Cache permission lookups

sponge/src/main/java/me/lucko/luckperms/api/sponge/LuckPermsUserSubject.java

@@ -29,6 +29,7 @@ import me.lucko.luckperms.users.User;
 import org.spongepowered.api.service.context.Context;
 import org.spongepowered.api.util.Tristate;
 
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -44,11 +45,20 @@ public class LuckPermsUserSubject extends LuckPermsSubject {
     @Getter
     private final Map<String, Boolean> permissionCache = new ConcurrentHashMap<>();
 
+    @Getter
+    private final Map<String, Tristate> lookupCache = new HashMap<>();
+
     private LuckPermsUserSubject(User user, LuckPermsService service) {
         super(user, service);
         this.user = user;
     }
 
+    public void invalidateCache() {
+        synchronized (lookupCache) {
+            lookupCache.clear();
+        }
+    }
+
     // TODO don't ignore context
     @Override
     public Tristate getPermissionValue(@NonNull Set<Context> contexts, @NonNull String permission) {
@@ -57,7 +67,18 @@ public class LuckPermsUserSubject extends LuckPermsSubject {
         }
 
         permission = permission.toLowerCase();
+        synchronized (lookupCache) {
+            if (lookupCache.containsKey(permission)) {
+                return lookupCache.get(permission);
+            } else {
+                Tristate t = lookupPermissionValue(contexts, permission);
+                lookupCache.put(permission, t);
+                return t;
+            }
+        }
+    }
 
+    private Tristate lookupPermissionValue(Set<Context> contexts, String permission) {
         if (permissionCache.containsKey(permission)) {
             return Tristate.fromBoolean(permissionCache.get(permission));
         }

sponge/src/main/java/me/lucko/luckperms/users/SpongeUser.java

@@ -25,6 +25,7 @@ package me.lucko.luckperms.users;
 import me.lucko.luckperms.LPSpongePlugin;
 import me.lucko.luckperms.api.event.events.UserPermissionRefreshEvent;
 import me.lucko.luckperms.api.implementation.internal.UserLink;
+import me.lucko.luckperms.api.sponge.LuckPermsUserSubject;
 import me.lucko.luckperms.api.sponge.collections.UserCollection;
 
 import java.util.Collections;
@@ -62,7 +63,8 @@ class SpongeUser extends User {
         );
 
         try {
-            Map<String, Boolean> existing = uc.getUsers().get(getUuid()).getPermissionCache();
+            LuckPermsUserSubject us = uc.getUsers().get(getUuid());
+            Map<String, Boolean> existing = us.getPermissionCache();
 
             boolean different = false;
             if (toApply.size() != existing.size()) {
@@ -80,6 +82,7 @@ class SpongeUser extends User {
             if (!different) return;
 
             existing.clear();
+            us.invalidateCache();
             existing.putAll(toApply);
 
             plugin.getApiProvider().fireEventAsync(new UserPermissionRefreshEvent(new UserLink(this)));