LeavesMC/patches/server/0101-Avoid-Class-isAssignableFrom-call-in-ClassInstanceMu.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: violetc <58360096+s-yh-china@users.noreply.github.com>
Date: Thu, 20 Jul 2023 17:23:33 +0800
Subject: [PATCH] Avoid Class#isAssignableFrom call in ClassInstanceMultiMap

This patch is Powered by Gale(https://github.com/GaleMC/Gale)

diff --git a/src/main/java/net/minecraft/util/ClassInstanceMultiMap.java b/src/main/java/net/minecraft/util/ClassInstanceMultiMap.java
index 53021c7d173b3c067322e356fead0949aac3fc60..820343861893a0aba55ede10ac2a2594de4438d0 100644
--- a/src/main/java/net/minecraft/util/ClassInstanceMultiMap.java
+++ b/src/main/java/net/minecraft/util/ClassInstanceMultiMap.java
@@ -55,14 +55,24 @@ public class ClassInstanceMultiMap<T> extends AbstractCollection<T> {
     }
 
     public <S> Collection<S> find(Class<S> type) {
-        if (!this.baseClass.isAssignableFrom(type)) {
-            throw new IllegalArgumentException("Don't know how to search for " + type);
-        } else {
-            List list = this.byClass.computeIfAbsent(type, (typeClass) -> { // Leaves - dev fix
-                return this.allInstances.stream().filter(typeClass::isInstance).collect(Collectors.toList());
-            });
-            return Collections.unmodifiableCollection(list);
+        // Leaves start - avoid Class#isAssignableFrom call in ClassInstanceMultiMap
+        Collection<T> collection = this.byClass.get(type);
+        if (collection == null) {
+            collection = this.createAllOfType(type);
         }
+        return (Collection<S>) Collections.unmodifiableCollection(collection);
+    }
+
+    private <S> Collection<T> createAllOfType(Class<S> type) {
+        List<T> list = new java.util.ArrayList<>(1);
+        for (T allElement : this.allInstances) {
+            if (type.isInstance(allElement)) {
+                list.add(allElement);
+            }
+        }
+        this.byClass.put(type, list);
+        return list;
+        // Leaves end - avoid Class#isAssignableFrom call in ClassInstanceMultiMap
     }
 
     @Override