func (h *Renderer) Provision(g canvas.Graph, nodes []InterfaceNode) (err error) {
newIds := []canvas.NodeIfc{}
visitFn := func(prev, this canvas.Node) {
provisionNode(g, this, &newIds)
}
t := canvas.NewDepthFirst(visitFn, filterInterfaceNode)
defer func() {
if r := recover(); r != nil {
switch r := r.(type) {
case error:
err = r
for _, ni := range newIds {
g.Node(ni.ID()).ReleaseInterfaceID(ni.Ifc())
}
// rollback
default:
panic(r)
}
}
}()
// Find all of the Adapter (internal) nodes reachable from an external interface.
// Collect the ID of each node and update the modules table.
for _, node := range nodes {
if node.ID() < 0 {
continue
}
provisionNode(g, node, &newIds)
t.Walk(g, node, nil)
}
return
}
