/*

 * 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 8042235

 * @summary redefining method used by multiple MethodHandles crashes VM

 * @compile -XDignore.symbol.file RedefineMethodUsedByMultipleMethodHandles.java

 * @run main RedefineMethodUsedByMultipleMethodHandles

 */

import java.io.*;

import java.lang.instrument.*;

import java.lang.invoke.*;

import java.lang.invoke.MethodHandles.Lookup;

import java.lang.management.*;

import java.lang.reflect.*;

import java.nio.file.*;

import java.security.*;

import java.util.jar.*;

import javax.tools.*;

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

public class RedefineMethodUsedByMultipleMethodHandles {

    static class Foo {

        public static Object getName() {

            return "foo";

        }

    }

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

        Lookup lookup = MethodHandles.lookup();

        Method fooMethod = Foo.class.getDeclaredMethod("getName");

        // fooMH2 displaces fooMH1 from the MemberNamesTable

        MethodHandle fooMH1 = lookup.unreflect(fooMethod);

        MethodHandle fooMH2 = lookup.unreflect(fooMethod);

        System.out.println("fooMH1.invoke = " + fooMH1.invokeExact());

        System.out.println("fooMH2.invoke = " + fooMH2.invokeExact());

        // Redefining Foo.getName() causes vmtarget to be updated

        // in fooMH2 but not fooMH1

        redefineFoo();

        // Full GC causes fooMH1.vmtarget to be deallocated

        System.gc();

        // Calling fooMH1.vmtarget crashes the VM

        System.out.println("fooMH1.invoke = " + fooMH1.invokeExact());

    }

    /**

     * Adds the class file bytes for {@code c} to {@code jar}.

     */

    static void add(JarOutputStream jar, Class<?> c) throws IOException {

        String classAsPath = c.getName().replace('.', '/') + ".class";

        jar.putNextEntry(new JarEntry(classAsPath));

        InputStream stream = c.getClassLoader().getResourceAsStream(classAsPath);

        int b;

        while ((b = stream.read()) != -1) {

            jar.write(b);

        }

    }

    static void redefineFoo() throws Exception {

        Manifest manifest = new Manifest();

        manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");

        Attributes mainAttrs = manifest.getMainAttributes();

        mainAttrs.putValue("Agent-Class", FooAgent.class.getName());

        mainAttrs.putValue("Can-Redefine-Classes", "true");

        mainAttrs.putValue("Can-Retransform-Classes", "true");

        Path jar = Files.createTempFile("myagent", ".jar");

        try {

            JarOutputStream jarStream = new JarOutputStream(new FileOutputStream(jar.toFile()), manifest);

            add(jarStream, FooAgent.class);

            add(jarStream, FooTransformer.class);

            jarStream.close();

            runAgent(jar);

        } finally {

            Files.deleteIfExists(jar);

        }

    }

    public static void runAgent(Path agent) throws Exception {

        String vmName = ManagementFactory.getRuntimeMXBean().getName();

        int p = vmName.indexOf('@');

        assert p != -1 : "VM name not in <pid>@<host> format: " + vmName;

        String pid = vmName.substring(0, p);

        ClassLoader cl = ToolProvider.getSystemToolClassLoader();

        Class<?> c = Class.forName("com.sun.tools.attach.VirtualMachine", true, cl);

        Method attach = c.getDeclaredMethod("attach", String.class);

        Method loadAgent = c.getDeclaredMethod("loadAgent", String.class);

        Method detach = c.getDeclaredMethod("detach");

        Object vm = attach.invoke(null, pid);

        loadAgent.invoke(vm, agent.toString());

        detach.invoke(vm);

    }

    public static class FooAgent {

        public static void agentmain(@SuppressWarnings("unused") String args, Instrumentation inst) throws Exception {

            assert inst.isRedefineClassesSupported();

            assert inst.isRetransformClassesSupported();

            inst.addTransformer(new FooTransformer(), true);

            Class<?>[] classes = inst.getAllLoadedClasses();

            for (int i = 0; i < classes.length; i++) {

                Class<?> c = classes[i];

                if (c == Foo.class) {

                    inst.retransformClasses(new Class[]{c});

                }

            }

        }

    }

    static class FooTransformer implements ClassFileTransformer {

        @Override

        public byte[] transform(ClassLoader cl, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {

            if (Foo.class.equals(classBeingRedefined)) {

                System.out.println("redefining " + classBeingRedefined);

                ClassReader cr = new ClassReader(classfileBuffer);

                ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_FRAMES);

                ClassVisitor adapter = new ClassVisitor(Opcodes.ASM5, cw) {

                    @Override

                    public MethodVisitor visitMethod(int access, String base, String desc, String signature, String[] exceptions) {

                        MethodVisitor mv = cv.visitMethod(access, base, desc, signature, exceptions);

                        if (mv != null) {

                            mv = new MethodVisitor(Opcodes.ASM5, mv) {

                                @Override

                                public void visitLdcInsn(Object cst) {

                                    System.out.println("replacing \"" + cst + "\" with \"bar\"");

                                    mv.visitLdcInsn("bar");

                                }

                            };

                        }

                        return mv;

                    }

                };

                cr.accept(adapter, ClassReader.SKIP_FRAMES);

                cw.visitEnd();

                return cw.toByteArray();

            }

            return classfileBuffer;

        }

    }

}