From a712ddf77ea7d2397deccb4fe233072b5926649f 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.

diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index a3c53d9dbf..3b745b2b75 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -739,7 +739,7 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
         // Spigot start
         if (org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly) {
             LOGGER.info("Saving usercache.json");
-            this.getUserCache().c();
+            this.getUserCache().c(false); // Paper
         }
         // Spigot end
     }
diff --git a/src/main/java/net/minecraft/server/UserCache.java b/src/main/java/net/minecraft/server/UserCache.java
index 41be5bf64e..cd8a652eb6 100644
--- a/src/main/java/net/minecraft/server/UserCache.java
+++ b/src/main/java/net/minecraft/server/UserCache.java
@@ -108,7 +108,7 @@ public class UserCache {
         this.a(gameprofile, (Date) null);
     }
 
-    private void a(GameProfile gameprofile, Date date) {
+    private synchronized void a(GameProfile gameprofile, Date date) { // Paper - synchronize
         UUID uuid = gameprofile.getId();
 
         if (date == null) {
@@ -121,8 +121,9 @@ public class UserCache {
 
         UserCache.UserCacheEntry usercache_usercacheentry = new UserCache.UserCacheEntry(gameprofile, date);
 
-        if (this.e.containsKey(uuid)) {
+        //if (this.e.containsKey(uuid)) { // Paper
             UserCache.UserCacheEntry usercache_usercacheentry1 = (UserCache.UserCacheEntry) this.e.get(uuid);
+        if (usercache_usercacheentry1 != null) { // Paper
 
             this.d.remove(usercache_usercacheentry1.a().getName().toLowerCase(Locale.ROOT));
             this.f.remove(gameprofile);
@@ -135,7 +136,7 @@ public class UserCache {
     }
 
     @Nullable
-    public GameProfile getProfile(String s) {
+    public synchronized GameProfile getProfile(String s) { // Paper - synchronize
         String s1 = s.toLowerCase(Locale.ROOT);
         UserCache.UserCacheEntry usercache_usercacheentry = (UserCache.UserCacheEntry) this.d.get(s1);
 
@@ -164,8 +165,9 @@ public class UserCache {
         return usercache_usercacheentry == null ? null : usercache_usercacheentry.a();
     }
 
+    @Nullable public GameProfile getProfile(UUID uuid) { return a(uuid);  } // Paper - OBFHELPER
     @Nullable
-    public GameProfile a(UUID uuid) {
+    public synchronized GameProfile a(UUID uuid) { // Paper - synchronize
         UserCache.UserCacheEntry usercache_usercacheentry = (UserCache.UserCacheEntry) this.e.get(uuid);
 
         return usercache_usercacheentry == null ? null : usercache_usercacheentry.a();
@@ -220,8 +222,15 @@ public class UserCache {
 
     }
 
+    // Paper start
     public void c() {
+        c(true);
+    }
+    public void c(boolean asyncSave) {
+        // Paper end
         String s = this.b.toJson(this.a(org.spigotmc.SpigotConfig.userCacheCap));
+        Runnable save = () -> {
+
         BufferedWriter bufferedwriter = null;
 
         try {
@@ -235,6 +244,14 @@ public class UserCache {
         } finally {
             IOUtils.closeQuietly(bufferedwriter);
         }
+        // Paper start
+        };
+        if (asyncSave) {
+            MCUtil.scheduleAsyncTask(save);
+        } else {
+            save.run();
+        }
+        // Paper end
 
     }
 
-- 
2.21.0