Serialization using play-json now mostly in place

"pure" targets which depend only on their inputs are modeled but their evaluation semantics aren't fleshed out

6 files changed, 129 insertions, 46 deletions

diff --git a/build.sbt b/build.sbt
index 30b81658..72289a15 100644
--- a/build.sbt
+++ b/build.sbt
@@ -15,7 +15,8 @@ libraryDependencies ++= Seq(
   "org.scala-lang" % "scala-compiler" % scalaVersion.value % "provided",
   "com.lihaoyi" %% "sourcecode" % "0.1.4",
   "com.lihaoyi" %% "pprint" % "0.5.3",
-  "com.lihaoyi" %% "ammonite-ops" % "1.0.2"
+  "com.lihaoyi" %% "ammonite-ops" % "1.0.2",
+  "com.typesafe.play" %% "play-json" % "2.6.6"
 )
 
 sourceGenerators in Compile += Def.task {
diff --git a/src/main/scala/forge/DefCtx.scala b/src/main/scala/forge/DefCtx.scala
index 97f9bf3f..3439f755 100644
--- a/src/main/scala/forge/DefCtx.scala
+++ b/src/main/scala/forge/DefCtx.scala
@@ -6,7 +6,9 @@ import scala.language.experimental.macros
 import scala.reflect.macros.blackbox._
 
 
-final case class DefCtx(label: String)
+final case class DefCtx(baseLabel: String, anonId: Option[Int]){
+  def label = baseLabel + anonId.getOrElse("")
+}
 object DefCtx{
   @compileTimeOnly("A DefCtx can only be provided directly within a T{} macro")
   implicit def dummy: DefCtx with Int = ???
@@ -22,7 +24,7 @@ object T{
       override def transform(tree: c.Tree): c.Tree = {
         if (tree.toString.startsWith("forge.") && tree.toString.endsWith(".DefCtx.dummy")) {
           count += 1
-          c.typecheck(q"forge.DefCtx(sourcecode.Enclosing() + $count)")
+          c.typecheck(q"forge.DefCtx(sourcecode.Enclosing(), Some($count))")
         }else tree match{
           case Apply(fun, args) =>
             val extendedParams = fun.tpe.paramLists.head.padTo(
@@ -61,7 +63,7 @@ object T{
         val newArgs = for(x <- args) yield {
           if (x.toString.startsWith("forge.") && x.toString.endsWith(".DefCtx.dummy")) {
             isTransformed = true
-            c.typecheck(q"forge.DefCtx(sourcecode.Enclosing())")
+            c.typecheck(q"forge.DefCtx(sourcecode.Enclosing(), None)")
           }else transformer.transform(x)
         }
 
diff --git a/src/main/scala/forge/Evaluator.scala b/src/main/scala/forge/Evaluator.scala
index 43b4f353..1bff722b 100644
--- a/src/main/scala/forge/Evaluator.scala
+++ b/src/main/scala/forge/Evaluator.scala
@@ -2,6 +2,7 @@ package forge
 
 import java.nio.{file => jnio}
 
+import play.api.libs.json.Json
 import sourcecode.Enclosing
 
 import scala.collection.mutable
@@ -9,8 +10,7 @@ import scala.collection.mutable
 class Evaluator(workspacePath: jnio.Path,
                 enclosingBase: DefCtx){
 
-  val resultCache = mutable.Map.empty[String, (Int, Any)]
-
+  val resultCache = mutable.Map.empty[String, (Int, String)]
   def evaluate(targets: Seq[Target[_]]): Evaluator.Results = {
     jnio.Files.createDirectories(workspacePath)
 
@@ -20,26 +20,29 @@ class Evaluator(workspacePath: jnio.Path,
     for (target <- sortedTargets){
       val inputResults = target.inputs.map(results).toIndexedSeq
 
-      val targetDestPath = {
-        val enclosingStr = target.defCtx.label
-        val targetDestPath = workspacePath.resolve(
-          jnio.Paths.get(enclosingStr.stripSuffix(enclosingBase.label))
-        )
-        deleteRec(targetDestPath)
-        targetDestPath
-
-      }
+      val enclosingStr = target.defCtx.label
+      val targetDestPath = workspacePath.resolve(
+        jnio.Paths.get(enclosingStr.stripSuffix(enclosingBase.label))
+      )
+      deleteRec(targetDestPath)
 
       val inputsHash = inputResults.hashCode
-      resultCache.get(target.defCtx.label) match{
-        case Some((hash, res)) if hash == inputsHash && !target.dirty =>
-          results(target) = res
+      (target.dirty, resultCache.get(target.defCtx.label)) match{
+        case (Some(dirtyCheck), Some((hash, res)))
+          if hash == inputsHash && !dirtyCheck() =>
+          results(target) = target.formatter.reads(Json.parse(res)).get
+
         case _ =>
           evaluated.append(target)
-          val res = target.evaluate(new Args(inputResults, targetDestPath))
+          if (target.defCtx.anonId.isDefined && target.dirty.isEmpty) {
+            val res = target.evaluate(new Args(inputResults, targetDestPath))
+            results(target) = res
+          }else{
+            val (res, serialized) = target.evaluateAndWrite(new Args(inputResults, targetDestPath))
+            resultCache(target.defCtx.label) = (inputsHash, serialized)
+            results(target) = res
+          }
 
-          resultCache(target.defCtx.label) = (inputsHash, res)
-          results(target) = res
       }
 
     }
diff --git a/src/main/scala/forge/Target.scala b/src/main/scala/forge/Target.scala
index d8536c60..93fa022e 100644
--- a/src/main/scala/forge/Target.scala
+++ b/src/main/scala/forge/Target.scala
@@ -2,7 +2,8 @@ package forge
 
 import java.nio.{file => jnio}
 
-trait Target[T] extends Target.Ops[T]{
+import play.api.libs.json.{Format, Json}
+abstract class Target[T](implicit formatter: Format[T]) extends Target.Ops[T]{
   /**
     * Where in the Scala codebase was this target defined?
     */
@@ -19,62 +20,78 @@ trait Target[T] extends Target.Ops[T]{
 
   /**
     * Even if this target's inputs did not change, does it need to re-evaluate
-    * anyway? e.g. if the files this target represents on disk changed
+    * anyway?
+    *
+    * - None means it never needs to re-evaluate unless its inputs do
+    * - Some(f) contains a function that returns whether or not it should re-evaluate,
+    *   e.g. if the files this target represents on disk changed
     */
-  def dirty: Boolean = false
+  val dirty: Option[() => Boolean] = Some(() => false)
 
 }
 
 object Target{
-  trait Ops[T]{ this: Target[T] =>
+  abstract class Ops[T](implicit val formatter: Format[T]){ this: Target[T] =>
+    def evaluateAndWrite(args: Args): (T, String) = {
+      val res = evaluate(args)
+      val str = formatter.writes(res)
+      (res, Json.stringify(str))
+    }
     val defCtx: DefCtx
-    def map[V](f: T => V)(implicit defCtx: DefCtx) = {
+    def map[V: Format](f: T => V)(implicit defCtx: DefCtx) = {
       new Target.Mapped(this, f, defCtx)
     }
-    def zip[V](other: Target[V])(implicit defCtx: DefCtx) = {
+    def zip[V: Format](other: Target[V])(implicit defCtx: DefCtx) = {
       new Target.Zipped(this, other, defCtx)
     }
-    def ~[V, R](other: Target[V])
+    def ~[V: Format, R: Format](other: Target[V])
                (implicit s: Implicits.Sequencer[T, V, R], defCtx: DefCtx): Target[R] = {
       this.zip(other).map(s.apply _ tupled)
     }
 
     override def toString = this.getClass.getName + "@" + defCtx.label
   }
-  def test(inputs: Target[Int]*)(implicit defCtx: DefCtx) = new Test(inputs, defCtx)
+  def test(inputs: Target[Int]*)(implicit defCtx: DefCtx) = {
+    new Test(inputs, defCtx, pure = false)
+  }
+  def testPure(inputs: Target[Int]*)(implicit defCtx: DefCtx) = {
+    new Test(inputs, defCtx, pure = true)
+  }
 
   /**
     * A dummy target that takes any number of inputs, and whose output can be
     * controlled externally, so you can construct arbitrary dataflow graphs and
     * test how changes propagate.
     */
-  class Test(val inputs: Seq[Target[Int]], val defCtx: DefCtx) extends Target[Int]{
+  class Test(val inputs: Seq[Target[Int]],
+             val defCtx: DefCtx,
+             val pure: Boolean) extends Target[Int]{
     var counter = 0
     var lastCounter = counter
     def evaluate(args: Args) = {
       lastCounter = counter
-      counter + args.args.map(_.asInstanceOf[Int]).sum
+        counter + args.args.map(_.asInstanceOf[Int]).sum
     }
-    override def dirty = lastCounter != counter
+    override val dirty = if (pure) None else Some(() => lastCounter != counter)
   }
-  def traverse[T](source: Seq[Target[T]])(implicit defCtx: DefCtx) = {
+  def traverse[T: Format](source: Seq[Target[T]])(implicit defCtx: DefCtx) = {
     new Traverse[T](source, defCtx)
   }
-  class Traverse[T](val inputs: Seq[Target[T]], val defCtx: DefCtx) extends Target[Seq[T]]{
+  class Traverse[T: Format](val inputs: Seq[Target[T]], val defCtx: DefCtx) extends Target[Seq[T]]{
     def evaluate(args: Args) = {
       for (i <- 0 until args.length)
       yield args(i).asInstanceOf[T]
     }
 
   }
-  class Mapped[T, V](source: Target[T], f: T => V,
-                     val defCtx: DefCtx) extends Target[V]{
+  class Mapped[T, V: Format](source: Target[T], f: T => V,
+                              val defCtx: DefCtx) extends Target[V]{
     def evaluate(args: Args) = f(args(0))
     val inputs = List(source)
   }
-  class Zipped[T, V](source1: Target[T],
-                     source2: Target[V],
-                     val defCtx: DefCtx) extends Target[(T, V)]{
+  class Zipped[T: Format, V: Format](source1: Target[T],
+                                     source2: Target[V],
+                                     val defCtx: DefCtx) extends Target[(T, V)]{
     def evaluate(args: Args) = (args(0), args(0))
     val inputs = List(source1, source1)
   }
diff --git a/src/main/scala/forge/package.scala b/src/main/scala/forge/package.scala
new file mode 100644
index 00000000..8145acd3
--- /dev/null
+++ b/src/main/scala/forge/package.scala
@@ -0,0 +1,46 @@
+import play.api.libs.json._
+import java.nio.{file => jnio}
+
+import ammonite.ops.Bytes
+
+package object forge {
+
+  implicit object pathFormat extends Format[jnio.Path]{
+    def reads(json: JsValue) = json match{
+      case JsString(v) => JsSuccess(jnio.Paths.get(v))
+      case _ => JsError("Paths must be a String")
+    }
+    def writes(o: jnio.Path) = JsString(o.toAbsolutePath.toString)
+  }
+
+  implicit object bytesFormat extends Format[Bytes]{
+    def reads(json: JsValue) = json match{
+      case JsString(v) => JsSuccess(
+        new Bytes(javax.xml.bind.DatatypeConverter.parseBase64Binary(v))
+      )
+      case _ => JsError("Bytes must be a String")
+    }
+    def writes(o: Bytes) = {
+      JsString(javax.xml.bind.DatatypeConverter.printBase64Binary(o.array))
+    }
+  }
+
+  implicit def EitherFormat[T: Format, V: Format] = new Format[Either[T, V]]{
+    def reads(json: JsValue) = json match{
+      case JsObject(struct) =>
+        (struct.get("type"), struct.get("value")) match{
+          case (Some(JsString("Left")), Some(v)) => implicitly[Reads[T]].reads(v).map(Left(_))
+          case (Some(JsString("Right")), Some(v)) => implicitly[Reads[V]].reads(v).map(Right(_))
+          case _ => JsError("Either object layout is unknown")
+        }
+      case _ => JsError("Either must be an Object")
+    }
+    def writes(o: Either[T, V]) = o match{
+      case Left(v) => Json.obj("type" -> "Left", "value" -> implicitly[Writes[T]].writes(v))
+      case Right(v) => Json.obj("type" -> "Right", "value" -> implicitly[Writes[V]].writes(v))
+    }
+  }
+
+  implicit val crFormat = Json.format[ammonite.ops.CommandResult]
+  implicit val tsFormat = Json.format[Target.Subprocess.Result]
+}
diff --git a/src/test/scala/forge/ForgeTests.scala b/src/test/scala/forge/ForgeTests.scala
index 51df4c5f..6c588d4f 100644
--- a/src/test/scala/forge/ForgeTests.scala
+++ b/src/test/scala/forge/ForgeTests.scala
@@ -1,13 +1,13 @@
 package forge
 
 import utest._
-import Target.test
+import Target.{test, testPure}
 import java.nio.{file => jnio}
 object ForgeTests extends TestSuite{
 
   val tests = Tests{
-    val baseCtx = DefCtx("forge.ForgeTests.tests ")
-    val evaluator = new Evaluator(jnio.Paths.get("target/workspace"), baseCtx)
+    val baseCtx = DefCtx("forge.ForgeTests.tests ", None)
+
     object Singleton {
       val single = T{ test() }
     }
@@ -31,6 +31,11 @@ object ForgeTests extends TestSuite{
       val down = T{ test(test(up), test(up)) }
     }
 
+    object AnonImpureDiamond{
+      val up = T{ test() }
+      val down = T{ test(testPure(up), test(up)) }
+    }
+
 
     'syntaxLimits - {
       // Make sure that we properly prohibit cases where a `test()` target can
@@ -161,9 +166,9 @@ object ForgeTests extends TestSuite{
 
     }
     'evaluateSingle - {
-      def check(target: Target[_],
-                expValue: Any,
-                expEvaled: Seq[Target[_]]) = {
+      val evaluator = new Evaluator(jnio.Paths.get("target/workspace"), baseCtx)
+
+      def check(target: Target[_], expValue: Any, expEvaled: Seq[Target[_]]) = {
         val Evaluator.Results(returnedValues, returnedEvaluated) = evaluator.evaluate(Seq(target))
         assert(
           returnedValues == Seq(expValue),
@@ -228,7 +233,7 @@ object ForgeTests extends TestSuite{
         right.counter += 1
         check(down, expValue = 5, expEvaled = Seq(right, down))
       }
-      'anoniamond - {
+      'anonDiamond - {
         import AnonDiamond._
         val left = down.inputs(0).asInstanceOf[Target.Test]
         val right = down.inputs(1).asInstanceOf[Target.Test]
@@ -247,6 +252,15 @@ object ForgeTests extends TestSuite{
         right.counter += 1
         check(down, expValue = 5, expEvaled = Seq(right, down))
       }
+//      'anonImpureDiamond - {
+//        import AnonImpureDiamond._
+//        val left = down.inputs(0).asInstanceOf[Target.Test]
+//        val right = down.inputs(1).asInstanceOf[Target.Test]
+//        check(down, expValue = 0, expEvaled = Seq(up, left, right, down))
+//
+//        down.counter += 1
+//        check(down, expValue = 1, expEvaled = Seq(left, down))
+//      }
     }