Added proper history details for transforming, so we can see the transformer history of a class, backed by a debug option...

Author: RealMangorage

build.gradle

@@ -60,7 +60,7 @@ repositories {
 }
 
 dependencies {
-    compileOnly("org.mangorage:mangobotbootstrap:1.0.85")
+    compileOnly("org.mangorage:mangobotbootstrap:1.0.86")
 }
 
 test {

src/main/java/module-info.java

@@ -1,5 +1,6 @@
 module org.mangorage.mangobotlaunchtarget {
     requires org.mangorage.bootstrap;
+    requires java.logging;
 
     opens org.mangorage.mangobotlaunch.launch to org.mangorage.bootstrap;
     opens org.mangorage.mangobotlaunch.util to org.mangorage.bootstrap;

src/main/java/org/mangorage/mangobotlaunch/launch/ClassTransformers.java

@@ -1,47 +1,68 @@
 package org.mangorage.mangobotlaunch.launch;
 
 import org.mangorage.bootstrap.api.transformer.IClassTransformer;
+import org.mangorage.bootstrap.api.transformer.IClassTransformerHistory;
+import org.mangorage.bootstrap.api.transformer.ITransformerResultHistory;
 import org.mangorage.bootstrap.api.transformer.TransformResult;
 import org.mangorage.bootstrap.api.transformer.TransformerFlag;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
-public final class ClassTransformers {
+public final class ClassTransformers implements IClassTransformerHistory {
 
+    private static final Logger LOGGER = Logger.getLogger(ClassTransformers.class.getName());
     private static final boolean DEBUG_CLASS_TRANSFORMING = Boolean.getBoolean("DEBUG_CLASS_TRANSFORMING");
 
+    record TransformerHistoryEntry(Class<?> transformer, String transformerName, TransformerFlag transformerFlag, byte[] classData)
+            implements ITransformerResultHistory {}
 
     private final List<IClassTransformer> transformers = new CopyOnWriteArrayList<>();
-
+    private final Map<String, List<ITransformerResultHistory>> transformerHistoryCache = DEBUG_CLASS_TRANSFORMING ? new HashMap<>() : null;
 
     ClassTransformers() {}
 
     void add(IClassTransformer transformer) {
         transformers.add(transformer);
+        LOGGER.log(Level.INFO, "Added transformer: {0}", transformer.getName());
     }
 
     byte[] transform(String name, byte[] classData) {
+        if (transformers.isEmpty()) {
+            LOGGER.log(Level.FINE, "No transformers registered for class: {0}", name);
+            return null;
+        }
 
         for (IClassTransformer transformer : transformers) {
 
             TransformResult result = transformer.transform(name, classData);
 
-            if (DEBUG_CLASS_TRANSFORMING) {
-                // TODO: Implement this
+            if (DEBUG_CLASS_TRANSFORMING && transformerHistoryCache != null) {
+                transformerHistoryCache.computeIfAbsent(name, k -> new CopyOnWriteArrayList<>())
+                        .add(new TransformerHistoryEntry(transformer.getClass(), transformer.getName(), result.flag(), result.classData()));
+                LOGGER.log(Level.FINE, "Transformer history recorded for {0} using {1}", new Object[]{name, transformer.getName()});
             }
 
             if (result.flag() != TransformerFlag.NO_REWRITE) {
-                System.out.println(
-                        "%s Transformed %s"
-                                .formatted(transformer.getName(), name)
-                );
-
+                LOGGER.log(Level.INFO, "Class {0} transformed by {1}", new Object[]{name, transformer.getName()});
                 return result.classData();
             }
         }
 
+        LOGGER.log(Level.FINE, "No transformation applied to class: {0}", name);
+
         return null;
     }
 
+    @Override
+    public List<ITransformerResultHistory> getHistory(String className) {
+        if (!DEBUG_CLASS_TRANSFORMING || transformerHistoryCache == null) {
+            return List.of();
+        }
+        return transformerHistoryCache.getOrDefault(className, List.of());
+    }
 }

src/main/java/org/mangorage/mangobotlaunch/launch/MangoLoaderImpl.java

@@ -3,6 +3,7 @@
 import org.mangorage.bootstrap.api.loader.IMangoLoader;
 import org.mangorage.bootstrap.api.module.IModuleConfigurator;
 import org.mangorage.bootstrap.api.transformer.IClassTransformer;
+import org.mangorage.bootstrap.api.transformer.IClassTransformerHistory;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -152,6 +153,11 @@ protected Class<?> findClass(String moduleName, String name) {
         return null;
     }
 
+    @Override
+    public IClassTransformerHistory getTransformerHistory() {
+        return transformers;
+    }
+
     @Override
     public byte[] getClassBytes(String cn) {
         LoadedModule loadedModule = findLoadedModule(cn);
@@ -190,9 +196,7 @@ private Class<?> defineClass(String cn, LoadedModule loadedModule) {
             byte[] modifiedClassBytes = transformers.transform(cn, classBytes);
 
             if (modifiedClassBytes != null) {
-                Class<?> clz = defineClass(cn, modifiedClassBytes, 0, modifiedClassBytes.length);
-                transformers.add(cn, clz);
-                return clz;
+                return defineClass(cn, modifiedClassBytes, 0, modifiedClassBytes.length);
             }
             return defineClass(cn, classBytes, 0, classBytes.length);
         } catch (IOException ioe) {