Cleanup IPC

main-command/src/main/scala/xsbt/IPC.scala

@@ -10,47 +10,57 @@ package xsbt
 import java.io.{ BufferedReader, BufferedWriter, InputStreamReader, OutputStreamWriter }
 import java.net.{ InetAddress, ServerSocket, Socket }
 
+import scala.annotation.tailrec
 import scala.util.control.NonFatal
 
 object IPC {
   private val portMin = 1025
   private val portMax = 65536
-  private val loopback = InetAddress.getByName(null) // loopback
+  private val loopback = InetAddress.getByName(null)
 
-  def client[T](port: Int)(f: IPC => T): T =
-    ipc(new Socket(loopback, port))(f)
+  def client[T](port: Int)(f: IPC => T): T = ipc(new Socket(loopback, port))(f)
 
   def pullServer[T](f: Server => T): T = {
     val server = makeServer
-    try { f(new Server(server)) } finally { server.close() }
+    try f(new Server(server))
+    finally server.close()
   }
+
   def unmanagedServer: Server = new Server(makeServer)
+
   def makeServer: ServerSocket = {
     val random = new java.util.Random
     def nextPort = random.nextInt(portMax - portMin + 1) + portMin
+
     def createServer(attempts: Int): ServerSocket =
-      if (attempts > 0)
-        try { new ServerSocket(nextPort, 1, loopback) } catch {
-          case NonFatal(_) => createServer(attempts - 1)
-        } else
-        sys.error("Could not connect to socket: maximum attempts exceeded")
+      if (attempts > 0) {
+        try new ServerSocket(nextPort, 1, loopback)
+        catch { case NonFatal(_) => createServer(attempts - 1) }
+      } else sys.error("Could not connect to socket: maximum attempts exceeded")
+
     createServer(10)
   }
+
   def server[T](f: IPC => Option[T]): T = serverImpl(makeServer, f)
+
   def server[T](port: Int)(f: IPC => Option[T]): T =
     serverImpl(new ServerSocket(port, 1, loopback), f)
+
   private def serverImpl[T](server: ServerSocket, f: IPC => Option[T]): T = {
-    def listen(): T = {
+    @tailrec def listen(): T = {
       ipc(server.accept())(f) match {
         case Some(done) => done
         case None       => listen()
       }
     }
 
-    try { listen() } finally { server.close() }
+    try listen()
+    finally server.close()
   }
+
   private def ipc[T](s: Socket)(f: IPC => T): T =
-    try { f(new IPC(s)) } finally { s.close() }
+    try f(new IPC(s))
+    finally s.close()
 
   final class Server private[IPC] (s: ServerSocket) {
     def port = s.getLocalPort
@@ -59,6 +69,7 @@ object IPC {
     def connection[T](f: IPC => T): T = IPC.ipc(s.accept())(f)
   }
 }
+
 final class IPC private (s: Socket) {
   def port = s.getLocalPort
   private val in = new BufferedReader(new InputStreamReader(s.getInputStream))