/*

 * 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

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 */

import java.io.File;

import java.io.IOException;

import java.io.RandomAccessFile;

import java.lang.ref.Reference;

import java.lang.ref.WeakReference;

import java.nio.channels.FileLock;

import java.nio.channels.OverlappingFileLockException;

import java.nio.file.Files;

import java.nio.file.Path;

import jdk.test.lib.util.FileUtils;

/*

 * @test

 * @bug 8166253

 * @summary Verify that OverlappingFileLockException is thrown when expected.

 * @library .. /test/lib

 * @build jdk.test.lib.util.FileUtils

 * @run main/othervm FileLockGC

 */

public class FileLockGC {

    public enum TestType {

        NO_GC_NO_RELEASE(true),

        // A hypothetical 'GC_THEN_RELEASE' case is infeasible

        RELEASE(false),

        RELEASE_THEN_GC(false),

        GC(true);

        private final boolean exceptionExpected;

        TestType(boolean exceptionExpected) {

            this.exceptionExpected = exceptionExpected;

        }

        boolean exceptionExpected() {

            return exceptionExpected;

        }

    }

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

        final File f = new File(System.getProperty("test.dir", ".")

            + File.separator + "junk.txt");

        final Path p = f.toPath();

        int failures = 0;

        for (TestType t : TestType.values()) {

            try {

                if (!testFileLockGC(f, t)) {

                    failures++;

                }

            } finally {

                FileUtils.deleteFileIfExistsWithRetry(p);

            }

        }

        if (failures != 0) {

            throw new RuntimeException("Test had " + failures + " failure(s)");

        }

    }

    private static boolean testFileLockGC(File f, TestType type)

        throws InterruptedException, IOException {

        System.out.printf("Test %s starting%n", type.toString());

        final RandomAccessFile raf1 = new RandomAccessFile(f, "rw");

        FileLock lock1 = raf1.getChannel().tryLock();

        WeakReference<FileLock> ref1 = new WeakReference(lock1);

        switch (type) {

            case GC:

                lock1 = null;

                System.gc();

                break;

            case RELEASE:

                lock1.release();

                break;

            case RELEASE_THEN_GC:

                lock1.release();

                lock1 = null;

                System.gc();

                break;

            default: // NO_GC_NO_RELEASE

                // lock1 is neither collected nor released

                break;

        }

        final RandomAccessFile raf2 = new RandomAccessFile(f, "rw");

        boolean success = true;

        FileLock lock2 = null;

        try {

            lock2 = raf2.getChannel().tryLock();

            if (type.exceptionExpected()) {

                System.err.printf

                    ("No expected OverlappingFileLockException for test %s%n",

                    type.toString());

                success = false;

            }

        } catch (OverlappingFileLockException ofe) {

            if (!type.exceptionExpected()) {

                System.err.printf

                    ("Unexpected OverlappingFileLockException for test %s%n",

                    type.toString());

                success = false;

            }

        } finally {

            if (lock1 != null) {

                lock1.release();

            }

            if (lock2 != null) {

                lock2.release();

            }

            raf2.close();

            raf1.close();

            System.out.printf("Test %s finished%n", type.toString());

        }

        return success;

    }

}