Invert the actual packet instance instead of a new instance.

In NetworkFieldInjector, we use a "inverted" packet class to undo the 
data received counter when a packet has been cancelled. 

Previously, we would generate a proxy class that inherits from the 
class of the packet (Packet3Chat, etc.) along with its size() method 
(which is called and added to the counter, cancelling the other packet),
but this doesn't work for packets that are dynamically sized such as
Packet255KickDisconnect. Instead, we now pass the actual instance to
 the proxy class through a weak hash map.

ProtocolLib/src/main/java/com/comphenix/protocol/injector/ListenerInvoker.java

@@ -52,8 +52,9 @@ public interface ListenerInvoker {
 	public abstract void unregisterPacketClass(Class<?> clazz);
 
 	/**
-	 * Remove a given class from the packet registry. Internal method.
-	 * @param clazz - class to remove.
+	 * Register a given class in the packet registry. Internal method.
+	 * @param clazz - class to register.
+	 * @param packetID - the the new associated packet ID.
 	 */
 	public abstract void registerPacketClass(Class<?> clazz, int packetID);
 

ProtocolLib/src/main/java/com/comphenix/protocol/injector/player/InjectedArrayList.java

@@ -21,12 +21,16 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Set;
+import java.util.concurrent.ConcurrentMap;
 
+import com.comphenix.protocol.Packets;
 import com.comphenix.protocol.ProtocolLibrary;
 import com.comphenix.protocol.error.Report;
 import com.comphenix.protocol.error.ReportType;
 import com.comphenix.protocol.injector.ListenerInvoker;
 import com.comphenix.protocol.injector.player.NetworkFieldInjector.FakePacket;
+import com.comphenix.protocol.utility.MinecraftReflection;
+import com.google.common.collect.MapMaker;
 
 import net.sf.cglib.proxy.Callback;
 import net.sf.cglib.proxy.Enhancer;
@@ -46,6 +50,9 @@ class InjectedArrayList extends ArrayList<Object> {
 	 */
 	private static final long serialVersionUID = -1173865905404280990L;
 	
+	// Fake inverted proxy objects
+	private static ConcurrentMap<Object, Object> delegateLookup = new MapMaker().weakKeys().makeMap();
+	
 	private transient PlayerInjector injector;
 	private transient Set<Object> ignoredPackets;
 	private transient ClassLoader classLoader;
@@ -108,9 +115,6 @@ class InjectedArrayList extends ArrayList<Object> {
 		ListenerInvoker invoker = injector.getInvoker();
 		
 		int packetID = invoker.getPacketID(source);
-		Class<?> type = invoker.getPacketClassFromID(packetID, true);
-
-		System.out.println(type.getName());
 
 		// We want to subtract the byte amount that were added to the running
 		// total of outstanding packets. Otherwise, cancelling too many packets
@@ -131,7 +135,7 @@ class InjectedArrayList extends ArrayList<Object> {
 		//   ect.
 		//   }
 		Enhancer ex = new Enhancer();
-		ex.setSuperclass(type);
+		ex.setSuperclass(MinecraftReflection.getPacketClass());
 		ex.setInterfaces(new Class[] { FakePacket.class } );
 		ex.setUseCache(true);
 		ex.setClassLoader(classLoader);
@@ -143,7 +147,10 @@ class InjectedArrayList extends ArrayList<Object> {
 		try {
 			// Temporarily associate the fake packet class
 			invoker.registerPacketClass(proxyClass, packetID);
-			return proxyClass.newInstance();
+			Object proxy = proxyClass.newInstance();
+			
+			InjectedArrayList.registerDelegate(proxy, source);
+			return proxy;
 			
 		} catch (Exception e) {
 			// Don't pollute the throws tree
@@ -154,6 +161,15 @@ class InjectedArrayList extends ArrayList<Object> {
 		}
 	}
 	
+	/**
+	 * Ensure that the inverted integer proxy uses the given object as source.
+	 * @param proxy - inverted integer proxy.
+	 * @param source - source object.
+	 */
+	private static void registerDelegate(Object proxy, Object source) {
+		delegateLookup.put(proxy, source);
+	}
+	
 	/**
 	 * Inverts the integer result of every integer method.
 	 * @author Kristian
@@ -161,11 +177,17 @@ class InjectedArrayList extends ArrayList<Object> {
 	private class InvertedIntegerCallback implements MethodInterceptor {		
 		@Override
 		public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
+			final Object delegate = delegateLookup.get(obj);
+			
+			if (delegate == null) {
+				throw new IllegalStateException("Unable to find delegate source for " + obj);
+			}
+				
 			if (method.getReturnType().equals(int.class) && args.length == 0) {
-				Integer result = (Integer) proxy.invokeSuper(obj, args);
+				Integer result = (Integer) proxy.invoke(delegate, args);
 				return -result;
 			} else {
-				return proxy.invokeSuper(obj, args);
+				return proxy.invoke(delegate, args);
 			}
 		}
 	}