/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
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 *  See the License for the specific language governing permissions and
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package org.apache.coyote.http2;

import java.util.Collections;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.res.StringManager;

Base class for all streams including the connection (referred to as Stream 0) and is used primarily when managing prioritization.
/** * Base class for all streams including the connection (referred to as Stream 0) * and is used primarily when managing prioritization. */
abstract class AbstractStream { private static final Log log = LogFactory.getLog(AbstractStream.class); private static final StringManager sm = StringManager.getManager(AbstractStream.class); private final Integer identifier; private final String idAsString; private volatile AbstractStream parentStream = null; private final Set<AbstractNonZeroStream> childStreams = Collections.newSetFromMap(new ConcurrentHashMap<>()); private long windowSize = ConnectionSettingsBase.DEFAULT_INITIAL_WINDOW_SIZE; AbstractStream(Integer identifier) { this.identifier = identifier; this.idAsString = identifier.toString(); } final Integer getIdentifier() { return identifier; } final String getIdAsString() { return idAsString; } final int getIdAsInt() { return identifier.intValue(); } final void detachFromParent() { if (parentStream != null) { parentStream.getChildStreams().remove(this); parentStream = null; } } final void addChild(AbstractNonZeroStream child) { child.setParentStream(this); childStreams.add(child); } final boolean isDescendant(AbstractStream stream) { // Is the passed in Stream a descendant of this Stream? // Start at the passed in Stream and work up AbstractStream parent = stream.getParentStream(); while (parent != null && parent != this) { parent = parent.getParentStream(); } return parent != null; } final AbstractStream getParentStream() { return parentStream; } final void setParentStream(AbstractStream parentStream) { this.parentStream = parentStream; } final Set<AbstractNonZeroStream> getChildStreams() { return childStreams; } final synchronized void setWindowSize(long windowSize) { this.windowSize = windowSize; } final synchronized long getWindowSize() { return windowSize; }
Increment window size.
Params:
  • increment – The amount by which the window size should be increased
Throws:
  • Http2Exception – If the window size is now higher than the maximum allowed
/** * Increment window size. * @param increment The amount by which the window size should be increased * @throws Http2Exception If the window size is now higher than * the maximum allowed */
synchronized void incrementWindowSize(int increment) throws Http2Exception { // No need for overflow protection here. // Increment can't be more than Integer.MAX_VALUE and once windowSize // goes beyond 2^31-1 an error is triggered. windowSize += increment; if (log.isDebugEnabled()) { log.debug(sm.getString("abstractStream.windowSizeInc", getConnectionId(), getIdAsString(), Integer.toString(increment), Long.toString(windowSize))); } if (windowSize > ConnectionSettingsBase.MAX_WINDOW_SIZE) { String msg = sm.getString("abstractStream.windowSizeTooBig", getConnectionId(), identifier, Integer.toString(increment), Long.toString(windowSize)); if (identifier.intValue() == 0) { throw new ConnectionException(msg, Http2Error.FLOW_CONTROL_ERROR); } else { throw new StreamException( msg, Http2Error.FLOW_CONTROL_ERROR, identifier.intValue()); } } } final synchronized void decrementWindowSize(int decrement) { // No need for overflow protection here. Decrement can never be larger // the Integer.MAX_VALUE and once windowSize goes negative no further // decrements are permitted windowSize -= decrement; if (log.isDebugEnabled()) { log.debug(sm.getString("abstractStream.windowSizeDec", getConnectionId(), getIdAsString(), Integer.toString(decrement), Long.toString(windowSize))); } } abstract String getConnectionId(); abstract int getWeight(); }