/*
    *  Licensed to the Apache Software Foundation (ASF) under one
    *  or more contributor license agreements.  See the NOTICE file
    *  distributed with this work for additional information
    *  regarding copyright ownership.  The ASF licenses this file
    *  to you under the Apache License, Version 2.0 (the
    *  "License"); you may not use this file except in compliance
    *  with the License.  You may obtain a copy of the License at
    *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License.
   *
   */
  
  package org.apache.mina.filter.ssl;
  
  import static org.junit.Assert.assertEquals;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.Future;
  
  import javax.net.ssl.SSLException;
  
  import org.apache.mina.core.filterchain.IoFilter.NextFilter;
  import org.apache.mina.core.session.DummySession;
  import org.apache.mina.core.session.IdleStatus;
  import org.apache.mina.core.session.IoSession;
  import org.apache.mina.core.write.DefaultWriteRequest;
  import org.apache.mina.core.write.WriteRequest;
  import org.junit.Before;
  import org.junit.Test;
  
  /**
   * A test for DIRMINA-1019
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  abstract class AbstractNextFilter implements NextFilter {
      public abstract void messageReceived(IoSession session, Object message);
      
      public abstract void filterWrite(IoSession session, WriteRequest writeRequest);
      
      // Following are unimplemented as they aren't used in test
      public void sessionCreated(IoSession session) { }
  
      public void sessionOpened(IoSession session) { }
  
      public void sessionClosed(IoSession session) { }
  
      public void sessionIdle(IoSession session, IdleStatus status) { }
  
      public void exceptionCaught(IoSession session, Throwable cause) { }
  
      public void inputClosed(IoSession session) { }
  
      public void messageSent(IoSession session, WriteRequest writeRequest) { }
  
      public void filterClose(IoSession session) { }
  
      public String toString() {
          return null;
      }
  };
  
  /**
   * A test for DIRMINA-1019
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  public class SslFilterTest {
      SslHandler test_class;
      
      @Before
      public void init() throws SSLException {
          test_class = new SslHandler(null, new DummySession());
      }
      
      @Test
      public void testFlushRaceCondition() {
          final ExecutorService executor = Executors.newFixedThreadPool(1);
          final List<Object> message_received_messages = new ArrayList<>();
          final List<WriteRequest> filter_write_requests = new ArrayList<>();
          
          final AbstractNextFilter write_filter = new AbstractNextFilter()
          {
              @Override
              public void messageReceived(IoSession session, Object message) { }
  
              @Override
              public void filterWrite(IoSession session, WriteRequest writeRequest) {
                  filter_write_requests.add(writeRequest);
              }
         };
         
         AbstractNextFilter receive_filter = new AbstractNextFilter()
         {
             @Override
             public void messageReceived(IoSession session, Object message) {
                 message_received_messages.add(message);
                 
                 // This is where the race condition occurs. If a thread calls SslHandler.scheduleFilterWrite(),
                 // followed by SslHandler.flushScheduledEvents(), the queued event will not be processed as
                 // the current thread owns the SslHandler.sslLock and has already "dequeued" all the queued
                 // filterWriteEventQueue.
                 Future<?> write_scheduler = executor.submit(new Runnable() {
                     public void run() {
                         synchronized(test_class) {
                             test_class.scheduleFilterWrite(write_filter, new DefaultWriteRequest(new byte[] {}));
                             test_class.flushFilterWrite();
                         }
                     }
                 });
                 
                 try {
                     write_scheduler.get();
                 } catch (Exception e) { }
             }
 
             @Override
             public void filterWrite(IoSession session, WriteRequest writeRequest) { }
         };
         
         synchronized(test_class) {
             test_class.scheduleMessageReceived(receive_filter, new byte[] {});
         }
         
         test_class.flushMessageReceived();
 
         assertEquals(1, message_received_messages.size());
         assertEquals(1, filter_write_requests.size());
     }
 }