dart:io | Handle an immediately closed connection in RawSecureServerSocket.

sdk/lib/io/secure_server_socket.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 /**
  * The [SecureServerSocket] is a server socket, providing a stream of high-level
  * [Socket]s.
  *
@@ skipping 194 matching lines @@
 
   /**
    * Closes the socket.
    */
   void close() {
     _closed = true;
     _socket.close();
   }
 
   void _onData(RawSocket connection) {
+    var remotePort;
+    try {
+      remotePort = connection.remotePort;
+    } catch (e) {
+      // If connection is already closed, remotePort throws an exception.
+      // Do nothing - connection is closed.
+      return;
+    }
     _RawSecureSocket.connect(
         connection.address,
-        connection.remotePort,
+        remotePort,
         certificateName,
         is_server: true,
         socket: connection,
         requestClientCertificate: requestClientCertificate,
         requireClientCertificate: requireClientCertificate)
     .then((RawSecureSocket secureConnection) {
       if (_closed) {
         secureConnection.close();
       } else {
         _controller.add(secureConnection);
@@ skipping 26 matching lines @@
       _subscription = _socket.listen(_onData,
                                      onDone: _onDone,
                                      onError: _onError);
     } else {
       close();
     }
   }
 }