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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.http2;
import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import org.eclipse.jetty.http2.api.Stream;
import org.eclipse.jetty.http2.frames.WindowUpdateFrame;
import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.annotation.ManagedOperation;
import org.eclipse.jetty.util.component.ContainerLifeCycle;
import org.eclipse.jetty.util.component.Dumpable;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
@ManagedObject
public abstract class AbstractFlowControlStrategy implements FlowControlStrategy, Dumpable
{
protected static final Logger LOG = Log.getLogger(FlowControlStrategy.class);
private final AtomicLong sessionStall = new AtomicLong();
private final AtomicLong sessionStallTime = new AtomicLong();
private final Map<IStream, Long> streamsStalls = new ConcurrentHashMap<>();
private final AtomicLong streamsStallTime = new AtomicLong();
private int initialStreamSendWindow;
private int initialStreamRecvWindow;
public AbstractFlowControlStrategy(int initialStreamSendWindow)
{
this.initialStreamSendWindow = initialStreamSendWindow;
this.initialStreamRecvWindow = DEFAULT_WINDOW_SIZE;
}
@ManagedAttribute(value = "The initial size of stream's flow control send window", readonly = true)
public int getInitialStreamSendWindow()
{
return initialStreamSendWindow;
}
@ManagedAttribute(value = "The initial size of stream's flow control receive window", readonly = true)
public int getInitialStreamRecvWindow()
{
return initialStreamRecvWindow;
}
@Override
public void onStreamCreated(IStream stream)
{
stream.updateSendWindow(initialStreamSendWindow);
stream.updateRecvWindow(initialStreamRecvWindow);
}
@Override
public void onStreamDestroyed(IStream stream)
{
}
@Override
public void updateInitialStreamWindow(ISession session, int initialStreamWindow, boolean local)
{
int previousInitialStreamWindow;
if (local)
{
previousInitialStreamWindow = getInitialStreamRecvWindow();
this.initialStreamRecvWindow = initialStreamWindow;
}
else
{
previousInitialStreamWindow = getInitialStreamSendWindow();
this.initialStreamSendWindow = initialStreamWindow;
}
int delta = initialStreamWindow - previousInitialStreamWindow;
// SPEC: updates of the initial window size only affect stream windows, not session's.
for (Stream stream : session.getStreams())
{
if (local)
{
((IStream)stream).updateRecvWindow(delta);
if (LOG.isDebugEnabled())
LOG.debug("Updated initial stream recv window {} -> {} for {}", previousInitialStreamWindow, initialStreamWindow, stream);
}
else
{
session.onWindowUpdate((IStream)stream, new WindowUpdateFrame(stream.getId(), delta));
}
}
}
@Override
public void onWindowUpdate(ISession session, IStream stream, WindowUpdateFrame frame)
{
int delta = frame.getWindowDelta();
if (frame.getStreamId() > 0)
{
// The stream may have been removed concurrently.
if (stream != null)
{
int oldSize = stream.updateSendWindow(delta);
if (LOG.isDebugEnabled())
LOG.debug("Updated stream send window {} -> {} for {}", oldSize, oldSize + delta, stream);
if (oldSize <= 0)
onStreamUnstalled(stream);
}
}
else
{
int oldSize = session.updateSendWindow(delta);
if (LOG.isDebugEnabled())
LOG.debug("Updated session send window {} -> {} for {}", oldSize, oldSize + delta, session);
if (oldSize <= 0)
onSessionUnstalled(session);
}
}
@Override
public void onDataReceived(ISession session, IStream stream, int length)
{
int oldSize = session.updateRecvWindow(-length);
if (LOG.isDebugEnabled())
LOG.debug("Data received, updated session recv window {} -> {} for {}", oldSize, oldSize - length, session);
if (stream != null)
{
oldSize = stream.updateRecvWindow(-length);
if (LOG.isDebugEnabled())
LOG.debug("Data received, updated stream recv window {} -> {} for {}", oldSize, oldSize - length, stream);
}
}
@Override
public void windowUpdate(ISession session, IStream stream, WindowUpdateFrame frame)
{
}
@Override
public void onDataSending(IStream stream, int length)
{
if (length == 0)
return;
ISession session = stream.getSession();
int oldSessionWindow = session.updateSendWindow(-length);
int newSessionWindow = oldSessionWindow - length;
if (LOG.isDebugEnabled())
LOG.debug("Sending, session send window {} -> {} for {}", oldSessionWindow, newSessionWindow, session);
if (newSessionWindow <= 0)
onSessionStalled(session);
int oldStreamWindow = stream.updateSendWindow(-length);
int newStreamWindow = oldStreamWindow - length;
if (LOG.isDebugEnabled())
LOG.debug("Sending, stream send window {} -> {} for {}", oldStreamWindow, newStreamWindow, stream);
if (newStreamWindow <= 0)
onStreamStalled(stream);
}
@Override
public void onDataSent(IStream stream, int length)
{
}
protected void onSessionStalled(ISession session)
{
sessionStall.set(System.nanoTime());
if (LOG.isDebugEnabled())
LOG.debug("Session stalled {}", session);
}
protected void onStreamStalled(IStream stream)
{
streamsStalls.put(stream, System.nanoTime());
if (LOG.isDebugEnabled())
LOG.debug("Stream stalled {}", stream);
}
protected void onSessionUnstalled(ISession session)
{
sessionStallTime.addAndGet(System.nanoTime() - sessionStall.getAndSet(0));
if (LOG.isDebugEnabled())
LOG.debug("Session unstalled {}", session);
}
protected void onStreamUnstalled(IStream stream)
{
Long time = streamsStalls.remove(stream);
if (time != null)
streamsStallTime.addAndGet(System.nanoTime() - time);
if (LOG.isDebugEnabled())
LOG.debug("Stream unstalled {}", stream);
}
@ManagedAttribute(value = "The time, in milliseconds, that the session flow control has stalled", readonly = true)
public long getSessionStallTime()
{
return TimeUnit.NANOSECONDS.toMillis(sessionStallTime.get());
}
@ManagedAttribute(value = "The time, in milliseconds, that the streams flow control has stalled", readonly = true)
public long getStreamsStallTime()
{
return TimeUnit.NANOSECONDS.toMillis(streamsStallTime.get());
}
@ManagedOperation(value = "Resets the statistics", impact = "ACTION")
public void reset()
{
sessionStallTime.set(0);
streamsStallTime.set(0);
}
@Override
public String dump()
{
return ContainerLifeCycle.dump(this);
}
@Override
public void dump(Appendable out, String indent) throws IOException
{
out.append(toString()).append(System.lineSeparator());
}
}
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