content: /*
   * 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.spark.network.netty;
  
  import java.io.File;
  import java.io.FileInputStream;
  
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.SimpleChannelInboundHandler;
  import io.netty.channel.DefaultFileRegion;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.spark.storage.BlockId;
  import org.apache.spark.storage.FileSegment;
  
  class FileServerHandler extends SimpleChannelInboundHandler<String> {
  
    private static final Logger LOG = LoggerFactory.getLogger(FileServerHandler.class.getName());
  
    private final PathResolver pResolver;
  
    FileServerHandler(PathResolver pResolver){
      this.pResolver = pResolver;
    }
  
    @Override
    public void channelRead0(ChannelHandlerContext ctx, String blockIdString) {
      BlockId blockId = BlockId.apply(blockIdString);
      FileSegment fileSegment = pResolver.getBlockLocation(blockId);
      // if getBlockLocation returns null, close the channel
      if (fileSegment == null) {
        //ctx.close();
        return;
      }
      File file = fileSegment.file();
      if (file.exists()) {
        if (!file.isFile()) {
          ctx.write(new FileHeader(0, blockId).buffer());
          ctx.flush();
          return;
        }
        long length = fileSegment.length();
        if (length > Integer.MAX_VALUE || length <= 0) {
          ctx.write(new FileHeader(0, blockId).buffer());
          ctx.flush();
          return;
        }
        int len = (int) length;
        ctx.write((new FileHeader(len, blockId)).buffer());
        try {
          ctx.write(new DefaultFileRegion(new FileInputStream(file)
            .getChannel(), fileSegment.offset(), fileSegment.length()));
        } catch (Exception e) {
            LOG.error("Exception: ", e);
        }
      } else {
        ctx.write(new FileHeader(0, blockId).buffer());
      }
      ctx.flush();
    }
  
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
      LOG.error("Exception: ", cause);
      ctx.close();
    }
  }
  