minecraft-src/net/minecraft/resources/RegistryOps.java

package net.minecraft.resources;

import com.mojang.serialization.DataResult;
import com.mojang.serialization.Dynamic;
import com.mojang.serialization.DynamicOps;
import com.mojang.serialization.Lifecycle;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import net.minecraft.core.Holder;
import net.minecraft.core.HolderGetter;
import net.minecraft.core.HolderLookup;
import net.minecraft.core.HolderOwner;
import net.minecraft.core.Registry;
import net.minecraft.util.ExtraCodecs;

public class RegistryOps<T> extends DelegatingOps<T> {
	private final RegistryOps.RegistryInfoLookup lookupProvider;

	public static <T> RegistryOps<T> create(DynamicOps<T> delegate, HolderLookup.Provider registries) {
		return create(delegate, new RegistryOps.HolderLookupAdapter(registries));
	}

	public static <T> RegistryOps<T> create(DynamicOps<T> delegate, RegistryOps.RegistryInfoLookup lookupProvider) {
		return new RegistryOps<>(delegate, lookupProvider);
	}

	public static <T> Dynamic<T> injectRegistryContext(Dynamic<T> dynamic, HolderLookup.Provider registries) {
		return new Dynamic<>(registries.createSerializationContext(dynamic.getOps()), dynamic.getValue());
	}

	private RegistryOps(DynamicOps<T> delegate, RegistryOps.RegistryInfoLookup lookupProvider) {
		super(delegate);
		this.lookupProvider = lookupProvider;
	}

	public <U> RegistryOps<U> withParent(DynamicOps<U> ops) {
		return (RegistryOps<U>)(ops == this.delegate ? this : new RegistryOps<>(ops, this.lookupProvider));
	}

	public <E> Optional<HolderOwner<E>> owner(ResourceKey<? extends Registry<? extends E>> registryKey) {
		return this.lookupProvider.lookup(registryKey).map(RegistryOps.RegistryInfo::owner);
	}

	public <E> Optional<HolderGetter<E>> getter(ResourceKey<? extends Registry<? extends E>> registryKey) {
		return this.lookupProvider.lookup(registryKey).map(RegistryOps.RegistryInfo::getter);
	}

	public boolean equals(Object object) {
		if (this == object) {
			return true;
		} else if (object != null && this.getClass() == object.getClass()) {
			RegistryOps<?> registryOps = (RegistryOps<?>)object;
			return this.delegate.equals(registryOps.delegate) && this.lookupProvider.equals(registryOps.lookupProvider);
		} else {
			return false;
		}
	}

	public int hashCode() {
		return this.delegate.hashCode() * 31 + this.lookupProvider.hashCode();
	}

	public static <E, O> RecordCodecBuilder<O, HolderGetter<E>> retrieveGetter(ResourceKey<? extends Registry<? extends E>> registryOps) {
		return ExtraCodecs.<HolderGetter<E>>retrieveContext(
				dynamicOps -> dynamicOps instanceof RegistryOps<?> registryOpsx
					? (DataResult)registryOpsx.lookupProvider
						.lookup(registryOps)
						.map(registryInfo -> DataResult.success(registryInfo.getter(), registryInfo.elementsLifecycle()))
						.orElseGet(() -> DataResult.error(() -> "Unknown registry: " + registryOps))
					: DataResult.error(() -> "Not a registry ops")
			)
			.forGetter(object -> null);
	}

	public static <E, O> RecordCodecBuilder<O, Holder.Reference<E>> retrieveElement(ResourceKey<E> key) {
		ResourceKey<? extends Registry<E>> resourceKey = ResourceKey.createRegistryKey(key.registry());
		return ExtraCodecs.<Holder.Reference<E>>retrieveContext(
				dynamicOps -> dynamicOps instanceof RegistryOps<?> registryOps
					? (DataResult)registryOps.lookupProvider
						.lookup(resourceKey)
						.flatMap(registryInfo -> registryInfo.getter().get(key))
						.map(DataResult::success)
						.orElseGet(() -> DataResult.error(() -> "Can't find value: " + key))
					: DataResult.error(() -> "Not a registry ops")
			)
			.forGetter(object -> null);
	}

	static final class HolderLookupAdapter implements RegistryOps.RegistryInfoLookup {
		private final HolderLookup.Provider lookupProvider;
		private final Map<ResourceKey<? extends Registry<?>>, Optional<? extends RegistryOps.RegistryInfo<?>>> lookups = new ConcurrentHashMap();

		public HolderLookupAdapter(HolderLookup.Provider lookupProvider) {
			this.lookupProvider = lookupProvider;
		}

		@Override
		public <E> Optional<RegistryOps.RegistryInfo<E>> lookup(ResourceKey<? extends Registry<? extends E>> registryKey) {
			return (Optional<RegistryOps.RegistryInfo<E>>)this.lookups.computeIfAbsent(registryKey, this::createLookup);
		}

		private Optional<RegistryOps.RegistryInfo<Object>> createLookup(ResourceKey<? extends Registry<?>> registryKey) {
			return this.lookupProvider.lookup(registryKey).map(RegistryOps.RegistryInfo::fromRegistryLookup);
		}

		public boolean equals(Object object) {
			return this == object
				? true
				: object instanceof RegistryOps.HolderLookupAdapter holderLookupAdapter && this.lookupProvider.equals(holderLookupAdapter.lookupProvider);
		}

		public int hashCode() {
			return this.lookupProvider.hashCode();
		}
	}

	public record RegistryInfo<T>(HolderOwner<T> owner, HolderGetter<T> getter, Lifecycle elementsLifecycle) {
		public static <T> RegistryOps.RegistryInfo<T> fromRegistryLookup(HolderLookup.RegistryLookup<T> registryLookup) {
			return new RegistryOps.RegistryInfo<>(registryLookup, registryLookup, registryLookup.registryLifecycle());
		}
	}

	public interface RegistryInfoLookup {
		<T> Optional<RegistryOps.RegistryInfo<T>> lookup(ResourceKey<? extends Registry<? extends T>> registryKey);
	}
}