/*

 * Copyright (c) 2007, 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

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 * questions.

 */

/**

 *

 * @test

 * @modules java.base/java.io:open

 * @bug 6524062

 * @summary Test to ensure that FIS.finalize() invokes the close() method as per

 * the specification.

 * @run main/othervm UnreferencedFISClosesFd

 */

import java.io.File;

import java.io.FileDescriptor;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.lang.management.ManagementFactory;

import java.lang.management.OperatingSystemMXBean;

import java.lang.ref.Reference;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.WeakReference;

import java.lang.reflect.Field;

import java.util.HashSet;

import java.util.concurrent.atomic.AtomicInteger;

import com.sun.management.UnixOperatingSystemMXBean;

/**

 * Tests for FIS unreferenced.

 *  - Not subclassed - cleaner cleanup

 *  - Subclassed no finalize or close - cleaner cleanup

 *  - Subclassed close overridden - AltFinalizer cleanup

 *  - Subclasses finalize overridden - cleaner cleanup

 *  - Subclasses finalize and close overridden - AltFinalizer cleanup

 */

public class UnreferencedFISClosesFd {

    enum CleanupType {

        CLOSE,      // Cleanup is handled via calling close

        CLEANER}    // Cleanup is handled via Cleaner

    static final String FILE_NAME = "empty.txt";

    /**

     * Subclass w/ no overrides; not finalize or close.

     * Cleanup should be via the Cleaner (not close).

     */

    public static class StreamOverrides extends FileInputStream {

        protected final AtomicInteger closeCounter;

        public StreamOverrides(String name) throws FileNotFoundException {

            super(name);

            closeCounter = new AtomicInteger(0);

        }

        final AtomicInteger closeCounter() {

            return closeCounter;

        }

    }

    /**

     * Subclass overrides close.

     * Cleanup should be via AltFinalizer calling close().

     */

    public static class StreamOverridesClose extends StreamOverrides {

        public StreamOverridesClose(String name) throws FileNotFoundException {

            super(name);

        }

        public void close() throws IOException {

            closeCounter.incrementAndGet();

            super.close();

        }

    }

    /**

     * Subclass overrides finalize.

     * Cleanup should be via the Cleaner (not close).

     */

    public static class StreamOverridesFinalize extends StreamOverrides {

        public StreamOverridesFinalize(String name) throws FileNotFoundException {

            super(name);

        }

        @SuppressWarnings({"deprecation","removal"})

        protected void finalize() throws IOException {

            super.finalize();

        }

    }

    /**

     * Subclass overrides finalize and close.

     * Cleanup should be via AltFinalizer calling close().

     */

    public static class StreamOverridesFinalizeClose extends StreamOverridesClose {

        public StreamOverridesFinalizeClose(String name) throws FileNotFoundException {

            super(name);

        }

        @SuppressWarnings({"deprecation","removal"})

        protected void finalize() throws IOException {

            super.finalize();

        }

    }

    /**

     * Main runs each test case and reports number of failures.

     */

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

        File inFile = new File(System.getProperty("test.dir", "."), FILE_NAME);

        inFile.createNewFile();

        inFile.deleteOnExit();

        String name = inFile.getPath();

        long fdCount0 = getFdCount();

        System.out.printf("initial count of open file descriptors: %d%n", fdCount0);

        int failCount = 0;

        failCount += test(new FileInputStream(name), CleanupType.CLEANER);

        failCount += test(new StreamOverrides(name), CleanupType.CLEANER);

        failCount += test(new StreamOverridesClose(name), CleanupType.CLOSE);

        failCount += test(new StreamOverridesFinalize(name), CleanupType.CLEANER);

        failCount += test(new StreamOverridesFinalizeClose(name), CleanupType.CLOSE);

        if (failCount > 0) {

            throw new AssertionError("Failed test count: " + failCount);

        }

        // Check the final count of open file descriptors

        long fdCount = getFdCount();

        System.out.printf("final count of open file descriptors: %d%n", fdCount);

        if (fdCount != fdCount0) {

            throw new AssertionError("raw fd count wrong: expected: " + fdCount0

                    + ", actual: " + fdCount);

        }

    }

    // Get the count of open file descriptors, or -1 if not available

    private static long getFdCount() {

        OperatingSystemMXBean mxBean = ManagementFactory.getOperatingSystemMXBean();

        return  (mxBean instanceof UnixOperatingSystemMXBean)

                ? ((UnixOperatingSystemMXBean) mxBean).getOpenFileDescriptorCount()

                : -1L;

    }

    private static int test(FileInputStream fis, CleanupType cleanType) throws Exception {

        try {

            System.out.printf("%nTesting %s%n", fis.getClass().getName());

            // Prepare to wait for FIS to be reclaimed

            ReferenceQueue<Object> queue = new ReferenceQueue<>();

            HashSet<Reference<?>> pending = new HashSet<>();

            WeakReference<FileInputStream> msWeak = new WeakReference<>(fis, queue);

            pending.add(msWeak);

            FileDescriptor fd = fis.getFD();

            WeakReference<FileDescriptor> fdWeak = new WeakReference<>(fd, queue);

            pending.add(fdWeak);

            Field fdField = FileDescriptor.class.getDeclaredField("fd");

            fdField.setAccessible(true);

            int ffd = fdField.getInt(fd);

            Field altFinalizerField = FileInputStream.class.getDeclaredField("altFinalizer");

            altFinalizerField.setAccessible(true);

            Object altFinalizer = altFinalizerField.get(fis);

            if ((altFinalizer != null) ^ (cleanType == CleanupType.CLOSE)) {

                throw new RuntimeException("Unexpected AltFinalizer: " + altFinalizer

                + ", for " + cleanType);

            }

            Field cleanupField = FileDescriptor.class.getDeclaredField("cleanup");

            cleanupField.setAccessible(true);

            Object cleanup = cleanupField.get(fd);

            System.out.printf("  cleanup: %s, alt: %s, ffd: %d, cf: %s%n",

                    cleanup, altFinalizer, ffd, cleanupField);

            if ((cleanup != null) ^ (cleanType == CleanupType.CLEANER)) {

                throw new Exception("unexpected cleanup: "

                + cleanup + ", for " + cleanType);

            }

            if (cleanup != null) {

                WeakReference<Object> cleanupWeak = new WeakReference<>(cleanup, queue);

                pending.add(cleanupWeak);

                System.out.printf("    fdWeak: %s%n    msWeak: %s%n    cleanupWeak: %s%n",

                        fdWeak, msWeak, cleanupWeak);

            }

            if (altFinalizer != null) {

                WeakReference<Object> altFinalizerWeak = new WeakReference<>(altFinalizer, queue);

                pending.add(altFinalizerWeak);

                System.out.printf("    fdWeak: %s%n    msWeak: %s%n    altFinalizerWeak: %s%n",

                        fdWeak, msWeak, altFinalizerWeak);

            }

            AtomicInteger closeCounter = fis instanceof StreamOverrides

                    ? ((StreamOverrides)fis).closeCounter() : null;

            Reference<?> r;

            while (((r = queue.remove(1000L)) != null)

                    || !pending.isEmpty()) {

                System.out.printf("    r: %s, pending: %d%n",

                        r, pending.size());

                if (r != null) {

                    pending.remove(r);

                } else {

                    fis = null;

                    fd = null;

                    cleanup = null;

                    altFinalizer = null;

                    System.gc();  // attempt to reclaim them

                }

            }

            Reference.reachabilityFence(fd);

            Reference.reachabilityFence(fis);

            Reference.reachabilityFence(cleanup);

            Reference.reachabilityFence(altFinalizer);

            // Confirm the correct number of calls to close depending on the cleanup type

            switch (cleanType) {

                case CLEANER:

                    if (closeCounter != null && closeCounter.get() > 0) {

                        throw new RuntimeException("Close should not have been called: count: "

                                + closeCounter);

                    }

                    break;

                case CLOSE:

                    if (closeCounter == null || closeCounter.get() == 0) {

                        throw new RuntimeException("Close should have been called: count: 0");

                    }

                    break;

            }

        } catch (Exception ex) {

            ex.printStackTrace(System.out);

            return 1;

        }

        return 0;

    }

}