/*

 * Copyright (c) 2018, 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.

 *

 * 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.

 */

/* @test

 * @bug 8202252

 * @run testng CompletionHandlerRelease

 * @summary Verify that reference to CompletionHandler is cleared after use

 */

import java.io.Closeable;

import java.io.IOException;

import java.lang.ref.Reference;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.WeakReference;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import static java.net.StandardSocketOptions.*;

import java.nio.ByteBuffer;

import java.nio.channels.AsynchronousChannelGroup;

import java.nio.channels.AsynchronousServerSocketChannel;

import java.nio.channels.AsynchronousSocketChannel;

import java.nio.channels.CompletionHandler;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

import org.testng.annotations.AfterTest;

import org.testng.annotations.BeforeTest;

import org.testng.annotations.Test;

import static org.testng.Assert.*;

public class CompletionHandlerRelease {

    @Test

    public void testConnect() throws Exception {

        try (Server server = new Server()) {

            try (AsynchronousSocketChannel ch =

                 AsynchronousSocketChannel.open(GROUP)) {

                CountDownLatch latch = new CountDownLatch(1);

                Handler<Void,Object> handler =

                    new Handler<Void,Object>("connect", latch);

                ReferenceQueue queue = new ReferenceQueue<WeakReference>();

                WeakReference<Object> ref =

                    new WeakReference<Object>(handler, queue);

                ch.connect(server.address(), null, handler);

                try { latch.await(); } catch (InterruptedException ignore) { }

                handler = null;

                waitForRefToClear(ref, queue);

                server.accept().get().close();

            }

        }

    }

    @Test

    public void testWrite() throws Exception {

        try (Server server = new Server();

             AsynchronousSocketChannel ch =

                 AsynchronousSocketChannel.open(GROUP)) {

            ch.connect(server.address()).get();

            try (AsynchronousSocketChannel sc = server.accept().get()) {

                ByteBuffer src = ByteBuffer.wrap("hello".getBytes("UTF-8"));

                sc.setOption(SO_SNDBUF, src.remaining());

                CountDownLatch latch = new CountDownLatch(1);

                Handler<Integer,Object> handler =

                    new Handler<Integer,Object>("write", latch);

                ReferenceQueue queue = new ReferenceQueue<WeakReference>();

                WeakReference<Object> ref =

                    new WeakReference<Object>(handler, queue);

                sc.write(src, null, handler);

                try { latch.await(); } catch (InterruptedException ignore) { }

                handler = null;

                waitForRefToClear(ref, queue);

            }

        }

    }

    @Test

    public void testRead() throws Exception {

        try (Server server = new Server();

             AsynchronousSocketChannel ch =

                 AsynchronousSocketChannel.open(GROUP)) {

            ch.connect(server.address()).get();

            try (AsynchronousSocketChannel sc = server.accept().get()) {

                ByteBuffer src = ByteBuffer.wrap("hello".getBytes("UTF-8"));

                sc.setOption(SO_SNDBUF, src.remaining());

                sc.write(src).get();

                CountDownLatch latch = new CountDownLatch(1);

                Handler<Integer,Object> handler =

                    new Handler<Integer,Object>("read", latch);

                ReferenceQueue queue = new ReferenceQueue<WeakReference>();

                WeakReference<Object> ref =

                    new WeakReference<Object>(handler, queue);

                ByteBuffer dst = ByteBuffer.allocate(64);

                ch.read(dst, null, handler);

                try { latch.await(); } catch (InterruptedException ignore) { }

                handler = null;

                waitForRefToClear(ref, queue);

            }

        }

    }

    private AsynchronousChannelGroup GROUP;

    @BeforeTest

    void setup() throws IOException {

        GROUP = AsynchronousChannelGroup.withFixedThreadPool(2,

            Executors.defaultThreadFactory());

    }

    @AfterTest

    void cleanup() throws IOException {

        GROUP.shutdownNow();

    }

    class Server implements Closeable {

        private final AsynchronousServerSocketChannel ssc;

        private final InetSocketAddress address;

        Server() throws IOException {

            this(0);

        }

        Server(int recvBufSize) throws IOException {

            ssc = AsynchronousServerSocketChannel.open(GROUP);

            if (recvBufSize > 0) {

                ssc.setOption(SO_RCVBUF, recvBufSize);

            }

            ssc.bind(new InetSocketAddress(InetAddress.getLoopbackAddress(),

                0));

            address = (InetSocketAddress)ssc.getLocalAddress();

        }

        InetSocketAddress address() {

            return address;

        }

        Future<AsynchronousSocketChannel> accept() throws IOException {

            return ssc.accept();

        }

        public void close() throws IOException {

            ssc.close();

        }

    }

    static class Handler<V,A> implements CompletionHandler<V,A> {

        private final String name;

        private final CountDownLatch latch;

        Handler(String name, CountDownLatch latch) {

            this.name = name;

            this.latch = latch;

        }

        public void completed(V result, A attachment) {

            System.out.format("%s completed(%s, %s)%n",

                name, result, attachment);

            latch.countDown();

        }

        public void failed(Throwable exc, A attachment) {

            System.out.format("%s failed(%s, %s)%n",

                name, exc, attachment);

            exc.printStackTrace();

            latch.countDown();

        }

    }

    private void waitForRefToClear(Reference ref, ReferenceQueue queue)

        throws InterruptedException {

        Reference r;

        while ((r = queue.remove(20)) == null) {

            System.gc();

        }

        assertEquals(r, ref);

        assertNull(r.get());

    }

}