package org.apache.maven.plugin.surefire.extensions;
   
   /*
    * 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.
   */
  
  import org.apache.maven.plugin.surefire.booterclient.output.NativeStdOutStreamConsumer;
  import org.apache.maven.surefire.api.event.Event;
  import org.apache.maven.surefire.extensions.CloseableDaemonThread;
  import org.apache.maven.surefire.extensions.CommandReader;
  import org.apache.maven.surefire.extensions.EventHandler;
  import org.apache.maven.surefire.extensions.ForkChannel;
  import org.apache.maven.surefire.extensions.ForkNodeArguments;
  import org.apache.maven.surefire.extensions.util.CountdownCloseable;
  import org.apache.maven.surefire.extensions.util.LineConsumerThread;
  
  import javax.annotation.Nonnull;
  import java.io.Closeable;
  import java.io.IOException;
  import java.net.Inet4Address;
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.SocketOption;
  import java.nio.channels.AsynchronousServerSocketChannel;
  import java.nio.channels.AsynchronousSocketChannel;
  import java.nio.channels.ReadableByteChannel;
  import java.nio.channels.WritableByteChannel;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  
  import static java.net.StandardSocketOptions.SO_KEEPALIVE;
  import static java.net.StandardSocketOptions.SO_REUSEADDR;
  import static java.net.StandardSocketOptions.TCP_NODELAY;
  import static java.nio.channels.AsynchronousChannelGroup.withThreadPool;
  import static java.nio.channels.AsynchronousServerSocketChannel.open;
  import static org.apache.maven.surefire.api.util.internal.Channels.newBufferedChannel;
  import static org.apache.maven.surefire.api.util.internal.Channels.newChannel;
  import static org.apache.maven.surefire.api.util.internal.Channels.newInputStream;
  import static org.apache.maven.surefire.api.util.internal.Channels.newOutputStream;
  import static org.apache.maven.surefire.api.util.internal.DaemonThreadFactory.newDaemonThreadFactory;
  
  /**
   * The TCP/IP server accepting only one client connection. The forked JVM connects to the server using the
   * {@link #getForkNodeConnectionString() connection string}.
   * The main purpose of this class is to {@link #connectToClient() conect with tthe client}, bind the
   * {@link #bindCommandReader(CommandReader, WritableByteChannel) command reader} to the internal socket's
   * {@link java.io.InputStream}, and bind the
   * {@link #bindEventHandler(EventHandler, CountdownCloseable, ReadableByteChannel) event handler} writing the event
   * objects to the {@link EventHandler event handler}.
   * <br>
   * The objects {@link WritableByteChannel} and {@link ReadableByteChannel} are forked process streams
   * (standard input and output). Both are ignored in this implementation but they are used in {@link LegacyForkChannel}.
   * <br>
   * The channel is closed after the forked JVM has finished normally or the shutdown hook is executed in the plugin.
   */
  final class SurefireForkChannel extends ForkChannel
  {
      private static final ExecutorService THREAD_POOL = Executors.newCachedThreadPool( newDaemonThreadFactory() );
  
      private final AsynchronousServerSocketChannel server;
      private final String localHost;
      private final int localPort;
      private volatile AsynchronousSocketChannel worker;
      private volatile LineConsumerThread out;
  
      SurefireForkChannel( @Nonnull ForkNodeArguments arguments ) throws IOException
      {
          super( arguments );
          server = open( withThreadPool( THREAD_POOL ) );
          setTrueOptions( SO_REUSEADDR, TCP_NODELAY, SO_KEEPALIVE );
          InetAddress ip = Inet4Address.getLocalHost();
          server.bind( new InetSocketAddress( ip, 0 ), 1 );
          InetSocketAddress localAddress = (InetSocketAddress) server.getLocalAddress();
          localHost = localAddress.getHostString();
          localPort = localAddress.getPort();
      }
  
      @Override
      public void connectToClient() throws IOException
      {
          if ( worker != null )
          {
              throw new IllegalStateException( "already accepted TCP client connection" );
         }
 
         try
         {
             worker = server.accept().get();
         }
         catch ( InterruptedException e )
         {
             throw new IOException( e.getLocalizedMessage(), e );
         }
         catch ( ExecutionException e )
         {
             throw new IOException( e.getLocalizedMessage(), e.getCause() );
         }
     }
 
     @SafeVarargs
     private final void setTrueOptions( SocketOption<Boolean>... options )
         throws IOException
     {
         for ( SocketOption<Boolean> option : options )
         {
             if ( server.supportedOptions().contains( option ) )
             {
                 server.setOption( option, true );
             }
         }
     }
 
     @Override
     public String getForkNodeConnectionString()
     {
         return "tcp://" + localHost + ":" + localPort;
     }
 
     @Override
     public int getCountdownCloseablePermits()
     {
         return 3;
     }
 
     @Override
     public CloseableDaemonThread bindCommandReader( @Nonnull CommandReader commands,
                                                     WritableByteChannel stdIn )
     {
         // dont use newBufferedChannel here - may cause the command is not sent and the JVM hangs
         // only newChannel flushes the message
         // newBufferedChannel does not flush
         WritableByteChannel channel = newChannel( newOutputStream( worker ) );
         return new StreamFeeder( "commands-fork-" + getArguments().getForkChannelId(), channel, commands,
             getArguments().getConsoleLogger() );
     }
 
     @Override
     public CloseableDaemonThread bindEventHandler( @Nonnull EventHandler<Event> eventHandler,
                                                    @Nonnull CountdownCloseable countdownCloseable,
                                                    ReadableByteChannel stdOut )
     {
         out = new LineConsumerThread( "fork-" + getArguments().getForkChannelId() + "-out-thread", stdOut,
             new NativeStdOutStreamConsumer( getArguments().getConsoleLogger() ), countdownCloseable );
         out.start();
 
         ReadableByteChannel channel = newBufferedChannel( newInputStream( worker ) );
         return new EventConsumerThread( "fork-" + getArguments().getForkChannelId() + "-event-thread", channel,
             eventHandler, countdownCloseable, getArguments() );
     }
 
     @Override
     public void close() throws IOException
     {
         //noinspection unused,EmptyTryBlock,EmptyTryBlock
         try ( Closeable c1 = worker; Closeable c2 = server; Closeable c3 = out )
         {
             // only close all channels
         }
     }
 }