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 5ed6599d1f9a2edf8c904f3602b06d26d857600c..b3c993a790fc3fab6a408c731deb297f74c959ce 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
@@ -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/src/main/java/net/minecraft/world/entity/EntityType.java b/src/main/java/net/minecraft/world/entity/EntityType.java
index e56050bef4a5aaa0fca17192dab4cf5e6a55fbae..3a8af3c6164da68eac0faeb436b8d9d8159fd4bd 100644
--- a/src/main/java/net/minecraft/world/entity/EntityType.java
+++ b/src/main/java/net/minecraft/world/entity/EntityType.java
@@ -715,9 +715,20 @@ 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, reason, (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 16ca1c8672e5f0a27f8a30498c754a81cdec5191..356d010506fd21f3c752e4aa86c46c1106fdde3b 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
@@ -93,7 +93,18 @@ 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);