fleshed out `evaluateTargetGraph` a little

1 files changed, 31 insertions, 4 deletions

diff --git a/src/main/scala/hbt/Main.scala b/src/main/scala/hbt/Main.scala
index b4b5757c..c6323e8f 100644
--- a/src/main/scala/hbt/Main.scala
+++ b/src/main/scala/hbt/Main.scala
@@ -3,9 +3,11 @@ import java.io.FileOutputStream
 
 import collection.JavaConverters._
 import java.nio.{file => jnio}
-
 import java.util.jar.JarEntry
+
 import sourcecode.Enclosing
+
+import scala.collection.mutable
 class Args(val args: IndexedSeq[_]){
   def length = args.length
   def apply[T](index: Int): T = {
@@ -114,8 +116,33 @@ object Main{
   }
 
   def evaluateTargetGraph[T](t: Target[T]): T = {
-    ???
-//    val evaluated = collection.mutable.Map.empty[Target[_], Any]
-//    val forwardEdges
+    val targetSet = mutable.Set.empty[Target[_]]
+    def rec(t: Target[_]): Unit = {
+      if (targetSet.contains(t)) () // do nothing
+      else {
+        targetSet.add(t)
+        t.inputs.foreach(rec)
+      }
+    }
+    rec(t)
+    val targets = targetSet.toIndexedSeq
+    val targetIndices = targets.zipWithIndex.toMap
+
+    val numberedEdges =
+      for(i <- targets.indices)
+      yield targets(i).inputs.map(targetIndices)
+
+    val sortedClusters = Tarjans(numberedEdges)
+    val nonTrivialClusters = sortedClusters.filter(_.length > 1)
+    assert(nonTrivialClusters.isEmpty, nonTrivialClusters)
+
+    val results = mutable.Map.empty[Target[_], Any]
+    for (cluster <- sortedClusters){
+      val Seq(singletonIndex) = cluster
+      val singleton = targets(singletonIndex)
+      val inputResults = singleton.inputs.map(results)
+      results(singleton) = singleton.evaluate(new Args(inputResults.toIndexedSeq))
+    }
+    results(t).asInstanceOf[T]
   }
 }
\ No newline at end of file