first step: sanitize ActorPath interface

- remove references to ActorSystem
- make ChildActorPath light-weight (name & parent plus tailrec methods
  for traversing towards root, e.g. toString)
- string rep is full URI always (akka://system-name@host:port/user/bla)

akka-actor-tests/src/test/scala/akka/actor/ActorRefSpec.scala

@@ -284,8 +284,8 @@ class ActorRefSpec extends AkkaSpec {
       val baos = new ByteArrayOutputStream(8192 * 32)
       val out = new ObjectOutputStream(baos)
 
-      val addr = system.asInstanceOf[ActorSystemImpl].provider.rootPath.remoteAddress
-      val serialized = SerializedActorRef(addr.hostname, addr.port, "/this/path/does/not/exist")
+      val addr = system.asInstanceOf[ActorSystemImpl].provider.rootPath.address
+      val serialized = SerializedActorRef(addr.hostPort, 0, "/this/path/does/not/exist")
 
       out.writeObject(serialized)
 

akka-actor/src/main/scala/akka/actor/ActorPath.scala

@@ -1,10 +1,8 @@
 /**
  *  Copyright (C) 2009-2011 Typesafe Inc. <http://www.typesafe.com>
  */
-
 package akka.actor
-
-import akka.remote.RemoteAddress
+import scala.annotation.tailrec
 
 object ActorPath {
   final val separator = "/"
@@ -60,9 +58,10 @@ object ActorPath {
  */
 trait ActorPath {
   /**
-   * The RemoteAddress for this path.
+   * The Address under which this path can be reached; walks up the tree to
+   * the RootActorPath.
    */
-  def remoteAddress: RemoteAddress
+  def address: Address = root.address
 
   /**
    * The name of the actor that this path refers to.
@@ -84,49 +83,64 @@ trait ActorPath {
    */
   def /(child: Iterable[String]): ActorPath = (this /: child)(_ / _)
 
-  /**
-   * String representation of this path. Different from toString for root path.
-   */
-  def string: String
-
   /**
    * Sequence of names for this path.
    */
-  def path: Iterable[String]
+  def pathElements: Iterable[String]
 
   /**
-   * Is this the root path?
+   * Walk up the tree to obtain and return the RootActorPath.
    */
-  def isRoot: Boolean
+  def root: RootActorPath
 }
 
-class RootActorPath(val remoteAddress: RemoteAddress) extends ActorPath {
-
-  def name: String = "/"
+/**
+ * Root of the hierarchy of ActorPaths. There is exactly root per ActorSystem
+ * and node (for remote-enabled or clustered systems).
+ */
+class RootActorPath(override val address: Address, val name: String = ActorPath.separator) extends ActorPath {
 
   def parent: ActorPath = this
 
-  def /(child: String): ActorPath = new ChildActorPath(remoteAddress, this, child)
+  def root: RootActorPath = this
 
-  def string: String = ""
+  def /(child: String): ActorPath = new ChildActorPath(this, child)
 
-  def path: Iterable[String] = Iterable.empty
+  def pathElements: Iterable[String] = Iterable.empty
 
-  def isRoot: Boolean = true
-
-  override def toString = ActorPath.separator
+  override val toString = address + ActorPath.separator
 }
 
-class ChildActorPath(val remoteAddress: RemoteAddress, val parent: ActorPath, val name: String) extends ActorPath {
+class ChildActorPath(val parent: ActorPath, val name: String) extends ActorPath {
 
-  def /(child: String): ActorPath = new ChildActorPath(remoteAddress, this, child)
+  def /(child: String): ActorPath = new ChildActorPath(this, child)
 
-  def string: String = parent.string + ActorPath.separator + name
+  def pathElements: Iterable[String] = {
+    @tailrec
+    def rec(p: ActorPath, acc: List[String]): Iterable[String] = p match {
+      case r: RootActorPath ⇒ acc
+      case _                ⇒ rec(p.parent, p.name :: acc)
+    }
+    rec(this, Nil)
+  }
 
-  def path: Iterable[String] = parent.path ++ Iterable(name)
+  def root = {
+    @tailrec
+    def rec(p: ActorPath): RootActorPath = p match {
+      case r: RootActorPath ⇒ r
+      case _                ⇒ rec(p.parent)
+    }
+    rec(this)
+  }
 
-  def isRoot: Boolean = false
-
-  override def toString = string
+  override def toString = {
+    @tailrec
+    def rec(p: ActorPath, s: String): String = p match {
+      case r: RootActorPath ⇒ r + s
+      case _ if s.isEmpty   ⇒ rec(p.parent, name)
+      case _                ⇒ rec(p.parent, p.name + ActorPath.separator + s)
+    }
+    rec(this, "")
+  }
 }
 

akka-actor/src/main/scala/akka/actor/ActorRef.scala

@@ -303,10 +303,12 @@ trait ScalaActorRef { ref: ActorRef ⇒
 /**
  * Memento pattern for serializing ActorRefs transparently
  */
-
+// FIXME: remove and replace by ActorPath.toString
 case class SerializedActorRef(hostname: String, port: Int, path: String) {
   import akka.serialization.Serialization.system
 
+  // FIXME this is broken, but see above
+  def this(address: Address, path: String) = this(address.hostPort, 0, path)
   def this(remoteAddress: RemoteAddress, path: String) = this(remoteAddress.hostname, remoteAddress.port, path)
   def this(remoteAddress: InetSocketAddress, path: String) = this(remoteAddress.getAddress.getHostAddress, remoteAddress.getPort, path) //TODO FIXME REMOVE
 

akka-actor/src/main/scala/akka/actor/ActorRefProvider.scala

@@ -130,7 +130,7 @@ trait ActorRefFactory {
 
   def actorOf(creator: UntypedActorFactory): ActorRef = actorOf(Props(() ⇒ creator.create()))
 
-  def actorFor(path: ActorPath): Option[ActorRef] = actorFor(path.path)
+  def actorFor(path: ActorPath): Option[ActorRef] = actorFor(path.pathElements)
 
   def actorFor(path: String): Option[ActorRef] = actorFor(ActorPath.split(path))
 
@@ -357,7 +357,7 @@ class LocalActorRefProvider(
   }
 
   private[akka] def deserialize(actor: SerializedActorRef): Option[ActorRef] = actorFor(ActorPath.split(actor.path))
-  private[akka] def serialize(actor: ActorRef): SerializedActorRef = new SerializedActorRef(rootPath.remoteAddress, actor.path.toString)
+  private[akka] def serialize(actor: ActorRef): SerializedActorRef = new SerializedActorRef(rootPath.address, actor.path.toString)
 
   private[akka] def createDeathWatch(): DeathWatch = new LocalDeathWatch
 

akka-actor/src/main/scala/akka/actor/Address.scala

@@ -0,0 +1,21 @@
+/**
+ *  Copyright (C) 2009-2011 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.actor
+
+/**
+ * The address specifies the physical location under which an Actor can be
+ * reached. Examples are local addresses, identified by the ActorSystem’s
+ * name, and remote addresses, identified by protocol, host and port.
+ */
+abstract class Address {
+  def protocol: String
+  def hostPort: String
+  @transient
+  override lazy val toString = protocol + "://" + hostPort
+}
+
+case class LocalAddress(systemName: String) extends Address {
+  def protocol = "akka"
+  def hostPort = systemName
+}

akka-actor/src/main/scala/akka/remote/RemoteInterface.scala

@@ -28,10 +28,10 @@ object RemoteAddress {
 
 object LocalOnly extends RemoteAddress(0, "local")
 
-case class RemoteAddress private[akka] (port: Int, hostname: String) {
+case class RemoteAddress private[akka] (port: Int, hostname: String) extends Address {
+  def protocol = "akka"
   @transient
-  override lazy val toString = "" + hostname + ":" + port
-
+  lazy val hostPort = hostname + ":" + port
 }
 
 class RemoteException(message: String) extends AkkaException(message)

akka-durable-mailboxes/akka-mailboxes-common/src/main/scala/akka/actor/mailbox/DurableMailbox.scala

@@ -41,7 +41,7 @@ abstract class DurableMailbox(owner: ActorCell) extends Mailbox(owner) with Defa
 
   def system = owner.system
   def ownerPath = owner.self.path
-  val ownerPathString = ownerPath.path.mkString("/")
+  val ownerPathString = ownerPath.pathElements.mkString("/")
   val name = "mailbox_" + Name.replaceAllIn(ownerPathString, "_")
 
 }

akka-remote/src/main/scala/akka/remote/Gossiper.scala

@@ -108,7 +108,7 @@ class Gossiper(remote: Remote) {
   private val connectionManager = new RemoteConnectionManager(system, remote, Map.empty[RemoteAddress, ActorRef])
   private val seeds = Set(address) // FIXME read in list of seeds from config
 
-  private val address = system.asInstanceOf[ActorSystemImpl].provider.rootPath.remoteAddress
+  private val address = remote.remoteAddress
   private val nodeFingerprint = address.##
 
   private val random = SecureRandom.getInstance("SHA1PRNG")

akka-remote/src/main/scala/akka/remote/Remote.scala

@@ -71,22 +71,21 @@ class Remote(val system: ActorSystemImpl, val nodename: String) {
 
   lazy val eventStream = new NetworkEventStream(system)
 
-  lazy val server: RemoteSupport = {
-    val remote = new akka.remote.netty.NettyRemoteSupport(system)
+  @volatile
+  private var _server: RemoteSupport = _
+  def server = _server
+
+  def start(): Unit = {
+    val remote = new akka.remote.netty.NettyRemoteSupport(system, this)
     remote.start() //TODO FIXME Any application loader here?
 
     system.eventStream.subscribe(eventStream.sender, classOf[RemoteLifeCycleEvent])
     system.eventStream.subscribe(remoteClientLifeCycleHandler, classOf[RemoteLifeCycleEvent])
 
-    // TODO actually register this provider in system in remote mode
-    //provider.register(ActorRefProvider.RemoteProvider, new RemoteActorRefProvider)
-    remote
-  }
+    _server = remote
 
-  def start(): Unit = {
-    val serverAddress = server.system.asInstanceOf[ActorSystemImpl].provider.rootPath.remoteAddress //Force init of server
     val daemonAddress = remoteDaemon.address //Force init of daemon
-    log.info("Starting remote server on [{}] and starting remoteDaemon with address [{}]", serverAddress, daemonAddress)
+    log.info("Starting remote server on [{}] and starting remoteDaemon with address [{}]", remoteAddress, daemonAddress)
   }
 }
 

akka-remote/src/main/scala/akka/remote/RemoteActorRefProvider.scala

@@ -102,7 +102,7 @@ class RemoteActorRefProvider(
                 //   case FailureDetectorType.Custom(implClass)              ⇒ FailureDetector.createCustomFailureDetector(implClass)
                 // }
 
-                def isReplicaNode: Boolean = remoteAddresses exists { _ == rootPath.remoteAddress }
+                def isReplicaNode: Boolean = remoteAddresses exists { _ == remote.remoteAddress }
 
                 //system.eventHandler.debug(this, "%s: Deploy Remote Actor with address [%s] connected to [%s]: isReplica(%s)".format(system.defaultAddress, address, remoteAddresses.mkString, isReplicaNode))
 
@@ -204,10 +204,10 @@ class RemoteActorRefProvider(
 
   private[akka] def deserialize(actor: SerializedActorRef): Option[ActorRef] = {
     val remoteAddress = RemoteAddress(actor.hostname, actor.port)
-    if (optimizeLocalScoped_? && remoteAddress == rootPath.remoteAddress) {
+    if (optimizeLocalScoped_? && remoteAddress == remote.remoteAddress) {
       local.actorFor(ActorPath.split(actor.path))
     } else {
-      log.debug("{}: Creating RemoteActorRef with address [{}] connected to [{}]", rootPath.remoteAddress, actor.path, remoteAddress)
+      log.debug("{}: Creating RemoteActorRef with address [{}] connected to [{}]", remote.remoteAddress, actor.path, remoteAddress)
       Some(RemoteActorRef(remote.system.provider, remote.server, remoteAddress, rootPath / ActorPath.split(actor.path), None)) //Should it be None here
     }
   }

akka-remote/src/main/scala/akka/remote/netty/NettyRemoteSupport.scala

@@ -141,7 +141,7 @@ class ActiveRemoteClient private[akka] (
 
   def currentChannel = connection.getChannel
 
-  private val senderRemoteAddress = remoteSupport.system.asInstanceOf[ActorSystemImpl].provider.rootPath.remoteAddress
+  private val senderRemoteAddress = remoteSupport.remote.remoteAddress
 
   /**
    * Connect to remote server.
@@ -355,7 +355,7 @@ class ActiveRemoteClientHandler(
 /**
  * Provides the implementation of the Netty remote support
  */
-class NettyRemoteSupport(_system: ActorSystem) extends RemoteSupport(_system) with RemoteMarshallingOps {
+class NettyRemoteSupport(_system: ActorSystem, val remote: Remote) extends RemoteSupport(_system) with RemoteMarshallingOps {
   val log = Logging(system, "NettyRemoteSupport")
 
   val serverSettings = RemoteExtension(system).settings.serverSettings
@@ -458,7 +458,7 @@ class NettyRemoteSupport(_system: ActorSystem) extends RemoteSupport(_system) wi
 
   def name = currentServer.get match {
     case Some(server) ⇒ server.name
-    case None         ⇒ "Non-running NettyRemoteServer@" + system.asInstanceOf[ActorSystemImpl].provider.rootPath.remoteAddress
+    case None         ⇒ "Non-running NettyRemoteServer@" + remote.remoteAddress
   }
 
   private val _isRunning = new Switch(false)
@@ -493,7 +493,7 @@ class NettyRemoteServer(val remoteSupport: NettyRemoteSupport, val loader: Optio
   val log = Logging(remoteSupport.system, "NettyRemoteServer")
   import remoteSupport.serverSettings._
 
-  val address = remoteSupport.system.asInstanceOf[ActorSystemImpl].provider.rootPath.remoteAddress
+  val address = remoteSupport.remote.remoteAddress
 
   val name = "NettyRemoteServer@" + address