/*

 * Copyright (c) 2010, 2011, 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 6979009

 * @summary Ensure ClosedByInterruptException is thrown when I/O operation

 *     interrupted by Thread.interrupt

 * @key randomness

 */

import java.io.*;

import java.util.Random;

import java.nio.ByteBuffer;

import java.nio.channels.*;

public class ClosedByInterrupt {

    static final int K = 1024;

    static final Random rand = new Random();

    static volatile boolean failed;

    public static void main(String[] args) throws Exception {

        File f = File.createTempFile("blah", null);

        f.deleteOnExit();

        // create 1MB file.

        byte[] b = new byte[K*K];

        rand.nextBytes(b);

        ByteBuffer bb = ByteBuffer.wrap(b);

        try (FileChannel fc = new FileOutputStream(f).getChannel()) {

            while (bb.hasRemaining())

                fc.write(bb);

        }

        // test with 1-16 concurrent threads

        for (int i=1; i<=16; i++) {

            System.out.format("%d thread(s)%n", i);

            test(f, i);

            if (failed)

                break;

        }

        if (failed)

            throw new RuntimeException("Test failed");

    }

    /**

     * Starts "nThreads" that do I/O on the given file concurrently. Continuously

     * interrupts one of the threads to cause the file to be closed and

     * ClosedByInterruptException to be thrown. The other threads should "fail" with

     * ClosedChannelException (or the more specific AsynchronousCloseException).

     */

    static void test(File f, int nThreads) throws Exception {

        try (FileChannel fc = new RandomAccessFile(f, "rwd").getChannel()) {

            Thread[] threads = new Thread[nThreads];

            // start threads

            for (int i=0; i<nThreads; i++) {

                boolean interruptible = (i==0);

                ReaderWriter task = new ReaderWriter(fc, interruptible);

                Thread t = new Thread(task);

                t.start();

                threads[i] = t;

            }

            // give time for threads to start

            Thread.sleep(500 + rand.nextInt(1000));

            // interrupt thread until channel is closed

            while (fc.isOpen()) {

                threads[0].interrupt();

                Thread.sleep(rand.nextInt(50));

            }

            // wait for test to finish

            for (int i=0; i<nThreads; i++) {

                threads[i].join();

            }

        }

    }

    /**

     * A task that continuously reads or writes to random areas of a file

     * until the channel is closed. An "interruptible" task expects the

     * channel to be closed by an interupt, a "non-interruptible" thread

     * does not.

     */

    static class ReaderWriter implements Runnable {

        final FileChannel fc;

        final boolean interruptible;

        final boolean writer;

        ReaderWriter(FileChannel fc, boolean interruptible) {

            this.fc = fc;

            this.interruptible = interruptible;

            this.writer = rand.nextBoolean();

        }

        public void run() {

            ByteBuffer bb = ByteBuffer.allocate(K);

            if (writer)

                rand.nextBytes(bb.array());

            try {

                for (;;) {

                    long position = rand.nextInt(K*K - bb.capacity());

                    if (writer) {

                        bb.position(0).limit(bb.capacity());

                        fc.write(bb, position);

                    } else {

                        bb.clear();

                        fc.read(bb, position);

                    }

                    if (!interruptible) {

                        // give the interruptible thread a chance

                        try {

                            Thread.sleep(rand.nextInt(50));

                        } catch (InterruptedException e) {

                            unexpected(e);

                        }

                    }

                }

            } catch (ClosedByInterruptException e) {

                if (interruptible) {

                    if (Thread.interrupted()) {

                        expected(e + " thrown and interrupt status set");

                    } else {

                        unexpected(e + " thrown but interrupt status not set");

                    }

                } else {

                    unexpected(e);

                }

            } catch (ClosedChannelException e) {

                if (interruptible) {

                    unexpected(e);

                } else {

                    expected(e);

                }

            } catch (Exception e) {

                unexpected(e);

            }

        }

    }

    static void expected(Exception e) {

        System.out.format("%s (expected)%n", e);

    }

    static void expected(String msg) {

        System.out.format("%s (expected)%n", msg);

    }

    static void unexpected(Exception e) {

        System.err.format("%s (not expected)%n", e);

        failed = true;

    }

    static void unexpected(String msg) {

        System.err.println(msg);

        failed = true;

    }

}