/*

 * Copyright (c) 2013, 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.

 */

/**

 * @test

 * @library classes

 * @build test.Empty

 * @run main/othervm/timeout=200 FragmentMetaspaceSimple

 */

import java.io.DataInputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.util.ArrayList;

/**

 * Test that tries to fragment the native memory used by class loaders.

 * Keeps every other class loader alive in order to fragment the memory space

 * used to store classes and meta data. Since the memory is probably allocated in

 * chunks per class loader this will cause a lot of fragmentation if not handled

 * properly since every other chunk will be unused.

 */

public class FragmentMetaspaceSimple {

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

        runSimple(Long.valueOf(System.getProperty("time", "80000")));

        System.gc();

    }

    private static void runSimple(long time) {

        long startTime = System.currentTimeMillis();

        ArrayList<ClassLoader> cls = new ArrayList<>();

        char sep = File.separatorChar;

        String fileName = "classes" + sep + "test" + sep + "Empty.class";

        File file = new File(System.getProperty("test.classes",".") + sep + fileName);

        byte buff[] = read(file);

        int i = 0;

        for (i = 0; System.currentTimeMillis() < startTime + time; ++i) {

            ClassLoader ldr = new MyClassLoader(buff);

            if (i % 1000 == 0) {

                cls.clear();

            }

            // only keep every other class loader alive

            if (i % 2 == 1) {

                cls.add(ldr);

            }

            Class<?> c = null;

            try {

                c = ldr.loadClass("test.Empty");

                c.getClass().getClassLoader(); // make sure we have a valid class.

            } catch (ClassNotFoundException ex) {

                System.out.println("i=" + i + ", len" + buff.length);

                throw new RuntimeException(ex);

            }

            c = null;

        }

        cls = null;

        System.out.println("Finished " + i + " iterations in " +

                           (System.currentTimeMillis() - startTime) + " ms");

    }

    private static byte[] read(File file) {

        byte buff[] = new byte[(int)(file.length())];

        try {

            DataInputStream din = new DataInputStream(new FileInputStream(file));

            din.readFully(buff);

            din.close();

        } catch (IOException ex) {

            throw new RuntimeException(ex);

        }

        return buff;

    }

    static class MyClassLoader extends ClassLoader {

        byte buff[];

        MyClassLoader(byte buff[]) {

            this.buff = buff;

        }

        public Class<?> loadClass() throws ClassNotFoundException {

            String name = "test.Empty";

            try {

                return defineClass(name, buff, 0, buff.length);

            } catch (Throwable e) {

                throw new ClassNotFoundException(name, e);

            }

        }

    }

}