From 64855ea7893dfa03167b3a6019050b312109cc7b Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 26 Nov 2017 13:19:58 -0500
Subject: [PATCH] AsyncTabCompleteEvent

Let plugins be able to control tab completion of commands and chat async.

This will be useful for frameworks like ACF so we can define async safe completion handlers,
and avoid going to main for tab completions.

Especially useful if you need to query a database in order to obtain the results for tab
completion, such as offline players.

Also adds isCommand and getLocation to the sync TabCompleteEvent

diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
index 167e386c8..3fbf51e52 100644
--- a/src/main/java/net/minecraft/server/PlayerConnection.java
+++ b/src/main/java/net/minecraft/server/PlayerConnection.java
@@ -2276,24 +2276,51 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {
         // CraftBukkit end
     }
 
-    public void a(PacketPlayInTabComplete packetplayintabcomplete) {
-        PlayerConnectionUtils.ensureMainThread(packetplayintabcomplete, this, this.player.x());
+    // Paper start - async tab completion
+    public void a(PacketPlayInTabComplete packet) {
         // CraftBukkit start
         if (chatSpamField.addAndGet(this, 10) > 500 && !this.minecraftServer.getPlayerList().isOp(this.player.getProfile())) {
-            this.disconnect(new ChatMessage("disconnect.spam", new Object[0]));
+            minecraftServer.postToMainThread(() -> this.disconnect(new ChatMessage("disconnect.spam", new Object[0])));
             return;
         }
         // CraftBukkit end
-        ArrayList arraylist = Lists.newArrayList();
-        Iterator iterator = this.minecraftServer.tabCompleteCommand(this.player, packetplayintabcomplete.a(), packetplayintabcomplete.b(), packetplayintabcomplete.c()).iterator();
 
-        while (iterator.hasNext()) {
-            String s = (String) iterator.next();
+        com.destroystokyo.paper.event.server.AsyncTabCompleteEvent event;
+        java.util.List<String> completions = new ArrayList<>();
+        BlockPosition blockpos = packet.b();
+        String buffer = packet.a();
+        boolean isCommand = buffer.startsWith("/") || packet.c();
+        event = new com.destroystokyo.paper.event.server.AsyncTabCompleteEvent(this.getPlayer(), completions,
+            buffer, isCommand, blockpos != null ? MCUtil.toLocation(player.world, blockpos) : null);
+        event.callEvent();
+        completions = event.isCancelled() ? com.google.common.collect.ImmutableList.of() : event.getCompletions();
+        if (event.isCancelled() || event.isHandled()) {
+            // Still fire sync event with the provided completions, if someone is listening
+            if (!event.isCancelled() && org.bukkit.event.server.TabCompleteEvent.getHandlerList().getRegisteredListeners().length > 0) {
+                java.util.List<String> finalCompletions = completions;
+                Waitable<java.util.List<String>> syncCompletions = new Waitable<java.util.List<String>>() {
+                    @Override
+                    protected java.util.List<String> evaluate() {
+                        org.bukkit.event.server.TabCompleteEvent syncEvent = new org.bukkit.event.server.TabCompleteEvent(PlayerConnection.this.getPlayer(), buffer, finalCompletions, isCommand, blockpos != null ? MCUtil.toLocation(player.world, blockpos) : null);
+                        return syncEvent.callEvent() ? syncEvent.getCompletions() : com.google.common.collect.ImmutableList.of();
+                    }
+                };
+                server.getServer().processQueue.add(syncCompletions);
+                try {
+                    completions = syncCompletions.get();
+                } catch (InterruptedException | ExecutionException e1) {
+                    e1.printStackTrace();
+                }
+            }
 
-            arraylist.add(s);
+            this.player.playerConnection.sendPacket(new PacketPlayOutTabComplete(completions.toArray(new String[completions.size()])));
+            return;
         }
-
-        this.player.playerConnection.sendPacket(new PacketPlayOutTabComplete((String[]) arraylist.toArray(new String[arraylist.size()])));
+        minecraftServer.postToMainThread(() -> {
+            java.util.List<String> syncCompletions = this.minecraftServer.tabCompleteCommand(this.player, buffer, blockpos, isCommand);
+            this.player.playerConnection.sendPacket(new PacketPlayOutTabComplete(syncCompletions.toArray(new String[syncCompletions.size()])));
+        });
+        // Paper end
     }
 
     public void a(PacketPlayInSettings packetplayinsettings) {
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index aca5ea7c0..090a4d2f2 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -1643,8 +1643,8 @@ public final class CraftServer implements Server {
         } else {
             offers = tabCompleteChat(player, message);
         }
-
-        TabCompleteEvent tabEvent = new TabCompleteEvent(player, message, offers);
+        
+        TabCompleteEvent tabEvent = new TabCompleteEvent(player, message, offers, message.startsWith("/") || forceCommand, pos != null ? MCUtil.toLocation(((CraftWorld) player.getWorld()).getHandle(), pos) : null); // Paper
         getPluginManager().callEvent(tabEvent);
 
         return tabEvent.isCancelled() ? Collections.EMPTY_LIST : tabEvent.getCompletions();
diff --git a/src/main/java/org/bukkit/craftbukkit/command/ConsoleCommandCompleter.java b/src/main/java/org/bukkit/craftbukkit/command/ConsoleCommandCompleter.java
index 1e3aae3b8..95d13c146 100644
--- a/src/main/java/org/bukkit/craftbukkit/command/ConsoleCommandCompleter.java
+++ b/src/main/java/org/bukkit/craftbukkit/command/ConsoleCommandCompleter.java
@@ -28,6 +28,39 @@ public class ConsoleCommandCompleter implements Completer {
     public void complete(LineReader reader, ParsedLine line, List<Candidate> candidates) {
         final CraftServer server = this.server.server;
         final String buffer = line.line();
+        // Async Tab Complete
+        com.destroystokyo.paper.event.server.AsyncTabCompleteEvent event;
+        java.util.List<String> completions = new java.util.ArrayList<>();
+        event = new com.destroystokyo.paper.event.server.AsyncTabCompleteEvent(server.getConsoleSender(), completions,
+            buffer, true, null);
+        event.callEvent();
+        completions = event.isCancelled() ? com.google.common.collect.ImmutableList.of() : event.getCompletions();
+
+        if (event.isCancelled() || event.isHandled()) {
+            // Still fire sync event with the provided completions, if someone is listening
+            if (!event.isCancelled() && TabCompleteEvent.getHandlerList().getRegisteredListeners().length > 0) {
+                List<String> finalCompletions = completions;
+                Waitable<List<String>> syncCompletions = new Waitable<List<String>>() {
+                    @Override
+                    protected List<String> evaluate() {
+                        org.bukkit.event.server.TabCompleteEvent syncEvent = new org.bukkit.event.server.TabCompleteEvent(server.getConsoleSender(), buffer, finalCompletions);
+                        return syncEvent.callEvent() ? syncEvent.getCompletions() : com.google.common.collect.ImmutableList.of();
+                    }
+                };
+                server.getServer().processQueue.add(syncCompletions);
+                try {
+                    completions = syncCompletions.get();
+                } catch (InterruptedException | ExecutionException e1) {
+                    e1.printStackTrace();
+                }
+            }
+
+            if (!completions.isEmpty()) {
+                candidates.addAll(completions.stream().map(Candidate::new).collect(java.util.stream.Collectors.toList()));
+            }
+            return;
+        }
+
         // Paper end
         Waitable<List<String>> waitable = new Waitable<List<String>>() {
             @Override
-- 
2.16.2