init

vendor/github.com/awalterschulze/gographviz/relations.go

@@ -0,0 +1,64 @@
+//Copyright 2013 GoGraphviz 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 gographviz
+
+import (
+	"sort"
+)
+
+// Relations represents the relations between graphs and nodes.
+// Each node belongs the main graph or a subgraph.
+type Relations struct {
+	ParentToChildren map[string]map[string]bool
+	ChildToParents   map[string]map[string]bool
+}
+
+// NewRelations creates an empty set of relations.
+func NewRelations() *Relations {
+	return &Relations{make(map[string]map[string]bool), make(map[string]map[string]bool)}
+}
+
+// Add adds a node to a parent graph.
+func (relations *Relations) Add(parent string, child string) {
+	if _, ok := relations.ParentToChildren[parent]; !ok {
+		relations.ParentToChildren[parent] = make(map[string]bool)
+	}
+	relations.ParentToChildren[parent][child] = true
+	if _, ok := relations.ChildToParents[child]; !ok {
+		relations.ChildToParents[child] = make(map[string]bool)
+	}
+	relations.ChildToParents[child][parent] = true
+}
+
+// Remove removes relation
+func (relations *Relations) Remove(parent string, child string) {
+	if _, ok := relations.ParentToChildren[parent]; ok {
+		delete(relations.ParentToChildren[parent], child)
+	}
+
+	if _, ok := relations.ChildToParents[child]; ok {
+		delete(relations.ChildToParents[child], parent)
+	}
+}
+
+// SortedChildren returns a list of sorted children of the given parent graph.
+func (relations *Relations) SortedChildren(parent string) []string {
+	keys := make([]string, 0)
+	for key := range relations.ParentToChildren[parent] {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	return keys
+}