io.netty.handler.codec.http2.WeightedFairQueueByteDistributor Maven / Gradle / Ivy
/*
* Copyright 2015 The Netty Project
*
* The Netty Project 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:
*
* https://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, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package io.netty.handler.codec.http2;
import io.netty.util.collection.IntCollections;
import io.netty.util.collection.IntObjectHashMap;
import io.netty.util.collection.IntObjectMap;
import io.netty.util.internal.DefaultPriorityQueue;
import io.netty.util.internal.EmptyPriorityQueue;
import io.netty.util.internal.MathUtil;
import io.netty.util.internal.PriorityQueue;
import io.netty.util.internal.PriorityQueueNode;
import io.netty.util.internal.SystemPropertyUtil;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import static io.netty.handler.codec.http2.Http2CodecUtil.CONNECTION_STREAM_ID;
import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_MIN_ALLOCATION_CHUNK;
import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_PRIORITY_WEIGHT;
import static io.netty.handler.codec.http2.Http2CodecUtil.streamableBytes;
import static io.netty.handler.codec.http2.Http2Error.INTERNAL_ERROR;
import static io.netty.handler.codec.http2.Http2Exception.connectionError;
import static io.netty.util.internal.ObjectUtil.checkPositive;
import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
import static java.lang.Integer.MAX_VALUE;
import static java.lang.Math.max;
import static java.lang.Math.min;
/**
* A {@link StreamByteDistributor} that is sensitive to stream priority and uses
* Weighted Fair Queueing approach for distributing
* bytes.
*
* Inspiration for this distributor was taken from Linux's
* Completely Fair Scheduler
* to model the distribution of bytes to simulate an "ideal multi-tasking CPU", but in this case we are simulating
* an "ideal multi-tasking NIC".
*
* Each write operation will use the {@link #allocationQuantum(int)} to know how many more bytes should be allocated
* relative to the next stream which wants to write. This is to balance fairness while also considering goodput.
*/
public final class WeightedFairQueueByteDistributor implements StreamByteDistributor {
/**
* The initial size of the children map is chosen to be conservative on initial memory allocations under
* the assumption that most streams will have a small number of children. This choice may be
* sub-optimal if when children are present there are many children (i.e. a web page which has many
* dependencies to load).
*
* Visible only for testing!
*/
static final int INITIAL_CHILDREN_MAP_SIZE =
max(1, SystemPropertyUtil.getInt("io.netty.http2.childrenMapSize", 2));
/**
* FireFox currently uses 5 streams to establish QoS classes.
*/
private static final int DEFAULT_MAX_STATE_ONLY_SIZE = 5;
private final Http2Connection.PropertyKey stateKey;
/**
* If there is no Http2Stream object, but we still persist priority information then this is where the state will
* reside.
*/
private final IntObjectMap stateOnlyMap;
/**
* This queue will hold streams that are not active and provides the capability to retain priority for streams which
* have no {@link Http2Stream} object. See {@link StateOnlyComparator} for the priority comparator.
*/
private final PriorityQueue stateOnlyRemovalQueue;
private final Http2Connection connection;
private final State connectionState;
/**
* The minimum number of bytes that we will attempt to allocate to a stream. This is to
* help improve goodput on a per-stream basis.
*/
private int allocationQuantum = DEFAULT_MIN_ALLOCATION_CHUNK;
private final int maxStateOnlySize;
public WeightedFairQueueByteDistributor(Http2Connection connection) {
this(connection, DEFAULT_MAX_STATE_ONLY_SIZE);
}
public WeightedFairQueueByteDistributor(Http2Connection connection, int maxStateOnlySize) {
checkPositiveOrZero(maxStateOnlySize, "maxStateOnlySize");
if (maxStateOnlySize == 0) {
stateOnlyMap = IntCollections.emptyMap();
stateOnlyRemovalQueue = EmptyPriorityQueue.instance();
} else {
stateOnlyMap = new IntObjectHashMap(maxStateOnlySize);
// +2 because we may exceed the limit by 2 if a new dependency has no associated Http2Stream object. We need
// to create the State objects to put them into the dependency tree, which then impacts priority.
stateOnlyRemovalQueue = new DefaultPriorityQueue(StateOnlyComparator.INSTANCE, maxStateOnlySize + 2);
}
this.maxStateOnlySize = maxStateOnlySize;
this.connection = connection;
stateKey = connection.newKey();
final Http2Stream connectionStream = connection.connectionStream();
connectionStream.setProperty(stateKey, connectionState = new State(connectionStream, 16));
// Register for notification of new streams.
connection.addListener(new Http2ConnectionAdapter() {
@Override
public void onStreamAdded(Http2Stream stream) {
State state = stateOnlyMap.remove(stream.id());
if (state == null) {
state = new State(stream);
// Only the stream which was just added will change parents. So we only need an array of size 1.
List events = new ArrayList(1);
connectionState.takeChild(state, false, events);
notifyParentChanged(events);
} else {
stateOnlyRemovalQueue.removeTyped(state);
state.stream = stream;
}
switch (stream.state()) {
case RESERVED_REMOTE:
case RESERVED_LOCAL:
state.setStreamReservedOrActivated();
// wasStreamReservedOrActivated is part of the comparator for stateOnlyRemovalQueue there is no
// need to reprioritize here because it will not be in stateOnlyRemovalQueue.
break;
default:
break;
}
stream.setProperty(stateKey, state);
}
@Override
public void onStreamActive(Http2Stream stream) {
state(stream).setStreamReservedOrActivated();
// wasStreamReservedOrActivated is part of the comparator for stateOnlyRemovalQueue there is no need to
// reprioritize here because it will not be in stateOnlyRemovalQueue.
}
@Override
public void onStreamClosed(Http2Stream stream) {
state(stream).close();
}
@Override
public void onStreamRemoved(Http2Stream stream) {
// The stream has been removed from the connection. We can no longer rely on the stream's property
// storage to track the State. If we have room, and the precedence of the stream is sufficient, we
// should retain the State in the stateOnlyMap.
State state = state(stream);
// Typically the stream is set to null when the stream is closed because it is no longer needed to write
// data. However if the stream was not activated it may not be closed (reserved streams) so we ensure
// the stream reference is set to null to avoid retaining a reference longer than necessary.
state.stream = null;
if (WeightedFairQueueByteDistributor.this.maxStateOnlySize == 0) {
state.parent.removeChild(state);
return;
}
if (stateOnlyRemovalQueue.size() == WeightedFairQueueByteDistributor.this.maxStateOnlySize) {
State stateToRemove = stateOnlyRemovalQueue.peek();
if (StateOnlyComparator.INSTANCE.compare(stateToRemove, state) >= 0) {
// The "lowest priority" stream is a "higher priority" than the stream being removed, so we
// just discard the state.
state.parent.removeChild(state);
return;
}
stateOnlyRemovalQueue.poll();
stateToRemove.parent.removeChild(stateToRemove);
stateOnlyMap.remove(stateToRemove.streamId);
}
stateOnlyRemovalQueue.add(state);
stateOnlyMap.put(state.streamId, state);
}
});
}
@Override
public void updateStreamableBytes(StreamState state) {
state(state.stream()).updateStreamableBytes(streamableBytes(state),
state.hasFrame() && state.windowSize() >= 0);
}
@Override
public void updateDependencyTree(int childStreamId, int parentStreamId, short weight, boolean exclusive) {
State state = state(childStreamId);
if (state == null) {
// If there is no State object that means there is no Http2Stream object and we would have to keep the
// State object in the stateOnlyMap and stateOnlyRemovalQueue. However if maxStateOnlySize is 0 this means
// stateOnlyMap and stateOnlyRemovalQueue are empty collections and cannot be modified so we drop the State.
if (maxStateOnlySize == 0) {
return;
}
state = new State(childStreamId);
stateOnlyRemovalQueue.add(state);
stateOnlyMap.put(childStreamId, state);
}
State newParent = state(parentStreamId);
if (newParent == null) {
// If there is no State object that means there is no Http2Stream object and we would have to keep the
// State object in the stateOnlyMap and stateOnlyRemovalQueue. However if maxStateOnlySize is 0 this means
// stateOnlyMap and stateOnlyRemovalQueue are empty collections and cannot be modified so we drop the State.
if (maxStateOnlySize == 0) {
return;
}
newParent = new State(parentStreamId);
stateOnlyRemovalQueue.add(newParent);
stateOnlyMap.put(parentStreamId, newParent);
// Only the stream which was just added will change parents. So we only need an array of size 1.
List events = new ArrayList(1);
connectionState.takeChild(newParent, false, events);
notifyParentChanged(events);
}
// if activeCountForTree == 0 then it will not be in its parent's pseudoTimeQueue and thus should not be counted
// toward parent.totalQueuedWeights.
if (state.activeCountForTree != 0 && state.parent != null) {
state.parent.totalQueuedWeights += weight - state.weight;
}
state.weight = weight;
if (newParent != state.parent || exclusive && newParent.children.size() != 1) {
final List events;
if (newParent.isDescendantOf(state)) {
events = new ArrayList(2 + (exclusive ? newParent.children.size() : 0));
state.parent.takeChild(newParent, false, events);
} else {
events = new ArrayList(1 + (exclusive ? newParent.children.size() : 0));
}
newParent.takeChild(state, exclusive, events);
notifyParentChanged(events);
}
// The location in the dependency tree impacts the priority in the stateOnlyRemovalQueue map. If we created new
// State objects we must check if we exceeded the limit after we insert into the dependency tree to ensure the
// stateOnlyRemovalQueue has been updated.
while (stateOnlyRemovalQueue.size() > maxStateOnlySize) {
State stateToRemove = stateOnlyRemovalQueue.poll();
stateToRemove.parent.removeChild(stateToRemove);
stateOnlyMap.remove(stateToRemove.streamId);
}
}
@Override
public boolean distribute(int maxBytes, Writer writer) throws Http2Exception {
// As long as there is some active frame we should write at least 1 time.
if (connectionState.activeCountForTree == 0) {
return false;
}
// The goal is to write until we write all the allocated bytes or are no longer making progress.
// We still attempt to write even after the number of allocated bytes has been exhausted to allow empty frames
// to be sent. Making progress means the active streams rooted at the connection stream has changed.
int oldIsActiveCountForTree;
do {
oldIsActiveCountForTree = connectionState.activeCountForTree;
// connectionState will never be active, so go right to its children.
maxBytes -= distributeToChildren(maxBytes, writer, connectionState);
} while (connectionState.activeCountForTree != 0 &&
(maxBytes > 0 || oldIsActiveCountForTree != connectionState.activeCountForTree));
return connectionState.activeCountForTree != 0;
}
/**
* Sets the amount of bytes that will be allocated to each stream. Defaults to 1KiB.
* @param allocationQuantum the amount of bytes that will be allocated to each stream. Must be > 0.
*/
public void allocationQuantum(int allocationQuantum) {
checkPositive(allocationQuantum, "allocationQuantum");
this.allocationQuantum = allocationQuantum;
}
private int distribute(int maxBytes, Writer writer, State state) throws Http2Exception {
if (state.isActive()) {
int nsent = min(maxBytes, state.streamableBytes);
state.write(nsent, writer);
if (nsent == 0 && maxBytes != 0) {
// If a stream sends zero bytes, then we gave it a chance to write empty frames and it is now
// considered inactive until the next call to updateStreamableBytes. This allows descendant streams to
// be allocated bytes when the parent stream can't utilize them. This may be as a result of the
// stream's flow control window being 0.
state.updateStreamableBytes(state.streamableBytes, false);
}
return nsent;
}
return distributeToChildren(maxBytes, writer, state);
}
/**
* It is a pre-condition that {@code state.poll()} returns a non-{@code null} value. This is a result of the way
* the allocation algorithm is structured and can be explained in the following cases:
* For the recursive case
* If a stream has no children (in the allocation tree) than that node must be active or it will not be in the
* allocation tree. If a node is active then it will not delegate to children and recursion ends.
* For the initial case
* We check connectionState.activeCountForTree == 0 before any allocation is done. So if the connection stream
* has no active children we don't get into this method.
*/
private int distributeToChildren(int maxBytes, Writer writer, State state) throws Http2Exception {
long oldTotalQueuedWeights = state.totalQueuedWeights;
State childState = state.pollPseudoTimeQueue();
State nextChildState = state.peekPseudoTimeQueue();
childState.setDistributing();
try {
assert nextChildState == null || nextChildState.pseudoTimeToWrite >= childState.pseudoTimeToWrite :
"nextChildState[" + nextChildState.streamId + "].pseudoTime(" + nextChildState.pseudoTimeToWrite +
") < " + " childState[" + childState.streamId + "].pseudoTime(" + childState.pseudoTimeToWrite + ')';
int nsent = distribute(nextChildState == null ? maxBytes :
min(maxBytes, (int) min((nextChildState.pseudoTimeToWrite - childState.pseudoTimeToWrite) *
childState.weight / oldTotalQueuedWeights + allocationQuantum, MAX_VALUE)
),
writer,
childState);
state.pseudoTime += nsent;
childState.updatePseudoTime(state, nsent, oldTotalQueuedWeights);
return nsent;
} finally {
childState.unsetDistributing();
// Do in finally to ensure the internal flags is not corrupted if an exception is thrown.
// The offer operation is delayed until we unroll up the recursive stack, so we don't have to remove from
// the priority pseudoTimeQueue due to a write operation.
if (childState.activeCountForTree != 0) {
state.offerPseudoTimeQueue(childState);
}
}
}
private State state(Http2Stream stream) {
return stream.getProperty(stateKey);
}
private State state(int streamId) {
Http2Stream stream = connection.stream(streamId);
return stream != null ? state(stream) : stateOnlyMap.get(streamId);
}
/**
* For testing only!
*/
boolean isChild(int childId, int parentId, short weight) {
State parent = state(parentId);
State child;
return parent.children.containsKey(childId) &&
(child = state(childId)).parent == parent && child.weight == weight;
}
/**
* For testing only!
*/
int numChildren(int streamId) {
State state = state(streamId);
return state == null ? 0 : state.children.size();
}
/**
* Notify all listeners of the priority tree change events (in ascending order)
* @param events The events (top down order) which have changed
*/
void notifyParentChanged(List events) {
for (int i = 0; i < events.size(); ++i) {
ParentChangedEvent event = events.get(i);
stateOnlyRemovalQueue.priorityChanged(event.state);
if (event.state.parent != null && event.state.activeCountForTree != 0) {
event.state.parent.offerAndInitializePseudoTime(event.state);
event.state.parent.activeCountChangeForTree(event.state.activeCountForTree);
}
}
}
/**
* A comparator for {@link State} which has no associated {@link Http2Stream} object. The general precedence is:
*
* - Was a stream activated or reserved (streams only used for priority are higher priority)
* - Depth in the priority tree (closer to root is higher priority>
* - Stream ID (higher stream ID is higher priority - used for tie breaker)
*
*/
private static final class StateOnlyComparator implements Comparator, Serializable {
private static final long serialVersionUID = -4806936913002105966L;
static final StateOnlyComparator INSTANCE = new StateOnlyComparator();
@Override
public int compare(State o1, State o2) {
// "priority only streams" (which have not been activated) are higher priority than streams used for data.
boolean o1Actived = o1.wasStreamReservedOrActivated();
if (o1Actived != o2.wasStreamReservedOrActivated()) {
return o1Actived ? -1 : 1;
}
// Numerically greater depth is higher priority.
int x = o2.dependencyTreeDepth - o1.dependencyTreeDepth;
// I also considered tracking the number of streams which are "activated" (eligible transfer data) at each
// subtree. This would require a traversal from each node to the root on dependency tree structural changes,
// and then it would require a re-prioritization at each of these nodes (instead of just the nodes where the
// direct parent changed). The costs of this are judged to be relatively high compared to the nominal
// benefit it provides to the heuristic. Instead folks should just increase maxStateOnlySize.
// Last resort is to give larger stream ids more priority.
return x != 0 ? x : o1.streamId - o2.streamId;
}
}
private static final class StatePseudoTimeComparator implements Comparator, Serializable {
private static final long serialVersionUID = -1437548640227161828L;
static final StatePseudoTimeComparator INSTANCE = new StatePseudoTimeComparator();
@Override
public int compare(State o1, State o2) {
return MathUtil.compare(o1.pseudoTimeToWrite, o2.pseudoTimeToWrite);
}
}
/**
* The remote flow control state for a single stream.
*/
private final class State implements PriorityQueueNode {
private static final byte STATE_IS_ACTIVE = 0x1;
private static final byte STATE_IS_DISTRIBUTING = 0x2;
private static final byte STATE_STREAM_ACTIVATED = 0x4;
/**
* Maybe {@code null} if the stream if the stream is not active.
*/
Http2Stream stream;
State parent;
IntObjectMap children = IntCollections.emptyMap();
private final PriorityQueue pseudoTimeQueue;
final int streamId;
int streamableBytes;
int dependencyTreeDepth;
/**
* Count of nodes rooted at this sub tree with {@link #isActive()} equal to {@code true}.
*/
int activeCountForTree;
private int pseudoTimeQueueIndex = INDEX_NOT_IN_QUEUE;
private int stateOnlyQueueIndex = INDEX_NOT_IN_QUEUE;
/**
* An estimate of when this node should be given the opportunity to write data.
*/
long pseudoTimeToWrite;
/**
* A pseudo time maintained for immediate children to base their {@link #pseudoTimeToWrite} off of.
*/
long pseudoTime;
long totalQueuedWeights;
private byte flags;
short weight = DEFAULT_PRIORITY_WEIGHT;
State(int streamId) {
this(streamId, null, 0);
}
State(Http2Stream stream) {
this(stream, 0);
}
State(Http2Stream stream, int initialSize) {
this(stream.id(), stream, initialSize);
}
State(int streamId, Http2Stream stream, int initialSize) {
this.stream = stream;
this.streamId = streamId;
pseudoTimeQueue = new DefaultPriorityQueue(StatePseudoTimeComparator.INSTANCE, initialSize);
}
boolean isDescendantOf(State state) {
State next = parent;
while (next != null) {
if (next == state) {
return true;
}
next = next.parent;
}
return false;
}
void takeChild(State child, boolean exclusive, List events) {
takeChild(null, child, exclusive, events);
}
/**
* Adds a child to this priority. If exclusive is set, any children of this node are moved to being dependent on
* the child.
*/
void takeChild(Iterator> childItr, State child, boolean exclusive,
List events) {
State oldParent = child.parent;
if (oldParent != this) {
events.add(new ParentChangedEvent(child, oldParent));
child.setParent(this);
// If the childItr is not null we are iterating over the oldParent.children collection and should
// use the iterator to remove from the collection to avoid concurrent modification. Otherwise it is
// assumed we are not iterating over this collection and it is safe to call remove directly.
if (childItr != null) {
childItr.remove();
} else if (oldParent != null) {
oldParent.children.remove(child.streamId);
}
// Lazily initialize the children to save object allocations.
initChildrenIfEmpty();
final State oldChild = children.put(child.streamId, child);
assert oldChild == null : "A stream with the same stream ID was already in the child map.";
}
if (exclusive && !children.isEmpty()) {
// If it was requested that this child be the exclusive dependency of this node,
// move any previous children to the child node, becoming grand children of this node.
Iterator> itr = removeAllChildrenExcept(child).entries().iterator();
while (itr.hasNext()) {
child.takeChild(itr, itr.next().value(), false, events);
}
}
}
/**
* Removes the child priority and moves any of its dependencies to being direct dependencies on this node.
*/
void removeChild(State child) {
if (children.remove(child.streamId) != null) {
List events = new ArrayList(1 + child.children.size());
events.add(new ParentChangedEvent(child, child.parent));
child.setParent(null);
if (!child.children.isEmpty()) {
// Move up any grand children to be directly dependent on this node.
Iterator> itr = child.children.entries().iterator();
long totalWeight = child.getTotalWeight();
do {
// Redistribute the weight of child to its dependency proportionally.
State dependency = itr.next().value();
dependency.weight = (short) max(1, dependency.weight * child.weight / totalWeight);
takeChild(itr, dependency, false, events);
} while (itr.hasNext());
}
notifyParentChanged(events);
}
}
private long getTotalWeight() {
long totalWeight = 0L;
for (State state : children.values()) {
totalWeight += state.weight;
}
return totalWeight;
}
/**
* Remove all children with the exception of {@code streamToRetain}.
* This method is intended to be used to support an exclusive priority dependency operation.
* @return The map of children prior to this operation, excluding {@code streamToRetain} if present.
*/
private IntObjectMap removeAllChildrenExcept(State stateToRetain) {
stateToRetain = children.remove(stateToRetain.streamId);
IntObjectMap prevChildren = children;
// This map should be re-initialized in anticipation for the 1 exclusive child which will be added.
// It will either be added directly in this method, or after this method is called...but it will be added.
initChildren();
if (stateToRetain != null) {
children.put(stateToRetain.streamId, stateToRetain);
}
return prevChildren;
}
private void setParent(State newParent) {
// if activeCountForTree == 0 then it will not be in its parent's pseudoTimeQueue.
if (activeCountForTree != 0 && parent != null) {
parent.removePseudoTimeQueue(this);
parent.activeCountChangeForTree(-activeCountForTree);
}
parent = newParent;
// Use MAX_VALUE if no parent because lower depth is considered higher priority by StateOnlyComparator.
dependencyTreeDepth = newParent == null ? MAX_VALUE : newParent.dependencyTreeDepth + 1;
}
private void initChildrenIfEmpty() {
if (children == IntCollections.emptyMap()) {
initChildren();
}
}
private void initChildren() {
children = new IntObjectHashMap(INITIAL_CHILDREN_MAP_SIZE);
}
void write(int numBytes, Writer writer) throws Http2Exception {
assert stream != null;
try {
writer.write(stream, numBytes);
} catch (Throwable t) {
throw connectionError(INTERNAL_ERROR, t, "byte distribution write error");
}
}
void activeCountChangeForTree(int increment) {
assert activeCountForTree + increment >= 0;
activeCountForTree += increment;
if (parent != null) {
assert activeCountForTree != increment ||
pseudoTimeQueueIndex == INDEX_NOT_IN_QUEUE ||
parent.pseudoTimeQueue.containsTyped(this) :
"State[" + streamId + "].activeCountForTree changed from 0 to " + increment + " is in a " +
"pseudoTimeQueue, but not in parent[ " + parent.streamId + "]'s pseudoTimeQueue";
if (activeCountForTree == 0) {
parent.removePseudoTimeQueue(this);
} else if (activeCountForTree == increment && !isDistributing()) {
// If frame count was 0 but is now not, and this node is not already in a pseudoTimeQueue (assumed
// to be pState's pseudoTimeQueue) then enqueue it. If this State object is being processed the
// pseudoTime for this node should not be adjusted, and the node will be added back to the
// pseudoTimeQueue/tree structure after it is done being processed. This may happen if the
// activeCountForTree == 0 (a node which can't stream anything and is blocked) is at/near root of
// the tree, and is popped off the pseudoTimeQueue during processing, and then put back on the
// pseudoTimeQueue because a child changes position in the priority tree (or is closed because it is
// not blocked and finished writing all data).
parent.offerAndInitializePseudoTime(this);
}
parent.activeCountChangeForTree(increment);
}
}
void updateStreamableBytes(int newStreamableBytes, boolean isActive) {
if (isActive() != isActive) {
if (isActive) {
activeCountChangeForTree(1);
setActive();
} else {
activeCountChangeForTree(-1);
unsetActive();
}
}
streamableBytes = newStreamableBytes;
}
/**
* Assumes the parents {@link #totalQueuedWeights} includes this node's weight.
*/
void updatePseudoTime(State parentState, int nsent, long totalQueuedWeights) {
assert streamId != CONNECTION_STREAM_ID && nsent >= 0;
// If the current pseudoTimeToSend is greater than parentState.pseudoTime then we previously over accounted
// and should use parentState.pseudoTime.
pseudoTimeToWrite = min(pseudoTimeToWrite, parentState.pseudoTime) + nsent * totalQueuedWeights / weight;
}
/**
* The concept of pseudoTime can be influenced by priority tree manipulations or if a stream goes from "active"
* to "non-active". This method accounts for that by initializing the {@link #pseudoTimeToWrite} for
* {@code state} to {@link #pseudoTime} of this node and then calls {@link #offerPseudoTimeQueue(State)}.
*/
void offerAndInitializePseudoTime(State state) {
state.pseudoTimeToWrite = pseudoTime;
offerPseudoTimeQueue(state);
}
void offerPseudoTimeQueue(State state) {
pseudoTimeQueue.offer(state);
totalQueuedWeights += state.weight;
}
/**
* Must only be called if the pseudoTimeQueue is non-empty!
*/
State pollPseudoTimeQueue() {
State state = pseudoTimeQueue.poll();
// This method is only ever called if the pseudoTimeQueue is non-empty.
totalQueuedWeights -= state.weight;
return state;
}
void removePseudoTimeQueue(State state) {
if (pseudoTimeQueue.removeTyped(state)) {
totalQueuedWeights -= state.weight;
}
}
State peekPseudoTimeQueue() {
return pseudoTimeQueue.peek();
}
void close() {
updateStreamableBytes(0, false);
stream = null;
}
boolean wasStreamReservedOrActivated() {
return (flags & STATE_STREAM_ACTIVATED) != 0;
}
void setStreamReservedOrActivated() {
flags |= STATE_STREAM_ACTIVATED;
}
boolean isActive() {
return (flags & STATE_IS_ACTIVE) != 0;
}
private void setActive() {
flags |= STATE_IS_ACTIVE;
}
private void unsetActive() {
flags &= ~STATE_IS_ACTIVE;
}
boolean isDistributing() {
return (flags & STATE_IS_DISTRIBUTING) != 0;
}
void setDistributing() {
flags |= STATE_IS_DISTRIBUTING;
}
void unsetDistributing() {
flags &= ~STATE_IS_DISTRIBUTING;
}
@Override
public int priorityQueueIndex(DefaultPriorityQueue queue) {
return queue == stateOnlyRemovalQueue ? stateOnlyQueueIndex : pseudoTimeQueueIndex;
}
@Override
public void priorityQueueIndex(DefaultPriorityQueue queue, int i) {
if (queue == stateOnlyRemovalQueue) {
stateOnlyQueueIndex = i;
} else {
pseudoTimeQueueIndex = i;
}
}
@Override
public String toString() {
// Use activeCountForTree as a rough estimate for how many nodes are in this subtree.
StringBuilder sb = new StringBuilder(256 * (activeCountForTree > 0 ? activeCountForTree : 1));
toString(sb);
return sb.toString();
}
private void toString(StringBuilder sb) {
sb.append("{streamId ").append(streamId)
.append(" streamableBytes ").append(streamableBytes)
.append(" activeCountForTree ").append(activeCountForTree)
.append(" pseudoTimeQueueIndex ").append(pseudoTimeQueueIndex)
.append(" pseudoTimeToWrite ").append(pseudoTimeToWrite)
.append(" pseudoTime ").append(pseudoTime)
.append(" flags ").append(flags)
.append(" pseudoTimeQueue.size() ").append(pseudoTimeQueue.size())
.append(" stateOnlyQueueIndex ").append(stateOnlyQueueIndex)
.append(" parent.streamId ").append(parent == null ? -1 : parent.streamId).append("} [");
if (!pseudoTimeQueue.isEmpty()) {
for (State s : pseudoTimeQueue) {
s.toString(sb);
sb.append(", ");
}
// Remove the last ", "
sb.setLength(sb.length() - 2);
}
sb.append(']');
}
}
/**
* Allows a correlation to be made between a stream and its old parent before a parent change occurs.
*/
private static final class ParentChangedEvent {
final State state;
final State oldParent;
/**
* Create a new instance.
* @param state The state who has had a parent change.
* @param oldParent The previous parent.
*/
ParentChangedEvent(State state, State oldParent) {
this.state = state;
this.oldParent = oldParent;
}
}
}