scanner.module

<?php
/**
 * @file
 * Search and Replace Scanner - works on all nodes text content.
 *
 * The Search and Replace Scanner can do regular expression matches
 * against the title, body and CCK text content fields on all nodes in your system.
 * This is useful for finding html strings that Drupal's normal search will
 * ignore. And it can replace the matched text. Very handy if you are changing
 * the name of your company, or are changing the URL of a link included
 * multiple times in multiple nodes.
 *
 * The module allow you to configure which fields and tables to work with,
 * and also to add in custom tables and fields for modules that don't use CCK.
 *
 * Limitations:
 *  Only works with Mysql
 *
 * Warning:
 *  This is a very powerful tool, and as such is very dangerous.  You can
 *  easy distroy your entire site with it.  Be sure to backup your database
 *  before using it.  No, really.
 *
 * Todo:
 *  Provide better highlighting for search results
 *   - right now there's a known bug where multiple search terms
 *     on the same line aren't all highlighted. (The hit count
 *     is correct, though, and all items are replaced correctly.)
 *
 * Credits:
 *  Version 5.x-1.0 by:
 *   - Tao Starbow http://www.starbowconsulting.com
 *     Drupal username: starbow
 *  Version 5.x-2.0 by:
 *   - Amit Asaravala http://www.returncontrol.com
 *     Drupal username: aasarava
 *   - Jason Salter jason http://www.fivepaths.com
 *     Drupal username: jpsalter
 *   - Sponsored by Five Paths Consulting http://www.fivepaths.com
 *  Version 7.x-1.0 by:
 *   - Michael Rossetti - http://www.mit.edu
 *     Drupal username: MikeyR
 */


//The special characters to escape if a search string is not a regex string:
define('SCANNER_REGEX_CHARS', '.\/+*?[^]$() {}=!<>|:');

//The modes that the search-and-replace process can be in.
//We need to track the modes to prevent accidentally starting a replacement
// or a long search if a user leaves mid-way through the process
// and comes back again w/ the same session variables.
define('SCANNER_STATUS_GO_SEARCH', 1);
define('SCANNER_STATUS_GO_CONFIRM', 2);
define('SCANNER_STATUS_GO_REPLACE', 3);


/**
 * Implements hook_menu().
 */
function scanner_menu() {

  $items['admin/content/scanner'] = array(
    'title' => 'Search and Replace Scanner',
    'description' => 'Find (and replace) keywords in all your content.',
    'page callback' => 'scanner_view',
    'access arguments' => array('perform search and replace'),
  );
  $items['admin/content/scanner/scan'] = array(
    'title' => 'Search',
    'access arguments' => array('perform search and replace'),
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/content/scanner/scan/confirm'] = array(
    'title' => 'Confirm Replace',
    'access arguments' => array('perform search and replace'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('scanner_confirm_form'),
    'type' => MENU_CALLBACK,
  );
  $items['admin/content/scanner/undo/confirm'] = array(
    'title' => 'Confirm Undo',
    'access arguments' => array('perform search and replace'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('scanner_undo_confirm_form'),
    'type' => MENU_CALLBACK,
  );
  $items['admin/content/scanner/settings'] = array(// Shows up on scanner page as tab.
    'title' => 'Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('scanner_admin_form'),
    'access arguments' => array('administer scanner settings'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 1,
  );
  $items['admin/content/scanner/undo'] = array(// Shows up on scanner page as tab.
    'title' => 'Undo',
    'page callback' => 'scanner_undo_page',
    'access arguments' => array('perform search and replace'),
    'type' => MENU_LOCAL_TASK,
  );
  $items['admin/config/scanner'] = array(// Shows up on admin page.
    'title' => 'Search and Replace Scanner',
    'description' => 'Configure defaults and what fields can be searched and replaced.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('scanner_admin_form'),
    'access arguments' => array('administer scanner settings'),
  );
  return $items;
}

/**
 * @todo Please document this function.
 * @see http://drupal.org/node/1354
 */
function scanner_theme() {
  return array(
    'scanner_results' => array(
      'file' => 'scanner.module',
      'variables' => array(
        'results' => NULL,
      ),
    ),
    'scanner_item' => array(
      'file' => 'scanner.module',
      'variables' => array(
        'item' => NULL,
      ),
    ),
    'scanner_replace_results' => array(
      'file' => 'scanner.module',
      'variables' => array(
        'results' => NULL,
      ),
    ),
    'scanner_replace_item' => array(
      'file' => 'scanner.module',
      'variables' => array(
        'item' => NULL,
      ),
    ),
  );
}


/**
 * Implements hook_permission().
 */
function scanner_permission() {
  return array(
    'administer scanner settings' => array(
      'title' => t('administer scanner settings'),
      'description' => t('TODO Add a description for \'administer scanner settings\''),
    ),
    'perform search and replace' => array(
      'title' => t('perform search and replace'),
      'description' => t('TODO Add a description for \'perform search and replace\''),
    ),
  );
}

/**
 * Menu callback; presents the scan form and results.
 */
function scanner_view() {
    
  $output='';
  
  //using set_html_head because it seems unecessary to load a separate css
  // file for just two simple declarations:
  drupal_add_css('
      #scanner-form .form-submit { margin-top:0; }
      #scanner-form .form-item { margin-bottom:0; }
    ', array('type' => 'inline'));

  //javascript checks to make sure user has entered some search text:
  drupal_add_js("
    $(document).ready(function() {
      $('input[@type=submit][@value=Search]').click(function() {
        var searchfield = $('#edit-search');
        var chars = searchfield.val().length;
        if (chars == 0) {
          alert('Please provide some search text and try again.');
          searchfield.addClass('error');
          searchfield[0].focus();
          return FALSE;
        } else if (chars < 3) {
          return confirm('Searching for a keyword that has fewer than three characters could take a long time. Are you sure you want to continue?');
        }
        return TRUE;
      });
    });
  ", array('type' => 'inline', 'scope' => JS_DEFAULT));
  
  if (isset($_SESSION['scanner_search'])) {
    $search = $_SESSION['scanner_search'];
  }
  else{
    $search = NULL;
  }
  
  if (isset($_SESSION['scanner_status'])) {
    $status = $_SESSION['scanner_status'];
  }
  else{
      $status = NULL;
  }
  
  if (!is_NULL($search) && $status >= SCANNER_STATUS_GO_SEARCH) {

    if ($status == SCANNER_STATUS_GO_CONFIRM) {
      drupal_goto('admin/content/scanner/scan/confirm');

    }
    elseif ($status == SCANNER_STATUS_GO_REPLACE) {
      $resulttxt = '<a name="results"></a>' . t('Replacement Results');
      $results = scanner_execute('replace');

    }
    else {
      $resulttxt = t('Search Results');
      $results = scanner_execute('search');
    }

    if ($results) {
      // TODO Please change this theme call to use an associative array for the $variables parameter.
      $results = '<a name="results"></a><div><h2>' . $resulttxt . '</h2>' . $results;
    }
    else {
      // TODO Please change this theme call to use an associative array for the $variables parameter.
      $results = t('Your search yielded no results.');
    }
    
    $output = drupal_render(drupal_get_form('scanner_form'));
    $output .= $results;

    //clear any old search form input:
    unset($_SESSION['scanner_search']);
    unset($_SESSION['scanner_replace']);
    unset($_SESSION['scanner_preceded']);
    unset($_SESSION['scanner_followed']);
    unset($_SESSION['scanner_mode']);
    unset($_SESSION['scanner_wholeword']);
    unset($_SESSION['scanner_published']);
    unset($_SESSION['scanner_regex']);
    unset($_SESSION['scanner_terms']);
    //clear old status:
    unset($_SESSION['scanner_status']);

    return $output;
  }
   
  $output .= drupal_render(drupal_get_form('scanner_form'));
  
  return $output;
}

/**
 * The search and replace form.
 *
 * @param str $search - regex to search for.
 * @param str $replace - string to substitute.
 * @return $form
 */
function scanner_form($node, &$form_state) {
    
  $form = array();

  if (isset($_SESSION['scanner_search'])) {
  $search = $_SESSION['scanner_search'];
  }
  else{
      $search = NULL;
  }
  
  if (isset($_SESSION['scanner_replace'])) {
  $replace = $_SESSION['scanner_replace'];   
  }
  else{
      $replace = NULL;
  }
  if (isset($_SESSION['scanner_preceded'])) {
    $preceded = $_SESSION['scanner_preceded'];
  }
  else{
      $preceded = NULL;
  }
  
  if (isset($_SESSION['scanner_followed'])) {
    $followed = $_SESSION['scanner_followed'];
  }
  else{
      $followed = NULL;
  }
  
  $mode = isset($_SESSION['scanner_mode']) ? $_SESSION['scanner_mode'] : variable_get('scanner_mode', 0);
  $wholeword = isset($_SESSION['scanner_wholeword']) ? $_SESSION['scanner_wholeword'] : variable_get('scanner_wholeword', 0);
  $published = isset($_SESSION['scanner_published']) ? $_SESSION['scanner_published'] : variable_get('scanner_published', 1);
  $regex = isset($_SESSION['scanner_regex']) ? $_SESSION['scanner_regex'] : variable_get('scanner_regex', 0);
  
  if (isset($_SESSION['scanner_terms'])) {
    $terms = $_SESSION['scanner_terms'];
  }
  else{
      $terms = NULL;
  }
  
  $form['search'] = array(
    '#type' => 'textfield',
    '#default_value' => $search,
    '#title' => t('Step 1: Search for'),
    '#maxlength' => 256,
  );
  $form['submit_search'] = array(
    '#type' => 'submit',
    '#value' => t('Search'),
  );

  $form['replace'] = array(
    '#type' => 'textfield',
    '#default_value' => $replace,
    '#title' => t('Step 2: Replace with'),
    '#maxlength' => 256,
  );
  $form['submit_replace'] = array(
    '#type' => 'submit',
    '#value' => t('Replace'),
  );

  $form['options'] = array(
    '#type' => 'fieldset',
    '#title' => t('Search Options'),
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );

  $form['options']['surrounding'] = array(
    '#type' => 'fieldset',
    '#title' => t('Surrounding Text'),
    '#collapsible' => FALSE,
    '#description' => t('You can limit matches by providing the text that should appear immediately before or after the search text. Remember to account for spaces.  Note: Case sensitivity and regular expression options will all apply here, too. Whole word is not recommended.'),
  );

  $form['options']['surrounding']['preceded'] = array(
    '#type' => 'textfield',
    '#title' => t('Preceded by'),
    '#default_value' => $preceded,
    '#maxlength' => 256,
  );

  /* TODO: for possible future implementation...
   * Depends on whether negative lookahead and negative lookbehind
   *  can accurately be approximated in MySQL...
   $form['options']['surrounding']['notpreceded'] = array(
   '#type' => 'checkbox',
   '#title' => t('NOT preceded by the text above'),
   '#default_value' => $notpreceded,
   );
   */

  $form['options']['surrounding']['followed'] = array(
    '#type' => 'textfield',
    '#title' => t('Followed by'),
    '#default_value' => $followed,
    '#maxlength' => 256,
  );

  /* TODO: for possible future implementation...
   * Depends on whether negative lookahead and negative lookbehind
   *  can accurately be approximated in MySQL...
   $form['options']['surrounding']['notfollowed'] = array(
   '#type' => 'checkbox',
   '#title' => t('NOT followed by the text above'),
   '#default_value' => $notfollowed,
   );
   */

  $form['options']['mode'] = array(
    '#type' => 'checkbox',
    '#title' => t('Case sensitive search'),
    '#default_value' => $mode,
    '#description' => t("Check this if the search should only return results that exactly match the capitalization of your search terms."),
  );

  $form['options']['wholeword'] = array(
    '#type' => 'checkbox',
    '#title' => t('Match whole word'),
    '#default_value' => $wholeword,
    '#description' => t("Check this if you don't want the search to match any partial words. For instance, if you search for 'run', a whole word search will <em>not</em> match 'running'."),
  );

  $form['options']['regex'] = array(
    '#type' => 'checkbox',
    '#title' => t('Use regular expressions in search'),
    '#default_value' => $regex,
    '#description' => t('Check this if you want to use regular expressions in your search terms.'),
  );

  $form['options']['published'] = array(
    '#type' => 'checkbox',
    '#title' => t('Published nodes only'),
    '#default_value' => $published,
    '#description' => t('Check this if you only want your search and replace to affect fields in nodes that are published.'),
  );

  $scanner_vocabularies = array_filter(variable_get('scanner_vocabulary', array()));
  

  if (count($scanner_vocabularies)) {

    $vocabularies = taxonomy_get_vocabularies();
    $options = array();

    foreach ($vocabularies as $vid => $vocabulary) {
      if (in_array($vid, $scanner_vocabularies) ) {
        $tree = taxonomy_get_tree($vid);
        if ($tree && (count($tree) > 0)) {
          $options[$vocabulary->name] = array();
          foreach ($tree as $term) {
            $options[$vocabulary->name][$term->tid] = str_repeat('-', $term->depth) . $term->name;
          }
        }
      }
    }

    $form['options']['terms'] = array(
      '#type' => 'select',
      '#title' => t('Only match nodes with these terms'),
      '#options' => $options,
      '#default_value' => $terms,
      '#multiple' => TRUE,
    );
  }
  
  return $form;
}

/**
 * Validate form input.
 */
function scanner_form_validate($form, &$form_state) {
  $search = trim($form_state['values']['search']);
  if ($search == '') {
    form_set_error('search', t('Please enter some keywords.'));
  }
}

/**
 * Handles submission of the search and replace form.
 *
 * @param $form
 * @param $form_state
 * @return the new path that will be goto'ed.
 */
function scanner_form_submit($form, &$form_state) {
  //save form input:

  $_SESSION['scanner_search']    = $form_state['values']['search'];
  $_SESSION['scanner_preceded']  = $form_state['values']['preceded'];
  //$_SESSION['scanner_notpreceded'] = $form_state['values']['notpreceded'];
  $_SESSION['scanner_followed']  = $form_state['values']['followed'];
  //$_SESSION['scanner_notfollowed'] = $form_state['values']['notfollowed'];
  $_SESSION['scanner_mode']      = $form_state['values']['mode'];
  $_SESSION['scanner_wholeword'] = $form_state['values']['wholeword'];
  $_SESSION['scanner_published'] = $form_state['values']['published'];
  $_SESSION['scanner_regex']     = $form_state['values']['regex'];
  if (isset($form_state['values']['terms'])) {
  $_SESSION['scanner_terms']     = $form_state['values']['terms'];
  }
  $_SESSION['scanner_replace']   = $form_state['values']['replace'];

  /* TODO The 'op' element in the form values is deprecated.
   Each button can have #validate and #submit functions associated with it.
   Thus, there should be one button that submits the form and which invokes
   the normal form_id_validate and form_id_submit handlers. Any additional
   buttons which need to invoke different validate or submit functionality
   should have button-specific functions. */
  if ($form_state['values']['op'] == 'Replace') {
    $_SESSION['scanner_status'] = SCANNER_STATUS_GO_CONFIRM;
  }
  else {
    $_SESSION['scanner_status'] = SCANNER_STATUS_GO_SEARCH;
  }
  $form_state['redirect'] = 'admin/content/scanner';
}


/**
 * Scanner confirmation form to prevent people from accidentally
 * replacing things they don't intend to.
 */
function scanner_confirm_form($form, &$form_state) {
  //using set_html_head because it seems unecessary to load a separate css
  // file for just one declaration:
  //you can override the styles by declaring with something "higher up"
  // the chain, like:  #wrapper #scanner-confirm-form .scanner-buttons .scanner-button-msg {...}
  drupal_add_css('
      #scanner-confirm-form .scanner-buttons .scanner-button-msg {
        position:absolute;
        top:0; left:0; z-index:100;
        width:100%; height:100%;
        background-color:#000; opacity:0.75;
        font-size:1.2em;
      }
      #scanner-confirm-form .scanner-buttons .scanner-button-msg p {
        color:#fff;
      }
    ', array('type' => 'inline'));

  //javascript to prevent further clicks on confirmation button after it's clicked once.
  //unfortunately we can't just use css disable to disable the button because then
  // the op values aren't sent to drupal correctly.
  drupal_add_js("
    $(document).ready(function() {
      $('input[@type=submit][@value=Yes, Continue]').click(function() {
        $('.scanner-buttons').css('position','relative')
          .append('<div class=\"scanner-button-msg\"><p>Replacing items... please wait...</p></div>')
        $('.scanner-button-msg').click(function() { return false; });
        return true;
      });
    });
  ", array('type' => 'inline', 'scope' => JS_DEFAULT));

  $form = array();

  $search    = $_SESSION['scanner_search'];
  $replace   = $_SESSION['scanner_replace'];
  $preceded  = $_SESSION['scanner_preceded'];
  $followed  = $_SESSION['scanner_followed'];
  $wholeword = $_SESSION['scanner_wholeword'];
  $regex     = $_SESSION['scanner_regex'];
  $mode      = $_SESSION['scanner_mode'];

  $modetxt = ($mode) ? t('Case sensitive') : t('Not case sensitive: will replace any matches regardless of capitalization.');

  $msg = (
    '<p>' . t('Are you sure you want to make the following replacement?') . '</p>' .
    '<div class="scanner-confirm">' .
    '  <label>' . t('Search for') . ':</label> [' . check_plain($search) . ']' .
    '</div>'
  );
  if ($preceded) {
    $msg .= (
      '<div class="scanner-confirm">' .
      '  <label>' . t('Preceded by') . ':</label> [' . check_plain($preceded) . ']' .
      '</div>'
    );
  }
  if ($followed) {
    $msg .= (
      '<div class="scanner-confirm">' .
      '  <label>' . t('Followed by') . ':</label> [' . check_plain($followed) . ']' .
      '</div>'
    );
  }
  $msg .= (
    '<div class="scanner-confirm">' .
    '  <label>' . t('Replace with') . ':</label> [' . check_plain($replace) . ']'
  );
  if ($replace === '') {
    $msg .= ' <span class="warning">This will delete any occurences of the search terms!</span>';
  }
  $msg .= (
    '</div>' .
    '<div class="scanner-confirm">' .
    '  <label>' . t('Mode') . ':</label> ' . $modetxt .
    '</div>'
  );
  if ($wholeword) {
    $msg .= (
      '<div class="scanner-confirm">' .
      '  <label>' . t('Match whole word') . ':</label> ' . t('Yes') .
      '</div>'
    );
  }
  if ($regex) {
    $msg .= (
      '<div class="scanner-confirm">' .
      '  <label>' . t('Use regular expressions') . ':</label> ' . t('Yes') .
      '</div>'
    );
  }

  $form['warning'] = array(
    '#type' => 'item',
    '#markup' => $msg,
  );

  $form['confirm'] = array(
    '#type' => 'submit',
    '#value' => t('Yes, Continue'),
    '#prefix' => '<div class="scanner-buttons">', //see suffix in cancel button element
  );
  $form['cancel'] = array(
    '#type' => 'submit',
    '#value' => t('No, Cancel'),
    '#suffix' => '</div>', //see prefix in confirm button element
  );
  
  return $form;
}


/**
 * Submission handling for scanner confirmation form.
 */
function scanner_confirm_form_submit($form, &$form_state) {
  /* TODO The 'op' element in the form values is deprecated.
   Each button can have #validate and #submit functions associated with it.
   Thus, there should be one button that submits the form and which invokes
   the normal form_id_validate and form_id_submit handlers. Any additional
   buttons which need to invoke different validate or submit functionality
   should have button-specific functions. */
  if ($form_state['values']['op'] == t('Yes, Continue')) {
    $_SESSION['scanner_status'] = SCANNER_STATUS_GO_REPLACE;
  }
  else {
    unset($_SESSION['scanner_status']);
  }

  $form_state['redirect'] = 'admin/content/scanner';
}

/**
 * @todo Please document this function.
 * @see http://drupal.org/node/1354
 */
function scanner_undo_page() {
  $header = array(t('Date'), t('Searched'), t('Replaced'), t('Count'), t('Operation'));

  $undoQuery = db_select('scanner', 's');
  $undoQuery->fields('s', array('undo_id', 'time', 'searched', 'replaced', 'count', 'undone'))
            ->orderBy('undo_id', 'DESC');
  
  $sandrs = $undoQuery->execute();

  $rows = array();
  
  foreach ($sandrs as $sandr) {

    if ($sandr->undone) {
      $operation = l(t('Redo'), 'admin/content/scanner/undo/confirm', array('query' => array('undo_id' => $sandr->undo_id)));
    }
    else {
      $operation = l(t('Undo'), 'admin/content/scanner/undo/confirm', array('query' => array('undo_id' => $sandr->undo_id)));
    }

    $rows[] = array(
      format_date($sandr->time),
      check_plain($sandr->searched),
      check_plain($sandr->replaced),
      $sandr->count,
      $operation,
    );
  }
 
  return theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => NULL, 'caption' => 'Prior Search and Replace Events'));
}

/**
 * @todo Please document this function.
 * @see http://drupal.org/node/1354
 */
function scanner_undo_confirm_form($form, &$form_state) {
       
  $undo_id = $_GET['undo_id'];

  if ($undo_id > 0) {
    
    $query = db_select('scanner', 's');
    $query->fields('s', array('undo_id', 'searched', 'replaced'))
          ->condition('undo_id', $undo_id, '=');
    
    $result = $query->execute();
    
    foreach ($result as $undo) {
        $undo = $undo;
    }
    
  }

  if ($undo->undo_id > 0) {
    $form['info'] = array(
      '#markup' => '<h2>' . t('Do you want to undo:') . '</h2>' .
                  '<h3>' . t('Searched for:') . '</h3>' .
                  '<p>[<em>' . check_plain($undo->searched) . '</em>]</p>' .
                  '<h3>' . t('Replaced with:') . '</h3>' .
                  '<p>[<em>' . check_plain($undo->replaced) . '</em>]</p>',
    );

    $form['undo_id'] = array(
      '#type' => 'hidden',
      '#value' => $undo->undo_id,
    );

    $form['confirm'] = array(
      '#type' => 'submit',
      '#value' => t('Yes, Continue'),
    );

    $form['cancel'] = array(
      '#type' => 'submit',
      '#value' => t('No, Cancel'),
    );

  }
  else {
    $form['info'] = array(
      '#value' => '<h2>' . t('No undo event was found') . '</h2>',
    );
  }

  return $form;
}

/**
 * @todo Please document this function.
 * @see http://drupal.org/node/1354
 */
function scanner_undo_confirm_form_submit($form, &$form_state) {

  /* TODO The 'op' element in the form values is deprecated.
   Each button can have #validate and #submit functions associated with it.
   Thus, there should be one button that submits the form and which invokes
   the normal form_id_validate and form_id_submit handlers. Any additional
   buttons which need to invoke different validate or submit functionality
   should have button-specific functions. */
  if ($form_state['values']['op'] == t('Yes, Continue')) {
    
    $query = db_select('scanner', 's');
    $query->fields('s', array('undo_data', 'undone'))
          ->condition('undo_id', $form_state['values']['undo_id'], '=');
    
    $results = $query->execute();
    
    foreach ($results as $undo) {
          $undo = $undo;
    }
    
    $undos = unserialize($undo->undo_data);
    
    $count = NULL;
    
    foreach ($undos as $nid => $sandr_event) {

      if ($undo->undone == 0) {
        $vid = $sandr_event['old_vid'];
        $undone = 1;
      }
      else {
        $vid = $sandr_event['new_vid'];
        $undone = 0;
      }

      $node = node_load($nid, $vid);

      $node->revision = TRUE;
      $node->log = t('Copy of the revision from %date via Search and Replace Undo', array('%date' => format_date($node->revision_timestamp)));

      node_save($node);
      ++$count;

    }

    drupal_set_message($count . ' ' . t('Nodes reverted'));
    // TODO Please review the conversion of this statement to the D7 database API syntax.

    db_update('scanner')
    ->fields(array(
      'undone' => $undone,
    ))
    ->condition('undo_id', $form_state['values']['undo_id'])
    ->execute();

  }
  else {
    drupal_set_message(t('Undo / Redo canceled'));
  }

  $form_state['redirect'] = 'admin/content/scanner/undo';
  $form_state['nid'] = $node->nid;
}

/**
 * Handles the actual search and replace.
 *
 * @param str $searchtype - either 'search', or 'replace'
 * @return The themed results.
 */
function scanner_execute($searchtype = 'search') {
  global $user;

  // variables to monitor possible timeout
  $max_execution_time = ini_get('max_execution_time');
  $start_time = REQUEST_TIME;
  $expanded = FALSE;

  // get process and undo data if saved from timeout
  $processed = variable_get('scanner_partially_processed_' . $user->uid, array());
  $undo_data = variable_get('scanner_partial_undo_' . $user->uid, array());

  unset($_SESSION['scanner_status']);
  $results = NULL;
  $search      = $_SESSION['scanner_search'];
  $replace     = $_SESSION['scanner_replace'];
  $preceded    = $_SESSION['scanner_preceded'];
  //$notpreceded = $_SESSION['scanner_notpreceded'];
  $followed    = $_SESSION['scanner_followed'];
  //$notfollowed = $_SESSION['scanner_notfollowed'];
  $mode        = $_SESSION['scanner_mode'];
  $wholeword   = $_SESSION['scanner_wholeword'];
  $published   = $_SESSION['scanner_published'];
  $regex       = $_SESSION['scanner_regex'];
  if (isset($_SESSION['scanner_terms'])) {
  $terms       = $_SESSION['scanner_terms'];
  }
  else{
      $terms = NULL;
  }
  
  if ($searchtype == 'search') {
    drupal_set_message(t('Scanning for: [%search] ...', array('%search' => $search)));
  }
  else { //searchtype == 'replace'
    drupal_set_message(t('Replacing [%search] with [%replace] ...', array('%search' => $search, '%replace' => $replace)));
  }

  if ($mode) { // Case Sensitive
    $flag = NULL;
  }
  else { // Case Insensitive
    $flag = 'i'; //ci flag for use in php preg_search and preg_replace
  }

  
  $preceded_php = '';
  if (!empty($preceded)) {
    if (!$regex) {
      $preceded = addcslashes($preceded, SCANNER_REGEX_CHARS);
    }
    $preceded_php = '(?<=' . $preceded . ')';
  }
  $followed_php = '';
  if (!empty($followed)) {
    if (!$regex) {
      $followed = addcslashes($followed, SCANNER_REGEX_CHARS);
    }
    $followed_php = '(?=' . $followed . ')';
  }

  //Case 1:
  if ($wholeword && $regex) {
    $where = "[[:<:]]" . $search . "[[:>:]]";
    $search_db = $preceded . $search . $followed;
    $search_php = '\b' . $preceded_php . $search . $followed_php . '\b';
  }
  //Case 2:
  elseif ($wholeword && !$regex) {
    $where = "[[:<:]]" . $search . "[[:>:]]";
    $search_db = $preceded . addcslashes($search, SCANNER_REGEX_CHARS) . $followed;
    $search_php = '\b' . $preceded_php . addcslashes($search, SCANNER_REGEX_CHARS) . $followed_php . '\b';
  }
  //Case 3:
  elseif (!$wholeword && $regex) {
    $where = $search;
    $search_db = $preceded . $search . $followed;
    $search_php = $preceded_php . $search . $followed_php;
  }
  //Case 4:
  else { //!wholeword and !regex:
    $where = $search;
    $search_db = $preceded . addcslashes($search, SCANNER_REGEX_CHARS) . $followed;
    $search_php = $preceded_php . addcslashes($search, SCANNER_REGEX_CHARS) . $followed_php;
  }

  //if terms selected, then put together extra join and where clause:
  $join = '';
  if (is_array($terms) && count($terms)) {
    $terms_where = array();
    $terms_params = array();
    foreach ($terms as $term) {
      $terms_where[] = 'tn.tid = %d';
      $terms_params[] = $term;
    }
    $join = 'INNER JOIN {taxonomy_term_node} tn ON t.nid = tn.nid';
    $where .= ' AND (' . implode(' OR ', $terms_where) . ')';
  }

  $tables_map = _scanner_get_selected_tables_map();

  foreach ( $tables_map as $map ) {
    $table = $map['table'];
    $field = $map['field'];
    $type  = $map['type'];

    $query_params = array($field, $table, $type, $field, $search_db);
    if (!empty($join)) {
      $query_params = array_merge($query_params, $terms_params);
    }

    // TODO Please convert this statement to the D7 database API syntax.
    
    $query = db_select($table, 't');
    if ($table == 'node_revision') {
        $nid = 'nid';
        $vid = 'vid';
    }
    else{
        $field = $field . '_value';
        $nid = 'entity_id';
        $vid = 'revision_id';
    }
    $query->join('node', 'n', 't.' . $vid . ' = n.vid'); //Must use vid and revision_id here.  Make sure it saves as new revision.
    if (is_array($terms) && count($terms)) {
        $db_or = db_or();
        $query->join('taxonomy_index', 'tx', 't.' . $nid . ' = tx.nid');
        foreach ($terms as $term) {
            $db_or->condition('tx.tid', $term);
        }
        $query->condition($db_or);
    }
    $query->addField('t', $field, 'content');
    $query->fields('n', array('nid', 'title'));
    $query->condition('n.type', $type, '=');
    if ($mode) {
        $query->condition('t.' . $field, $search_db, 'REGEXP BINARY');
    }
    else{
        $query->condition('t.' . $field, $search_db, 'REGEXP');    
    }
    if ($published) {
        $query->condition('n.status', '1', '=');
    }
    $result = $query->execute();

    $shutting_down = FALSE;
    
    foreach ($result as $row) {
      $content = $row->content;
      $matches = array();
      $text = '';
      
      // checking for possible timeout
      // if within 5 seconds of timeout - attempt to expand environment

      
      if (REQUEST_TIME >= ($start_time + $max_execution_time - 5)) {
        if (!$expanded) {
          if ($user->uid > 0) {
            $verbose = TRUE;
          }
          else {
            $verbose = FALSE;
          }
          if (_scanner_change_env('max_execution_time', '600', $verbose)) {
            drupal_set_message(t('Default max_execution_time too small and changed to 10 minutes.'), 'error');
            $max_execution_time = 600;
          }
          $expanded = TRUE;
        }
        // if expanded environment still running out of time - shutdown process
        else {
          $shutting_down = TRUE;
          variable_set('scanner_partially_processed_' . $user->uid, $processed);
          variable_set('scanner_partial_undo_' . $user->uid, $undo_data);
          if ($searchtype == 'search') {
            drupal_set_message(t('Did not have enough time to complete search.'), 'error');
          }
          else {
            drupal_set_message(t('Did not have enough time to complete. Please re-submit replace'), 'error');
          }
          break 2;
        }
      }

      /*
       * SEARCH
       */
      if ($searchtype == 'search') {
        //pull out the terms and highlight them for display in search results:
        $regexstr = "/(.{0,130}?)($search_php)(.{0,130})/$flag";
        $hits = preg_match_all($regexstr, $content, $matches, PREG_SET_ORDER);
        if ($hits > 0) {
          foreach ( $matches as $match ) {
            if ( $match[1] ) {
              $text .= '...' . htmlentities($match[1], ENT_COMPAT, 'UTF-8');
            }
            $text .= '<strong>' . htmlentities($match[2], ENT_COMPAT, 'UTF-8') . '</strong>';
            if ( $match[3] ) {
              $text .= htmlentities($match[3], ENT_COMPAT, 'UTF-8') . '...';
            }
          }
        }
        else {
          $text = "<div class='warning'>" . t("Can't display search result due to conflict between search term and internal preg_match_all function.") . '</div>';
        }

        $results[] = array(
          'title' => $row->title,
          'type' => $type,