SelectiveTransformer.java

package coloredlightscore.src.asm.transformer.core;

import com.google.common.base.Throwables;
import cpw.mods.fml.common.FMLLog;
import net.minecraft.launchwrapper.IClassTransformer;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.tree.ClassNode;

public abstract class SelectiveTransformer implements IClassTransformer {
    @Override
    public final byte[] transform(String name, String transformedName, byte[] bytes) {
        if (bytes != null && transforms(transformedName)) {
            FMLLog.info("Class %s is a candidate for transforming", transformedName);

            try {
                ClassNode clazz = ASMUtils.getClassNode(bytes);
                if (transform(clazz, transformedName)) {
                    FMLLog.info("Transforming class " + transformedName);
                    ClassWriter writer = new ExtendedClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
                    clazz.accept(writer);
                    bytes = writer.toByteArray();
                } else
                    FMLLog.warning("Did not transform %s", transformedName);
            } catch (Exception e) {
                FMLLog.severe("Exception during transformation of class " + transformedName);
                e.printStackTrace();
                Throwables.propagate(e);
            }
        }
        return bytes;
    }

    protected abstract boolean transforms(String className);

    protected abstract boolean transform(ClassNode clazz, String className);
}