func count(n Node, compute func() ([]lattice.Node, error), counts bytes_int.MultiMap) (int, error) {
if has, err := counts.Has(n.Label()); err != nil {
return 0, err
} else if !has {
nodes, err := compute()
if err != nil {
return 0, err
}
return len(nodes), nil
}
var count int32
err := counts.DoFind(n.Label(), func(_ []byte, c int32) error {
count = c
return nil
})
if err != nil {
return 0, err
}
return int(count), nil
}
