memcache.install

<?php

/**
 * Implements hook_requirements().
 */
function memcache_requirements($phase) {
  $requirements = [];

  $memcache = extension_loaded('memcache');
  $memcached = extension_loaded('memcached');

  if ($phase == 'install' || $phase == 'runtime') {
    if (!$memcache && !$memcached) {
      $requirements['memcache_extension']['severity'] = REQUIREMENT_ERROR;
      $requirements['memcache_extension']['title'] = t('Extensions not available');
      $requirements['memcache_extension']['value'] = t('Either the <a href="http://php.net/manual/en/book.memcache.php">memcache</a> or <a href="http://php.net/manual/en/book.memcached.php">memcached</a> extensions must be installed in order to use memcache integration.');
    }
  }

  if ($phase == 'runtime') {
    if ($memcache) {
      // @todo: consider adding minimum version requirement for extensions.
      $requirements['memcache_extension_version']['severity'] = REQUIREMENT_OK;
      $requirements['memcache_extension_version']['title'] = t('Memcache version');
      $requirements['memcache_extension_version']['value'] = phpversion('memcache');
    }
    if ($memcached) {
      $requirements['memcached_extension_version']['severity'] = REQUIREMENT_OK;
      $requirements['memcached_extension_version']['title'] = t('Memcached version');
      $requirements['memcached_extension_version']['value'] = phpversion('memcached');
    }
  }

  return $requirements;
}