Fix PalettedContainer synchronization (#7663)

patches/server/Synchronize-PalettedContainer-instead-of-ThreadingDe.patch

@@ -1,13 +1,14 @@
 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Fri, 29 May 2020 20:29:02 -0400
-Subject: [PATCH] Synchronize PalettedContainer instead of ReentrantLock
+Subject: [PATCH] Synchronize PalettedContainer instead of
+ ThreadingDetector/Semaphore
 
 Mojang has flaws in their logic about chunks being concurrently
 wrote to. So we constantly see crashes around multiple threads writing.
 
 Additionally, java has optimized synchronization so well that its
-in many times faster than trying to manage read wrote locks for low
+in many times faster than trying to manage read write locks for low
 contention situations.
 
 And this is extremely a low contention situation.
@@ -17,7 +18,11 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 --- a/src/main/java/net/minecraft/world/level/chunk/PalettedContainer.java
 +++ b/src/main/java/net/minecraft/world/level/chunk/PalettedContainer.java
 @@ -0,0 +0,0 @@ public class PalettedContainer<T> implements PaletteResize<T> {
-     private final ThreadingDetector threadingDetector = new ThreadingDetector("PalettedContainer");
+     private final T @org.jetbrains.annotations.Nullable [] presetValues; // Paper - Anti-Xray - Add preset values
+     private volatile PalettedContainer.Data<T> data;
+     private final PalettedContainer.Strategy strategy;
+-    private final ThreadingDetector threadingDetector = new ThreadingDetector("PalettedContainer");
++    // private final ThreadingDetector threadingDetector = new ThreadingDetector("PalettedContainer"); // Paper - unused
  
      public void acquire() {
 -        this.threadingDetector.checkAndLock();
@@ -32,22 +37,31 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
      // Paper start - Anti-Xray - Add preset values
 @@ -0,0 +0,0 @@ public class PalettedContainer<T> implements PaletteResize<T> {
      }
-     // Paper end
  
--    public T getAndSet(int x, int y, int z, T value) {
-+    public synchronized T getAndSet(int x, int y, int z, T value) { // Paper - synchronize
-         this.acquire();
+     @Override
+-    public int onResize(int newBits, T object) {
++    public synchronized int onResize(int newBits, T object) { // Paper - synchronize
+         PalettedContainer.Data<T> data = this.data;
  
-         Object var5;
+         // Paper start - Anti-Xray - Add preset values
 @@ -0,0 +0,0 @@ public class PalettedContainer<T> implements PaletteResize<T> {
-         return this.data.palette.valueFor(j);
+         return this.getAndSet(this.strategy.getIndex(x, y, z), value);
      }
  
--    public void set(int x, int y, int z, T value) {
-+    public synchronized void set(int x, int y, int z, T value) { // Paper - synchronize
-         this.acquire();
+-    private T getAndSet(int index, T value) {
++    private synchronized T getAndSet(int index, T value) { // Paper - synchronize
+         int i = this.data.palette.idFor(value);
+         int j = this.data.storage.getAndSet(index, i);
+         return this.data.palette.valueFor(j);
+@@ -0,0 +0,0 @@ public class PalettedContainer<T> implements PaletteResize<T> {
  
-         try {
+     }
+ 
+-    private void set(int index, T value) {
++    private synchronized void set(int index, T value) { // Paper - synchronize
+         int i = this.data.palette.idFor(value);
+         this.data.storage.set(index, i);
+     }
 @@ -0,0 +0,0 @@ public class PalettedContainer<T> implements PaletteResize<T> {
          });
      }
@@ -67,15 +81,6 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
  
          try {
 @@ -0,0 +0,0 @@ public class PalettedContainer<T> implements PaletteResize<T> {
- 
-     }
- 
--    private static <T> DataResult<PalettedContainer<T>> read(IdMap<T> idList, PalettedContainer.Strategy provider, PalettedContainer.DiscData<T> serialized, T defaultValue, T @org.jetbrains.annotations.Nullable [] presetValues) { // Paper - Anti-Xray - Add preset values
-+    private synchronized static <T> DataResult<PalettedContainer<T>> read(IdMap<T> idList, PalettedContainer.Strategy provider, PalettedContainer.DiscData<T> serialized, T defaultValue, T @org.jetbrains.annotations.Nullable [] presetValues) { // Paper - Anti-Xray - Add preset values // Paper - synchronize
-         List<T> list = serialized.paletteEntries();
-         int i = provider.size();
-         int j = provider.calculateBitsForSerialization(idList, list.size());
-@@ -0,0 +0,0 @@ public class PalettedContainer<T> implements PaletteResize<T> {
          return DataResult.success(new PalettedContainer<>(idList, provider, configuration, bitStorage, list, defaultValue, presetValues)); // Paper - Anti-Xray - Add preset values
      }