package cpw.mods.fml.common.eventhandler;
import static org.objectweb.asm.Opcodes.*;
import java.lang.reflect.Method;
import java.util.HashMap;
import org.apache.logging.log4j.ThreadContext;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Type;
import com.google.common.collect.Maps;
import cpw.mods.fml.common.ModContainer;
public class ASMEventHandler implements IEventListener
{
private static int IDs = 0;
private static final String HANDLER_DESC = Type.getInternalName(IEventListener.class);
private static final String HANDLER_FUNC_DESC = Type.getMethodDescriptor(IEventListener.class.getDeclaredMethods()[0]);
private static final ASMClassLoader LOADER = new ASMClassLoader();
private static final HashMap<Method, Class<?>> cache = Maps.newHashMap();
private static final boolean GETCONTEXT = Boolean.parseBoolean(System.getProperty("fml.LogContext", "false"));
private final IEventListener handler;
private final SubscribeEvent subInfo;
private ModContainer owner;
private String readable;
public ASMEventHandler(Object target, Method method, ModContainer owner) throws Exception
{
this.owner = owner;
handler = (IEventListener)createWrapper(method).getConstructor(Object.class).newInstance(target);
subInfo = method.getAnnotation(SubscribeEvent.class);
readable = "ASM: " + target + " " + method.getName() + Type.getMethodDescriptor(method);
}
@Override
public void invoke(Event event)
{
if (owner != null && GETCONTEXT)
{
ThreadContext.put("mod", owner.getName());
}
else if (GETCONTEXT)
{
ThreadContext.put("mod", "");
}
if (handler != null)
{
if (!event.isCancelable() || !event.isCanceled() || subInfo.receiveCanceled())
{
handler.invoke(event);
}
}
if (GETCONTEXT)
ThreadContext.remove("mod");
}
public EventPriority getPriority()
{
return subInfo.priority();
}
public Class<?> createWrapper(Method callback)
{
if (cache.containsKey(callback))
{
return cache.get(callback);
}
ClassWriter cw = new ClassWriter(0);
MethodVisitor mv;
String name = getUniqueName(callback);
String desc = name.replace('.', '/');
String instType = Type.getInternalName(callback.getDeclaringClass());
String eventType = Type.getInternalName(callback.getParameterTypes()[0]);
/*
System.out.println("Name: " + name);
System.out.println("Desc: " + desc);
System.out.println("InstType: " + instType);
System.out.println("Callback: " + callback.getName() + Type.getMethodDescriptor(callback));
System.out.println("Event: " + eventType);
*/
cw.visit(V1_6, ACC_PUBLIC | ACC_SUPER, desc, null, "java/lang/Object", new String[]{ HANDLER_DESC });
cw.visitSource(".dynamic", null);
{
cw.visitField(ACC_PUBLIC, "instance", "Ljava/lang/Object;", null, null).visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC, "<init>", "(Ljava/lang/Object;)V", null, null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 1);
mv.visitFieldInsn(PUTFIELD, desc, "instance", "Ljava/lang/Object;");
mv.visitInsn(RETURN);
mv.visitMaxs(2, 2);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC, "invoke", HANDLER_FUNC_DESC, null, null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, desc, "instance", "Ljava/lang/Object;");
mv.visitTypeInsn(CHECKCAST, instType);
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, eventType);
mv.visitMethodInsn(INVOKEVIRTUAL, instType, callback.getName(), Type.getMethodDescriptor(callback), false);
mv.visitInsn(RETURN);
mv.visitMaxs(2, 2);
mv.visitEnd();
}
cw.visitEnd();
Class<?> ret = LOADER.define(name, cw.toByteArray());
cache.put(callback, ret);
return ret;
}
private String getUniqueName(Method callback)
{
return String.format("%s_%d_%s_%s_%s", getClass().getName(), IDs++,
callback.getDeclaringClass().getSimpleName(),
callback.getName(),
callback.getParameterTypes()[0].getSimpleName());
}
private static class ASMClassLoader extends ClassLoader
{
private ASMClassLoader()
{
super(ASMClassLoader.class.getClassLoader());
}
public Class<?> define(String name, byte[] data)
{
return defineClass(name, data, 0, data.length);
}
}
public String toString()
{
return readable;
}
}