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io.netty.channel.AbstractCoalescingBufferQueue Maven / Gradle / Ivy
/*
* Copyright 2017 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.channel;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.CompositeByteBuf;
import io.netty.util.internal.UnstableApi;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.util.ArrayDeque;
import static io.netty.util.ReferenceCountUtil.safeRelease;
import static io.netty.util.internal.ObjectUtil.checkNotNull;
import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
import static io.netty.util.internal.PlatformDependent.throwException;
@UnstableApi
public abstract class AbstractCoalescingBufferQueue {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(AbstractCoalescingBufferQueue.class);
private final ArrayDeque bufAndListenerPairs;
private final PendingBytesTracker tracker;
private int readableBytes;
/**
* Create a new instance.
*
* @param channel the {@link Channel} which will have the {@link Channel#isWritable()} reflect the amount of queued
* buffers or {@code null} if there is no writability state updated.
* @param initSize the initial size of the underlying queue.
*/
protected AbstractCoalescingBufferQueue(Channel channel, int initSize) {
bufAndListenerPairs = new ArrayDeque(initSize);
tracker = channel == null ? null : PendingBytesTracker.newTracker(channel);
}
/**
* Add a buffer to the front of the queue and associate a promise with it that should be completed when
* all the buffer's bytes have been consumed from the queue and written.
* @param buf to add to the head of the queue
* @param promise to complete when all the bytes have been consumed and written, can be void.
*/
public final void addFirst(ByteBuf buf, ChannelPromise promise) {
addFirst(buf, toChannelFutureListener(promise));
}
private void addFirst(ByteBuf buf, ChannelFutureListener listener) {
// Touch the message to make it easier to debug buffer leaks.
buf.touch();
if (listener != null) {
bufAndListenerPairs.addFirst(listener);
}
bufAndListenerPairs.addFirst(buf);
incrementReadableBytes(buf.readableBytes());
}
/**
* Add a buffer to the end of the queue.
*/
public final void add(ByteBuf buf) {
add(buf, (ChannelFutureListener) null);
}
/**
* Add a buffer to the end of the queue and associate a promise with it that should be completed when
* all the buffer's bytes have been consumed from the queue and written.
* @param buf to add to the tail of the queue
* @param promise to complete when all the bytes have been consumed and written, can be void.
*/
public final void add(ByteBuf buf, ChannelPromise promise) {
// buffers are added before promises so that we naturally 'consume' the entire buffer during removal
// before we complete it's promise.
add(buf, toChannelFutureListener(promise));
}
/**
* Add a buffer to the end of the queue and associate a listener with it that should be completed when
* all the buffers bytes have been consumed from the queue and written.
* @param buf to add to the tail of the queue
* @param listener to notify when all the bytes have been consumed and written, can be {@code null}.
*/
public final void add(ByteBuf buf, ChannelFutureListener listener) {
// Touch the message to make it easier to debug buffer leaks.
buf.touch();
// buffers are added before promises so that we naturally 'consume' the entire buffer during removal
// before we complete it's promise.
bufAndListenerPairs.add(buf);
if (listener != null) {
bufAndListenerPairs.add(listener);
}
incrementReadableBytes(buf.readableBytes());
}
/**
* Remove the first {@link ByteBuf} from the queue.
* @param aggregatePromise used to aggregate the promises and listeners for the returned buffer.
* @return the first {@link ByteBuf} from the queue.
*/
public final ByteBuf removeFirst(ChannelPromise aggregatePromise) {
Object entry = bufAndListenerPairs.poll();
if (entry == null) {
return null;
}
assert entry instanceof ByteBuf;
ByteBuf result = (ByteBuf) entry;
decrementReadableBytes(result.readableBytes());
entry = bufAndListenerPairs.peek();
if (entry instanceof ChannelFutureListener) {
aggregatePromise.addListener((ChannelFutureListener) entry);
bufAndListenerPairs.poll();
}
return result;
}
/**
* Remove a {@link ByteBuf} from the queue with the specified number of bytes. Any added buffer who's bytes are
* fully consumed during removal will have it's promise completed when the passed aggregate {@link ChannelPromise}
* completes.
*
* @param alloc The allocator used if a new {@link ByteBuf} is generated during the aggregation process.
* @param bytes the maximum number of readable bytes in the returned {@link ByteBuf}, if {@code bytes} is greater
* than {@link #readableBytes} then a buffer of length {@link #readableBytes} is returned.
* @param aggregatePromise used to aggregate the promises and listeners for the constituent buffers.
* @return a {@link ByteBuf} composed of the enqueued buffers.
*/
public final ByteBuf remove(ByteBufAllocator alloc, int bytes, ChannelPromise aggregatePromise) {
checkPositiveOrZero(bytes, "bytes");
checkNotNull(aggregatePromise, "aggregatePromise");
// Use isEmpty rather than readableBytes==0 as we may have a promise associated with an empty buffer.
if (bufAndListenerPairs.isEmpty()) {
assert readableBytes == 0;
return removeEmptyValue();
}
bytes = Math.min(bytes, readableBytes);
ByteBuf toReturn = null;
ByteBuf entryBuffer = null;
int originalBytes = bytes;
try {
for (;;) {
Object entry = bufAndListenerPairs.poll();
if (entry == null) {
break;
}
// fast-path vs abstract type
if (entry instanceof ByteBuf) {
entryBuffer = (ByteBuf) entry;
int bufferBytes = entryBuffer.readableBytes();
if (bufferBytes > bytes) {
// Add the buffer back to the queue as we can't consume all of it.
bufAndListenerPairs.addFirst(entryBuffer);
if (bytes > 0) {
// Take a slice of what we can consume and retain it.
entryBuffer = entryBuffer.readRetainedSlice(bytes);
// we end here, so if this is the only buffer to return, skip composing
toReturn = toReturn == null ? entryBuffer
: compose(alloc, toReturn, entryBuffer);
bytes = 0;
}
break;
}
bytes -= bufferBytes;
if (toReturn == null) {
// if there are no more bytes in the queue after this, there's no reason to compose
toReturn = bufferBytes == readableBytes
? entryBuffer
: composeFirst(alloc, entryBuffer);
} else {
toReturn = compose(alloc, toReturn, entryBuffer);
}
entryBuffer = null;
} else if (entry instanceof DelegatingChannelPromiseNotifier) {
aggregatePromise.addListener((DelegatingChannelPromiseNotifier) entry);
} else if (entry instanceof ChannelFutureListener) {
aggregatePromise.addListener((ChannelFutureListener) entry);
}
}
} catch (Throwable cause) {
safeRelease(entryBuffer);
safeRelease(toReturn);
aggregatePromise.setFailure(cause);
throwException(cause);
}
decrementReadableBytes(originalBytes - bytes);
return toReturn;
}
/**
* The number of readable bytes.
*/
public final int readableBytes() {
return readableBytes;
}
/**
* Are there pending buffers in the queue.
*/
public final boolean isEmpty() {
return bufAndListenerPairs.isEmpty();
}
/**
* Release all buffers in the queue and complete all listeners and promises.
*/
public final void releaseAndFailAll(ChannelOutboundInvoker invoker, Throwable cause) {
releaseAndCompleteAll(invoker.newFailedFuture(cause));
}
/**
* Copy all pending entries in this queue into the destination queue.
* @param dest to copy pending buffers to.
*/
public final void copyTo(AbstractCoalescingBufferQueue dest) {
dest.bufAndListenerPairs.addAll(bufAndListenerPairs);
dest.incrementReadableBytes(readableBytes);
}
/**
* Writes all remaining elements in this queue.
* @param ctx The context to write all elements to.
*/
public final void writeAndRemoveAll(ChannelHandlerContext ctx) {
Throwable pending = null;
ByteBuf previousBuf = null;
for (;;) {
Object entry = bufAndListenerPairs.poll();
try {
if (entry == null) {
if (previousBuf != null) {
decrementReadableBytes(previousBuf.readableBytes());
ctx.write(previousBuf, ctx.voidPromise());
}
break;
}
if (entry instanceof ByteBuf) {
if (previousBuf != null) {
decrementReadableBytes(previousBuf.readableBytes());
ctx.write(previousBuf, ctx.voidPromise());
}
previousBuf = (ByteBuf) entry;
} else if (entry instanceof ChannelPromise) {
decrementReadableBytes(previousBuf.readableBytes());
ctx.write(previousBuf, (ChannelPromise) entry);
previousBuf = null;
} else {
decrementReadableBytes(previousBuf.readableBytes());
ctx.write(previousBuf).addListener((ChannelFutureListener) entry);
previousBuf = null;
}
} catch (Throwable t) {
if (pending == null) {
pending = t;
} else {
logger.info("Throwable being suppressed because Throwable {} is already pending", pending, t);
}
}
}
if (pending != null) {
throw new IllegalStateException(pending);
}
}
@Override
public String toString() {
return "bytes: " + readableBytes + " buffers: " + (size() >> 1);
}
/**
* Calculate the result of {@code current + next}.
*/
protected abstract ByteBuf compose(ByteBufAllocator alloc, ByteBuf cumulation, ByteBuf next);
/**
* Compose {@code cumulation} and {@code next} into a new {@link CompositeByteBuf}.
*/
protected final ByteBuf composeIntoComposite(ByteBufAllocator alloc, ByteBuf cumulation, ByteBuf next) {
// Create a composite buffer to accumulate this pair and potentially all the buffers
// in the queue. Using +2 as we have already dequeued current and next.
CompositeByteBuf composite = alloc.compositeBuffer(size() + 2);
try {
composite.addComponent(true, cumulation);
composite.addComponent(true, next);
} catch (Throwable cause) {
composite.release();
safeRelease(next);
throwException(cause);
}
return composite;
}
/**
* Compose {@code cumulation} and {@code next} into a new {@link ByteBufAllocator#ioBuffer()}.
* @param alloc The allocator to use to allocate the new buffer.
* @param cumulation The current cumulation.
* @param next The next buffer.
* @return The result of {@code cumulation + next}.
*/
protected final ByteBuf copyAndCompose(ByteBufAllocator alloc, ByteBuf cumulation, ByteBuf next) {
ByteBuf newCumulation = alloc.ioBuffer(cumulation.readableBytes() + next.readableBytes());
try {
newCumulation.writeBytes(cumulation).writeBytes(next);
} catch (Throwable cause) {
newCumulation.release();
safeRelease(next);
throwException(cause);
}
cumulation.release();
next.release();
return newCumulation;
}
/**
* Calculate the first {@link ByteBuf} which will be used in subsequent calls to
* {@link #compose(ByteBufAllocator, ByteBuf, ByteBuf)}.
*/
protected ByteBuf composeFirst(ByteBufAllocator allocator, ByteBuf first) {
return first;
}
/**
* The value to return when {@link #remove(ByteBufAllocator, int, ChannelPromise)} is called but the queue is empty.
* @return the {@link ByteBuf} which represents an empty queue.
*/
protected abstract ByteBuf removeEmptyValue();
/**
* Get the number of elements in this queue added via one of the {@link #add(ByteBuf)} methods.
* @return the number of elements in this queue.
*/
protected final int size() {
return bufAndListenerPairs.size();
}
private void releaseAndCompleteAll(ChannelFuture future) {
Throwable pending = null;
for (;;) {
Object entry = bufAndListenerPairs.poll();
if (entry == null) {
break;
}
try {
if (entry instanceof ByteBuf) {
ByteBuf buffer = (ByteBuf) entry;
decrementReadableBytes(buffer.readableBytes());
safeRelease(buffer);
} else {
((ChannelFutureListener) entry).operationComplete(future);
}
} catch (Throwable t) {
if (pending == null) {
pending = t;
} else {
logger.info("Throwable being suppressed because Throwable {} is already pending", pending, t);
}
}
}
if (pending != null) {
throw new IllegalStateException(pending);
}
}
private void incrementReadableBytes(int increment) {
int nextReadableBytes = readableBytes + increment;
if (nextReadableBytes < readableBytes) {
throw new IllegalStateException("buffer queue length overflow: " + readableBytes + " + " + increment);
}
readableBytes = nextReadableBytes;
if (tracker != null) {
tracker.incrementPendingOutboundBytes(increment);
}
}
private void decrementReadableBytes(int decrement) {
readableBytes -= decrement;
assert readableBytes >= 0;
if (tracker != null) {
tracker.decrementPendingOutboundBytes(decrement);
}
}
private static ChannelFutureListener toChannelFutureListener(ChannelPromise promise) {
return promise.isVoid() ? null : new DelegatingChannelPromiseNotifier(promise);
}
}
