/*

 * Copyright (c) 2013, 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

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

 * questions.

 */

/*

 * @test

 *

 * @summary converted from VM Testbase metaspace/shrink_grow/ShrinkGrowTest.

 *

 * @library /vmTestbase /test/lib

 * @run driver jdk.test.lib.FileInstaller . .

 * @run main/othervm

 *      -XX:MetaspaceSize=10m

 *      -XX:MaxMetaspaceSize=20m

 *      -Xlog:gc*:gc.log

 *      metaspace.shrink_grow.ShrinkGrowTest.ShrinkGrowTest

 */

package metaspace.shrink_grow.ShrinkGrowTest;

import java.lang.reflect.InvocationHandler;

import java.lang.reflect.Method;

import java.lang.reflect.Proxy;

import java.lang.management.ManagementFactory;

import java.lang.management.MemoryPoolMXBean;

import java.net.URL;

import java.net.URLClassLoader;

import java.util.HashMap;

import java.util.Map;

/**

 * This is the main test in the metaspace shrink/grow series.

 *

 * It tries to allocate all available metespace (loads new classes and keeps

 * them in map), then checks that loading new classes causes OOM.

 * After that it does cleanup loaded classes and then expect the new classes

 * could be loaded again.

 *

 * <b>Note</b>: Don't forget to limit the metaspace size by giving

 * -XX:MaxMetaspaceSize=100k vm option.

 */

public class ShrinkGrowTest {

    /**

     * Dead classes storage.

     */

    private final Map<String, ShrinkGrowTest.Foo> loadedClasses = new HashMap<>();

    private static int counter = 0;

    private String errorMessage = "not completed";

     // thread id to distinguish threads in output

    private final String whoAmI;

    // the limit of classes to load expecting OOM

    private final int maxClassesToLoad;

    public static void main(String[] args) {

        String name = args.length > 0 ? args[0] : "singleTest" ;

        new ShrinkGrowTest(name, 20000).run();

    }

    /**

     * @param name - thread id used in logging

     * @param classesToLoad - the limit of classes to load expecting OOM

     */

    public ShrinkGrowTest(String name, int classesToLoad) {

        whoAmI = name;

        maxClassesToLoad = classesToLoad;

    }

    /**

     * Just outputs given message preceeded with the thread identifier

     *

     * @param message text to print out

     */

    void log(String message) {

        System.out.println("%" + whoAmI + "% " + message);

    }

    void throwFault(String message) {

        throw new TestFault("%" + whoAmI + "% " + message);

    }

    void throwFault(String message, Throwable t) {

        throw new TestFault("%" + whoAmI + "% " + message, t);

    }

    /**

     * Entry to the test.

     * Just exits if passes or throws an Error if failed.

     */

    public void run() {

        if (System.getProperty("requiresCompressedClassSpace") != null &&

                   !isCompressedClassSpaceAvailable()) {

                System.out.println("Not applicalbe, Compressed Class Space is required");

            return;

        }

        try {

            log("Bootstrapping string concatenation for " + whoAmI );

            go();

            // The quest completed! Yahoo!

            setErrorMessage(null);

            log("passed");

        } catch (TestFault failure) {

            failure.printStackTrace(System.err);

            setErrorMessage(failure.getMessage());

            log("failed :" + errorMessage);

            throw failure;

        } catch (Throwable badThing) {

            setErrorMessage(badThing.toString());

            throw new TestFault(badThing);

        }

    }

    private void go() {

        // step 1: eat all metaspace

        log("eating metaspace");

        runOutOfMetaspace(maxClassesToLoad);

        // step 2: try to load one more class

        // it should be impossible

        try {

            eatALittleMemory();

            throwFault("We haven't cleaned metaspace yet!");

        } catch (OutOfMemoryError error) {

            if (!isMetaspaceError(error)) {

                throwFault("Hmm, we ran out metaspace. Metaspace error is still excpected here " + error, error);

            }

        }

        // step 3: clean up metaspace and try loading a class again.

        log("washing hands before meal");

        loadedClasses.clear();

        System.gc();

        try {

            log("one more try to eat");

            eatALittleMemory();

        } catch (OutOfMemoryError error) {

            throwFault("we already should be able to consume metaspace " + error, error);

        }

    }

    /**

     * @return true if the test has successfully passed.

     */

    public boolean isPassed() {

        return errorMessage == null;

    }

    /**

     * @return message describing the reason of failure, or null if passes

     */

    public String getErrorMessage() {

        return errorMessage;

    }

    /**

     * Sets the message describing why test failed, or null if test passed

     */

    void setErrorMessage(String msg) {

        errorMessage = msg;

    }

    /**

     * Loads new classes until OOM.

     * Checks that OOM is caused by metaspace and throws an Error if not.

     *

     * @param times - maximum limit of classes to load.

     */

    private void runOutOfMetaspace(int times) {

        try {

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

                eatALittleMemory();

            }

        } catch (OutOfMemoryError error) {

            if (isMetaspaceError(error)) {

                return;

            }

            throwFault("We ran out of another space, not metaspace: " + error, error);

        }

        throwFault("OOM hasn't happened after " + times + " iterations. Might be too much space?..");

    }

    /**

     * Imitates class loading.

     * Each invocation of this method causes a new class loader object is created

     * and a new class is loaded by this class loader.

     * Method throws OOM when run out of memory.

     */

    private void eatALittleMemory() {

        try {

            String jarUrl = "file:" + counter + ".jar";

            counter++;

            URL[] urls = new URL[]{new URL(jarUrl)};

            URLClassLoader cl = new URLClassLoader(urls);

            ShrinkGrowTest.Foo foo = (ShrinkGrowTest.Foo) Proxy.newProxyInstance(cl,

                    new Class[]{ShrinkGrowTest.Foo.class},

                    new ShrinkGrowTest.FooInvocationHandler(new ShrinkGrowTest.FooBar()));

            loadedClasses.put(jarUrl, foo);

        } catch (java.net.MalformedURLException badThing) {

            // should never occur

            throwFault("Unexpeted error: " + badThing, badThing);

        }

    }

    /**

     * Checks if given OOM is about metaspace

     * @param error OOM

     * @return true if message contains 'metaspace' word, false otherwise.

     */

    boolean isMetaspaceError(OutOfMemoryError error) {

            String message = error.getMessage();

        return message != null && (message.contains("Metaspace") ||

                        message.contains("Compressed class space"));

    }

    boolean isCompressedClassSpaceAvailable() {

        for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {

            if (pool.getName().equalsIgnoreCase("Compressed class space")) {

                return true;

            }

        }

        return false;

    }

    /**

     * Runtime exception signaling test failure.

     */

    public static class TestFault extends RuntimeException {

        public TestFault(String message) {

            super(message);

        }

        public TestFault(Throwable t) {

            super(t);

        }

        public TestFault(String message, Throwable t) {

            super(message, t);

        }

    }

    public static interface Foo {

    }

    public static class FooBar implements ShrinkGrowTest.Foo {

    }

    class FooInvocationHandler implements InvocationHandler {

        private final ShrinkGrowTest.Foo foo;

        FooInvocationHandler(ShrinkGrowTest.Foo foo) {

            this.foo = foo;

        }

        @Override

        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

            return method.invoke(foo, args);

        }

    }

}