Formula.php

<?php

/**
 * @file
 * Definition of Drupal\views\Plugin\views\argument\Formula.
 */
namespace Drupal\views\Plugin\views\argument;

use Drupal\Component\Annotation\PluginID;
use Drupal\views\Plugin\views\display\DisplayPluginBase;
use Drupal\views\ViewExecutable;

/**
 * Abstract argument handler for simple formulae.
 *
 * Child classes of this object should implement summaryArgument, at least.
 *
 * Definition terms:
 * - formula: The formula to use for this handler.
 *
 * @ingroup views_argument_handlers
 *
 * @PluginID("formula")
 */
class Formula extends ArgumentPluginBase {
  var $formula = NULL;

  /**
   * Overrides Drupal\views\Plugin\views\argument\ArgumentPluginBase::init().
   */
  public function init(ViewExecutable $view, DisplayPluginBase $display, array &$options = NULL) {
    parent::init($view, $display, $options);
    if (!empty($this->definition['formula'])) {
      $this->formula = $this->definition['formula'];
    }
  }
  public function getFormula() {
    return str_replace('***table***', $this->tableAlias, $this->formula);
  }

  /**
   * Build the summary query based on a formula
   */
  protected function summaryQuery() {
    $this
      ->ensureMyTable();

    // Now that our table is secure, get our formula.
    $formula = $this
      ->getFormula();

    // Add the field.
    $this->base_alias = $this->name_alias = $this->query
      ->addField(NULL, $formula, $this->field);
    $this->query
      ->set_count_field(NULL, $formula, $this->field);
    return $this
      ->summaryBasics(FALSE);
  }

  /**
   * Build the query based upon the formula
   */
  public function query($group_by = FALSE) {
    $this
      ->ensureMyTable();

    // Now that our table is secure, get our formula.
    $placeholder = $this
      ->placeholder();
    $formula = $this
      ->getFormula() . ' = ' . $placeholder;
    $placeholders = array(
      $placeholder => $this->argument,
    );
    $this->query
      ->addWhere(0, $formula, $placeholders, 'formula');
  }

}