func tarjanSort(successors map[bson.ObjectId][]bson.ObjectId) [][]bson.ObjectId {
// http://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm
data := &tarjanData{
successors: successors,
nodes: make([]tarjanNode, 0, len(successors)),
index: make(map[bson.ObjectId]int, len(successors)),
}
// Sort all nodes to stabilize the logic.
var all []string
for id := range successors {
all = append(all, string(id))
}
sort.Strings(all)
for _, strid := range all {
id := bson.ObjectId(strid)
if _, seen := data.index[id]; !seen {
data.strongConnect(id)
}
}
return data.output
}
func bid(n int) bson.ObjectId {
return bson.ObjectId(fmt.Sprintf("%024d", n))
}
// MarshalJSON turns a dal.ObjectId into a json.Marshaller.
func (id ObjectID) MarshalJSON() ([]byte, error) {
return bson.ObjectId(id).MarshalJSON()
}
func (id ObjectID) Valid() bool {
return bson.ObjectId(id).Valid()
}
func (id ObjectID) Hex() string {
return bson.ObjectId(id).Hex()
}
func (id ObjectID) GetBSON() (interface{}, error) {
return bson.ObjectId(id), nil
}