/*

 * 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 4607272 6822643 6830721 6842687

 * @summary Unit test for AsynchronousFileChannel

 */

import java.nio.file.*;

import java.nio.channels.*;

import java.nio.ByteBuffer;

import java.io.File;

import java.io.IOException;

import java.util.*;

import java.util.concurrent.*;

import java.util.concurrent.atomic.AtomicReference;

import static java.nio.file.StandardOpenOption.*;

public class Basic {

    private static final Random rand = new Random();

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

        // create temporary file

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

        blah.deleteOnExit();

        AsynchronousFileChannel ch = AsynchronousFileChannel

            .open(blah.toPath(), READ, WRITE);

        try {

            // run tests

            testUsingCompletionHandlers(ch);

            testUsingWaitOnResult(ch);

            testInterruptHandlerThread(ch);

        } finally {

            ch.close();

        }

        // run test that expects channel to be closed

        testClosedChannel(ch);

        // these tests open the file themselves

        testLocking(blah.toPath());

        testCustomThreadPool(blah.toPath());

        testAsynchronousClose(blah.toPath());

        testCancel(blah.toPath());

        testTruncate(blah.toPath());

        // eagerly clean-up

        blah.delete();

    }

    /*

     * Generate buffer with random contents

     * Writes buffer to file using a CompletionHandler to consume the result

     *    of each write operation

     * Reads file to EOF to a new buffer using a CompletionHandler to consume

     *    the result of each read operation

     * Compares buffer contents

     */

    static void testUsingCompletionHandlers(AsynchronousFileChannel ch)

        throws IOException

    {

        System.out.println("testUsingCompletionHandlers");

        ch.truncate(0L);

        // generate buffer with random elements and write it to file

        ByteBuffer src = genBuffer();

        writeFully(ch, src, 0L);

        // read to EOF or buffer is full

        ByteBuffer dst = (rand.nextBoolean()) ?

            ByteBuffer.allocateDirect(src.capacity()) :

            ByteBuffer.allocate(src.capacity());

        readAll(ch, dst, 0L);

        // check buffers are the same

        src.flip();

        dst.flip();

        if (!src.equals(dst)) {

            throw new RuntimeException("Contents differ");

        }

    }

    /*

     * Generate buffer with random contents

     * Writes buffer to file, invoking the Future's get method to wait for

     *    each write operation to complete

     * Reads file to EOF to a new buffer, invoking the Future's get method to

     *    wait for each write operation to complete

     * Compares buffer contents

     */

    static void testUsingWaitOnResult(AsynchronousFileChannel ch)

        throws IOException

    {

        System.out.println("testUsingWaitOnResult");

        ch.truncate(0L);

        // generate buffer

        ByteBuffer src = genBuffer();

        // write buffer completely to file

        long position = 0L;

        while (src.hasRemaining()) {

            Future<Integer> result = ch.write(src, position);

            try {

                int n = result.get();

                // update position

                position += n;

            } catch (ExecutionException x) {

                throw new RuntimeException(x.getCause());

            } catch (InterruptedException x) {

                throw new RuntimeException(x);

            }

        }

        // read file into new buffer

        ByteBuffer dst = (rand.nextBoolean()) ?

            ByteBuffer.allocateDirect(src.capacity()) :

            ByteBuffer.allocate(src.capacity());

        position = 0L;

        int n;

        do {

            Future<Integer> result = ch.read(dst, position);

            try {

                n = result.get();

                // update position

                if (n > 0) position += n;

            } catch (ExecutionException x) {

                throw new RuntimeException(x.getCause());

            } catch (InterruptedException x) {

                throw new RuntimeException(x);

            }

        } while (n > 0);

        // check buffers are the same

        src.flip();

        dst.flip();

        if (!src.equals(dst)) {

            throw new RuntimeException("Contents differ");

        }

    }

    // exercise lock methods

    static void testLocking(Path file) throws IOException {

        System.out.println("testLocking");

        AsynchronousFileChannel ch = AsynchronousFileChannel

            .open(file, READ, WRITE);

        FileLock fl;

        try {

            // test 1 - acquire lock and check that tryLock throws

            // OverlappingFileLockException

            try {

                fl = ch.lock().get();

            } catch (ExecutionException x) {

                throw new RuntimeException(x);

            } catch (InterruptedException x) {

                throw new RuntimeException("Should not be interrupted");

            }

            if (!fl.acquiredBy().equals(ch))

                throw new RuntimeException("FileLock#acquiredBy returned incorrect channel");

            try {

                ch.tryLock();

                throw new RuntimeException("OverlappingFileLockException expected");

            } catch (OverlappingFileLockException x) {

            }

            fl.release();

            // test 2 - acquire try and check that lock throws OverlappingFileLockException

            fl = ch.tryLock();

            if (fl == null)

                throw new RuntimeException("Unable to acquire lock");

            try {

                ch.lock((Void)null, new CompletionHandler<FileLock,Void> () {

                    public void completed(FileLock result, Void att) {

                    }

                    public void failed(Throwable exc, Void att) {

                    }

                });

                throw new RuntimeException("OverlappingFileLockException expected");

            } catch (OverlappingFileLockException x) {

            }

        } finally {

            ch.close();

        }

        // test 3 - channel is closed so FileLock should no longer be valid

        if (fl.isValid())

            throw new RuntimeException("FileLock expected to be invalid");

    }

    // interrupt should not close channel

    static void testInterruptHandlerThread(final AsynchronousFileChannel ch) {

        System.out.println("testInterruptHandlerThread");

        ByteBuffer buf = ByteBuffer.allocateDirect(100);

        final CountDownLatch latch = new CountDownLatch(1);

        ch.read(buf, 0L, (Void)null, new CompletionHandler<Integer,Void>() {

            public void completed(Integer result, Void att) {

                try {

                    Thread.currentThread().interrupt();

                    long size = ch.size();

                    latch.countDown();

                } catch (IOException x) {

                    x.printStackTrace();

                }

            }

            public void failed(Throwable exc, Void att) {

            }

        });

        // wait for handler to complete

        await(latch);

    }

    // invoke method on closed channel

    static void testClosedChannel(AsynchronousFileChannel ch) {

        System.out.println("testClosedChannel");

        if (ch.isOpen())

            throw new RuntimeException("Channel should be closed");

        ByteBuffer buf = ByteBuffer.allocateDirect(100);

        // check read fails with ClosedChannelException

        try {

            ch.read(buf, 0L).get();

            throw new RuntimeException("ExecutionException expected");

        } catch (ExecutionException x) {

            if (!(x.getCause() instanceof ClosedChannelException))

                throw new RuntimeException("Cause of ClosedChannelException expected");

        } catch (InterruptedException x) {

        }

        // check write fails with ClosedChannelException

        try {

            ch.write(buf, 0L).get();

            throw new RuntimeException("ExecutionException expected");

        } catch (ExecutionException x) {

            if (!(x.getCause() instanceof ClosedChannelException))

                throw new RuntimeException("Cause of ClosedChannelException expected");

        } catch (InterruptedException x) {

        }

        // check lock fails with ClosedChannelException

        try {

            ch.lock().get();

            throw new RuntimeException("ExecutionException expected");

        } catch (ExecutionException x) {

            if (!(x.getCause() instanceof ClosedChannelException))

                throw new RuntimeException("Cause of ClosedChannelException expected");

        } catch (InterruptedException x) {

        }

    }

    // exercise custom thread pool

    static void testCustomThreadPool(Path file) throws IOException {

        System.out.println("testCustomThreadPool");

        // records threads that are created

        final List<Thread> threads = new ArrayList<Thread>();

        ThreadFactory threadFactory = new ThreadFactory() {

             @Override

             public Thread newThread(Runnable r) {

                 Thread t = new Thread(r);

                 t.setDaemon(true);

                 synchronized (threads) {

                     threads.add(t);

                 }

                 return t;

             }

        };

        // exercise tests with varied number of threads

        for (int nThreads=1; nThreads<=5; nThreads++) {

            synchronized (threads) {

                threads.clear();

            }

            ExecutorService executor = Executors.newFixedThreadPool(nThreads, threadFactory);

            Set<StandardOpenOption> opts = EnumSet.of(WRITE);

            AsynchronousFileChannel ch = AsynchronousFileChannel.open(file, opts, executor);

            try {

                for (int i=0; i<10; i++) {

                    // do I/O operation to see which thread invokes the completion handler

                    final AtomicReference<Thread> invoker = new AtomicReference<Thread>();

                    final CountDownLatch latch = new CountDownLatch(1);

                    ch.write(genBuffer(), 0L, (Void)null, new CompletionHandler<Integer,Void>() {

                        public void completed(Integer result, Void att) {

                            invoker.set(Thread.currentThread());

                            latch.countDown();

                        }

                        public void failed(Throwable exc, Void att) {

                        }

                    });

                    await(latch);

                    // check invoker

                    boolean found = false;

                    synchronized (threads) {

                        for (Thread t: threads) {

                            if (t == invoker.get()) {

                                found = true;

                                break;

                            }

                        }

                    }

                    if (!found)

                        throw new RuntimeException("Invoker thread not found");

                }

            } finally {

                ch.close();

                executor.shutdown();

            }

        }

        // test sharing a thread pool between many channels

        ExecutorService executor = Executors

            .newFixedThreadPool(1+rand.nextInt(10), threadFactory);

        final int n = 50 + rand.nextInt(50);

        AsynchronousFileChannel[] channels = new AsynchronousFileChannel[n];

        try {

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

                Set<StandardOpenOption> opts = EnumSet.of(WRITE);

                channels[i] = AsynchronousFileChannel.open(file, opts, executor);

                final CountDownLatch latch = new CountDownLatch(1);

                channels[i].write(genBuffer(), 0L, (Void)null, new CompletionHandler<Integer,Void>() {

                    public void completed(Integer result, Void att) {

                        latch.countDown();

                    }

                    public void failed(Throwable exc, Void att) {

                    }

                });

                await(latch);

                // close ~half the channels

                if (rand.nextBoolean())

                    channels[i].close();

            }

        } finally {

            // close remaining channels

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

                if (channels[i] != null) channels[i].close();

            }

            executor.shutdown();

        }

    }

    // exercise asynchronous close

    static void testAsynchronousClose(Path file) throws IOException {

        System.out.println("testAsynchronousClose");

        // create file

        AsynchronousFileChannel ch = AsynchronousFileChannel

            .open(file, WRITE, TRUNCATE_EXISTING);

        long size = 0L;

        do {

            ByteBuffer buf = genBuffer();

            int n = buf.remaining();

            writeFully(ch, buf, size);

            size += n;

        } while (size < (50L * 1024L * 1024L));

        ch.close();

        ch = AsynchronousFileChannel.open(file, WRITE, SYNC);

        // randomize number of writers, buffer size, and positions

        int nwriters = 1 + rand.nextInt(8);

        ByteBuffer[] buf = new ByteBuffer[nwriters];

        long[] position = new long[nwriters];

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

            buf[i] = genBuffer();

            position[i] = rand.nextInt((int)size);

        }

        // initiate I/O

        Future[] result = new Future[nwriters];

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

            result[i] = ch.write(buf[i], position[i]);

        }

        // close file

        ch.close();

        // write operations should complete or fail with AsynchronousCloseException

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

            try {

                result[i].get();

            } catch (ExecutionException x) {

                Throwable cause = x.getCause();

                if (!(cause instanceof AsynchronousCloseException))

                    throw new RuntimeException(cause);

            } catch (CancellationException  x) {

                throw new RuntimeException(x);   // should not happen

            } catch (InterruptedException x) {

                throw new RuntimeException(x);   // should not happen

            }

        }

    }

    // exercise cancel method

    static void testCancel(Path file) throws IOException {

        System.out.println("testCancel");

        for (int i=0; i<2; i++) {

            boolean mayInterruptIfRunning = (i == 0) ? false : true;

            // open with SYNC option to improve chances that write will not

            // complete immediately

            AsynchronousFileChannel ch = AsynchronousFileChannel

                .open(file, WRITE, SYNC);

            // start write operation

            Future<Integer> res = ch.write(genBuffer(), 0L);

            // cancel operation

            boolean cancelled = res.cancel(mayInterruptIfRunning);

            // check post-conditions

            if (!res.isDone())

                throw new RuntimeException("isDone should return true");

            if (res.isCancelled() != cancelled)

                throw new RuntimeException("isCancelled not consistent");

            try {

                res.get();

                if (cancelled)

                    throw new RuntimeException("CancellationException expected");

            } catch (CancellationException x) {

                if (!cancelled)

                    throw new RuntimeException("CancellationException not expected");

            } catch (ExecutionException x) {

                throw new RuntimeException(x);

            } catch (InterruptedException x) {

                throw new RuntimeException(x);

            }

            try {

                res.get(1, TimeUnit.SECONDS);

                if (cancelled)

                    throw new RuntimeException("CancellationException expected");

            } catch (CancellationException x) {

                if (!cancelled)

                    throw new RuntimeException("CancellationException not expected");

            } catch (ExecutionException x) {

                throw new RuntimeException(x);

            } catch (TimeoutException x) {

                throw new RuntimeException(x);

            } catch (InterruptedException x) {

                throw new RuntimeException(x);

            }

            ch.close();

        }

    }

    // exercise truncate method

    static void testTruncate(Path file) throws IOException {

        System.out.println("testTruncate");

        // basic tests

        AsynchronousFileChannel ch = AsynchronousFileChannel

            .open(file, CREATE, WRITE, TRUNCATE_EXISTING);

        try {

            writeFully(ch, genBuffer(), 0L);

            long size = ch.size();

            // attempt to truncate to a size greater than the current size

            if (ch.truncate(size + 1L).size() != size)

                throw new RuntimeException("Unexpected size after truncation");

            // truncate file

            if (ch.truncate(size - 1L).size() != (size - 1L))

                throw new RuntimeException("Unexpected size after truncation");

            // invalid size

            try {

                ch.truncate(-1L);

                throw new RuntimeException("IllegalArgumentException expected");

            } catch (IllegalArgumentException e) { }

        } finally {

            ch.close();

        }

        // channel is closed

        try {

            ch.truncate(0L);

            throw new RuntimeException("ClosedChannelException expected");

        } catch (ClosedChannelException  e) { }