scouter.agent.asm.asyncsupport.RequestStartAsyncASM.java Source code

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Here is the source code for scouter.agent.asm.asyncsupport.RequestStartAsyncASM.java

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/*
 *  Copyright 2015 the original author or authors.
 *  @https://github.com/scouter-project/scouter
 *
 *  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.
 */
package scouter.agent.asm.asyncsupport;

import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.LocalVariablesSorter;
import scouter.agent.ClassDesc;
import scouter.agent.Configure;
import scouter.agent.asm.IASM;
import scouter.agent.asm.util.AsmUtil;
import scouter.agent.asm.util.HookingSet;
import scouter.agent.trace.TraceMain;

import java.util.ArrayList;
import java.util.List;

/**
 * @author Gun Lee (gunlee01@gmail.com) on 2017. 2. 21.
 */
public class RequestStartAsyncASM implements IASM, Opcodes {
    private static List<String> preservedAsyncServletStartPatterns = new ArrayList<String>();
    static {
        preservedAsyncServletStartPatterns.add(
                "org.apache.catalina.connector.Request.startAsync(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)Ljavax/servlet/AsyncContext;");
    }

    private Configure conf = Configure.getInstance();
    private List<HookingSet> startTarget;

    public RequestStartAsyncASM() {
        startTarget = HookingSet.getHookingMethodSet(HookingSet
                .buildPatterns(conf.hook_async_servlet_start_patterns, preservedAsyncServletStartPatterns));
    }

    public ClassVisitor transform(ClassVisitor cv, String className, ClassDesc classDesc) {
        if (conf.hook_async_servlet_enabled == false) {
            return cv;
        }

        for (int i = 0; i < startTarget.size(); i++) {
            HookingSet mset = startTarget.get(i);
            if (mset.classMatch.include(className)) {
                return new RequestCV(cv, mset, className);
            }
        }

        return cv;
    }
}

class RequestCV extends ClassVisitor implements Opcodes {
    String className;
    HookingSet mset;

    public RequestCV(ClassVisitor cv, HookingSet mset, String className) {
        super(ASM7, cv);
        this.mset = mset;
        this.className = className;
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
        if (mv == null || mset.isA(name, desc) == false) {
            return mv;
        }
        if (AsmUtil.isSpecial(name)) {
            return mv;
        }

        return new StartAsyncMV(access, desc, mv);
    }
}

class StartAsyncMV extends LocalVariablesSorter implements Opcodes {
    private static final String TRACEMAIN = TraceMain.class.getName().replace('.', '/');
    private static final String END_METHOD = "endRequestAsyncStart";
    private static final String END_SIGNATURE = "(Ljava/lang/Object;)V";

    private Type returnType;

    public StartAsyncMV(int access, String desc, MethodVisitor mv) {
        super(ASM7, access, desc, mv);
        returnType = Type.getReturnType(desc);
    }

    @Override
    public void visitInsn(int opcode) {
        if ((opcode >= IRETURN && opcode <= RETURN)) {
            Type tp = returnType;
            if (!"javax/servlet/AsyncContext".equals(tp.getInternalName())) {
                return;
            }
            int i = newLocal(tp);
            mv.visitVarInsn(Opcodes.ASTORE, i);
            mv.visitVarInsn(Opcodes.ALOAD, i);
            mv.visitVarInsn(Opcodes.ALOAD, i);

            mv.visitMethodInsn(Opcodes.INVOKESTATIC, TRACEMAIN, END_METHOD, END_SIGNATURE, false);
        }
        mv.visitInsn(opcode);
    }
}