From 7dd6aa2360ed101b083dbb4b44b60e3a8e104525 Mon Sep 17 00:00:00 2001
From: TheMode <themode@outlook.fr>
Date: Sun, 18 Apr 2021 01:55:35 +0200
Subject: [PATCH] Separate PerChunkThreadProvider from
 PerInstanceThreadProvider, support arbitrary ThreadProvider#findThread number

---
 .../net/minestom/server/UpdateManager.java    |  2 +-
 .../net/minestom/server/entity/Player.java    |  1 +
 .../server/thread/PerChunkThreadProvider.java | 20 +++++++++++++++++++
 .../thread/PerInstanceThreadProvider.java     | 12 ++++++-----
 .../server/thread/ThreadProvider.java         |  4 ++--
 5 files changed, 31 insertions(+), 8 deletions(-)
 create mode 100644 src/main/java/net/minestom/server/thread/PerChunkThreadProvider.java

diff --git a/src/main/java/net/minestom/server/UpdateManager.java b/src/main/java/net/minestom/server/UpdateManager.java
index 60b2c67ce..d12266a19 100644
--- a/src/main/java/net/minestom/server/UpdateManager.java
+++ b/src/main/java/net/minestom/server/UpdateManager.java
@@ -39,8 +39,8 @@ public final class UpdateManager {
 
     {
         // DEFAULT THREAD PROVIDER
-        //threadProvider = new PerGroupChunkProvider();
         threadProvider = new PerInstanceThreadProvider(4);
+        //threadProvider = new PerChunkThreadProvider(4);
     }
 
     /**
diff --git a/src/main/java/net/minestom/server/entity/Player.java b/src/main/java/net/minestom/server/entity/Player.java
index b961e8082..d683ef356 100644
--- a/src/main/java/net/minestom/server/entity/Player.java
+++ b/src/main/java/net/minestom/server/entity/Player.java
@@ -327,6 +327,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
             packet.process(this);
         }
 
+        //System.out.println(getAcquiredElement().getHandler().getBatchThread());
         Collection<Acquirable<Player>> players = new ArrayList<>();
         //if (username.equals("TheMode911"))
         for (Player p1 : MinecraftServer.getConnectionManager().getOnlinePlayers()) {
diff --git a/src/main/java/net/minestom/server/thread/PerChunkThreadProvider.java b/src/main/java/net/minestom/server/thread/PerChunkThreadProvider.java
new file mode 100644
index 000000000..ecc66166a
--- /dev/null
+++ b/src/main/java/net/minestom/server/thread/PerChunkThreadProvider.java
@@ -0,0 +1,20 @@
+package net.minestom.server.thread;
+
+import net.minestom.server.instance.Chunk;
+import net.minestom.server.utils.chunk.ChunkUtils;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Each {@link Chunk} gets assigned to a random thread.
+ */
+public class PerChunkThreadProvider extends ThreadProvider {
+
+    public PerChunkThreadProvider(int threadCount) {
+        super(threadCount);
+    }
+
+    @Override
+    public long findThread(@NotNull Chunk chunk) {
+        return ChunkUtils.getChunkIndex(chunk.getChunkX(), chunk.getChunkZ());
+    }
+}
diff --git a/src/main/java/net/minestom/server/thread/PerInstanceThreadProvider.java b/src/main/java/net/minestom/server/thread/PerInstanceThreadProvider.java
index 87c541f60..5fee99902 100644
--- a/src/main/java/net/minestom/server/thread/PerInstanceThreadProvider.java
+++ b/src/main/java/net/minestom/server/thread/PerInstanceThreadProvider.java
@@ -1,10 +1,12 @@
 package net.minestom.server.thread;
 
 import net.minestom.server.instance.Chunk;
+import net.minestom.server.instance.Instance;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.concurrent.ThreadLocalRandom;
-
+/**
+ * Each {@link Instance} gets assigned to a random thread.
+ */
 public class PerInstanceThreadProvider extends ThreadProvider {
 
     public PerInstanceThreadProvider(int threadCount) {
@@ -12,7 +14,7 @@ public class PerInstanceThreadProvider extends ThreadProvider {
     }
 
     @Override
-    public int findThread(@NotNull Chunk chunk) {
-        return ThreadLocalRandom.current().nextInt(getThreads().size());
+    public long findThread(@NotNull Chunk chunk) {
+        return System.identityHashCode(chunk.getInstance());
     }
-}
+}
\ No newline at end of file
diff --git a/src/main/java/net/minestom/server/thread/ThreadProvider.java b/src/main/java/net/minestom/server/thread/ThreadProvider.java
index 08d2fa34b..f04aa996f 100644
--- a/src/main/java/net/minestom/server/thread/ThreadProvider.java
+++ b/src/main/java/net/minestom/server/thread/ThreadProvider.java
@@ -57,10 +57,10 @@ public abstract class ThreadProvider {
      *
      * @param chunk the chunk
      */
-    public abstract int findThread(@NotNull Chunk chunk);
+    public abstract long findThread(@NotNull Chunk chunk);
 
     protected void addChunk(Chunk chunk) {
-        int threadId = findThread(chunk);
+        final int threadId = (int) (Math.abs(findThread(chunk)) % threads.size());
         BatchThread thread = threads.get(threadId);
         var chunks = threadChunkMap.computeIfAbsent(thread, batchThread -> ConcurrentHashMap.newKeySet());