Add AbstractUnsafe.annotateConnectException()

Motivation:

JDK's exception messages triggered by a connection attempt failure do
not contain the related remote address in its message.  We currently
append the remote address to ConnectException's message, but I found
that we need to cover more exception types such as SocketException.

Modifications:

- Add AbstractUnsafe.annotateConnectException() to de-duplicate the
  code that appends the remote address

Result:

- Less duplication
- A transport implementor can annotate connection attempt failure
  message more easily

transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollSocketChannel.java

@@ -37,7 +37,6 @@
 import io.netty.util.internal.StringUtil;
 
 import java.io.IOException;
-import java.net.ConnectException;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.nio.ByteBuffer;
@@ -549,13 +548,8 @@ public void operationComplete(ChannelFuture future) throws Exception {
                     });
                 }
             } catch (Throwable t) {
-                if (t instanceof ConnectException) {
-                    Throwable newT = new ConnectException(t.getMessage() + ": " + remoteAddress);
-                    newT.setStackTrace(t.getStackTrace());
-                    t = newT;
-                }
                 closeIfClosed();
-                promise.tryFailure(t);
+                promise.tryFailure(annotateConnectException(t, remoteAddress));
             }
         }
 
@@ -607,13 +601,7 @@ private void finishConnect() {
                 }
                 fulfillConnectPromise(connectPromise, wasActive);
             } catch (Throwable t) {
-                if (t instanceof ConnectException) {
-                    Throwable newT = new ConnectException(t.getMessage() + ": " + requestedRemoteAddress);
-                    newT.setStackTrace(t.getStackTrace());
-                    t = newT;
-                }
-
-                fulfillConnectPromise(connectPromise, t);
+                fulfillConnectPromise(connectPromise, annotateConnectException(t, requestedRemoteAddress));
             } finally {
                 if (!connectStillInProgress) {
                     // Check for null as the connectTimeoutFuture is only created if a connectTimeoutMillis > 0 is used

transport/src/main/java/io/netty/channel/AbstractChannel.java

@@ -25,8 +25,11 @@
 import io.netty.util.internal.logging.InternalLoggerFactory;
 
 import java.io.IOException;
+import java.net.ConnectException;
 import java.net.InetSocketAddress;
+import java.net.NoRouteToHostException;
 import java.net.SocketAddress;
+import java.net.SocketException;
 import java.nio.channels.ClosedChannelException;
 import java.nio.channels.NotYetConnectedException;
 import java.util.concurrent.RejectedExecutionException;
@@ -810,6 +813,27 @@ private void invokeLater(Runnable task) {
                 logger.warn("Can't invoke task later as EventLoop rejected it", e);
             }
         }
+
+        /**
+         * Appends the remote address to the message of the exceptions caused by connection attempt failure.
+         */
+        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 cause;
+        }
     }
 
     /**

transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java

@@ -34,7 +34,6 @@
 import io.netty.util.internal.logging.InternalLoggerFactory;
 
 import java.io.IOException;
-import java.net.ConnectException;
 import java.net.SocketAddress;
 import java.nio.channels.CancelledKeyException;
 import java.nio.channels.SelectableChannel;
@@ -233,12 +232,7 @@ public void operationComplete(ChannelFuture future) throws Exception {
                     });
                 }
             } catch (Throwable t) {
-                if (t instanceof ConnectException) {
-                    Throwable newT = new ConnectException(t.getMessage() + ": " + remoteAddress);
-                    newT.setStackTrace(t.getStackTrace());
-                    t = newT;
-                }
-                promise.tryFailure(t);
+                promise.tryFailure(annotateConnectException(t, remoteAddress));
                 closeIfClosed();
             }
         }
@@ -287,13 +281,7 @@ public final void finishConnect() {
                 doFinishConnect();
                 fulfillConnectPromise(connectPromise, wasActive);
             } catch (Throwable t) {
-                if (t instanceof ConnectException) {
-                    Throwable newT = new ConnectException(t.getMessage() + ": " + requestedRemoteAddress);
-                    newT.setStackTrace(t.getStackTrace());
-                    t = newT;
-                }
-
-                fulfillConnectPromise(connectPromise, t);
+                fulfillConnectPromise(connectPromise, annotateConnectException(t, requestedRemoteAddress));
             } finally {
                 // Check for null as the connectTimeoutFuture is only created if a connectTimeoutMillis > 0 is used
                 // See https://github.com/netty/netty/issues/1770

transport/src/main/java/io/netty/channel/oio/AbstractOioChannel.java

@@ -21,7 +21,6 @@
 import io.netty.channel.EventLoop;
 import io.netty.channel.ThreadPerChannelEventLoop;
 
-import java.net.ConnectException;
 import java.net.SocketAddress;
 
 /**
@@ -75,12 +74,7 @@ public void connect(
                     pipeline().fireChannelActive();
                 }
             } catch (Throwable t) {
-                if (t instanceof ConnectException) {
-                    Throwable newT = new ConnectException(t.getMessage() + ": " + remoteAddress);
-                    newT.setStackTrace(t.getStackTrace());
-                    t = newT;
-                }
-                safeSetFailure(promise, t);
+                safeSetFailure(promise, annotateConnectException(t, remoteAddress));
                 closeIfClosed();
             }
         }