/*

 * Copyright (c) 2018, 2019, 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

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 */

package org.graalvm.compiler.core.test;

import java.lang.invoke.MethodHandles;

import java.lang.reflect.Method;

import java.security.ProtectionDomain;

import org.graalvm.compiler.serviceprovider.JavaVersionUtil;

import org.objectweb.asm.Opcodes;

import sun.misc.Unsafe;

public abstract class CustomizedBytecodePatternTest extends GraalCompilerTest implements Opcodes {

    protected Class<?> getClass(String className) throws ClassNotFoundException {

        return new CachedLoader(CustomizedBytecodePatternTest.class.getClassLoader(), className).findClass(className);

    }

    /**

     * @param className

     * @param lookUp lookup object with boot class load capability (required for jdk 9 and above)

     * @return loaded class

     * @throws ClassNotFoundException

     */

    protected Class<?> getClassBL(String className, MethodHandles.Lookup lookUp) throws ClassNotFoundException {

        byte[] gen = generateClass(className.replace('.', '/'));

        Method defineClass = null;

        Class<?> loadedClass = null;

        try {

            if (JavaVersionUtil.JAVA_SPEC <= 8) {

                defineClass = Unsafe.class.getDeclaredMethod("defineClass", String.class, byte[].class, int.class, int.class, ClassLoader.class, ProtectionDomain.class);

                loadedClass = (Class<?>) defineClass.invoke(UNSAFE, className, gen, 0, gen.length, null, null);

            } else {

                defineClass = MethodHandles.lookup().getClass().getDeclaredMethod("defineClass", byte[].class);

                loadedClass = (Class<?>) defineClass.invoke(lookUp, gen);

            }

        } catch (Exception e) {

            throw new ClassNotFoundException(className, e);

        }

        return loadedClass;

    }

    private class CachedLoader extends ClassLoader {

        final String className;

        Class<?> loaded;

        CachedLoader(ClassLoader parent, String className) {

            super(parent);

            this.className = className;

        }

        @Override

        protected Class<?> findClass(String name) throws ClassNotFoundException {

            if (name.equals(className)) {

                if (loaded == null) {

                    byte[] gen = generateClass(name.replace('.', '/'));

                    loaded = defineClass(name, gen, 0, gen.length);

                }

                return loaded;

            } else {

                return super.findClass(name);

            }

        }

    }

    protected abstract byte[] generateClass(String internalClassName);

}