Paper-Old/patches/server/0287-Async-command-map-building.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Callahan <mr.callahhh@gmail.com>
Date: Wed, 8 Apr 2020 02:42:14 -0500
Subject: [PATCH] Async command map building

This adds a custom pool inorder to make sure that they are closed
without much though, as it doesn't matter if the client is not sent
commands if the server is restarting. Using the default async pool caused issues to arise
due to the shutdown logic generally being much later.

diff --git a/src/main/java/net/minecraft/commands/Commands.java b/src/main/java/net/minecraft/commands/Commands.java
index 5a1accff1a7dc2ab40224ec0952a287cd6099aee..2b722091920116ded43ff54c413d4dd47da65ed4 100644
--- a/src/main/java/net/minecraft/commands/Commands.java
+++ b/src/main/java/net/minecraft/commands/Commands.java
@@ -458,6 +458,24 @@ public class Commands {
         if ( org.spigotmc.SpigotConfig.tabComplete < 0 ) return; // Spigot
         // CraftBukkit start
         // Register Vanilla commands into builtRoot as before
+        // Paper start - Perf: Async command map building
+        COMMAND_SENDING_POOL.execute(() -> {
+                this.sendAsync(player);
+        });
+    }
+
+    public static final java.util.concurrent.ThreadPoolExecutor COMMAND_SENDING_POOL = new java.util.concurrent.ThreadPoolExecutor(
+        0, 2, 60L, java.util.concurrent.TimeUnit.SECONDS,
+        new java.util.concurrent.LinkedBlockingQueue<>(),
+        new com.google.common.util.concurrent.ThreadFactoryBuilder()
+            .setNameFormat("Paper Async Command Builder Thread Pool - %1$d")
+            .setUncaughtExceptionHandler(new net.minecraft.DefaultUncaughtExceptionHandlerWithName(net.minecraft.server.MinecraftServer.LOGGER))
+            .build(),
+        new java.util.concurrent.ThreadPoolExecutor.DiscardPolicy()
+    );
+
+    private void sendAsync(ServerPlayer player) {
+        // Paper end - Perf: Async command map building
         Map<CommandNode<CommandSourceStack>, CommandNode<SharedSuggestionProvider>> map = Maps.newIdentityHashMap(); // Use identity to prevent aliasing issues
         RootCommandNode vanillaRoot = new RootCommandNode();
 
@@ -475,7 +493,14 @@ public class Commands {
         for (CommandNode node : rootcommandnode.getChildren()) {
             bukkit.add(node.getName());
         }
+        // Paper start - Perf: Async command map building
+        net.minecraft.server.MinecraftServer.getServer().execute(() -> {
+           runSync(player, bukkit, rootcommandnode);
+        });
+    }
 
+    private void runSync(ServerPlayer player, Collection<String> bukkit, RootCommandNode<SharedSuggestionProvider> rootcommandnode) {
+        // Paper end - Perf: Async command map building
         PlayerCommandSendEvent event = new PlayerCommandSendEvent(player.getBukkitEntity(), new LinkedHashSet<>(bukkit));
         event.getPlayer().getServer().getPluginManager().callEvent(event);
 
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index e6b029c8ee05c5e045a7d694a9e8616d6a1ea484..5f377267cc3c72e4d55c29f20ce3cd3eed0e5258 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -926,6 +926,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
         }
 
         MinecraftServer.LOGGER.info("Stopping server");
+        Commands.COMMAND_SENDING_POOL.shutdownNow(); // Paper - Perf: Async command map building; Shutdown and don't bother finishing
         MinecraftTimings.stopServer(); // Paper
         // CraftBukkit start
         if (this.server != null) {