24w09a - Transfer API (FabricMC#3626)

* First pass on transfer API

* More fixes

* Another fix

* Small fixes

* Move transfer API tests to junit

* Fix client run

* Small fixes

* Copy stack when component changes

* Small improvement

* More tests and docs fixes

* Mutate existing stack

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/fluid/FluidStorage.java

@@ -18,13 +18,14 @@
 
 import org.jetbrains.annotations.Nullable;
 
+import net.minecraft.component.DataComponentTypes;
+import net.minecraft.component.type.PotionContentsComponent;
 import net.minecraft.fluid.Fluid;
 import net.minecraft.fluid.Fluids;
 import net.minecraft.item.BucketItem;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.item.Items;
-import net.minecraft.potion.PotionUtil;
 import net.minecraft.potion.Potions;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.math.Direction;
@@ -161,8 +162,8 @@ private FluidStorage() {
 		combinedItemApiProvider(Items.GLASS_BOTTLE).register(context -> {
 			return new EmptyItemFluidStorage(context, emptyBottle -> {
 				ItemStack newStack = emptyBottle.toStack();
-				PotionUtil.setPotion(newStack, Potions.WATER);
-				return ItemVariant.of(Items.POTION, newStack.getNbt());
+				newStack.set(DataComponentTypes.POTION_CONTENTS, new PotionContentsComponent(Potions.WATER));
+				return ItemVariant.of(Items.POTION, newStack.getComponentChanges());
 			}, Fluids.WATER, FluidConstants.BOTTLE);
 		});
 		// Register water potion storage

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/fluid/FluidVariant.java

@@ -16,29 +16,35 @@
 
 package net.fabricmc.fabric.api.transfer.v1.fluid;
 
+import com.mojang.serialization.Codec;
 import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.Nullable;
 
+import net.minecraft.component.ComponentChanges;
 import net.minecraft.fluid.Fluid;
 import net.minecraft.fluid.Fluids;
-import net.minecraft.nbt.NbtCompound;
-import net.minecraft.network.PacketByteBuf;
+import net.minecraft.network.RegistryByteBuf;
+import net.minecraft.network.codec.PacketCodec;
+import net.minecraft.registry.entry.RegistryEntry;
 
 import net.fabricmc.fabric.api.transfer.v1.storage.TransferVariant;
+import net.fabricmc.fabric.impl.transfer.VariantCodecs;
 import net.fabricmc.fabric.impl.transfer.fluid.FluidVariantImpl;
 
 /**
- * An immutable association of a still fluid and an optional NBT tag.
+ * An immutable association of a still fluid and data components.
  *
- * <p>Do not extend this class. Use {@link #of(Fluid)} and {@link #of(Fluid, NbtCompound)} to create instances.
+ * <p>Do not extend this class. Use {@link #of(Fluid)} and {@link #of(Fluid, ComponentChanges)} to create instances.
  *
  * <p>{@link net.fabricmc.fabric.api.transfer.v1.client.fluid.FluidVariantRendering} can be used for client-side rendering of fluid variants.
  *
  * <p><b>Fluid variants must always be compared with {@code equals}, never by reference!</b>
- * {@code hashCode} is guaranteed to be correct and constant time independently of the size of the NBT.
+ * {@code hashCode} is guaranteed to be correct and constant time independently of the size of the components.
  */
 @ApiStatus.NonExtendable
 public interface FluidVariant extends TransferVariant<Fluid> {
+	Codec<FluidVariant> CODEC = VariantCodecs.FLUID_CODEC;
+	PacketCodec<RegistryByteBuf, FluidVariant> PACKET_CODEC = VariantCodecs.FLUID_PACKET_CODEC;
+
 	/**
 	 * Retrieve a blank FluidVariant.
 	 */
@@ -54,18 +60,18 @@ static FluidVariant blank() {
 	 * {@code FluidVariant.of(Fluids.FLOWING_WATER).getFluid() == Fluids.WATER}.
 	 */
 	static FluidVariant of(Fluid fluid) {
-		return of(fluid, null);
+		return of(fluid, ComponentChanges.EMPTY);
 	}
 
 	/**
 	 * Retrieve a FluidVariant with a fluid, and an optional tag.
 	 *
 	 * <p>The flowing and still variations of {@linkplain net.minecraft.fluid.FlowableFluid flowable fluids}
 	 * are normalized to always refer to the still fluid. For example,
-	 * {@code FluidVariant.of(Fluids.FLOWING_WATER, nbt).getFluid() == Fluids.WATER}.
+	 * {@code FluidVariant.of(Fluids.FLOWING_WATER, ComponentChanges.EMPTY).getFluid() == Fluids.WATER}.
 	 */
-	static FluidVariant of(Fluid fluid, @Nullable NbtCompound nbt) {
-		return FluidVariantImpl.of(fluid, nbt);
+	static FluidVariant of(Fluid fluid, ComponentChanges components) {
+		return FluidVariantImpl.of(fluid, components);
 	}
 
 	/**
@@ -75,19 +81,7 @@ default Fluid getFluid() {
 		return getObject();
 	}
 
-	/**
-	 * Deserialize a variant from an NBT compound tag, assuming it was serialized using {@link #toNbt}.
-	 *
-	 * <p>If an error occurs during deserialization, it will be logged with the DEBUG level, and a blank variant will be returned.
-	 */
-	static FluidVariant fromNbt(NbtCompound nbt) {
-		return FluidVariantImpl.fromNbt(nbt);
-	}
-
-	/**
-	 * Read a variant from a packet byte buffer, assuming it was serialized using {@link #toPacket}.
-	 */
-	static FluidVariant fromPacket(PacketByteBuf buf) {
-		return FluidVariantImpl.fromPacket(buf);
+	default RegistryEntry<Fluid> getRegistryEntry() {
+		return getFluid().getRegistryEntry();
 	}
 }

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/fluid/base/EmptyItemFluidStorage.java

@@ -71,7 +71,7 @@ public final class EmptyItemFluidStorage implements InsertionOnlyStorage<FluidVa
 	 * @param insertableAmount The amount of fluid that can be inserted.
 	 */
 	public EmptyItemFluidStorage(ContainerItemContext context, Item fullItem, Fluid insertableFluid, long insertableAmount) {
-		this(context, emptyVariant -> ItemVariant.of(fullItem, emptyVariant.getNbt()), insertableFluid, insertableAmount);
+		this(context, emptyVariant -> ItemVariant.of(fullItem, emptyVariant.getComponents()), insertableFluid, insertableAmount);
 	}
 
 	/**

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/fluid/base/FullItemFluidStorage.java

@@ -52,7 +52,7 @@ public final class FullItemFluidStorage implements ExtractionOnlyStorage<FluidVa
 	 * @param containedAmount How much of {@code containedFluid} is contained.
 	 */
 	public FullItemFluidStorage(ContainerItemContext context, Item emptyItem, FluidVariant containedFluid, long containedAmount) {
-		this(context, fullVariant -> ItemVariant.of(emptyItem, fullVariant.getNbt()), containedFluid, containedAmount);
+		this(context, fullVariant -> ItemVariant.of(emptyItem, fullVariant.getComponents()), containedFluid, containedAmount);
 	}
 
 	/**

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/fluid/base/SingleFluidStorage.java

@@ -19,6 +19,7 @@
 import java.util.Objects;
 
 import net.minecraft.nbt.NbtCompound;
+import net.minecraft.registry.RegistryWrapper;
 
 import net.fabricmc.fabric.api.transfer.v1.fluid.FluidVariant;
 import net.fabricmc.fabric.api.transfer.v1.storage.StoragePreconditions;
@@ -66,8 +67,14 @@ protected final FluidVariant getBlankVariant() {
 	 * Simple implementation of reading from NBT, to match what is written by {@link #writeNbt}.
 	 * Other formats are allowed, this is just a suggestion.
 	 */
-	public void readNbt(NbtCompound nbt) {
-		variant = FluidVariant.fromNbt(nbt.getCompound("variant"));
-		amount = nbt.getLong("amount");
+	public void readNbt(NbtCompound nbt, RegistryWrapper.WrapperLookup wrapperLookup) {
+		SingleVariantStorage.readNbt(this, FluidVariant.CODEC, FluidVariant::blank, nbt, wrapperLookup);
+	}
+
+	/**
+	 * Simple implementation of writing to NBT. Other formats are allowed, this is just a convenient suggestion.
+	 */
+	public void writeNbt(NbtCompound nbt, RegistryWrapper.WrapperLookup wrapperLookup) {
+		SingleVariantStorage.writeNbt(this, FluidVariant.CODEC, nbt, wrapperLookup);
 	}
 }

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/item/ItemVariant.java

@@ -16,26 +16,34 @@
 
 package net.fabricmc.fabric.api.transfer.v1.item;
 
+import java.util.Objects;
+
+import com.mojang.serialization.Codec;
 import org.jetbrains.annotations.ApiStatus;
-import org.jetbrains.annotations.Nullable;
 
+import net.minecraft.component.ComponentChanges;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemConvertible;
 import net.minecraft.item.ItemStack;
 import net.minecraft.item.Items;
-import net.minecraft.nbt.NbtCompound;
-import net.minecraft.network.PacketByteBuf;
+import net.minecraft.network.RegistryByteBuf;
+import net.minecraft.network.codec.PacketCodec;
+import net.minecraft.registry.entry.RegistryEntry;
 
 import net.fabricmc.fabric.api.transfer.v1.storage.TransferVariant;
+import net.fabricmc.fabric.impl.transfer.VariantCodecs;
 import net.fabricmc.fabric.impl.transfer.item.ItemVariantImpl;
 
 /**
- * An immutable count-less ItemStack, i.e. an immutable association of an item and an optional NBT compound tag.
+ * An immutable count-less ItemStack, i.e. an immutable association of an item and its data components.
  *
  * <p>Do not implement, use the static {@code of(...)} functions instead.
  */
 @ApiStatus.NonExtendable
 public interface ItemVariant extends TransferVariant<Item> {
+	Codec<ItemVariant> CODEC = VariantCodecs.ITEM_CODEC;
+	PacketCodec<RegistryByteBuf, ItemVariant> PACKET_CODEC = VariantCodecs.ITEM_PACKET_CODEC;
+
 	/**
 	 * Retrieve a blank ItemVariant.
 	 */
@@ -47,28 +55,28 @@ static ItemVariant blank() {
 	 * Retrieve an ItemVariant with the item and tag of a stack.
 	 */
 	static ItemVariant of(ItemStack stack) {
-		return of(stack.getItem(), stack.getNbt());
+		return of(stack.getItem(), stack.getComponentChanges());
 	}
 
 	/**
 	 * Retrieve an ItemVariant with an item and without a tag.
 	 */
 	static ItemVariant of(ItemConvertible item) {
-		return of(item, null);
+		return of(item, ComponentChanges.EMPTY);
 	}
 
 	/**
 	 * Retrieve an ItemVariant with an item and an optional tag.
 	 */
-	static ItemVariant of(ItemConvertible item, @Nullable NbtCompound tag) {
-		return ItemVariantImpl.of(item.asItem(), tag);
+	static ItemVariant of(ItemConvertible item, ComponentChanges components) {
+		return ItemVariantImpl.of(item.asItem(), components);
 	}
 
 	/**
 	 * Return true if the item and tag of this variant match those of the passed stack, and false otherwise.
 	 */
 	default boolean matches(ItemStack stack) {
-		return isOf(stack.getItem()) && nbtMatches(stack.getNbt());
+		return isOf(stack.getItem()) && Objects.equals(stack.getComponentChanges(), getComponents());
 	}
 
 	/**
@@ -78,6 +86,10 @@ default Item getItem() {
 		return getObject();
 	}
 
+	default RegistryEntry<Item> getRegistryEntry() {
+		return getItem().getRegistryEntry();
+	}
+
 	/**
 	 * Create a new item stack with count 1 from this variant.
 	 */
@@ -92,25 +104,6 @@ default ItemStack toStack() {
 	 */
 	default ItemStack toStack(int count) {
 		if (isBlank()) return ItemStack.EMPTY;
-		ItemStack stack = new ItemStack(getItem(), count);
-		stack.setNbt(copyNbt());
-		return stack;
-	}
-
-	/**
-	 * Deserialize a variant from an NBT compound tag, assuming it was serialized using
-	 * {@link #toNbt}. If an error occurs during deserialization, it will be logged
-	 * with the DEBUG level, and a blank variant will be returned.
-	 */
-	static ItemVariant fromNbt(NbtCompound nbt) {
-		return ItemVariantImpl.fromNbt(nbt);
-	}
-
-	/**
-	 * Write a variant from a packet byte buffer, assuming it was serialized using
-	 * {@link #toPacket}.
-	 */
-	static ItemVariant fromPacket(PacketByteBuf buf) {
-		return ItemVariantImpl.fromPacket(buf);
+		return new ItemStack(getRegistryEntry(), count, getComponents());
 	}
 }

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/item/base/SingleItemStorage.java

@@ -17,6 +17,7 @@
 package net.fabricmc.fabric.api.transfer.v1.item.base;
 
 import net.minecraft.nbt.NbtCompound;
+import net.minecraft.registry.RegistryWrapper;
 
 import net.fabricmc.fabric.api.transfer.v1.item.ItemVariant;
 import net.fabricmc.fabric.api.transfer.v1.storage.TransferVariant;
@@ -40,8 +41,14 @@ protected final ItemVariant getBlankVariant() {
 	 * Simple implementation of reading from NBT, to match what is written by {@link #writeNbt}.
 	 * Other formats are allowed, this is just a suggestion.
 	 */
-	public void readNbt(NbtCompound nbt) {
-		variant = ItemVariant.fromNbt(nbt.getCompound("variant"));
-		amount = nbt.getLong("amount");
+	public void readNbt(NbtCompound nbt, RegistryWrapper.WrapperLookup wrapperLookup) {
+		SingleVariantStorage.readNbt(this, ItemVariant.CODEC, ItemVariant::blank, nbt, wrapperLookup);
+	}
+
+	/**
+	 * Simple implementation of writing to NBT. Other formats are allowed, this is just a convenient suggestion.
+	 */
+	public void writeNbt(NbtCompound nbt, RegistryWrapper.WrapperLookup wrapperLookup) {
+		SingleVariantStorage.writeNbt(this, ItemVariant.CODEC, nbt, wrapperLookup);
 	}
 }

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/api/transfer/v1/storage/TransferVariant.java

@@ -18,13 +18,10 @@
 
 import java.util.Objects;
 
-import org.jetbrains.annotations.Nullable;
-
-import net.minecraft.nbt.NbtCompound;
-import net.minecraft.network.PacketByteBuf;
+import net.minecraft.component.ComponentChanges;
 
 /**
- * An immutable association of an immutable object instance (for example {@code Item} or {@code Fluid}) and an optional NBT tag.
+ * An immutable association of an immutable object instance (for example {@code Item} or {@code Fluid}) and data components.
  *
  * <p>This is exposed for convenience for code that needs to be generic across multiple transfer variants,
  * but note that a {@link Storage} is not necessarily bound to {@code TransferVariant}. Its generic parameter can be any immutable object.
@@ -46,27 +43,24 @@ public interface TransferVariant<O> {
 	O getObject();
 
 	/**
-	 * Return the underlying tag.
-	 *
-	 * <p><b>NEVER MUTATE THIS NBT TAG</b>, if you need to mutate it you can use {@link #copyNbt()} to retrieve a copy instead.
+	 * @return The {@link ComponentChanges} of this variant.
 	 */
-	@Nullable
-	NbtCompound getNbt();
+	ComponentChanges getComponents();
 
 	/**
-	 * Return true if this variant has a tag, false otherwise.
+	 * Return true if this variant has a component changes.
 	 */
-	default boolean hasNbt() {
-		return getNbt() != null;
+	default boolean hasComponents() {
+		return !getComponents().isEmpty();
 	}
 
 	/**
 	 * Return true if the tag of this variant matches the passed tag, and false otherwise.
 	 *
 	 * <p>Note: True is returned if both tags are {@code null}.
 	 */
-	default boolean nbtMatches(@Nullable NbtCompound other) {
-		return Objects.equals(getNbt(), other);
+	default boolean componentsMatches(ComponentChanges other) {
+		return Objects.equals(getComponents(), other);
 	}
 
 	/**
@@ -75,37 +69,4 @@ default boolean nbtMatches(@Nullable NbtCompound other) {
 	default boolean isOf(O object) {
 		return getObject() == object;
 	}
-
-	/**
-	 * Return a copy of the tag of this variant, or {@code null} if this variant doesn't have a tag.
-	 *
-	 * <p>Note: Use {@link #nbtMatches} if you only need to check for custom tag equality, or {@link #getNbt()} if you don't need to mutate the tag.
-	 */
-	@Nullable
-	default NbtCompound copyNbt() {
-		NbtCompound nbt = getNbt();
-		return nbt == null ? null : nbt.copy();
-	}
-
-	/**
-	 * Return a copy of the tag of this variant, or a new compound if this variant doesn't have a tag.
-	 */
-	default NbtCompound copyOrCreateNbt() {
-		NbtCompound nbt = getNbt();
-		return nbt == null ? new NbtCompound() : nbt.copy();
-	}
-
-	/**
-	 * Save this variant into an NBT compound tag. Subinterfaces should have a matching static {@code fromNbt}.
-	 *
-	 * <p>Note: This is safe to use for persisting data as objects are saved using their full Identifier.
-	 */
-	NbtCompound toNbt();
-
-	/**
-	 * Write this variant into a packet byte buffer. Subinterfaces should have a matching static {@code fromPacket}.
-	 *
-	 * <p>Implementation note: Objects are saved using their raw registry integer id.
-	 */
-	void toPacket(PacketByteBuf buf);
 }