GameDataTransformer.java

/*
 * Copyright (c) 2017 NOVA, All rights reserved.
 * This library is free software, licensed under GNU Lesser General Public License version 3
 *
 * This file is part of NOVA.
 *
 * NOVA is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * NOVA 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with NOVA.  If not, see <http://www.gnu.org/licenses/>.
 */
package nova.core.wrapper.mc.forge.v18.asm.transformers;

import nova.core.wrapper.mc.forge.v18.asm.lib.ASMHelper;
import nova.core.wrapper.mc.forge.v18.asm.lib.ObfMapping;
import nova.internal.core.Game;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.JumpInsnNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.VarInsnNode;

/**
 * @author ExE Boss
 */
public class GameDataTransformer implements Transformer {

	@Override
	public void transform(ClassNode cnode) {
		Game.logger().info("Transforming GameData class for correct NOVA mod id mapping.");
		transformAddPrefix(cnode);
		transformRegisterBlock(cnode);
		transformRegisterItem(cnode);
	}

	private void transformAddPrefix(ClassNode cnode) {
		ObfMapping mapping = new ObfMapping("net/minecraftforge/fml/common/registry/GameData", "addPrefix", "(Ljava/lang/String;)Ljava/lang/String;");
		MethodNode method = ASMHelper.findMethod(mapping, cnode);

		if (method == null) {
			throw new IllegalStateException("[NOVA] Lookup " + mapping + " failed!");
		}

		Game.logger().info("Transforming method {}", method.name);

		@SuppressWarnings("unchecked")
		JumpInsnNode prev = (JumpInsnNode) method.instructions.get(49);

		InsnList list = new InsnList();
		list.add(new VarInsnNode(ALOAD, 4));
		list.add(new MethodInsnNode(INVOKESTATIC, "nova/core/wrapper/mc/forge/v18/asm/StaticForwarder", "isNovaPrefix", "(Ljava/lang/String;)Z", false));
		list.add(new JumpInsnNode(IFNE, prev.label));

		method.instructions.insert(prev, list);

		Game.logger().info("Injected instruction to method: {}", method.name);
	}

	private void transformRegisterBlock(ClassNode cnode) {
		ObfMapping obfMap = new ObfMapping("net/minecraftforge/fml/common/registry/GameData", "registerBlock", "(Latr;Ljava/lang/String;)I");
		ObfMapping deobfMap = new ObfMapping("net/minecraftforge/fml/common/registry/GameData", "registerBlock", "(Lnet/minecraft/block/Block;Ljava/lang/String;)I");

		MethodNode method = ASMHelper.findMethod(obfMap, cnode);

		if (method == null) {
			Game.logger().warn("Lookup {} failed. You are probably in a deobf environment.", obfMap);
			method = ASMHelper.findMethod(deobfMap, cnode);

			if (method == null) {
				throw new IllegalStateException("[NOVA] Lookup " + deobfMap + " failed!");
			}
		}

		Game.logger().info("Transforming method {}", method.name);

		@SuppressWarnings("unchecked")
		JumpInsnNode prev = (JumpInsnNode) method.instructions.get(12);

		InsnList list = new InsnList();
		list.add(new VarInsnNode(ALOAD, 2));
		list.add(new MethodInsnNode(INVOKESTATIC, "nova/core/wrapper/mc/forge/v18/asm/StaticForwarder", "hasNovaPrefix", "(Ljava/lang/String;)Z", false));
		list.add(new JumpInsnNode(IFNE, prev.label));

		method.instructions.insert(prev, list);

		Game.logger().info("Injected instruction to method: {}", method.name);
	}

	private void transformRegisterItem(ClassNode cnode) {
		ObfMapping obfMap = new ObfMapping("net/minecraftforge/fml/common/registry/GameData", "registerItem", "(Lalq;Ljava/lang/String;)I");
		ObfMapping deobfMap = new ObfMapping("net/minecraftforge/fml/common/registry/GameData", "registerItem", "(Lnet/minecraft/item/Item;Ljava/lang/String;)I");

		MethodNode method = ASMHelper.findMethod(obfMap, cnode);

		if (method == null) {
			Game.logger().warn("Lookup {} failed. You are probably in a deobf environment.", obfMap);
			method = ASMHelper.findMethod(deobfMap, cnode);

			if (method == null) {
				throw new IllegalStateException("[NOVA] Lookup " + deobfMap + " failed!");
			}
		}

		Game.logger().info("Transforming method {}", method.name);

		@SuppressWarnings("unchecked")
		JumpInsnNode prev = (JumpInsnNode) method.instructions.get(12);

		InsnList list = new InsnList();
		list.add(new VarInsnNode(ALOAD, 2));
		list.add(new MethodInsnNode(INVOKESTATIC, "nova/core/wrapper/mc/forge/v18/asm/StaticForwarder", "hasNovaPrefix", "(Ljava/lang/String;)Z", false));
		list.add(new JumpInsnNode(IFNE, prev.label));

		method.instructions.insert(prev, list);

		Game.logger().info("Injected instruction to method: {}", method.name);
	}
}