ASM: a very small and fast Java bytecode manipulation framework
Copyright (c) 2000-2011 INRIA, France Telecom
All rights reserved.
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modification, are permitted provided that the following conditions
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   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holders nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm.optimizer;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Attribute;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.Remapper;
import org.objectweb.asm.commons.RemappingMethodAdapter;

A MethodVisitor that renames fields and methods, and removes debug info. 
Author:
Eugene Kuleshov/**
 * A {@link MethodVisitor} that renames fields and methods, and removes debug
 * info.
 * 
 * @author Eugene Kuleshov
 */
public class MethodOptimizer extends RemappingMethodAdapter implements Opcodes {

    private final ClassOptimizer classOptimizer;

    public MethodOptimizer(ClassOptimizer classOptimizer, int access,
            String desc, MethodVisitor mv, Remapper remapper) {
        super(access, desc, mv, remapper);
        this.classOptimizer = classOptimizer;
    }

    // ------------------------------------------------------------------------
    // Overridden methods
    // ------------------------------------------------------------------------

    @Override
    public AnnotationVisitor visitAnnotationDefault() {
        // remove annotations
        return null;
    }

    @Override
    public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
        // remove annotations
        return null;
    }

    @Override
    public AnnotationVisitor visitParameterAnnotation(final int parameter,
            final String desc, final boolean visible) {
        // remove annotations
        return null;
    }

    @Override
    public void visitLocalVariable(final String name, final String desc,
            final String signature, final Label start, final Label end,
            final int index) {
        // remove debug info
    }

    @Override
    public void visitLineNumber(final int line, final Label start) {
        // remove debug info
    }

    @Override
    public void visitFrame(int type, int local, Object[] local2, int stack,
            Object[] stack2) {
        // remove frame info
    }

    @Override
    public void visitAttribute(Attribute attr) {
        // remove non standard attributes
    }

    @Override
    public void visitLdcInsn(Object cst) {
        if (!(cst instanceof Type)) {
            super.visitLdcInsn(cst);
            return;
        }

        // transform Foo.class to foo$(class) for 1.2 compatibility
        String ldcName = ((Type) cst).getInternalName();
        String fieldName = "class$" + ldcName.replace('/', '$');

        FieldVisitor fv = classOptimizer.syntheticFieldVisitor(ACC_STATIC
                | ACC_SYNTHETIC, fieldName, "Ljava/lang/Class;");
        fv.visitEnd();

        if (!classOptimizer.class$) {
            MethodVisitor mv = classOptimizer.visitMethod(ACC_STATIC
                    | ACC_SYNTHETIC, "class$",
                    "(Ljava/lang/String;)Ljava/lang/Class;", null, null);
            mv.visitCode();
            Label l0 = new Label();
            Label l1 = new Label();
            Label l2 = new Label();
            mv.visitTryCatchBlock(l0, l1, l2,
                    "java/lang/ClassNotFoundException");
            mv.visitLabel(l0);
            mv.visitVarInsn(ALOAD, 0);
            mv.visitMethodInsn(INVOKESTATIC, "java/lang/Class", "forName",
                    "(Ljava/lang/String;)Ljava/lang/Class;");
            mv.visitLabel(l1);
            mv.visitInsn(ARETURN);
            mv.visitLabel(l2);
            mv.visitMethodInsn(INVOKEVIRTUAL,
                    "java/lang/ClassNotFoundException", "getMessage",
                    "()Ljava/lang/String;");
            mv.visitVarInsn(ASTORE, 1);
            mv.visitTypeInsn(NEW, "java/lang/NoClassDefFoundError");
            mv.visitInsn(DUP);
            mv.visitVarInsn(ALOAD, 1);
            mv.visitMethodInsn(INVOKESPECIAL, "java/lang/NoClassDefFoundError",
                    "<init>", "(Ljava/lang/String;)V");
            mv.visitInsn(ATHROW);
            mv.visitMaxs(3, 2);
            mv.visitEnd();

            classOptimizer.class$ = true;
        }

        String clsName = classOptimizer.clsName;
        mv.visitFieldInsn(GETSTATIC, clsName, fieldName, "Ljava/lang/Class;");
        Label elseLabel = new Label();
        mv.visitJumpInsn(IFNONNULL, elseLabel);
        mv.visitLdcInsn(ldcName.replace('/', '.'));
        mv.visitMethodInsn(INVOKESTATIC, clsName, "class$",
                "(Ljava/lang/String;)Ljava/lang/Class;");
        mv.visitInsn(DUP);
        mv.visitFieldInsn(PUTSTATIC, clsName, fieldName, "Ljava/lang/Class;");
        Label endLabel = new Label();
        mv.visitJumpInsn(GOTO, endLabel);
        mv.visitLabel(elseLabel);
        mv.visitFieldInsn(GETSTATIC, clsName, fieldName, "Ljava/lang/Class;");
        mv.visitLabel(endLabel);
    }
}