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.

diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 3b2fcb4338d56a8e1dd2de799571db4e2a79ec9f..c6ab645397911d984a28e40583bdb8f782a4f934 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -896,7 +896,7 @@ public abstract class MinecraftServer extends IAsyncTaskHandlerReentrant<TickTas
         } catch (java.lang.InterruptedException ignored) {} // Paper
         if (org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly) {
             LOGGER.info("Saving usercache.json");
-            this.getUserCache().b();
+            this.getUserCache().b(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 faf4d00bf288359db806913c4d2964324e8706b7..8ae72e8c8325d9b03803f29fcdd83a0ce8d34450 100644
--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
@@ -251,7 +251,7 @@ public class DedicatedServer extends MinecraftServer implements IMinecraftServer
         }
 
         if (this.convertNames()) {
-            this.getUserCache().b();
+            this.getUserCache().b(false); // Paper
         }
 
         if (!NameReferencingFileConverter.e(this)) {
diff --git a/src/main/java/net/minecraft/server/players/UserCache.java b/src/main/java/net/minecraft/server/players/UserCache.java
index 581e036f598b51a4e9f2dafd7e92c700c3e04407..9bb949ff4cbfc87ce179653939454a1e44dcdd77 100644
--- a/src/main/java/net/minecraft/server/players/UserCache.java
+++ b/src/main/java/net/minecraft/server/players/UserCache.java
@@ -107,7 +107,7 @@ public class UserCache {
         return UserCache.b;
     }
 
-    public void a(GameProfile gameprofile) {
+    public synchronized void a(GameProfile gameprofile) { // Paper - synchronize
         Calendar calendar = Calendar.getInstance();
 
         calendar.setTime(new Date());
@@ -116,7 +116,7 @@ public class UserCache {
         UserCache.UserCacheEntry usercache_usercacheentry = new UserCache.UserCacheEntry(gameprofile, date);
 
         this.a(usercache_usercacheentry);
-        if( !org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly ) this.b(); // Spigot - skip saving if disabled
+        if( !org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly ) this.b(true); // Spigot - skip saving if disabled // Paper - async
     }
 
     private long d() {
@@ -124,7 +124,7 @@ 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.c.get(s1);
         boolean flag = false;
@@ -150,7 +150,7 @@ public class UserCache {
         }
 
         if (flag && !org.spigotmc.SpigotConfig.saveUserCacheOnStopOnly) { // Spigot - skip saving if disabled
-            this.b();
+            this.b(true); // Paper
         }
 
         return gameprofile;
@@ -232,7 +232,7 @@ public class UserCache {
         return arraylist;
     }
 
-    public void b() {
+    public void b(boolean asyncSave) { // Paper
         JsonArray jsonarray = new JsonArray();
         DateFormat dateformat = e();
 
@@ -240,6 +240,7 @@ public class UserCache {
             jsonarray.add(a(usercache_usercacheentry, dateformat));
         });
         String s = this.f.toJson(jsonarray);
+        Runnable save = () -> { // Paper
 
         try {
             BufferedWriter bufferedwriter = Files.newWriter(this.g, StandardCharsets.UTF_8);
@@ -267,6 +268,14 @@ public class UserCache {
         } catch (IOException ioexception) {
             ;
         }
+        // Paper start
+        };
+        if (asyncSave) {
+            MCUtil.scheduleAsyncTask(save);
+        } else {
+            save.run();
+        }
+        // Paper end
 
     }