/*

 * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.

 *

 * 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 TestStringDedup

 * @summary Test Shenandoah string deduplication implementation

 * @key gc

 * @requires vm.gc.Shenandoah & !vm.graal.enabled

 * @library /test/lib

 * @modules java.base/jdk.internal.misc:open

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

 *          java.management

 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCMode=passive            -XX:+ShenandoahDegeneratedGC -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCMode=passive            -XX:-ShenandoahDegeneratedGC -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

 *

 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive   -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

 *

 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC                                         -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCMode=traversal          -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

 *

 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=compact      -XX:+UseStringDeduplication -Xmx256M -Xlog:gc+stats TestStringDedup

 */

import java.lang.reflect.*;

import java.util.*;

import sun.misc.*;

public class TestStringDedup {

    private static Field valueField;

    private static Unsafe unsafe;

    private static final int UniqueStrings = 20;

    static {

        try {

            Field field = Unsafe.class.getDeclaredField("theUnsafe");

            field.setAccessible(true);

            unsafe = (Unsafe) field.get(null);

            valueField = String.class.getDeclaredField("value");

            valueField.setAccessible(true);

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

    private static Object getValue(String string) {

        try {

            return valueField.get(string);

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

    static class StringAndId {

        private String str;

        private int id;

        public StringAndId(String str, int id) {

            this.str = str;

            this.id = id;

        }

        public String str() {

            return str;

        }

        public int id() {

            return id;

        }

    }

    private static void generateStrings(ArrayList<StringAndId> strs, int unique_strs) {

        Random rn = new Random();

        for (int u = 0; u < unique_strs; u++) {

            int n = rn.nextInt() % 10;

            n = Math.max(n, 2);

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

                strs.add(new StringAndId("Unique String " + u, u));

            }

        }

    }

    private static int verifyDedepString(ArrayList<StringAndId> strs) {

        HashMap<Object, StringAndId> seen = new HashMap<>();

        int total = 0;

        int dedup = 0;

        for (StringAndId item : strs) {

            total++;

            StringAndId existing_item = seen.get(getValue(item.str()));

            if (existing_item == null) {

                seen.put(getValue(item.str()), item);

            } else {

                if (item.id() != existing_item.id() ||

                        !item.str().equals(existing_item.str())) {

                    System.out.println("StringDedup error:");

                    System.out.println("String: " + item.str() + " != " + existing_item.str());

                    throw new RuntimeException("StringDedup Test failed");

                } else {

                    dedup++;

                }

            }

        }

        System.out.println("Dedup: " + dedup + "/" + total + " unique: " + (total - dedup));

        return (total - dedup);

    }

    public static void main(String[] args) {

        ArrayList<StringAndId> astrs = new ArrayList<>();

        generateStrings(astrs, UniqueStrings);

        System.gc();

        System.gc();

        System.gc();

        System.gc();

        System.gc();

        if (verifyDedepString(astrs) != UniqueStrings) {

            // Can not guarantee all strings are deduplicated, there can

            // still have pending items in queues.

            System.out.println("Not all strings are deduplicated");

        }

    }

}