Fix for chunk packets causing client to corrupt biome ID when run with Thermos (#14)

Author: Cleptomania

src/main/java/com/gtnewhorizons/neid/Common.java

@@ -0,0 +1,15 @@
+package com.gtnewhorizons.neid;
+
+public class Common {
+
+    public static boolean thermosTainted;
+
+    static {
+        try {
+            Class.forName("org.bukkit.World");
+            Common.thermosTainted = true;
+        } catch (ClassNotFoundException e) {
+            Common.thermosTainted = false;
+        }
+    }
+}

src/main/java/com/gtnewhorizons/neid/mixins/Mixins.java

@@ -7,6 +7,7 @@
 import java.util.Set;
 import java.util.function.Supplier;
 
+import com.gtnewhorizons.neid.Common;
 import com.gtnewhorizons.neid.NEIDConfig;
 
 import cpw.mods.fml.relauncher.FMLLaunchHandler;
@@ -20,14 +21,19 @@ public enum Mixins {
             "minecraft.MixinExtendedBlockStorage",
             "minecraft.MixinStatList",
             "minecraft.MixinBlockFire",
-            "minecraft.MixinS21PacketChunkData",
             "minecraft.MixinS22PacketMultiBlockChange",
             "minecraft.MixinS24PacketBlockAction",
             "minecraft.MixinS26PacketMapChunkBulk",
             "minecraft.MixinItemInWorldManager",
             "minecraft.MixinAnvilChunkLoader",
             "minecraft.MixinBlock"
         ).setApplyIf(() -> true)),
+    VANILLA_STARTUP_ONLY_WITHOUT_THERMOS(new Builder("Start Vanilla No Thermos").addTargetedMod(TargetedMod.VANILLA).setSide(Side.BOTH).setPhase(Phase.EARLY).addMixinClasses(
+        "minecraft.MixinS21PacketChunkData"
+    ).setApplyIf(() -> !Common.thermosTainted)),
+    VANILLA_STARTUP_ONLY_WITH_THERMOS(new Builder("Start Vanilla with Thermos").addTargetedMod(TargetedMod.VANILLA).setSide(Side.BOTH).setPhase(Phase.EARLY).addMixinClasses(
+        "minecraft.MixinS21PacketChunkDataThermosTainted"
+    ).setApplyIf(() -> Common.thermosTainted)),
     VANILLA_STARTUP_CLIENT(new Builder("Start Vanilla Client").addTargetedMod(TargetedMod.VANILLA)
         .setSide(Side.CLIENT).setPhase(Phase.EARLY).addMixinClasses(
             "minecraft.client.MixinRenderGlobal",

src/main/java/com/gtnewhorizons/neid/mixins/early/minecraft/MixinS21PacketChunkDataThermosTainted.java

@@ -0,0 +1,113 @@
+package com.gtnewhorizons.neid.mixins.early.minecraft;
+
+import net.minecraft.network.play.server.S21PacketChunkData;
+import net.minecraft.world.chunk.NibbleArray;
+import net.minecraft.world.chunk.storage.ExtendedBlockStorage;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Constant;
+import org.spongepowered.asm.mixin.injection.ModifyConstant;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+import com.gtnewhorizons.neid.Constants;
+import com.gtnewhorizons.neid.mixins.interfaces.IExtendedBlockStorageMixin;
+import com.llamalad7.mixinextras.injector.WrapWithCondition;
+import com.llamalad7.mixinextras.sugar.Local;
+import com.llamalad7.mixinextras.sugar.ref.LocalIntRef;
+
+@Mixin(S21PacketChunkData.class)
+public class MixinS21PacketChunkDataThermosTainted {
+
+    private static final byte[] fakeByteArray = new byte[0];
+    private static final NibbleArray fakeNibbleArray = new NibbleArray(0, 0);
+
+    @ModifyConstant(
+            method = "<clinit>",
+            constant = @Constant(intValue = Constants.VANILLA_BYTES_PER_CHUNK),
+            require = 1)
+    private static int neid$OverrideBytesPerChunk1(int old) {
+        return Constants.BYTES_PER_CHUNK;
+    }
+
+    @ModifyConstant(
+            method = "func_149275_c()I",
+            constant = @Constant(intValue = Constants.VANILLA_BYTES_PER_CHUNK),
+            require = 1)
+    private static int neid$OverrideBytesPerChunk2(int i) {
+        return Constants.BYTES_PER_CHUNK;
+    }
+
+    @ModifyConstant(
+            method = "readPacketData",
+            constant = @Constant(intValue = Constants.VANILLA_BYTES_PER_EBS),
+            require = 1)
+    private static int neid$OverrideBytesPerEBS(int i) {
+        return Constants.BYTES_PER_EBS;
+    }
+
+    @Redirect(
+            method = "func_149269_a",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/world/chunk/storage/ExtendedBlockStorage;getBlockLSBArray()[B"),
+            require = 1)
+    private static byte[] neid$injectNewDataCopy(ExtendedBlockStorage ebs, @Local(ordinal = 0) byte[] thebytes,
+            @Local(ordinal = 1) LocalIntRef offset) {
+        IExtendedBlockStorageMixin ebsMixin = (IExtendedBlockStorageMixin) ebs;
+        byte[] data = ebsMixin.getBlockData();
+        System.arraycopy(data, 0, thebytes, offset.get(), Constants.BLOCKS_PER_EBS * 2);
+        offset.set(offset.get() + (Constants.BLOCKS_PER_EBS * 2));
+        return fakeByteArray;
+    }
+
+    @WrapWithCondition(
+            method = "func_149269_a",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Ljava/lang/System;arraycopy(Ljava/lang/Object;ILjava/lang/Object;II)V",
+                    ordinal = 0),
+            require = 1)
+    private static boolean neid$cancelLSBArrayCopy(Object a, int i, Object b, int j, int k) {
+        return false;
+    }
+
+    @Redirect(
+            method = "func_149269_a",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/world/chunk/storage/ExtendedBlockStorage;getMetadataArray()Lnet/minecraft/world/chunk/NibbleArray;"),
+            require = 1)
+    private static NibbleArray neid$injectNewMetadataCopy(ExtendedBlockStorage ebs, @Local(ordinal = 0) byte[] thebytes,
+            @Local(ordinal = 1) LocalIntRef offset) {
+        IExtendedBlockStorageMixin ebsMixin = (IExtendedBlockStorageMixin) ebs;
+        byte[] meta = ebsMixin.getBlockMeta();
+        System.arraycopy(meta, 0, thebytes, offset.get(), Constants.BLOCKS_PER_EBS * 2);
+        offset.set(offset.get() + (Constants.BLOCKS_PER_EBS * 2));
+        return fakeNibbleArray;
+    }
+
+    @WrapWithCondition(
+            method = "func_149269_a",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/world/chunk/NibbleArray;copyToByteArray([BI)I",
+                    ordinal = 0,
+                    remap = false),
+            require = 1)
+    private static boolean neid$cancelMetadataArrayCopy(NibbleArray nibbleArray, byte[] bytes, int i) {
+        return false;
+    }
+
+    @Redirect(
+            method = "func_149269_a",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/world/chunk/storage/ExtendedBlockStorage;getBlockMSBArray()Lnet/minecraft/world/chunk/NibbleArray;",
+                    ordinal = 0),
+            require = 1)
+    private static NibbleArray neid$nukeMSBLoop(ExtendedBlockStorage ebs) {
+        return null;
+    }
+
+}