Remove hot allocations in ForgeRegistry#getDelegateOrThrow

forge/src/main/java/org/embeddedt/modernfix/forge/mixin/perf/forge_registry_alloc/ForgeRegistryMixin.java

@@ -0,0 +1,65 @@
+package org.embeddedt.modernfix.forge.mixin.perf.forge_registry_alloc;
+
+import net.minecraft.core.Holder;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraftforge.registries.ForgeRegistry;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+import org.spongepowered.asm.mixin.Shadow;
+
+import java.util.Locale;
+import java.util.Map;
+
+@Mixin(value = ForgeRegistry.class, remap = false)
+public abstract class ForgeRegistryMixin<V> {
+    @Shadow @Final private Map<ResourceLocation, Holder.Reference<V>> delegatesByName;
+
+    @Shadow @Final private Map<V, Holder.Reference<V>> delegatesByValue;
+
+    /**
+     * @author embeddedt
+     * @reason stop allocating so many unneeded objects. stop.
+     */
+    @Overwrite
+    public Holder.Reference<V> getDelegateOrThrow(ResourceLocation location) {
+        Holder.Reference<V> holder = delegatesByName.get(location);
+
+        if (holder == null) {
+            throw new IllegalArgumentException(String.format(Locale.ENGLISH, "No delegate exists for location %s", location));
+        }
+
+        return holder;
+    }
+
+    /**
+     * @author embeddedt
+     * @reason see above
+     */
+    @Overwrite
+    public Holder.Reference<V> getDelegateOrThrow(ResourceKey<V> rkey) {
+        Holder.Reference<V> holder = delegatesByName.get(rkey.location());
+
+        if (holder == null) {
+            throw new IllegalArgumentException(String.format(Locale.ENGLISH, "No delegate exists for key %s", rkey));
+        }
+
+        return holder;
+    }
+
+    /**
+     * @author embeddedt
+     * @reason see above
+     */
+    @Overwrite
+    public Holder.Reference<V> getDelegateOrThrow(V value) {
+        Holder.Reference<V> holder = delegatesByValue.get(value);
+
+        if (holder == null) {
+            throw new IllegalArgumentException(String.format(Locale.ENGLISH, "No delegate exists for value %s", value));
+        }
+
+        return holder;
+    }
+}