reworked class transformer

src/main/java/mods/betterfoliage/loader/EZTransformerBase.java

@@ -0,0 +1,128 @@
+package mods.betterfoliage.loader;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.lang.reflect.Method;
+
+import net.minecraft.launchwrapper.IClassTransformer;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.ClassNode;
+import org.objectweb.asm.tree.InsnList;
+import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+
+public class EZTransformerBase implements IClassTransformer {
+
+	public static interface IInstructionMatch {
+		public boolean matches(AbstractInsnNode node);
+	}
+	
+	@Retention(RetentionPolicy.RUNTIME)
+	public static @interface MethodMatch {
+		public String name();
+		public String signature();
+	}
+	
+	@Target(ElementType.METHOD)
+	@Retention(RetentionPolicy.RUNTIME)
+	public static @interface MethodTransform {
+		public String className();
+		public MethodMatch deobf();
+		public MethodMatch obf();
+		public String log();
+	}
+	
+	protected Logger logger = LogManager.getLogger(getClass().getSimpleName());
+	
+	public byte[] transform(String name, String transformedName, byte[] basicClass) {
+		// read class
+		ClassNode classNode = new ClassNode();
+        ClassReader classReader = new ClassReader(basicClass);
+        classReader.accept(classNode, 0);
+        boolean hasTransformed = false;
+        
+		for (Method classMethod : getClass().getMethods()) {
+			// check for annotated method with correct signature
+			MethodTransform annot = classMethod.getAnnotation(MethodTransform.class);
+			if (annot == null) continue;
+			if (classMethod.getParameterTypes().length != 2) continue;
+			if (!classMethod.getParameterTypes()[0].equals(MethodNode.class)) continue;
+			if (!classMethod.getParameterTypes()[1].equals(boolean.class)) continue;
+			
+			// try to find specified method in class
+			if (!transformedName.equals(annot.className())) continue;
+			for (MethodNode methodNode : classNode.methods) {
+				Boolean obf = null;
+				if (methodNode.name.equals(annot.obf().name()) && methodNode.desc.equals(annot.obf().signature())) {
+					obf = true;
+				} else if (methodNode.name.equals(annot.deobf().name()) && methodNode.desc.equals(annot.deobf().signature())) {
+					obf = false;
+				}
+				
+				if (obf != null) {
+					// transform
+					hasTransformed = true;
+					try {
+						classMethod.invoke(this, new Object[] {methodNode, obf});
+						logger.info(String.format("%s: SUCCESS", annot.log()));
+					} catch (Exception e) {
+						logger.info(String.format("%s: FAILURE", annot.log()));
+					}
+					break;
+				}
+			}
+		}
+		
+		// return result
+		ClassWriter writer = new ClassWriter(0);
+		if (hasTransformed) classNode.accept(writer);
+		return !hasTransformed ? basicClass : writer.toByteArray();
+	}
+
+	protected AbstractInsnNode findNext(AbstractInsnNode start, IInstructionMatch match) {
+		AbstractInsnNode current = start;
+		while(current != null) {
+			if (match.matches(current)) break;
+			current = current.getNext();
+		}
+		return current;
+	}
+	
+	protected AbstractInsnNode findPrevious(AbstractInsnNode start, IInstructionMatch match) {
+		AbstractInsnNode current = start;
+		while(current != null) {
+			if (match.matches(current)) break;
+			current = current.getPrevious();
+		}
+		return current;
+	}
+	
+	protected static IInstructionMatch matchInvokeAny() {
+		return new IInstructionMatch() {
+			public boolean matches(AbstractInsnNode node) {
+				return node instanceof MethodInsnNode;
+			}
+		};
+	}
+	
+	protected static IInstructionMatch matchOpcode(final int opcode) {
+		return new IInstructionMatch() {
+			public boolean matches(AbstractInsnNode node) {
+				return node.getOpcode() == opcode;
+			}
+		};
+	}
+	
+	protected static void insertAfter(InsnList insnList, AbstractInsnNode node, AbstractInsnNode... added) {
+		InsnList listAdd = new InsnList();
+		for (AbstractInsnNode inst : added) listAdd.add(inst);
+		insnList.insert(node, listAdd);
+	}
+}