From 8a4fca72f786ffd0d389bc5f0af59063b9b03ff4 Mon Sep 17 00:00:00 2001
From: Roland <rk@rkuhn.info>
Date: Mon, 31 Dec 2012 18:38:06 +0100
Subject: [PATCH] add selfChannel and createChildren

---
 .../scala/akka/channels/ChannelSpec.scala     | 54 +++++++++++++++++--
 .../main/scala/akka/channels/Channels.scala   | 45 +++++++++++++++-
 2 files changed, 94 insertions(+), 5 deletions(-)

diff --git a/akka-macro-tests/src/test/scala/akka/channels/ChannelSpec.scala b/akka-macro-tests/src/test/scala/akka/channels/ChannelSpec.scala
index 056ee6ec34..7263ebc3c9 100644
--- a/akka-macro-tests/src/test/scala/akka/channels/ChannelSpec.scala
+++ b/akka-macro-tests/src/test/scala/akka/channels/ChannelSpec.scala
@@ -13,7 +13,7 @@ import scala.tools.reflect.ToolBoxError
 object ChannelSpec {
 
   trait Msg
-  
+
   trait A extends Msg
   object A extends A
   object A1 extends A
@@ -21,10 +21,10 @@ object ChannelSpec {
 
   trait B extends Msg
   object B extends B
-  
+
   trait C extends Msg
   object C extends C
-  
+
   trait D extends Msg
   object D extends D
 
@@ -49,6 +49,24 @@ object ChannelSpec {
         x ! C
     }
   }
+
+  // pos compile test for children
+  class Children extends Channels[Parent[TNil], Channel[A, B] :=: Channel[C, D] :=: TNil] {
+    val c = createChild(new Channels[Parent[A :-: TNil], Channel[B, C]:=: TNil] {
+      channel[B] { case (B, s) ⇒ s ! C }
+    })
+
+    var client: ActorRef = _
+    channel[A] {
+      case (A, s) ⇒ c ! B; client = sender
+    }
+    channel[C] {
+      case (C, _) ⇒ client ! C
+    }
+
+    createChild(new Channels[Parent[C :-: TNil], TNil])
+    createChild(new Channels[Parent[A :-: C :-: TNil], TNil])
+  }
 }
 
 class ChannelSpec extends AkkaSpec with ImplicitSender {
@@ -151,6 +169,36 @@ class ChannelSpec extends AkkaSpec with ImplicitSender {
       }.message must include("This ChannelRef does not support messages of type akka.channels.ChannelSpec.C.type")
     }
 
+    "not permit Nothing children" in {
+      intercept[ToolBoxError] {
+        eval("""
+            |import akka.channels._
+            |import ChannelSpec._
+            |new Channels[Parent[TNil], Channel[A, B] :=: Channel[C, D] :=: TNil] {
+            |  createChild(new Channels)
+            |}
+            """.stripMargin)
+      }.message must include("Parent argument must not be Nothing")
+    }
+
+    "not permit too demanding children" in {
+      intercept[ToolBoxError] {
+        eval("""
+            |import akka.channels._
+            |import ChannelSpec._
+            |new Channels[Parent[TNil], Channel[A, B] :=: Channel[C, D] :=: TNil] {
+            |  createChild(new Channels[Parent[B :-: TNil], TNil])
+            |}
+            """.stripMargin)
+      }.message must include("This actor cannot support a child requiring channels akka.channels.ChannelSpec.B")
+    }
+
+    "have a working selfChannel" in {
+      val ref = ChannelExt(system).actorOf(new Children)
+      ref ! A
+      expectMsg(C)
+    }
+
   }
 
 }
\ No newline at end of file
diff --git a/akka-macros/src/main/scala/akka/channels/Channels.scala b/akka-macros/src/main/scala/akka/channels/Channels.scala
index 4f9b037a0a..19e0bac74b 100644
--- a/akka-macros/src/main/scala/akka/channels/Channels.scala
+++ b/akka-macros/src/main/scala/akka/channels/Channels.scala
@@ -10,11 +10,16 @@ import scala.reflect.macros.Context
 import scala.reflect.runtime.universe.TypeTag
 import scala.reflect.macros.Universe
 import scala.runtime.AbstractPartialFunction
+import akka.actor.Props
 
-trait Channels[P <: Parent[_], C <: ChannelList] extends Actor {
+class Channels[P <: Parent[_], C <: ChannelList: TypeTag] extends Actor {
 
   import Channels._
 
+  def createChild[Pa <: Parent[_], Ch <: ChannelList](factory: Channels[Pa, Ch]): ChannelRef[Ch] = macro createChildImpl[C, Pa, Ch]
+
+  implicit val selfChannel = new ChannelRef[C](self)
+
   /*
    * Warning Ugly Hack Ahead
    * 
@@ -27,7 +32,7 @@ trait Channels[P <: Parent[_], C <: ChannelList] extends Actor {
    */
   private var behavior = List.empty[Recv[Any, ChannelList]]
 
-  def channel[T]: Channels[P, C]#Behaviorist[T, _ <: ChannelList] = macro Channels.channelImpl[T, C, P, ChannelList]
+  def channel[T]: Channels[P, C]#Behaviorist[T, _ <: ChannelList] = macro channelImpl[T, C, P, ChannelList]
 
   protected def _channel[T, Ch <: ChannelList] = new Behaviorist[T, Ch]
   protected class Behaviorist[T, Ch <: ChannelList] {
@@ -87,6 +92,42 @@ object Channels {
     }
   }
 
+  def createChildImpl[C <: ChannelList: c.WeakTypeTag, Pa <: Parent[_]: c.WeakTypeTag, Ch <: ChannelList: c.WeakTypeTag](
+    c: Context {
+      type PrefixType = Channels[_, C]
+    })(factory: c.Expr[Channels[Pa, Ch]]): c.Expr[ChannelRef[Ch]] = {
+
+    import c.universe._
+    if (weakTypeOf[Pa] =:= weakTypeOf[Nothing]) {
+      c.abort(c.enclosingPosition, "Parent argument must not be Nothing")
+    }
+    if (weakTypeOf[Ch] =:= weakTypeOf[Nothing]) {
+      c.abort(c.enclosingPosition, "channel list must not be Nothing")
+    }
+    val missing = missingChannels(c.universe)(weakTypeOf[C], parentChannels(c.universe)(weakTypeOf[Pa]))
+    if (missing.isEmpty) {
+      implicit val t = c.TypeTag[Ch](c.weakTypeOf[Ch])
+      reify(new ChannelRef[Ch](c.prefix.splice.context.actorOf(Props(factory.splice))))
+    } else {
+      c.error(c.enclosingPosition, s"This actor cannot support a child requiring channels ${missing mkString ", "}")
+      reify(null)
+    }
+  }
+
+  /**
+   * get all required channels from a Parent[_]
+   */
+  final def parentChannels(u: Universe)(list: u.Type): List[u.Type] = {
+    import u._
+    def rec(l: u.Type, acc: List[u.Type]): List[u.Type] = l match {
+      case TypeRef(_, _, ch :: tail :: Nil) ⇒ rec(tail, ch :: acc)
+      case _                                ⇒ acc.reverse
+    }
+    list match {
+      case TypeRef(_, _, ch :: Nil) ⇒ rec(ch, Nil)
+    }
+  }
+
   /**
    * find all input channels matching the given message type and return a
    * list of their respective reply channels