jdk/src/java.httpclient/share/classes/java/net/http/WSReceiver.java
changeset 37874 02589df0999a
child 38856 cc3a0d1e96e0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.httpclient/share/classes/java/net/http/WSReceiver.java	Mon May 09 23:33:09 2016 +0100
@@ -0,0 +1,275 @@
+/*
+ * Copyright (c) 2016, 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 java.net.http;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.net.ProtocolException;
+import java.net.http.WebSocket.Listener;
+import java.nio.ByteBuffer;
+import java.nio.channels.SelectionKey;
+import java.util.Optional;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Supplier;
+
+import static java.lang.System.Logger.Level.ERROR;
+import static java.net.http.WSUtils.EMPTY_BYTE_BUFFER;
+import static java.net.http.WSUtils.logger;
+
+/*
+ * Receives incoming data from the channel and converts it into a sequence of
+ * messages, which are then passed to the listener.
+ */
+final class WSReceiver {
+
+    private final Listener listener;
+    private final WebSocket webSocket;
+    private final Supplier<WSShared<ByteBuffer>> buffersSupplier =
+            new WSSharedPool<>(() -> ByteBuffer.allocateDirect(32768), 2);
+    private final RawChannel channel;
+    private final RawChannel.NonBlockingEvent channelEvent;
+    private final WSSignalHandler handler;
+    private final AtomicLong demand = new AtomicLong();
+    private final AtomicBoolean readable = new AtomicBoolean();
+    private boolean started;
+    private volatile boolean closed;
+    private final WSFrame.Reader reader = new WSFrame.Reader();
+    private final WSFrameConsumer frameConsumer;
+    private WSShared<ByteBuffer> buf = WSShared.wrap(EMPTY_BYTE_BUFFER);
+    private WSShared<ByteBuffer> data; // TODO: initialize with leftovers from the RawChannel
+
+    WSReceiver(Listener listener, WebSocket webSocket, Executor executor,
+               RawChannel channel) {
+        this.listener = listener;
+        this.webSocket = webSocket;
+        this.channel = channel;
+        handler = new WSSignalHandler(executor, this::react);
+        channelEvent = createChannelEvent();
+        this.frameConsumer = new WSFrameConsumer(new MessageConsumer());
+    }
+
+    private void react() {
+        synchronized (this) {
+            while (demand.get() > 0 && !closed) {
+                try {
+                    if (data == null) {
+                        if (!getData()) {
+                            break;
+                        }
+                    }
+                    reader.readFrame(data, frameConsumer);
+                    if (!data.hasRemaining()) {
+                        data.dispose();
+                        data = null;
+                    }
+                    // In case of exception we don't need to clean any state,
+                    // since it's the terminal condition anyway. Nothing will be
+                    // retried.
+                } catch (WSProtocolException e) {
+                    // Translate into ProtocolException
+                    closeExceptionally(new ProtocolException().initCause(e));
+                } catch (Exception e) {
+                    closeExceptionally(e);
+                }
+            }
+        }
+    }
+
+    long request(long n) {
+        long newDemand = demand.accumulateAndGet(n, (p, i) -> p + i < 0 ? Long.MAX_VALUE : p + i);
+        handler.signal();
+        assert newDemand >= 0 : newDemand;
+        return newDemand;
+    }
+
+    private boolean getData() throws IOException {
+        if (!readable.get()) {
+            return false;
+        }
+        if (!buf.hasRemaining()) {
+            buf.dispose();
+            buf = buffersSupplier.get();
+            assert buf.hasRemaining() : buf;
+        }
+        int oldPosition = buf.position();
+        int oldLimit = buf.limit();
+        int numRead = channel.read(buf.buffer());
+        if (numRead > 0) {
+            data = buf.share(oldPosition, oldPosition + numRead);
+            buf.select(buf.limit(), oldLimit); // Move window to the free region
+            return true;
+        } else if (numRead == 0) {
+            readable.set(false);
+            channel.registerEvent(channelEvent);
+            return false;
+        } else {
+            assert numRead < 0 : numRead;
+            throw new WSProtocolException
+                    ("7.2.1.", "Stream ended before a Close frame has been received");
+        }
+    }
+
+    void start() {
+        synchronized (this) {
+            if (started) {
+                throw new IllegalStateException("Already started");
+            }
+            started = true;
+            try {
+                channel.registerEvent(channelEvent);
+            } catch (IOException e) {
+                throw new UncheckedIOException(e);
+            }
+            try {
+                listener.onOpen(webSocket);
+            } catch (Exception e) {
+                closeExceptionally(new RuntimeException("onOpen threw an exception", e));
+            }
+        }
+    }
+
+    private void close() { // TODO: move to WS.java
+        closed = true;
+    }
+
+    private void closeExceptionally(Throwable error) {  // TODO: move to WS.java
+        close();
+        try {
+            listener.onError(webSocket, error);
+        } catch (Exception e) {
+            logger.log(ERROR, "onError threw an exception", e);
+        }
+    }
+
+    private final class MessageConsumer implements WSMessageConsumer {
+
+        @Override
+        public void onText(WebSocket.MessagePart part, WSDisposableText data) {
+            decrementDemand();
+            CompletionStage<?> cs;
+            try {
+                cs = listener.onText(webSocket, data, part);
+            } catch (Exception e) {
+                closeExceptionally(new RuntimeException("onText threw an exception", e));
+                return;
+            }
+            follow(cs, data, "onText");
+        }
+
+        @Override
+        public void onBinary(WebSocket.MessagePart part, WSShared<ByteBuffer> data) {
+            decrementDemand();
+            CompletionStage<?> cs;
+            try {
+                cs = listener.onBinary(webSocket, data.buffer(), part);
+            } catch (Exception e) {
+                closeExceptionally(new RuntimeException("onBinary threw an exception", e));
+                return;
+            }
+            follow(cs, data, "onBinary");
+        }
+
+        @Override
+        public void onPing(WSShared<ByteBuffer> data) {
+            decrementDemand();
+            CompletionStage<?> cs;
+            try {
+                cs = listener.onPing(webSocket, data.buffer());
+            } catch (Exception e) {
+                closeExceptionally(new RuntimeException("onPing threw an exception", e));
+                return;
+            }
+            follow(cs, data, "onPing");
+        }
+
+        @Override
+        public void onPong(WSShared<ByteBuffer> data) {
+            decrementDemand();
+            CompletionStage<?> cs;
+            try {
+                cs = listener.onPong(webSocket, data.buffer());
+            } catch (Exception e) {
+                closeExceptionally(new RuntimeException("onPong threw an exception", e));
+                return;
+            }
+            follow(cs, data, "onPong");
+        }
+
+        @Override
+        public void onClose(WebSocket.CloseCode code, CharSequence reason) {
+            decrementDemand();
+            try {
+                close();
+                listener.onClose(webSocket, Optional.ofNullable(code), reason.toString());
+            } catch (Exception e) {
+                logger.log(ERROR, "onClose threw an exception", e);
+            }
+        }
+    }
+
+    private void follow(CompletionStage<?> cs, WSDisposable d, String source) {
+        if (cs == null) {
+            d.dispose();
+        } else {
+            cs.whenComplete((whatever, error) -> {
+                if (error != null) {
+                    String m = "CompletionStage returned by " + source + " completed exceptionally";
+                    closeExceptionally(new RuntimeException(m, error));
+                }
+                d.dispose();
+            });
+        }
+    }
+
+    private void decrementDemand() {
+        long newDemand = demand.decrementAndGet();
+        assert newDemand >= 0 : newDemand;
+    }
+
+    private RawChannel.NonBlockingEvent createChannelEvent() {
+        return new RawChannel.NonBlockingEvent() {
+
+            @Override
+            public int interestOps() {
+                return SelectionKey.OP_READ;
+            }
+
+            @Override
+            public void handle() {
+                boolean wasNotReadable = readable.compareAndSet(false, true);
+                assert wasNotReadable;
+                handler.signal();
+            }
+
+            @Override
+            public String toString() {
+                return "Read readiness event [" + channel + "]";
+            }
+        };
+    }
+}