//
   //  ========================================================================
   //  Copyright (c) 1995-2014 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.server;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.ByteBuffer;
  import java.nio.channels.ReadableByteChannel;
  import java.nio.channels.WritePendingException;
  import java.util.concurrent.atomic.AtomicReference;
  import javax.servlet.RequestDispatcher;
  import javax.servlet.ServletOutputStream;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.WriteListener;
  
  import org.eclipse.jetty.http.HttpContent;
  import org.eclipse.jetty.io.EofException;
  import org.eclipse.jetty.util.BufferUtil;
  import org.eclipse.jetty.util.Callback;
  import org.eclipse.jetty.util.IteratingCallback;
  import org.eclipse.jetty.util.IteratingNestedCallback;
  import org.eclipse.jetty.util.SharedBlockingCallback;
  import org.eclipse.jetty.util.SharedBlockingCallback.Blocker;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  
  /**
   * <p>{@link HttpOutput} implements {@link ServletOutputStream}
   * as required by the Servlet specification.</p>
   * <p>{@link HttpOutput} buffers content written by the application until a
   * further write will overflow the buffer, at which point it triggers a commit
   * of the response.</p>
   * <p>{@link HttpOutput} can be closed and reopened, to allow requests included
   * via {@link RequestDispatcher#include(ServletRequest, ServletResponse)} to
   * close the stream, to be reopened after the inclusion ends.</p>
   */
  public class HttpOutput extends ServletOutputStream implements Runnable
  {
      private static Logger LOG = Log.getLogger(HttpOutput.class);
      private final HttpChannel<?> _channel;
      private final SharedBlockingCallback _writeblock=new SharedBlockingCallback()
      {
          @Override
          protected long getIdleTimeout()
          {
              return _channel.getIdleTimeout();
          }
      };
      private long _written;
      private ByteBuffer _aggregate;
      private int _bufferSize;
      private int _commitSize;
      private WriteListener _writeListener;
      private volatile Throwable _onError;
  
      /*
      ACTION             OPEN       ASYNC      READY      PENDING       UNREADY       CLOSED
      -----------------------------------------------------------------------------------------------------
      setWriteListener() READY->owp ise        ise        ise           ise           ise
      write()            OPEN       ise        PENDING    wpe           wpe           eof
      flush()            OPEN       ise        PENDING    wpe           wpe           eof
      close()            CLOSED     CLOSED     CLOSED     CLOSED        wpe           CLOSED
      isReady()          OPEN:true  READY:true READY:true UNREADY:false UNREADY:false CLOSED:true
      write completed    -          -          -          ASYNC         READY->owp    -
      
      */
      enum OutputState { OPEN, ASYNC, READY, PENDING, UNREADY, ERROR, CLOSED }
      private final AtomicReference<OutputState> _state=new AtomicReference<>(OutputState.OPEN);
  
      public HttpOutput(HttpChannel<?> channel)
      {
          _channel = channel;
          HttpConfiguration config = channel.getHttpConfiguration();
          _bufferSize = config.getOutputBufferSize();
          _commitSize = config.getOutputAggregationSize();
      }
      
      public HttpChannel<?> getHttpChannel()
      {
          return _channel;
      }
      
     public boolean isWritten()
     {
         return _written > 0;
     }
 
     public long getWritten()
     {
         return _written;
     }
 
     public void reset()
     {
         _written = 0;
         reopen();
     }
 
     public void reopen()
     {
         _state.set(OutputState.OPEN);
     }
 
     public boolean isAllContentWritten()
     {
         return _channel.getResponse().isAllContentWritten(_written);
     }
 
     protected Blocker acquireWriteBlockingCallback() throws IOException
     {
         return _writeblock.acquire();
     }
     
     protected void write(ByteBuffer content, boolean complete) throws IOException
     {
         try (Blocker blocker=_writeblock.acquire())
         {        
             write(content,complete,blocker);
             blocker.block();
         }
     }
     
     protected void write(ByteBuffer content, boolean complete, Callback callback)
     {
         _channel.write(content,complete,callback);
     }
     
     @Override
     public void close()
     {
         loop: while(true)
         {
             OutputState state=_state.get();
             switch (state)
             {
                 case CLOSED:
                     break loop;
                     
                 case UNREADY:
                     if (_state.compareAndSet(state,OutputState.ERROR))
                         _writeListener.onError(_onError==null?new EofException("Async close"):_onError);
                     continue;
                     
                 default:
                     if (_state.compareAndSet(state,OutputState.CLOSED))
                     {
                         try
                         {
                             write(BufferUtil.hasContent(_aggregate)?_aggregate:BufferUtil.EMPTY_BUFFER,!_channel.getResponse().isIncluding());
                         }
                         catch(IOException e)
                         {
                             LOG.debug(e);
                             _channel.abort();
                         }
                         releaseBuffer();
                         return;
                     }
             }
         }
     }
 
     /* Called to indicated that the output is already closed (write with last==true performed) and the state needs to be updated to match */
     void closed()
     {
         loop: while(true)
         {
             OutputState state=_state.get();
             switch (state)
             {
                 case CLOSED:
                     break loop;
                     
                 case UNREADY:
                     if (_state.compareAndSet(state,OutputState.ERROR))
                         _writeListener.onError(_onError==null?new EofException("Async closed"):_onError);
                     continue;
                     
                 default:
                     if (_state.compareAndSet(state,OutputState.CLOSED))
                     {
                         try
                         {
                             _channel.getResponse().closeOutput();
                         }
                         catch(IOException e)
                         {
                             LOG.debug(e);
                             _channel.abort();
                         }
                         releaseBuffer();
                         return;
                     }
             }
         }
     }
 
     private void releaseBuffer()
     {
         if (_aggregate != null)
         {
             _channel.getConnector().getByteBufferPool().release(_aggregate);
             _aggregate = null;
         }
     }
 
     public boolean isClosed()
     {
         return _state.get()==OutputState.CLOSED;
     }
 
     @Override
     public void flush() throws IOException
     {
         while(true)
         {
             switch(_state.get())
             {
                 case OPEN:
                     write(BufferUtil.hasContent(_aggregate)?_aggregate:BufferUtil.EMPTY_BUFFER, false);
                     return;
 
                 case ASYNC:
                     throw new IllegalStateException("isReady() not called");
 
                 case READY:
                     if (!_state.compareAndSet(OutputState.READY, OutputState.PENDING))
                         continue;
                     new AsyncFlush().iterate();
                     return;
 
                 case PENDING:
                 case UNREADY:
                     throw new WritePendingException();
 
                 case ERROR:
                     throw new EofException(_onError);
                     
                 case CLOSED:
                     return;
             }
             break;
         }
     }
 
 
     @Override
     public void write(byte[] b, int off, int len) throws IOException
     {
         _written+=len;
         boolean complete=_channel.getResponse().isAllContentWritten(_written);
 
         // Async or Blocking ?
         while(true)
         {
             switch(_state.get())
             {
                 case OPEN:
                     // process blocking below
                     break;
 
                 case ASYNC:
                     throw new IllegalStateException("isReady() not called");
 
                 case READY:
                     if (!_state.compareAndSet(OutputState.READY, OutputState.PENDING))
                         continue;
 
                     // Should we aggregate?
                     if (!complete && len<=_commitSize)
                     {
                         if (_aggregate == null)
                             _aggregate = _channel.getByteBufferPool().acquire(getBufferSize(), false);
 
                         // YES - fill the aggregate with content from the buffer
                         int filled = BufferUtil.fill(_aggregate, b, off, len);
 
                         // return if we are not complete, not full and filled all the content
                         if (filled==len && !BufferUtil.isFull(_aggregate))
                         {
                             if (!_state.compareAndSet(OutputState.PENDING, OutputState.ASYNC))
                                 throw new IllegalStateException();
                             return;
                         }
 
                         // adjust offset/length
                         off+=filled;
                         len-=filled;
                     }
 
                     // Do the asynchronous writing from the callback
                     new AsyncWrite(b,off,len,complete).iterate();
                     return;
 
                 case PENDING:
                 case UNREADY:
                     throw new WritePendingException();
 
                 case ERROR:
                     throw new EofException(_onError);
                     
                 case CLOSED:
                     throw new EofException("Closed");
             }
             break;
         }
 
 
         // handle blocking write
 
         // Should we aggregate?
         int capacity = getBufferSize();
         if (!complete && len<=_commitSize)
         {
             if (_aggregate == null)
                 _aggregate = _channel.getByteBufferPool().acquire(capacity, false);
 
             // YES - fill the aggregate with content from the buffer
             int filled = BufferUtil.fill(_aggregate, b, off, len);
 
             // return if we are not complete, not full and filled all the content
             if (filled==len && !BufferUtil.isFull(_aggregate))
                 return;
 
             // adjust offset/length
             off+=filled;
             len-=filled;
         }
 
         // flush any content from the aggregate
         if (BufferUtil.hasContent(_aggregate))
         {
             write(_aggregate, complete && len==0);
 
             // should we fill aggregate again from the buffer?
             if (len>0 && !complete && len<=_commitSize)
             {
                 BufferUtil.append(_aggregate, b, off, len);
                 return;
             }
         }
 
         // write any remaining content in the buffer directly
         if (len>0)
         {
             ByteBuffer wrap = ByteBuffer.wrap(b, off, len);
             ByteBuffer view = wrap.duplicate();
 
             // write a buffer capacity at a time to avoid JVM pooling large direct buffers
             // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6210541
             while (len>getBufferSize())
             {
                 int p=view.position();
                 int l=p+getBufferSize();
                 view.limit(p+getBufferSize());
                 write(view,false);
                 len-=getBufferSize();
                 view.limit(l+Math.min(len,getBufferSize()));
                 view.position(l);
             }
             write(view,complete);
         }
         else if (complete)
             write(BufferUtil.EMPTY_BUFFER,complete);
 
         if (complete)
             closed();
 
     }
 
     public void write(ByteBuffer buffer) throws IOException
     {
         _written+=buffer.remaining();
         boolean complete=_channel.getResponse().isAllContentWritten(_written);
 
         // Async or Blocking ?
         while(true)
         {
             switch(_state.get())
             {
                 case OPEN:
                     // process blocking below
                     break;
 
                 case ASYNC:
                     throw new IllegalStateException("isReady() not called");
 
                 case READY:
                     if (!_state.compareAndSet(OutputState.READY, OutputState.PENDING))
                         continue;
 
                     // Do the asynchronous writing from the callback
                     new AsyncWrite(buffer,complete).iterate();
                     return;
 
                 case PENDING:
                 case UNREADY:
                     throw new WritePendingException();
 
                 case ERROR:
                     throw new EofException(_onError);
                     
                 case CLOSED:
                     throw new EofException("Closed");
             }
             break;
         }
 
 
         // handle blocking write
         int len=BufferUtil.length(buffer);
 
         // flush any content from the aggregate
         if (BufferUtil.hasContent(_aggregate))
             write(_aggregate, complete && len==0);
 
         // write any remaining content in the buffer directly
         if (len>0)
             write(buffer, complete);
         else if (complete)
             write(BufferUtil.EMPTY_BUFFER,complete);
 
         if (complete)
             closed();
     }
 
     @Override
     public void write(int b) throws IOException
     {
         _written+=1;
         boolean complete=_channel.getResponse().isAllContentWritten(_written);
 
         // Async or Blocking ?
         while(true)
         {
             switch(_state.get())
             {
                 case OPEN:
                     if (_aggregate == null)
                         _aggregate = _channel.getByteBufferPool().acquire(getBufferSize(), false);
                     BufferUtil.append(_aggregate, (byte)b);
 
                     // Check if all written or full
                     if (complete || BufferUtil.isFull(_aggregate))
                     {
                         try(Blocker blocker=_writeblock.acquire())
                         {
                             write(_aggregate, complete, blocker);
                             blocker.block();
                         }
                         if (complete)
                             closed();
                     }
                     break;
 
                 case ASYNC:
                     throw new IllegalStateException("isReady() not called");
 
                 case READY:
                     if (!_state.compareAndSet(OutputState.READY, OutputState.PENDING))
                         continue;
 
                     if (_aggregate == null)
                         _aggregate = _channel.getByteBufferPool().acquire(getBufferSize(), false);
                     BufferUtil.append(_aggregate, (byte)b);
 
                     // Check if all written or full
                     if (!complete && !BufferUtil.isFull(_aggregate))
                     {
                         if (!_state.compareAndSet(OutputState.PENDING, OutputState.ASYNC))
                             throw new IllegalStateException();
                         return;
                     }
 
                     // Do the asynchronous writing from the callback
                     new AsyncFlush().iterate();
                     return;
 
                 case PENDING:
                 case UNREADY:
                     throw new WritePendingException();
 
                 case ERROR:
                     throw new EofException(_onError);
                     
                 case CLOSED:
                     throw new EofException("Closed");
             }
             break;
         }
     }
 
     @Override
     public void print(String s) throws IOException
     {
         if (isClosed())
             throw new IOException("Closed");
 
         write(s.getBytes(_channel.getResponse().getCharacterEncoding()));
     }
 
     /* ------------------------------------------------------------ */
     /** Blocking send of content.
      * @param content The content to send.
      * @throws IOException
      */
     public void sendContent(ByteBuffer content) throws IOException
     {
         try(Blocker blocker=_writeblock.acquire())
         {
             write(content,true,blocker);
             blocker.block();
         }
     }
 
     /* ------------------------------------------------------------ */
     /** Blocking send of content.
      * @param in The content to send
      * @throws IOException
      */
     public void sendContent(InputStream in) throws IOException
     {
         try(Blocker blocker=_writeblock.acquire())
         {
             new InputStreamWritingCB(in,blocker).iterate();
             blocker.block();
         }
     }
 
     /* ------------------------------------------------------------ */
     /** Blocking send of content.
      * @param in The content to send
      * @throws IOException
      */
     public void sendContent(ReadableByteChannel in) throws IOException
     {
         try(Blocker blocker=_writeblock.acquire())
         {
             new ReadableByteChannelWritingCB(in,blocker).iterate();
             blocker.block();
         }
     }
 
 
     /* ------------------------------------------------------------ */
     /** Blocking send of content.
      * @param content The content to send
      * @throws IOException
      */
     public void sendContent(HttpContent content) throws IOException
     {
         try(Blocker blocker=_writeblock.acquire())
         {
             sendContent(content,blocker);
             blocker.block();
         }
     }
 
     /* ------------------------------------------------------------ */
     /** Asynchronous send of content.
      * @param content The content to send
      * @param callback The callback to use to notify success or failure
      */
     public void sendContent(ByteBuffer content, final Callback callback)
     {
         write(content,true,new Callback()
         {
             @Override
             public void succeeded()
             {
                 closed();
                 callback.succeeded();
             }
 
             @Override
             public void failed(Throwable x)
             {
                 callback.failed(x);
             }
         });
     }
 
     /* ------------------------------------------------------------ */
     /** Asynchronous send of content.
      * @param in The content to send as a stream.  The stream will be closed
      * after reading all content.
      * @param callback The callback to use to notify success or failure
      */
     public void sendContent(InputStream in, Callback callback)
     {
         new InputStreamWritingCB(in,callback).iterate();
     }
 
     /* ------------------------------------------------------------ */
     /** Asynchronous send of content.
      * @param in The content to send as a channel.  The channel will be closed
      * after reading all content.
      * @param callback The callback to use to notify success or failure
      */
     public void sendContent(ReadableByteChannel in, Callback callback)
     {
         new ReadableByteChannelWritingCB(in,callback).iterate();
     }
 
     /* ------------------------------------------------------------ */
     /** Asynchronous send of content.
      * @param httpContent The content to send
      * @param callback The callback to use to notify success or failure
      */
     public void sendContent(HttpContent httpContent, Callback callback)
     {
         if (BufferUtil.hasContent(_aggregate))
         {
             callback.failed(new IOException("cannot sendContent() after write()"));
             return;
         }
         if (_channel.isCommitted())
         {
             callback.failed(new IOException("committed"));
             return;
         }
 
         while (true)
         {
             switch(_state.get())
             {
                 case OPEN:
                     if (!_state.compareAndSet(OutputState.OPEN, OutputState.PENDING))
                         continue;
                     break;
                 case ERROR:
                     callback.failed(new EofException(_onError));
                     return;
                     
                 case CLOSED:
                     callback.failed(new EofException("Closed"));
                     return;
                 default:
                     throw new IllegalStateException();
             }
             break;
         }
         ByteBuffer buffer= _channel.useDirectBuffers()?httpContent.getDirectBuffer():null;
         if (buffer == null)
             buffer = httpContent.getIndirectBuffer();
 
         if (buffer!=null)
         {
             if (LOG.isDebugEnabled())
                 LOG.debug("sendContent({}=={},{},direct={})",httpContent,BufferUtil.toDetailString(buffer),callback,_channel.useDirectBuffers());
             
             sendContent(buffer,callback);
             return;
         }
 
         try
         {
             ReadableByteChannel rbc=httpContent.getReadableByteChannel();
             if (rbc!=null)
             {
                 if (LOG.isDebugEnabled())
                     LOG.debug("sendContent({}=={},{},direct={})",httpContent,rbc,callback,_channel.useDirectBuffers());
                 // Close of the rbc is done by the async sendContent
                 sendContent(rbc,callback);
                 return;
             }
 
             InputStream in = httpContent.getInputStream();
             if ( in!=null )
             {
                 if (LOG.isDebugEnabled())
                     LOG.debug("sendContent({}=={},{},direct={})",httpContent,in,callback,_channel.useDirectBuffers());
                 sendContent(in,callback);
                 return;
             }
         }
         catch(Throwable th)
         {
             callback.failed(th);
             return;
         }
 
         callback.failed(new IllegalArgumentException("unknown content for "+httpContent));
     }
 
     public int getBufferSize()
     {
         return _bufferSize;
     }
 
     public void setBufferSize(int size)
     {
         _bufferSize = size;
         _commitSize = size;
     }
 
     public void resetBuffer()
     {
         if (BufferUtil.hasContent(_aggregate))
             BufferUtil.clear(_aggregate);
     }
 
     @Override
     public void setWriteListener(WriteListener writeListener)
     {
         if (!_channel.getState().isAsync())
             throw new IllegalStateException("!ASYNC");
 
         if (_state.compareAndSet(OutputState.OPEN, OutputState.READY))
         {
             _writeListener = writeListener;
             _channel.getState().onWritePossible();
         }
         else
             throw new IllegalStateException();
     }
 
     /**
      * @see javax.servlet.ServletOutputStream#isReady()
      */
     @Override
     public boolean isReady()
     {
         while (true)
         {
             switch(_state.get())
             {
                 case OPEN:
                     return true;
                 case ASYNC:
                     if (!_state.compareAndSet(OutputState.ASYNC, OutputState.READY))
                         continue;
                     return true;
                 case READY:
                     return true;
                 case PENDING:
                     if (!_state.compareAndSet(OutputState.PENDING, OutputState.UNREADY))
                         continue;
                     return false;
                 case UNREADY:
                     return false;
 
                 case ERROR:
                     return true;
                     
                 case CLOSED:
                     return true;
             }
         }
     }
 
     @Override
     public void run()
     {
         loop: while (true)
         {
             OutputState state = _state.get();
 
             if(_onError!=null)
             {
                 switch(state)
                 {
                     case CLOSED:
                     case ERROR:
                         _onError=null;
                         break loop;
 
                     default:
                         if (_state.compareAndSet(state, OutputState.ERROR))
                         {
                             Throwable th=_onError;
                             _onError=null;
                             if (LOG.isDebugEnabled())
                                 LOG.debug("onError",th);
                             _writeListener.onError(th);
                             close();
 
                             break loop;
                         }
 
                 }
                 continue;
             }
             
             switch(_state.get())
             {
                 case CLOSED:
                     // even though a write is not possible, because a close has 
                     // occurred, we need to call onWritePossible to tell async
                     // producer that the last write completed.
                     // so fall through
                 case READY:
                     try
                     {
                         _writeListener.onWritePossible();
                         break loop;
                     }
                     catch (Throwable e)
                     {
                         _onError=e;
                     }
                     break;
                     
                 default:
                     _onError=new IllegalStateException("state="+_state.get());
             }
         }
     }
     
     @Override
     public String toString()
     {
         return String.format("%s@%x{%s}",this.getClass().getSimpleName(),hashCode(),_state.get());
     }
     
     private abstract class AsyncICB extends IteratingCallback
     {
         @Override
         protected void onCompleteSuccess()
         {
             while(true)
             {
                 OutputState last=_state.get();
                 switch(last)
                 {
                     case PENDING:
                         if (!_state.compareAndSet(OutputState.PENDING, OutputState.ASYNC))
                             continue;
                         break;
 
                     case UNREADY:
                         if (!_state.compareAndSet(OutputState.UNREADY, OutputState.READY))
                             continue;
                         _channel.getState().onWritePossible();
                         break;
 
                     case CLOSED:
                         break;
 
                     default:
                         throw new IllegalStateException();
                 }
                 break;
             }
         }
 
         @Override
         public void onCompleteFailure(Throwable e)
         {
             _onError=e==null?new IOException():e;
             _channel.getState().onWritePossible();
         }
     }
     
     
     private class AsyncFlush extends AsyncICB
     {
         protected volatile boolean _flushed;
 
         public AsyncFlush()
         {
         }
 
         @Override
         protected Action process()
         {
             if (BufferUtil.hasContent(_aggregate))
             {
                 _flushed=true;
                 write(_aggregate, false, this);
                 return Action.SCHEDULED;
             }
 
             if (!_flushed)
             {
                 _flushed=true;
                 write(BufferUtil.EMPTY_BUFFER,false,this);
                 return Action.SCHEDULED;
             }
 
             return Action.SUCCEEDED;
         }
     }
 
 
 
     private class AsyncWrite extends AsyncICB
     {
         private final ByteBuffer _buffer;
         private final ByteBuffer _slice;
         private final boolean _complete;
         private final int _len;
         protected volatile boolean _completed;
 
         public AsyncWrite(byte[] b, int off, int len, boolean complete)
         {
             _buffer=ByteBuffer.wrap(b, off, len);
             _len=len;
             // always use a view for large byte arrays to avoid JVM pooling large direct buffers
             _slice=_len<getBufferSize()?null:_buffer.duplicate();
             _complete=complete;
         }
 
         public AsyncWrite(ByteBuffer buffer, boolean complete)
         {
             _buffer=buffer;
             _len=buffer.remaining();
             // Use a slice buffer for large indirect to avoid JVM pooling large direct buffers
             _slice=_buffer.isDirect()||_len<getBufferSize()?null:_buffer.duplicate();
             _complete=complete;
         }
 
         @Override
         protected Action process()
         {
             // flush any content from the aggregate
             if (BufferUtil.hasContent(_aggregate))
             {
                 _completed=_len==0;
                 write(_aggregate, _complete && _completed, this);
                 return Action.SCHEDULED;
             }
 
             // Can we just aggregate the remainder?
             if (!_complete && _len<BufferUtil.space(_aggregate) && _len<_commitSize)
             {
                 int position = BufferUtil.flipToFill(_aggregate);
                 BufferUtil.put(_buffer,_aggregate);
                 BufferUtil.flipToFlush(_aggregate, position);
                 return Action.SUCCEEDED;
             }
             
             // Is there data left to write?
             if (_buffer.hasRemaining())
             {
                 // if there is no slice, just write it
                 if (_slice==null)
                 {
                     _completed=true;
                     write(_buffer, _complete, this);
                     return Action.SCHEDULED;
                 }
                 
                 // otherwise take a slice
                 int p=_buffer.position();
                 int l=Math.min(getBufferSize(),_buffer.remaining());
                 int pl=p+l;
                 _slice.limit(pl);
                 _buffer.position(pl);
                 _slice.position(p);
                 _completed=!_buffer.hasRemaining();
                 write(_slice, _complete && _completed, this);
                 return Action.SCHEDULED;
             }
             
             // all content written, but if we have not yet signal completion, we
             // need to do so
             if (_complete && !_completed)
             {
                 _completed=true;
                 write(BufferUtil.EMPTY_BUFFER, _complete, this);
                 return Action.SCHEDULED;
             }
 
             return Action.SUCCEEDED;
         }
 
         @Override
         protected void onCompleteSuccess()
         {
             super.onCompleteSuccess();
             if (_complete)
                 closed();
         }
         
         
     }
 
 
     /* ------------------------------------------------------------ */
     /** An iterating callback that will take content from an
      * InputStream and write it to the associated {@link HttpChannel}.
      * A non direct buffer of size {@link HttpOutput#getBufferSize()} is used.
      * This callback is passed to the {@link HttpChannel#write(ByteBuffer, boolean, Callback)} to
      * be notified as each buffer is written and only once all the input is consumed will the
      * wrapped {@link Callback#succeeded()} method be called.
      */
     private class InputStreamWritingCB extends IteratingNestedCallback
     {
         private final InputStream _in;
         private final ByteBuffer _buffer;
         private boolean _eof;
 
         public InputStreamWritingCB(InputStream in, Callback callback)
         {
             super(callback);
             _in=in;
             _buffer = _channel.getByteBufferPool().acquire(getBufferSize(), false);
         }
 
         @Override
         protected Action process() throws Exception
         {
             // Only return if EOF has previously been read and thus
             // a write done with EOF=true
             if (_eof)
             {
                 // Handle EOF
                 _in.close();
                 closed();
                 _channel.getByteBufferPool().release(_buffer);
                 return Action.SUCCEEDED;
             }
             
             // Read until buffer full or EOF
             int len=0;
             while (len<_buffer.capacity() && !_eof)
             {
                 int r=_in.read(_buffer.array(),_buffer.arrayOffset()+len,_buffer.capacity()-len);
                 if (r<0)
                     _eof=true;
                 else
                     len+=r;
             }
 
             // write what we have
             _buffer.position(0);
             _buffer.limit(len);
             write(_buffer,_eof,this);
             return Action.SCHEDULED;
         }
 
         @Override
         public void onCompleteFailure(Throwable x)
         {
             super.onCompleteFailure(x);
             _channel.getByteBufferPool().release(_buffer);
             try
             {
                 _in.close();
             }
             catch (IOException e)
             {
                 LOG.ignore(e);
             }
         }
 
     }
 
     /* ------------------------------------------------------------ */
     /** An iterating callback that will take content from a
      * ReadableByteChannel and write it to the {@link HttpChannel}.
      * A {@link ByteBuffer} of size {@link HttpOutput#getBufferSize()} is used that will be direct if
      * {@link HttpChannel#useDirectBuffers()} is true.
      * This callback is passed to the {@link HttpChannel#write(ByteBuffer, boolean, Callback)} to
      * be notified as each buffer is written and only once all the input is consumed will the
      * wrapped {@link Callback#succeeded()} method be called.
      */
     private class ReadableByteChannelWritingCB extends IteratingNestedCallback
     {
         private final ReadableByteChannel _in;
         private final ByteBuffer _buffer;
         private boolean _eof;
 
         public ReadableByteChannelWritingCB(ReadableByteChannel in, Callback callback)
         {
             super(callback);
             _in=in;
             _buffer = _channel.getByteBufferPool().acquire(getBufferSize(), _channel.useDirectBuffers());
         }
 
         @Override
         protected Action process() throws Exception
         {
             // Only return if EOF has previously been read and thus
             // a write done with EOF=true
             if (_eof)
             {
                 _in.close();
                 closed();
                 _channel.getByteBufferPool().release(_buffer);
                 return Action.SUCCEEDED;
             }
             
             // Read from stream until buffer full or EOF
             _buffer.clear();
             while (_buffer.hasRemaining() && !_eof)
               _eof = (_in.read(_buffer)) <  0;
 
             // write what we have
             _buffer.flip();
             write(_buffer,_eof,this);
 
             return Action.SCHEDULED;
         }
 
         @Override
         public void onCompleteFailure(Throwable x)
         {
             super.onCompleteFailure(x);
             _channel.getByteBufferPool().release(_buffer);
             try
             {
                 _in.close();
             }
             catch (IOException e)
             {
                 LOG.ignore(e);
             }
         }
     }
 }