Remove reliance on JDK internals in ClassFactory (#58)

MinecraftForge · Aug 20, 2024 · 6fb1fcc · 6fb1fcc
1 parent 6d0589d
commit 6fb1fcc
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Showing 4 changed files with 37 additions and 32 deletions.
diff --git a/...s-test-jar/src/main/java/net/minecraftforge/eventbus/testjar/benchmarks/ClassFactory.java b/...s-test-jar/src/main/java/net/minecraftforge/eventbus/testjar/benchmarks/ClassFactory.java
@@ -6,29 +6,30 @@
 package net.minecraftforge.eventbus.testjar.benchmarks;
 
 import java.io.IOException;
-import java.lang.reflect.Method;
+import java.lang.invoke.MethodHandles;
 
 import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.ClassWriter;
 import org.objectweb.asm.commons.ClassRemapper;
 import org.objectweb.asm.commons.Remapper;
 
-import net.minecraftforge.unsafe.UnsafeHacks;
-
-public class ClassFactory<T> {
+public final class ClassFactory<T> {
     private final Mapper<T> mapper;
     private final String binaryName;
-    private final String name;
     private final byte[] data;
-    private final Method define;
+    private final MethodHandles.Lookup lookup;
     private int count;
 
-    public ClassFactory(String name, Mapper<T> mapper) {
+    /**
+     * @param clazz The class to create new derivations of
+     * @param lookup {@code MethodHandles.lookup()} for defining the new classes
+     * @param mapper A function to apply on newly defined classes
+     */
+    public ClassFactory(Class<?> clazz, MethodHandles.Lookup lookup, Mapper<T> mapper) {
         this.mapper = mapper;
-        this.name = name;
-        this.binaryName = name.replace('.', '/');
+        this.binaryName = clazz.getName().replace('.', '/');
         this.data = readData(this.binaryName);
-        this.define = getAccess();
+        this.lookup = lookup;
     }
 
     private static byte[] readData(String name) {
@@ -40,24 +41,13 @@ private static byte[] readData(String name) {
         }
     }
 
-    private static Method getAccess() {
-        try {
-            var define = ClassLoader.class.getDeclaredMethod("defineClass", String.class, byte[].class, int.class, int.class);
-            UnsafeHacks.setAccessible(define);
-            return define;
-        } catch (Exception e) {
-            return sneak(e);
-        }
-    }
-
     public T create() {
         count++;
-        var newName = this.binaryName + "$New" + count;
 
         var renamer = new Remapper() {
             @Override
             public String map(String internalName) {
-                if (internalName.equals(binaryName)) return newName;
+                if (internalName.equals(binaryName)) return binaryName + "$New" + count;
                 return BenchmarkManager.rename(internalName);
             }
         };
@@ -66,9 +56,8 @@ public String map(String internalName) {
         var writer = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
         reader.accept(new ClassRemapper(writer, renamer), 0);
         try {
-            var cl = Thread.currentThread().getContextClassLoader();
             var newData = writer.toByteArray();
-            var newCls = (Class<?>)define.invoke(cl, this.name + "$New" + count, newData, 0, newData.length);
+            var newCls = (Class<?>) lookup.defineClass(newData);
             return mapper.apply(newCls);
         } catch (Exception e) {
             return sneak(e);
@@ -77,10 +66,11 @@ public String map(String internalName) {
 
     @SuppressWarnings("unchecked")
     private static <E extends Throwable, R> R sneak(Throwable e) throws E {
-        throw (E)e;
+        throw (E) e;
     }
 
-    public static interface Mapper<T> {
+    @FunctionalInterface
+    public interface Mapper<T> {
         T apply(Class<?> cls) throws Exception;
     }
 }
diff --git a/...-jar/src/main/java/net/minecraftforge/eventbus/testjar/subscribers/SubscriberDynamic.java b/...-jar/src/main/java/net/minecraftforge/eventbus/testjar/subscribers/SubscriberDynamic.java
@@ -6,6 +6,7 @@
 package net.minecraftforge.eventbus.testjar.subscribers;
 
 
+import java.lang.invoke.MethodHandles;
 import java.util.function.Consumer;
 
 import net.minecraftforge.eventbus.api.IEventBus;
@@ -26,9 +27,13 @@ public void onResultEvent(ResultEvent event) { }
     public void onSimpleEvent(EventWithData event) { }
 
     public static class Factory {
-        public static final ClassFactory<Consumer<IEventBus>> REGISTER = new ClassFactory<>("net.minecraftforge.eventbus.testjar.subscribers.SubscriberDynamic", cls -> {
-            var inst = cls.getConstructor().newInstance();
-            return bus -> bus.register(inst);
-        });
+        public static final ClassFactory<Consumer<IEventBus>> REGISTER = new ClassFactory<>(
+                SubscriberDynamic.class,
+                MethodHandles.lookup(),
+                cls -> {
+                    var inst = cls.getConstructor().newInstance();
+                    return bus -> bus.register(inst);
+                }
+        );
     }
 }
diff --git a/...t-jar/src/main/java/net/minecraftforge/eventbus/testjar/subscribers/SubscriberLambda.java b/...t-jar/src/main/java/net/minecraftforge/eventbus/testjar/subscribers/SubscriberLambda.java
@@ -5,6 +5,7 @@
 
 package net.minecraftforge.eventbus.testjar.subscribers;
 
+import java.lang.invoke.MethodHandles;
 import java.util.function.Consumer;
 
 import net.minecraftforge.eventbus.api.IEventBus;
@@ -29,6 +30,10 @@ public static void onSimpleEvent(EventWithData event) { }
 
     public static class Factory {
         @SuppressWarnings("unchecked")
-        public static final ClassFactory<Consumer<IEventBus>> REGISTER = new ClassFactory<>("net.minecraftforge.eventbus.testjar.subscribers.SubscriberLambda", cls -> (Consumer<IEventBus>)cls.getDeclaredField("register").get(null));
+        public static final ClassFactory<Consumer<IEventBus>> REGISTER = new ClassFactory<>(
+                SubscriberLambda.class,
+                MethodHandles.lookup(),
+                cls -> (Consumer<IEventBus>) cls.getDeclaredField("register").get(null)
+        );
     }
 }
diff --git a/...t-jar/src/main/java/net/minecraftforge/eventbus/testjar/subscribers/SubscriberStatic.java b/...t-jar/src/main/java/net/minecraftforge/eventbus/testjar/subscribers/SubscriberStatic.java
@@ -6,6 +6,7 @@
 package net.minecraftforge.eventbus.testjar.subscribers;
 
 
+import java.lang.invoke.MethodHandles;
 import java.util.function.Consumer;
 
 import net.minecraftforge.eventbus.api.IEventBus;
@@ -26,6 +27,10 @@ public static void onResultEvent(ResultEvent event) { }
     public static void onSimpleEvent(EventWithData event) { }
 
     public static class Factory {
-        public static final ClassFactory<Consumer<IEventBus>> REGISTER = new ClassFactory<>("net.minecraftforge.eventbus.testjar.subscribers.SubscriberStatic", cls -> bus -> bus.register(cls));
+        public static final ClassFactory<Consumer<IEventBus>> REGISTER = new ClassFactory<>(
+                SubscriberStatic.class,
+                MethodHandles.lookup(),
+                cls -> bus -> bus.register(cls)
+        );
     }
 }