From 7fa9ac3140fa82efe03662135b5e6711a438f26f Mon Sep 17 00:00:00 2001
From: krwminer <krwshop@hotmail.com>
Date: Sun, 6 Dec 2015 20:11:00 -0500
Subject: [PATCH] Add support to prevent Thaumcraft Taint Biome spread.

---
 src/main/java/myessentials/DepLoader.java     |  1 +
 .../BlockTaintFibersTransformer.java          | 69 +++++++++++++++++++
 .../myessentials/event/ModifyBiomeEvent.java  | 30 ++++++++
 3 files changed, 100 insertions(+)
 create mode 100644 src/main/java/myessentials/classtransformers/BlockTaintFibersTransformer.java
 create mode 100644 src/main/java/myessentials/event/ModifyBiomeEvent.java

diff --git a/src/main/java/myessentials/DepLoader.java b/src/main/java/myessentials/DepLoader.java
index 0bb4ece..5966cf1 100644
--- a/src/main/java/myessentials/DepLoader.java
+++ b/src/main/java/myessentials/DepLoader.java
@@ -29,6 +29,7 @@ public String[] getASMTransformerClass() {
             "myessentials.classtransformers.AE2PlaceTransformer",
             "myessentials.classtransformers.BlockFarmlandTransformer",
             "myessentials.classtransformers.BlockFireTransformer",
+            "myessentials.classtransformers.BlockTaintFibersTransformer",
             "myessentials.classtransformers.EntityFireballTransformer",
             "myessentials.classtransformers.EntityThrowableTransformer",
             "myessentials.classtransformers.SignClassTransformer"
diff --git a/src/main/java/myessentials/classtransformers/BlockTaintFibersTransformer.java b/src/main/java/myessentials/classtransformers/BlockTaintFibersTransformer.java
new file mode 100644
index 0000000..f3b61d4
--- /dev/null
+++ b/src/main/java/myessentials/classtransformers/BlockTaintFibersTransformer.java
@@ -0,0 +1,69 @@
+package myessentials.classtransformers;
+
+import net.minecraft.launchwrapper.IClassTransformer;
+import net.minecraft.world.World;
+
+import org.objectweb.asm.*;
+import org.objectweb.asm.commons.GeneratorAdapter;
+
+/**
+ * Patches BlockTaintFibers to add a hook for the {@link myessentials.event.ModifyBlockEvent}.
+ * <br/>
+ *
+ */
+public class BlockTaintFibersTransformer implements IClassTransformer {
+
+    private class BlockTaintFibersGeneratorAdapter extends GeneratorAdapter {
+
+        protected BlockTaintFibersGeneratorAdapter(MethodVisitor mv, int access, String name, String desc) {
+            super(Opcodes.ASM4, mv, access, name, desc);
+        }
+
+        @Override
+        public void visitJumpInsn(int opcode, Label label) {
+            super.visitJumpInsn(opcode, label);
+            if(opcode == Opcodes.IF_ICMPLT) {
+                super.visitVarInsn(Opcodes.ALOAD, 0);
+                super.visitVarInsn(Opcodes.ILOAD, 1);
+                super.visitVarInsn(Opcodes.ILOAD, 6);
+                super.visitInsn(Opcodes.IADD);
+                super.visitVarInsn(Opcodes.ILOAD, 3);
+                super.visitVarInsn(Opcodes.ILOAD, 7);
+                super.visitInsn(Opcodes.IADD);
+                super.visitMethodInsn(Opcodes.INVOKESTATIC, "myessentials/event/ModifyBiomeEvent", "checkBiome", "(Lnet/minecraft/world/World;II)Z", false);
+
+                Label elseLabel = new Label();
+                super.visitJumpInsn(Opcodes.IFEQ, elseLabel);
+                super.visitInsn(Opcodes.RETURN);
+                super.visitLabel(elseLabel);
+            }
+        }
+    }
+
+    @Override
+    public byte[] transform(String name, String srgName, byte[] bytes) {
+        if("thaumcraft.common.blocks.BlockTaintFibres".equals(srgName)) {
+            ClassReader reader = new ClassReader(bytes);
+            ClassWriter writer = new ClassWriter(reader, Opcodes.ASM4);
+
+            ClassVisitor visitor = new ClassVisitor(Opcodes.ASM4, writer) {
+                @Override
+                public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
+                    MethodVisitor methodVisitor = super.visitMethod(access, name, desc, signature, exceptions);
+
+                    if("taintBiomeSpread".equals(name)) {
+                        return new BlockTaintFibersGeneratorAdapter(methodVisitor, access, name, desc);
+                    }
+
+                    return methodVisitor;
+                }
+            };
+
+            reader.accept(visitor, ClassReader.EXPAND_FRAMES);
+
+            bytes = writer.toByteArray();
+        }
+
+        return bytes;
+    }
+}
diff --git a/src/main/java/myessentials/event/ModifyBiomeEvent.java b/src/main/java/myessentials/event/ModifyBiomeEvent.java
new file mode 100644
index 0000000..fced4d0
--- /dev/null
+++ b/src/main/java/myessentials/event/ModifyBiomeEvent.java
@@ -0,0 +1,30 @@
+package myessentials.event;
+
+import cpw.mods.fml.common.eventhandler.Cancelable;
+import cpw.mods.fml.common.eventhandler.Event;
+import net.minecraft.block.Block;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraft.world.World;
+
+/**
+ * Fired when a biome is about to be modified.
+ * If the event is canceled the biome is not modified.
+ */
+@Cancelable
+public class ModifyBiomeEvent extends Event 
+{
+    public final int x;
+    public final int z;
+    public final World world;
+
+    public ModifyBiomeEvent(World world, int x, int z) {
+        this.x = x;
+        this.z = z;
+        this.world = world;
+    }
+
+    @SuppressWarnings("unused")
+    public static boolean checkBiome(World world, int x, int z) {
+        return MinecraftForge.EVENT_BUS.post(new ModifyBiomeEvent(world, x, z));
+    }
+}