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 beae8a57a0ce9b8e7d81619efe4c39d908869319..6b1926080eddf61ff9c0156a6846f7f0bcff1c2d 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -764,7 +764,7 @@ 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());
             }
         }
@@ -1095,7 +1095,7 @@ 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());
         }
     }
@@ -1242,7 +1242,7 @@ 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 a6463974c63e40afce0c6656122f6f918fdc089b..0f085618f6866bef1a526c6404f92e26f7bef0fd 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -217,7 +217,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player, PluginMessa
     private static final WeakHashMap<Plugin, WeakReference<Plugin>> pluginWeakReferences = new WeakHashMap<>();
     private static final net.kyori.adventure.text.Component DEFAULT_KICK_COMPONENT = net.kyori.adventure.text.Component.translatable("multiplayer.disconnect.kicked");
     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 long firstPlayed = 0;
     private long lastPlayed = 0;
@@ -2961,7 +2961,7 @@ 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;
             }