WC_Product_Data_Store_CPT::update_downloads PHP Method

    protected function update_downloads(&$product)
    {
        $downloads = $product->get_downloads();
        $meta_values = array();
        if ($downloads) {
            foreach ($downloads as $key => $download) {
                // Store in format WC uses in meta.
                $meta_values[$key] = $download->get_data();
            }
        }
        if ($product->is_type('variation')) {
            do_action('woocommerce_process_product_file_download_paths', $product->get_parent_id(), $product->get_id(), $downloads);
        } else {
            do_action('woocommerce_process_product_file_download_paths', $product->get_id(), 0, $downloads);
        }
        update_post_meta($product->get_id(), '_downloadable_files', $meta_values);
    }