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//
// ========================================================================
// 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.spdy;
import java.util.concurrent.TimeUnit;
import org.eclipse.jetty.spdy.api.DataInfo;
import org.eclipse.jetty.spdy.api.Stream;
import org.eclipse.jetty.spdy.frames.WindowUpdateFrame;
import org.eclipse.jetty.util.Callback;
public class SPDYv3FlowControlStrategy implements FlowControlStrategy
{
private volatile int windowSize;
@Override
public int getWindowSize(ISession session)
{
return windowSize;
}
@Override
public void setWindowSize(ISession session, int windowSize)
{
int prevWindowSize = this.windowSize;
this.windowSize = windowSize;
for (Stream stream : session.getStreams())
((IStream)stream).updateWindowSize(windowSize - prevWindowSize);
}
@Override
public void onNewStream(ISession session, IStream stream)
{
stream.updateWindowSize(windowSize);
}
@Override
public void onWindowUpdate(ISession session, IStream stream, int delta)
{
if (stream != null)
stream.updateWindowSize(delta);
}
@Override
public void updateWindow(ISession session, IStream stream, int delta)
{
stream.updateWindowSize(delta);
}
@Override
public void onDataReceived(ISession session, IStream stream, DataInfo dataInfo)
{
// Do nothing
}
@Override
public void onDataConsumed(ISession session, IStream stream, DataInfo dataInfo, int delta)
{
// This is the algorithm for flow control.
// This method may be called multiple times with delta=1, but we only send a window
// update when the whole dataInfo has been consumed.
// Other policies may be to send window updates when consumed() is greater than
// a certain threshold, etc. but for now the policy is not pluggable for simplicity.
// Note that the frequency of window updates depends on the read buffer, that
// should not be too smaller than the window size to avoid frequent window updates.
// Therefore, a pluggable policy should be able to modify the read buffer capacity.
int length = dataInfo.length();
if (dataInfo.consumed() == length && !stream.isClosed() && length > 0)
{
WindowUpdateFrame windowUpdateFrame = new WindowUpdateFrame(session.getVersion(), stream.getId(), length);
session.control(stream, windowUpdateFrame, 0, TimeUnit.MILLISECONDS, Callback.Adapter.INSTANCE);
}
}
}
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