/*

 * Copyright (c) 2016, 2017, 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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 */

/*

 * @test HandshakeWalkStackTest

 * @library /testlibrary /test/lib

 * @build HandshakeWalkStackTest

 * @run driver ClassFileInstaller sun.hotspot.WhiteBox

 *                              sun.hotspot.WhiteBox$WhiteBoxPermission

 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI HandshakeWalkStackTest

 */

import jdk.test.lib.Asserts;

import sun.hotspot.WhiteBox;

public class HandshakeWalkStackTest {

    public static void main(String... args) throws Exception {

        int iterations = 3;

        if (args.length > 0) {

            iterations = Integer.parseInt(args[0]);

        }

        test(iterations);

    }

    private static void test(int iterations) throws Exception {

        Thread loop_thread  = new Thread(() -> run_loop(create_list()));

        Thread alloc_thread = new Thread(() -> run_alloc());

        Thread wait_thread  = new Thread(() -> run_wait(new Object() {}));

        loop_thread.start();

        alloc_thread.start();

        wait_thread.start();

        WhiteBox wb = WhiteBox.getWhiteBox();

        int walked = 0;

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

            System.out.println("Iteration " + i);

            System.out.flush();

            Thread.sleep(200);

            walked = wb.handshakeWalkStack(loop_thread, false);

            Asserts.assertEQ(walked, 1, "Must have walked one thread stack");

            Thread.sleep(200);

            walked = wb.handshakeWalkStack(alloc_thread, false);

            Asserts.assertEQ(walked, 1, "Must have walked one thread stack");

            Thread.sleep(200);

            walked = wb.handshakeWalkStack(wait_thread, false);

            Asserts.assertEQ(walked, 1, "Must have walked one thread stack");

            Thread.sleep(200);

            walked = wb.handshakeWalkStack(Thread.currentThread(), false);

            Asserts.assertEQ(walked, 1, "Must have walked one thread stack");

        }

        Thread.sleep(200);

        walked = wb.handshakeWalkStack(null, true);

        Asserts.assertGT(walked, 4, "Must have walked more than three thread stacks");

    }

    static class List {

        List next;

        List(List next) {

            this.next = next;

        }

    }

    public static List create_list() {

        List head = new List(null);

        List elem = new List(head);

        List elem2 = new List(elem);

        List elem3 = new List(elem2);

        List elem4 = new List(elem3);

        head.next = elem4;

        return head;

    }

    public static void run_loop(List loop) {

        while (loop.next != null) {

            loop = loop.next;

        }

    }

    public static byte[] array;

    public static void run_alloc() {

        while (true) {

            // Write to public static to ensure the byte array escapes.

            array = new byte[4096];

        }

    }

    public static void run_wait(Object lock) {

        synchronized (lock) {

            try {

                lock.wait();

            } catch (InterruptedException ie) {}

        }

    }

}