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 * 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.
 *
 * 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
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 * questions.
 */

/* @test
 * @bug 6834246 6842687
 * @summary Stress test connections through the loopback interface
 * @run main StressLoopback
 * @run main/othervm -Djdk.net.useFastTcpLoopback StressLoopback
 * @key randomness
 */

import java.nio.ByteBuffer;
import java.net.*;
import java.nio.channels.*;
import java.util.Random;
import java.io.IOException;

public class StressLoopback {
    static final Random rand = new Random();

    public static void main(String[] args) throws Exception {
        // setup listener
        AsynchronousServerSocketChannel listener =
            AsynchronousServerSocketChannel.open().bind(new InetSocketAddress(0));
        int port =((InetSocketAddress)(listener.getLocalAddress())).getPort();
        InetAddress lh = InetAddress.getLocalHost();
        SocketAddress remote = new InetSocketAddress(lh, port);

        // create sources and sinks
        int count = 2 + rand.nextInt(9);
        Source[] source = new Source[count];
        Sink[] sink = new Sink[count];
        for (int i=0; i<count; i++) {
            AsynchronousSocketChannel ch = AsynchronousSocketChannel.open();
            ch.connect(remote).get();
            source[i] = new Source(ch);
            sink[i] = new Sink(listener.accept().get());
        }

        // start the sinks and sources
        for (int i=0; i<count; i++) {
            sink[i].start();
            source[i].start();
        }

        // let the test run for a while
        Thread.sleep(20*1000);

        // wait until everyone is done
        boolean failed = false;
        long total = 0L;
        for (int i=0; i<count; i++) {
            long nwrote = source[i].finish();
            long nread = sink[i].finish();
            if (nread != nwrote)
                failed = true;
            System.out.format("%d -> %d (%s)\n",
                nwrote, nread, (failed) ? "FAIL" : "PASS");
            total += nwrote;
        }
        if (failed)
            throw new RuntimeException("Test failed - see log for details");
        System.out.format("Total sent %d MB\n", total / (1024L * 1024L));
    }

    /**
     * Writes bytes to a channel until "done". When done the channel is closed.
     */
    static class Source {
        private final AsynchronousByteChannel channel;
        private final ByteBuffer sentBuffer;
        private volatile long bytesSent;
        private volatile boolean finished;

        Source(AsynchronousByteChannel channel) {
            this.channel = channel;
            int size = 1024 + rand.nextInt(10000);
            this.sentBuffer = (rand.nextBoolean()) ?
                ByteBuffer.allocateDirect(size) : ByteBuffer.allocate(size);
        }

        void start() {
            sentBuffer.position(0);
            sentBuffer.limit(sentBuffer.capacity());
            channel.write(sentBuffer, (Void)null, new CompletionHandler<Integer,Void> () {
                public void completed(Integer nwrote, Void att) {
                    bytesSent += nwrote;
                    if (finished) {
                        closeUnchecked(channel);
                    } else {
                        sentBuffer.position(0);
                        sentBuffer.limit(sentBuffer.capacity());
                        channel.write(sentBuffer, (Void)null, this);
                    }
                }
                public void failed(Throwable exc, Void att) {
                    exc.printStackTrace();
                    closeUnchecked(channel);
                }
            });
        }

        long finish() {
            finished = true;
            waitUntilClosed(channel);
            return bytesSent;
        }
    }

    /**
     * Read bytes from a channel until EOF is received.
     */
    static class Sink {
        private final AsynchronousByteChannel channel;
        private final ByteBuffer readBuffer;
        private volatile long bytesRead;

        Sink(AsynchronousByteChannel channel) {
            this.channel = channel;
            int size = 1024 + rand.nextInt(10000);
            this.readBuffer = (rand.nextBoolean()) ?
                ByteBuffer.allocateDirect(size) : ByteBuffer.allocate(size);
        }

        void start() {
            channel.read(readBuffer, (Void)null, new CompletionHandler<Integer,Void> () {
                public void completed(Integer nread, Void att) {
                    if (nread < 0) {
                        closeUnchecked(channel);
                    } else {
                        bytesRead += nread;
                        readBuffer.clear();
                        channel.read(readBuffer, (Void)null, this);
                    }
                }
                public void failed(Throwable exc, Void att) {
                    exc.printStackTrace();
                    closeUnchecked(channel);
                }
            });
        }

        long finish() {
            waitUntilClosed(channel);
            return bytesRead;
        }
    }

    static void waitUntilClosed(Channel c) {
        while (c.isOpen()) {
            try {
                Thread.sleep(100);
            } catch (InterruptedException ignore) { }
        }
    }

    static void closeUnchecked(Channel c) {
        try {
            c.close();
        } catch (IOException ignore) { }
    }
}