Add ItemStack#copyDataFrom (#12224)

Author: TonytheMacaroni

paper-api/src/main/java/io/papermc/paper/registry/RegistryKey.java

@@ -79,7 +79,7 @@ public sealed interface RegistryKey<T> extends Keyed permits RegistryKeyImpl {
     RegistryKey<BlockType> BLOCK = create("block");
     /**
      * @apiNote use preferably only in the context of registry entries.
-     * @see io.papermc.paper.registry.data
+     * @see io.papermc.paper.registry.keys.ItemTypeKeys
      */
     @ApiStatus.Experimental // Paper - already required for registry builders
     RegistryKey<ItemType> ITEM = create("item");

paper-api/src/main/java/org/bukkit/inventory/ItemStack.java

@@ -6,6 +6,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.function.Consumer;
+import java.util.function.Predicate;
 import net.kyori.adventure.text.Component;
 import org.bukkit.Bukkit;
 import org.bukkit.Material;
@@ -1306,6 +1307,31 @@ public void resetData(final io.papermc.paper.datacomponent.@NotNull DataComponen
         this.craftDelegate.resetData(type);
     }
 
+    /**
+     * Copies component values and component removals from the provided ItemStack.
+     * <p>
+     * Example:
+     * <pre>{@code
+     * Set<DataComponentType> types = Set.of(
+     *     DataComponentTypes.CONSUMABLE,
+     *     DataComponentTypes.ENCHANTMENT_GLINT_OVERRIDE,
+     *     DataComponentTypes.RARITY
+     * );
+     *
+     * ItemStack source = ItemStack.of(Material.ENCHANTED_GOLDEN_APPLE);
+     * ItemStack target = ItemStack.of(Material.GOLDEN_CARROT);
+     *
+     * target.copyDataFrom(source, types::contains);
+     * }</pre>
+     *
+     * @param source the item stack to copy from
+     * @param filter predicate for which components to copy
+     */
+    @org.jetbrains.annotations.ApiStatus.Experimental
+    public void copyDataFrom(final @NotNull ItemStack source, final @NotNull Predicate<io.papermc.paper.datacomponent.@NotNull DataComponentType> filter) {
+        this.craftDelegate.copyDataFrom(source, filter);
+    }
+
     /**
      * Checks if the data component type is overridden from the default for the
      * item type.

paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java

@@ -7,6 +7,7 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.Consumer;
+import java.util.function.Predicate;
 import net.kyori.adventure.text.Component;
 import net.minecraft.advancements.critereon.ItemPredicate;
 import net.minecraft.advancements.critereon.MinMaxBounds;
@@ -15,6 +16,7 @@
 import net.minecraft.core.component.DataComponentMap;
 import net.minecraft.core.component.DataComponentPatch;
 import net.minecraft.core.component.DataComponentPredicate;
+import net.minecraft.core.component.DataComponentType;
 import net.minecraft.core.component.DataComponents;
 import net.minecraft.core.component.PatchedDataComponentMap;
 import net.minecraft.nbt.CompoundTag;
@@ -54,7 +56,7 @@ private static CraftItemStack getCraftStack(final ItemStack bukkit) {
         if (bukkit instanceof final CraftItemStack craftItemStack) {
             return craftItemStack;
         } else {
-            return  (CraftItemStack) API_ITEM_STACK_CRAFT_DELEGATE_FIELD.get(bukkit);
+            return (CraftItemStack) API_ITEM_STACK_CRAFT_DELEGATE_FIELD.get(bukkit);
         }
     }
 
@@ -71,12 +73,12 @@ public int hashCode() {
 
     @Override
     public boolean equals(final Object obj) {
-        if (!(obj instanceof final org.bukkit.inventory.ItemStack bukkit)) return false;
+        if (!(obj instanceof final ItemStack bukkit)) return false;
         final CraftItemStack craftStack = getCraftStack(bukkit);
         if (this.handle == craftStack.handle) return true;
-        else if (this.handle == null || craftStack.handle == null) return false;
-        else if (this.handle.isEmpty() && craftStack.handle.isEmpty()) return true;
-        else return net.minecraft.world.item.ItemStack.matches(this.handle, craftStack.handle);
+        if (this.handle == null || craftStack.handle == null) return false;
+        if (this.handle.isEmpty() && craftStack.handle.isEmpty()) return true;
+        return net.minecraft.world.item.ItemStack.matches(this.handle, craftStack.handle);
     }
     // Paper end
 
@@ -648,14 +650,32 @@ private <M> void resetData(final io.papermc.paper.datacomponent.PaperDataCompone
         this.handle.set(nms, nmsValue);
     }
 
+    @Override
+    public void copyDataFrom(final ItemStack source, final Predicate<io.papermc.paper.datacomponent.DataComponentType> filter) {
+        Preconditions.checkArgument(source != null, "source cannot be null");
+        Preconditions.checkArgument(filter != null, "filter cannot be null");
+        if (this.isEmpty() || source.isEmpty()) {
+            return;
+        }
+
+        final Predicate<DataComponentType<?>> nmsFilter = nms -> filter.test(io.papermc.paper.datacomponent.PaperDataComponentType.minecraftToBukkit(nms));
+        net.minecraft.world.item.ItemStack sourceNmsStack = getCraftStack(source).handle;
+        this.handle.applyComponents(sourceNmsStack.getPrototype().filter(nmsType -> {
+            return !sourceNmsStack.hasNonDefault(nmsType) && nmsFilter.test(nmsType);
+        }));
+
+        final DataComponentPatch.SplitResult split = sourceNmsStack.getComponentsPatch().split();
+        this.handle.applyComponents(split.added().filter(nmsFilter));
+        split.removed().stream().filter(nmsFilter).forEach(this.handle::remove);
+    }
+
     @Override
     public boolean isDataOverridden(final io.papermc.paper.datacomponent.DataComponentType type) {
         if (this.isEmpty()) {
             return false;
         }
         final net.minecraft.core.component.DataComponentType<?> nms = io.papermc.paper.datacomponent.PaperDataComponentType.bukkitToMinecraft(type);
-        // maybe a more efficient way is to expose the "patch" map in PatchedDataComponentMap and just check if the type exists as a key
-        return !java.util.Objects.equals(this.handle.get(nms), this.handle.getPrototype().get(nms));
+        return this.handle.hasNonDefault(nms);
     }
 
     @Override