| /* |
| * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package jdk.incubator.http.internal.websocket; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.nio.channels.SelectionKey; |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| /* |
| * Receives incoming data from the channel on demand and converts it into a |
| * stream of WebSocket messages which are then delivered to the supplied message |
| * consumer in a strict sequential order and non-recursively. In other words, |
| * |
| * onText() |
| * onText() |
| * onBinary() |
| * ... |
| * |
| * instead of |
| * |
| * onText() |
| * onText() |
| * onBinary() |
| * ... |
| * |
| * even if `request(long n)` is called from inside these invocations. |
| */ |
| final class Receiver { |
| |
| private final MessageStreamConsumer messageConsumer; |
| private final RawChannel channel; |
| private final FrameConsumer frameConsumer; |
| private final Frame.Reader reader = new Frame.Reader(); |
| private final RawChannel.RawEvent event = createHandler(); |
| private final AtomicLong demand = new AtomicLong(); |
| private final CooperativeHandler handler; |
| |
| private ByteBuffer data; |
| private volatile int state; |
| |
| private static final int UNREGISTERED = 0; |
| private static final int AVAILABLE = 1; |
| private static final int WAITING = 2; |
| |
| Receiver(MessageStreamConsumer messageConsumer, RawChannel channel) { |
| this.messageConsumer = messageConsumer; |
| this.channel = channel; |
| this.frameConsumer = new FrameConsumer(this.messageConsumer); |
| this.data = channel.initialByteBuffer(); |
| // To ensure the initial non-final `data` will be visible |
| // (happens-before) when `handler` invokes `pushContinuously` |
| // the following assignment is done last: |
| handler = new CooperativeHandler(this::pushContinuously); |
| } |
| |
| private RawChannel.RawEvent createHandler() { |
| return new RawChannel.RawEvent() { |
| |
| @Override |
| public int interestOps() { |
| return SelectionKey.OP_READ; |
| } |
| |
| @Override |
| public void handle() { |
| state = AVAILABLE; |
| handler.handle(); |
| } |
| }; |
| } |
| |
| void request(long n) { |
| if (n < 0L) { |
| throw new IllegalArgumentException("Negative: " + n); |
| } |
| demand.accumulateAndGet(n, (p, i) -> p + i < 0 ? Long.MAX_VALUE : p + i); |
| handler.handle(); |
| } |
| |
| void acknowledge() { |
| long x = demand.decrementAndGet(); |
| if (x < 0) { |
| throw new InternalError(String.valueOf(x)); |
| } |
| } |
| |
| /* |
| * Stops the machinery from reading and delivering messages permanently, |
| * regardless of the current demand and data availability. |
| */ |
| void close() { |
| handler.stop(); |
| } |
| |
| private void pushContinuously() { |
| while (!handler.isStopped()) { |
| if (data.hasRemaining()) { |
| if (demand.get() > 0) { |
| try { |
| int oldPos = data.position(); |
| reader.readFrame(data, frameConsumer); |
| int newPos = data.position(); |
| assert oldPos != newPos : data; // reader always consumes bytes |
| } catch (FailWebSocketException e) { |
| handler.stop(); |
| messageConsumer.onError(e); |
| } |
| continue; |
| } |
| break; |
| } |
| switch (state) { |
| case WAITING: |
| return; |
| case UNREGISTERED: |
| try { |
| state = WAITING; |
| channel.registerEvent(event); |
| } catch (IOException e) { |
| handler.stop(); |
| messageConsumer.onError(e); |
| } |
| return; |
| case AVAILABLE: |
| try { |
| data = channel.read(); |
| } catch (IOException e) { |
| handler.stop(); |
| messageConsumer.onError(e); |
| return; |
| } |
| if (data == null) { // EOF |
| handler.stop(); |
| messageConsumer.onComplete(); |
| return; |
| } else if (!data.hasRemaining()) { // No data at the moment |
| // Pretty much a "goto", reusing the existing code path |
| // for registration |
| state = UNREGISTERED; |
| } |
| continue; |
| default: |
| throw new InternalError(String.valueOf(state)); |
| } |
| } |
| } |
| } |
| |