From 8ce7e73e78dd4d46f823cae356f0e976e7152327 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Thu, 18 Aug 2016 20:47:33 +0200
Subject: [PATCH] Prevent extra peformance hit by fillInStackTrace() when
 create a new annotated connect exception.

Motivation:

To make it easier to debug connect exceptions we create new exceptions which also contain the remote address. For this we basically created a new instance and call setStackTrace(...). When doing this we pay an extra penality because it calls fillInStackTrace() when calling the super constructor.

Modifications:

Create special sub-classes of Exceptions that override the fillInStackTrace() method and so eliminate the overhead.

Result:

Less overhead when "annotate" connect exceptions.
---
 .../io/netty/channel/AbstractChannel.java     | 63 +++++++++++++++----
 1 file changed, 52 insertions(+), 11 deletions(-)

diff --git a/transport/src/main/java/io/netty/channel/AbstractChannel.java b/transport/src/main/java/io/netty/channel/AbstractChannel.java
index 4055677dba..879b4c6441 100644
--- a/transport/src/main/java/io/netty/channel/AbstractChannel.java
+++ b/transport/src/main/java/io/netty/channel/AbstractChannel.java
@@ -939,17 +939,13 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
          */
         protected final Throwable annotateConnectException(Throwable cause, SocketAddress remoteAddress) {
             if (cause instanceof ConnectException) {
-                Throwable newT = new ConnectException(cause.getMessage() + ": " + remoteAddress);
-                newT.setStackTrace(cause.getStackTrace());
-                cause = newT;
-            } else if (cause instanceof NoRouteToHostException) {
-                Throwable newT = new NoRouteToHostException(cause.getMessage() + ": " + remoteAddress);
-                newT.setStackTrace(cause.getStackTrace());
-                cause = newT;
-            } else if (cause instanceof SocketException) {
-                Throwable newT = new SocketException(cause.getMessage() + ": " + remoteAddress);
-                newT.setStackTrace(cause.getStackTrace());
-                cause = newT;
+                return new AnnotatedConnectException((ConnectException) cause, remoteAddress);
+            }
+            if (cause instanceof NoRouteToHostException) {
+                return new AnnotatedNoRouteToHostException((NoRouteToHostException) cause, remoteAddress);
+            }
+            if (cause instanceof SocketException) {
+                return new AnnotatedSocketException((SocketException) cause, remoteAddress);
             }
 
             return cause;
@@ -1062,4 +1058,49 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
             return super.trySuccess();
         }
     }
+
+    private static final class AnnotatedConnectException extends ConnectException {
+
+        private static final long serialVersionUID = 3901958112696433556L;
+
+        AnnotatedConnectException(ConnectException exception, SocketAddress remoteAddress) {
+            super(exception.getMessage() + ": " + remoteAddress);
+            setStackTrace(exception.getStackTrace());
+        }
+
+        @Override
+        public Throwable fillInStackTrace() {
+            return this;
+        }
+    }
+
+    private static final class AnnotatedNoRouteToHostException extends NoRouteToHostException {
+
+        private static final long serialVersionUID = -6801433937592080623L;
+
+        AnnotatedNoRouteToHostException(NoRouteToHostException exception, SocketAddress remoteAddress) {
+            super(exception.getMessage() + ": " + remoteAddress);
+            setStackTrace(exception.getStackTrace());
+        }
+
+        @Override
+        public Throwable fillInStackTrace() {
+            return this;
+        }
+    }
+
+    private static final class AnnotatedSocketException extends SocketException {
+
+        private static final long serialVersionUID = 3896743275010454039L;
+
+        AnnotatedSocketException(SocketException exception, SocketAddress remoteAddress) {
+            super(exception.getMessage() + ": " + remoteAddress);
+            setStackTrace(exception.getStackTrace());
+        }
+
+        @Override
+        public Throwable fillInStackTrace() {
+            return this;
+        }
+    }
 }