k3s/vendor/k8s.io/gengo/generator/transitive_closure.go
2019-12-15 23:28:25 -07:00

66 lines
1.3 KiB
Go

/*
Copyright 2019 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package generator
import "sort"
type edge struct {
from string
to string
}
func transitiveClosure(in map[string][]string) map[string][]string {
adj := make(map[edge]bool)
imports := make(map[string]struct{})
for from, tos := range in {
for _, to := range tos {
adj[edge{from, to}] = true
imports[to] = struct{}{}
}
}
// Warshal's algorithm
for k := range in {
for i := range in {
if !adj[edge{i, k}] {
continue
}
for j := range imports {
if adj[edge{i, j}] {
continue
}
if adj[edge{k, j}] {
adj[edge{i, j}] = true
}
}
}
}
out := make(map[string][]string, len(in))
for i := range in {
for j := range imports {
if adj[edge{i, j}] {
out[i] = append(out[i], j)
}
}
sort.Strings(out[i])
}
return out
}