LabyMod 1.16 features

src/main/java/de/hglabor/utils/noriskutils/ClientPayloadBuffer.java

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+package de.hglabor.utils.noriskutils;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.handler.codec.DecoderException;
+import io.netty.handler.codec.EncoderException;
+
+import java.nio.charset.StandardCharsets;
+
+/**
+ * Payload buffer to encode or decode
+ * client plugin messages
+ * Encoding and decoding flow from
+ * wiki.vg
+ *
+ * @version 1.0
+ */
+public final class ClientPayloadBuffer {  //final because it seems to be convention in here
+
+    /**
+     * The bytebuffer to store the bytes
+     */
+    private final ByteBuf byteBuf;
+
+    /**
+     * Constructor to create a buffer out of an existing
+     * payload
+     *
+     * @param payload The payload byte array
+     */
+    public ClientPayloadBuffer(byte[] payload) {
+        this.byteBuf = Unpooled.wrappedBuffer(payload);
+    }
+
+    /**
+     * Constructor for creating a new
+     * buffer being empty
+     */
+    public ClientPayloadBuffer() {
+        //Creating new buffer
+        this.byteBuf = Unpooled.buffer();
+    }
+
+    /**
+     * Getter for the byte buf
+     * because it's needed to send it to the player
+     *
+     * @return The bytebuf of the buffer
+     */
+    public ByteBuf getByteBuf() {
+        return this.byteBuf;
+    }
+
+    /**
+     * Writing a string into the buffer
+     *
+     * @param stringToWrite The string to write
+     */
+    public void writeString(String stringToWrite) {
+        byte[] stringBytes = stringToWrite.getBytes(StandardCharsets.UTF_8);
+
+        if (stringBytes.length > Short.MAX_VALUE) {
+            throw new EncoderException("String was too big");
+        }
+        this.writeLengthVarInt(stringBytes.length);
+        this.byteBuf.writeBytes(stringBytes);
+    }
+
+    /**
+     * Writing the length as varint into the buffer
+     * code of minecraft protocol
+     *
+     * @param length The length of the string byte
+     */
+    private void writeLengthVarInt(int length) {
+        while ((length & -128) != 0) {
+            this.byteBuf.writeByte(length & 127 | 128);
+            length >>>= 7;
+        }
+        this.byteBuf.writeByte(length);
+    }
+
+    /**
+     * Reading the length out of a varInt
+     * using mc protocol decoding
+     *
+     * @return The length
+     */
+    private int readLengthVarInt() {
+        int readCount = 0;
+        int result = 0;
+        byte readByte;
+
+        do {
+            readByte = this.byteBuf.readByte();
+            result |= (readByte & 127) << readCount++ * 7;
+            if (readCount > 5) {
+                throw new DecoderException("Invalid war int size");
+            }
+        } while ((readByte & 128) == 128);
+
+        return result;
+    }
+
+    /**
+     * Reading a string out of
+     * the byte buf
+     *
+     * @return The read string
+     */
+    public String readString() {
+        int stringByteArrayLength = this.readLengthVarInt();
+
+        if (stringByteArrayLength < 0 || stringByteArrayLength > 4 * Short.MAX_VALUE) {
+            throw new DecoderException("Invalid string length");
+        }
+        byte[] stringBytes = new byte[stringByteArrayLength];
+        this.byteBuf.readBytes(stringBytes);
+
+        return new String(stringBytes, StandardCharsets.UTF_8);
+    }
+}

src/main/java/de/hglabor/utils/noriskutils/listener/LabyModOldPvP.java

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+package de.hglabor.utils.noriskutils.listener;
+
+import com.google.gson.JsonObject;
+import de.hglabor.utils.noriskutils.ClientPayloadBuffer;
+import de.hglabor.utils.noriskutils.NMSUtils;
+import net.minecraft.server.v1_16_R3.MinecraftKey;
+import net.minecraft.server.v1_16_R3.PacketDataSerializer;
+import net.minecraft.server.v1_16_R3.PacketPlayOutCustomPayload;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.bukkit.plugin.messaging.PluginMessageListener;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Implementation for LabyMods new combat system
+ * in the 1.16.5 for HGLabor.de
+ *
+ * Use `new LabyModOldPvP(plugin);` to register listening
+ *
+ * @author Raik
+ * @version 1.0
+ */
+public class LabyModOldPvP implements PluginMessageListener {
+
+    /**
+     * Channel name used by LabyMod for communication
+     */
+    private static final String CHANNEL_NAME = "labymod3:main";
+
+    /**
+     * Constructor setting up the the listening
+     *
+     * @param plugin The plugin instance
+     */
+    public LabyModOldPvP(JavaPlugin plugin) {
+        //Register listening
+        plugin.getServer().getMessenger().registerIncomingPluginChannel(plugin, CHANNEL_NAME, this);
+    }
+
+
+    /**
+     * A method that will be thrown when a PluginMessageSource sends a plugin
+     * message on a registered channel.
+     * Catching labymods join message to send perm message
+     *
+     * @param channel Channel that the message was sent through.
+     * @param player  Source of the message.
+     * @param message The raw message that was sent.
+     */
+    @Override
+    public void onPluginMessageReceived(@NotNull String channel, @NotNull Player player, byte[] message) {
+        if (!channel.equals(CHANNEL_NAME)) {
+            return;
+        }
+
+        ClientPayloadBuffer payloadBuffer = new ClientPayloadBuffer(message);
+        //Only execute on join / INFO message
+        if (payloadBuffer.readString().equals("INFO")) {
+            this.sendPermissions(player);
+        }
+    }
+
+    /**
+     * Send the permission to the player
+     * using plugin channels
+     *
+     * @param receiver The receiver of the permissions
+     */
+    private void sendPermissions(Player receiver) {
+        ClientPayloadBuffer payloadBuffer = new ClientPayloadBuffer();
+        //Set permission key
+        payloadBuffer.writeString("PERMISSIONS");
+        //Set permission
+        payloadBuffer.writeString(LabyModSettings.getSettingsAsJsonString());
+
+        //Creating packet
+        PacketPlayOutCustomPayload payloadPacket = new PacketPlayOutCustomPayload(new MinecraftKey(CHANNEL_NAME)
+                , new PacketDataSerializer(payloadBuffer.getByteBuf()));
+
+        //Sending packet
+        NMSUtils.sendPacket(receiver, payloadPacket);
+    }
+
+    /**
+     * Enum containing every changed
+     * settings which will be transmitted to the player
+     */
+    private enum LabyModSettings {
+        IMPROVED_LAVA(true), //Minecraft bug fix provided by LabyMod
+        RANGE(true), //Adding 1.8 Range to 1.16
+        SLOWDOWN(true); //Adding slowdown on blocking
+
+        /**
+         * The state whether a features is enabled or not
+         */
+        private final boolean state;
+
+        LabyModSettings(boolean state) {
+            this.state = state;
+        }
+
+        /**
+         * Getting all Settings as Json String
+         * using JsonObject and looping through
+         * als set values
+         *
+         * @return The json srting
+         */
+        public static String getSettingsAsJsonString() {
+            JsonObject settings = new JsonObject();
+
+            //Looping through settings to add them
+            for (LabyModSettings setting: values()) {
+                settings.addProperty(setting.name(), setting.state);
+            }
+
+            return settings.toString();
+        }
+    }
+}