From 1d60cdb4002cb4b4fd43f4911978d911ad3cb9f6 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 26 May 2024 08:37:34 -0700
Subject: [PATCH] Fix CME in StructureTemplate.Palette

The cache needs to be a CHM to prevent CMEs. Since the only usage
is compute() on static data, this is all we need to fix the
threading issues here.
---
 .../StructureTemplate$PaletteMixin.java       | 35 +++++++++++++++++++
 src/main/resources/moonrise.accesswidener     |  6 +++-
 src/main/resources/moonrise.mixins.json       |  1 +
 3 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/ca/spottedleaf/moonrise/mixin/chunk_system/StructureTemplate$PaletteMixin.java

diff --git a/src/main/java/ca/spottedleaf/moonrise/mixin/chunk_system/StructureTemplate$PaletteMixin.java b/src/main/java/ca/spottedleaf/moonrise/mixin/chunk_system/StructureTemplate$PaletteMixin.java
new file mode 100644
index 00000000..5e943b5f
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/moonrise/mixin/chunk_system/StructureTemplate$PaletteMixin.java
@@ -0,0 +1,35 @@
+package ca.spottedleaf.moonrise.mixin.chunk_system;
+
+import net.minecraft.world.level.block.Block;
+import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplate;
+import org.objectweb.asm.Opcodes;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+@Mixin(StructureTemplate.Palette.class)
+public abstract class StructureTemplate$PaletteMixin {
+
+    @Shadow
+    private Map<Block, List<StructureTemplate.StructureBlockInfo>> cache;
+
+    /**
+     * @reason Make cache CHM to prevent CME
+     * @author Spottedleaf
+     */
+    @Inject(
+            method = "<init>",
+            at = @At(
+                    value = "RETURN"
+            )
+    )
+    private <K, V> void makeCacheCHM(final CallbackInfo ci) {
+        this.cache = new ConcurrentHashMap<>();
+    }
+}
diff --git a/src/main/resources/moonrise.accesswidener b/src/main/resources/moonrise.accesswidener
index 10364af5..dd43b3c4 100644
--- a/src/main/resources/moonrise.accesswidener
+++ b/src/main/resources/moonrise.accesswidener
@@ -253,4 +253,8 @@ mutable field net/minecraft/client/multiplayer/ClientLevel entityStorage Lnet/mi
 
 # ClientLevel$EntityCallbacks
 accessible class net/minecraft/client/multiplayer/ClientLevel$EntityCallbacks
-accessible method net/minecraft/client/multiplayer/ClientLevel$EntityCallbacks <init> (Lnet/minecraft/client/multiplayer/ClientLevel;)V
\ No newline at end of file
+accessible method net/minecraft/client/multiplayer/ClientLevel$EntityCallbacks <init> (Lnet/minecraft/client/multiplayer/ClientLevel;)V
+
+
+# StructureTemplate$Palette
+mutable field net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate$Palette cache Ljava/util/Map;
\ No newline at end of file
diff --git a/src/main/resources/moonrise.mixins.json b/src/main/resources/moonrise.mixins.json
index 2fa10e2d..28dcf862 100644
--- a/src/main/resources/moonrise.mixins.json
+++ b/src/main/resources/moonrise.mixins.json
@@ -43,6 +43,7 @@
     "chunk_system.ServerPlayerMixin",
     "chunk_system.SortedArraySetMixin",
     "chunk_system.StructureCheckMixin",
+    "chunk_system.StructureTemplate$PaletteMixin",
     "chunk_system.TicketMixin",
     "collisions.ArmorStandMixin",
     "collisions.ArrayVoxelShapeMixin",