Display Suite's output modification in order to add a new class under certain circumstances #drupal #displaysuite

module-name.module

<?php 

/**
 * Implements hook_theme_registry_alter().
 */
function feature_blog_theme_registry_alter(&$theme_registry) {
  $theme_registry['node']['preprocess functions'][] = 'onecolumn_class_node_preprocess';
}

/*
* Preprocess function for node.
* Added in feature_blog_theme_registry_alter()
*/
function onecolumn_class_node_preprocess(&$vars){
  // If there's no content on the left column,
  // we'll add a class to the node, for special CSS.
  if ($vars['type'] == 'blog' && $vars['view_mode'] == 'teaser' && !$vars['left']) {
    $vars['classes_array'][] = 'onecolumn';
  }
}

We have to make sure that this module is loaded the last one in order to make sure that the new preprocess function gets loaded the last one.

This can be achieved by creating the following hook_update in module's module.install file:

<?php

/**
 * Increments nameofthemodule module's weight in system table.
 */
function nameofthemodule_update_7001(&$sandbox = NULL) {
  $fields = array(
      'weight' => '10',
    );

  db_update('system')
  ->fields($fields)
  ->condition('name', 'feature_blog')
  ->execute();
}