.SubGraph) (name string, err error) {
var nodes []*dot.Node
for _, gname := range m {
node, ok := graph.Nodes.Lookup[gname]
if !ok {
return "", errutil.Newf("unable to locate mapping for node %q", gname)
}
nodes = append(nodes, node)
}
name = uniqName(graph, sub.Name)
entry, ok := graph.Nodes.Lookup[m[sub.Entry()]]
if !ok {
return "", errutil.Newf("unable to locate mapping for entry node %q", sub.Entry())
}
exit, ok := graph.Nodes.Lookup[m[sub.Exit()]]
if !ok {
return "", errutil.Newf("unable to locate mapping for exit node %q", sub.Exit())
}
err = graph.Replace(nodes, name, entry, exit)
if err != nil {
return "", errutil.Err(err)
}
return name, nil
}
