//
   //  ========================================================================
   //  Copyright (c) 1995-2016 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.http2;
  
  import org.eclipse.jetty.http2.frames.Frame;
  import org.eclipse.jetty.http2.frames.WindowUpdateFrame;
  import org.eclipse.jetty.util.Callback;
  
  public class SimpleFlowControlStrategy extends AbstractFlowControlStrategy
  {
      public SimpleFlowControlStrategy()
      {
          this(DEFAULT_WINDOW_SIZE);
      }
  
      public SimpleFlowControlStrategy(int initialStreamSendWindow)
      {
          super(initialStreamSendWindow);
      }
  
      @Override
      public void onDataConsumed(ISession session, IStream stream, int length)
      {
          if (length <= 0)
              return;
  
          // This is the simple algorithm for flow control.
          // This method is called when a whole flow controlled frame has been consumed.
          // We send a WindowUpdate every time, even if the frame was very small.
  
          WindowUpdateFrame sessionFrame = new WindowUpdateFrame(0, length);
          session.updateRecvWindow(length);
          if (LOG.isDebugEnabled())
              LOG.debug("Data consumed, increased session recv window by {} for {}", length, session);
  
          Frame[] streamFrame = Frame.EMPTY_ARRAY;
          if (stream != null)
          {
              if (stream.isClosed())
              {
                  if (LOG.isDebugEnabled())
                      LOG.debug("Data consumed, ignoring update stream recv window by {} for closed {}", length, stream);
              }
              else
              {
                  streamFrame = new Frame[1];
                  streamFrame[0] = new WindowUpdateFrame(stream.getId(), length);
                  stream.updateRecvWindow(length);
                  if (LOG.isDebugEnabled())
                      LOG.debug("Data consumed, increased stream recv window by {} for {}", length, stream);
              }
          }
  
          session.frames(stream, Callback.NOOP, sessionFrame, streamFrame);
      }
  }