woothemes/woocommerce

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includes/admin/list-tables/class-wc-admin-list-table-products.php

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2 days
Test Coverage
<?php
/**
 * List tables: products.
 *
 * @package  WooCommerce\Admin
 * @version  3.3.0
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

if ( class_exists( 'WC_Admin_List_Table_Products', false ) ) {
    return;
}

if ( ! class_exists( 'WC_Admin_List_Table', false ) ) {
    include_once __DIR__ . '/abstract-class-wc-admin-list-table.php';
}

/**
 * WC_Admin_List_Table_Products Class.
 */
class WC_Admin_List_Table_Products extends WC_Admin_List_Table {

    /**
     * Post type.
     *
     * @var string
     */
    protected $list_table_type = 'product';

    /**
     * Constructor.
     */
    public function __construct() {
        parent::__construct();
        add_filter( 'disable_months_dropdown', '__return_true' );
        add_filter( 'query_vars', array( $this, 'add_custom_query_var' ) );
        add_filter( 'views_edit-product', array( $this, 'product_views' ) );
        add_filter( 'get_search_query', array( $this, 'search_label' ) );
        add_filter( 'posts_clauses', array( $this, 'posts_clauses' ), 10, 2 );
    }

    /**
     * Render blank state.
     */
    protected function render_blank_state() {
        echo '<div class="woocommerce-BlankState">';

        echo '<h2 class="woocommerce-BlankState-message">' . esc_html__( 'Ready to start selling something awesome?', 'woocommerce' ) . '</h2>';

        echo '<div class="woocommerce-BlankState-buttons">';

        echo '<a class="woocommerce-BlankState-cta button-primary button" href="' . esc_url( admin_url( 'post-new.php?post_type=product&tutorial=true' ) ) . '">' . esc_html__( 'Create Product', 'woocommerce' ) . '</a>';
        echo '<a class="woocommerce-BlankState-cta button" href="' . esc_url( admin_url( 'edit.php?post_type=product&page=product_importer' ) ) . '">' . esc_html__( 'Start Import', 'woocommerce' ) . '</a>';

        echo '</div>';

        do_action( 'wc_marketplace_suggestions_products_empty_state' );

        echo '</div>';
    }

    /**
     * Define primary column.
     *
     * @return string
     */
    protected function get_primary_column() {
        return 'name';
    }

    /**
     * Get row actions to show in the list table.
     *
     * @param array   $actions Array of actions.
     * @param WP_Post $post Current post object.
     * @return array
     */
    protected function get_row_actions( $actions, $post ) {
        /* translators: %d: product ID. */
        return array_merge( array( 'id' => sprintf( __( 'ID: %d', 'woocommerce' ), $post->ID ) ), $actions );
    }

    /**
     * Define which columns are sortable.
     *
     * @param array $columns Existing columns.
     * @return array
     */
    public function define_sortable_columns( $columns ) {
        $custom = array(
            'price' => 'price',
            'sku'   => 'sku',
            'name'  => 'title',
        );
        return wp_parse_args( $custom, $columns );
    }

    /**
     * Define which columns to show on this screen.
     *
     * @param array $columns Existing columns.
     * @return array
     */
    public function define_columns( $columns ) {
        if ( empty( $columns ) && ! is_array( $columns ) ) {
            $columns = array();
        }

        unset( $columns['title'], $columns['comments'], $columns['date'] );

        $show_columns          = array();
        $show_columns['cb']    = '<input type="checkbox" />';
        $show_columns['thumb'] = '<span class="wc-image tips" data-tip="' . esc_attr__( 'Image', 'woocommerce' ) . '">' . __( 'Image', 'woocommerce' ) . '</span>';
        $show_columns['name']  = __( 'Name', 'woocommerce' );

        if ( wc_product_sku_enabled() ) {
            $show_columns['sku'] = __( 'SKU', 'woocommerce' );
        }

        if ( 'yes' === get_option( 'woocommerce_manage_stock' ) ) {
            $show_columns['is_in_stock'] = __( 'Stock', 'woocommerce' );
        }

        $show_columns['price']       = __( 'Price', 'woocommerce' );
        $show_columns['product_cat'] = __( 'Categories', 'woocommerce' );
        $show_columns['product_tag'] = __( 'Tags', 'woocommerce' );
        $show_columns['featured']    = '<span class="wc-featured parent-tips" data-tip="' . esc_attr__( 'Featured', 'woocommerce' ) . '">' . __( 'Featured', 'woocommerce' ) . '</span>';
        $show_columns['date']        = __( 'Date', 'woocommerce' );

        return array_merge( $show_columns, $columns );
    }

    /**
     * Pre-fetch any data for the row each column has access to it. the_product global is there for bw compat.
     *
     * @param int $post_id Post ID being shown.
     */
    protected function prepare_row_data( $post_id ) {
        global $the_product;

        if ( empty( $this->object ) || $this->object->get_id() !== $post_id ) {
            $the_product  = wc_get_product( $post_id );
            $this->object = $the_product;
        }
    }

    /**
     * Render columm: thumb.
     */
    protected function render_thumb_column() {
        echo '<a href="' . esc_url( get_edit_post_link( $this->object->get_id() ) ) . '">' . $this->object->get_image( 'thumbnail' ) . '</a>'; // WPCS: XSS ok.
    }

    /**
     * Render column: name.
     */
    protected function render_name_column() {
        global $post;

        $edit_link = get_edit_post_link( $this->object->get_id() );
        $title     = _draft_or_post_title();

        echo '<strong><a class="row-title" href="' . esc_url( $edit_link ) . '">' . esc_html( $title ) . '</a>';

        _post_states( $post );

        echo '</strong>';

        if ( $this->object->get_parent_id() > 0 ) {
            echo '&nbsp;&nbsp;&larr; <a href="' . esc_url( get_edit_post_link( $this->object->get_parent_id() ) ) . '">' . get_the_title( $this->object->get_parent_id() ) . '</a>'; // @codingStandardsIgnoreLine.
        }

        get_inline_data( $post );

        /* Custom inline data for woocommerce. */
        echo '
            <div class="hidden" id="woocommerce_inline_' . absint( $this->object->get_id() ) . '">
                <div class="menu_order">' . esc_html( $this->object->get_menu_order() ) . '</div>
                <div class="sku">' . esc_html( $this->object->get_sku() ) . '</div>
                <div class="regular_price">' . esc_html( $this->object->get_regular_price() ) . '</div>
                <div class="sale_price">' . esc_html( $this->object->get_sale_price() ) . '</div>
                <div class="weight">' . esc_html( $this->object->get_weight() ) . '</div>
                <div class="length">' . esc_html( $this->object->get_length() ) . '</div>
                <div class="width">' . esc_html( $this->object->get_width() ) . '</div>
                <div class="height">' . esc_html( $this->object->get_height() ) . '</div>
                <div class="shipping_class">' . esc_html( $this->object->get_shipping_class() ) . '</div>
                <div class="visibility">' . esc_html( $this->object->get_catalog_visibility() ) . '</div>
                <div class="stock_status">' . esc_html( $this->object->get_stock_status() ) . '</div>
                <div class="stock">' . esc_html( $this->object->get_stock_quantity() ) . '</div>
                <div class="manage_stock">' . esc_html( wc_bool_to_string( $this->object->get_manage_stock() ) ) . '</div>
                <div class="featured">' . esc_html( wc_bool_to_string( $this->object->get_featured() ) ) . '</div>
                <div class="product_type">' . esc_html( $this->object->get_type() ) . '</div>
                <div class="product_is_virtual">' . esc_html( wc_bool_to_string( $this->object->get_virtual() ) ) . '</div>
                <div class="tax_status">' . esc_html( $this->object->get_tax_status() ) . '</div>
                <div class="tax_class">' . esc_html( $this->object->get_tax_class() ) . '</div>
                <div class="backorders">' . esc_html( $this->object->get_backorders() ) . '</div>
                <div class="low_stock_amount">' . esc_html( $this->object->get_low_stock_amount() ) . '</div>
            </div>
        ';
    }

    /**
     * Render columm: sku.
     */
    protected function render_sku_column() {
        echo $this->object->get_sku() ? esc_html( $this->object->get_sku() ) : '<span class="na">&ndash;</span>';
    }

    /**
     * Render columm: price.
     */
    protected function render_price_column() {
        echo $this->object->get_price_html() ? wp_kses_post( $this->object->get_price_html() ) : '<span class="na">&ndash;</span>';
    }

    /**
     * Render columm: product_cat.
     */
    protected function render_product_cat_column() {
        $terms = get_the_terms( $this->object->get_id(), 'product_cat' );
        if ( ! $terms ) {
            echo '<span class="na">&ndash;</span>';
        } else {
            $termlist = array();
            foreach ( $terms as $term ) {
                $termlist[] = '<a href="' . esc_url( admin_url( 'edit.php?product_cat=' . $term->slug . '&post_type=product' ) ) . ' ">' . esc_html( $term->name ) . '</a>';
            }

            echo apply_filters( 'woocommerce_admin_product_term_list', implode( ', ', $termlist ), 'product_cat', $this->object->get_id(), $termlist, $terms ); // WPCS: XSS ok.
        }
    }

    /**
     * Render columm: product_tag.
     */
    protected function render_product_tag_column() {
        $terms = get_the_terms( $this->object->get_id(), 'product_tag' );
        if ( ! $terms ) {
            echo '<span class="na">&ndash;</span>';
        } else {
            $termlist = array();
            foreach ( $terms as $term ) {
                $termlist[] = '<a href="' . esc_url( admin_url( 'edit.php?product_tag=' . $term->slug . '&post_type=product' ) ) . ' ">' . esc_html( $term->name ) . '</a>';
            }

            echo apply_filters( 'woocommerce_admin_product_term_list', implode( ', ', $termlist ), 'product_tag', $this->object->get_id(), $termlist, $terms ); // WPCS: XSS ok.
        }
    }

    /**
     * Render columm: featured.
     */
    protected function render_featured_column() {
        $url = wp_nonce_url( admin_url( 'admin-ajax.php?action=woocommerce_feature_product&product_id=' . $this->object->get_id() ), 'woocommerce-feature-product' );
        echo '<a href="' . esc_url( $url ) . '" aria-label="' . esc_attr__( 'Toggle featured', 'woocommerce' ) . '">';
        if ( $this->object->is_featured() ) {
            echo '<span class="wc-featured tips" data-tip="' . esc_attr__( 'Yes', 'woocommerce' ) . '">' . esc_html__( 'Yes', 'woocommerce' ) . '</span>';
        } else {
            echo '<span class="wc-featured not-featured tips" data-tip="' . esc_attr__( 'No', 'woocommerce' ) . '">' . esc_html__( 'No', 'woocommerce' ) . '</span>';
        }
        echo '</a>';
    }

    /**
     * Render columm: is_in_stock.
     */
    protected function render_is_in_stock_column() {
        if ( $this->object->is_on_backorder() ) {
            $stock_html = '<mark class="onbackorder">' . __( 'On backorder', 'woocommerce' ) . '</mark>';
        } elseif ( $this->object->is_in_stock() ) {
            $stock_html = '<mark class="instock">' . __( 'In stock', 'woocommerce' ) . '</mark>';
        } else {
            $stock_html = '<mark class="outofstock">' . __( 'Out of stock', 'woocommerce' ) . '</mark>';
        }

        if ( $this->object->managing_stock() ) {
            $stock_html .= ' (' . wc_stock_amount( $this->object->get_stock_quantity() ) . ')';
        }

        echo wp_kses_post( apply_filters( 'woocommerce_admin_stock_html', $stock_html, $this->object ) );
    }

    /**
     * Query vars for custom searches.
     *
     * @param mixed $public_query_vars Array of query vars.
     * @return array
     */
    public function add_custom_query_var( $public_query_vars ) {
        $public_query_vars[] = 'sku';
        return $public_query_vars;
    }

    /**
     * Render any custom filters and search inputs for the list table.
     */
    protected function render_filters() {
        $filters = apply_filters(
            'woocommerce_products_admin_list_table_filters',
            array(
                'product_category' => array( $this, 'render_products_category_filter' ),
                'product_type'     => array( $this, 'render_products_type_filter' ),
                'stock_status'     => array( $this, 'render_products_stock_status_filter' ),
            )
        );

        ob_start();
        foreach ( $filters as $filter_callback ) {
            call_user_func( $filter_callback );
        }
        $output = ob_get_clean();

        echo apply_filters( 'woocommerce_product_filters', $output ); // WPCS: XSS ok.
    }

    /**
     * Render the product category filter for the list table.
     *
     * @since 3.5.0
     */
    protected function render_products_category_filter() {
        $categories_count = (int) wp_count_terms( 'product_cat' );

        if ( $categories_count <= apply_filters( 'woocommerce_product_category_filter_threshold', 100 ) ) {
            wc_product_dropdown_categories(
                array(
                    'option_select_text' => __( 'Filter by category', 'woocommerce' ),
                    'hide_empty'         => 0,
                )
            );
        } else {
            $current_category_slug = isset( $_GET['product_cat'] ) ? wc_clean( wp_unslash( $_GET['product_cat'] ) ) : false; // WPCS: input var ok, CSRF ok.
            $current_category      = $current_category_slug ? get_term_by( 'slug', $current_category_slug, 'product_cat' ) : false;
            ?>
            <select class="wc-category-search" name="product_cat" data-placeholder="<?php esc_attr_e( 'Filter by category', 'woocommerce' ); ?>" data-allow_clear="true">
                <?php if ( $current_category_slug && $current_category ) : ?>
                    <option value="<?php echo esc_attr( $current_category_slug ); ?>" selected="selected"><?php echo esc_html( htmlspecialchars( wp_kses_post( $current_category->name ) ) ); ?><option>
                <?php endif; ?>
            </select>
            <?php
        }
    }

    /**
     * Render the product type filter for the list table.
     *
     * @since 3.5.0
     */
    protected function render_products_type_filter() {
        $current_product_type = isset( $_REQUEST['product_type'] ) ? wc_clean( wp_unslash( $_REQUEST['product_type'] ) ) : false; // WPCS: input var ok, sanitization ok.
        $output               = '<select name="product_type" id="dropdown_product_type"><option value="">' . esc_html__( 'Filter by product type', 'woocommerce' ) . '</option>';

        foreach ( wc_get_product_types() as $value => $label ) {
            $output .= '<option value="' . esc_attr( $value ) . '" ';
            $output .= selected( $value, $current_product_type, false );
            $output .= '>' . esc_html( $label ) . '</option>';

            if ( 'simple' === $value ) {

                $output .= '<option value="downloadable" ';
                $output .= selected( 'downloadable', $current_product_type, false );
                $output .= '> ' . ( is_rtl() ? '&larr;' : '&rarr;' ) . ' ' . esc_html__( 'Downloadable', 'woocommerce' ) . '</option>';

                $output .= '<option value="virtual" ';
                $output .= selected( 'virtual', $current_product_type, false );
                $output .= '> ' . ( is_rtl() ? '&larr;' : '&rarr;' ) . ' ' . esc_html__( 'Virtual', 'woocommerce' ) . '</option>';
            }
        }

        $output .= '</select>';
        echo $output; // WPCS: XSS ok.
    }

    /**
     * Render the stock status filter for the list table.
     *
     * @since 3.5.0
     */
    public function render_products_stock_status_filter() {
        $current_stock_status = isset( $_REQUEST['stock_status'] ) ? wc_clean( wp_unslash( $_REQUEST['stock_status'] ) ) : false; // WPCS: input var ok, sanitization ok.
        $stock_statuses       = wc_get_product_stock_status_options();
        $output               = '<select name="stock_status"><option value="">' . esc_html__( 'Filter by stock status', 'woocommerce' ) . '</option>';

        foreach ( $stock_statuses as $status => $label ) {
            $output .= '<option ' . selected( $status, $current_stock_status, false ) . ' value="' . esc_attr( $status ) . '">' . esc_html( $label ) . '</option>';
        }

        $output .= '</select>';
        echo $output; // WPCS: XSS ok.
    }

    /**
     * Search by SKU or ID for products.
     *
     * @deprecated 4.4.0 Logic moved to query_filters.
     * @param string $where Where clause SQL.
     * @return string
     */
    public function sku_search( $where ) {
        wc_deprecated_function( 'WC_Admin_List_Table_Products::sku_search', '4.4.0', 'Logic moved to query_filters.' );
        return $where;
    }

    /**
     * Change views on the edit product screen.
     *
     * @param  array $views Array of views.
     * @return array
     */
    public function product_views( $views ) {
        global $wp_query;

        // Products do not have authors.
        unset( $views['mine'] );

        // Add sorting link.
        if ( current_user_can( 'edit_others_products' ) ) {
            $class            = ( isset( $wp_query->query['orderby'] ) && 'menu_order title' === $wp_query->query['orderby'] ) ? 'current' : '';
            $query_string     = remove_query_arg( array( 'orderby', 'order' ) );
            $query_string     = add_query_arg( 'orderby', rawurlencode( 'menu_order title' ), $query_string );
            $query_string     = add_query_arg( 'order', rawurlencode( 'ASC' ), $query_string );
            $views['byorder'] = '<a href="' . esc_url( $query_string ) . '" class="' . esc_attr( $class ) . '">' . __( 'Sorting', 'woocommerce' ) . '</a>';
        }

        return $views;
    }

    /**
     * Change the label when searching products
     *
     * @param string $query Search Query.
     * @return string
     */
    public function search_label( $query ) {
        global $pagenow, $typenow;

        if ( 'edit.php' !== $pagenow || 'product' !== $typenow || ! get_query_var( 'product_search' ) || ! isset( $_GET['s'] ) ) { // WPCS: input var ok.
            return $query;
        }

        return wc_clean( wp_unslash( $_GET['s'] ) ); // WPCS: input var ok, sanitization ok.
    }

    /**
     * Handle any custom filters.
     *
     * @param array $query_vars Query vars.
     * @return array
     */
    protected function query_filters( $query_vars ) {
        $this->remove_ordering_args();
        // Custom order by arguments.
        if ( isset( $query_vars['orderby'] ) ) {
            $orderby = strtolower( $query_vars['orderby'] );
            $order   = isset( $query_vars['order'] ) ? strtoupper( $query_vars['order'] ) : 'DESC';

            if ( 'price' === $orderby ) {
                $callback = 'DESC' === $order ? 'order_by_price_desc_post_clauses' : 'order_by_price_asc_post_clauses';
                add_filter( 'posts_clauses', array( $this, $callback ) );
            }

            if ( 'sku' === $orderby ) {
                $callback = 'DESC' === $order ? 'order_by_sku_desc_post_clauses' : 'order_by_sku_asc_post_clauses';
                add_filter( 'posts_clauses', array( $this, $callback ) );
            }
        }

        // Type filtering.
        if ( isset( $query_vars['product_type'] ) ) {
            if ( 'downloadable' === $query_vars['product_type'] ) {
                $query_vars['product_type'] = '';
                add_filter( 'posts_clauses', array( $this, 'filter_downloadable_post_clauses' ) );
            } elseif ( 'virtual' === $query_vars['product_type'] ) {
                $query_vars['product_type'] = '';
                add_filter( 'posts_clauses', array( $this, 'filter_virtual_post_clauses' ) );
            }
        }

        // Stock status filter.
        if ( ! empty( $_GET['stock_status'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
            add_filter( 'posts_clauses', array( $this, 'filter_stock_status_post_clauses' ) );
        }

        // Shipping class taxonomy.
        if ( ! empty( $_GET['product_shipping_class'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
            $query_vars['tax_query'][] = array(
                'taxonomy' => 'product_shipping_class',
                'field'    => 'slug',
                'terms'    => sanitize_title( wp_unslash( $_GET['product_shipping_class'] ) ),
                'operator' => 'IN',
            );
        }

        // Search using CRUD.
        if ( ! empty( $query_vars['s'] ) ) {
            $data_store                   = WC_Data_Store::load( 'product' );
            $ids                          = $data_store->search_products( wc_clean( wp_unslash( $query_vars['s'] ) ), '', true, true );
            $query_vars['post__in']       = array_merge( $ids, array( 0 ) );
            $query_vars['product_search'] = true;
            unset( $query_vars['s'] );
        }

        return $query_vars;
    }

    /**
     * Undocumented function
     *
     * @param array    $args  Array of SELECT statement pieces (from, where, etc).
     * @param WP_Query $query WP_Query instance.
     * @return array
     */
    public function posts_clauses( $args, $query ) {

        return $args;
    }

    /**
     * Remove ordering queries.
     *
     * @param array $posts Posts array, keeping this for backwards compatibility defaulting to empty array.
     * @return array
     */
    public function remove_ordering_args( $posts = array() ) {
        remove_filter( 'posts_clauses', array( $this, 'order_by_price_asc_post_clauses' ) );
        remove_filter( 'posts_clauses', array( $this, 'order_by_price_desc_post_clauses' ) );
        remove_filter( 'posts_clauses', array( $this, 'order_by_sku_asc_post_clauses' ) );
        remove_filter( 'posts_clauses', array( $this, 'order_by_sku_desc_post_clauses' ) );
        remove_filter( 'posts_clauses', array( $this, 'filter_downloadable_post_clauses' ) );
        remove_filter( 'posts_clauses', array( $this, 'filter_virtual_post_clauses' ) );
        remove_filter( 'posts_clauses', array( $this, 'filter_stock_status_post_clauses' ) );
        return $posts; // Keeping this here for backward compatibility.
    }

    /**
     * Handle numeric price sorting.
     *
     * @param array $args Query args.
     * @return array
     */
    public function order_by_price_asc_post_clauses( $args ) {
        $args['join']    = $this->append_product_sorting_table_join( $args['join'] );
        $args['orderby'] = ' wc_product_meta_lookup.min_price ASC, wc_product_meta_lookup.product_id ASC ';
        return $args;
    }

    /**
     * Handle numeric price sorting.
     *
     * @param array $args Query args.
     * @return array
     */
    public function order_by_price_desc_post_clauses( $args ) {
        $args['join']    = $this->append_product_sorting_table_join( $args['join'] );
        $args['orderby'] = ' wc_product_meta_lookup.max_price DESC, wc_product_meta_lookup.product_id DESC ';
        return $args;
    }

    /**
     * Handle sku sorting.
     *
     * @param array $args Query args.
     * @return array
     */
    public function order_by_sku_asc_post_clauses( $args ) {
        $args['join']    = $this->append_product_sorting_table_join( $args['join'] );
        $args['orderby'] = ' wc_product_meta_lookup.sku ASC, wc_product_meta_lookup.product_id ASC ';
        return $args;
    }

    /**
     * Handle sku sorting.
     *
     * @param array $args Query args.
     * @return array
     */
    public function order_by_sku_desc_post_clauses( $args ) {
        $args['join']    = $this->append_product_sorting_table_join( $args['join'] );
        $args['orderby'] = ' wc_product_meta_lookup.sku DESC, wc_product_meta_lookup.product_id DESC ';
        return $args;
    }

    /**
     * Filter by type.
     *
     * @param array $args Query args.
     * @return array
     */
    public function filter_downloadable_post_clauses( $args ) {
        $args['join']   = $this->append_product_sorting_table_join( $args['join'] );
        $args['where'] .= ' AND wc_product_meta_lookup.downloadable=1 ';
        return $args;
    }

    /**
     * Filter by type.
     *
     * @param array $args Query args.
     * @return array
     */
    public function filter_virtual_post_clauses( $args ) {
        $args['join']   = $this->append_product_sorting_table_join( $args['join'] );
        $args['where'] .= ' AND wc_product_meta_lookup.virtual=1 ';
        return $args;
    }

    /**
     * Filter by stock status.
     *
     * @param array $args Query args.
     * @return array
     */
    public function filter_stock_status_post_clauses( $args ) {
        global $wpdb;
        if ( ! empty( $_GET['stock_status'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
            $args['join']   = $this->append_product_sorting_table_join( $args['join'] );
            $args['where'] .= $wpdb->prepare( ' AND wc_product_meta_lookup.stock_status=%s ', wc_clean( wp_unslash( $_GET['stock_status'] ) ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
        }
        return $args;
    }

    /**
     * Join wc_product_meta_lookup to posts if not already joined.
     *
     * @param string $sql SQL join.
     * @return string
     */
    private function append_product_sorting_table_join( $sql ) {
        global $wpdb;

        if ( ! strstr( $sql, 'wc_product_meta_lookup' ) ) {
            $sql .= " LEFT JOIN {$wpdb->wc_product_meta_lookup} wc_product_meta_lookup ON $wpdb->posts.ID = wc_product_meta_lookup.product_id ";
        }
        return $sql;
    }

    /**
     * Modifies post query so that it includes parent products whose variations have particular shipping class assigned.
     *
     * @param array    $pieces   Array of SELECT statement pieces (from, where, etc).
     * @param WP_Query $wp_query WP_Query instance.
     * @return array             Array of products, including parents of variations.
     */
    public function add_variation_parents_for_shipping_class( $pieces, $wp_query ) {
        global $wpdb;
        if ( isset( $_GET['product_shipping_class'] ) && '0' !== $_GET['product_shipping_class'] ) { // WPCS: input var ok.
            $replaced_where   = str_replace( ".post_type = 'product'", ".post_type = 'product_variation'", $pieces['where'] );
            $pieces['where'] .= " OR {$wpdb->posts}.ID in (
                SELECT {$wpdb->posts}.post_parent FROM
                {$wpdb->posts} LEFT JOIN {$wpdb->term_relationships} ON ({$wpdb->posts}.ID = {$wpdb->term_relationships}.object_id)
                WHERE 1=1 $replaced_where
            )";
            return $pieces;
        }
        return $pieces;
    }

}