From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <git@steinborn.me>
Date: Sun, 5 Jul 2020 22:38:18 -0400
Subject: [PATCH] Optimize NetworkManager Exception Handling


diff --git a/src/main/java/net/minecraft/network/ConnectionProtocol.java b/src/main/java/net/minecraft/network/ConnectionProtocol.java
index 9d6dafb4855af9ccb7bc033ebf0fca5f75ceb9c6..347c4eff66ec1f3393494133ca59df2411dafa21 100644
--- a/src/main/java/net/minecraft/network/ConnectionProtocol.java
+++ b/src/main/java/net/minecraft/network/ConnectionProtocol.java
@@ -590,6 +590,7 @@ public enum ConnectionProtocol {
 
         @Nullable
         public Packet<?> createPacket(int id, FriendlyByteBuf buf) {
+            if (id < 0 || id >= this.idToDeserializer.size()) return null; // Paper - Perf: Optimize exception handling
             Function<FriendlyByteBuf, ? extends Packet<? super T>> function = this.idToDeserializer.get(id);
             return (Packet<?>)(function != null ? function.apply(buf) : null);
         }
diff --git a/src/main/java/net/minecraft/network/Varint21FrameDecoder.java b/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
index 421dd76816063d56ea80339b77531729edd6aa55..1523d69b7b332f0085f40310a94d406da6513edc 100644
--- a/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
+++ b/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
@@ -39,6 +39,12 @@ public class Varint21FrameDecoder extends ByteToMessageDecoder {
     }
 
     protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) {
+        // Paper start - Perf: Optimize exception handling; if channel is not active just discard the packet
+        if (!channelHandlerContext.channel().isActive()) {
+            byteBuf.skipBytes(byteBuf.readableBytes());
+            return;
+        }
+        // Paper end - Perf: Optimize exception handling
         byteBuf.markReaderIndex();
         this.helperBuf.clear();
         if (!copyVarint(byteBuf, this.helperBuf)) {