Fix GameProfileCache concurrency

Separate lookup and state access locks prevent lookups
from stalling simple state access/write calls

paper-server/patches/sources/net/minecraft/server/players/GameProfileCache.java.patch

@@ -1,6 +1,32 @@
 --- a/net/minecraft/server/players/GameProfileCache.java
 +++ b/net/minecraft/server/players/GameProfileCache.java
-@@ -85,10 +85,12 @@
+@@ -60,6 +60,11 @@
+     @Nullable
+     private Executor executor;
+ 
++    // Paper start - Fix GameProfileCache concurrency
++    protected final java.util.concurrent.locks.ReentrantLock stateLock = new java.util.concurrent.locks.ReentrantLock();
++    protected final java.util.concurrent.locks.ReentrantLock lookupLock = new java.util.concurrent.locks.ReentrantLock();
++    // Paper end - Fix GameProfileCache concurrency
++
+     public GameProfileCache(GameProfileRepository profileRepository, File cacheFile) {
+         this.profileRepository = profileRepository;
+         this.file = cacheFile;
+@@ -67,11 +72,13 @@
+     }
+ 
+     private void safeAdd(GameProfileCache.GameProfileInfo entry) {
++        try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
+         GameProfile gameprofile = entry.getProfile();
+ 
+         entry.setLastAccess(this.getNextOperation());
+         this.profilesByName.put(gameprofile.getName().toLowerCase(Locale.ROOT), entry);
+         this.profilesByUUID.put(gameprofile.getId(), entry);
++        } finally { this.stateLock.unlock(); } // Paper - Fix GameProfileCache concurrency
+     }
+ 
+     private static Optional<GameProfile> lookupGameProfile(GameProfileRepository repository, String name) {
+@@ -85,10 +92,12 @@
                  }
  
                  public void onProfileLookupFailed(String s1, Exception exception) {
@@ -14,7 +40,7 @@
              repository.findProfilesByNames(new String[]{name}, profilelookupcallback);
              GameProfile gameprofile = (GameProfile) atomicreference.get();
  
-@@ -105,7 +107,7 @@
+@@ -105,7 +114,7 @@
      }
  
      private static boolean usesAuthentication() {
@@ -23,7 +49,7 @@
      }
  
      public void add(GameProfile profile) {
-@@ -117,13 +119,24 @@
+@@ -117,15 +126,29 @@
          GameProfileCache.GameProfileInfo usercache_usercacheentry = new GameProfileCache.GameProfileInfo(profile, date);
  
          this.safeAdd(usercache_usercacheentry);
@@ -37,24 +63,34 @@
  
 +    // Paper start
 +    public @Nullable GameProfile getProfileIfCached(String name) {
++        try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
 +        GameProfileCache.GameProfileInfo entry = this.profilesByName.get(name.toLowerCase(Locale.ROOT));
 +        if (entry == null) {
 +            return null;
 +        }
 +        entry.setLastAccess(this.getNextOperation());
 +        return entry.getProfile();
++        } finally { this.stateLock.unlock(); } // Paper - Fix GameProfileCache concurrency
 +    }
 +    // Paper end
 +
      public Optional<GameProfile> get(String name) {
          String s1 = name.toLowerCase(Locale.ROOT);
++        boolean stateLocked = true; try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
          GameProfileCache.GameProfileInfo usercache_usercacheentry = (GameProfileCache.GameProfileInfo) this.profilesByName.get(s1);
-@@ -142,15 +155,15 @@
+         boolean flag = false;
+ 
+@@ -141,19 +164,24 @@
+         if (usercache_usercacheentry != null) {
              usercache_usercacheentry.setLastAccess(this.getNextOperation());
              optional = Optional.of(usercache_usercacheentry.getProfile());
++            stateLocked = false; this.stateLock.unlock(); // Paper - Fix GameProfileCache concurrency
          } else {
 -            optional = GameProfileCache.lookupGameProfile(this.profileRepository, s1);
++            stateLocked = false; this.stateLock.unlock(); // Paper - Fix GameProfileCache concurrency
++            try { this.lookupLock.lock(); // Paper - Fix GameProfileCache concurrency
 +            optional = GameProfileCache.lookupGameProfile(this.profileRepository, name); // CraftBukkit - use correct case for offline players
++            } finally { this.lookupLock.unlock(); } // Paper - Fix GameProfileCache concurrency
              if (optional.isPresent()) {
                  this.add((GameProfile) optional.get());
                  flag = false;
@@ -68,7 +104,11 @@
          }
  
          return optional;
-@@ -167,7 +180,7 @@
++        } finally { if (stateLocked) {  this.stateLock.unlock(); } } // Paper - Fix GameProfileCache concurrency
+     }
+ 
+     public CompletableFuture<Optional<GameProfile>> getAsync(String username) {
+@@ -167,7 +195,7 @@
              } else {
                  CompletableFuture<Optional<GameProfile>> completablefuture1 = CompletableFuture.supplyAsync(() -> {
                      return this.get(username);
@@ -77,7 +117,23 @@
                      this.requests.remove(username);
                  }, this.executor);
  
-@@ -208,7 +221,7 @@
+@@ -178,6 +206,7 @@
+     }
+ 
+     public Optional<GameProfile> get(UUID uuid) {
++        try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
+         GameProfileCache.GameProfileInfo usercache_usercacheentry = (GameProfileCache.GameProfileInfo) this.profilesByUUID.get(uuid);
+ 
+         if (usercache_usercacheentry == null) {
+@@ -186,6 +215,7 @@
+             usercache_usercacheentry.setLastAccess(this.getNextOperation());
+             return Optional.of(usercache_usercacheentry.getProfile());
+         }
++        } finally { this.stateLock.unlock(); } // Paper - Fix GameProfileCache concurrency
+     }
+ 
+     public void setExecutor(Executor executor) {
+@@ -208,7 +238,7 @@
  
              label54:
              {
@@ -86,7 +142,7 @@
  
                  try {
                      JsonArray jsonarray = (JsonArray) this.gson.fromJson(bufferedreader, JsonArray.class);
-@@ -217,7 +230,7 @@
+@@ -217,7 +247,7 @@
                          DateFormat dateformat = GameProfileCache.createDateFormat();
  
                          jsonarray.forEach((jsonelement) -> {
@@ -95,7 +151,7 @@
  
                              Objects.requireNonNull(list);
                              optional.ifPresent(list::add);
-@@ -250,6 +263,11 @@
+@@ -250,6 +280,11 @@
              }
          } catch (FileNotFoundException filenotfoundexception) {
              ;
@@ -107,7 +163,7 @@
          } catch (JsonParseException | IOException ioexception) {
              GameProfileCache.LOGGER.warn("Failed to load profile cache {}", this.file, ioexception);
          }
-@@ -257,14 +275,15 @@
+@@ -257,14 +292,15 @@
          return list;
      }
  
@@ -117,7 +173,7 @@
          DateFormat dateformat = GameProfileCache.createDateFormat();
  
 -        this.getTopMRUProfiles(1000).forEach((usercache_usercacheentry) -> {
-+        this.getTopMRUProfiles(org.spigotmc.SpigotConfig.userCacheCap).forEach((usercache_usercacheentry) -> { // Spigot
++        this.listTopMRUProfiles(org.spigotmc.SpigotConfig.userCacheCap).forEach((usercache_usercacheentry) -> { // Spigot // Paper - Fix GameProfileCache concurrency
              jsonarray.add(GameProfileCache.writeGameProfile(usercache_usercacheentry, dateformat));
          });
          String s = this.gson.toJson(jsonarray);
@@ -125,7 +181,7 @@
  
          try {
              BufferedWriter bufferedwriter = Files.newWriter(this.file, StandardCharsets.UTF_8);
-@@ -289,6 +308,14 @@
+@@ -289,13 +325,32 @@
          } catch (IOException ioexception) {
              ;
          }
@@ -140,3 +196,22 @@
  
      }
  
+     private Stream<GameProfileCache.GameProfileInfo> getTopMRUProfiles(int limit) {
+-        return ImmutableList.copyOf(this.profilesByUUID.values()).stream().sorted(Comparator.comparing(GameProfileCache.GameProfileInfo::getLastAccess).reversed()).limit((long) limit);
++        // Paper start - Fix GameProfileCache concurrency
++        return this.listTopMRUProfiles(limit).stream();
+     }
+ 
++    private List<GameProfileCache.GameProfileInfo> listTopMRUProfiles(int limit) {
++        try {
++            this.stateLock.lock();
++            return this.profilesByUUID.values().stream().sorted(Comparator.comparing(GameProfileCache.GameProfileInfo::getLastAccess).reversed()).limit(limit).toList();
++        } finally {
++            this.stateLock.unlock();
++        }
++    }
++    // Paper end - Fix GameProfileCache concurrency
++
+     private static JsonElement writeGameProfile(GameProfileCache.GameProfileInfo entry, DateFormat dateFormat) {
+         JsonObject jsonobject = new JsonObject();
+