/*

 * 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.

 */

/**

 * @test

 * @bug 8058828

 * @run main/bootclasspath -Xbatch VMAnonymousClasses

 */

import jdk.internal.org.objectweb.asm.ClassWriter;

import jdk.internal.org.objectweb.asm.MethodVisitor;

import jdk.internal.org.objectweb.asm.Opcodes;

import sun.misc.Unsafe;

import java.lang.invoke.ConstantCallSite;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodType;

import java.lang.invoke.MutableCallSite;

import java.lang.invoke.VolatileCallSite;

public class VMAnonymousClasses {

    static final String TEST_METHOD_NAME = "constant";

    static final Unsafe UNSAFE = Unsafe.getUnsafe();

    static int getConstantPoolSize(byte[] classFile) {

        // The first few bytes:

        // u4 magic;

        // u2 minor_version;

        // u2 major_version;

        // u2 constant_pool_count;

        return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);

    }

    static void test(Object value) throws ReflectiveOperationException {

        System.out.printf("Test: %s", value != null ? value.getClass() : "null");

        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);

        cw.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC | Opcodes.ACC_SUPER, "Test", null, "java/lang/Object", null);

        MethodVisitor mv = cw.visitMethod(Opcodes.ACC_STATIC | Opcodes.ACC_PUBLIC, TEST_METHOD_NAME, "()Ljava/lang/Object;", null, null);

        String placeholder = "CONSTANT";

        int index = cw.newConst(placeholder);

        mv.visitLdcInsn(placeholder);

        mv.visitInsn(Opcodes.ARETURN);

        mv.visitMaxs(0, 0);

        mv.visitEnd();

        byte[] classFile = cw.toByteArray();

        Object[] cpPatches = new Object[getConstantPoolSize(classFile)];

        cpPatches[index] = value;

        Class<?> test = UNSAFE.defineAnonymousClass(VMAnonymousClasses.class, classFile, cpPatches);

        Object expectedResult = (value != null) ? value : placeholder;

        for (int i = 0; i<15000; i++) {

            Object result = test.getMethod(TEST_METHOD_NAME).invoke(null);

            if (result != expectedResult) {

                throw new AssertionError(String.format("Wrong value returned: %s != %s", value, result));

            }

        }

        System.out.println(" PASSED");

    }

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

        // Objects

        test(new Object());

        test("TEST");

        test(new VMAnonymousClasses());

        test(null);

        // Class

        test(String.class);

        // Arrays

        test(new boolean[0]);

        test(new byte[0]);

        test(new char[0]);

        test(new short[0]);

        test(new int[0]);

        test(new long[0]);

        test(new float[0]);

        test(new double[0]);

        test(new Object[0]);

        // Multi-dimensional arrays

        test(new byte[0][0]);

        test(new Object[0][0]);

        // MethodHandle-related

        MethodType   mt = MethodType.methodType(void.class, String[].class);

        MethodHandle mh = MethodHandles.lookup().findStatic(VMAnonymousClasses.class, "main", mt);

        test(mt);

        test(mh);

        test(new ConstantCallSite(mh));

        test(new MutableCallSite(MethodType.methodType(void.class)));

        test(new VolatileCallSite(MethodType.methodType(void.class)));

        System.out.println("TEST PASSED");

    }

}