ItemContainerContents.java.patch

--- a/net/minecraft/world/item/component/ItemContainerContents.java
+++ b/net/minecraft/world/item/component/ItemContainerContents.java
@@ -146,6 +_,38 @@
         return this.hashCode;
     }
 
+    // Neo Start
+
+    /**
+     * {@return the number of slots in this container}
+     */
+    public int getSlots() {
+        return this.items.size();
+    }
+
+    /**
+     * Gets a copy of the stack at a particular slot.
+     *
+     * @param slot The slot to check. Must be within [0, {@link #getSlots()}]
+     * @return A copy of the stack in that slot
+     * @throws UnsupportedOperationException if the provided slot index is out-of-bounds.
+     */
+    public ItemStack getStackInSlot(int slot) {
+        validateSlotIndex(slot);
+        return this.items.get(slot).copy();
+    }
+
+    /**
+     * Throws {@link UnsupportedOperationException} if the provided slot index is invalid.
+     */
+    private void validateSlotIndex(int slot) {
+        if (slot < 0 || slot >= getSlots()) {
+            throw new UnsupportedOperationException("Slot " + slot + " not in valid range - [0," + getSlots() + ")");
+        }
+    }
+
+    // Neo End
+
     static record Slot(int index, ItemStack item) {
         public static final Codec<ItemContainerContents.Slot> CODEC = RecordCodecBuilder.create(
             p_331695_ -> p_331695_.group(