From f542ce885c27deba72959a1ae114fdd3a09720d0 Mon Sep 17 00:00:00 2001
From: Patrik Nordwall <patrik.nordwall@gmail.com>
Date: Thu, 9 Mar 2017 17:01:36 +0100
Subject: [PATCH] optimize actor names

---
 .../main/scala/akka/stream/Attributes.scala   | 22 +++++++++-------
 .../impl/PhasedFusingActorMaterializer.scala  | 25 ++++++++-----------
 2 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/akka-stream/src/main/scala/akka/stream/Attributes.scala b/akka-stream/src/main/scala/akka/stream/Attributes.scala
index 41a0de334a..325fb1f449 100644
--- a/akka-stream/src/main/scala/akka/stream/Attributes.scala
+++ b/akka-stream/src/main/scala/akka/stream/Attributes.scala
@@ -170,12 +170,7 @@ final case class Attributes(attributeList: List[Attributes.Attribute] = Nil) {
   /**
    * Extracts Name attributes and concatenates them.
    */
-  def nameLifted: Option[String] = Option(nameOrDefault(null))
-
-  /**
-   * INTERNAL API
-   */
-  def nameOrDefault(default: String = "unknown-operation"): String = {
+  def nameLifted: Option[String] = {
     @tailrec def concatNames(i: Iterator[Attribute], first: String, buf: StringBuilder): String =
       if (i.hasNext)
         i.next() match {
@@ -192,10 +187,19 @@ final case class Attributes(attributeList: List[Attributes.Attribute] = Nil) {
       else if (buf eq null) first
       else buf.toString
 
-    concatNames(attributeList.reverseIterator, null, null) match {
-      case null ⇒ default
-      case some ⇒ some
+    Option(concatNames(attributeList.reverseIterator, null, null))
+  }
+
+  /**
+   * INTERNAL API
+   */
+  def nameOrDefault(default: String = "unnamed"): String = {
+    @tailrec def find(attrs: List[Attribute]): String = attrs match {
+      case Attributes.Name(name) :: _ ⇒ name
+      case _ :: tail                  ⇒ find(tail)
+      case Nil                        ⇒ default
     }
+    find(attributeList)
   }
 
 }
diff --git a/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala b/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala
index db9751089f..bd08427ae3 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala
@@ -28,6 +28,7 @@ import scala.concurrent.ExecutionContextExecutor
 import scala.annotation.tailrec
 import akka.stream.impl.fusing.GraphInterpreter.DownstreamBoundaryStageLogic
 import akka.stream.impl.fusing.GraphInterpreter.UpstreamBoundaryStageLogic
+import akka.util.OptionVal
 
 object PhasedFusingActorMaterializer {
 
@@ -556,6 +557,7 @@ final class GraphStageIsland(
   private val connections = Array.ofDim[Connection](64)
   private var maxConnections = 0
   private var outConnections: List[Connection] = Nil
+  private var fullIslandName: OptionVal[String] = OptionVal.None
 
   val shell = new GraphInterpreterShell(
     connections = null,
@@ -575,6 +577,10 @@ final class GraphStageIsland(
     logic.attributes = attributes
     logics.add(logic)
     logic.stageId = logics.size() - 1
+    fullIslandName match {
+      case OptionVal.Some(_) ⇒ // already set
+      case OptionVal.None    ⇒ fullIslandName = OptionVal.Some(islandName + "-" + logic.attributes.nameOrDefault())
+    }
     matAndLogic
   }
 
@@ -673,23 +679,14 @@ final class GraphStageIsland(
       case _ ⇒
         val props = ActorGraphInterpreter.props(shell)
           .withDispatcher(effectiveSettings.dispatcher)
-        materializer.actorOf(props, fullIslandName)
+        val actorName = fullIslandName match {
+          case OptionVal.Some(n) ⇒ n
+          case OptionVal.None    ⇒ islandName
+        }
+        materializer.actorOf(props, actorName)
     }
   }
 
-  private def fullIslandName: String = {
-    @tailrec def findUsefulName(i: Int): String = {
-      if (i == logics.size) islandName
-      else logics.get(i) match {
-        case _: DownstreamBoundaryStageLogic[_] | _: UpstreamBoundaryStageLogic[_] ⇒
-          findUsefulName(i + 1)
-        case _ ⇒
-          islandName + "-" + logics.get(i).attributes.nameOrDefault()
-      }
-    }
-    findUsefulName(0)
-  }
-
   override def toString: String = "GraphStagePhase"
 }