FabricProxyLite support (#80)

* FabricProxyLite support - apply workaround of changing the limit of 255 to instead the Short.MAX_VALUE int, as also done by Paper/Spigot.

src/main/java/org/geysermc/floodgate/addon/data/FabricDataHandler.java

@@ -12,7 +12,7 @@ import net.minecraft.server.network.ServerLoginPacketListenerImpl;
 import org.geysermc.floodgate.MinecraftServerHolder;
 import org.geysermc.floodgate.api.logger.FloodgateLogger;
 import org.geysermc.floodgate.mixin.ConnectionMixin;
-import org.geysermc.floodgate.mixin.ClientIntentionPacketMixin;
+import org.geysermc.floodgate.mixin.ClientIntentionPacketMixinInterface;
 import org.geysermc.floodgate.mixin_interface.ServerLoginPacketListenerSetter;
 import com.mojang.authlib.GameProfile;
 import io.netty.channel.ChannelHandlerContext;
@@ -48,7 +48,7 @@ public final class FabricDataHandler extends CommonDataHandler {
     protected Object setHostname(Object handshakePacket, String hostname) {
         // While it would be ideal to simply create a new handshake packet, the packet constructor
         // does not allow us to set the protocol version
-        ((ClientIntentionPacketMixin) handshakePacket).setAddress(hostname);
+        ((ClientIntentionPacketMixinInterface) handshakePacket).setAddress(hostname);
         return handshakePacket;
     }
 

src/main/java/org/geysermc/floodgate/mixin/ClientIntentionPacketMixin.java

@@ -2,13 +2,13 @@ package org.geysermc.floodgate.mixin;
 
 import net.minecraft.network.protocol.handshake.ClientIntentionPacket;
 import org.spongepowered.asm.mixin.Mixin;
-import org.spongepowered.asm.mixin.Mutable;
-import org.spongepowered.asm.mixin.gen.Accessor;
+import org.spongepowered.asm.mixin.injection.Constant;
+import org.spongepowered.asm.mixin.injection.ModifyConstant;
 
 @Mixin(ClientIntentionPacket.class)
-public interface ClientIntentionPacketMixin {
-
-    @Accessor("hostName")
-    @Mutable
-    void setAddress(String address);
+public class ClientIntentionPacketMixin {
+    @ModifyConstant(method = "<init>(Lnet/minecraft/network/FriendlyByteBuf;)V", constant = @Constant(intValue = 255))
+    private int floodgate$setHandshakeLength(int defaultValue) {
+            return Short.MAX_VALUE;
+    }
 }

src/main/java/org/geysermc/floodgate/mixin/ClientIntentionPacketMixinInterface.java

@@ -0,0 +1,14 @@
+package org.geysermc.floodgate.mixin;
+
+import net.minecraft.network.protocol.handshake.ClientIntentionPacket;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Mutable;
+import org.spongepowered.asm.mixin.gen.Accessor;
+
+@Mixin(ClientIntentionPacket.class)
+public interface ClientIntentionPacketMixinInterface {
+
+    @Accessor("hostName")
+    @Mutable
+    void setAddress(String address);
+}

src/main/java/org/geysermc/floodgate/util/MixinConfigPlugin.java

@@ -0,0 +1,47 @@
+package org.geysermc.floodgate.util;
+
+import net.fabricmc.loader.api.FabricLoader;
+import org.objectweb.asm.tree.ClassNode;
+import org.spongepowered.asm.mixin.extensibility.IMixinConfigPlugin;
+import org.spongepowered.asm.mixin.extensibility.IMixinInfo;
+
+import java.util.List;
+import java.util.Set;
+
+public class MixinConfigPlugin implements IMixinConfigPlugin {
+
+    @Override
+    public void onLoad(String mixinPackage) {
+    }
+
+    @Override
+    public String getRefMapperConfig() {
+        return null;
+    }
+
+    @Override
+    public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
+        if (mixinClassName.equals("org/geysermc/floodgate/mixin/ClientIntentionPacketMixin")) {
+            //returns true if fabricproxy-lite is present, therefore loading the mixin. If not present, the mixin will not be loaded.
+            return FabricLoader.getInstance().isModLoaded("fabricproxy-lite");
+        }
+        return true;
+    }
+
+    @Override
+    public void acceptTargets(Set<String> myTargets, Set<String> otherTargets) {
+    }
+
+    @Override
+    public List<String> getMixins() {
+        return null;
+    }
+
+    @Override
+    public void preApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+    }
+
+    @Override
+    public void postApply(String targetClassName, ClassNode targetClass, String mixinClassName, IMixinInfo mixinInfo) {
+    }
+}

src/main/resources/floodgate.mixins.json

@@ -5,11 +5,13 @@
   "compatibilityLevel": "JAVA_16",
   "mixins": [
     "ChunkMapMixin",
+    "ClientIntentionPacketMixinInterface",
     "ClientIntentionPacketMixin",
     "ConnectionMixin",
     "ServerConnectionListenerMixin",
     "ServerLoginPacketListenerImplMixin"
   ],
+  "plugin": "org.geysermc.floodgate.util.MixinConfigPlugin",
   "injectors": {
     "defaultRequire": 1
   }