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


diff --git a/src/main/java/net/minecraft/commands/Commands.java b/src/main/java/net/minecraft/commands/Commands.java
index 7ca6a1a3f10cb19d759f6d4dc9d5458ac0fc05d3..13e358e0eac3bfd426d924b6f745e001df76c64a 100644
--- a/src/main/java/net/minecraft/commands/Commands.java
+++ b/src/main/java/net/minecraft/commands/Commands.java
@@ -29,6 +29,7 @@ import net.minecraft.network.chat.MutableComponent;
 import net.minecraft.network.chat.TextComponent;
 import net.minecraft.network.chat.TranslatableComponent;
 import net.minecraft.network.protocol.game.ClientboundCommandsPacket;
+import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.commands.AdvancementCommands;
 import net.minecraft.server.commands.AttributeCommand;
 import net.minecraft.server.commands.BanIpCommands;
@@ -335,25 +336,40 @@ public class Commands {
         if ( org.spigotmc.SpigotConfig.tabComplete < 0 ) return; // Spigot
         // CraftBukkit start
         // Register Vanilla commands into builtRoot as before
+        // Paper start - Async command map building
+        java.util.concurrent.ForkJoinPool.commonPool().execute(() -> {
+            sendAsync(player);
+        });
+    }
+
+    private void sendAsync(ServerPlayer entityplayer) {
+        // Paper end - Async command map building
         Map<CommandNode<CommandSourceStack>, CommandNode<SharedSuggestionProvider>> map = Maps.newIdentityHashMap(); // Use identity to prevent aliasing issues
         RootCommandNode vanillaRoot = new RootCommandNode();
 
-        RootCommandNode<CommandSourceStack> vanilla = player.server.vanillaCommandDispatcher.getDispatcher().getRoot();
+        RootCommandNode<CommandSourceStack> vanilla = entityplayer.server.vanillaCommandDispatcher.getDispatcher().getRoot();
         map.put(vanilla, vanillaRoot);
-        this.fillUsableCommands(vanilla, vanillaRoot, player.createCommandSourceStack(), (Map) map);
+        this.fillUsableCommands(vanilla, vanillaRoot, entityplayer.createCommandSourceStack(), (Map) map);
 
         // Now build the global commands in a second pass
         RootCommandNode<SharedSuggestionProvider> rootcommandnode = new RootCommandNode();
 
         map.put(this.dispatcher.getRoot(), rootcommandnode);
-        this.fillUsableCommands(this.dispatcher.getRoot(), rootcommandnode, player.createCommandSourceStack(), (Map) map);
+        this.fillUsableCommands(this.dispatcher.getRoot(), rootcommandnode, entityplayer.createCommandSourceStack(), (Map) map);
 
         Collection<String> bukkit = new LinkedHashSet<>();
         for (CommandNode node : rootcommandnode.getChildren()) {
             bukkit.add(node.getName());
         }
+        // Paper start - Async command map building
+        MinecraftServer.getServer().execute(() -> {
+           runSync(entityplayer, bukkit, rootcommandnode);
+        });
+    }
 
-        PlayerCommandSendEvent event = new PlayerCommandSendEvent(player.getBukkitEntity(), new LinkedHashSet<>(bukkit));
+    private void runSync(ServerPlayer entityplayer, Collection<String> bukkit, RootCommandNode<SharedSuggestionProvider> rootcommandnode) {
+        // Paper end - Async command map building
+        PlayerCommandSendEvent event = new PlayerCommandSendEvent(entityplayer.getBukkitEntity(), new LinkedHashSet<>(bukkit));
         event.getPlayer().getServer().getPluginManager().callEvent(event);
 
         // Remove labels that were removed during the event
@@ -363,7 +379,7 @@ public class Commands {
             }
         }
         // CraftBukkit end
-        player.connection.send(new ClientboundCommandsPacket(rootcommandnode));
+        entityplayer.connection.send(new ClientboundCommandsPacket(rootcommandnode));
     }
 
     private void fillUsableCommands(CommandNode<CommandSourceStack> tree, CommandNode<SharedSuggestionProvider> result, CommandSourceStack source, Map<CommandNode<CommandSourceStack>, CommandNode<SharedSuggestionProvider>> resultNodes) {