magento2/app/code/Magento/ConfigurableProduct/Model/AttributeOptionProvider.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

namespace Magento\ConfigurableProduct\Model;

use Magento\ConfigurableProduct\Model\ResourceModel\Attribute\OptionSelectBuilderInterface;
use Magento\Eav\Model\Entity\Attribute\AbstractAttribute;
use Magento\Framework\App\ScopeResolverInterface;
use Magento\ConfigurableProduct\Model\ResourceModel\Product\Type\Configurable\Attribute;
use Magento\Framework\DB\Select;

/**
 * Provider for retrieving configurable options.
 */
class AttributeOptionProvider implements AttributeOptionProviderInterface
{
    /**
     * @var ScopeResolverInterface
     */
    private $scopeResolver;

    /**
     * @var Attribute
     */
    private $attributeResource;

    /**
     * @var OptionSelectBuilderInterface
     */
    private $optionSelectBuilder;

    /**
     * @param Attribute $attributeResource
     * @param ScopeResolverInterface $scopeResolver,
     * @param OptionSelectBuilderInterface $optionSelectBuilder
     */
    public function __construct(
        Attribute $attributeResource,
        ScopeResolverInterface $scopeResolver,
        OptionSelectBuilderInterface $optionSelectBuilder
    ) {
        $this->attributeResource = $attributeResource;
        $this->scopeResolver = $scopeResolver;
        $this->optionSelectBuilder = $optionSelectBuilder;
    }

    /**
     * {@inheritdoc}
     */
    public function getAttributeOptions(AbstractAttribute $superAttribute, $productId)
    {
        $scope  = $this->scopeResolver->getScope();
        $select = $this->optionSelectBuilder->getSelect($superAttribute, $productId, $scope);
        $data = $this->attributeResource->getConnection()->fetchAll($select);

        if ($superAttribute->getSourceModel()) {
            $options = $superAttribute->getSource()->getAllOptions(false);

            $optionLabels = [];
            foreach ($options as $option) {
                $optionLabels[$option['value']] = $option['label'];
            }

            foreach ($data as $key => $value) {
                $optionText = isset($optionLabels[$value['value_index']])
                    ? $optionLabels[$value['value_index']]
                    : false;
                $data[$key]['default_title'] = $optionText;
                $data[$key]['option_title'] = $optionText;
            }
        }

        return $data;
    }
}