ASM and Reflection

Main.java

/*
 * © Copyright 2015 -  SourceClear Inc
 */


import com.codepoetics.protonpack.StreamUtils;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;
import java.util.stream.Stream;

/**
 *
 */
public class Main {
  public static void main(String[] args) throws IOException {
    InputStream is = Main.class.getClassLoader().getResourceAsStream("dotclass.jar");
    List<Type> reflectedClasses = new ArrayList<>();
    List<String> reflectedMethods = new ArrayList<>();
    StreamUtils.takeUntil(jarToClassReaders(is), x -> x == null).
        forEach(cr -> cr.accept(new ReflectionClassVisitor(Opcodes.ASM5, reflectedClasses, reflectedMethods), Opcodes.ASM5));

    is = Main.class.getClassLoader().getResourceAsStream("classForName.jar");
    StreamUtils.takeUntil(jarToClassReaders(is), x -> x == null).
        forEach(cr -> cr.accept(new ReflectionClassVisitor(Opcodes.ASM5, reflectedClasses, reflectedMethods), Opcodes.ASM5));

    System.out.println(reflectedClasses);
    System.out.println(reflectedMethods);
  }

  static Stream<ClassReader> jarToClassReaders(InputStream jar) throws IOException {
    JarInputStream jis = new JarInputStream(jar);
    return Stream.generate(() -> {
      try {
        JarEntry jarEntry = jis.getNextJarEntry();
        if (jarEntry != null &&
            !jarEntry.isDirectory() &&
            jarEntry.getName().toLowerCase().endsWith(".class")) {
          ClassReader cr = new ClassReader(jis);
          return cr;
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
      return null;
    });
  }
}

ReflectionClassVisitor.java

/*
 * © Copyright 2015 -  SourceClear Inc
 */

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

import java.util.Collection;

/**
 *
 */
public class ReflectionClassVisitor extends ClassVisitor {

  ///////////////////////////// Class Attributes \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  ////////////////////////////// Class Methods \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  //////////////////////////////// Attributes \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  private final int version;
  private final Collection<Type> reflectedClasses;
  private final Collection<String> reflectedMethods;

  /////////////////////////////// Constructors \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  public ReflectionClassVisitor(int version, Collection<Type> reflectedClasses, Collection<String> reflectedMethods) {
    super(version);
    this.version = version;
    this.reflectedClasses = reflectedClasses;
    this.reflectedMethods = reflectedMethods;
  }

  ////////////////////////////////// Methods \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  //------------------------ Implements:

  //------------------------ Overrides:

  @Override
  public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
    return new ReflectionMethodVisitor(version, reflectedClasses, reflectedMethods);
  }

  //---------------------------- Abstract Methods -----------------------------

  //---------------------------- Utility Methods ------------------------------

  //---------------------------- Property Methods -----------------------------
}

ReflectionMethodVisitor.java

/*
 * © Copyright 2015 -  SourceClear Inc
 */

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

import java.util.Collection;
import java.util.regex.Pattern;

/**
 *
 */
public class ReflectionMethodVisitor extends MethodVisitor {

  ///////////////////////////// Class Attributes \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  ////////////////////////////// Class Methods \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  //////////////////////////////// Attributes \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  private final Collection<Type> reflectedClasses;
  private final Collection<String> reflectedMethods;
  private String currentLoadedString;

  /////////////////////////////// Constructors \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  public ReflectionMethodVisitor(int version, Collection<Type> reflectedClasses, Collection<String> reflectedMethods) {
    super(version);
    this.reflectedClasses = reflectedClasses;
    this.reflectedMethods = reflectedMethods;
  }

  ////////////////////////////////// Methods \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

  //------------------------ Implements:

  //------------------------ Overrides:

  @Override
  public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf) {
    if (opcode == Opcodes.INVOKEVIRTUAL &&
        owner.equals("java/lang/Class") &&
        name.equals("getMethod") &&
        desc.equals("(Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Method;")) {
      reflectedMethods.add(currentLoadedString);
    } else if (opcode == Opcodes.INVOKEVIRTUAL &&
        owner.equals("java/lang/reflect/Method") &&
        name.equals("invoke") &&
        desc.equals("(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;")) {
      System.out.println("invoke called!");
    } else if (opcode == Opcodes.INVOKESTATIC &&
        owner.equals("java/lang/Class") &&
        name.equals("forName") &&
        desc.equals("(Ljava/lang/String;)Ljava/lang/Class;")) {
      reflectedClasses.add(Type.getObjectType(classNameToInternalName(currentLoadedString)));
    }
  }

  private String classNameToInternalName(String className) {
    return className.replaceAll(Pattern.quote("."), "/");
  }

  @Override
  public void visitLdcInsn(Object arg) {
    if (arg instanceof Type) {
      Type type = (Type) arg;
      if (type.getSort() == Type.OBJECT) {
        reflectedClasses.add(type);
      }
    } else if (arg instanceof String) {
      currentLoadedString = (String) arg;
    }
  }

  //---------------------------- Abstract Methods -----------------------------

  //---------------------------- Utility Methods ------------------------------

  //---------------------------- Property Methods -----------------------------
}