/*

 * 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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 jdk.jfr.internal.instrument;

import java.lang.reflect.Method;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

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

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

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

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

import jdk.internal.org.objectweb.asm.commons.RemappingMethodAdapter;

import jdk.internal.org.objectweb.asm.commons.SimpleRemapper;

import jdk.internal.org.objectweb.asm.tree.ClassNode;

import jdk.internal.org.objectweb.asm.tree.MethodNode;

import jdk.jfr.internal.LogLevel;

import jdk.jfr.internal.LogTag;

import jdk.jfr.internal.Logger;

/**

 * This class will merge (some) methods from one class into another one.

 *

 * @author Staffan Larsen

 */

@Deprecated

final class JIMethodMergeAdapter extends ClassVisitor {

    private final ClassNode cn;

    private final List<Method> methodFilter;

    private final Map<String, String> typeMap;

    /**

     * Methods in methodFilter that exist in cn will be merged into cv. If the method already exists,

     * the original method will be deleted.

     *

     * @param cv

     * @param cn - a ClassNode with Methods that will be merged into this class

     * @param methodFilter - only methods in this list will be merged

     * @param typeMappings - while merging, type references in the methods will be changed according to this map

     */

    public JIMethodMergeAdapter(ClassVisitor cv, ClassNode cn, List<Method> methodFilter, JITypeMapping[] typeMappings) {

        super(Opcodes.ASM5, cv);

        this.cn = cn;

        this.methodFilter = methodFilter;

        this.typeMap = new HashMap<>();

        for (JITypeMapping tm : typeMappings) {

            typeMap.put(tm.from().replace('.', '/'), tm.to().replace('.', '/'));

        }

    }

    @Override

    public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {

        super.visit(version, access, name, signature, superName, interfaces);

        typeMap.put(cn.name, name);

    }

    @Override

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

        if(methodInFilter(name, desc)) {

            // If the method is one that we will be replacing, delete the method

            Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Deleting " + name + desc);

            return null;

        }

        return super.visitMethod(access, name, desc, signature, exceptions);

    }

    @Override

    public void visitEnd() {

        SimpleRemapper remapper = new SimpleRemapper(typeMap);

        for (MethodNode mn : cn.methods) {

            // Check if the method is in the list of methods to copy

            if (methodInFilter(mn.name, mn.desc)) {

                Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Copying method: " + mn.name + mn.desc);

                Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG,  "   with mapper: " + typeMap);

                String[] exceptions = new String[mn.exceptions.size()];

                mn.exceptions.toArray(exceptions);

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

                mn.instructions.resetLabels();

                mn.accept(new RemappingMethodAdapter(mn.access, mn.desc, mv, remapper));

            }

        }

        super.visitEnd();

    }

    private boolean methodInFilter(String name, String desc) {

        for(Method m : methodFilter) {

            if (m.getName().equals(name) && Type.getMethodDescriptor(m).equals(desc)) {

                return true;

            }

        }

        return false;

    }

}