Merge pull request #3357 from eileenmcnaughton/CRM-14743

[civicrm-core.git] / CRM / Utils / System.php

<?php
/*
 +--------------------------------------------------------------------+
 | CiviCRM version 4.5                                                |
 +--------------------------------------------------------------------+
 | Copyright CiviCRM LLC (c) 2004-2014                                |
 +--------------------------------------------------------------------+
 | This file is a part of CiviCRM.                                    |
 |                                                                    |
 | CiviCRM is free software; you can copy, modify, and distribute it  |
 | under the terms of the GNU Affero General Public License           |
 | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
 |                                                                    |
 | CiviCRM is distributed in the hope that it will be useful, but     |
 | WITHOUT ANY WARRANTY; without even the implied warranty of         |
 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
 | See the GNU Affero General Public License for more details.        |
 |                                                                    |
 | You should have received a copy of the GNU Affero General Public   |
 | License and the CiviCRM Licensing Exception along                  |
 | with this program; if not, contact CiviCRM LLC                     |
 | at info[AT]civicrm[DOT]org. If you have questions about the        |
 | GNU Affero General Public License or the licensing of CiviCRM,     |
 | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
 +--------------------------------------------------------------------+
*/

/**
 *
 * @package CRM
 * @copyright CiviCRM LLC (c) 2004-2014
 * $Id$
 *
 */

/**
 * System wide utilities.
 *
 */
class CRM_Utils_System {

  static $_callbacks = NULL;

  /**
   * @var string Page title
   */
  static $title = '';

  /**
   * Compose a new URL string from the current URL string.
   *
   * Used by all the framework components, specifically,
   * pager, sort and qfc
   *
   * @param string $urlVar
   *   The url variable being considered (i.e. crmPageID, crmSortID etc).
   * @param bool $includeReset
   *   (optional) Whether to include the reset GET string (if present).
   * @param bool $includeForce
   *   (optional) Whether to include the force GET string (if present).
   * @param string $path
   *   (optional) The path to use for the new url.
   * @param bool|string $absolute
   *   (optional) Whether to return an absolute URL.
   *
   * @return string
   *   The URL fragment.
   * @access public
   */
  static function makeURL($urlVar, $includeReset = FALSE, $includeForce = TRUE, $path = NULL, $absolute = FALSE) {
    if (empty($path)) {
      $config = CRM_Core_Config::singleton();
      $path = CRM_Utils_Array::value($config->userFrameworkURLVar, $_GET);
      if (empty($path)) {
        return '';
      }
    }

    return
      self::url(
        $path,
        CRM_Utils_System::getLinksUrl($urlVar, $includeReset, $includeForce),
        $absolute
      );
  }

  /**
   * Get the query string and clean it up.
   *
   * Strips some variables that should not be propagated, specifically variables
   * like 'reset'. Also strips any side-affect actions (e.g. export).
   *
   * This function is copied mostly verbatim from Pager.php (_getLinksUrl)
   *
   * @param string $urlVar
   *   The URL variable being considered (e.g. crmPageID, crmSortID etc).
   * @param bool $includeReset
   *   (optional) By default this is FALSE, meaning that the reset parameter
   *   is skipped. Set to TRUE to leave the reset parameter as-is.
   * @param bool $includeForce
   *   (optional)
   * @param bool $skipUFVar
   *   (optional)
   *
   * @return string
   * @access public
   */
  static function getLinksUrl($urlVar, $includeReset = FALSE, $includeForce = TRUE, $skipUFVar = TRUE) {
    // Sort out query string to prevent messy urls
    $querystring = array();
    $qs          = array();
    $arrays      = array();

    if (!empty($_SERVER['QUERY_STRING'])) {
      $qs = explode('&', str_replace('&amp;', '&', $_SERVER['QUERY_STRING']));
      for ($i = 0, $cnt = count($qs); $i < $cnt; $i++) {
        // check first if exist a pair
        if (strstr($qs[$i], '=') !== FALSE) {
          list($name, $value) = explode('=', $qs[$i]);
          if ($name != $urlVar) {
            $name = rawurldecode($name);
            //check for arrays in parameters: site.php?foo[]=1&foo[]=2&foo[]=3
            if ((strpos($name, '[') !== FALSE) &&
              (strpos($name, ']') !== FALSE)
            ) {
              $arrays[] = $qs[$i];
            }
            else {
              $qs[$name] = $value;
            }
          }
        }
        else {
          $qs[$qs[$i]] = '';
        }
        unset($qs[$i]);
      }
    }

    if ($includeForce) {
      $qs['force'] = 1;
    }

    // Ok this is a big assumption but usually works
    // If we are in snippet mode, retain the 'section' param, if not, get rid
    // of it.
    if (!empty($qs['snippet'])) {
      unset($qs['snippet']);
    }
    else {
      unset($qs['section']);
    }

    if ($skipUFVar) {
      $config = CRM_Core_Config::singleton();
      unset($qs[$config->userFrameworkURLVar]);
    }

    foreach ($qs as $name => $value) {
      if ($name != 'reset' || $includeReset) {
        $querystring[] = $name . '=' . $value;
      }
    }

    $querystring = array_merge($querystring, array_unique($arrays));

    $url = implode('&', $querystring);
    if ($urlVar) {
      $url .= (!empty($querystring) ? '&' : '') . $urlVar . '=';
    }

    return $url;
  }

  /**
   * If we are using a theming system, invoke theme, else just print the
   * content.
   *
   * @param string $content
   *   The content that will be themed.
   * @param bool $print
   *   (optional) Are we displaying to the screen or bypassing theming?
   * @param bool $maintenance
   *   (optional) For maintenance mode.
   *
   * @return string
   *
   * @access public
   */
  static function theme(
    &$content,
    $print       = FALSE,
    $maintenance = FALSE
  ) {
    $config = &CRM_Core_Config::singleton();
    return $config->userSystem->theme($content, $print, $maintenance);
  }

  /**
   * Generate a query string if input is an array.
   *
   * @param array|string $query
   * @return string
   */
  static function makeQueryString($query) {
    if (is_array($query)) {
      $buf = '';
      foreach ($query as $key => $value) {
        $buf .= ($buf ? '&' : '') . urlencode($key) . '=' . urlencode($value);
      }
      $query = $buf;
    }
    return $query;
  }

  /**
   * Generate an internal CiviCRM URL.
   *
   * @param string $path
   *   The path being linked to, such as "civicrm/add".
   * @param array|string $query
   *   A query string to append to the link, or an array of key-value pairs.
   * @param bool $absolute
   *   Whether to force the output to be an absolute link (beginning with a
   *   URI-scheme such as 'http:'). Useful for links that will be displayed
   *   outside the site, such as in an RSS feed.
   * @param string $fragment
   *   A fragment identifier (named anchor) to append to the link.
   *
   * @param bool $htmlize
   * @param bool $frontend
   * @param bool $forceBackend
   * @return string
   *   An HTML string containing a link to the given path.
   * @access public
   */
  static function url(
    $path = NULL,
    $query    = NULL,
    $absolute = FALSE,
    $fragment = NULL,
    $htmlize  = TRUE,
    $frontend = FALSE,
    $forceBackend = FALSE
  ) {
    $query = self::makeQueryString($query);

    // we have a valid query and it has not yet been transformed
    if ($htmlize && !empty($query) && strpos($query, '&amp;') === FALSE) {
      $query = htmlentities($query);
    }

    $config = CRM_Core_Config::singleton();
    return $config->userSystem->url($path, $query, $absolute, $fragment, $htmlize, $frontend, $forceBackend);
  }

  /**
   * @param $text
   * @param null $path
   * @param null $query
   * @param bool $absolute
   * @param null $fragment
   * @param bool $htmlize
   * @param bool $frontend
   * @param bool $forceBackend
   *
   * @return string
   */
  static function href($text, $path = NULL, $query = NULL, $absolute = TRUE,
    $fragment = NULL, $htmlize = TRUE, $frontend = FALSE, $forceBackend = FALSE
  ) {
    $url = self::url($path, $query, $absolute, $fragment, $htmlize, $frontend, $forceBackend);
    return "<a href=\"$url\">$text</a>";
  }

  /**
   * @return mixed
   */
  static function permissionDenied() {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->permissionDenied();
  }

  /**
   * @return mixed
   */
  static function logout() {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->logout();
  }

  // this is a very drupal specific function for now
  static function updateCategories() {
    $config = CRM_Core_Config::singleton();
    if ($config->userSystem->is_drupal) {
      $config->userSystem->updateCategories();
    }
  }

  /**
   * What menu path are we currently on. Called for the primary tpl
   *
   * @return string the current menu path
   * @access public
   */
  static function currentPath() {
    $config = CRM_Core_Config::singleton();
    return trim(CRM_Utils_Array::value($config->userFrameworkURLVar, $_GET), '/');
  }

  /**
   * This function is called from a template to compose a url.
   *
   * @param array $params
   *   List of parameters.
   *
   * @return string url
   * @access public
   */
  static function crmURL($params) {
    $p = CRM_Utils_Array::value('p', $params);
    if (!isset($p)) {
      $p = self::currentPath();
    }

    return self::url(
      $p,
      CRM_Utils_Array::value('q', $params),
      CRM_Utils_Array::value('a', $params, FALSE),
      CRM_Utils_Array::value('f', $params),
      CRM_Utils_Array::value('h', $params, TRUE),
      CRM_Utils_Array::value('fe', $params, FALSE),
      CRM_Utils_Array::value('fb', $params, FALSE)
    );
  }

  /**
   * Sets the title of the page.
   *
   * @param string $title
   * @param string $pageTitle
   *
   * @access public
   */
  static function setTitle($title, $pageTitle = NULL) {
    self::$title = $title;
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->setTitle($title, $pageTitle);
  }

  /**
   * Figures and sets the userContext.
   *
   * Uses the referer if valid else uses the default.
   *
   * @param array $names
   *   Refererer should match any str in this array.
   * @param string $default
   *   (optional) The default userContext if no match found.
   *
   * @access public
   */
  static function setUserContext($names, $default = NULL) {
    $url = $default;

    $session = CRM_Core_Session::singleton();
    $referer = CRM_Utils_Array::value('HTTP_REFERER', $_SERVER);

    if ($referer && !empty($names)) {
      foreach ($names as $name) {
        if (strstr($referer, $name)) {
          $url = $referer;
          break;
        }
      }
    }

    if ($url) {
      $session->pushUserContext($url);
    }
  }

  /**
   * Gets a class name for an object.
   *
   * @param object $object
   *   Object whose class name is needed.
   *
   * @return string
   *   The class name of the object.
   *
   * @access public
   */
  static function getClassName($object) {
    return get_class($object);
  }

  /**
   * Redirect to another URL.
   *
   * @param string $url
   *   The URL to provide to the browser via the Location header.
   *
   * @access public
   */
  static function redirect($url = NULL) {
    if (!$url) {
      $url = self::url('civicrm/dashboard', 'reset=1');
    }

    // replace the &amp; characters with &
    // this is kinda hackish but not sure how to do it right
    $url = str_replace('&amp;', '&', $url);

    // If we are in a json context, respond appropriately
    if (CRM_Utils_Array::value('snippet', $_GET) === 'json') {
      CRM_Core_Page_AJAX::returnJsonResponse(array(
        'status' => 'redirect',
        'userContext' => $url,
      ));
    }

    header('Location: ' . $url);
    self::civiExit();
  }

  /**
   * Redirect to another URL using JavaScript.
   *
   * Use an html based file with javascript embedded to redirect to another url
   * This prevent the too many redirect errors emitted by various browsers
   *
   * @param string $url
   *   (optional) The destination URL.
   * @param string $title
   *   (optional) The page title to use for the redirect page.
   * @param string $message
   *   (optional) The message to provide in the body of the redirect page.
   *
   * @access public
   */
  static function jsRedirect(
    $url     = NULL,
    $title   = NULL,
    $message = NULL
  ) {
    if (!$url) {
      $url = self::url('civicrm/dashboard', 'reset=1');
    }

    if (!$title) {
      $title = ts('CiviCRM task in progress');
    }

    if (!$message) {
      $message = ts('A long running CiviCRM task is currently in progress. This message will be refreshed till the task is completed');
    }

    // replace the &amp; characters with &
    // this is kinda hackish but not sure how to do it right
    $url = str_replace('&amp;', '&', $url);

    $template = CRM_Core_Smarty::singleton();
    $template->assign('redirectURL', $url);
    $template->assign('title', $title);
    $template->assign('message', $message);

    $html = $template->fetch('CRM/common/redirectJS.tpl');

    echo $html;

    self::civiExit();
  }

  /**
   * Append an additional breadcrumb tag to the existing breadcrumbs.
   *
   * @param $breadCrumbs
   *
   * @access public
   */
  static function appendBreadCrumb($breadCrumbs) {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->appendBreadCrumb($breadCrumbs);
  }

  /**
   * Reset an additional breadcrumb tag to the existing breadcrumb.
   *
   * @access public
   */
  static function resetBreadCrumb() {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->resetBreadCrumb();
  }

  /**
   * Append a string to the head of the HTML file.
   *
   * @param string $bc
   *
   * @access public
   */
  static function addHTMLHead($bc) {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->addHTMLHead($bc);
  }

  /**
   * Determine the post URL for a form
   *
   * @param $action
   *   The default action if one is pre-specified.
   *
   * @return string
   *   The URL to post the form.
   * @access public
   */
  static function postURL($action) {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->postURL($action);
  }

  /**
   * Rewrite various system URLs to https.
   *
   * @access public
   */
  static function mapConfigToSSL() {
    $config = CRM_Core_Config::singleton();
    $config->userFrameworkResourceURL = str_replace('http://', 'https://', $config->userFrameworkResourceURL);
    $config->resourceBase = $config->userFrameworkResourceURL;

    if (! empty($config->extensionsURL)) {
      $config->extensionsURL = str_replace('http://', 'https://', $config->extensionsURL);
    }

    return $config->userSystem->mapConfigToSSL();
  }

  /**
   * Get the base URL of the system.
   *
   * @return string
   * @access public
   */
  static function baseURL() {
    $config = CRM_Core_Config::singleton();
    return $config->userFrameworkBaseURL;
  }

  /**
   */
  static function authenticateAbort($message, $abort) {
    if ($abort) {
      echo $message;
      self::civiExit(0);
    }
    else {
      return FALSE;
    }
  }

  /**
   * @param bool $abort
   *   (optional) Whether to exit; defaults to true.
   *
   * @return bool
   */
  static function authenticateKey($abort = TRUE) {
    // also make sure the key is sent and is valid
    $key = trim(CRM_Utils_Array::value('key', $_REQUEST));

    $docAdd = "More info at:" . CRM_Utils_System::docURL2("Managing Scheduled Jobs", TRUE, NULL, NULL, NULL, "wiki");

    if (!$key) {
      return self::authenticateAbort(
        "ERROR: You need to send a valid key to execute this file. " . $docAdd . "\n",
        $abort
      );
    }

    $siteKey = defined('CIVICRM_SITE_KEY') ? CIVICRM_SITE_KEY : NULL;

    if (!$siteKey || empty($siteKey)) {
      return self::authenticateAbort(
        "ERROR: You need to set a valid site key in civicrm.settings.php. " . $docAdd . "\n",
        $abort
      );
    }

    if (strlen($siteKey) < 8) {
      return self::authenticateAbort(
        "ERROR: Site key needs to be greater than 7 characters in civicrm.settings.php. " . $docAdd . "\n",
        $abort
      );
    }

    if ($key !== $siteKey) {
      return self::authenticateAbort(
        "ERROR: Invalid key value sent. " . $docAdd . "\n",
        $abort
      );
    }

    return TRUE;
  }

  /**
   * @param bool $abort
   * @param null $name
   * @param null $pass
   * @param bool $storeInSession
   * @param bool $loadCMSBootstrap
   * @param bool $requireKey
   *
   * @return bool
   */
  static function authenticateScript($abort = TRUE, $name = NULL, $pass = NULL, $storeInSession = TRUE, $loadCMSBootstrap = TRUE, $requireKey = TRUE) {
    // auth to make sure the user has a login/password to do a shell operation
    // later on we'll link this to acl's
    if (!$name) {
      $name = trim(CRM_Utils_Array::value('name', $_REQUEST));
      $pass = trim(CRM_Utils_Array::value('pass', $_REQUEST));
    }

    // its ok to have an empty password
    if (!$name) {
      return self::authenticateAbort(
        "ERROR: You need to send a valid user name and password to execute this file\n",
        $abort
      );
    }

    if ($requireKey && !self::authenticateKey($abort)) {
      return FALSE;
    }

    $result = CRM_Utils_System::authenticate($name, $pass, $loadCMSBootstrap);
    if (!$result) {
      return self::authenticateAbort(
        "ERROR: Invalid username and/or password\n",
        $abort
      );
    }
    elseif ($storeInSession) {
      // lets store contact id and user id in session
      list($userID, $ufID, $randomNumber) = $result;
      if ($userID && $ufID) {
        $config = CRM_Core_Config::singleton();
        $config->userSystem->setUserSession( array($userID, $ufID) );
      }
      else {
        return self::authenticateAbort(
          "ERROR: Unexpected error, could not match userID and contactID",
          $abort
        );
      }
    }

    return $result;
  }

  /**
   * Authenticate the user against the uf db.
   *
   * In case of succesful authentication, returns an array consisting of
   * (contactID, ufID, unique string). Returns FALSE if authentication is
   * unsuccessful.
   *
   * @param string $name
   *   The username.
   * @param string $password
   *   The password.
   * @param bool $loadCMSBootstrap
   * @param $realPath
   *
   * @return false|array
   * @access public
   */
  static function authenticate($name, $password, $loadCMSBootstrap = FALSE, $realPath = NULL) {
    $config = CRM_Core_Config::singleton();

    /* Before we do any loading, let's start the session and write to it.
     * We typically call authenticate only when we need to bootstrap the CMS
     * directly via Civi and hence bypass the normal CMS auth and bootstrap
     * process typically done in CLI and cron scripts. See: CRM-12648
     */
    $session = CRM_Core_Session::singleton();
    $session->set( 'civicrmInitSession', TRUE );

    $dbDrupal = DB::connect($config->userFrameworkDSN);
    return $config->userSystem->authenticate($name, $password, $loadCMSBootstrap, $realPath);
  }

  /**
   * Set a message in the UF to display to a user.
   *
   * @param string $message
   *   The message to set.
   *
   * @access public
   */
  static function setUFMessage($message) {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->setMessage($message);
  }


  /**
   * Determine whether a value is null-ish.
   *
   * @param $value
   *   The value to check for null.
   * @return bool
   */
  static function isNull($value) {
    // FIXME: remove $value = 'null' string test when we upgrade our DAO code to handle passing null in a better way.
    if (!isset($value) || $value === NULL || $value === '' || $value === 'null') {
      return TRUE;
    }
    if (is_array($value)) {
      foreach ($value as $key => $value) {
        if (!self::isNull($value)) {
          return FALSE;
        }
      }
      return TRUE;
    }
    return FALSE;
  }

  /**
   * Obscure all but the last few digits of a credit card number.
   *
   * @param string $number
   *   The credit card number to obscure.
   * @param int $keep
   *   (optional) The number of digits to preserve unmodified.
   * @return string
   *   The obscured credit card number.
   */
  static function mungeCreditCard($number, $keep = 4) {
    $number = trim($number);
    if (empty($number)) {
      return NULL;
    }
    $replace = str_repeat('*', strlen($number) - $keep);
    return substr_replace($number, $replace, 0, -$keep);
  }

  /**
   * Determine which PHP modules are loaded.
   *
   * @return array
   */
  public static function parsePHPModules() {
    ob_start();
    phpinfo(INFO_MODULES);
    $s = ob_get_contents();
    ob_end_clean();

    $s        = strip_tags($s, '<h2><th><td>');
    $s        = preg_replace('/<th[^>]*>([^<]+)<\/th>/', "<info>\\1</info>", $s);
    $s        = preg_replace('/<td[^>]*>([^<]+)<\/td>/', "<info>\\1</info>", $s);
    $vTmp     = preg_split('/(<h2>[^<]+<\/h2>)/', $s, -1, PREG_SPLIT_DELIM_CAPTURE);
    $vModules = array();
    for ($i = 1; $i < count($vTmp); $i++) {
      if (preg_match('/<h2>([^<]+)<\/h2>/', $vTmp[$i], $vMat)) {
        $vName = trim($vMat[1]);
        $vTmp2 = explode("\n", $vTmp[$i + 1]);
        foreach ($vTmp2 AS $vOne) {
          $vPat  = '<info>([^<]+)<\/info>';
          $vPat3 = "/$vPat\s*$vPat\s*$vPat/";
          $vPat2 = "/$vPat\s*$vPat/";
          // 3cols
          if (preg_match($vPat3, $vOne, $vMat)) {
            $vModules[$vName][trim($vMat[1])] = array(trim($vMat[2]), trim($vMat[3]));
            // 2cols
          }
          elseif (preg_match($vPat2, $vOne, $vMat)) {
            $vModules[$vName][trim($vMat[1])] = trim($vMat[2]);
          }
        }
      }
    }
    return $vModules;
  }

  /**
   * Get a setting from a loaded PHP module.
   */
  public static function getModuleSetting($pModuleName, $pSetting) {
    $vModules = self::parsePHPModules();
    return $vModules[$pModuleName][$pSetting];
  }

  /**
   * @param $title
   *   (optional)
   *
   * @return mixed|string
   */
  static function memory($title = NULL) {
    static $pid = NULL;
    if (!$pid) {
      $pid = posix_getpid();
    }

    $memory = str_replace("\n", '', shell_exec("ps -p" . $pid . " -o rss="));
    $memory .= ", " . time();
    if ($title) {
      CRM_Core_Error::debug_var($title, $memory);
    }
    return $memory;
  }

  /**
   * @param string $name
   * @param string $mimeType
   * @param $buffer
   * @param string $ext
   * @param bool $output
   * @param string $disposition
   */
  static function download($name, $mimeType, &$buffer,
    $ext = NULL,
    $output = TRUE,
    $disposition = 'attachment'
  ) {
    $now = gmdate('D, d M Y H:i:s') . ' GMT';

    header('Content-Type: ' . $mimeType);
    header('Expires: ' . $now);

    // lem9 & loic1: IE need specific headers
    $isIE = strstr($_SERVER['HTTP_USER_AGENT'], 'MSIE');
    if ($ext) {
      $fileString = "filename=\"{$name}.{$ext}\"";
    }
    else {
      $fileString = "filename=\"{$name}\"";
    }
    if ($isIE) {
      header("Content-Disposition: inline; $fileString");
      header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
      header('Pragma: public');
    }
    else {
      header("Content-Disposition: $disposition; $fileString");
      header('Pragma: no-cache');
    }

    if ($output) {
      print $buffer;
      self::civiExit();
    }
  }

  /**
   * Gather and print (and possibly log) amount of used memory.
   *
   * @param string $title
   * @param bool $log
   *   (optional) Whether to log the memory usage information.
   */
  static function xMemory($title = NULL, $log = FALSE) {
    $mem = (float ) xdebug_memory_usage() / (float )(1024);
    $mem = number_format($mem, 5) . ", " . time();
    if ($log) {
      echo "<p>$title: $mem<p>";
      flush();
      CRM_Core_Error::debug_var($title, $mem);
    }
    else {
      echo "<p>$title: $mem<p>";
      flush();
    }
  }

  /**
   * Take a URL (or partial URL) and make it better.
   *
   * Currently, URLs pass straight through unchanged unless they are "seriously
   * malformed" (see http://us2.php.net/parse_url).
   *
   * @param string $url
   *   The URL to operate on.
   * @return string
   *   The fixed URL.
   */
  static function fixURL($url) {
    $components = parse_url($url);

    if (!$components) {
      return NULL;
    }

    // at some point we'll add code here to make sure the url is not
    // something that will mess up up, so we need to clean it up here
    return $url;
  }

  /**
   * Make sure a callback is valid in the current context.
   *
   * @param string $callback
   *   Name of the function to check.
   *
   * @return bool
   */
  static function validCallback($callback) {
    if (self::$_callbacks === NULL) {
      self::$_callbacks = array();
    }

    if (!array_key_exists($callback, self::$_callbacks)) {
      if (strpos($callback, '::') !== FALSE) {
        list($className, $methodName) = explode('::', $callback);
        $fileName = str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php';
        // ignore errors if any
        @include_once ($fileName);
        if (!class_exists($className)) {
          self::$_callbacks[$callback] = FALSE;
        }
        else {
          // instantiate the class
          $object = new $className();
          if (!method_exists($object, $methodName)) {
            self::$_callbacks[$callback] = FALSE;
          }
          else {
            self::$_callbacks[$callback] = TRUE;
          }
        }
      }
      else {
        self::$_callbacks[$callback] = function_exists($callback);
      }
    }
    return self::$_callbacks[$callback];
  }

  /**
   * Like PHP's built-in explode(), but always return an array of $limit items.
   *
   * This serves as a wrapper to the PHP explode() function. In the event that
   * PHP's explode() returns an array with fewer than $limit elements, pad
   * the end of the array with NULLs.
   *
   * @param string $separator
   * @param string $string
   * @param int $limit
   * @return string[]
   */
  static function explode($separator, $string, $limit) {
    $result = explode($separator, $string, $limit);
    for ($i = count($result); $i < $limit; $i++) {
      $result[$i] = NULL;
    }
    return $result;
  }

  /**
   * @param string $url
   *   The URL to check.
   * @param bool $addCookie
   *   (optional)
   *
   * @return mixed
   */
  static function checkURL($url, $addCookie = FALSE) {
    // make a GET request to $url
    $ch = curl_init($url);
    if ($addCookie) {
      curl_setopt($ch, CURLOPT_COOKIE, http_build_query($_COOKIE));
    }
    // it's quite alright to use a self-signed cert
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);

    // lets capture the return stuff rather than echo
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE );

    return curl_exec($ch);
  }

  /**
   * Assert that we are running on a particular PHP version.
   *
   * @param int $ver
   *   The major version of PHP that is required.
   * @param bool $abort
   *   (optional) Whether to fatally abort if the version requirement is not
   *   met. Defaults to TRUE.
   * @return bool
   *   Returns TRUE if the requirement is met, FALSE if the requirement is not
   *   met and we're not aborting due to the failed requirement. If $abort is
   *   TRUE and the requirement fails, this function does not return.
   */
  static function checkPHPVersion($ver = 5, $abort = TRUE) {
    $phpVersion = substr(PHP_VERSION, 0, 1);
    if ($phpVersion >= $ver) {
      return TRUE;
    }

    if ($abort) {
      CRM_Core_Error::fatal(ts('This feature requires PHP Version %1 or greater',
          array(1 => $ver)
        ));
    }
    return FALSE;
  }

  /**
   * @param $string
   * @param bool $encode
   *
   * @return string
   */
  static function formatWikiURL($string, $encode = FALSE) {
    $items = explode(' ', trim($string), 2);
    if (count($items) == 2) {
      $title = $items[1];
    }
    else {
      $title = $items[0];
    }

    // fix for CRM-4044
    $url = $encode ? self::urlEncode($items[0]) : $items[0];
    return "<a href=\"$url\">$title</a>";
  }

  /**
   * @param string $url
   *
   * @return null|string
   */
  static function urlEncode($url) {
    $items = parse_url($url);
    if ($items === FALSE) {
      return NULL;
    }

    if (empty($items['query'])) {
      return $url;
    }

    $items['query'] = urlencode($items['query']);

    $url = $items['scheme'] . '://';
    if (!empty($items['user'])) {
      $url .= "{$items['user']}:{$items['pass']}@";
    }

    $url .= $items['host'];
    if (!empty($items['port'])) {
      $url .= ":{$items['port']}";
    }

    $url .= "{$items['path']}?{$items['query']}";
    if (!empty($items['fragment'])) {
      $url .= "#{$items['fragment']}";
    }

    return $url;
  }

  /**
   * Return the running civicrm version.
   *
   * @return string
   *   civicrm version
   * @access public
   */
  static function version() {
    static $version;

    if (!$version) {
      $verFile = implode(DIRECTORY_SEPARATOR,
        array(dirname(__FILE__), '..', '..', 'civicrm-version.php')
      );
      if (file_exists($verFile)) {
        require_once ($verFile);
        if (function_exists('civicrmVersion')) {
          $info = civicrmVersion();
          $version = $info['version'];
        }
      }
      else {
        // svn installs don't have version.txt by default. In that case version.xml should help -
        $verFile = implode(DIRECTORY_SEPARATOR,
          array(dirname(__FILE__), '..', '..', 'xml', 'version.xml')
        );
        if (file_exists($verFile)) {
          $str     = file_get_contents($verFile);
          $xmlObj  = simplexml_load_string($str);
          $version = (string) $xmlObj->version_no;
        }
      }

      // pattern check
      if (!CRM_Utils_System::isVersionFormatValid($version)) {
        CRM_Core_Error::fatal('Unknown codebase version.');
      }
    }

    return $version;
  }

  /**
   * Determines whether a string is a valid CiviCRM version string.
   *
   * @param string $version
   *   Version string to be checked.
   * @return bool
   */
  static function isVersionFormatValid($version) {
    return preg_match("/^(\d{1,2}\.){2,3}(\d{1,2}|(alpha|beta)\d{1,2})(\.upgrade)?$/", $version);
  }

  /**
   * Wraps or emulates PHP's getallheaders() function.
   */
  static function getAllHeaders() {
    if (function_exists('getallheaders')) {
      return getallheaders();
    }

    // emulate get all headers
    // http://www.php.net/manual/en/function.getallheaders.php#66335
    $headers = array();
    foreach ($_SERVER as $name => $value) {
      if (substr($name, 0, 5) == 'HTTP_') {
        $headers[str_replace(' ',
          '-',
          ucwords(strtolower(str_replace('_',
                ' ',
                substr($name, 5)
              )
            ))
        )] = $value;
      }
    }
    return $headers;
  }

  /**
   */
  static function getRequestHeaders() {
    if (function_exists('apache_request_headers')) {
      return apache_request_headers();
    }
    else {
      return $_SERVER;
    }
  }

  /**
   * Determine whether this is an SSL request.
   *
   * Note that we inline this function in install/civicrm.php, so if you change
   * this function, please go and change the code in the install script as well.
   */
  static function isSSL( ) {
    return
      (isset($_SERVER['HTTPS']) &&
        !empty($_SERVER['HTTPS']) &&
        strtolower($_SERVER['HTTPS']) != 'off') ? TRUE : FALSE;
  }

  /**
   */
  static function redirectToSSL($abort = FALSE) {
    $config = CRM_Core_Config::singleton();
    $req_headers = self::getRequestHeaders();
    if (CRM_Core_BAO_Setting::getItem(CRM_Core_BAO_Setting::SYSTEM_PREFERENCES_NAME, 'enableSSL') &&
      !self::isSSL() &&
      strtolower(CRM_Utils_Array::value('X_FORWARDED_PROTO', $req_headers)) != 'https'
    ) {
      // ensure that SSL is enabled on a civicrm url (for cookie reasons etc)
      $url = "https://{$_SERVER['HTTP_HOST']}{$_SERVER['REQUEST_URI']}";
      if (!self::checkURL($url, TRUE)) {
        if ($abort) {
          CRM_Core_Error::fatal('HTTPS is not set up on this machine');
        }
        else {
      CRM_Core_Session::setStatus(ts('HTTPS is not set up on this machine'), ts('Warning'), 'alert');
          // admin should be the only one following this
          // since we dont want the user stuck in a bad place
          return;
        }
      }
      CRM_Utils_System::redirect($url);
    }
  }

  /*
   * Get logged in user's IP address.
   *
   * Get IP address from HTTP REMOTE_ADDR header. If the CMS is Drupal then use
   * the Drupal function as this also handles reverse proxies (based on proper
   * configuration in settings.php)
   *
   * @param bool $strictIPV4
   *   (optional) Whether to return only IPv4 addresses.
   *
   * @return string
   *   IP address of logged in user.
   */
  /**
   * @param bool $strictIPV4
   *
   * @return mixed|string
   */
  static function ipAddress($strictIPV4 = TRUE) {
    $address = CRM_Utils_Array::value('REMOTE_ADDR', $_SERVER);

    $config = CRM_Core_Config::singleton();
    if ($config->userSystem->is_drupal && function_exists('ip_address')) {
      //drupal function handles the server being behind a proxy securely. We still have legacy ipn methods
      // that reach this point without bootstrapping hence the check that the fn exists
        $address = ip_address();
    }

    // hack for safari
    if ($address == '::1') {
      $address = '127.0.0.1';
    }

    // when we need to have strictly IPV4 ip address
    // convert ipV6 to ipV4
    if ($strictIPV4) {
      // this converts 'IPV4 mapped IPV6 address' to IPV4
      if (filter_var($address, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) && strstr($address, '::ffff:')) {
        $address = ltrim($address, '::ffff:');
      }
    }

    return $address;
  }

  /**
   * Get the referring / previous page URL.
   *
   * @return string
   *   The previous page URL
   * @access public
   */
  static function refererPath() {
    return CRM_Utils_Array::value('HTTP_REFERER', $_SERVER);
  }

  /**
   * Get the documentation base URL.
   *
   * @return string
   *   Base URL of the CRM documentation.
   * @access public
   */
  static function getDocBaseURL() {
    // FIXME: move this to configuration at some stage
    return 'http://book.civicrm.org/';
  }

  /**
   * Returns wiki (alternate) documentation URL base.
   *
   * @return string documentation url
   * @access public
   */
  static function getWikiBaseURL() {
    // FIXME: move this to configuration at some stage
    return 'http://wiki.civicrm.org/confluence/display/CRMDOC/';
  }

  /**
   * Returns URL or link to documentation page, based on provided parameters.
   *
   * For use in PHP code.
   * WARNING: Always returns URL, if ts function is not defined ($URLonly has
   * no effect).
   *
   * @param string $page
   *   Title of documentation wiki page.
   * @param boolean $URLonly
   *   (optional) Whether to return URL only or full HTML link (default).
   * @param string $text
   *   (optional) Text of HTML link (no effect if $URLonly = false).
   * @param string $title
   *   (optional) Tooltip text for HTML link (no effect if $URLonly = false)
   * @param string $style
   *   (optional) Style attribute value for HTML link (no effect if $URLonly = false)
   *
   * @param null $resource
   *
   * @return string
   *   URL or link to documentation page, based on provided parameters.
   * @access public
   */
  static function docURL2($page, $URLonly = FALSE, $text = NULL, $title = NULL, $style = NULL, $resource = NULL) {
    // if ts function doesn't exist, it means that CiviCRM hasn't been fully initialised yet -
    // return just the URL, no matter what other parameters are defined
    if (!function_exists('ts')) {
      if ($resource == 'wiki') {
          $docBaseURL = self::getWikiBaseURL();
      } else {
        $docBaseURL = self::getDocBaseURL();
      }
      return $docBaseURL . str_replace(' ', '+', $page);
    }
    else {
      $params = array(
        'page' => $page,
        'URLonly' => $URLonly,
        'text' => $text,
        'title' => $title,
        'style' => $style,
        'resource' => $resource,
      );
      return self::docURL($params);
    }
  }

  /**
   * Returns URL or link to documentation page, based on provided parameters.
   *
   * For use in templates code.
   *
   * @param array $params
   *   An array of parameters (see CRM_Utils_System::docURL2 method for names)
   *
   * @return string
   *   URL or link to documentation page, based on provided parameters.
   * @access public
   */
  static function docURL($params) {

    if (!isset($params['page'])) {
      return;
    }

    if (CRM_Utils_Array::value('resource', $params) == 'wiki') {
      $docBaseURL = self::getWikiBaseURL();
    } else {
      $docBaseURL = self::getDocBaseURL();
    }

    if (!isset($params['title']) or $params['title'] === NULL) {
      $params['title'] = ts('Opens documentation in a new window.');
    }

    if (!isset($params['text']) or $params['text'] === NULL) {
      $params['text'] = ts('(learn more...)');
    }

    if (!isset($params['style']) || $params['style'] === NULL) {
      $style = '';
    }
    else {
      $style = "style=\"{$params['style']}\"";
    }

    $link = $docBaseURL . str_replace(' ', '+', $params['page']);

    if (isset($params['URLonly']) && $params['URLonly'] == TRUE) {
      return $link;
    }
    else {
      return "<a href=\"{$link}\" $style target=\"_blank\" class=\"crm-doc-link no-popup\" title=\"{$params['title']}\">{$params['text']}</a>";
    }
  }

  /**
   * Get the locale set in the hosting CMS
   *
   * @return string
   *   The used locale or null for none.
   */
  static function getUFLocale() {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->getUFLocale();
  }

  /**
   * Execute external or internal URLs and return server response.
   *
   * @param string $url
   *   Request URL.
   * @param bool $addCookie
   *   Whether to provide a cookie. Should be true to access internal URLs.
   *
   * @return string
   *   Response from URL.
   */
  static function getServerResponse($url, $addCookie = TRUE) {
    CRM_Core_TemporaryErrorScope::ignoreException();
    require_once 'HTTP/Request.php';
    $request = new HTTP_Request($url);

    if ($addCookie) {
      foreach ($_COOKIE as $name => $value) {
        $request->addCookie($name, $value);
      }
    }

    if (isset($_SERVER['AUTH_TYPE'])) {
      $request->setBasicAuth($_SERVER['PHP_AUTH_USER'], $_SERVER['PHP_AUTH_PW']);
    }

    $config = CRM_Core_Config::singleton();
    if ($config->userFramework == 'WordPress') {
      session_write_close();
    }

    $request->sendRequest();
    $response = $request->getResponseBody();

    return $response;
  }

  /**
   */
  static function isDBVersionValid(&$errorMessage) {
    $dbVersion = CRM_Core_BAO_Domain::version();

    if (!$dbVersion) {
      // if db.ver missing
      $errorMessage = ts('Version information found to be missing in database. You will need to determine the correct version corresponding to your current database state.');
      return FALSE;
    }
    elseif (!CRM_Utils_System::isVersionFormatValid($dbVersion)) {
      $errorMessage = ts('Database is marked with invalid version format. You may want to investigate this before you proceed further.');
      return FALSE;
    }
    elseif (stripos($dbVersion, 'upgrade')) {
      // if db.ver indicates a partially upgraded db
      $upgradeUrl = CRM_Utils_System::url("civicrm/upgrade", "reset=1");
      $errorMessage = ts('Database check failed - the database looks to have been partially upgraded. You may want to reload the database with the backup and try the <a href=\'%1\'>upgrade process</a> again.', array(1 => $upgradeUrl));
      return FALSE;
    }
    else {
      $codeVersion = CRM_Utils_System::version();

      // if db.ver < code.ver, time to upgrade
      if (version_compare($dbVersion, $codeVersion) < 0) {
        $upgradeUrl = CRM_Utils_System::url("civicrm/upgrade", "reset=1");
        $errorMessage = ts('New codebase version detected. You might want to visit <a href=\'%1\'>upgrade screen</a> to upgrade the database.', array(1 => $upgradeUrl));
        return FALSE;
      }

      // if db.ver > code.ver, sth really wrong
      if (version_compare($dbVersion, $codeVersion) > 0) {
        $errorMessage = '<p>' . ts('Your database is marked with an unexpected version number: %1. The v%2 codebase may not be compatible with your database state. You will need to determine the correct version corresponding to your current database state. You may want to revert to the codebase you were using until you resolve this problem.',
          array(1 => $dbVersion, 2 => $codeVersion)
        ) . '</p>';
        $errorMessage .= "<p>" . ts('OR if this is a manual install from git, you might want to fix civicrm-version.php file.') . "</p>";
        return FALSE;
      }
    }
    // FIXME: there should be another check to make sure version is in valid format - X.Y.alpha_num

    return TRUE;
  }

  /**
   * Exit with provided exit code.
   *
   * @param int $status
   *   (optional) Code with which to exit.
   */
  static function civiExit($status = 0) {
    // move things to CiviCRM cache as needed
    CRM_Core_Session::storeSessionObjects();

    exit($status);
  }

  /**
   * Reset the various system caches and some important static variables.
   */
  static function flushCache( ) {
    // flush out all cache entries so we can reload new data
    // a bit aggressive, but livable for now
    $cache = CRM_Utils_Cache::singleton();
    $cache->flush();

    // also reset the various static memory caches

    // reset the memory or array cache
    CRM_Core_BAO_Cache::deleteGroup('contact fields', NULL, FALSE);

    // reset ACL cache
    CRM_ACL_BAO_Cache::resetCache();

    // reset various static arrays used here
    CRM_Contact_BAO_Contact::$_importableFields =
      CRM_Contact_BAO_Contact::$_exportableFields =
      CRM_Contribute_BAO_Contribution::$_importableFields =
      CRM_Contribute_BAO_Contribution::$_exportableFields =
      CRM_Pledge_BAO_Pledge::$_exportableFields =
      CRM_Contribute_BAO_Query::$_contributionFields =
      CRM_Core_BAO_CustomField::$_importFields =
      CRM_Core_BAO_Cache::$_cache =
      CRM_Core_DAO::$_dbColumnValueCache = NULL;

    CRM_Core_OptionGroup::flushAll();
    CRM_Utils_PseudoConstant::flushAll();
  }

  /**
   * Load CMS bootstrap.
   *
   * @param array $params
   *   Array with uid name and pass
   * @param bool $loadUser
   *   Boolean load user or not.
   * @param bool $throwError
   * @param $realPath
   */
  static function loadBootStrap($params = array(
    ), $loadUser = TRUE, $throwError = TRUE, $realPath = NULL) {
    if (!is_array($params)) {
      $params = array();
    }
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->loadBootStrap($params, $loadUser, $throwError, $realPath);
  }

  /**
   * Check if user is logged in.
   *
   * @return bool
   */
  public static function isUserLoggedIn() {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->isUserLoggedIn();
  }

  /**
   * Get current logged in user id.
   *
   * @return int
   *   ufId, currently logged in user uf id.
   */
  public static function getLoggedInUfID() {
    $config = CRM_Core_Config::singleton();
    return $config->userSystem->getLoggedInUfID();
  }

  /**
   */
  static function baseCMSURL() {
    static $_baseURL = NULL;
    if (!$_baseURL) {
      $config = CRM_Core_Config::singleton();
      $_baseURL = $userFrameworkBaseURL = $config->userFrameworkBaseURL;

      if ($config->userFramework == 'Joomla') {
        // gross hack
        // we need to remove the administrator/ from the end
        $_baseURL = str_replace("/administrator/", "/", $userFrameworkBaseURL);
      }
      else {
        // Drupal setting
        global $civicrm_root;
        if (strpos($civicrm_root,
            DIRECTORY_SEPARATOR . 'sites' .
            DIRECTORY_SEPARATOR . 'all' .
            DIRECTORY_SEPARATOR . 'modules'
          ) === FALSE) {
          $startPos = strpos($civicrm_root,
            DIRECTORY_SEPARATOR . 'sites' . DIRECTORY_SEPARATOR
          );
          $endPos = strpos($civicrm_root,
            DIRECTORY_SEPARATOR . 'modules' . DIRECTORY_SEPARATOR
          );
          if ($startPos && $endPos) {
            // if component is in sites/SITENAME/modules
            $siteName = substr($civicrm_root,
              $startPos + 7,
              $endPos - $startPos - 7
            );

            $_baseURL = $userFrameworkBaseURL . "sites/$siteName/";
          }
        }
      }
    }
    return $_baseURL;
  }

  /**
   * Given a URL, return a relative URL if possible.
   *
   * @param string $url
   * @return string
   */
  static function relativeURL($url) {
    // check if url is relative, if so return immediately
    if (substr($url, 0, 4) != 'http') {
      return $url;
    }

    // make everything relative from the baseFilePath
    $baseURL = self::baseCMSURL();

    // check if baseURL is a substr of $url, if so
    // return rest of string
    if (substr($url, 0, strlen($baseURL)) == $baseURL) {
      return substr($url, strlen($baseURL));
    }

    // return the original value
    return $url;
  }

  /**
   * Produce an absolute URL from a possibly-relative URL.
   *
   * @param string $url
   * @param bool $removeLanguagePart
   *
   * @internal param bool $remoteLanguagePart
   * @return string
   */
  static function absoluteURL($url, $removeLanguagePart = FALSE) {
    // check if url is already absolute, if so return immediately
    if (substr($url, 0, 4) == 'http') {
      return $url;
    }

    // make everything absolute from the baseFileURL
    $baseURL = self::baseCMSURL();

    //CRM-7622: drop the language from the URL if requested (and it’s there)
    $config = CRM_Core_Config::singleton();
    if ($removeLanguagePart) {
      $baseURL = self::languageNegotiationURL($baseURL, FALSE, TRUE);
    }

    return $baseURL . $url;
  }

  /**
   * Function to clean url, replaces first '&' with '?'
   *
   * @param string $url
   *
   * @return string $url, clean url
   */
  static function cleanUrl($url) {
    if (!$url) {
      return NULL;
    }

    if ($pos = strpos($url, '&')) {
      $url = substr_replace($url, '?', $pos, 1);
    }

    return $url;
  }

  /**
   * Format the url as per language Negotiation.
   *
   * @param string $url
   *
   * @param bool $addLanguagePart
   * @param bool $removeLanguagePart
   *
   * @return string $url, formatted url.
   */
  static function languageNegotiationURL($url,
    $addLanguagePart = TRUE,
    $removeLanguagePart = FALSE
  ) {
    $config = &CRM_Core_Config::singleton();
    return $config->userSystem->languageNegotiationURL($url, $addLanguagePart, $removeLanguagePart);
  }

  /**
   * Append the contents of an 'extra' smarty template file if it is present in
   * the custom template directory. This does not work if there are
   * multiple custom template directories
   *
   * @param string $fileName
   *   The name of the tpl file that we are processing.
   * @param string $content
   *   The current content string. May be modified by this function.
   * @param string $overideFileName
   *   (optional) Sent by contribution/event reg/profile pages which uses a id
   *   specific extra file name if present.
   */
  static function appendTPLFile($fileName,
    &$content,
    $overideFileName = NULL
  ) {
    $template = CRM_Core_Smarty::singleton();
    if ($overideFileName) {
      $additionalTPLFile = $overideFileName;
    }
    else {
      $additionalTPLFile = str_replace('.tpl', '.extra.tpl', $fileName);
    }

    if ($template->template_exists($additionalTPLFile)) {
      $content .= $template->fetch($additionalTPLFile);
    }
  }

  /**
   * Get a list of all files that are found within the directories
   * that are the result of appending the provided relative path to
   * each component of the PHP include path.
   *
   * @author Ken Zalewski
   *
   * @param string $relpath
   *   A relative path, typically pointing to a directory with multiple class
   *   files.
   *
   * @return array
   *   An array of files that exist in one or more of the directories that are
   *   referenced by the relative path when appended to each element of the PHP
   *   include path.
   * @access public
   */
  static function listIncludeFiles($relpath) {
    $file_list = array();
    $inc_dirs = explode(PATH_SEPARATOR, get_include_path());
    foreach ($inc_dirs as $inc_dir) {
      $target_dir = $inc_dir . DIRECTORY_SEPARATOR . $relpath;
      if (is_dir($target_dir)) {
        $cur_list = scandir($target_dir);
        foreach ($cur_list as $fname) {
          if ($fname != '.' && $fname != '..') {
            $file_list[$fname] = $fname;
          }
        }
      }
    }
    return $file_list;
  }
  // listIncludeFiles()

  /**
   * Get a list of all "plugins" (PHP classes that implement a piece of
   * functionality using a well-defined interface) that are found in a
   * particular CiviCRM directory (both custom and core are searched).
   *
   * @author Ken Zalewski
   *
   * @param string $relpath
   *   A relative path referencing a directory that contains one or more
   *   plugins.
   * @param string $fext
   *   (optional) Only files with this extension will be considered to be
   *   plugins.
   * @param array $skipList
   *   (optional) List of files to skip.
   *
   * @return array
   *   List of plugins, where the plugin name is both the key and the value of
   *   each element.
   * @access public
   */
  static function getPluginList($relpath, $fext = '.php', $skipList = array(
    )) {
    $fext_len  = strlen($fext);
    $plugins   = array();
    $inc_files = CRM_Utils_System::listIncludeFiles($relpath);
    foreach ($inc_files as $inc_file) {
      if (substr($inc_file, 0 - $fext_len) == $fext) {
        $plugin_name = substr($inc_file, 0, 0 - $fext_len);
        if (!in_array($plugin_name, $skipList)) {
          $plugins[$plugin_name] = $plugin_name;
        }
      }
    }
    return $plugins;
  }
  // getPluginList()

  /**
   *
   */
  static function executeScheduledJobs() {
    $facility = new CRM_Core_JobManager();
    $facility->execute(FALSE);

    $redirectUrl = self::url('civicrm/admin/job', 'reset=1');

    CRM_Core_Session::setStatus(
      ts('Scheduled jobs have been executed according to individual timing settings. Please check log for messages.'),
      ts('Complete'), 'success');

    CRM_Utils_System::redirect($redirectUrl);
  }

  /**
   * Evaluate any tokens in a URL.
   *
   * @param string|FALSE $url
   * @return string|FALSE
   */
  public static function evalUrl($url) {
    if ($url === FALSE) {
      return FALSE;
    }
    else {
      $config = CRM_Core_Config::singleton();
      $vars = array(
        '{ver}' => CRM_Utils_System::version(),
        '{uf}' => $config->userFramework,
        '{php}' => phpversion(),
        '{sid}' => md5('sid_' . (defined('CIVICRM_SITE_KEY') ? CIVICRM_SITE_KEY : '') . '_' . $config->userFrameworkBaseURL),
        '{baseUrl}' => $config->userFrameworkBaseURL,
        '{lang}' => $config->lcMessages,
        '{co}' => $config->defaultContactCountry,
      );
      foreach (array_keys($vars) as $k) {
        $vars[$k] = urlencode($vars[$k]);
      }
      return strtr($url, $vars);
    }
  }


  /**
   * Determine whether this is a developmental system.
   *
   * @return bool
   */
  static function isDevelopment() {
    static $cache = NULL;
    if ($cache === NULL) {
      global $civicrm_root;
      $cache = file_exists("{$civicrm_root}/.svn") || file_exists("{$civicrm_root}/.git");
    }
    return $cache;
  }

  /**
   * @return bool
   */
  static function isInUpgradeMode() {
    $args = explode('/', $_GET['q']);
    $upgradeInProcess = CRM_Core_Session::singleton()->get('isUpgradePending');
    if ((isset($args[1]) && $args[1] == 'upgrade') || $upgradeInProcess) {
      return TRUE;
    }
    else {
      return FALSE;
    }
  }

  /**
   * Determine the standard URL for viewing or editing the specified link
   *
   * This function delegates the decision-making to (a) the hook system and
   * (b) the BAO system.
   *
   * @param array $crudLinkSpec with keys:
   *  - action: int, CRM_Core_Action::UPDATE or CRM_Core_Action::VIEW [default: VIEW]
   *  - entity_table: string, eg "civicrm_contact"
   *  - entity_id: int
   * @return array|NULL NULL if unavailable, or an array. array has keys:
   *  - path: string
   *  - query: array
   *  - title: string
   *  - url: string
   */
  static function createDefaultCrudLink($crudLinkSpec) {
    $crudLinkSpec['action'] = CRM_Utils_Array::value('action', $crudLinkSpec, CRM_Core_Action::VIEW);
    $daoClass = CRM_Core_DAO_AllCoreTables::getClassForTable($crudLinkSpec['entity_table']);
    if (!$daoClass) {
      return NULL;
    }

    $baoClass = str_replace('_DAO_', '_BAO_', $daoClass);
    if (!class_exists($baoClass)) {
      return NULL;
    }

    $bao = new $baoClass();
    $bao->id = $crudLinkSpec['entity_id'];
    if (!$bao->find(TRUE)) {
      return NULL;
    }

    $link = array();
    CRM_Utils_Hook::crudLink($crudLinkSpec, $bao, $link);
    if (empty($link) && is_callable(array($bao, 'createDefaultCrudLink'))) {
      $link = $bao->createDefaultCrudLink($crudLinkSpec);
    }

    if (!empty($link)) {
      if (!isset($link['url'])) {
        $link['url'] = self::url($link['path'], $link['query'], TRUE, NULL, FALSE);
      }
      return $link;
    }

    return NULL;
  }
}