| /* |
| * ==================================================================== |
| * 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, 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. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| */ |
| package org.apache.hc.core5.reactive; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.util.List; |
| import java.util.concurrent.BlockingQueue; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| import org.apache.hc.core5.annotation.Contract; |
| import org.apache.hc.core5.annotation.ThreadingBehavior; |
| import org.apache.hc.core5.http.Header; |
| import org.apache.hc.core5.http.HttpStreamResetException; |
| import org.apache.hc.core5.http.nio.AsyncDataConsumer; |
| import org.apache.hc.core5.http.nio.CapacityChannel; |
| import org.apache.hc.core5.util.Args; |
| import org.reactivestreams.Publisher; |
| import org.reactivestreams.Subscriber; |
| import org.reactivestreams.Subscription; |
| |
| /** |
| * An asynchronous data consumer that supports Reactive Streams. |
| * |
| * @since 5.0 |
| */ |
| @Contract(threading = ThreadingBehavior.SAFE) |
| final class ReactiveDataConsumer implements AsyncDataConsumer, Publisher<ByteBuffer> { |
| |
| private final AtomicLong requests = new AtomicLong(0); |
| |
| private final BlockingQueue<ByteBuffer> buffers = new LinkedBlockingQueue<>(); |
| private final AtomicBoolean flushInProgress = new AtomicBoolean(false); |
| private final Object flushLock = new Object(); |
| private final AtomicInteger windowScalingIncrement = new AtomicInteger(0); |
| private volatile boolean cancelled; |
| private volatile boolean completed; |
| private volatile Exception exception; |
| private volatile CapacityChannel capacityChannel; |
| private volatile Subscriber<? super ByteBuffer> subscriber; |
| |
| public void failed(final Exception cause) { |
| if (!completed) { |
| exception = cause; |
| flushToSubscriber(); |
| } |
| } |
| |
| @Override |
| public void updateCapacity(final CapacityChannel capacityChannel) throws IOException { |
| throwIfCancelled(); |
| this.capacityChannel = capacityChannel; |
| signalCapacity(capacityChannel); |
| } |
| |
| private void signalCapacity(final CapacityChannel channel) throws IOException { |
| final int increment = windowScalingIncrement.getAndSet(0); |
| if (increment > 0) { |
| channel.update(increment); |
| } |
| } |
| |
| private void throwIfCancelled() throws IOException { |
| if (cancelled) { |
| throw new HttpStreamResetException("Downstream subscriber to ReactiveDataConsumer cancelled"); |
| } |
| } |
| |
| @Override |
| public void consume(final ByteBuffer byteBuffer) throws IOException { |
| if (completed) { |
| throw new IllegalStateException("Received data past end of stream"); |
| } |
| throwIfCancelled(); |
| |
| final byte[] copy = new byte[byteBuffer.remaining()]; |
| byteBuffer.get(copy); |
| buffers.add(ByteBuffer.wrap(copy)); |
| |
| flushToSubscriber(); |
| } |
| |
| @Override |
| public void streamEnd(final List<? extends Header> trailers) { |
| completed = true; |
| flushToSubscriber(); |
| } |
| |
| @Override |
| public void releaseResources() { |
| this.capacityChannel = null; |
| } |
| |
| private void flushToSubscriber() { |
| synchronized (flushLock) { |
| final Subscriber<? super ByteBuffer> s = subscriber; |
| if (flushInProgress.getAndSet(true)) { |
| return; |
| } |
| try { |
| if (s == null) { |
| return; |
| } |
| if (exception != null) { |
| subscriber = null; |
| s.onError(exception); |
| return; |
| } |
| ByteBuffer next; |
| while (requests.get() > 0 && ((next = buffers.poll()) != null)) { |
| final int bytesFreed = next.remaining(); |
| s.onNext(next); |
| requests.decrementAndGet(); |
| windowScalingIncrement.addAndGet(bytesFreed); |
| } |
| final CapacityChannel localChannel = capacityChannel; |
| if (localChannel != null) { |
| try { |
| signalCapacity(localChannel); |
| } catch (final IOException e) { |
| exception = e; |
| s.onError(e); |
| return; |
| } |
| } |
| if (completed && buffers.isEmpty()) { |
| subscriber = null; |
| s.onComplete(); |
| } |
| } finally { |
| flushInProgress.set(false); |
| } |
| } |
| } |
| |
| @Override |
| public void subscribe(final Subscriber<? super ByteBuffer> subscriber) { |
| this.subscriber = Args.notNull(subscriber, "subscriber"); |
| subscriber.onSubscribe(new Subscription() { |
| @Override |
| public void request(final long increment) { |
| if (increment <= 0) { |
| failed(new IllegalArgumentException("The number of elements requested must be strictly positive")); |
| return; |
| } |
| requests.addAndGet(increment); |
| flushToSubscriber(); |
| } |
| |
| @Override |
| public void cancel() { |
| ReactiveDataConsumer.this.cancelled = true; |
| ReactiveDataConsumer.this.subscriber = null; |
| } |
| }); |
| } |
| } |