/*
 * Copyright [2020-2030] [https://www.stylefeng.cn]
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Guns采用APACHE LICENSE 2.0开源协议，您在使用过程中，需要注意以下几点：
 *
 * 1.请不要删除和修改根目录下的LICENSE文件。
 * 2.请不要删除和修改Guns源码头部的版权声明。
 * 3.请保留源码和相关描述文件的项目出处，作者声明等。
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 * 5.在修改包名，模块名称，项目代码等时，请注明软件出处 https://gitee.com/stylefeng/guns
 * 6.若您的项目无法满足以上几点，可申请商业授权
 */
package cn.stylefeng.roses.kernel.rule.util;

import lombok.extern.slf4j.Slf4j;
import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopProxy;
import org.springframework.aop.support.AopUtils;

import java.lang.reflect.Field;

/**
 * 获取代理原始对象的工具
 *
 * @author fengshuonan
 * @since 2020/10/19 16:20
 */
@Slf4j
public class AopTargetUtils {

    /**
     * 获取代理对象的原始对象
     *
     * @author fengshuonan
     * @since 2020/10/19 16:21
     */
    public static Object getTarget(Object proxy) {

        // 不是代理对象，直接返回参数对象
        if (!AopUtils.isAopProxy(proxy)) {
            return proxy;
        }

        // 判断是否是jdk还是cglib代理的对象
        try {
            if (AopUtils.isJdkDynamicProxy(proxy)) {
                return getJdkDynamicProxyTargetObject(proxy);
            } else {
                return getCglibProxyTargetObject(proxy);
            }
        } catch (Exception e) {
            log.error("获取代理对象异常", e);
            return null;
        }
    }

    /**
     * 获取cglib代理的对象
     *
     * @author fengshuonan
     * @since 2020/10/19 16:21
     */
    private static Object getCglibProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");
        h.setAccessible(true);
        Object dynamicAdvisedInterceptor = h.get(proxy);
        Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
        advised.setAccessible(true);
        return ((AdvisedSupport) advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();
    }

    /**
     * 获取jdk代理的对象
     *
     * @author fengshuonan
     * @since 2020/10/19 16:22
     */
    private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getSuperclass().getDeclaredField("h");
        h.setAccessible(true);
        AopProxy aopProxy = (AopProxy) h.get(proxy);
        Field advised = aopProxy.getClass().getDeclaredField("advised");
        advised.setAccessible(true);
        return ((AdvisedSupport) advised.get(aopProxy)).getTargetSource().getTarget();
    }

}  