Cache ItemStacks to improve performance

src/main/java/aztech/modern_industrialization/inventory/ConfigurableItemStack.java

@@ -28,6 +28,7 @@
 import aztech.modern_industrialization.compat.viewer.ReiDraggable;
 import aztech.modern_industrialization.thirdparty.fabrictransfer.api.fluid.FluidVariant;
 import aztech.modern_industrialization.thirdparty.fabrictransfer.api.item.ItemVariant;
+import aztech.modern_industrialization.thirdparty.fabrictransfer.api.storage.base.ResourceAmount;
 import aztech.modern_industrialization.util.Simulation;
 import java.util.ArrayList;
 import java.util.List;
@@ -50,6 +51,8 @@
 public class ConfigurableItemStack extends AbstractConfigurableStack<Item, ItemVariant> implements ItemAccess {
     private int adjustedCapacity = 64;
 
+    private @Nullable ItemStack cachedItemStack;
+
     public ConfigurableItemStack() {}
 
     public ConfigurableItemStack(CompoundTag compound, HolderLookup.Provider registries) {
@@ -191,6 +194,32 @@ public ItemVariant getVariant() {
         return getResource();
     }
 
+    @Override
+    public ItemStack toStack() {
+        if (cachedItemStack == null) {
+            cachedItemStack = ItemAccess.super.toStack();
+        }
+        return cachedItemStack;
+    }
+
+    @Override
+    public void setAmount(long amount) {
+        cachedItemStack = null;
+        super.setAmount(amount);
+    }
+
+    @Override
+    public void setKey(ItemVariant key) {
+        cachedItemStack = null;
+        super.setKey(key);
+    }
+
+    @Override
+    public void revertToSnapshot(ResourceAmount<ItemVariant> ra) {
+        cachedItemStack = null;
+        super.revertToSnapshot(ra);
+    }
+
     public class ConfigurableItemSlot extends HackySlot implements ReiDraggable, BackgroundRenderedSlot {
         private final Predicate<ItemStack> insertPredicate;
         private final Runnable markDirty;
@@ -231,6 +260,7 @@ protected ItemStack getRealStack() {
         protected void setRealStack(ItemStack stack) {
             key = ItemVariant.of(stack);
             amount = stack.getCount();
+            cachedItemStack = null;
             notifyListeners();
             markDirty.run();
         }

src/main/java/aztech/modern_industrialization/inventory/MIItemStorage.java

@@ -26,7 +26,6 @@
 
 import aztech.modern_industrialization.thirdparty.fabrictransfer.api.item.ItemVariant;
 import aztech.modern_industrialization.thirdparty.fabrictransfer.api.transaction.Transaction;
-import com.google.common.primitives.Ints;
 import java.util.List;
 import java.util.Set;
 import net.minecraft.world.item.Item;
@@ -49,7 +48,7 @@ public int getSlots() {
 
         @Override
         public ItemStack getStackInSlot(int slot) {
-            return stacks.get(slot).getVariant().toStack(Ints.saturatedCast(stacks.get(slot).getAmount()));
+            return stacks.get(slot).toStack();
         }
 
         @Override

src/main/java/aztech/modern_industrialization/thirdparty/fabrictransfer/api/bridge/SlotItemHandler.java

@@ -30,16 +30,32 @@
 import com.google.common.primitives.Ints;
 import net.minecraft.world.item.ItemStack;
 import net.neoforged.neoforge.items.IItemHandler;
+import org.jspecify.annotations.Nullable;
+
+public final class SlotItemHandler implements IItemHandler {
+    private final SingleSlotStorage<ItemVariant> storage;
+
+    private @Nullable ItemStack cachedItemStack;
+
+    public SlotItemHandler(SingleSlotStorage<ItemVariant> storage) {
+        this.storage = storage;
+    }
+
+    public SingleSlotStorage<ItemVariant> storage() {
+        return storage;
+    }
 
-public record SlotItemHandler(SingleSlotStorage<ItemVariant> storage) implements IItemHandler {
     @Override
     public int getSlots() {
         return 1;
     }
 
     @Override
     public ItemStack getStackInSlot(int slot) {
-        return storage.getResource().toStack(Ints.saturatedCast(storage.getAmount()));
+        if (cachedItemStack == null) {
+            cachedItemStack = storage.getResource().toStack(Ints.saturatedCast(storage.getAmount()));
+        }
+        return cachedItemStack;
     }
 
     @Override
@@ -51,6 +67,9 @@ public ItemStack insertItem(int slot, ItemStack stack, boolean simulate) {
             var inserted = storage.insert(ItemVariant.of(stack), stack.getCount(), tx);
             if (!simulate) {
                 tx.commit();
+                if (inserted > 0) {
+                    cachedItemStack = null;
+                }
             }
             return inserted == 0 ? stack : stack.copyWithCount(stack.getCount() - (int) inserted);
         }
@@ -69,6 +88,9 @@ public ItemStack extractItem(int slot, int amount, boolean simulate) {
             var extracted = storage.extract(resource, amount, tx);
             if (!simulate) {
                 tx.commit();
+                if (extracted > 0) {
+                    cachedItemStack = null;
+                }
             }
             return extracted == 0 ? ItemStack.EMPTY : resource.toStack((int) extracted);
         }

src/main/java/aztech/modern_industrialization/thirdparty/fabrictransfer/impl/item/ItemVariantImpl.java

@@ -51,7 +51,7 @@ public static ItemVariant of(ItemStack stack) {
         if (stack.isComponentsPatchEmpty() || stack.isEmpty()) {
             return of(stack.getItem());
         } else {
-            return new ItemVariantImpl(stack);
+            return new ItemVariantImpl(stack.copyWithCount(1)); // defensive copy
         }
     }
 
@@ -61,7 +61,7 @@ public static ItemVariant of(ItemStack stack) {
     private final int hashCode;
 
     private ItemVariantImpl(ItemStack stack) {
-        this.stack = stack.copyWithCount(1); // defensive copy
+        this.stack = stack;
         hashCode = ItemStack.hashItemAndComponents(stack);
     }