/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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 io.netty.example.socksproxy;
  
  import io.netty.buffer.Unpooled;
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.util.ReferenceCountUtil;
  
  public final class RelayHandler extends ChannelInboundHandlerAdapter {
  
      private final Channel relayChannel;
  
      public RelayHandler(Channel relayChannel) {
          this.relayChannel = relayChannel;
      }
  
      @Override
      public void channelActive(ChannelHandlerContext ctx) {
          ctx.writeAndFlush(Unpooled.EMPTY_BUFFER);
      }
  
      @Override
      public void channelRead(ChannelHandlerContext ctx, Object msg) {
          if (relayChannel.isActive()) {
              relayChannel.writeAndFlush(msg);
          } else {
              ReferenceCountUtil.release(msg);
          }
      }
  
      @Override
      public void channelInactive(ChannelHandlerContext ctx) {
          if (relayChannel.isActive()) {
              SocksServerUtils.closeOnFlush(relayChannel);
          }
      }
  
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
          cause.printStackTrace();
          ctx.close();
      }
  }