com.google.code.jconts.instrument.gen.StateClassGenerator.java Source code

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Here is the source code for com.google.code.jconts.instrument.gen.StateClassGenerator.java

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/**
 * Copyright (C) 2011 Ivan Dubrov
 *
 * 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 com.google.code.jconts.instrument.gen;

import static com.google.code.jconts.instrument.Constants.*;

import java.util.List;

import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

import com.google.code.jconts.instrument.context.MethodContext;
import com.google.code.jconts.instrument.util.TransformationContext;

/**
 * 
 * 
 */
public class StateClassGenerator {

    private final MethodContext info;

    public StateClassGenerator(MethodContext info) {
        this.info = info;
    }

    public void accept(TransformationContext context) {
        ClassVisitor cv = context.writer();

        final String name = info.stateClassName;

        cv.visit(Opcodes.V1_6, Opcodes.ACC_FINAL /*| Opcodes.ACC_SYNTHETIC*/, name, null, OBJECT_NAME, null);

        cv.visitSource(info.ownerSource, null);
        cv.visitOuterClass(info.owner, null, null);

        cv.visitField(0/*Opcodes.ACC_SYNTHETIC*/, CONTINUATION_FIELD, CONTINUATION_DESC,
                'L' + CONTINUATION_NAME + '<' + info.valueSignature + ">;", null);

        // Local variables state
        List<String> names = info.tracker.getFieldNames();
        List<Type> types = info.tracker.getFieldTypes();
        for (int i = 0; i < names.size(); ++i) {
            cv.visitField(0/*Opcodes.ACC_SYNTHETIC*/, names.get(i), types.get(i).getDescriptor(), null, null);
        }

        // Return value variable
        cv.visitField(0/*Opcodes.ACC_SYNTHETIC*/, "result", OBJECT_DESC, null, null);
        cv.visitField(0/*Opcodes.ACC_SYNTHETIC*/, "exception", THROWABLE_DESC, null, null);

        // Generate constructor
        MethodVisitor mv = cv.visitMethod(0, CTOR_NAME, DEFAULT_CTOR_DESC, null, null);
        mv.visitCode();
        Label start = new Label();
        Label end = new Label();
        mv.visitLabel(start);
        mv.visitLineNumber(0, start);

        mv.visitVarInsn(Opcodes.ALOAD, 0);
        mv.visitMethodInsn(Opcodes.INVOKESPECIAL, OBJECT_NAME, CTOR_NAME, DEFAULT_CTOR_DESC);
        mv.visitInsn(Opcodes.RETURN);
        mv.visitLabel(end);

        mv.visitLocalVariable("this", 'L' + name + ';', null, start, end, 0);

        mv.visitMaxs(1, 1);
        mv.visitEnd();

        cv.visitEnd();
    }
}