Paper/Spigot-Server-Patches/Cache-World-Entity-Type-counts.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Colin Godsey <crgodsey@gmail.com>
Date: Wed, 8 Aug 2018 10:10:06 -0600
Subject: [PATCH] Cache World Entity Type counts

Optimizes mob spawning by keeping a count of entities by type

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldEntityList.java b/src/main/java/com/destroystokyo/paper/PaperWorldEntityList.java
new file mode 100644
index 0000000000..35104542c5
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldEntityList.java
@@ -0,0 +0,0 @@
+package com.destroystokyo.paper;
+
+import net.minecraft.server.Entity;
+import net.minecraft.server.EntityInsentient;
+import net.minecraft.server.EnumCreatureType;
+import net.minecraft.server.IAnimal;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.World;
+import net.minecraft.server.WorldServer;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+public class PaperWorldEntityList extends ArrayList<Entity> {
+
+    private final WorldServer world;
+    private final int[] entityCounts = new int[EnumCreatureType.values().length];
+
+
+    public PaperWorldEntityList(World world) {
+        this.world = (WorldServer) world;
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends Entity> c) {
+        for (Entity e : c) {
+            updateEntityCount(e, 1);
+        }
+
+        return super.addAll(c);
+    }
+
+    @Override
+    public boolean removeAll(Collection<?> c) {
+        for (Object e : c) {
+            if (e instanceof Entity && ((Entity) e).getWorld() == world) {
+                updateEntityCount((Entity) e, -1);
+            }
+        }
+
+        return super.removeAll(c);
+    }
+
+    @Override
+    public boolean add(Entity e) {
+        updateEntityCount(e, 1);
+
+        return super.add(e);
+    }
+
+    @Override
+    public Entity remove(int index) {
+        guard();
+        Entity entity = super.remove(index);
+        if (entity != null) updateEntityCount(entity, -1);
+        return entity;
+    }
+
+    @Override
+    public boolean remove(Object o) {
+        guard();
+        if (super.remove(o)) {
+            updateEntityCount((Entity) o, -1);
+            return true;
+        }
+        return false;
+    }
+
+    private void guard() {
+        if (world.guardEntityList) {
+            throw new java.util.ConcurrentModificationException();
+        }
+    }
+
+    public int getCreatureCount(EnumCreatureType type) {
+        return entityCounts[type.ordinal()];
+    }
+
+    private void updateEntityCount(EnumCreatureType type, int amt) {
+        int count = entityCounts[type.ordinal()];
+
+        count += amt;
+
+        if (count < 0) {
+            MinecraftServer.LOGGER.error("Paper - Entity count cache has gone negative");
+            count = 0;
+        }
+
+        entityCounts[type.ordinal()] = count;
+    }
+
+    public void updateEntityCount(Entity entity, int amt) {
+        if (!(entity instanceof IAnimal)) return;
+
+        if (entity instanceof EntityInsentient) {
+            EntityInsentient entityinsentient = (EntityInsentient) entity;
+            if (amt > 0 && entityinsentient.isDespawnableByDefault() && entityinsentient.isPersistent()) {
+                return;
+            }
+        }
+        if (amt < 0) {
+            if (!entity.hasBeenCounted) {
+                return;
+            }
+            // Only remove once, we remove from if the entity list is guarded, but may be called later
+            entity.hasBeenCounted = false;
+        } else {
+            if (entity.hasBeenCounted) {
+                return;
+            }
+            entity.hasBeenCounted = true;
+        }
+
+        for (EnumCreatureType type : EnumCreatureType.values()) {
+            if (type.matches(entity)) {
+                updateEntityCount(type, amt);
+                break;
+            }
+        }
+    }
+}
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 4252e8c02a..2b1affd03c 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -0,0 +0,0 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
     private boolean az;
     public boolean dead;
     public boolean shouldBeRemoved; // Paper
+    public boolean hasBeenCounted = false; // Paper
     public float width;
     public float length;
     public float J;
diff --git a/src/main/java/net/minecraft/server/EntityInsentient.java b/src/main/java/net/minecraft/server/EntityInsentient.java
index 141db48f16..56542d531a 100644
--- a/src/main/java/net/minecraft/server/EntityInsentient.java
+++ b/src/main/java/net/minecraft/server/EntityInsentient.java
@@ -0,0 +0,0 @@ public abstract class EntityInsentient extends EntityLiving {
         return true;
     }
 
+    public boolean isDespawnableByDefault() { return isTypeNotPersistent(); } // Paper - sortof an obf helper, too annoying to change visibility here
     protected boolean isTypeNotPersistent() {
         return true;
     }
diff --git a/src/main/java/net/minecraft/server/EnumCreatureType.java b/src/main/java/net/minecraft/server/EnumCreatureType.java
index 8874a05be5..0af387c059 100644
--- a/src/main/java/net/minecraft/server/EnumCreatureType.java
+++ b/src/main/java/net/minecraft/server/EnumCreatureType.java
@@ -0,0 +0,0 @@ public enum EnumCreatureType {
         this.h = flag1;
     }
 
+    public boolean matches(Entity entity) { return innerClass().isAssignableFrom(entity.getClass()); } // Paper
+    public Class<? extends IAnimal> innerClass() { return this.a(); } // Paper - OBFHELPER
     public Class<? extends IAnimal> a() {
         return this.e;
     }
diff --git a/src/main/java/net/minecraft/server/SpawnerCreature.java b/src/main/java/net/minecraft/server/SpawnerCreature.java
index 32808558bb..62b4c64f68 100644
--- a/src/main/java/net/minecraft/server/SpawnerCreature.java
+++ b/src/main/java/net/minecraft/server/SpawnerCreature.java
@@ -0,0 +0,0 @@ public final class SpawnerCreature {
 
                 if ((!enumcreaturetype.c() || flag1) && (enumcreaturetype.c() || flag) && (!enumcreaturetype.d() || flag2)) {
                     k = limit * i / SpawnerCreature.b; // CraftBukkit - use per-world limits
-                    int l1 = worldserver.a(enumcreaturetype.a(), k);
+                    int l1 = worldserver.entityList.getCreatureCount(enumcreaturetype); // Paper - entity count cache
 
                     if (l1 <= k) {
                         BlockPosition.MutableBlockPosition blockposition_mutableblockposition = new BlockPosition.MutableBlockPosition();
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index f99cdf1003..c479828d49 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -0,0 +0,0 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
     private static final EnumDirection[] a = EnumDirection.values();
     private int b = 63;
     // Spigot start - guard entity list from removals
-    public final List<Entity> entityList = new java.util.ArrayList<Entity>()
+    public final com.destroystokyo.paper.PaperWorldEntityList entityList = new com.destroystokyo.paper.PaperWorldEntityList(this);
+        /* // Paper start
     {
         @Override
         public Entity remove(int index)
@@ -0,0 +0,0 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
             }
         }
     };
+    */ // Paper end
     // Spigot end
     protected final Set<Entity> g = com.google.common.collect.Sets.newHashSet(); public Set<Entity> getEntityUnloadQueue() { return g; };// Paper - OBFHELPER
     //public final List<TileEntity> tileEntityList = Lists.newArrayList(); // Paper - remove unused list
@@ -0,0 +0,0 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
     public final com.destroystokyo.paper.PaperWorldConfig paperConfig; // Paper
 
     public final co.aikar.timings.WorldTimingsHandler timings; // Paper
-    private boolean guardEntityList; // Spigot
+    public boolean guardEntityList; // Spigot // Paper - public
     public static boolean haveWeSilencedAPhysicsCrash;
     public static String blockLocation;
     private org.spigotmc.TickLimiter entityLimiter;
@@ -0,0 +0,0 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
             this.getChunkAt(i, j).b(entity);
         }
         entity.shouldBeRemoved = true; // Paper
+        entityList.updateEntityCount(entity, -1); // Paper
 
         if (!guardEntityList) { // Spigot - It will get removed after the tick if we are ticking // Paper - always remove from current chunk above
         // CraftBukkit start - Decrement loop variable field if we've already ticked this entity
--