Combine.php

<?php

/**
 * @file
 * Definition of Drupal\views\Plugin\views\filter\Combine.
 */
namespace Drupal\views\Plugin\views\filter;

use Drupal\Core\Annotation\Plugin;

/**
 * Filter handler which allows to search on multiple fields.
 *
 * @ingroup views_field_handlers
 *
 * @Plugin(
 *   id = "combine"
 * )
 */
class Combine extends String {

  /**
   * @var views_plugin_query_default
   */
  var $query;
  protected function defineOptions() {
    $options = parent::defineOptions();
    $options['fields'] = array(
      'default' => array(),
    );
    return $options;
  }
  public function buildOptionsForm(&$form, &$form_state) {
    parent::buildOptionsForm($form, $form_state);
    $this->view
      ->initStyle();

    // Allow to choose all fields as possible
    if ($this->view->style_plugin
      ->usesFields()) {
      $options = array();
      foreach ($this->view->display_handler
        ->getHandlers('field') as $name => $field) {
        $options[$name] = $field
          ->adminLabel(TRUE);
      }
      if ($options) {
        $form['fields'] = array(
          '#type' => 'select',
          '#title' => t('Choose fields to combine for filtering'),
          '#description' => t("This filter doesn't work for very special field handlers."),
          '#multiple' => TRUE,
          '#options' => $options,
          '#default_value' => $this->options['fields'],
        );
      }
      else {
        form_set_error('', t('You have to add some fields to be able to use this filter.'));
      }
    }
  }
  public function query() {
    $this->view
      ->_build('field');
    $fields = array();

    // Only add the fields if they have a proper field and table alias.
    foreach ($this->options['fields'] as $id) {
      $field = $this->view->field[$id];

      // Always add the table of the selected fields to be sure a table alias exists.
      $field
        ->ensureMyTable();
      if (!empty($field->field_alias) && !empty($field->field_alias)) {
        $fields[] = "{$field->tableAlias}.{$field->realField}";
      }
    }
    if ($fields) {
      $count = count($fields);
      $separated_fields = array();
      foreach ($fields as $key => $field) {
        $separated_fields[] = $field;
        if ($key < $count - 1) {
          $separated_fields[] = "' '";
        }
      }
      $expression = implode(', ', $separated_fields);
      $expression = "CONCAT_WS(' ', {$expression})";
      $info = $this
        ->operators();
      if (!empty($info[$this->operator]['method'])) {
        $this
          ->{$info[$this->operator]['method']}($expression);
      }
    }
  }

  // By default things like op_equal uses add_where, that doesn't support
  // complex expressions, so override all operators.
  function op_equal($field) {
    $placeholder = $this
      ->placeholder();
    $operator = $this
      ->operator();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} {$operator} {$placeholder}", array(
      $placeholder => $this->value,
    ));
  }
  function op_contains($field) {
    $placeholder = $this
      ->placeholder();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} LIKE {$placeholder}", array(
      $placeholder => '%' . db_like($this->value) . '%',
    ));
  }
  function op_starts($field) {
    $placeholder = $this
      ->placeholder();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} LIKE {$placeholder}", array(
      $placeholder => db_like($this->value) . '%',
    ));
  }
  function op_not_starts($field) {
    $placeholder = $this
      ->placeholder();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} NOT LIKE {$placeholder}", array(
      $placeholder => db_like($this->value) . '%',
    ));
  }
  function op_ends($field) {
    $placeholder = $this
      ->placeholder();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} LIKE {$placeholder}", array(
      $placeholder => '%' . db_like($this->value),
    ));
  }
  function op_not_ends($field) {
    $placeholder = $this
      ->placeholder();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} NOT LIKE {$placeholder}", array(
      $placeholder => '%' . db_like($this->value),
    ));
  }
  function op_not($field) {
    $placeholder = $this
      ->placeholder();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} NOT LIKE {$placeholder}", array(
      $placeholder => '%' . db_like($this->value) . '%',
    ));
  }
  function op_regex($field) {
    $placeholder = $this
      ->placeholder();
    $this->query
      ->add_where_expression($this->options['group'], "{$field} RLIKE {$placeholder}", array(
      $placeholder => $this->value,
    ));
  }
  function op_empty($field) {
    if ($this->operator == 'empty') {
      $operator = "IS NULL";
    }
    else {
      $operator = "IS NOT NULL";
    }
    $this->query
      ->add_where_expression($this->options['group'], "{$field} {$operator}");
  }

}