| /* |
| * ==================================================================== |
| * 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.ArrayDeque; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| import org.apache.hc.core5.annotation.Contract; |
| import org.apache.hc.core5.annotation.ThreadingBehavior; |
| import org.apache.hc.core5.http.HttpStreamResetException; |
| import org.apache.hc.core5.http.nio.AsyncDataProducer; |
| import org.apache.hc.core5.http.nio.DataStreamChannel; |
| import org.apache.hc.core5.util.Args; |
| import org.reactivestreams.Publisher; |
| import org.reactivestreams.Subscriber; |
| import org.reactivestreams.Subscription; |
| |
| /** |
| * An asynchronous data producer that supports Reactive Streams. |
| * |
| * @since 5.0 |
| */ |
| @Contract(threading = ThreadingBehavior.SAFE) |
| final class ReactiveDataProducer implements AsyncDataProducer, Subscriber<ByteBuffer> { |
| |
| private static final int BUFFER_WINDOW_SIZE = 5; |
| |
| private final AtomicReference<DataStreamChannel> requestChannel = new AtomicReference<>(); |
| private final AtomicReference<Throwable> exception = new AtomicReference<>(null); |
| private final AtomicBoolean complete = new AtomicBoolean(false); |
| private final Publisher<ByteBuffer> publisher; |
| private final AtomicReference<Subscription> subscription = new AtomicReference<>(null); |
| private final ArrayDeque<ByteBuffer> buffers = new ArrayDeque<>(); // This field requires synchronization |
| |
| public ReactiveDataProducer(final Publisher<ByteBuffer> publisher) { |
| this.publisher = Args.notNull(publisher, "publisher"); |
| } |
| |
| void setChannel(final DataStreamChannel channel) { |
| requestChannel.set(channel); |
| } |
| |
| @Override |
| public void onSubscribe(final Subscription subscription) { |
| if (this.subscription.getAndSet(subscription) != null) { |
| throw new IllegalStateException("Already subscribed"); |
| } |
| |
| subscription.request(BUFFER_WINDOW_SIZE); |
| } |
| |
| @Override |
| public void onNext(final ByteBuffer byteBuffer) { |
| final byte[] copy = new byte[byteBuffer.remaining()]; |
| byteBuffer.get(copy); |
| synchronized (buffers) { |
| buffers.add(ByteBuffer.wrap(copy)); |
| } |
| signalReadiness(); |
| } |
| |
| @Override |
| public void onError(final Throwable throwable) { |
| subscription.set(null); |
| exception.set(throwable); |
| signalReadiness(); |
| } |
| |
| @Override |
| public void onComplete() { |
| subscription.set(null); |
| complete.set(true); |
| signalReadiness(); |
| } |
| |
| private void signalReadiness() { |
| final DataStreamChannel channel = requestChannel.get(); |
| if (channel == null) { |
| throw new IllegalStateException("Output channel is not set"); |
| } |
| channel.requestOutput(); |
| } |
| |
| @Override |
| public int available() { |
| if (exception.get() != null || complete.get()) { |
| return 1; |
| } else { |
| synchronized (buffers) { |
| int sum = 0; |
| for (final ByteBuffer buffer : buffers) { |
| sum += buffer.remaining(); |
| } |
| return sum; |
| } |
| } |
| } |
| |
| @Override |
| public void produce(final DataStreamChannel channel) throws IOException { |
| if (requestChannel.get() == null) { |
| requestChannel.set(channel); |
| publisher.subscribe(this); |
| } |
| |
| final Throwable t = exception.get(); |
| final Subscription s = subscription.get(); |
| int buffersToReplenish = 0; |
| try { |
| synchronized (buffers) { |
| if (t != null) { |
| throw new HttpStreamResetException(t.getMessage(), t); |
| } else if (this.complete.get() && buffers.isEmpty()) { |
| channel.endStream(); |
| } else { |
| while (!buffers.isEmpty()) { |
| final ByteBuffer nextBuffer = buffers.remove(); |
| channel.write(nextBuffer); |
| if (nextBuffer.remaining() > 0) { |
| buffers.push(nextBuffer); |
| break; |
| } else if (s != null) { |
| // We defer the #request call until after we release the buffer lock. |
| buffersToReplenish++; |
| } |
| } |
| } |
| } |
| } finally { |
| if (s != null && buffersToReplenish > 0) { |
| s.request(buffersToReplenish); |
| } |
| } |
| } |
| |
| @Override |
| public void releaseResources() { |
| final Subscription s = subscription.getAndSet(null); |
| if (s != null) { |
| s.cancel(); |
| } |
| } |
| } |