From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Hugo Planque <hookwood01@gmail.com>
Date: Thu, 21 Jan 2021 17:56:03 +0100
Subject: [PATCH] New NBT cache

Original code by YatopiaMC, licensed under MIT
You can find the original code on https://github.com/YatopiaMC/Yatopia

diff --git a/src/main/java/net/minecraft/world/level/storage/PlayerDataStorage.java b/src/main/java/net/minecraft/world/level/storage/PlayerDataStorage.java
index b470da69f271d1a5ebb9727c0c34944e85ce3a51..5e80825c0e98c0eb5c4309a9234e7b03d2d383db 100644
--- a/src/main/java/net/minecraft/world/level/storage/PlayerDataStorage.java
+++ b/src/main/java/net/minecraft/world/level/storage/PlayerDataStorage.java
@@ -24,6 +24,7 @@ public class PlayerDataStorage {
     private static final Logger LOGGER = LogManager.getLogger();
     private final File playerDir;
     protected final DataFixer fixerUpper;
+    private final wtf.etil.mirai.server.cache.NBTCache dataCache = new wtf.etil.mirai.server.cache.NBTCache(); // Mirai - NBT Cache system
 
     public PlayerDataStorage(LevelStorageSource.LevelStorageAccess session, DataFixer dataFixer) {
         this.fixerUpper = dataFixer;
@@ -37,11 +38,24 @@ public class PlayerDataStorage {
             CompoundTag nbttagcompound = player.saveWithoutId(new CompoundTag());
             File file = File.createTempFile(player.getStringUUID() + "-", ".dat", this.playerDir);
 
-            NbtIo.writeCompressed(nbttagcompound, file);
-            File file1 = new File(this.playerDir, player.getStringUUID() + ".dat");
-            File file2 = new File(this.playerDir, player.getStringUUID() + ".dat_old");
+            // Mirai start - NBT Cache system
+            Runnable task = () -> {
+                try {
+                    NbtIo.writeCompressed(nbttagcompound, file);
+                    File file1 = new File(this.playerDir, player.getStringUUID() + ".dat");
+                    File file2 = new File(this.playerDir, player.getStringUUID() + ".dat_old");
+
+                    Util.safeReplaceFile(file1, file, file2);
+                } catch (Exception exception) {
+                    PlayerDataStorage.LOGGER.error("Failed to save player data for {}", player.getScoreboardName(), exception); // Paper
+                }
+            };
+            synchronized (this.dataCache){
+                this.dataCache.put(file, nbttagcompound);
+            }
+            net.minecraft.server.MCUtil.asyncExecutor.execute(task);
+            // Mirai end
 
-            Util.safeReplaceFile(file1, file, file2);
         } catch (Exception exception) {
             PlayerDataStorage.LOGGER.warn("Failed to save player data for {}", player.getScoreboardName(), exception); // Paper
         }
@@ -56,9 +70,18 @@ public class PlayerDataStorage {
             File file = new File(this.playerDir, player.getStringUUID() + ".dat");
             // Spigot Start
             boolean usingWrongFile = false;
-            if ( org.bukkit.Bukkit.getOnlineMode() && !file.exists() ) // Paper - Check online mode first
+            // Mirai start - NBT Cache system
+            boolean normalFile = file.exists() && file.isFile();
+            CompoundTag playerData;
+            synchronized (this.dataCache){
+                playerData = this.dataCache.get(file);
+            }
+            if (playerData == null && org.bukkit.Bukkit.getOnlineMode() && !normalFile ) // Paper - Check online mode first
             {
                 file = new File( this.playerDir, java.util.UUID.nameUUIDFromBytes( ( "OfflinePlayer:" + player.getScoreboardName() ).getBytes( "UTF-8" ) ).toString() + ".dat");
+                synchronized (this.dataCache){
+                    playerData = this.dataCache.get(file);
+                }
                 if ( file.exists() )
                 {
                     usingWrongFile = true;
@@ -67,9 +90,12 @@ public class PlayerDataStorage {
             }
             // Spigot End
 
-            if (file.exists() && file.isFile()) {
+            if (playerData != null) {
+                nbttagcompound = playerData;
+            } else if (normalFile) {
                 nbttagcompound = NbtIo.readCompressed(file);
             }
+            // Mirai end
             // Spigot Start
             if ( usingWrongFile )
             {
diff --git a/src/main/java/wtf/etil/mirai/server/cache/NBTCache.java b/src/main/java/wtf/etil/mirai/server/cache/NBTCache.java
new file mode 100644
index 0000000000000000000000000000000000000000..10be297ed6e7aaa963d5bdcd40a589e877884cf7
--- /dev/null
+++ b/src/main/java/wtf/etil/mirai/server/cache/NBTCache.java
@@ -0,0 +1,32 @@
+package wtf.etil.mirai.server.cache;
+
+import it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenCustomHashMap;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.nbt.CompoundTag;
+
+import java.io.File;
+
+public class NBTCache extends Object2ObjectLinkedOpenCustomHashMap<File, CompoundTag> {
+
+    public NBTCache() {
+        super(100, 0.75F, new Strategy<File>() {
+            @Override
+            public int hashCode(File k) {
+                return k.hashCode();
+            }
+
+            @Override
+            public boolean equals(File k, File k1) {
+                return k.equals(k1);
+            }
+        });
+    }
+
+    @Override
+    public CompoundTag put(File k, CompoundTag v) {
+        if (this.size() > MinecraftServer.getServer().getPlayerCount()) {
+            this.removeLast();
+        }
+        return super.putAndMoveToFirst(k, v);
+    }
+}
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