[project/devel.git] / devel.module

<?php
// $Id$

// This module holds functions useful for Drupal development.
// Please contribute!

// Suggested profiling and stacktrace library from http://www.xdebug.org/index.php

define('DEVEL_QUERY_SORT_BY_SOURCE', 0);
define('DEVEL_QUERY_SORT_BY_DURATION', 1);

define('DEVEL_ERROR_HANDLER_NONE', 0);
define('DEVEL_ERROR_HANDLER_STANDARD', 1);
define('DEVEL_ERROR_HANDLER_BACKTRACE', 2);

define('DEVEL_MIN_TEXTAREA', 50);

/**
 * Implementation of hook_help().
 */
function devel_help($section) {
  switch ($section) {
    case 'devel/reference':
      return '<p>'. t('This is a list of defined user functions that generated this current request lifecycle. Click on a function name to view its documention.') .'</p>';
    case 'devel/session':
      return '<p>'. t('Here are the contents of your <code>$_SESSION</code> variable.') .'</p>';
    case 'devel/variable':
      $api = variable_get('devel_api_url', 'api.drupal.org');
      return '<p>'. t('This is a list of the variables and their values currently stored in variables table and the <code>$conf</code> array of your settings.php file. These variables are usually accessed with <a href="@variable-get-doc">variable_get()</a> and <a href="@variable-set-doc">variable_set()</a>. Variables that are too long can slow down your pages.', array('@variable-get-doc' => "http://$api/api/HEAD/function/variable_get", '@variable-set-doc' => "http://$api/api/HEAD/function/variable_set")) .'</p>';
    case 'devel/reinstall':
      return t('Warning - will delete your module tables and variables.');
  }
}

/**
 * Implementationation of hook_menu().
 */
function devel_menu() {
  $items = array();
  // Note: we can't dynamically append destination to querystring. Do so at theme layer. Fix in D7?
  $items['devel/cache/clear'] = array(
    'title' => 'Empty cache',
    'page callback' => 'devel_cache_clear',
    'description' => 'Clear the CSS cache and all database cache tables which store page, node, theme and variable caches.',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );

  $items['devel/reference'] = array(
    'title' => 'Function reference',
    'description' => 'View a list of currently defined user functions with documentation links.',
    'page callback' => 'devel_function_reference',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/reinstall'] = array(
    'title' => 'Reinstall modules',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('devel_reinstall'),
    'description' => 'Run hook_uninstall() and then hook_install() for a given module.',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/source'] = array(
    'title' => 'Display the PHP code of any file in your Drupal installation',
    'page callback' => 'devel_display_source',
    'access arguments' => array('display source code'),
    'type' => MENU_CALLBACK,
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/menu/reset'] = array(
    'title' => 'Rebuild menus',
    'description' => 'Rebuild menu based on hook_menu() and revert any custom changes. All menu items return to their default settings.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('devel_menu_rebuild'),
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/menu/item'] = array(
    'title' => 'Menu item',
    'description' => 'Details about a given menu item.',
    'page callback' => 'devel_menu_item',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/variable'] = array(
    'title' => 'Variable editor',
    'description' => 'Edit and delete site variables.',
    'page callback' => 'devel_variable_page',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  // we don't want the abbreviated version provided by status report
  $items['devel/phpinfo'] = array(
    'title' => 'PHPinfo()',
    'description' => 'View your server\'s PHP configuration',
    'page callback' => 'devel_phpinfo',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/php'] = array(
    'title' => 'Execute PHP Code',
    'description' => 'Execute some PHP code',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('devel_execute_form'),
    'access arguments' => array('execute php code'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/theme/registry'] = array(
    'title' => 'Theme registry',
    'description' => 'View a list of available theme functions across the whole site.',
    'page callback' => 'devel_theme_registry',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/field/info'] = array(
    'title' => 'Field info',
    'description' => 'View fields information across the whole site.',
    'page callback' => 'devel_field_info_page',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/elements'] = array(
    'title' => 'Hook_elements()',
    'description' => 'View the active form/render elements for this site.',
    'page callback' => 'devel_elements_page',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/variable/edit/%'] = array(
    'title' => 'Variable editor',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('devel_variable_edit', 3),
    'access arguments' => array('access devel information'),
    'type' => MENU_CALLBACK,
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/session'] = array(
    'title' => 'Session viewer',
    'description' => 'List the contents of $_SESSION.',
    'page callback' => 'devel_session',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/switch'] = array(
    'title' => 'Switch user',
    'page callback' => 'devel_switch_user',
    'access arguments' => array('switch users'),
    'type' => MENU_CALLBACK,
    'file' => 'devel.pages.inc',
    'menu_name' => 'devel',
  );
  $items['devel/explain'] = array(
    'title' => 'Explain query',
    'page callback' => 'devel_querylog_explain',
    'description' => 'Run an EXPLAIN on a given query. Used by query log',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_CALLBACK
  );
  $items['devel/arguments'] = array(
    'title' => 'Arguments query',
    'page callback' => 'devel_querylog_arguments',
    'description' => 'Return a giben query, with arguments instead of placeholders. Used by query log',
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_CALLBACK
  );
  $items['devel/run-cron'] = array(
    'title' => 'Run cron',
    'page callback' => 'system_run_cron',
    'access arguments' => array('administer site configuration'),
    'file' => 'system.admin.inc',
    'file path' => drupal_get_path('module', 'system'),
    'menu_name' => 'devel',
  );

  // Duplicate path in 2 different menus. See http://drupal.org/node/601788.
  $items['devel/settings'] = array(
    'title' => 'Devel settings',
    'description' =>  'Helper functions, pages, and blocks to assist Drupal developers. The devel blocks can be managed via the <a href="' . url('admin/structure/block') . '">block administration</a> page.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('devel_admin_settings'),
    'access arguments' => array('administer site configuration'),
    'file' => 'devel.admin.inc',
    'menu_name' => 'devel',
  );
  $items['admin/config/development/devel'] = array(
    'title' => 'Devel settings',
    'description' =>  'Helper functions, pages, and blocks to assist Drupal developers. The devel blocks can be managed via the <a href="' . url('admin/structure/block') . '">block administration</a> page.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('devel_admin_settings'),
    'file' => 'devel.admin.inc',
    'access arguments' => array('administer site configuration'),
  );

  $items['node/%node/devel'] = array(
    'title' => 'Devel',
    'page callback' => 'devel_load_object',
    'page arguments' => array(1, 'node'),
    'access arguments' => array('access devel information'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'devel.pages.inc',
    'weight' => 100,
  );
  $items['node/%node/devel/load'] = array(
    'title' => 'Load',
    'page callback' => 'devel_load_object',
    'page arguments' => array(1, 'node'),
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['node/%node/devel/render'] = array(
    'title' => 'Render',
    'page callback' => 'devel_render_object',
    'page arguments' => array('node', 1),
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_LOCAL_TASK,
    'weight' => 100,
  );
  $items['comment/%comment/devel'] = array(
    'title' => 'Devel',
    'page callback' => 'devel_load_object',
    'page arguments' => array(1, 'comment'),
    'access arguments' => array('access devel information'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'devel.pages.inc',
    'weight' => 100,
  );
  $items['comment/%comment/devel/load'] = array(
    'title' => 'Load',
    'page callback' => 'devel_load_object',
    'page arguments' => array(1, 'comment'),
    'access arguments' => array('access devel information'),
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'file' => 'devel.pages.inc',
  );
  $items['comment/%comment/devel/render'] = array(
    'title' => 'Render',
    'page callback' => 'devel_render_object',
    'page arguments' => array('comment', 1),
    'access arguments' => array('access devel information'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'devel.pages.inc',
    'weight' => 100,
  );
  $items['user/%user/devel'] = array(
    'title' => 'Devel',
    'page callback' => 'devel_load_object',
    'page arguments' => array(1, 'user'),
    'access arguments' => array('access devel information'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'devel.pages.inc',
    'weight' => 100,
  );
  $items['user/%user/devel/load'] = array(
    'title' => 'Load',
    'page callback' => 'devel_load_object',
    'page arguments' => array(1, 'user'),
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['user/%user/devel/render'] = array(
    'title' => 'Render',
    'page callback' => 'devel_render_object',
    'page arguments' => array('user', 1),
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_LOCAL_TASK,
    'weight' => 100,
  );
  $items['taxonomy/term/%taxonomy_term/devel'] = array(
    'title' => 'Devel',
    'page callback' => 'devel_load_object',
    'page arguments' => array(2, 'term'),
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_LOCAL_TASK,
    'weight' => 100,
  );
  $items['taxonomy/term/%taxonomy_term/devel/load'] = array(
    'title' => 'Load',
    'page callback' => 'devel_load_object',
    'page arguments' => array(2, 'term'),
    'access arguments' => array('access devel information'),
    'file' => 'devel.pages.inc',
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['taxonomy/term/%taxonomy_term/devel/render'] = array(
    'title' => 'Render',
    'page callback' => 'devel_render_term',
    'page arguments' => array(2),
    'access arguments' => array('access devel information'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'devel.pages.inc',
    'weight' => 100,
  );

  return $items;
}

function devel_menu_need_destination() {
  return array('devel/cache/clear', 'devel/reinstall', 'devel/menu/reset', 'devel/variable', 'admin/reports/status/run-cron');
}

/**
 * An implementation of hook_menu_link_alter(). Flag this link as needing alter at display time.
 * This is more robust that setting alter in hook_menu().
 * @see devel_translated_menu_link_alter().
 *
 **/
function devel_menu_link_alter(&$item) {
  if (in_array($item['link_path'], devel_menu_need_destination()) || $item['link_path'] == 'devel/menu/item') {
    $item['options']['alter'] = TRUE;
  }
}

/**
 * An implementation of hook_translated_menu_item_alter(). Append dynamic
 * querystring 'destination' to several of our own menu items.
 *
 **/
function devel_translated_menu_link_alter(&$item) {
  if (in_array($item['href'], devel_menu_need_destination())) {
    $item['localized_options']['query'] = drupal_get_destination();
  }
  elseif ($item['href'] == 'devel/menu/item') {
    $item['localized_options']['query'] = array('path' => $_GET['q']);
  }
}

/**
 * Implementation of hook_theme()
 */
function devel_theme() {
  return array(
    'devel_querylog' => array(
      'variables' => array('header' => array(), 'rows' => array()),
    ),
    'devel_querylog_row' => array(
      'variables' => array('row' => array()),
    ),
  );
}

/**
 * Implementation of hook_init().
 */
function devel_init() {
  if (!devel_silent()) {
    if (user_access('access devel information')) {
      devel_set_handler(variable_get('devel_error_handler', DEVEL_ERROR_HANDLER_STANDARD));
      // We want to include the class early so that anyone may call krumo() as needed. See http://krumo.sourceforge.net/
      has_krumo();

      // Initialize XHProf.
      if (extension_loaded('xhprof')) {
        $path = variable_get('devel_xhprof_directory', '');
        if ($path) {
          include_once $path . '/xhprof_lib/utils/xhprof_lib.php';
          include_once $path . '/xhprof_lib/utils/xhprof_runs.php';
          if (variable_get('devel_xhprof_enabled', FALSE)) {
            // @todo: consider a variable per-flag instead.
            xhprof_enable(XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY);
          }
        }
      }

      // See http://www.firephp.org/.
      // Support Libraries API - http://drupal.org/project/libraries
      if (module_exists('libraries')) {
        $path = libraries_get_path('FirePHPCore') . '/lib/FirePHPCore/';
      }
      else {
        $path = './'. drupal_get_path('module', 'devel') .'/FirePHPCore/lib/FirePHPCore/';
      }
      if (file_exists($path .'fb.php')) {
        include_once $path .'fb.php';
        include_once $path .'FirePHP.class.php';
      }
      // Add CSS for query log if should be displayed.
      if (variable_get('devel_query_display', 0)) {
        drupal_add_css(drupal_get_path('module', 'devel') .'/devel.css');
        drupal_add_js(drupal_get_path('module', 'devel'). '/devel.js');
      }
    }
  }
  if (variable_get('devel_rebuild_theme_registry', FALSE)) {
    drupal_theme_rebuild();
    if (flood_is_allowed('devel_rebuild_registry_warning', 1)) {
      flood_register_event('devel_rebuild_registry_warning');
      if (!devel_silent() && user_access('access devel information')) {
        drupal_set_message(t('The theme registry is being rebuilt on every request. Remember to <a href="!url">turn off</a> this feature on production websites.', array("!url" => url('admin/config/development/devel'))));
      }
    }
  }
}

function devel_set_message($msg, $type = NULL) {
  $function  = function_exists('drush_log') ? 'drush_log' : 'drupal_set_message';
  $function($msg, $type);
}

// Return boolean. No need for cache here.
function has_krumo() {
  // see README.txt or just download from http://krumo.sourceforge.net/
  @include_once DRUPAL_ROOT . '/' . drupal_get_path('module', 'devel') .'/krumo/class.krumo.php';
  return function_exists('krumo') && !drupal_is_cli();
}

/**
 * Decide whether or not to print a debug variable using krumo().
 *
 * @param $input
 * @return boolean
 */
function merits_krumo($input) {
  return (is_object($input) || is_array($input)) && has_krumo() && variable_get('devel_krumo_skin', '') != 'disabled';
}

/**
 * Calls the http://www.firephp.org/ fb() function if it is found.
 *
 * @return void
 */
function dfb() {
  if (function_exists('fb') && user_access('access devel information') && !headers_sent()) {
    $args = func_get_args();
    call_user_func_array('fb', $args);
  }
}

/**
 * Calls dfb() to output a backtrace.
 */
function dfbt($label) {
  dfb($label, FirePHP::TRACE);
}

/**
 * Implements hook_watchdog().
 */
function devel_watchdog(array $log_entry) {
  if (class_exists('FirePHP')) {
    switch ($log_entry['severity']) {
      case WATCHDOG_EMERGENCY:
      case WATCHDOG_ALERT:
      case WATCHDOG_CRITICAL:
      case WATCHDOG_ERROR:
        $type = FirePHP::ERROR;
        break;
      case WATCHDOG_WARNING:
        $type = FirePHP::WARN;
        break;
      case WATCHDOG_NOTICE:
      case WATCHDOG_INFO:
        $type = FirePHP::INFO;
        break;
      case WATCHDOG_DEBUG:
      DEFAULT:
        $type = FirePHP::LOG;
    }
  }
  else {
    $type = 'watchdog';
  }
  $function = function_exists('decode_entities') ? 'decode_entities' : 'html_entity_decode';
  $watchdog = array(
    'type' => $log_entry['type'],
    'message' => $function(strtr($log_entry['message'], (array)$log_entry['variables'])),
  );
  if (isset($log_entry['link'])) {
    $watchdog['link'] = $log_entry['link'];
  }
  dfb($watchdog, $type);
}

function devel_set_handler($handler) {
  switch ($handler) {
    case DEVEL_ERROR_HANDLER_STANDARD:
      // do nothing
      break;
    case DEVEL_ERROR_HANDLER_BACKTRACE:
      if (has_krumo()) {
        set_error_handler('backtrace_error_handler');
      }
      break;
    case DEVEL_ERROR_HANDLER_NONE:
      restore_error_handler();
      break;
  }
}

function devel_silent() {
  // isset($_GET['q']) is needed on IIS when calling the front page. q is not set.
  // Don't interfere with private files/images.
  return
    function_exists('drupal_is_cli') && drupal_is_cli() ||
    strpos($_SERVER['HTTP_USER_AGENT'], 'ApacheBench') !== FALSE ||
    !empty($_REQUEST['XDEBUG_PROFILE']) ||
    isset($GLOBALS['devel_shutdown']) ||
    strstr($_SERVER['PHP_SELF'], 'update.php') ||
    (isset($_GET['q']) && (
      in_array($_GET['q'], array( 'admin/content/node-settings/rebuild')) ||
      substr($_GET['q'], 0, strlen('system/files')) == 'system/files' ||
      substr($_GET['q'], 0, strlen('batch')) == 'batch') ||
      substr($_GET['q'], 0, strlen('file/ajax')) == 'file/ajax'
    );
}

/**
 * Implementation of hook_boot(). Runs even for cached pages.
 */
function devel_boot() {
  if (!devel_silent()) {
    devel_start();
  }
}

// Kickoff our tricks. Put here all code which must run for cached pages too. Called from both devel_boot() and devel_init().
function devel_start() {
  if (variable_get('dev_mem', 0)) {
    global $memory_init;
    $memory_init = memory_get_usage();
  }

  if (devel_query_enabled()) {
    @include_once DRUPAL_ROOT . '/includes/database/log.inc';
    Database::startLog('devel');;
  }

  // We need user_access() in the shutdown function. make sure it gets loaded.
  // Also prime the drupal_get_filename() static with user.module's location to
  // avoid a stray query.
  drupal_get_filename('module', 'user', 'modules/user/user.module');
  drupal_load('module', 'user');
  register_shutdown_function('devel_shutdown');
}

function backtrace_error_handler($errno, $message, $filename, $line) {
  // Don't respond to the error if it was suppressed with a '@'
  if (error_reporting() == 0) return;

  if ($errno & (E_ALL ^ E_NOTICE)) {
    // We can't use the PHP E_* constants here as not all versions of PHP have all
    // the constants defined, so for consistency, we just use the numeric equivelant.
    $types = array(
      1 => 'error',
      2 => 'warning',
      4 => 'parse error',
      8 => 'notice',
      16 => 'core error',
      32 => 'core warning',
      64 => 'compile error',
      128 => 'compile warning',
      256 => 'user error',
      512 => 'user warning',
      1024 => 'user notice',
      2048 => 'strict warning',
      4096 => 'recoverable error',
      8192 => 'deprecated',
      16384 => 'user deprecated',
    );
    $entry = $types[$errno] .': '. $message .' in '. $filename .' on line '. $line .'.';

    if (variable_get('error_level', 1) == 1) {
      $backtrace = debug_backtrace();
      foreach ($backtrace as $call) {
        $nicetrace[$call['function']] = $call;
      }
      krumo($nicetrace);
    }

    watchdog('php', '%message in %file on line %line.', array('%error' => $types[$errno], '%message' => $message, '%file' => $filename, '%line' => $line), WATCHDOG_ERROR);
  }
}

/**
 * Implement hook_permission().
 */
function devel_permission() {
  return array(
    'access devel information' => array(
      'description' => t('View developer output like variable printouts, query log, etc.'),
      'title' => t('Access developer information'),
    ),
    'execute php code' => array(
      'title' => t('Execute PHP code'),
      'description' => t('Run arbitrary PHP from a block. Danger!'),
    ),
    'switch users' => array(
      'title' => t('Switch users'),
      'description' => t('Become any user on the site with just a click. Danger!'),
    ),
    'display source code' => array(
      'title' => t('Display source code'),
      'description' => t('View the site\'s php source code. Danger!'),
    ),
  );
}

function devel_block_info() {
  $blocks['execute_php'] = array(
    'info' => t('Execute PHP'),
    'cache' => DRUPAL_NO_CACHE,
  );
  $blocks['switch_user'] = array(
    'info' => t('Switch user'),
    'cache' => DRUPAL_NO_CACHE,
  );
  return $blocks;
}

/**
 * Implementation of hook_block_configure().
 */
function devel_block_configure($delta) {
  if ($delta == 'switch_user') {
    $form['devel_switch_user_list_size'] = array(
      '#type' => 'textfield',
      '#title' => t('Number of users to display in the list'),
      '#default_value' => variable_get('devel_switch_user_list_size', 10),
      '#size' => '3',
      '#maxlength' => '4',
    );
    return $form;
  }
}

function devel_block_save($delta, $edit = array()) {
  if ($delta == 'switch_user') {
    variable_set('devel_switch_user_list_size', $edit['devel_switch_user_list_size']);
  }
}

function devel_block_view($delta) {
  $block = array();
  switch ($delta) {
    case 'switch_user':
      $block = devel_block_switch_user();
      break;

    case 'execute_php':
      if (user_access('execute php code')) {
        $block['subject'] = t('Execute PHP');
        $block['content'] = drupal_get_form('devel_execute_form');
      }
      break;
  }
  return $block;
}

function devel_block_switch_user() {
  $links = devel_switch_user_list();
  if (!empty($links) || user_access('switch users')) {
    $block['subject'] = t('Switch user');
    $build['devel_links'] = array('#theme' => 'links', '#links' => $links);
    $build['devel_form'] = drupal_get_form('devel_switch_user_form');
    $block['content'] = $build;
    return $block;
  }
}

function devel_switch_user_list() {
  $links = array();
  if (user_access('switch users')) {
    $list_size = variable_get('devel_switch_user_list_size', 10);
    $dest = drupal_get_destination();
    // Try to find at least $list_size users that can switch.
    $roles = user_roles(1, 'switch users');
    if (isset($roles[2])) {
      // If authenticated users have this permission, just grab
      // the last $list_size users, since there won't be records in
      // {user_roles} and every user on the system can switch.
      $users = db_query_range("SELECT DISTINCT u.uid, u.name, u.access FROM {users} u WHERE u.uid > 0 ORDER BY u.access DESC", 0, $list_size);
    }
    else {
      $where = array('u.uid = 1');
      if (count($roles)) {
        $where[] = 'r.rid IN ('. implode(',', array_keys($roles)) .')';
      }
      $where_sql = implode(' OR ', $where);
      $users = db_query_range("SELECT DISTINCT u.uid, u.name, u.access FROM {users} u LEFT JOIN {users_roles} r ON u.uid = r.uid WHERE $where_sql ORDER BY u.access DESC", 0, $list_size);
    }
    foreach ($users as $user) {
      $links[$user->uid] = array(
        'title' => drupal_placeholder(array('text' => $user->name)),
        'href' => 'devel/switch/'. $user->name,
        'query' => $dest,
        'attributes' => array('title' => t('This user can switch back.')),
        'html' => TRUE,
      );
    }
    $num_links = count($links);
    if ($num_links < $list_size) {
      // If we don't have enough, add distinct uids until we hit $list_size.
      $users = db_query_range('SELECT uid, name, access FROM {users} WHERE uid > 0 AND uid NOT IN ('. implode(',', array_keys($links)) .') ORDER BY access DESC', 0, $list_size - $num_links);
      foreach ($users as $user) {
        if (count($links) >= $list_size) {
          break;
        }
        $links[$user->uid] = array(
          'title' => $user->name ? $user->name : 'anon',
          'href' => 'devel/switch/'. $user->name,
          'query' => $dest,
          'attributes' => array('title' => t('Caution: this user will be unable switch back.')),
        );
      }
    }
  }
  return $links;
}

function devel_switch_user_form() {
  $form['username'] = array(
    '#type' => 'textfield',
    '#description' => t('Enter username'),
    '#autocomplete_path' => 'user/autocomplete',
    '#maxlength' => USERNAME_MAX_LENGTH,
    '#size' => 16,
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Switch'),
  );
  return $form;

}

function devel_doc_function_form() {
  $version = devel_get_core_version(VERSION);
  $form['function'] = array(
    '#type' => 'textfield',
    '#description' => t('Enter function name for api lookup'),
    '#size' => 16,
    '#maxlength' => 255,
  );
  $form['version'] = array('#type' => 'value', '#value' => $version);
  $form['submit_button'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );
  return $form;
}

function devel_doc_function_form_submit($form, &$form_state) {
  $version = $form_state['values']['version'];
  $function = $form_state['values']['function'];
  $api = variable_get('devel_api_url', 'api.drupal.org');
  $form_state['redirect'] =   "http://$api/api/$version/function/$function";
}

function devel_switch_user_form_validate($form, &$form_state) {
  if (!$account = user_load_by_name($form_state['values']['username'])) {
    form_set_error('username', t('Username not found'));
  }
}

function devel_switch_user_form_submit($form, &$form_state) {
  $form_state['redirect'] = 'devel/switch/'. $form_state['values']['username'];
}

// An implementation of hook_drupal_goto_alter().
function devel_drupal_goto_alter($path, $options, $http_response_code) {
  global $user;

  if (isset($path) && !devel_silent()) {
    // The page we are leaving is a drupal_goto(). Present a redirection page
    // so that the developer can see the intermediate query log.
    // We don't want to load user module here, so keep function_exists() call.
    if (isset($user) && function_exists('user_access') && user_access('access devel information') && variable_get('devel_redirect_page', 0)) {
      $destination = function_exists('url') ? url($path, $options) : $path;
      $output = t_safe('<p>The user is being redirected to <a href="@destination">@destination</a>.</p>', array('@destination' => $destination));
      drupal_deliver_page($output);

      // Don't allow the automatic redirect to happen.
      exit();
    }
    else {
      $GLOBALS['devel_redirecting'] = TRUE;
    }
  }
}

/**
 * See devel_start() which registers this function as a shutdown function.
 */
function devel_shutdown() {
  // Register the real shutdown function so it runs later than other shutdown functions.
  register_shutdown_function('devel_shutdown_real');
}

function devel_page_alter($page) {
  if (variable_get('devel_page_alter', FALSE) && user_access('access devel information')) {
    dpm($page, 'page');
  }
}

// AJAX render reponses sometimers are sent as text/html so we have to catch them here
// and disable our footer stuff.
function devel_ajax_render_alter() {
  $GLOBALS['devel_shutdown'] = FALSE;
}

/**
 * See devel_shutdown() which registers this function as a shutdown function. Displays developer information in the footer.
 */
function devel_shutdown_real() {
  global $user;
  $output = $txt = '';

  // Set $GLOBALS['devel_shutdown'] = FALSE in order to supress the
  // devel footer for a page.  Not necessary if your page outputs any
  // of the Content-type http headers tested below (e.g. text/xml,
  // text/javascript, etc).  This is is advised where applicable.
  if (!isset($GLOBALS['devel_shutdown']) && !isset($GLOBALS['devel_redirecting'])) {
    // Try not to break non html pages.
    if (function_exists('drupal_get_http_header')) {
      $header = drupal_get_http_header('content-type');
      if ($header) {
        $formats = array('xml', 'javascript', 'json', 'plain', 'image', 'application', 'csv', 'x-comma-separated-values');
        foreach ($formats as $format) {
          if (strstr($header, $format)) {
            return;
          }
        }
      }
    }

    if (isset($user) && user_access('access devel information')) {
      $queries = Database::getLog('devel', 'default');
      $output .= devel_shutdown_summary($queries);
      $output .= devel_shutdown_query($queries);
    }

    if ($output) {
      // TODO: gzip this text if we are sending a gzip page. see drupal_page_header().
      // For some reason, this is not actually printing for cached pages even though it gets executed
      // and $output looks good.
      print $output;
    }
  }
}

function devel_shutdown_summary($queries) {
  $sum = 0;
  $output = '';
  list($counts, $query_summary) = devel_query_summary($queries);

  $output .= '<div class="dev-query">';

  if (variable_get('devel_query_display', FALSE)) {
    // Query log on.
    $output .= $query_summary;
    $output .= t_safe(' Queries exceeding @threshold ms are <span class="marker">highlighted</span>.', array('@threshold' => variable_get('devel_execution', 5)));
  }

  if (variable_get('dev_timer', 0)) {
    $output .= devel_timer();
  }

  if (variable_get('devel_xhprof_enabled', FALSE)) {
    $output .= devel_xhprof_output();
  }

  $output .= devel_shutdown_memory();

  $output .= '</div>';

  return $output;
}

function devel_xhprof_output() {
  $namespace = variable_get('site_name', '');  // namespace for your application
  $xhprof_data = xhprof_disable();

  $xhprof_runs = new XHProfRuns_Default();
  $run_id = $xhprof_runs->save_run($xhprof_data, $namespace);
  // @todo: render results from within Drupal.
  $xhprof_url = variable_get('devel_xhprof_url', '');
  if ($xhprof_url) {
    return t('<a href="@xhprof">XHProf output</a>', array('@xhprof' => $xhprof_url . "/index.php?run=$run_id&source=$namespace"));
  }
}

function devel_shutdown_memory() {
  global $memory_init;

  if (variable_get('dev_mem', FALSE)) {
    $memory_shutdown = memory_get_usage();
    $args = array('@memory_boot' => round($memory_init / 1024 / 1024, 2), '@memory_shutdown' => round($memory_shutdown / 1024 / 1024, 2), '@memory_peak' => round(memory_get_peak_usage(TRUE) / 1024 / 1024, 2));
    $msg = '<span class="dev-memory-usages"> Memory used at: devel_boot()=<strong>@memory_boot</strong> MB, devel_shutdown()=<strong>@memory_shutdown</strong> MB, PHP peak=<strong>@memory_peak</strong> MB.</span>';
    // theme() may not be available. not t() either.
    return t_safe($msg, $args);
  }
}

function devel_shutdown_query($queries) {
  if (!empty($queries)) {
    if (function_exists('theme_get_registry') && theme_get_registry()) {
      // Safe to call theme('table).
      list($counts, $query_summary) = devel_query_summary($queries);
      $output = devel_query_table($queries, $counts);

      // Save all queries to a file in temp dir. Retrieved via AJAX.
      devel_query_put_contents($queries);
    }
    else {
      $output = '</div>' . dprint_r($queries, TRUE);
    }
    return $output;
  }
}

// Write the variables information to the a file. It will be retrieved on demand via AJAX.
function devel_query_put_contents($queries) {
  $request_id = mt_rand(1, 1000000);
  $path = "temporary://devel_querylog";

  // Create the devel_querylog within the temp folder, if needed.
  file_prepare_directory($path, FILE_CREATE_DIRECTORY);

  // Occassionally wipe the querylog dir so that files don't accumulate.
  if (mt_rand(1, 1000) == 401) {
    devel_empty_dir($path);
  }

  $path .= "/$request_id.txt";
  $path = file_stream_wrapper_uri_normalize($path);
  // Save queries as a serialized array.
  file_put_contents($path, serialize($queries));
  $settings['devel'] = array(
    // A random string that is sent to the browser. It enables the AJAX to retrieve queries from this request.
    'request_id' => $request_id,
  );
  print '<script type="text/javascript">jQuery.extend(Drupal.settings, '.  json_encode($settings) .");</script>\n";
}

function devel_query_enabled() {
  return method_exists('Database', 'getLog') && variable_get('devel_query_display', FALSE);
}

function devel_query_summary($queries) {
  if (variable_get('devel_query_display', FALSE) && is_array($queries)) {
    $sum = 0;
    foreach ($queries as $query) {
      $text[] = $query['query'];
      $sum += $query['time'];
    }
    $counts = array_count_values($text);
    return array($counts, t_safe('Executed @queries queries in @time ms.', array('@queries' => count($queries), '@time' => round($sum * 1000, 2))));
  }
}

function t_safe($string, $args) {
  // get_t caused problems here with theme registry after changing on admin/build/modules. the theme_get_registry call is needed.
  if (function_exists('t') && function_exists('theme_get_registry')) {
    theme_get_registry();
    return t($string, $args);
  }
  else {
    strtr($string, $args);
  }
}

function devel_get_core_version($version) {
  $version_parts = explode('.', $version);
  // Map from 4.7.10 -> 4.7
  if ($version_parts[0] < 5) {
    return $version_parts[0] .'.'. $version_parts[1];
  }
  // Map from 5.5 -> 5 or 6.0-beta2 -> 6
  else {
    return $version_parts[0];
  }
}

// See http://drupal.org/node/126098
function devel_is_compatible_optimizer() {
   ob_start();
   phpinfo();
   $info = ob_get_contents();
   ob_end_clean();

   // Match the Zend Optimizer version in the phpinfo information
   $found = preg_match('/Zend&nbsp;Optimizer&nbsp;v([0-9])\.([0-9])\.([0-9])/', $info, $matches);

   if ($matches) {
     $major = $matches[1];
     $minor = $matches[2];
     $build = $matches[3];

     if ($major >= 3) {
       if ($minor >= 3) {
         return TRUE;
       }
       elseif ($minor == 2 && $build >= 8) {
         return TRUE;
       }
       else {
         return FALSE;
       }
    }
    else {
      return FALSE;
    }
  }
  else {
    return TRUE;
  }
}

/**
 * Generates the execute block form.
 */
function devel_execute_form() {
  $form['code'] = array(
    '#type' => 'textarea',
    '#title' => t('PHP code to execute'),
    '#description' => t('Enter some code. Do not use <code>&lt;?php ?&gt;</code> tags.')
  );
  $form['op'] = array('#type' => 'submit', '#value' => t('Execute'));
  $form['#redirect'] = FALSE;
  $form['#skip_duplicate_check'] = TRUE;
  return $form;
}

/**
 * Process PHP execute form submissions.
 */
function devel_execute_form_submit($form, &$form_state) {
  ob_start();
  print eval($form_state['values']['code']);
  dsm(ob_get_clean());
}

/**
 * Switch from original user to another user and back.
 * We don't call session_save_session() because we really want to change users. Usually unsafe!
 *
 * @param $name The username to switch to.
 */
function devel_switch_user($name = NULL) {
  global $user;
  static $orig_user = array();

  if (isset($name)) {
    $user = user_load_by_name($name);
  }
  // Retrieve the initial user. Can be called multiple times.
  elseif (count($orig_user)) {
    $user = array_shift($orig_user);
    array_unshift($orig_user, $user);
  }
  // Store the initial user.
  else {
    $orig_user[] = $user;
  }
  drupal_goto();
}

/**
 * Print an object or array using either Krumo (if installed) or devel_print_object()
 *
 * @param $object
 *   array or object to print
 * @param $prefix
 *   prefixing for output items
 */
function kdevel_print_object($object, $prefix = NULL) {
  return has_krumo() ? krumo_ob($object) : devel_print_object($object, $prefix);
}

// Save krumo htlm using output buffering.
function krumo_ob($object) {
  ob_start();
  krumo($object);
  $output = ob_get_contents();
  ob_end_clean();
  return $output;
}

/**
 * Display an object or array
 *
 * @param $object
 *   the object or array
 * @param $prefix
 *   prefix for the output items (example "$node->", "$user->", "$")
 * @param $header
 *   set to FALSE to suppress the output of the h3
 */
function devel_print_object($object, $prefix = NULL, $header = TRUE) {
  drupal_add_css(drupal_get_path('module', 'devel') .'/devel.css');
  $output = '<div class="devel-obj-output">';
  if ($header) {
    $output .= '<h3>'. t('Display of !type !obj', array('!type' => str_replace(array('$', '->'), '', $prefix), '!obj' => gettype($object))) .'</h3>';
  }
  $output .= _devel_print_object($object, $prefix);
  $output .= '</div>';
  return $output;
}

/**
 * Recursive (and therefore magical) function goes through an array or object and
 * returns a nicely formatted listing of its contents.
 *
 * @param $obj
 *   array or object to recurse through
 * @param $prefix
 *   prefix for the output items (example "$node->", "$user->", "$")
 * @param $parents
 *   used by recursion
 * @param $object
 *   used by recursion
 * @return
 *   fomatted html
 *
 * @todo
 *   currently there are problems sending an array with a varname
 */
function _devel_print_object($obj, $prefix = NULL, $parents = NULL, $object = FALSE) {
  static $root_type, $out_format;

  // TODO: support objects with references. See http://drupal.org/node/234581.
  if (isset($obj->view)) {
    return;
  }

  if (!isset($root_type)) {
    $root_type = gettype($obj);
    if ($root_type == 'object') {
      $object = TRUE;
    }
  }

  if (is_object($obj)) {
    $obj = (array)$obj;
  }
  if (is_array($obj)) {
    $output = "<dl>\n";
    foreach ($obj as $field => $value) {
      if ($field == 'devel_flag_reference') {
        continue;
      }
      if (!is_null($parents)) {
        if ($object) {
          $field = $parents .'->'. $field;
        }
        else {
          if (is_int($field)) {
            $field = $parents .'['. $field .']';
          }
          else {
            $field = $parents .'[\''. $field .'\']';
          }
        }
      }

      $type = gettype($value);

      $show_summary = TRUE;
      $summary = NULL;
      if ($show_summary) {
        switch ($type) {
          case 'string' :
          case 'float' :
          case 'integer' :
            if (strlen($value) == 0) {
              $summary = t("{empty}");
            }
            elseif (strlen($value) < 40) {
              $summary = htmlspecialchars($value);
            }
            else {
              $summary = format_plural(drupal_strlen($value), '1 character', '@count characters');
            }
            break;
          case 'array' :
          case 'object' :
            $summary = format_plural(count((array)$value), '1 element', '@count elements');
            break;
          case 'boolean' :
            $summary = $value ? t('TRUE') : t('FALSE');
            break;
        }
      }
      if (!is_null($summary)) {
        $typesum = '('. $type .', <em>'. $summary .'</em>)';
      }
      else {
        $typesum = '('. $type .')';
      }

      $output .= '<span class="devel-attr">';
      $output .= "<dt><span class=\"field\">{$prefix}{$field}</span> $typesum</dt>\n";
      $output .= "<dd>\n";
      // Check for references.
      if (is_array($value) && isset($value['devel_flag_reference'])) {
        $value['devel_flag_reference'] = TRUE;
      }
      // Check for references to prevent errors from recursions.
      if (is_array($value) && isset($value['devel_flag_reference']) && !$value['devel_flag_reference']) {
        $value['devel_flag_reference'] = FALSE;
        $output .= _devel_print_object($value, $prefix, $field);
      }
      elseif (is_object($value)) {
        $value->devel_flag_reference = FALSE;
        $output .= _devel_print_object((array)$value, $prefix, $field, TRUE);
      }
      else {
        $value = is_bool($value) ? ($value ? 'TRUE' : 'FALSE') : $value;
        $output .= htmlspecialchars(print_r($value, TRUE)) ."\n";
      }
      $output .= "</dd></span>\n";
    }
    $output .= "</dl>\n";
  }
  return $output;
}

/**
 * Adds a table at the bottom of the page cataloguing data on all the database queries that were made to
 * generate the page.
 */
function devel_query_table($queries, $counts) {
  $version = devel_get_core_version(VERSION);
  $header = array ('ms', '#', 'where', 'ops', 'query', 'target');
  $i = 0;
  $api = variable_get('devel_api_url', 'api.drupal.org');
  foreach ($queries as $query) {
    $function = !empty($query['caller']['class']) ? $query['caller']['class'] . '::' : '';
    $function .= $query['caller']['function'];
    $count = isset($counts[$query['query']]) ? $counts[$query['query']] : 0;

    $diff = round($query['time'] * 1000, 2);
    if ($diff > variable_get('devel_execution', 5)) {
      $cell[$i][] = array ('data' => $diff, 'class' => 'marker');
    }
    else {
      $cell[$i][] = $diff;
    }
    $cell[$i][] = $count;
    $cell[$i][] = l($function, "http://$api/api/$version/function/$function");
    $ops[] = l('P', '', array('attributes' => array('title' => 'Show placeholders', 'class' => 'dev-placeholders', 'qid' => $i)));
    $ops[] = l('A', '', array('attributes' => array('title' => 'Show arguments', 'class' => 'dev-arguments', 'qid' => $i)));
    // EXPLAIN only valid for select queries.
    if (strpos($query['query'], 'UPDATE') === FALSE && strpos($query['query'], 'INSERT') === FALSE && strpos($query['query'], 'DELETE') === FALSE) {
      $ops[] = l('E', '', array('attributes' => array('title' => 'Show EXPLAIN', 'class' => 'dev-explain', 'qid' => $i)));
    }
    $cell[$i][] = implode(' ', $ops);
    // 3 divs for each variation of the query. Last 2 are hidden by default.
    $placeholders = '<div class="dev-placeholders">' . check_plain($query['query']) . "</div>\n";
    $args = '<div class="dev-arguments" style="display: none;"></div>' . "\n";
    $explain = '<div class="dev-explain" style="display: none;"></div>' . "\n";
    $cell[$i][] = array(
      'id' => "devel-query-$i",
      'data' => $placeholders . $args . $explain,
    );
    $cell[$i][] = $query['target'];
    $i++;
    unset($diff, $count, $ops);
  }
  if (variable_get('devel_query_sort', DEVEL_QUERY_SORT_BY_SOURCE)) {
    usort($cell, '_devel_table_sort');
  }
  return theme('devel_querylog', array('header' => $header, 'rows' => $cell));
}

function theme_devel_querylog_row($variables) {
  $row = $variables['row'];
  $i = 0;
  $output = '';
  foreach ($row as $cell) {
    $i++;

    if (is_array($cell)) {
      $data = !empty($cell['data']) ? $cell['data'] : '';
      unset($cell['data']);
      $attr = $cell;
    }
    else {
      $data = $cell;
      $attr = array();
    }

    if (!empty($attr['class'])) {
      $attr['class'] .= " cell cell-$i";
    }
    else {
      $attr['class'] = "cell cell-$i";
    }
    $attr = drupal_attributes($attr);

    $output .= "<div $attr>$data</div>";
  }
  return $output;
}

function theme_devel_querylog($variables) {
  $header = $variables['header'];
  $rows = $variables['rows'];
  $output = '';
  if (!empty($header)) {
    $output .= "<div class='devel-querylog devel-querylog-header clear-block'>";
    $output .= theme('devel_querylog_row', array('row' => $header));
    $output .= "</div>";
  }
  if (!empty($rows)) {
    $i = 0;
    foreach ($rows as $row) {
      $i++;
      $zebra = ($i % 2) == 0 ? 'even' : 'odd';
      $output .= "<div class='devel-querylog devel-querylog-$zebra clear-block'>";
      $output .= theme('devel_querylog_row', array('row' => $row));
      $output .= "</div>";
    }
  }
  return $output;
}

function _devel_table_sort($a, $b) {
  $a = is_array($a[0]) ? $a[0]['data'] : $a[0];
  $b = is_array($b[0]) ? $b[0]['data'] : $b[0];
  if ($a < $b) {
    return 1;
  }
  if ($a > $b) {
    return -1;
  }
  return 0;
}

/**
 * Displays page execution time at the bottom of the page.
 */
function devel_timer() {
  $time = timer_read('page');
  return t_safe(' Page execution time was @time ms.', array('@time' => $time));
}

// An alias for drupal_debug().
function dd($data, $label = NULL) {
  return drupal_debug($data, $label);
}

// Log any variable to a drupal_debug.log in the site's temp directory.
// See http://drupal.org/node/314112
function drupal_debug($data, $label = NULL) {
  ob_start();
  print_r($data);
  $string = ob_get_clean();
  if ($label) {
    $out = $label .': '. $string;
  }
  else {
    $out = $string;
  }
  $out .= "\n";

  // The temp directory does vary across multiple simpletest instances.
  $file = file_directory_path('temporary') . '/drupal_debug.txt';
  if (file_put_contents($file, $out, FILE_APPEND) === FALSE) {
    drupal_set_message(t('The file could not be written.'), 'error');
    return FALSE;
  }
}

/**
 * Prints the arguments passed into the current function
 */
function dargs($always = TRUE) {
  static $printed;
  if ($always || !$printed) {
    $bt = debug_backtrace();
    print kdevel_print_object($bt[1]['args']);
    $printed = TRUE;
  }
}

/**
 * Print a variable to the 'message' area of the page. Uses drupal_set_message()
 */
function dpm($input, $name = NULL) {
  if (user_access('access devel information')) {
    $export = kprint_r($input, TRUE, $name);
    drupal_set_message($export);
  }
}

/**
 * Var_dump() a variable to the 'message' area of the page. Uses drupal_set_message()
 */
function dvm($input, $name = NULL) {
  if (user_access('access devel information')) {
    $export = dprint_r($input, TRUE, $name, 'var_dump', FALSE);
    drupal_set_message($export);
  }
}

// legacy function that was poorly named. use dpm() instead, since the 'p' maps to 'print_r'
function dsm($input, $name = NULL) {
  dpm($input, $name);
}

/**
 * An alias for dprint_r(). Saves carpal tunnel syndrome.
 */
function dpr($input, $return = FALSE, $name = NULL) {
  return dprint_r($input, $return, $name);
}

/**
 * An alias for kprint_r(). Saves carpal tunnel syndrome.
 */
function kpr($input, $return = FALSE, $name = NULL) {
  return kprint_r($input, $return, $name);
}

/**
 * Like dpr, but uses var_dump() instead
 */
function dvr($input, $return = FALSE, $name = NULL) {
  return dprint_r($input, $return, $name, 'var_dump', FALSE);
}

function kprint_r($input, $return = FALSE, $name = NULL, $function = 'print_r') {
  // We do not want to krumo() strings and integers and such
  if (merits_krumo($input)) {
    if (user_access('access devel information')) {
      return $return ? (isset($name) ? $name .' => ' : '') . krumo_ob($input) : krumo($input);
    }
  }
  else {
    return dprint_r($input, $return, $name, $function);
  }
}

/**
 * Pretty-print a variable to the browser (no krumo).
 * Displays only for users with proper permissions. If
 * you want a string returned instead of a print, use the 2nd param.
 */
function dprint_r($input, $return = FALSE, $name = NULL, $function = 'print_r', $check= TRUE) {
  if (user_access('access devel information')) {
    if ($name) {
      $name .= ' => ';
    }
    ob_start();
    $function($input);
    $output = ob_get_clean();
    if ($check) {
      $output = check_plain($output);
    }
    if (count($input, COUNT_RECURSIVE) > DEVEL_MIN_TEXTAREA) {
        // don't use fapi here because sometimes fapi will not be loaded
        $printed_value = "<textarea rows=30 style=\"width: 100%;\">\n". $name . $output .'</textarea>';
    }
    else {
      $printed_value = '<pre>'. $name . $output .'</pre>';
    }

    if ($return) {
      return $printed_value;
    }
    else {
      print $printed_value;
    }
  }
}

/**
 * Print the function call stack.
 */
function ddebug_backtrace() {
  if (user_access('access devel information')) {
    $trace = debug_backtrace();
    array_shift($trace);
    foreach ($trace as $key => $value) {
      $rich_trace[$value['function']] = $value;
    }
    if (has_krumo()) {
      print krumo($rich_trace);
    }
    else {
      dprint_r($rich_trace);
    }
  }
}

// Delete all files in a dir. http://www.plus2net.com/php_tutorial/php-files-delete.php
function devel_empty_dir($dir) {
  foreach (new DirectoryIterator($dir) as $fileInfo) {
    unlink($fileInfo->getPathname());
  }
}

/*
 * migration related functions
 */


/**
 * Update node_comment_statistics table for nodes with comments.
 * TODO: if 2 comments have exact same timestamp, the function can get wrong uid and name fields.
 * Handles when comment timestamps have been manually set in admin
 *
 * @return void
 **/
function devel_rebuild_node_comment_statistics() {
  // Empty table
  db_delete('node_comment_statistics');

  $sql = "INSERT INTO {node_comment_statistics} (nid, last_comment_timestamp, last_comment_name, last_comment_uid, comment_count) (SELECT nid, c.timestamp, name, uid, comment_count FROM {comments} c INNER JOIN (SELECT MAX(timestamp) AS timestamp, COUNT(*) AS comment_count FROM {comments} WHERE status=%d GROUP BY nid) AS c2 ON c.timestamp=c2.timestamp)";
  db_query($sql, COMMENT_PUBLISHED);

  // Insert 0 count records into the node_comment_statistics for nodes that are missing. See comment_enable()
  db_query_temporary("SELECT n.nid, n.changed, n.uid FROM {node} n LEFT JOIN {node_comment_statistics} c ON n.nid = c.nid WHERE c.comment_count IS NULL", 'missing_nids');
  db_query("INSERT INTO {node_comment_statistics} (nid, last_comment_timestamp, last_comment_name, last_comment_uid, comment_count) SELECT n.nid, n.changed, NULL, n.uid, 0 FROM missing_nids n");
}