/* Copyright 2010 Aaron J. Radke 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 cc.drx /**Topological sorting result of hopefully graphs (preferably DAG's but report cycles) */ class TSort[T](val sorted:Iterable[T], val cyclic:Iterable[(T,T)]){ def isDAG:Boolean = cyclic.isEmpty override def toString = { val sortList = sorted.mkString(", ") val cyclicList = cyclic.map{case (a,b) => s"$a -> $b"}.mkString(", ") s"TSort(sorted=List($sortList), cyclic=List($cyclicList))" } } object TSort{ def edges[T](edges:Iterable[(T,T)]):TSort[T] = { val deps = edges.groupBy(_._1).map{case (k,vs) => k -> vs.map{_._2}.toSet} apply(deps) } def apply[T](deps:Map[T,Iterable[T]]):TSort[T] = { val nodes = deps.keys ++ deps.values.flatten def findDeps(node:T):Iterable[T] = deps.getOrElse(node, List.empty[T]) apply(deps.keys, findDeps) } //a ghost of https://www.scala-sbt.org/0.13.12/sxr/sbt/Dag.scala.html def apply[T](nodes: Iterable[T], deps: T => Iterable[T]): TSort[T] = { import scala.collection.mutable val discovered = mutable.HashSet.empty[T] //order not important, (and still provides consistent sort results if T is a consistent hash) val finished = mutable.LinkedHashSet.empty[T] //preserve insertion order val cyclic = mutable.LinkedHashSet.empty[(T,T)] //preserve insertion order def visit(node: T, from:Option[T]): Unit = { if (!discovered(node)) { discovered(node) = true visitAll(deps(node), Some(node)) finished += node } else if (!finished(node)){ if(from.isDefined) cyclic += node -> from.get //TODO make sure all cyclic nodes are captured even if from is not defined else cyclic += node -> node //FIXME is this really needed here? // println(s"Warning: cyclic node: $node from:$from") } () } def visitAll(nodes: Iterable[T], from:Option[T]) = nodes.foreach{node => visit(node, from)} visitAll(nodes, None) new TSort(finished.toList, cyclic.toList) } }