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Paper/patches/api/0008-Use-ASM-for-event-executors.patch
Noah van der Aa 2ef589c820
okaaay let's go
2024-10-22 18:23:19 +02:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Techcable <Techcable@outlook.com>
Date: Thu, 3 Mar 2016 13:20:33 -0700
Subject: [PATCH] Use ASM for event executors.
Uses method handles for private or static methods.
diff --git a/build.gradle.kts b/build.gradle.kts
index cce9caa52c9a2208acccbd25fa88c0de066f23a4..2b1d08d8e16037f6d17c74ea613eaa2ca36c664e 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -47,6 +47,9 @@ dependencies {
apiAndDocs("net.kyori:adventure-text-serializer-legacy")
apiAndDocs("net.kyori:adventure-text-serializer-plain")
apiAndDocs("net.kyori:adventure-text-logger-slf4j")
+
+ implementation("org.ow2.asm:asm:9.7.1")
+ implementation("org.ow2.asm:asm-commons:9.7.1")
// Paper end
compileOnly("org.apache.maven:maven-resolver-provider:3.9.6")
diff --git a/src/main/java/com/destroystokyo/paper/event/executor/MethodHandleEventExecutor.java b/src/main/java/com/destroystokyo/paper/event/executor/MethodHandleEventExecutor.java
new file mode 100644
index 0000000000000000000000000000000000000000..5a702481d28d90cb503faad0d9b9c3231bbff940
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/event/executor/MethodHandleEventExecutor.java
@@ -0,0 +1,46 @@
+package com.destroystokyo.paper.event.executor;
+
+import com.destroystokyo.paper.util.SneakyThrow;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Method;
+import org.bukkit.event.Event;
+import org.bukkit.event.EventException;
+import org.bukkit.event.Listener;
+import org.bukkit.plugin.EventExecutor;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@ApiStatus.Internal
+@NullMarked
+public class MethodHandleEventExecutor implements EventExecutor {
+
+ private final Class<? extends Event> eventClass;
+ private final MethodHandle handle;
+
+ public MethodHandleEventExecutor(final Class<? extends Event> eventClass, final MethodHandle handle) {
+ this.eventClass = eventClass;
+ this.handle = handle;
+ }
+
+ public MethodHandleEventExecutor(final Class<? extends Event> eventClass, final Method m) {
+ this.eventClass = eventClass;
+ try {
+ m.setAccessible(true);
+ this.handle = MethodHandles.lookup().unreflect(m);
+ } catch (final IllegalAccessException e) {
+ throw new AssertionError("Unable to set accessible", e);
+ }
+ }
+
+ @Override
+ public void execute(final Listener listener, final Event event) throws EventException {
+ if (!this.eventClass.isInstance(event)) return;
+ try {
+ this.handle.invoke(listener, event);
+ } catch (final Throwable t) {
+ SneakyThrow.sneaky(t);
+ }
+ }
+}
diff --git a/src/main/java/com/destroystokyo/paper/event/executor/StaticMethodHandleEventExecutor.java b/src/main/java/com/destroystokyo/paper/event/executor/StaticMethodHandleEventExecutor.java
new file mode 100644
index 0000000000000000000000000000000000000000..bbdb5b472df116b71c459bdc6cc4b74267ea0f5e
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/event/executor/StaticMethodHandleEventExecutor.java
@@ -0,0 +1,44 @@
+package com.destroystokyo.paper.event.executor;
+
+import com.destroystokyo.paper.util.SneakyThrow;
+import com.google.common.base.Preconditions;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import org.bukkit.event.Event;
+import org.bukkit.event.EventException;
+import org.bukkit.event.Listener;
+import org.bukkit.plugin.EventExecutor;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+@ApiStatus.Internal
+@NullMarked
+public class StaticMethodHandleEventExecutor implements EventExecutor {
+
+ private final Class<? extends Event> eventClass;
+ private final MethodHandle handle;
+
+ public StaticMethodHandleEventExecutor(final Class<? extends Event> eventClass, final Method m) {
+ Preconditions.checkArgument(Modifier.isStatic(m.getModifiers()), "Not a static method: %s", m);
+ Preconditions.checkArgument(eventClass != null, "eventClass is null");
+ this.eventClass = eventClass;
+ try {
+ m.setAccessible(true);
+ this.handle = MethodHandles.lookup().unreflect(m);
+ } catch (final IllegalAccessException e) {
+ throw new AssertionError("Unable to set accessible", e);
+ }
+ }
+
+ @Override
+ public void execute(final Listener listener, final Event event) throws EventException {
+ if (!this.eventClass.isInstance(event)) return;
+ try {
+ this.handle.invoke(event);
+ } catch (final Throwable throwable) {
+ SneakyThrow.sneaky(throwable);
+ }
+ }
+}
diff --git a/src/main/java/com/destroystokyo/paper/event/executor/asm/ASMEventExecutorGenerator.java b/src/main/java/com/destroystokyo/paper/event/executor/asm/ASMEventExecutorGenerator.java
new file mode 100644
index 0000000000000000000000000000000000000000..abfcb6e8383ff311940d82afe4ff990649a082dc
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/event/executor/asm/ASMEventExecutorGenerator.java
@@ -0,0 +1,59 @@
+package com.destroystokyo.paper.event.executor.asm;
+
+import java.lang.reflect.Method;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.bukkit.plugin.EventExecutor;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.Type;
+import org.objectweb.asm.commons.GeneratorAdapter;
+
+import static org.objectweb.asm.Opcodes.ACC_PUBLIC;
+import static org.objectweb.asm.Opcodes.INVOKEINTERFACE;
+import static org.objectweb.asm.Opcodes.INVOKESPECIAL;
+import static org.objectweb.asm.Opcodes.INVOKEVIRTUAL;
+import static org.objectweb.asm.Opcodes.V1_8;
+
+@ApiStatus.Internal
+@NullMarked
+public final class ASMEventExecutorGenerator {
+
+ private static final String EXECUTE_DESCRIPTOR = "(Lorg/bukkit/event/Listener;Lorg/bukkit/event/Event;)V";
+
+ public static byte[] generateEventExecutor(final Method m, final String name) {
+ final ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
+ writer.visit(V1_8, ACC_PUBLIC, name.replace('.', '/'), null, Type.getInternalName(Object.class), new String[]{Type.getInternalName(EventExecutor.class)});
+ // Generate constructor
+ GeneratorAdapter methodGenerator = new GeneratorAdapter(writer.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null), ACC_PUBLIC, "<init>", "()V");
+ methodGenerator.loadThis();
+ methodGenerator.visitMethodInsn(INVOKESPECIAL, Type.getInternalName(Object.class), "<init>", "()V", false); // Invoke the super class (Object) constructor
+ methodGenerator.returnValue();
+ methodGenerator.endMethod();
+ // Generate the execute method
+ methodGenerator = new GeneratorAdapter(writer.visitMethod(ACC_PUBLIC, "execute", EXECUTE_DESCRIPTOR, null, null), ACC_PUBLIC, "execute", EXECUTE_DESCRIPTOR);
+ methodGenerator.loadArg(0);
+ methodGenerator.checkCast(Type.getType(m.getDeclaringClass()));
+ methodGenerator.loadArg(1);
+ methodGenerator.checkCast(Type.getType(m.getParameterTypes()[0]));
+ methodGenerator.visitMethodInsn(m.getDeclaringClass().isInterface() ? INVOKEINTERFACE : INVOKEVIRTUAL, Type.getInternalName(m.getDeclaringClass()), m.getName(), Type.getMethodDescriptor(m), m.getDeclaringClass().isInterface());
+ // The only purpose of this switch statement is to generate the correct pop instruction, should the event handler method return something other than void.
+ // Non-void event handlers will be unsupported in a future release.
+ switch (Type.getType(m.getReturnType()).getSize()) {
+ // case 0 is omitted because the only type that has size 0 is void - no pop instruction needed.
+ case 1 -> methodGenerator.pop(); // handles reference types and most primitives
+ case 2 -> methodGenerator.pop2(); // handles long and double
+ }
+ methodGenerator.returnValue();
+ methodGenerator.endMethod();
+ writer.visitEnd();
+ return writer.toByteArray();
+ }
+
+ public static AtomicInteger NEXT_ID = new AtomicInteger(1);
+
+ public static String generateName() {
+ final int id = NEXT_ID.getAndIncrement();
+ return "com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor" + id;
+ }
+}
diff --git a/src/main/java/com/destroystokyo/paper/event/executor/asm/ClassDefiner.java b/src/main/java/com/destroystokyo/paper/event/executor/asm/ClassDefiner.java
new file mode 100644
index 0000000000000000000000000000000000000000..581561fbd32c81ab1774ba8f0b7f3cec9392d99a
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/event/executor/asm/ClassDefiner.java
@@ -0,0 +1,35 @@
+package com.destroystokyo.paper.event.executor.asm;
+
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+@ApiStatus.Internal
+@NullMarked
+public interface ClassDefiner {
+
+ /**
+ * Returns if the defined classes can bypass access checks
+ *
+ * @return if classes bypass access checks
+ */
+ default boolean isBypassAccessChecks() {
+ return false;
+ }
+
+ /**
+ * Define a class
+ *
+ * @param parentLoader the parent classloader
+ * @param name the name of the class
+ * @param data the class data to load
+ * @return the defined class
+ * @throws ClassFormatError if the class data is invalid
+ * @throws NullPointerException if any of the arguments are null
+ */
+ Class<?> defineClass(ClassLoader parentLoader, String name, byte[] data);
+
+ static ClassDefiner getInstance() {
+ return SafeClassDefiner.INSTANCE;
+ }
+
+}
diff --git a/src/main/java/com/destroystokyo/paper/event/executor/asm/SafeClassDefiner.java b/src/main/java/com/destroystokyo/paper/event/executor/asm/SafeClassDefiner.java
new file mode 100644
index 0000000000000000000000000000000000000000..48bcc72293c2a31b6e2dd2dcd6a79d618c72a137
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/event/executor/asm/SafeClassDefiner.java
@@ -0,0 +1,66 @@
+package com.destroystokyo.paper.event.executor.asm;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.MapMaker;
+import java.util.concurrent.ConcurrentMap;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+@ApiStatus.Internal
+@NullMarked
+public class SafeClassDefiner implements ClassDefiner {
+
+ /* default */ static final SafeClassDefiner INSTANCE = new SafeClassDefiner();
+
+ private SafeClassDefiner() {
+ }
+
+ private final ConcurrentMap<ClassLoader, GeneratedClassLoader> loaders = new MapMaker().weakKeys().makeMap();
+
+ @Override
+ public Class<?> defineClass(final ClassLoader parentLoader, final String name, final byte[] data) {
+ final GeneratedClassLoader loader = this.loaders.computeIfAbsent(parentLoader, GeneratedClassLoader::new);
+ synchronized (loader.getClassLoadingLock(name)) {
+ Preconditions.checkState(!loader.hasClass(name), "%s already defined", name);
+ final Class<?> c = loader.define(name, data);
+ assert c.getName().equals(name);
+ return c;
+ }
+ }
+
+ private static class GeneratedClassLoader extends ClassLoader {
+
+ static {
+ ClassLoader.registerAsParallelCapable();
+ }
+
+ protected GeneratedClassLoader(final ClassLoader parent) {
+ super(parent);
+ }
+
+ private Class<?> define(final String name, final byte[] data) {
+ synchronized (this.getClassLoadingLock(name)) {
+ assert !this.hasClass(name);
+ final Class<?> c = this.defineClass(name, data, 0, data.length);
+ this.resolveClass(c);
+ return c;
+ }
+ }
+
+ @Override
+ public Object getClassLoadingLock(final String name) {
+ return super.getClassLoadingLock(name);
+ }
+
+ public boolean hasClass(final String name) {
+ synchronized (this.getClassLoadingLock(name)) {
+ try {
+ Class.forName(name);
+ return true;
+ } catch (final ClassNotFoundException e) {
+ return false;
+ }
+ }
+ }
+ }
+}
diff --git a/src/main/java/org/bukkit/plugin/EventExecutor.java b/src/main/java/org/bukkit/plugin/EventExecutor.java
index a850f0780de05463fc0d3f9e15ff7f19d88b2aed..9026e108ccd3a88aee1267ee275137befa646455 100644
--- a/src/main/java/org/bukkit/plugin/EventExecutor.java
+++ b/src/main/java/org/bukkit/plugin/EventExecutor.java
@@ -5,9 +5,75 @@ import org.bukkit.event.EventException;
import org.bukkit.event.Listener;
import org.jetbrains.annotations.NotNull;
+// Paper start
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.function.Function;
+
+import com.destroystokyo.paper.event.executor.MethodHandleEventExecutor;
+import com.destroystokyo.paper.event.executor.StaticMethodHandleEventExecutor;
+import com.destroystokyo.paper.event.executor.asm.ASMEventExecutorGenerator;
+import com.destroystokyo.paper.event.executor.asm.ClassDefiner;
+import com.google.common.base.Preconditions;
+// Paper end
+
/**
* Interface which defines the class for event call backs to plugins
*/
public interface EventExecutor {
public void execute(@NotNull Listener listener, @NotNull Event event) throws EventException;
+
+ // Paper start
+ ConcurrentMap<Method, Class<? extends EventExecutor>> eventExecutorMap = new ConcurrentHashMap<Method, Class<? extends EventExecutor>>() {
+ @NotNull
+ @Override
+ public Class<? extends EventExecutor> computeIfAbsent(@NotNull Method key, @NotNull Function<? super Method, ? extends Class<? extends EventExecutor>> mappingFunction) {
+ Class<? extends EventExecutor> executorClass = get(key);
+ if (executorClass != null)
+ return executorClass;
+
+ //noinspection SynchronizationOnLocalVariableOrMethodParameter
+ synchronized (key) {
+ executorClass = get(key);
+ if (executorClass != null)
+ return executorClass;
+
+ return super.computeIfAbsent(key, mappingFunction);
+ }
+ }
+ };
+
+ @NotNull
+ public static EventExecutor create(@NotNull Method m, @NotNull Class<? extends Event> eventClass) {
+ Preconditions.checkNotNull(m, "Null method");
+ Preconditions.checkArgument(m.getParameterCount() != 0, "Incorrect number of arguments %s", m.getParameterCount());
+ Preconditions.checkArgument(m.getParameterTypes()[0] == eventClass, "First parameter %s doesn't match event class %s", m.getParameterTypes()[0], eventClass);
+ ClassDefiner definer = ClassDefiner.getInstance();
+ if (Modifier.isStatic(m.getModifiers())) {
+ return new StaticMethodHandleEventExecutor(eventClass, m);
+ } else if (definer.isBypassAccessChecks() || Modifier.isPublic(m.getDeclaringClass().getModifiers()) && Modifier.isPublic(m.getModifiers())) {
+ // get the existing generated EventExecutor class for the Method or generate one
+ Class<? extends EventExecutor> executorClass = eventExecutorMap.computeIfAbsent(m, (__) -> {
+ String name = ASMEventExecutorGenerator.generateName();
+ byte[] classData = ASMEventExecutorGenerator.generateEventExecutor(m, name);
+ return definer.defineClass(m.getDeclaringClass().getClassLoader(), name, classData).asSubclass(EventExecutor.class);
+ });
+
+ try {
+ EventExecutor asmExecutor = executorClass.newInstance();
+ // Define a wrapper to conform to bukkit stupidity (passing in events that don't match and wrapper exception)
+ return (listener, event) -> {
+ if (!eventClass.isInstance(event)) return;
+ asmExecutor.execute(listener, event);
+ };
+ } catch (InstantiationException | IllegalAccessException e) {
+ throw new AssertionError("Unable to initialize generated event executor", e);
+ }
+ } else {
+ return new MethodHandleEventExecutor(eventClass, m);
+ }
+ }
+ // Paper end
}
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