package hbt
import java.nio.{file => jnio}
import sourcecode.Enclosing
import scala.collection.mutable
class Args(val args: IndexedSeq[_], val dest: jnio.Path){
def length = args.length
def apply[T](index: Int): T = {
if (index >= 0 && index < args.length) args(index).asInstanceOf[T]
else throw new IndexOutOfBoundsException(s"Index $index outside of range 0 - ${args.length}")
}
}
trait Target[T]{
val label: String
val inputs: Seq[Target[_]]
def evaluate(args: Args): T
def map[V](f: T => V)(implicit path: Enclosing) = {
Target.Mapped(this, f, path.value)
}
def zip[V](other: Target[V])(implicit path: Enclosing) = {
Target.Zipped(this, other, path.value)
}
def ~[V, R](other: Target[V])
(implicit s: Implicits.Sequencer[T, V, R]): Target[R] = {
this.zip(other).map(s.apply _ tupled)
}
}
object Target{
def traverse[T](source: Seq[Target[T]])(implicit path: Enclosing) = {
Traverse[T](source, path.value)
}
case class Traverse[T](inputs: Seq[Target[T]], label: String) extends Target[Seq[T]]{
def evaluate(args: Args) = {
for (i <- 0 until args.length)
yield args(i).asInstanceOf[T]
}
}
case class Mapped[T, V](source: Target[T], f: T => V,
label: String) extends Target[V]{
def evaluate(args: Args) = f(args(0))
val inputs = List(source)
}
case class Zipped[T, V](source1: Target[T],
source2: Target[V],
label: String) extends Target[(T, V)]{
def evaluate(args: Args) = (args(0), args(0))
val inputs = List(source1, source1)
}
def path(path: jnio.Path)(implicit label: Enclosing) = Path(path, label.value)
case class Path(path: jnio.Path, label: String) extends Target[jnio.Path]{
def evaluate(args: Args) = path
val inputs = Nil
}
// case class Command(inputs: Seq[Target[jnio.Path]],
// output: Seq[Target[jnio.Path]],
// label: String) extends Target[Command.Result]
// object Command{
// case class Result(stdout: String,
// stderr: String,
// writtenFiles: Seq[jnio.Path])
// }
}
object Hbt{
def evaluateTargetGraph[T](t: Target[T])(implicit enclosing: Enclosing): T = {
val targetPaths = mutable.Map.empty[Target[_], List[String]]
def rec(t: Target[_], path: List[String]): Unit = {
if (targetPaths.contains(t)) () // do nothing
else {
val currentPath =
if (!t.label.startsWith(enclosing.value)) path.reverse
else t.label.stripPrefix(enclosing.value).drop(1).split('.').toList
targetPaths(t) = currentPath
t.inputs.zipWithIndex.foreach{case (c, i) => rec(c, i.toString :: currentPath)}
}
}
rec(t, Nil)
val targets = targetPaths.keys.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 target = targets(singletonIndex)
val inputResults = target.inputs.map(results)
val targetDestPath = jnio.Paths.get(targetPaths(target).mkString("/"))
import collection.JavaConverters._
if (jnio.Files.exists(targetDestPath)){
jnio.Files.walk(targetDestPath).iterator()
.asScala
.toArray
.reverseIterator
.map(jnio.Files.deleteIfExists)
}
results(target) = target.evaluate(
new Args(inputResults.toIndexedSeq, targetDestPath)
)
}
results(t).asInstanceOf[T]
}
}