net.enilink.composition.asm.util.InsnListGenerator.java Source code

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Here is the source code for net.enilink.composition.asm.util.InsnListGenerator.java

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/*
 * Copyright (c) 2009-2010 Ken Wenzel
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package net.enilink.composition.asm.util;

import java.util.Stack;

import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.GeneratorAdapter;
import org.objectweb.asm.commons.Method;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.MethodNode;

/**
 * Extension of {@link GeneratorAdapter} to allow the generation of
 * {@link InsnList}s.
 * 
 * @author Ken Wenzel
 * 
 */
public class InsnListGenerator extends org.objectweb.asm.commons.GeneratorAdapter {
    public InsnList instructions;

    protected MethodNode mn;
    protected Stack<InsnList> stack;

    public InsnListGenerator(MethodNode mn) {
        super(Opcodes.ASM5, mn, mn.access, mn.name, mn.desc);
        this.mn = mn;
        this.instructions = mn.instructions;
    }

    public InsnListGenerator(int access, String name, String desc, String signature, String[] exceptions) {
        this(new MethodNode(access, name, desc, signature, exceptions));
    }

    public InsnListGenerator(int access, String name, String desc) {
        this(access, name, desc, null, null);
    }

    public InsnList pushInsns() {
        if (stack == null) {
            stack = new Stack<InsnList>();
        }
        stack.push(instructions);
        instructions = new InsnList();

        return instructions;
    }

    public InsnList popInsns() {
        if (stack == null || stack.isEmpty()) {
            throw new IllegalStateException("Cannot restore instructions from empty stack");
        }
        instructions = stack.pop();

        return instructions;
    }

    public InsnList peekInsns() {
        if (stack == null || stack.isEmpty()) {
            throw new IllegalStateException("Cannot restore instructions from empty stack");
        }

        return stack.peek();
    }

    /**
     * Generates the instruction to invoke a specific method.
     * 
     * @param type
     *            the class in which the method is defined.
     * @param method
     *            the method to be invoked.
     */
    public void invokeSpecial(final Type type, final Method method) {
        super.invokeConstructor(type, method);
    }

    public void loadArray(Type[] types) {
        Type classType = Type.getType(Class.class);
        push(types.length);
        newArray(classType);
        for (int i = 0; i < types.length; i++) {
            dup();
            push(i);
            push(types[i]);
            arrayStore(classType);
        }
    }
}