Improve AESharedItemStack caching

Reduces the item stack churn a little, improving overall server time taken from 6% to 2% on average

src/main/java/appeng/util/item/AEItemStackRegistry.java

@@ -23,14 +23,16 @@
 
 package appeng.util.item;
 
+import com.google.common.collect.MapMaker;
 import net.minecraft.item.ItemStack;
 
 import javax.annotation.Nonnull;
-import java.lang.ref.WeakReference;
-import java.util.WeakHashMap;
+import java.util.Map;
 
 public final class AEItemStackRegistry {
- private static final WeakHashMap<AESharedItemStack, WeakReference<AESharedItemStack>> REGISTRY = new WeakHashMap<>();
+
+ private static final ItemStackHashStrategy HASH_STRATEGY = ItemStackHashStrategy.comparingAllButCount();
+ private static final Map<Integer, AESharedItemStack> REGISTRY = new MapMaker().weakValues().makeMap();
 
  private AEItemStackRegistry() {
  }
@@ -40,23 +42,18 @@ static synchronized AESharedItemStack getRegisteredStack(final @Nonnull ItemStac
  throw new IllegalArgumentException("stack cannot be empty");
  }
 
- int oldStackSize = itemStack.getCount();
- itemStack.setCount(1);
-
- AESharedItemStack search = new AESharedItemStack(itemStack);
- WeakReference<AESharedItemStack> weak = REGISTRY.get(search);
- AESharedItemStack ret = null;
-
- if (weak != null) {
- ret = weak.get();
- }
-
- if (ret == null) {
- ret = new AESharedItemStack(itemStack.copy());
- REGISTRY.put(ret, new WeakReference<>(ret));
+ var hash = HASH_STRATEGY.hashCode(itemStack);
+ var ret = REGISTRY.get(hash);
+ if (ret != null) {
+ return ret;
  }
- itemStack.setCount(oldStackSize);
 
- return ret;
+ // computeIfAbsent is not feasible since new AESharedItemStack gets
+ // instantly GC'd when leaving the lambda.
+ var itemStackCopy = itemStack.copy();
+ itemStackCopy.setCount(1);
+ var sharedStack = new AESharedItemStack(itemStackCopy);
+ REGISTRY.put(hash, sharedStack);
+ return sharedStack;
  }
 }