From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Wed, 18 Nov 2020 20:52:25 -0800
Subject: [PATCH] Entity load/save limit per chunk

Adds a config option to limit the number of entities saved and loaded
to a chunk. The default values of -1 disable the limit. Although
defaults are only included for certain entites, this allows setting
limits for any entity type.

diff --git a/src/main/java/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java b/src/main/java/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java
index 19672631d7c69ade16a6f966c72a4a9d57b77c55..df4aadd40c0033c852af575fd11dce8eb3f2959e 100644
--- a/src/main/java/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java
+++ b/src/main/java/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java
@@ -100,7 +100,18 @@ public final class ChunkEntitySlices {
         }
 
         final ListTag entitiesTag = new ListTag();
+        final java.util.Map<net.minecraft.world.entity.EntityType<?>, Integer> savedEntityCounts = new java.util.HashMap<>(); // Paper - Entity load/save limit per chunk
         for (final Entity entity : entities) {
+            // Paper start - Entity load/save limit per chunk
+            final EntityType<?> entityType = entity.getType();
+            final int saveLimit = world.paperConfig().chunks.entityPerChunkSaveLimit.getOrDefault(entityType, -1);
+            if (saveLimit > -1) {
+                if (savedEntityCounts.getOrDefault(entityType, 0) >= saveLimit) {
+                    break;
+                }
+                savedEntityCounts.merge(entityType, 1, Integer::sum);
+            }
+            // Paper end - Entity load/save limit per chunk
             CompoundTag compoundTag = new CompoundTag();
             if (entity.save(compoundTag)) {
                 entitiesTag.add(compoundTag);
diff --git a/src/main/java/net/minecraft/world/entity/EntityType.java b/src/main/java/net/minecraft/world/entity/EntityType.java
index 842b0cec0397d7ae5166617627340ffac0e35db1..cb61462d4691a055a4b25f7b953609d8a154fdfe 100644
--- a/src/main/java/net/minecraft/world/entity/EntityType.java
+++ b/src/main/java/net/minecraft/world/entity/EntityType.java
@@ -649,9 +649,20 @@ public class EntityType<T extends Entity> implements FeatureElement, EntityTypeT
         final Spliterator<? extends Tag> spliterator = entityNbtList.spliterator();
 
         return StreamSupport.stream(new Spliterator<Entity>() {
+            final java.util.Map<EntityType<?>, Integer> loadedEntityCounts = new java.util.HashMap<>(); // Paper - Entity load/save limit per chunk
             public boolean tryAdvance(Consumer<? super Entity> consumer) {
                 return spliterator.tryAdvance((nbtbase) -> {
                     EntityType.loadEntityRecursive((CompoundTag) nbtbase, world, (entity) -> {
+                        // Paper start - Entity load/save limit per chunk
+                        final EntityType<?> entityType = entity.getType();
+                        final int saveLimit = world.paperConfig().chunks.entityPerChunkSaveLimit.getOrDefault(entityType, -1);
+                        if (saveLimit > -1) {
+                            if (this.loadedEntityCounts.getOrDefault(entityType, 0) >= saveLimit) {
+                                return null;
+                            }
+                            this.loadedEntityCounts.merge(entityType, 1, Integer::sum);
+                        }
+                        // Paper end - Entity load/save limit per chunk
                         consumer.accept(entity);
                         return entity;
                     });
diff --git a/src/main/java/net/minecraft/world/level/chunk/storage/EntityStorage.java b/src/main/java/net/minecraft/world/level/chunk/storage/EntityStorage.java
index 503ac0374e0c9f9993ad37bb8bd8cf1570d3615a..d4a505ef4af9ded02aeb1a817bcbe5b1a912a5b3 100644
--- a/src/main/java/net/minecraft/world/level/chunk/storage/EntityStorage.java
+++ b/src/main/java/net/minecraft/world/level/chunk/storage/EntityStorage.java
@@ -92,7 +92,18 @@ public class EntityStorage implements EntityPersistentStorage<Entity> {
             }
         } else {
             ListTag listTag = new ListTag();
+            final java.util.Map<net.minecraft.world.entity.EntityType<?>, Integer> savedEntityCounts = new java.util.HashMap<>(); // Paper - Entity load/save limit per chunk
             dataList.getEntities().forEach(entity -> {
+                // Paper start - Entity load/save limit per chunk
+                final EntityType<?> entityType = entity.getType();
+                final int saveLimit = this.level.paperConfig().chunks.entityPerChunkSaveLimit.getOrDefault(entityType, -1);
+                if (saveLimit > -1) {
+                    if (savedEntityCounts.getOrDefault(entityType, 0) >= saveLimit) {
+                        return;
+                    }
+                    savedEntityCounts.merge(entityType, 1, Integer::sum);
+                }
+                // Paper end - Entity load/save limit per chunk
                 CompoundTag compoundTagx = new CompoundTag();
                 if (entity.save(compoundTagx)) {
                     listTag.add(compoundTagx);