LibJF/libjf-unsafe-v0/src/main/java/io/gitlab/jfronny/libjf/unsafe/asm/AsmTransformer.java

package io.gitlab.jfronny.libjf.unsafe.asm;

import io.gitlab.jfronny.libjf.unsafe.asm.patch.Patch;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.tree.ClassNode;
import org.spongepowered.asm.mixin.transformer.FabricMixinTransformerProxy;
import org.spongepowered.asm.transformers.MixinClassWriter;

public class AsmTransformer extends FabricMixinTransformerProxy {
    public FabricMixinTransformerProxy delegate;
    public AsmConfig asmConfig;

    @Override
    public byte[] transformClassBytes(String name, String transformedName, byte[] classBytes) {
        classBytes = delegate.transformClassBytes(name, transformedName, classBytes);
        if (classBytes == null || name == null)
            return classBytes;
        if (name.startsWith("org.objectweb.asm")
                || name.startsWith("net.fabricmc.loader")
                || name.startsWith("net.minecraft")
                || name.startsWith("io.gitlab.jfronny.libjf.unsafe.asm")
                || name.startsWith("joptsimple")
        )
            return classBytes;

        ClassNode klass = new ClassNode();
        ClassReader reader = new ClassReader(classBytes);
        reader.accept(klass, ClassReader.EXPAND_FRAMES);

        for (Patch patch : asmConfig.getPatches()) {
            patch.apply(klass);
        }

        ClassWriter writer = new MixinClassWriter(reader, ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
        klass.accept(writer);
        classBytes = writer.toByteArray();
        return  classBytes;
    }
}