com.tsc9526.monalisa.tools.clazz.MelpAsm.java Source code

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Here is the source code for com.tsc9526.monalisa.tools.clazz.MelpAsm.java

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/*******************************************************************************************
 *   Copyright (c) 2016, zzg.zhou(11039850@qq.com)
 * 
 *  Monalisa is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
    
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Lesser General Public License for more details.
    
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *******************************************************************************************/
package com.tsc9526.monalisa.tools.clazz;

import java.io.IOException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.objectweb.asm.ClassReader;
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;

/**
 * Java8(ASM5)
 * 
 * @author zzg.zhou(11039850@qq.com)
 */
public class MelpAsm {
    static {
        MelpLib.loadClass(MelpLib.libAsmClass);
    }

    public static String[] getMethodParamNames(final Method m) {
        final String[] paramNames = new String[m.getParameterTypes().length];
        final String n = m.getDeclaringClass().getName();

        ClassReader cr = null;
        try {
            cr = new ClassReader(n);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        cr.accept(new ClassVisitor(Opcodes.ASM5) {
            public MethodVisitor visitMethod(final int access, final String name, final String desc,
                    final String signature, final String[] exceptions) {
                final Type[] args = Type.getArgumentTypes(desc);

                // ?????
                if (!name.equals(m.getName()) || !sameType(args, m.getParameterTypes())) {
                    return super.visitMethod(access, name, desc, signature, exceptions);
                }

                MethodVisitor v = super.visitMethod(access, name, desc, signature, exceptions);
                return new MethodVisitor(Opcodes.ASM5, v) {
                    public void visitLocalVariable(String name, String desc, String signature, Label start,
                            Label end, int index) {
                        int i = index - 1;
                        // ???
                        // ???"this"???
                        if (Modifier.isStatic(m.getModifiers())) {
                            i = index;
                        }

                        if (i >= 0) {
                            setParamName(paramNames, name);
                        }

                        super.visitLocalVariable(name, desc, signature, start, end, index);
                    }

                };
            }
        }, 0);

        return paramNames;
    }

    private static void setParamName(String[] paramNames, String name) {
        for (int i = 0; i < paramNames.length; i++) {
            if (paramNames[i] == null) {
                paramNames[i] = name;
                return;
            }
        }
    }

    private static boolean sameType(Type[] types, Class<?>[] clazzes) {
        // ??
        if (types.length != clazzes.length) {
            return false;
        }

        for (int i = 0; i < types.length; i++) {
            if (!Type.getType(clazzes[i]).equals(types[i])) {
                return false;
            }
        }
        return true;
    }
}