/*

 * Copyright (c) 2014, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import static com.oracle.java.testlibrary.Asserts.assertLessThanOrEqual;

import com.oracle.java.testlibrary.OutputAnalyzer;

import com.oracle.java.testlibrary.Platform;

import com.oracle.java.testlibrary.ProcessTools;

import com.oracle.java.testlibrary.Utils;

import java.io.IOException;

import java.lang.management.ManagementFactory;

import java.lang.management.MemoryUsage;

import java.text.DecimalFormat;

import java.text.DecimalFormatSymbols;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.LinkedList;

import java.util.List;

import sun.misc.Unsafe;

public class TestShrinkAuxiliaryData {

    private final static String[] initialOpts = new String[]{

        "-XX:MinHeapFreeRatio=10",

        "-XX:MaxHeapFreeRatio=11",

        "-XX:+UseG1GC",

        "-XX:G1HeapRegionSize=1m",

        "-XX:-ExplicitGCInvokesConcurrent",

        "-XX:+PrintGCDetails"

    };

    private final int RSetCacheSize;

    protected TestShrinkAuxiliaryData(int RSetCacheSize) {

        this.RSetCacheSize = RSetCacheSize;

    }

    protected void test() throws Exception {

        ArrayList<String> vmOpts = new ArrayList();

        Collections.addAll(vmOpts, initialOpts);

        int maxCacheSize = Math.max(0, Math.min(31, getMaxCacheSize()));

        if (maxCacheSize < RSetCacheSize) {

            System.out.format("Skiping test for %d cache size due max cache size %d",

                    RSetCacheSize, maxCacheSize

            );

            return;

        }

        printTestInfo(maxCacheSize);

        vmOpts.add("-XX:G1ConcRSLogCacheSize=" + RSetCacheSize);

        vmOpts.addAll(Arrays.asList(Utils.getTestJavaOpts()));

        // for 32 bits ObjectAlignmentInBytes is not a option

        if (Platform.is32bit()) {

            ArrayList<String> vmOptsWithoutAlign = new ArrayList(vmOpts);

            vmOptsWithoutAlign.add(ShrinkAuxiliaryDataTest.class.getName());

            performTest(vmOptsWithoutAlign);

            return;

        }

        for (int alignment = 3; alignment <= 8; alignment++) {

            ArrayList<String> vmOptsWithAlign = new ArrayList(vmOpts);

            vmOptsWithAlign.add("-XX:ObjectAlignmentInBytes="

                    + (int) Math.pow(2, alignment));

            vmOptsWithAlign.add(ShrinkAuxiliaryDataTest.class.getName());

            performTest(vmOptsWithAlign);

        }

    }

    private void performTest(List<String> opts) throws Exception {

        ProcessBuilder pb

                       = ProcessTools.createJavaProcessBuilder(

                opts.toArray(new String[opts.size()])

        );

        OutputAnalyzer output = new OutputAnalyzer(pb.start());

        output.shouldHaveExitValue(0);

    }

    private void printTestInfo(int maxCacheSize) {

        DecimalFormat grouped = new DecimalFormat("000,000");

        DecimalFormatSymbols formatSymbols = grouped.getDecimalFormatSymbols();

        formatSymbols.setGroupingSeparator(' ');

        grouped.setDecimalFormatSymbols(formatSymbols);

        System.out.format("Test will use %s bytes of memory of %s available%n"

                + "Available memory is %s with %d bytes pointer size - can save %s pointers%n"

                + "Max cache size: 2^%d = %s elements%n",

                grouped.format(ShrinkAuxiliaryDataTest.getMemoryUsedByTest()),

                grouped.format(Runtime.getRuntime().freeMemory()),

                grouped.format(Runtime.getRuntime().freeMemory()

                        - ShrinkAuxiliaryDataTest.getMemoryUsedByTest()),

                Unsafe.ADDRESS_SIZE,

                grouped.format((Runtime.getRuntime().freeMemory()

                        - ShrinkAuxiliaryDataTest.getMemoryUsedByTest())

                        / Unsafe.ADDRESS_SIZE),

                maxCacheSize,

                grouped.format((int) Math.pow(2, maxCacheSize))

        );

    }

    /**

     * Detects maximum possible size of G1ConcRSLogCacheSize available for

     * current process based on maximum available process memory size

     *

     * @return power of two

     */

    private static int getMaxCacheSize() {

        long availableMemory = Runtime.getRuntime().freeMemory()

                - ShrinkAuxiliaryDataTest.getMemoryUsedByTest() - 1l;

        if (availableMemory <= 0) {

            return 0;

        }

        long availablePointersCount = availableMemory / Unsafe.ADDRESS_SIZE;

        return (63 - (int) Long.numberOfLeadingZeros(availablePointersCount));

    }

    static class ShrinkAuxiliaryDataTest {

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

            int iterateCount = DEFAULT_ITERATION_COUNT;

            if (args.length > 0) {

                try {

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

                } catch (NumberFormatException e) {

                    //num_iterate remains default

                }

            }

            new ShrinkAuxiliaryDataTest().test(iterateCount);

        }

        class GarbageObject {

            private final List<byte[]> payload = new ArrayList();

            private final List<GarbageObject> ref = new LinkedList();

            public GarbageObject(int size) {

                payload.add(new byte[size]);

            }

            public void addRef(GarbageObject g) {

                ref.add(g);

            }

            public void mutate() {

                if (!payload.isEmpty() && payload.get(0).length > 0) {

                    payload.get(0)[0] = (byte) (Math.random() * Byte.MAX_VALUE);

                }

            }

        }

        private final List<GarbageObject> garbage = new ArrayList();

        public void test(int num_iterate) throws IOException {

            allocate();

            link();

            mutate();

            deallocate();

            MemoryUsage muBeforeHeap

                        = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();

            MemoryUsage muBeforeNonHeap

                        = ManagementFactory.getMemoryMXBean().getNonHeapMemoryUsage();

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

                allocate();

                link();

                mutate();

                deallocate();

            }

            System.gc();

            MemoryUsage muAfterHeap

                        = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();

            MemoryUsage muAfterNonHeap

                        = ManagementFactory.getMemoryMXBean().getNonHeapMemoryUsage();

            assertLessThanOrEqual(muAfterHeap.getCommitted(), muBeforeHeap.getCommitted(),

                    String.format("heap decommit failed - after > before: %d > %d",

                            muAfterHeap.getCommitted(), muBeforeHeap.getCommitted()

                    )

            );

            if (muAfterHeap.getCommitted() < muBeforeHeap.getCommitted()) {

                assertLessThanOrEqual(muAfterNonHeap.getCommitted(), muBeforeNonHeap.getCommitted(),

                        String.format("non-heap decommit failed - after > before: %d > %d",

                                muAfterNonHeap.getCommitted(), muBeforeNonHeap.getCommitted()

                        )

                );

            }

        }

        private void allocate() {

            for (int r = 0; r < REGIONS_TO_ALLOCATE; r++) {

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

                    GarbageObject g = new GarbageObject(REGION_SIZE

                            / NUM_OBJECTS_PER_REGION);

                    garbage.add(g);

                }

            }

        }

        /**

         * Iterate through all allocated objects, and link to objects in another

         * regions

         */

        private void link() {

            for (int ig = 0; ig < garbage.size(); ig++) {

                int regionNumber = ig / NUM_OBJECTS_PER_REGION;

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

                    int regionToLink;

                    do {

                        regionToLink = (int) (Math.random()

                                * REGIONS_TO_ALLOCATE);

                    } while (regionToLink == regionNumber);

                    // get random garbage object from random region

                    garbage.get(ig).addRef(garbage.get(regionToLink

                            * NUM_OBJECTS_PER_REGION + (int) (Math.random()

                            * NUM_OBJECTS_PER_REGION)));

                }

            }

        }

        private void mutate() {

            for (int ig = 0; ig < garbage.size(); ig++) {

                garbage.get(ig).mutate();

            }

        }

        private void deallocate() {

            garbage.clear();

            System.gc();

        }

        static long getMemoryUsedByTest() {

            return REGIONS_TO_ALLOCATE * REGION_SIZE;

        }

        private static final int REGION_SIZE = 1024 * 1024;

        private static final int DEFAULT_ITERATION_COUNT = 1;   // iterate main scenario

        private static final int REGIONS_TO_ALLOCATE = 5;

        private static final int NUM_OBJECTS_PER_REGION = 10;

        private static final int NUM_LINKS = 20; // how many links create for each object

    }

}