org.apache.commons.javaflow.providers.asm5.ContinuableClassVisitor.java Source code

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Here is the source code for org.apache.commons.javaflow.providers.asm5.ContinuableClassVisitor.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.javaflow.providers.asm5;

import org.apache.commons.javaflow.spi.ContinuableClassInfo;
import org.apache.commons.javaflow.spi.ContinuableClassInfoResolver;
import org.apache.commons.javaflow.spi.StopException;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * ContinuableClassVisitor
 * 
 * @author Evgueni Koulechov
 */
public class ContinuableClassVisitor extends ClassVisitor {

    final private ContinuableClassInfoResolver cciResolver;
    final private byte[] originalBytes;

    private String className;
    private ContinuableClassInfo classInfo;
    private boolean skipEnchancing = false;
    private boolean isInterface = false;

    public ContinuableClassVisitor(final ClassVisitor cv, final ContinuableClassInfoResolver cciResolver,
            final byte[] originalBytes) {
        super(Opcodes.ASM5, cv);
        this.cciResolver = cciResolver;
        this.originalBytes = originalBytes;
    }

    boolean skipEnchancing() {
        return skipEnchancing;
    }

    public void visit(int version, int access, String name, String signature, String superName,
            String[] interfaces) {
        isInterface = (access & Opcodes.ACC_INTERFACE) != 0;

        className = name;
        classInfo = cciResolver.resolve(name, originalBytes);

        if (null == classInfo || classInfo.isClassProcessed() || StopException
                .__dirtyCheckSkipContinuationsOnClass(version, access, name, signature, superName, interfaces)) {
            skipEnchancing = true;
            // Must exit by throwing exception, otherwise NPE is possible in nested visitor
            throw StopException.INSTANCE;
        }
        cv.visit(version, access, name, signature, superName, interfaces);
    }

    @Override
    public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {
        if (MaybeContinuableClassVisitor.MARKER_FIELD_NAME.equals(name) && (access & Opcodes.ACC_STATIC) != 0) {
            skipEnchancing = true;
            classInfo.markClassProcessed();
            throw StopException.INSTANCE;
        }
        return super.visitField(access, name, desc, signature, value);
    }

    @Override
    public void visitEnd() {
        if (!skipEnchancing) {
            super.visitField(
                    (isInterface ? Opcodes.ACC_PUBLIC : Opcodes.ACC_PRIVATE) + Opcodes.ACC_FINAL
                            + Opcodes.ACC_STATIC,
                    MaybeContinuableClassVisitor.MARKER_FIELD_NAME, "Ljava/lang/String;", null, "A").visitEnd();
        }
        super.visitEnd();
    }

    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        final MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
        final boolean skip = skipEnchancing || null == classInfo || mv == null
                || (access & (Opcodes.ACC_ABSTRACT | Opcodes.ACC_NATIVE)) > 0 || "<init>".equals(name)
                || !classInfo.isContinuableMethod(access, name, desc, signature);
        if (skip) {
            return mv;
        } else {
            return new ContinuableMethodNode(access, name, desc, signature, exceptions, className, cciResolver, mv);
        }
    }
}