//
   //  ========================================================================
   //  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.websocket.common.io.payload;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  
  import org.eclipse.jetty.util.BufferUtil;
  import org.eclipse.jetty.util.Utf8Appendable;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.websocket.api.BadPayloadException;
  import org.eclipse.jetty.websocket.api.extensions.Frame;
  
  /**
   * Used to perform validation of UTF8 payload contents (for fast-fail reasons)
   */
  public class UTF8Validator extends Utf8Appendable implements PayloadProcessor
  {
      private static class EmptyAppender implements Appendable
      {
          private int length = 0;
  
          @Override
          public Appendable append(char c) throws IOException
          {
              length++;
              return this;
          }
  
          @Override
          public Appendable append(CharSequence csq) throws IOException
          {
              length += csq.length();
              return this;
          }
  
          @Override
          public Appendable append(CharSequence csq, int start, int end) throws IOException
          {
              length += (end - start);
              return this;
          }
  
          public int getLength()
          {
              return length;
          }
      }
  
      private static final Logger LOG = Log.getLogger(UTF8Validator.class);
  
      private EmptyAppender buffer;
  
      public UTF8Validator()
      {
          super(new EmptyAppender());
          this.buffer = (EmptyAppender)_appendable;
      }
  
      @Override
      public int length()
      {
          return this.buffer.getLength();
      }
  
      @Override
      public void process(ByteBuffer payload)
      {
          if (LOG.isDebugEnabled())
          {
              LOG.debug("Payload: {}",BufferUtil.toDetailString(payload));
          }
  
          if ((payload == null) || (payload.remaining() <= 0))
          {
              return;
          }
  
          try
          {
              append(payload.slice());
          }
         catch (NotUtf8Exception e)
         {
             throw new BadPayloadException(e);
         }
     }
 
     @Override
     public void reset(Frame frame)
     {
         /* do nothing */
     }
 }