package com.andoter.asm_example.part6

import com.andoter.asm_example.utils.ClassOutputUtil

import org.objectweb.asm.ClassReader

import org.objectweb.asm.ClassWriter

import org.objectweb.asm.Opcodes

import org.objectweb.asm.tree.ClassNode

import org.objectweb.asm.tree.FieldNode

class AddFieldDemo {

}

fun main() {

val classReader = ClassReader("com.andoter.asm_example.part6.AddFieldDemo")

val classNode = ClassNode()

val addFieldTransform =

AddFieldTransform(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, "addField", "Ljava/lang/String;")

classReader.accept(classNode, ClassReader.SKIP_DEBUG)

addFieldTransform.transform(classNode)

// 尝试输出进行查看

val classWriter = ClassWriter(ClassWriter.COMPUTE_MAXS)

classNode.accept(classWriter)

//输出文件查看

ClassOutputUtil.byte2File("asm_example/files/AddFieldDemo.class", classWriter.toByteArray())

}

class AddFieldTransform(var filedAccess: Int, var fieldName: String, var fieldDesc: String) :

ClassTransformer() {

override fun transform(cn: ClassNode?) {

var isPresent = false

if (cn?.fields != null) {

for (fieldNode in cn.fields) {

if (fieldNode.name == fieldName) {

isPresent = true

break;

}

}

if (!isPresent) {

cn.fields.add(FieldNode(filedAccess, fieldName, fieldDesc, null, null))

}

}

super.transform(cn)

}

}