Paper/patches/server/0408-Optimize-NetworkManager-Exception-Handling.patch

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 ac1aa37329bd4d411964ea34ea8147f6db945b9a..0ed8d5691a5562a944b68f385b97ef814c2380e1 100644
--- a/src/main/java/net/minecraft/network/ConnectionProtocol.java
+++ b/src/main/java/net/minecraft/network/ConnectionProtocol.java
@@ -341,6 +341,7 @@ 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 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 00c170a16a57f41f881c6b282cba474ce485b34c..137b9a088c82ce6813bf8a80468675bb4992ce53 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)) {