131 lines
4.4 KiB
Java
131 lines
4.4 KiB
Java
package net.minecraftforge.event;
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import static org.objectweb.asm.Opcodes.*;
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import java.lang.reflect.Method;
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import java.util.HashMap;
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import org.objectweb.asm.ClassWriter;
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import org.objectweb.asm.MethodVisitor;
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import org.objectweb.asm.Type;
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import com.google.common.collect.Maps;
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public class ASMEventHandler implements IEventListener
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{
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private static int IDs = 0;
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private static final String HANDLER_DESC = Type.getInternalName(IEventListener.class);
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private static final String HANDLER_FUNC_DESC = Type.getMethodDescriptor(IEventListener.class.getDeclaredMethods()[0]);
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private static final ASMClassLoader LOADER = new ASMClassLoader();
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private static final HashMap<Method, Class<?>> cache = Maps.newHashMap();
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private final IEventListener handler;
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private final ForgeSubscribe subInfo;
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public ASMEventHandler(Object target, Method method) throws Exception
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{
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handler = (IEventListener)createWrapper(method).getConstructor(Object.class).newInstance(target);
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subInfo = method.getAnnotation(ForgeSubscribe.class);
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}
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@Override
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public void invoke(Event event)
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{
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if (handler != null)
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{
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if (!event.isCancelable() || !event.isCanceled() || subInfo.receiveCanceled())
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{
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handler.invoke(event);
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}
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}
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}
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public EventPriority getPriority()
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{
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return subInfo.priority();
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}
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public Class<?> createWrapper(Method callback)
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{
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if (cache.containsKey(callback))
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{
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return cache.get(callback);
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}
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ClassWriter cw = new ClassWriter(0);
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MethodVisitor mv;
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String name = getUniqueName(callback);
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String desc = name.replace('.', '/');
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String instType = Type.getInternalName(callback.getDeclaringClass());
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String eventType = Type.getInternalName(callback.getParameterTypes()[0]);
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/*
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System.out.println("Name: " + name);
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System.out.println("Desc: " + desc);
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System.out.println("InstType: " + instType);
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System.out.println("Callback: " + callback.getName() + Type.getMethodDescriptor(callback));
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System.out.println("Event: " + eventType);
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*/
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cw.visit(V1_6, ACC_PUBLIC | ACC_SUPER, desc, null, "java/lang/Object", new String[]{ HANDLER_DESC });
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cw.visitSource(".dynamic", null);
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{
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cw.visitField(ACC_PUBLIC, "instance", "Ljava/lang/Object;", null, null).visitEnd();
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}
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{
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mv = cw.visitMethod(ACC_PUBLIC, "<init>", "(Ljava/lang/Object;)V", null, null);
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mv.visitCode();
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mv.visitVarInsn(ALOAD, 0);
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mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
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mv.visitVarInsn(ALOAD, 0);
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mv.visitVarInsn(ALOAD, 1);
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mv.visitFieldInsn(PUTFIELD, desc, "instance", "Ljava/lang/Object;");
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mv.visitInsn(RETURN);
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mv.visitMaxs(2, 2);
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mv.visitEnd();
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}
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{
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mv = cw.visitMethod(ACC_PUBLIC, "invoke", HANDLER_FUNC_DESC, null, null);
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mv.visitCode();
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mv.visitVarInsn(ALOAD, 0);
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mv.visitFieldInsn(GETFIELD, desc, "instance", "Ljava/lang/Object;");
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mv.visitTypeInsn(CHECKCAST, instType);
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mv.visitVarInsn(ALOAD, 1);
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mv.visitTypeInsn(CHECKCAST, eventType);
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mv.visitMethodInsn(INVOKEVIRTUAL, instType, callback.getName(), Type.getMethodDescriptor(callback));
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mv.visitInsn(RETURN);
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mv.visitMaxs(2, 2);
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mv.visitEnd();
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}
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cw.visitEnd();
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Class<?> ret = LOADER.define(name, cw.toByteArray());
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cache.put(callback, ret);
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return ret;
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}
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private String getUniqueName(Method callback)
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{
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return String.format("%s_%d_%s_%s_%s", getClass().getName(), IDs++,
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callback.getDeclaringClass().getSimpleName(),
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callback.getName(),
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callback.getParameterTypes()[0].getSimpleName());
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}
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private static class ASMClassLoader extends ClassLoader
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{
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private ASMClassLoader()
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{
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super(ASMClassLoader.class.getClassLoader());
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}
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public Class<?> define(String name, byte[] data)
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{
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return defineClass(name, data, 0, data.length);
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}
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}
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}
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