From 19f11ee62ed69aa3863a06e15e937a8d227e5cf3 Mon Sep 17 00:00:00 2001
From: FalsePattern <me@falsepattern.com>
Date: Fri, 7 Jun 2024 16:37:56 +0200
Subject: [PATCH] tiny asm fixes

---
 .../endlessids/asm/GameDataHooks.java         |  6 +++++
 .../asm/transformer/GameDataAccelerator.java  | 22 ++++++++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/falsepattern/endlessids/asm/GameDataHooks.java b/src/main/java/com/falsepattern/endlessids/asm/GameDataHooks.java
index a0981e7..3457650 100644
--- a/src/main/java/com/falsepattern/endlessids/asm/GameDataHooks.java
+++ b/src/main/java/com/falsepattern/endlessids/asm/GameDataHooks.java
@@ -20,10 +20,14 @@ public class GameDataHooks {
         return gameData.endlessIDsItemBlockCache;
     }
 
+    //Called by ASM
+    @SuppressWarnings("unused")
     public static void cacheItemBlock(ItemBlock itemBlock, GameData gameData) {
         forGameData(gameData).put(itemBlock.field_150939_a, new WeakReference<>(itemBlock));
     }
 
+    //Called by ASM
+    @SuppressWarnings("unused")
     public static ItemBlock fetchCachedItemBlock(Block block, GameData gameData) {
         var weakItem = forGameData(gameData).get(block);
         if (weakItem != null) {
@@ -32,6 +36,8 @@ public class GameDataHooks {
         return null;
     }
 
+    //Called by ASM
+    @SuppressWarnings("unused")
     public static Iterable<Item> fakeIterable() {
         return Collections.emptyList();
     }
diff --git a/src/main/java/com/falsepattern/endlessids/asm/transformer/GameDataAccelerator.java b/src/main/java/com/falsepattern/endlessids/asm/transformer/GameDataAccelerator.java
index 65dc43d..40ca3c0 100644
--- a/src/main/java/com/falsepattern/endlessids/asm/transformer/GameDataAccelerator.java
+++ b/src/main/java/com/falsepattern/endlessids/asm/transformer/GameDataAccelerator.java
@@ -1,5 +1,6 @@
 package com.falsepattern.endlessids.asm.transformer;
 
+import com.falsepattern.endlessids.asm.AsmTransformException;
 import com.falsepattern.endlessids.asm.IClassNodeTransformer;
 import com.falsepattern.endlessids.asm.IETransformer;
 import lombok.val;
@@ -71,19 +72,30 @@ public class GameDataAccelerator implements IClassNodeTransformer {
         var iter = method.instructions.iterator();
         while (iter.hasNext()) {
             var insn = iter.next();
-            if (!(insn instanceof FieldInsnNode))
+            if ((insn.getOpcode() != Opcodes.GETFIELD) && !(insn instanceof FieldInsnNode))
                 continue;
             var fieldInsn = (FieldInsnNode) insn;
             if (!(fieldInsn.owner.equals("cpw/mods/fml/common/registry/GameData") &&
                   fieldInsn.name.equals("iItemRegistry") &&
                   fieldInsn.desc.equals("Lcpw/mods/fml/common/registry/FMLControlledNamespacedRegistry;")))
                 continue;
-            iter.previous();
-            iter.previous();
             iter.remove();
-            iter.next();
+            {
+                val testInsn = iter.previous();
+                if (testInsn.getOpcode() != Opcodes.ALOAD || ((VarInsnNode)testInsn).var != 0)
+                    throw new AsmTransformException("Opcode assertion 1 failed!");
+            }
             iter.remove();
-            iter.next();
+            {
+                val testInsn = iter.next();
+                if (testInsn.getOpcode() != Opcodes.INVOKEVIRTUAL)
+                    throw new AsmTransformException("Opcodes assertion 2 failed!");
+
+                val testInvoke = (MethodInsnNode)testInsn;
+                if (!testInvoke.owner.equals("cpw/mods/fml/common/registry/FMLControlledNamespacedRegistry") ||
+                    !testInvoke.name.equals("typeSafeIterable"))
+                    throw new AsmTransformException("Opcodes assertion 3 failed!");
+            }
             iter.remove();
             iter.add(new VarInsnNode(Opcodes.ALOAD, 1));
             iter.add(new VarInsnNode(Opcodes.ALOAD, 0));