Small startup time improvements

api/src/main/java/com/viaversion/viaversion/api/ViaManager.java

@@ -131,4 +131,11 @@ public interface ViaManager {
      * @param runnable runnable to be executed
      */
     void addEnableListener(Runnable runnable);
+
+    /**
+     * Returns whether the manager has been initialized (and protocols have been loaded).
+     *
+     * @return whether the manager has been initialized
+     */
+    boolean isInitialized();
 }

api/src/main/java/com/viaversion/viaversion/api/configuration/ViaVersionConfig.java

@@ -256,6 +256,8 @@ public interface ViaVersionConfig {
      */
     boolean is1_13TeamColourFix();
 
+    boolean shouldRegisterUserConnectionOnJoin();
+
     /**
      * Should we fix shift quick move action for 1.12 clients
      *

bukkit-legacy/src/main/java/com/viaversion/viaversion/bukkit/listeners/ViaBukkitListener.java

@@ -57,10 +57,12 @@ public class ViaBukkitListener extends ViaListener implements Listener {
      */
     @Override
     public void register() {
-        if (isRegistered()) return;
+        if (isRegistered()) {
+            return;
+        }
 
-        plugin.getServer().getPluginManager().registerEvents(this, plugin);
         setRegistered(true);
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
     }
 
     public Plugin getPlugin() {

bukkit/src/main/java/com/viaversion/viaversion/ViaVersionPlugin.java

@@ -27,6 +27,7 @@ import com.viaversion.viaversion.api.platform.UnsupportedSoftware;
 import com.viaversion.viaversion.api.platform.ViaPlatform;
 import com.viaversion.viaversion.bukkit.commands.BukkitCommandHandler;
 import com.viaversion.viaversion.bukkit.commands.BukkitCommandSender;
+import com.viaversion.viaversion.bukkit.listeners.JoinListener;
 import com.viaversion.viaversion.bukkit.platform.BukkitViaAPI;
 import com.viaversion.viaversion.bukkit.platform.BukkitViaConfig;
 import com.viaversion.viaversion.bukkit.platform.BukkitViaInjector;
@@ -35,6 +36,7 @@ import com.viaversion.viaversion.bukkit.platform.BukkitViaTask;
 import com.viaversion.viaversion.bukkit.platform.BukkitViaTaskTask;
 import com.viaversion.viaversion.bukkit.platform.PaperViaInjector;
 import com.viaversion.viaversion.dump.PluginInfo;
+import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.ChatRewriter;
 import com.viaversion.viaversion.unsupported.UnsupportedPlugin;
 import com.viaversion.viaversion.unsupported.UnsupportedServerSoftware;
 import com.viaversion.viaversion.util.GsonUtil;
@@ -79,6 +81,15 @@ public class ViaVersionPlugin extends JavaPlugin implements ViaPlatform<Player>
 
         // Config magic
         conf = new BukkitViaConfig();
+
+        // Load a bunch of classes early with slow reflection and more classloading
+        Via.getManager().getScheduler().execute(() -> {
+            if (conf.shouldRegisterUserConnectionOnJoin()) {
+                JoinListener.init();
+            }
+
+            ChatRewriter.init();
+        });
     }
 
     @Override

bukkit/src/main/java/com/viaversion/viaversion/bukkit/listeners/JoinListener.java

@@ -42,13 +42,13 @@ public class JoinListener implements Listener {
     private static final Field CHANNEL;
 
     static {
-        Method gh = null;
-        Field conn = null, nm = null, ch = null;
+        Method getHandleMethod = null;
+        Field gamePacketListenerField = null, connectionField = null, channelField = null;
         try {
-            gh = NMSUtil.obc("entity.CraftPlayer").getDeclaredMethod("getHandle");
-            conn = findField(gh.getReturnType(), "PlayerConnection", "ServerGamePacketListenerImpl");
-            nm = findField(conn.getType(), "NetworkManager", "Connection");
-            ch = findField(nm.getType(), "Channel");
+            getHandleMethod = NMSUtil.obc("entity.CraftPlayer").getDeclaredMethod("getHandle");
+            gamePacketListenerField = findField(getHandleMethod.getReturnType(), "PlayerConnection", "ServerGamePacketListenerImpl");
+            connectionField = findField(gamePacketListenerField.getType(), "NetworkManager", "Connection");
+            channelField = findField(connectionField.getType(), Class.forName("io.netty.channel.Channel"));
         } catch (NoSuchMethodException | NoSuchFieldException | ClassNotFoundException e) {
             Via.getPlatform().getLogger().log(
                     Level.WARNING,
@@ -56,27 +56,47 @@ public class JoinListener implements Listener {
                             "Login race condition fixer will be disabled.\n" +
                             " Some plugins that use ViaAPI on join event may work incorrectly.", e);
         }
-        GET_HANDLE = gh;
-        CONNECTION = conn;
-        NETWORK_MANAGER = nm;
-        CHANNEL = ch;
+        GET_HANDLE = getHandleMethod;
+        CONNECTION = gamePacketListenerField;
+        NETWORK_MANAGER = connectionField;
+        CHANNEL = channelField;
+    }
+
+    public static void init() {
     }
 
     // Loosely search a field with any name, as long as it matches a type name.
-    private static Field findField(Class<?> cl, String... types) throws NoSuchFieldException {
-        for (Field field : cl.getDeclaredFields()) {
+    private static Field findField(Class<?> clazz, String... types) throws NoSuchFieldException {
+        for (Field field : clazz.getDeclaredFields()) {
+            String fieldTypeName = field.getType().getSimpleName();
             for (String type : types) {
-                if (field.getType().getSimpleName().equals(type)) {
-                    if (!Modifier.isPublic(field.getModifiers())) {
-                        field.setAccessible(true);
-                    }
-                    return field;
+                if (!fieldTypeName.equals(type)) {
+                    continue;
                 }
+
+                if (!Modifier.isPublic(field.getModifiers())) {
+                    field.setAccessible(true);
+                }
+                return field;
             }
         }
         throw new NoSuchFieldException(types[0]);
     }
 
+    private static Field findField(Class<?> clazz, Class<?> fieldType) throws NoSuchFieldException {
+        for (Field field : clazz.getDeclaredFields()) {
+            if (field.getType() != fieldType) {
+                continue;
+            }
+
+            if (!Modifier.isPublic(field.getModifiers())) {
+                field.setAccessible(true);
+            }
+            return field;
+        }
+        throw new NoSuchFieldException(fieldType.getSimpleName());
+    }
+
     @EventHandler(priority = EventPriority.LOWEST)
     public void onJoin(PlayerJoinEvent e) {
         if (CHANNEL == null) return;

bukkit/src/main/java/com/viaversion/viaversion/bukkit/platform/BukkitViaConfig.java

@@ -32,6 +32,7 @@ public class BukkitViaConfig extends AbstractViaConfig {
     private boolean hitboxFix1_14;
     private String blockConnectionMethod;
     private boolean armorToggleFix;
+    private boolean registerUserConnectionOnJoin;
 
     public BukkitViaConfig() {
         super(new File(((Plugin) Via.getPlatform()).getDataFolder(), "config.yml"));
@@ -41,6 +42,7 @@ public class BukkitViaConfig extends AbstractViaConfig {
     @Override
     protected void loadFields() {
         super.loadFields();
+        registerUserConnectionOnJoin = getBoolean("register-userconnections-on-join", true);
         quickMoveActionFix = getBoolean("quick-move-action-fix", false);
         hitboxFix1_9 = getBoolean("change-1_9-hitbox", false);
         hitboxFix1_14 = getBoolean("change-1_14-hitbox", false);
@@ -52,6 +54,11 @@ public class BukkitViaConfig extends AbstractViaConfig {
     protected void handleConfig(Map<String, Object> config) {
     }
 
+    @Override
+    public boolean shouldRegisterUserConnectionOnJoin() {
+        return registerUserConnectionOnJoin;
+    }
+
     @Override
     public boolean is1_12QuickMoveActionFix() {
         return quickMoveActionFix;

bukkit/src/main/java/com/viaversion/viaversion/bukkit/platform/BukkitViaInjector.java

@@ -187,7 +187,7 @@ public class BukkitViaInjector extends LegacyViaInjector {
 
     @Override
     public boolean lateProtocolVersionSetting() {
-        return !PaperViaInjector.PAPER_PROTOCOL_METHOD && !HAS_SHARED_CONSTANTS;
+        return !(PaperViaInjector.PAPER_PROTOCOL_METHOD || HAS_SHARED_CONSTANTS);
     }
 
     public boolean isBinded() {

bukkit/src/main/java/com/viaversion/viaversion/bukkit/platform/BukkitViaLoader.java

@@ -51,16 +51,13 @@ import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
-import org.bukkit.event.HandlerList;
 import org.bukkit.event.Listener;
 import org.bukkit.scheduler.BukkitTask;
 
 public class BukkitViaLoader implements ViaPlatformLoader {
-    private final ViaVersionPlugin plugin;
 
-    private final Set<Listener> listeners = new HashSet<>();
     private final Set<BukkitTask> tasks = new HashSet<>();
-
+    private final ViaVersionPlugin plugin;
     private HandItemCache handItemCache;
 
     public BukkitViaLoader(ViaVersionPlugin plugin) {
@@ -68,21 +65,21 @@ public class BukkitViaLoader implements ViaPlatformLoader {
     }
 
     public void registerListener(Listener listener) {
-        Bukkit.getPluginManager().registerEvents(storeListener(listener), plugin);
+        plugin.getServer().getPluginManager().registerEvents(listener, plugin);
     }
 
+    @Deprecated/*(forRemoval = true)*/
     public <T extends Listener> T storeListener(T listener) {
-        listeners.add(listener);
         return listener;
     }
 
     @Override
     public void load() {
-        // Update Listener
         registerListener(new UpdateListener());
 
-        // Login listener
-        registerListener(new JoinListener());
+        if (Via.getConfig().shouldRegisterUserConnectionOnJoin()) {
+            registerListener(new JoinListener());
+        }
 
         /* Base Protocol */
         final ViaVersionPlugin plugin = (ViaVersionPlugin) Bukkit.getPluginManager().getPlugin("ViaVersion");
@@ -92,13 +89,18 @@ public class BukkitViaLoader implements ViaPlatformLoader {
             ProtocolSupportCompat.registerPSConnectListener(plugin);
         }
 
+        if (!Via.getAPI().getServerVersion().isKnown()) {
+            Via.getPlatform().getLogger().severe("Server version has not been loaded yet, cannot register additional listeners");
+            return;
+        }
+
         int serverProtocolVersion = Via.getAPI().getServerVersion().lowestSupportedVersion();
 
         /* 1.9 client to 1.8 server */
         if (serverProtocolVersion < ProtocolVersion.v1_9.getVersion()) {
-            storeListener(new ArmorListener(plugin)).register();
-            storeListener(new DeathListener(plugin)).register();
-            storeListener(new BlockListener(plugin)).register();
+            new ArmorListener(plugin).register();
+            new DeathListener(plugin).register();
+            new BlockListener(plugin).register();
 
             if (plugin.getConf().isItemCache()) {
                 handItemCache = new HandItemCache();
@@ -110,7 +112,7 @@ public class BukkitViaLoader implements ViaPlatformLoader {
             boolean use1_9Fix = plugin.getConf().is1_9HitboxFix() && serverProtocolVersion < ProtocolVersion.v1_9.getVersion();
             if (use1_9Fix || plugin.getConf().is1_14HitboxFix()) {
                 try {
-                    storeListener(new PlayerSneakListener(plugin, use1_9Fix, plugin.getConf().is1_14HitboxFix())).register();
+                    new PlayerSneakListener(plugin, use1_9Fix, plugin.getConf().is1_14HitboxFix()).register();
                 } catch (ReflectiveOperationException e) {
                     Via.getPlatform().getLogger().warning("Could not load hitbox fix - please report this on our GitHub");
                     e.printStackTrace();
@@ -121,7 +123,7 @@ public class BukkitViaLoader implements ViaPlatformLoader {
         if (serverProtocolVersion < ProtocolVersion.v1_15.getVersion()) {
             try {
                 Class.forName("org.bukkit.event.entity.EntityToggleGlideEvent");
-                storeListener(new EntityToggleGlideListener(plugin)).register();
+                new EntityToggleGlideListener(plugin).register();
             } catch (ClassNotFoundException ignored) {
             }
         }
@@ -138,12 +140,12 @@ public class BukkitViaLoader implements ViaPlatformLoader {
                 }
             }
             if (paper) {
-                storeListener(new PaperPatch(plugin)).register();
+                new PaperPatch(plugin).register();
             }
         }
 
         if (serverProtocolVersion < ProtocolVersion.v1_19_4.getVersion() && plugin.getConf().isArmorToggleFix()) {
-            storeListener(new ArmorToggleListener(plugin)).register();
+            new ArmorToggleListener(plugin).register();
         }
 
         /* Providers */
@@ -189,16 +191,12 @@ public class BukkitViaLoader implements ViaPlatformLoader {
         }
         if (serverProtocolVersion < ProtocolVersion.v1_19.getVersion()) {
             Via.getManager().getProviders().use(AckSequenceProvider.class, new BukkitAckSequenceProvider(plugin));
-            storeListener(new BlockBreakListener(plugin)).register();
+            new BlockBreakListener(plugin).register();
         }
     }
 
     @Override
     public void unload() {
-        for (Listener listener : listeners) {
-            HandlerList.unregisterAll(listener);
-        }
-        listeners.clear();
         for (BukkitTask task : tasks) {
             task.cancel();
         }

common/src/main/java/com/viaversion/viaversion/ViaManagerImpl.java

@@ -63,6 +63,7 @@ public class ViaManagerImpl implements ViaManager {
     private final Set<String> subPlatforms = new HashSet<>();
     private List<Runnable> enableListeners = new ArrayList<>();
     private PlatformTask<?> mappingLoadingTask;
+    private boolean initialized;
 
     public ViaManagerImpl(ViaPlatform<?> platform, ViaInjector injector, ViaCommandHandler commandHandler, ViaPlatformLoader loader) {
         this.platform = platform;
@@ -105,6 +106,8 @@ public class ViaManagerImpl implements ViaManager {
             listener.run();
         }
         enableListeners = null;
+
+        initialized = true;
     }
 
     public void onServerLoaded() {
@@ -149,9 +152,6 @@ public class ViaManagerImpl implements ViaManager {
         // Check for unsupported plugins/software
         unsupportedSoftwareWarning();
 
-        // Load Listeners / Tasks
-        protocolManager.onServerLoaded();
-
         // Load Platform
         loader.load();
         // Common tasks
@@ -324,6 +324,11 @@ public class ViaManagerImpl implements ViaManager {
         enableListeners.add(runnable);
     }
 
+    @Override
+    public boolean isInitialized() {
+        return initialized;
+    }
+
     public static final class ViaManagerBuilder {
         private ViaPlatform<?> platform;
         private ViaInjector injector;

common/src/main/java/com/viaversion/viaversion/configuration/AbstractViaConfig.java

@@ -383,6 +383,11 @@ public abstract class AbstractViaConfig extends Config implements ViaVersionConf
         return nbtArrayFix;
     }
 
+    @Override
+    public boolean shouldRegisterUserConnectionOnJoin() {
+        return false;
+    }
+
     @Override
     public boolean is1_12QuickMoveActionFix() {
         return false;

common/src/main/java/com/viaversion/viaversion/protocol/ProtocolManagerImpl.java

@@ -109,11 +109,10 @@ public class ProtocolManagerImpl implements ProtocolManager {
 
     // Input Version -> Output Version & Protocol (Allows fast lookup)
     private final Int2ObjectMap<Int2ObjectMap<Protocol>> registryMap = new Int2ObjectOpenHashMap<>(32);
-    private final Map<Class<? extends Protocol>, Protocol<?, ?, ?, ?>> protocols = new HashMap<>();
+    private final Map<Class<? extends Protocol>, Protocol<?, ?, ?, ?>> protocols = new HashMap<>(64);
     private final Map<ProtocolPathKey, List<ProtocolPathEntry>> pathCache = new ConcurrentHashMap<>();
     private final Set<Integer> supportedVersions = new HashSet<>();
     private final List<Pair<Range<Integer>, Protocol>> baseProtocols = Lists.newCopyOnWriteArrayList();
-    private final List<Protocol> registerList = new ArrayList<>();
 
     private final ReadWriteLock mappingLoaderLock = new ReentrantReadWriteLock();
     private Map<Class<? extends Protocol>, CompletableFuture<Void>> mappingLoaderFutures = new HashMap<>();
@@ -208,11 +207,9 @@ public class ProtocolManagerImpl implements ProtocolManager {
             protocolMap.put(serverVersion, protocol);
         }
 
-        if (Via.getPlatform().isPluginEnabled()) {
-            protocol.register(Via.getManager().getProviders());
+        protocol.register(Via.getManager().getProviders());
+        if (Via.getManager().isInitialized()) {
             refreshVersions();
-        } else {
-            registerList.add(protocol);
         }
 
         if (protocol.hasMappingDataToLoad()) {
@@ -232,11 +229,9 @@ public class ProtocolManagerImpl implements ProtocolManager {
         baseProtocol.initialize();
 
         baseProtocols.add(new Pair<>(supportedProtocols, baseProtocol));
-        if (Via.getPlatform().isPluginEnabled()) {
-            baseProtocol.register(Via.getManager().getProviders());
+        baseProtocol.register(Via.getManager().getProviders());
+        if (Via.getManager().isInitialized()) {
             refreshVersions();
-        } else {
-            registerList.add(baseProtocol);
         }
     }
 
@@ -498,16 +493,6 @@ public class ProtocolManagerImpl implements ProtocolManager {
         return new PacketWrapperImpl(packetId, buf, connection);
     }
 
-    /**
-     * Called when the server is enabled, to register any non-registered listeners.
-     */
-    public void onServerLoaded() {
-        for (Protocol protocol : registerList) {
-            protocol.register(Via.getManager().getProviders());
-        }
-        registerList.clear();
-    }
-
     public void shutdownLoaderExecutor() {
         Preconditions.checkArgument(!mappingsLoaded);
 

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13to1_12_2/ChatRewriter.java

@@ -28,6 +28,10 @@ import com.viaversion.viaversion.libs.kyori.adventure.text.serializer.legacy.Leg
 
 public final class ChatRewriter {
     public static final GsonComponentSerializer HOVER_GSON_SERIALIZER = GsonComponentSerializer.builder().emitLegacyHoverEvent().legacyHoverEventSerializer(NBTLegacyHoverEventSerializer.get()).build();
+    public static final JsonElement EMPTY_COMPONENT = GsonComponentSerializer.gson().serializeToTree(Component.empty());
+
+    public static void init() {
+    }
 
     public static String legacyTextToJsonString(String message, boolean itemData) {
         // Not used for chat messages, so no need for url extraction

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_19_4to1_19_3/Protocol1_19_4To1_19_3.java

@@ -28,6 +28,7 @@ import com.viaversion.viaversion.api.type.types.version.Types1_19_4;
 import com.viaversion.viaversion.data.entity.EntityTrackerBase;
 import com.viaversion.viaversion.libs.kyori.adventure.text.Component;
 import com.viaversion.viaversion.libs.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
+import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.ChatRewriter;
 import com.viaversion.viaversion.protocols.protocol1_19_3to1_19_1.ClientboundPackets1_19_3;
 import com.viaversion.viaversion.protocols.protocol1_19_3to1_19_1.ServerboundPackets1_19_3;
 import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.data.MappingData;
@@ -42,7 +43,6 @@ import java.util.Base64;
 public final class Protocol1_19_4To1_19_3 extends AbstractProtocol<ClientboundPackets1_19_3, ClientboundPackets1_19_4, ServerboundPackets1_19_3, ServerboundPackets1_19_4> {
 
     public static final MappingData MAPPINGS = new MappingData();
-    private static final JsonElement EMPTY_COMPONENT = GsonComponentSerializer.gson().serializeToTree(Component.empty());
     private final EntityPackets entityRewriter = new EntityPackets(this);
     private final InventoryPackets itemRewriter = new InventoryPackets(this);
 
@@ -60,7 +60,6 @@ public final class Protocol1_19_4To1_19_3 extends AbstractProtocol<ClientboundPa
         soundRewriter.registerSound(ClientboundPackets1_19_3.ENTITY_SOUND);
         soundRewriter.register1_19_3Sound(ClientboundPackets1_19_3.SOUND);
 
-
         new CommandRewriter<ClientboundPackets1_19_3>(this) {
             @Override
             public void handleArgument(final PacketWrapper wrapper, final String argumentType) throws Exception {
@@ -78,7 +77,7 @@ public final class Protocol1_19_4To1_19_3 extends AbstractProtocol<ClientboundPa
             if (element != null) {
                 wrapper.write(Type.COMPONENT, element);
             } else {
-                wrapper.write(Type.COMPONENT, EMPTY_COMPONENT);
+                wrapper.write(Type.COMPONENT, ChatRewriter.EMPTY_COMPONENT);
             }
 
             final String iconBase64 = wrapper.read(Type.OPTIONAL_STRING);

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_9to1_8/packets/InventoryPackets.java

@@ -53,13 +53,10 @@ public class InventoryPackets {
                                 // Send 2 properties, splitting it into enchantID & level
                                 final short level = (short) (value >> 8);
                                 final short enchantID = (short) (value & 0xFF);
-                                wrapper.create(wrapper.getId(), new PacketHandler() {
-                                    @Override
-                                    public void handle(PacketWrapper wrapper) throws Exception {
-                                        wrapper.write(Type.UNSIGNED_BYTE, windowId);
-                                        wrapper.write(Type.SHORT, property);
-                                        wrapper.write(Type.SHORT, enchantID);
-                                    }
+                                wrapper.create(wrapper.getId(), propertyPacket -> {
+                                    propertyPacket.write(Type.UNSIGNED_BYTE, windowId);
+                                    propertyPacket.write(Type.SHORT, property);
+                                    propertyPacket.write(Type.SHORT, enchantID);
                                 }).scheduleSend(Protocol1_9To1_8.class);
 
                                 wrapper.set(Type.SHORT, 0, (short) (property + 3));

common/src/main/resources/assets/viaversion/config.yml

@@ -102,6 +102,9 @@ tracking-max-kick-msg: "You are sending too many packets, :("
 #                 MULTIPLE VERSIONS OPTIONS                #
 #----------------------------------------------------------#
 #
+# Whether to make sure ViaVersion's UserConnection object is already available in the PlayerJoinEvent.
+# You may disable this for faster startup/join time if you are 100% sure no plugin requires this.
+register-userconnections-on-join: true
 # Should we enable our hologram patch?
 # If they're in the wrong place enable this
 hologram-patch: false