From 558411692a5995c91687ea6ca90cc9a26ada60ca Mon Sep 17 00:00:00 2001
From: Travis Watkins <amaranth@ubuntu.com>
Date: Sat, 17 Nov 2012 11:48:22 -0600
Subject: [PATCH] Don't wait for main thread when processing commands.

In order to correctly handle disconnects for invalid chat we setup a
Waitable and pass it to the main thread then wait for it to be processed.
However, commands are also chat packets and they are already on the main
thread. In this case, waiting will deadlock the server so we should just
do a normal disconnect.
---
 .../minecraft/server/NetServerHandler.java    | 102 ++++++++++--------
 1 file changed, 57 insertions(+), 45 deletions(-)

diff --git a/src/main/java/net/minecraft/server/NetServerHandler.java b/src/main/java/net/minecraft/server/NetServerHandler.java
index 831ad7ed40..a6e6403107 100644
--- a/src/main/java/net/minecraft/server/NetServerHandler.java
+++ b/src/main/java/net/minecraft/server/NetServerHandler.java
@@ -794,22 +794,26 @@ public class NetServerHandler extends NetHandler {
 
             if (s.length() > 100) {
                 // CraftBukkit start
-                Waitable waitable = new Waitable() {
-                    @Override
-                    protected Object evaluate() {
-                        NetServerHandler.this.disconnect("Chat message too long");
-                        return null;
+                if (packet3chat.a_()) {
+                    Waitable waitable = new Waitable() {
+                        @Override
+                        protected Object evaluate() {
+                            NetServerHandler.this.disconnect("Chat message too long");
+                            return null;
+                        }
+                    };
+
+                    this.minecraftServer.processQueue.add(waitable);
+
+                    try {
+                        waitable.get();
+                    } catch (InterruptedException e) {
+                        Thread.currentThread().interrupt();
+                    } catch (ExecutionException e) {
+                        throw new RuntimeException(e);
                     }
-                };
-
-                this.minecraftServer.processQueue.add(waitable);
-
-                try {
-                    waitable.get();
-                } catch (InterruptedException e) {
-                    Thread.currentThread().interrupt();
-                } catch (ExecutionException e) {
-                    throw new RuntimeException(e);
+                } else {
+                    this.disconnect("Chat message too long");
                 }
                 // CraftBukkit end
             } else {
@@ -818,22 +822,26 @@ public class NetServerHandler extends NetHandler {
                 for (int i = 0; i < s.length(); ++i) {
                     if (!SharedConstants.isAllowedChatCharacter(s.charAt(i))) {
                         // CraftBukkit start
-                        Waitable waitable = new Waitable() {
-                            @Override
-                            protected Object evaluate() {
-                                NetServerHandler.this.disconnect("Illegal characters in chat");
-                                return null;
+                        if (packet3chat.a_()) {
+                            Waitable waitable = new Waitable() {
+                                @Override
+                                protected Object evaluate() {
+                                    NetServerHandler.this.disconnect("Illegal characters in chat");
+                                    return null;
+                                }
+                            };
+
+                            this.minecraftServer.processQueue.add(waitable);
+
+                            try {
+                                waitable.get();
+                            } catch (InterruptedException e) {
+                                Thread.currentThread().interrupt();
+                            } catch (ExecutionException e) {
+                                throw new RuntimeException(e);
                             }
-                        };
-
-                        this.minecraftServer.processQueue.add(waitable);
-
-                        try {
-                            waitable.get();
-                        } catch (InterruptedException e) {
-                            Thread.currentThread().interrupt();
-                        } catch (ExecutionException e) {
-                            throw new RuntimeException(e);
+                        } else {
+                            this.disconnect("Illegal characters in chat");
                         }
                         // CraftBukkit end
                         return;
@@ -851,22 +859,26 @@ public class NetServerHandler extends NetHandler {
                 // This section stays because it is only applicable to packets
                 if (chatSpamField.addAndGet(this, 20) > 200 && !this.minecraftServer.getServerConfigurationManager().isOp(this.player.name)) { // CraftBukkit use thread-safe spam
                     // CraftBukkit start
-                    Waitable waitable = new Waitable() {
-                        @Override
-                        protected Object evaluate() {
-                            NetServerHandler.this.disconnect("disconnect.spam");
-                            return null;
+                    if (packet3chat.a_()) {
+                        Waitable waitable = new Waitable() {
+                            @Override
+                            protected Object evaluate() {
+                                NetServerHandler.this.disconnect("disconnect.spam");
+                                return null;
+                            }
+                        };
+
+                        this.minecraftServer.processQueue.add(waitable);
+
+                        try {
+                            waitable.get();
+                        } catch (InterruptedException e) {
+                            Thread.currentThread().interrupt();
+                        } catch (ExecutionException e) {
+                            throw new RuntimeException(e);
                         }
-                    };
-
-                    this.minecraftServer.processQueue.add(waitable);
-
-                    try {
-                        waitable.get();
-                    } catch (InterruptedException e) {
-                        Thread.currentThread().interrupt();
-                    } catch (ExecutionException e) {
-                        throw new RuntimeException(e);
+                    } else {
+                        this.disconnect("disconnect.spam");
                     }
                     // CraftBukkit end
                 }