From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 16 May 2016 20:47:41 -0400
Subject: [PATCH] Optimize UserCache / Thread Safe

Because Techable keeps complaining about how this isn't thread safe,
easier to do this than replace the entire thing.

Additionally, move Saving of the User cache to be done async, incase
the user never changed the default setting for Spigot's save on stop only.

1.17: TODO does this need the synchronized blocks anymore?

diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 623a2cf6b6e05598124014c7340590d26c7880b8..79270b3969c6c05a5a90756a88f3547b64cf5f3b 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -988,7 +988,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
         } catch (java.lang.InterruptedException ignored) {} // Paper
         if (org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly) {
             MinecraftServer.LOGGER.info("Saving usercache.json");
-            this.getProfileCache().save();
+            this.getProfileCache().save(false); // Paper
         }
         // Spigot end
 
diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
index bd94277862e0f5546b4df81fbd535d2e4c7ef5b1..7d834c1b1588851188372eebd9efad9313c610f7 100644
--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
@@ -257,7 +257,7 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
         }
 
         if (this.convertOldUsers()) {
-            this.getProfileCache().save();
+            this.getProfileCache().save(false); // Paper
         }
 
         if (!OldUsersConverter.serverReadyAfterUserconversion(this)) {
diff --git a/src/main/java/net/minecraft/server/players/GameProfileCache.java b/src/main/java/net/minecraft/server/players/GameProfileCache.java
index 769f2a595f8ca6030c17d5472ee1773063ebe52c..548627b5a12e79ac31136b2695e45f9452115348 100644
--- a/src/main/java/net/minecraft/server/players/GameProfileCache.java
+++ b/src/main/java/net/minecraft/server/players/GameProfileCache.java
@@ -118,7 +118,7 @@ public class GameProfileCache {
         return GameProfileCache.usesAuthentication;
     }
 
-    public void add(GameProfile profile) {
+    public synchronized void add(GameProfile profile) { // Paper - synchronize
         Calendar calendar = Calendar.getInstance();
 
         calendar.setTime(new Date());
@@ -127,14 +127,14 @@ public class GameProfileCache {
         GameProfileCache.GameProfileInfo usercache_usercacheentry = new GameProfileCache.GameProfileInfo(profile, date);
 
         this.safeAdd(usercache_usercacheentry);
-        if( !org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly ) this.save(); // Spigot - skip saving if disabled
+        if( !org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly ) this.save(true); // Spigot - skip saving if disabled // Paper - async
     }
 
     private long getNextOperation() {
         return this.operationCount.incrementAndGet();
     }
 
-    public Optional<GameProfile> get(String name) {
+    public synchronized Optional<GameProfile> get(String name) { // Paper - synchronize
         String s1 = name.toLowerCase(Locale.ROOT);
         GameProfileCache.GameProfileInfo usercache_usercacheentry = (GameProfileCache.GameProfileInfo) this.profilesByName.get(s1);
         boolean flag = false;
@@ -160,7 +160,7 @@ public class GameProfileCache {
         }
 
         if (flag && !org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly) { // Spigot - skip saving if disabled
-            this.save();
+            this.save(true); // Paper
         }
 
         return optional;
@@ -270,7 +270,7 @@ public class GameProfileCache {
         return arraylist;
     }
 
-    public void save() {
+    public void save(boolean asyncSave) { // Paper
         JsonArray jsonarray = new JsonArray();
         DateFormat dateformat = GameProfileCache.createDateFormat();
 
@@ -278,6 +278,7 @@ public class GameProfileCache {
             jsonarray.add(GameProfileCache.writeGameProfile(usercache_usercacheentry, dateformat));
         });
         String s = this.gson.toJson(jsonarray);
+        Runnable save = () -> { // Paper
 
         try {
             BufferedWriter bufferedwriter = Files.newWriter(this.file, StandardCharsets.UTF_8);
@@ -302,7 +303,14 @@ public class GameProfileCache {
         } catch (IOException ioexception) {
             ;
         }
-
+        // Paper start
+        };
+        if (asyncSave) {
+            net.minecraft.server.MCUtil.scheduleAsyncTask(save);
+        } else {
+            save.run();
+        }
+        // Paper end
     }
 
     private Stream<GameProfileCache.GameProfileInfo> getTopMRUProfiles(int limit) {