Code/net/minecraft/world/entity/OwnableEntity.java

package net.minecraft.world.entity;

import it.unimi.dsi.fastutil.objects.ObjectArraySet;
import java.util.Set;
import javax.annotation.Nullable;
import net.minecraft.world.level.Level;

public interface OwnableEntity {
    @Nullable
    EntityReference<LivingEntity> getOwnerReference();

    Level level();

    @Nullable
    default LivingEntity getOwner() {
        return EntityReference.get(this.getOwnerReference(), this.level(), LivingEntity.class);
    }

    @Nullable
    default LivingEntity getRootOwner() {
        Set<Object> set = new ObjectArraySet<>();
        LivingEntity livingentity = this.getOwner();
        set.add(this);

        while (livingentity instanceof OwnableEntity) {
            OwnableEntity ownableentity = (OwnableEntity)livingentity;
            LivingEntity livingentity1 = ownableentity.getOwner();
            if (set.contains(livingentity1)) {
                return null;
            }

            set.add(livingentity);
            livingentity = ownableentity.getOwner();
        }

        return livingentity;
    }
}