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/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java b/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java
index 1c82dcd38f789707e15e8cbec72ef9cdc7efdf56..ba20e87d2105ce53cdaf4049de2388d05fcd1b56 100644
--- a/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java
+++ b/ca/spottedleaf/moonrise/patches/chunk_system/level/entity/ChunkEntitySlices.java
@@ -104,7 +104,18 @@ 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 : PlatformHooks.get().modifySavedEntities(world, chunkPos.x, chunkPos.z, 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) {
+                    continue;
+                }
+                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/net/minecraft/world/entity/EntityType.java b/net/minecraft/world/entity/EntityType.java
index 4c57990c94721dd0973477669e1dadfab5f16404..8af02ed823da098a5592ef195c9fe8ed8f245b53 100644
--- a/net/minecraft/world/entity/EntityType.java
+++ b/net/minecraft/world/entity/EntityType.java
@@ -1430,9 +1430,20 @@ public class EntityType<T extends Entity> implements FeatureElement, EntityTypeT
     }
 
     public static Stream<Entity> loadEntitiesRecursive(List<? extends Tag> entityTags, Level level, EntitySpawnReason spawnReason) {
+        final java.util.Map<EntityType<?>, Integer> loadedEntityCounts = new java.util.HashMap<>(); // Paper - Entity load/save limit per chunk
         return entityTags.stream()
             .flatMap(tag -> tag.asCompound().stream())
             .mapMulti((compoundTag, consumer) -> loadEntityRecursive(compoundTag, level, spawnReason, entity -> {
+                // Paper start - Entity load/save limit per chunk
+                final EntityType<?> entityType = entity.getType();
+                final int saveLimit = level.paperConfig().chunks.entityPerChunkSaveLimit.getOrDefault(entityType, -1);
+                if (saveLimit > -1) {
+                    if (loadedEntityCounts.getOrDefault(entityType, 0) >= saveLimit) {
+                        return null;
+                    }
+                    loadedEntityCounts.merge(entityType, 1, Integer::sum);
+                }
+                // Paper end - Entity load/save limit per chunk
                 consumer.accept(entity);
                 return entity;
             }));
diff --git a/net/minecraft/world/level/chunk/storage/EntityStorage.java b/net/minecraft/world/level/chunk/storage/EntityStorage.java
index bcc2a4081fac07c4579c3aabfe4353743f8cd876..f9fb1380be9cbe960127c208c65c19f770e50b6d 100644
--- a/net/minecraft/world/level/chunk/storage/EntityStorage.java
+++ b/net/minecraft/world/level/chunk/storage/EntityStorage.java
@@ -87,7 +87,18 @@ 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
             entities.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 compoundTag1 = new CompoundTag();
                 if (entity.save(compoundTag1)) {
                     listTag.add(compoundTag1);