From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: peaches94 <peachescu94@gmail.com>
Date: Sat, 2 Jul 2022 00:35:56 -0500
Subject: [PATCH] Multithreaded Tracker

Original license: GPL v3
Original project: https://github.com/Bloom-host/Petal

Original license: GPL v3
Original project: https://github.com/TECHNOVE/Airplane-Experimental

Co-authored-by: Paul Sauve <paul@technove.co>
Co-authored-by: Kevin Raneri <kevin.raneri@gmail.com>
Co-authored-by: HaHaWTH <102713261+HaHaWTH@users.noreply.github.com>
Co-authored-by: hayanesuru <hayanesuru@outlook.jp>

This patch refactored from original multithreaded tracker (Petal version),
and is derived from the Airplane fork by Paul Sauve, the tree is like:
Airplane -> Pufferfish(?) -> Petal -> Leaf

The core logic has beed reworked compared to the old one, can handle larger
scale situation better now.
Current impl includes many improvements and fixes we made, such as
plugin compat issues with some NPC plugins using real entity type,
e.g. Citizens.

However we still recommend to use those packet based NPC plugins,
e.g. ZNPC Plus, Adyeshach, Fancy NPC, etc.

diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 5e46428e5dd24c581c816125b52cb32de087d5f4..c11449da3a89221e5525c229e990577c91238dc2 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -762,7 +762,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         ChunkMap.TrackedEntity entityTracker = world.getChunkSource().chunkMap.entityMap.get(this.getEntityId());
 
         if (entityTracker != null) {
-            for (ServerPlayerConnection connection : entityTracker.seenBy) {
+            for (ServerPlayerConnection connection : entityTracker.seenBy()) { // Leaf - Multithreaded tracker
                 players.add(connection.getPlayer().getBukkitEntity());
             }
         }
@@ -1093,7 +1093,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
             return;
         }
 
-        for (final ServerPlayerConnection connection : entityTracker.seenBy) {
+        for (final ServerPlayerConnection connection : entityTracker.seenBy()) { // Leaf - Multithreaded tracker
             this.getHandle().resendPossiblyDesyncedEntityData(connection.getPlayer());
         }
     }
@@ -1240,7 +1240,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         }
 
         Set<org.bukkit.entity.Player> set = new java.util.HashSet<>(tracker.seenBy.size());
-        for (net.minecraft.server.network.ServerPlayerConnection connection : tracker.seenBy) {
+        for (net.minecraft.server.network.ServerPlayerConnection connection : tracker.seenBy()) { // Leaf - Multithreaded tracker
             set.add(connection.getPlayer().getBukkitEntity().getPlayer());
         }
         return set;
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 3149a45297b5cffd247238bb04d3035568de5c07..4880ed8eaa3966c9669addfc72d7eb4abf537260 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -227,7 +227,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player, PluginMessa
     private long lastPlayed = 0;
     private boolean hasPlayedBefore = false;
     private final ConversationTracker conversationTracker = new ConversationTracker();
-    private final Map<UUID, Set<WeakReference<Plugin>>> invertedVisibilityEntities = new it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap<>(); // SparklyPaper - optimize canSee checks
+    private final Map<UUID, Set<WeakReference<Plugin>>> invertedVisibilityEntities = org.dreeam.leaf.config.modules.async.MultithreadedTracker.enabled ? it.unimi.dsi.fastutil.objects.Object2ObjectMaps.synchronize(new it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap<>()) : new it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap<>(); // SparklyPaper - optimize canSee checks // Leaf - Multithreaded tracker
     private final Set<UUID> unlistedEntities = new HashSet<>(); // Paper - Add Listing API for Player
     private static final WeakHashMap<Plugin, WeakReference<Plugin>> pluginWeakReferences = new WeakHashMap<>();
     private int hash = 0;
@@ -2834,7 +2834,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player, PluginMessa
         Iterator<AttributeInstance> iterator = collection.iterator();
         while (iterator.hasNext()) {
             AttributeInstance genericInstance = iterator.next();
-            if (genericInstance.getAttribute() == Attributes.MAX_HEALTH) {
+            if (genericInstance != null && genericInstance.getAttribute() == Attributes.MAX_HEALTH) { // Leaf - Multithreaded tracker
                 iterator.remove();
                 break;
             }