Asynchronously filter commands on Paper when possible

Essentials/src/main/java/com/earth2me/essentials/EssentialsPlayerListener.java

@@ -13,6 +13,8 @@
 import io.papermc.lib.PaperLib;
 import net.ess3.api.IEssentials;
 import net.ess3.api.events.AfkStatusChangeEvent;
+import net.ess3.provider.CommandSendListenerProvider;
+import net.ess3.provider.providers.PaperCommandSendListenerProvider;
 import net.essentialsx.api.v2.events.AsyncUserDataLoadEvent;
 import org.bukkit.BanEntry;
 import org.bukkit.BanList;
@@ -37,7 +39,6 @@
 import org.bukkit.event.player.PlayerBucketEmptyEvent;
 import org.bukkit.event.player.PlayerChangedWorldEvent;
 import org.bukkit.event.player.PlayerCommandPreprocessEvent;
-import org.bukkit.event.player.PlayerCommandSendEvent;
 import org.bukkit.event.player.PlayerEggThrowEvent;
 import org.bukkit.event.player.PlayerFishEvent;
 import org.bukkit.event.player.PlayerInteractEvent;
@@ -66,6 +67,7 @@
 import java.util.Locale;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.function.Predicate;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
@@ -98,6 +100,15 @@ private static boolean isCommandSendEvent() {
         }
     }
 
+    private static boolean isPaperCommandSendEvent() {
+        try {
+            Class.forName("com.destroystokyo.paper.event.brigadier.AsyncPlayerSendCommandsEvent");
+            return true;
+        } catch (final ClassNotFoundException ignored) {
+            return false;
+        }
+    }
+
     private static boolean isArrowPickupEvent() {
         try {
             Class.forName("org.bukkit.event.player.PlayerPickupArrowEvent");
@@ -120,8 +131,10 @@ public void registerEvents() {
             ess.getServer().getPluginManager().registerEvents(new PickupListenerPre1_12(), ess);
         }
 
-        if (isCommandSendEvent()) {
-            ess.getServer().getPluginManager().registerEvents(new CommandSendListener(), ess);
+        if (isPaperCommandSendEvent()) {
+            ess.getServer().getPluginManager().registerEvents(new PaperCommandSendListenerProvider(new CommandSendFilter()), ess);
+        } else if (isCommandSendEvent()) {
+            ess.getServer().getPluginManager().registerEvents(new PaperCommandSendListenerProvider(new CommandSendFilter()), ess);
         }
     }
 
@@ -960,15 +973,14 @@ public void onPlayerPickupItem(final org.bukkit.event.entity.EntityPickupItemEve
         }
     }
 
-    private final class CommandSendListener implements Listener {
-        @EventHandler(priority = EventPriority.NORMAL)
-        public void onCommandSend(final PlayerCommandSendEvent event) {
-            final User user = ess.getUser(event.getPlayer());
-
+    private final class CommandSendFilter implements CommandSendListenerProvider.Filter {
+        @Override
+        public Predicate<String> apply(Player player) {
+            final User user = ess.getUser(player);
             final Set<PluginCommand> checked = new HashSet<>();
             final Set<PluginCommand> toRemove = new HashSet<>();
 
-            event.getCommands().removeIf(label -> {
+            return label -> {
                 if (isEssentialsCommand(label)) {
                     final PluginCommand command = ess.getServer().getPluginCommand(label);
                     if (!checked.contains(command)) {
@@ -980,25 +992,21 @@ public void onCommandSend(final PlayerCommandSendEvent event) {
                     return toRemove.contains(command);
                 }
                 return false;
-            });
-
-            if (ess.getSettings().isDebug()) {
-                ess.getLogger().info("Removed commands: " + toRemove.toString());
-            }
+            };
         }
 
         /**
          * Returns true if all of the following are true:
          * - The command is a plugin command
-         * - The plugin command is from a plugin in an essentials-controlled package
+         * - The plugin command is from an official EssentialsX plugin or addon
          * - There is no known alternative OR the alternative is overridden by Essentials
          */
         private boolean isEssentialsCommand(final String label) {
             final PluginCommand command = ess.getServer().getPluginCommand(label);
 
             return command != null
-                && (command.getPlugin() == ess || command.getPlugin().getClass().getName().startsWith("com.earth2me.essentials"))
-                && (ess.getSettings().isCommandOverridden(label) || (ess.getAlternativeCommandsHandler().getAlternative(label) == null));
+                    && (command.getPlugin() == ess || command.getPlugin().getClass().getName().startsWith("com.earth2me.essentials") || command.getPlugin().getClass().getName().startsWith("net.essentialsx"))
+                    && (ess.getSettings().isCommandOverridden(label) || (ess.getAlternativeCommandsHandler().getAlternative(label) == null));
         }
     }
 }

providers/BaseProviders/src/main/java/net/ess3/provider/CommandSendListenerProvider.java

@@ -0,0 +1,30 @@
+package net.ess3.provider;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.Listener;
+
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+/**
+ * A provider for 1.13+ command send listeners.
+ * <p>
+ * Note to maintainers: this doesn't extend {@link ProviderListener} because it doesn't make sense here.
+ */
+public abstract class CommandSendListenerProvider implements Provider, Listener {
+    private final Filter commandFilter;
+
+    protected CommandSendListenerProvider(Filter commandFilter) {
+        this.commandFilter = commandFilter;
+    }
+
+    protected final Predicate<String> filter(final Player player) {
+        return commandFilter.apply(player);
+    }
+
+    /**
+     * A function that returns a predicate to test whether commands should be hidden from the given player.
+     */
+    public interface Filter extends Function<Player, Predicate<String>> {
+    }
+}

providers/BaseProviders/src/main/java/net/ess3/provider/providers/BukkitCommandSendListenerProvider.java

@@ -0,0 +1,25 @@
+package net.ess3.provider.providers;
+
+import net.ess3.provider.CommandSendListenerProvider;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.player.PlayerCommandSendEvent;
+
+import java.util.function.Predicate;
+
+public class BukkitCommandSendListenerProvider extends CommandSendListenerProvider {
+    public BukkitCommandSendListenerProvider(Filter commandFilter) {
+        super(commandFilter);
+    }
+
+    @EventHandler(priority = EventPriority.NORMAL)
+    public void onCommandSend(PlayerCommandSendEvent event) {
+        final Predicate<String> filter = filter(event.getPlayer());
+        event.getCommands().removeIf(filter);
+    }
+
+    @Override
+    public String getDescription() {
+        return "Bukkit synchronous command send listener";
+    }
+}

providers/PaperProvider/build.gradle

@@ -5,6 +5,7 @@ plugins {
 dependencies {
     implementation project(':providers:BaseProviders')
     compileOnly 'com.destroystokyo.paper:paper-api:1.16.5-R0.1-SNAPSHOT'
+    compileOnly 'com.destroystokyo.paper:paper-mojangapi:1.16.5-R0.1-SNAPSHOT'
 }
 
 essentials {

providers/PaperProvider/src/main/java/net/ess3/provider/providers/PaperCommandSendListenerProvider.java

@@ -0,0 +1,35 @@
+package net.ess3.provider.providers;
+
+import com.destroystokyo.paper.event.brigadier.AsyncPlayerSendCommandsEvent;
+import com.mojang.brigadier.tree.CommandNode;
+import net.ess3.provider.CommandSendListenerProvider;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+
+import java.util.Collection;
+import java.util.function.Predicate;
+
+public class PaperCommandSendListenerProvider extends CommandSendListenerProvider {
+
+    public PaperCommandSendListenerProvider(Filter commandFilter) {
+        super(commandFilter);
+    }
+
+    @EventHandler(priority = EventPriority.NORMAL)
+    public void onAsyncCommandSend(@SuppressWarnings("deprecation") AsyncPlayerSendCommandsEvent<?> event) {
+        if (!event.isAsynchronous() && event.hasFiredAsync()) {
+            // this has already fired once async
+            return;
+        }
+
+        final Collection<? extends CommandNode<?>> children = event.getCommandNode().getChildren();
+        final Predicate<String> filter = filter(event.getPlayer());
+
+        children.removeIf(node -> filter.test(node.getName()));
+    }
+
+    @Override
+    public String getDescription() {
+        return "Paper async Brigadier command send listener";
+    }
+}

settings.gradle.kts

@@ -14,6 +14,9 @@ dependencyResolutionManagement {
         maven("https://repo.extendedclip.com/content/repositories/placeholderapi/") {
             content { includeGroup("me.clip") }
         }
+        maven("https://libraries.minecraft.net/") {
+            content { includeGroup("com.mojang") }
+        }
         mavenCentral {
             content { includeGroup("net.kyori") }
         }