search.module

<?php
/**
 * @file
 * Enables site-wide keyword searching.
 */

/**
 * Matches all 'N' Unicode character classes (numbers)
 */
// cspell:disable
define('PREG_CLASS_NUMBERS',
  '\x{30}-\x{39}\x{b2}\x{b3}\x{b9}\x{bc}-\x{be}\x{660}-\x{669}\x{6f0}-\x{6f9}' .
  '\x{966}-\x{96f}\x{9e6}-\x{9ef}\x{9f4}-\x{9f9}\x{a66}-\x{a6f}\x{ae6}-\x{aef}' .
  '\x{b66}-\x{b6f}\x{be7}-\x{bf2}\x{c66}-\x{c6f}\x{ce6}-\x{cef}\x{d66}-\x{d6f}' .
  '\x{e50}-\x{e59}\x{ed0}-\x{ed9}\x{f20}-\x{f33}\x{1040}-\x{1049}\x{1369}-' .
  '\x{137c}\x{16ee}-\x{16f0}\x{17e0}-\x{17e9}\x{17f0}-\x{17f9}\x{1810}-\x{1819}' .
  '\x{1946}-\x{194f}\x{2070}\x{2074}-\x{2079}\x{2080}-\x{2089}\x{2153}-\x{2183}' .
  '\x{2460}-\x{249b}\x{24ea}-\x{24ff}\x{2776}-\x{2793}\x{3007}\x{3021}-\x{3029}' .
  '\x{3038}-\x{303a}\x{3192}-\x{3195}\x{3220}-\x{3229}\x{3251}-\x{325f}\x{3280}-' .
  '\x{3289}\x{32b1}-\x{32bf}\x{ff10}-\x{ff19}');
  // cspell:enable

/**
 * Matches all 'P' Unicode character classes (punctuation)
 */
// cspell:disable
define('PREG_CLASS_PUNCTUATION',
  '\x{21}-\x{23}\x{25}-\x{2a}\x{2c}-\x{2f}\x{3a}\x{3b}\x{3f}\x{40}\x{5b}-\x{5d}' .
  '\x{5f}\x{7b}\x{7d}\x{a1}\x{ab}\x{b7}\x{bb}\x{bf}\x{37e}\x{387}\x{55a}-\x{55f}' .
  '\x{589}\x{58a}\x{5be}\x{5c0}\x{5c3}\x{5f3}\x{5f4}\x{60c}\x{60d}\x{61b}\x{61f}' .
  '\x{66a}-\x{66d}\x{6d4}\x{700}-\x{70d}\x{964}\x{965}\x{970}\x{df4}\x{e4f}' .
  '\x{e5a}\x{e5b}\x{f04}-\x{f12}\x{f3a}-\x{f3d}\x{f85}\x{104a}-\x{104f}\x{10fb}' .
  '\x{1361}-\x{1368}\x{166d}\x{166e}\x{169b}\x{169c}\x{16eb}-\x{16ed}\x{1735}' .
  '\x{1736}\x{17d4}-\x{17d6}\x{17d8}-\x{17da}\x{1800}-\x{180a}\x{1944}\x{1945}' .
  '\x{2010}-\x{2027}\x{2030}-\x{2043}\x{2045}-\x{2051}\x{2053}\x{2054}\x{2057}' .
  '\x{207d}\x{207e}\x{208d}\x{208e}\x{2329}\x{232a}\x{23b4}-\x{23b6}\x{2768}-' .
  '\x{2775}\x{27e6}-\x{27eb}\x{2983}-\x{2998}\x{29d8}-\x{29db}\x{29fc}\x{29fd}' .
  '\x{3001}-\x{3003}\x{3008}-\x{3011}\x{3014}-\x{301f}\x{3030}\x{303d}\x{30a0}' .
  '\x{30fb}\x{fd3e}\x{fd3f}\x{fe30}-\x{fe52}\x{fe54}-\x{fe61}\x{fe63}\x{fe68}' .
  '\x{fe6a}\x{fe6b}\x{ff01}-\x{ff03}\x{ff05}-\x{ff0a}\x{ff0c}-\x{ff0f}\x{ff1a}' .
  '\x{ff1b}\x{ff1f}\x{ff20}\x{ff3b}-\x{ff3d}\x{ff3f}\x{ff5b}\x{ff5d}\x{ff5f}-' .
  '\x{ff65}');
  // cspell:enable

/**
 * Matches CJK (Chinese, Japanese, Korean) letter-like characters.
 *
 * This list is derived from the "East Asian Scripts" section of
 * http://www.unicode.org/charts/index.html, as well as a comment on
 * http://unicode.org/reports/tr11/tr11-11.html listing some character
 * ranges that are reserved for additional CJK ideographs.
 *
 * The character ranges do not include numbers, punctuation, or symbols, since
 * these are handled separately in search. Note that radicals and strokes are
 * considered symbols. (See
 * http://www.unicode.org/Public/UNIDATA/extracted/DerivedGeneralCategory.txt)
 *
 * @see search_expand_cjk()
 */
// cspell:disable
define('PREG_CLASS_CJK', '\x{1100}-\x{11FF}\x{3040}-\x{309F}\x{30A1}-\x{318E}' .
  '\x{31A0}-\x{31B7}\x{31F0}-\x{31FF}\x{3400}-\x{4DBF}\x{4E00}-\x{9FCF}' .
  '\x{A000}-\x{A48F}\x{A4D0}-\x{A4FD}\x{A960}-\x{A97F}\x{AC00}-\x{D7FF}' .
  '\x{F900}-\x{FAFF}\x{FF21}-\x{FF3A}\x{FF41}-\x{FF5A}\x{FF66}-\x{FFDC}' .
  '\x{20000}-\x{2FFFD}\x{30000}-\x{3FFFD}');
  // cspell:enable

/**
 * Implements hook_theme().
 */
function search_theme() {
  return array(
    'search_results' => array(
      'variables' => array('results' => NULL, 'module' => NULL),
      'file' => 'search.pages.inc',
      'template' => 'templates/search-results',
      'file' => 'search.theme.inc',
    ),
  );
}

/**
 * Implements hook_permission().
 */
function search_permission() {
  return array(
    'administer search' => array(
      'title' => t('Administer search'),
    ),
    'search content' => array(
      'title' => t('Use search'),
    ),
    'use advanced search' => array(
      'title' => t('Use advanced search'),
    ),
  );
}

/**
 * Implements hook_views_api().
 */
function search_views_api() {
  return array(
    'api' => '3.0',
    'path' => backdrop_get_path('module', 'search') . '/views',
  );
}

/**
 * Implements hook_block_info().
 */
function search_block_info() {
  $blocks['form'] = array(
    'info' => t('Search form'),
    'description' => t('The search form for searching site content.'),
  );
  return $blocks;
}

/**
 * Implements hook_block_configure().
 */
function search_block_configure($delta = '', $settings = array()) {
  $form = array();
  if ($delta == 'form') {
    $search_settings = !empty($settings['search'])? $settings['search'] : array();
    $search_settings += array(
      'label' => '',
      'label_hide' => FALSE,
      'placeholder' => '',
      'button_text' => 'Search',
    );

    $form['search'] = array(
      '#type' => 'fieldset',
      '#title' => t('Search form settings'),
      '#collapsible' => TRUE,
    );

    $form['search']['label'] = array(
      '#type' => 'textfield',
      '#title' => t('Search box label'),
      '#default_value' => check_plain($search_settings['label']),
    );
    $form['search']['label_hide'] = array(
      '#type' => 'checkbox',
      '#title' => t('Hide the search box label'),
      '#default_value' => $search_settings['label_hide'],
    );
    $form['search']['placeholder'] = array(
      '#type' => 'textfield',
      '#title' => t('Placeholder text'),
      '#default_value' => check_plain(trim($search_settings['placeholder'])),
      '#description' => t('This text will appear in the search box until text is entered.'),
    );
    $form['search']['button_text'] = array(
      '#type' => 'textfield',
      '#title' => t('Button text'),
      '#default_value' => check_plain(trim($search_settings['button_text'])),
      '#description' => t('Leave this field empty to hide the submit button.'),
    );
  }
  return $form;
}

/**
 * Implements hook_block_view().
 */
function search_block_view($delta = '', $settings = array(), $contexts = array()) {
  if (user_access('search content')) {
    $search_settings = !empty($settings['search'])? $settings['search'] : array();
    $search_settings += array(
      'label' => '',
      'label_hide' => TRUE,
      'placeholder' => '',
      'button_text' => 'Search',
    );
    $form = backdrop_get_form('search_block_form');

    // Show the label.
    if (!$search_settings['label_hide']) {
      $form['search_block_form']['#title_display'] = 'before';

      // Update the label text.
      if ($search_settings['label'] != '') {
        $form['search_block_form']['#title'] = t(check_plain($search_settings['label']));
      }
    }

    // Add a placeholder.
    if ($search_settings['placeholder'] != '') {
      $form['search_block_form']['#attributes']['placeholder'] = t(trim($search_settings['placeholder']));
    }

    // Change the button text.
    if ($search_settings['button_text'] != 'Search') {
      if ($search_settings['button_text'] == '') {
        $form['actions']['submit']['#access'] = FALSE;
      }
      else {
        $form['actions']['submit']['#value'] = t(check_plain(trim($search_settings['button_text'])));
      }
    }

    $block['subject'] = t('Search');
    $block['content'] = $form;

    return $block;
  }
}

/**
 * Implements hook_preprocess_block().
 */
function search_preprocess_block(&$variables) {
  if ($variables['block']->module == 'search' && $variables['block']->delta == 'form') {
    $variables['attributes']['role'] = 'search';
    $variables['content_attributes']['class'][] = 'container-inline';
  }
}

/**
 * Implements hook_menu().
 */
function search_menu() {
  $items['search'] = array(
    'title' => 'Search',
    'page callback' => 'search_view',
    'access callback' => 'search_is_active',
    'type' => MENU_SUGGESTED_ITEM,
    'file' => 'search.pages.inc',
  );
  $items['admin/config/search/settings'] = array(
    'title' => 'Search settings',
    'description' => 'Configure relevance settings for search and other indexing options.',
    'page callback' => 'backdrop_get_form',
    'page arguments' => array('search_admin_settings'),
    'access arguments' => array('administer search'),
    'weight' => -10,
    'file' => 'search.admin.inc',
  );
  $items['admin/config/search/settings/reindex'] = array(
    'title' => 'Rebuild search index',
    'page callback' => 'backdrop_get_form',
    'page arguments' => array('search_reindex_confirm'),
    'access arguments' => array('administer search'),
    'type' => MENU_VISIBLE_IN_BREADCRUMB,
    'file' => 'search.admin.inc',
  );

  // Add paths for searching. We add each module search path twice: once without
  // and once with %menu_tail appended. The reason for this is that we want to
  // preserve keywords when switching tabs, and also to have search tabs
  // highlighted properly. The only way to do that within the Backdrop menu
  // system appears to be having two sets of tabs. See discussion on issue
  // http://drupal.org/node/245103 for details.

  backdrop_static_reset('search_get_info');
  $default_info = search_get_default_module_info();
  if ($default_info) {
    foreach (search_get_info() as $module => $search_info) {
      $path = 'search/' . $search_info['path'];
      $items[$path] = array(
        'title' => $search_info['title'],
        'page callback' => 'search_view',
        'page arguments' => array($module, ''),
        'access callback' => '_search_menu_access',
        'access arguments' => array($module),
        'type' => MENU_LOCAL_TASK,
        'file' => 'search.pages.inc',
        'weight' => $module == $default_info['module'] ? -10 : 0,
        'menu_name' => 'internal',
      );
      $items["$path/%menu_tail"] = array(
        'title' => $search_info['title'],
        'load arguments' => array('%map', '%index'),
        'page callback' => 'search_view',
        'page arguments' => array($module, 2),
        'access callback' => '_search_menu_access',
        'access arguments' => array($module),
        // The default local task points to its parent, but this item points to
        // where it should so it should not be changed.
        'type' => MENU_LOCAL_TASK,
        'file' => 'search.pages.inc',
        'weight' => 0,
        // These tabs are not subtabs.
        'tab_root' => 'search/' . $default_info['path'] . '/%',
        // These tabs need to display at the same level.
        'tab_parent' => 'search/' . $default_info['path'],
        'menu_name' => 'internal',
      );
    }
  }
  return $items;
}

/**
 * Determines access for the ?q=search path.
 */
function search_is_active() {
  // This path cannot be accessed if there are no active modules.
  return user_access('search content') && search_get_info();
}

/**
 * Returns information about available search modules.
 *
 * @param $all
 *   If TRUE, information about all enabled modules implementing
 *   hook_search_info() will be returned. If FALSE (default), only modules that
 *   have been set to active on the search settings page will be returned.
 *
 * @return
 *   Array of hook_search_info() return values, keyed by module name. The
 *   'title' and 'path' array elements will be set to defaults for each module
 *   if not supplied by hook_search_info(), and an additional array element of
 *   'module' will be added (set to the module name).
 */
function search_get_info($all = FALSE) {
  $search_hooks = &backdrop_static(__FUNCTION__);

  if (!isset($search_hooks)) {
    foreach (module_implements('search_info') as $module) {
      $search_hooks[$module] = call_user_func($module . '_search_info');
      // Use module name as the default value.
      $search_hooks[$module] += array('title' => $module, 'path' => $module);
      // Include the module name itself in the array.
      $search_hooks[$module]['module'] = $module;
    }
  }

  if ($all) {
    return $search_hooks;
  }

  // Return only modules that are set to active in search settings.
  return array_intersect_key($search_hooks, array_flip((array) config_get('search.settings', 'search_active_modules')));
}

/**
 * Returns information about the default search module.
 *
 * @return
 *    The search_get_info() array element for the default search module, if any.
 */
function search_get_default_module_info() {
  $info = search_get_info();
  $default = config_get('search.settings', 'search_default_module');
  if (isset($info[$default])) {
    return $info[$default];
  }
  // The variable setting does not match any active module, so just return
  // the info for the first active module (if any).
  return reset($info);
}

/**
 * Access callback for search tabs.
 */
function _search_menu_access($name) {
  return user_access('search content') && (!function_exists($name . '_search_access') || module_invoke($name, 'search_access'));
}

/**
 * Clears a part of or the entire search index.
 *
 * @param $sid
 *   (optional) The ID of the item to remove from the search index. If
 *   specified, $module must also be given. Omit both $sid and $module to clear
 *   the entire search index.
 * @param $module
 *   (optional) The machine-readable name of the module for the item to remove
 *   from the search index.
 */
function search_reindex($sid = NULL, $module = NULL, $reindex = FALSE) {
  if ($module == NULL && $sid == NULL) {
    module_invoke_all('search_reset');
  }
  else {
    db_delete('search_dataset')
      ->condition('sid', $sid)
      ->condition('type', $module)
      ->execute();
    db_delete('search_index')
      ->condition('sid', $sid)
      ->condition('type', $module)
      ->execute();
    // Don't remove links if re-indexing.
    if (!$reindex) {
      db_delete('search_node_links')
        ->condition('sid', $sid)
        ->condition('type', $module)
        ->execute();
    }
  }
}

/**
 * Marks a word as "dirty" (changed), or retrieves the list of dirty words.
 *
 * This is used during indexing (cron). Words that are dirty have outdated
 * total counts in the search_total table, and need to be recounted.
 */
function search_dirty($word = NULL) {
  $dirty = &backdrop_static(__FUNCTION__, array());
  if ($word !== NULL) {
    $dirty[$word] = TRUE;
  }
  else {
    return $dirty;
  }
}

/**
 * Implements hook_cron().
 *
 * Fires hook_update_index() in all modules and cleans up dirty words.
 *
 * @see search_dirty()
 */
function search_cron() {
  // We register a shutdown function to ensure that search_total is always up-to-date.
  backdrop_register_shutdown_function('search_update_totals');

  $search_active_modules = config_get('search.settings', 'search_active_modules');
  if (isset($search_active_modules)) {
    foreach ($search_active_modules as $module) {
      module_invoke($module, 'update_index');
    }
  }
}

/**
 * Updates the {search_total} database table.
 *
 * This function is called on shutdown to ensure that {search_total} is always
 * up to date (even if cron times out or otherwise fails).
 */
function search_update_totals() {
  // Update word IDF (Inverse Document Frequency) counts for new/changed words.
  foreach (search_dirty() as $word => $dummy) {
    // Get total count
    $total = db_query("SELECT SUM(score) FROM {search_index} WHERE word = :word", array(':word' => $word), array('target' => 'replica'))->fetchField();
    // Apply Zipf's law to equalize the probability distribution.
    $total = log10(1 + 1/(max(1, $total)));
    db_merge('search_total')
      ->key(array('word' => $word))
      ->fields(array('count' => $total))
      ->execute();
  }
  // Find words that were deleted from search_index, but are still in
  // search_total. We use a LEFT JOIN between the two tables and keep only the
  // rows which fail to join.
  $result = db_query("SELECT t.word AS realword, i.word FROM {search_total} t LEFT JOIN {search_index} i ON t.word = i.word WHERE i.word IS NULL", array(), array('target' => 'replica'));
  $or = db_or();
  foreach ($result as $word) {
    $or->condition('word', $word->realword);
  }
  if (count($or) > 0) {
    db_delete('search_total')
      ->condition($or)
      ->execute();
  }
}

/**
 * Simplifies a string according to indexing rules.
 *
 * @param $text
 *   Text to simplify.
 *
 * @return
 *   Simplified text.
 *
 * @see hook_search_preprocess()
 */
function search_simplify($text) {
  // Decode entities to UTF-8
  $text = decode_entities($text);

  // Lowercase
  $text = backdrop_strtolower($text);

  // Remove Diacritics
  include_once BACKDROP_ROOT . '/core/includes/transliteration.inc';
  $text = transliteration_remove_diacritics($text);

  // Call an external processor for word handling.
  search_invoke_preprocess($text);

  // Simple CJK handling
  if (config_get('search.settings', 'search_overlap_cjk')) {
    $text = preg_replace_callback('/[' . PREG_CLASS_CJK . ']+/u', 'search_expand_cjk', $text);
  }

  // To improve searching for numerical data such as dates, IP addresses
  // or version numbers, we consider a group of numerical characters
  // separated only by punctuation characters to be one piece.
  // This also means that searching for e.g. '20/03/1984' also returns
  // results with '20-03-1984' in them.
  // Readable regexp: ([number]+)[punctuation]+(?=[number])
  $text = preg_replace('/([' . PREG_CLASS_NUMBERS . ']+)[' . PREG_CLASS_PUNCTUATION . ']+(?=[' . PREG_CLASS_NUMBERS . '])/u', '\1', $text);

  // Multiple dot and dash groups are word boundaries and replaced with space.
  // No need to use the unicode modifier here because 0-127 ASCII characters
  // can't match higher UTF-8 characters as the leftmost bit of those are 1.
  $text = preg_replace('/[.-]{2,}/', ' ', $text);

  // The dot, underscore and dash are removed. This allows meaningful search
  // behavior with acronyms and URLs. See unicode note directly above.
  $text = preg_replace('/[._-]+/', '', $text);

  // With the exception of the rules above, we consider all punctuation,
  // marks, spacers, etc, to be a word boundary.
  $text = preg_replace('/[' . PREG_CLASS_UNICODE_WORD_BOUNDARY . ']+/u', ' ', $text);

  // Truncate everything to 50 characters.
  $words = explode(' ', $text);
  array_walk($words, '_search_index_truncate');
  $text = implode(' ', $words);

  return $text;
}

/**
 * Splits CJK (Chinese, Japanese, Korean) text into tokens.
 *
 * The Search module matches exact words, where a word is defined to be a
 * sequence of characters delimited by spaces or punctuation. CJK languages are
 * written in long strings of characters, though, not split up into words. So
 * in order to allow search matching, we split up CJK text into tokens
 * consisting of consecutive, overlapping sequences of characters whose length
 * is equal to the 'minimum_word_size' variable. This tokenizing is only done if
 * the 'overlap_cjk' variable is TRUE.
 *
 * @param $matches
 *   This function is a callback for preg_replace_callback(), which is called
 *   from search_simplify(). So, $matches is an array of regular expression
 *   matches, which means that $matches[0] contains the matched text -- a string
 *   of CJK characters to tokenize.
 *
 * @return
 *   Tokenized text, starting and ending with a space character.
 */
function search_expand_cjk($matches) {
  $min = config_get('search.settings', 'search_minimum_word_size');
  $str = $matches[0];
  $length = backdrop_strlen($str);
  // If the text is shorter than the minimum word size, don't tokenize it.
  if ($length <= $min) {
    return ' ' . $str . ' ';
  }
  $tokens = ' ';
  // Build a FIFO queue of characters.
  $chars = array();
  for ($i = 0; $i < $length; $i++) {
    // Add the next character off the beginning of the string to the queue.
    $current = backdrop_substr($str, 0, 1);
    $str = substr($str, strlen($current));
    $chars[] = $current;
    if ($i >= $min - 1) {
      // Make a token of $min characters, and add it to the token string.
      $tokens .= implode('', $chars) . ' ';
      // Shift out the first character in the queue.
      array_shift($chars);
    }
  }
  return $tokens;
}

/**
 * Simplifies and splits a string into tokens for indexing.
 */
function search_index_split($text) {
  $last = &backdrop_static(__FUNCTION__);
  $lastsplit = &backdrop_static(__FUNCTION__ . ':lastsplit');

  if ($last == $text) {
    return $lastsplit;
  }
  // Process words
  $text = search_simplify($text);
  $words = explode(' ', $text);

  // Save last keyword result
  $last = $text;
  $lastsplit = $words;

  return $words;
}

/**
 * Helper function for array_walk in search_index_split.
 */
function _search_index_truncate(&$text) {
  if (is_numeric($text)) {
    $text = ltrim($text, '0');
  }
  $text = truncate_utf8($text, 50);
}

/**
 * Invokes hook_search_preprocess() in modules.
 */
function search_invoke_preprocess(&$text) {
  foreach (module_implements('search_preprocess') as $module) {
    $text = module_invoke($module, 'search_preprocess', $text);
  }
}

/**
 * Update the full-text search index for a particular item.
 *
 * @param $sid
 *   An ID number identifying this particular item (e.g., node ID).
 * @param $module
 *   The machine-readable name of the module that this item comes from (a module
 *   that implements hook_search_info()).
 * @param $text
 *   The content of this item. Must be a piece of HTML or plain text.
 *
 * @ingroup search
 */
function search_index($sid, $module, $text) {
  $search_settings_config = config('search.settings');
  $minimum_word_size = $search_settings_config->get('search_minimum_word_size');

  // Link matching
  global $base_url;
  $node_regexp = '@href=[\'"]?(?:' . preg_quote($base_url, '@') . '/|' . preg_quote(base_path(), '@') . ')(?:\?q=)?/?((?![a-z]+:)[^\'">]+)[\'">]@i';

  // Multipliers for scores of words inside certain HTML tags. The weights are stored
  // in a variable so that modules can overwrite the default weights.
  // Note: 'a' must be included for link ranking to work.
  $tags = $search_settings_config->get('search_tag_weights');

  // Strip off all ignored tags to speed up processing, but insert space before/after
  // them to keep word boundaries.
  $text = str_replace(array('<', '>'), array(' <', '> '), $text);
  $text = strip_tags($text, '<' . implode('><', array_keys($tags)) . '>');

  // Split HTML tags from plain text.
  $split = preg_split('/\s*<([^>]+?)>\s*/', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
  // Note: PHP ensures the array consists of alternating delimiters and literals
  // and begins and ends with a literal (inserting $null as required).

  $tag = FALSE; // Odd/even counter. Tag or no tag.
  $link = FALSE; // State variable for link analyzer
  $score = 1; // Starting score per word
  $accum = ' '; // Accumulator for cleaned up data
  $tagstack = array(); // Stack with open tags
  $tagwords = 0; // Counter for consecutive words
  $focus = 1; // Focus state

  $results = array(0 => array()); // Accumulator for words for index

  foreach ($split as $value) {
    if ($tag) {
      // Increase or decrease score per word based on tag
      list($tagname) = explode(' ', $value, 2);
      $tagname = backdrop_strtolower($tagname);
      // Closing or opening tag?
      if ($tagname[0] == '/') {
        $tagname = substr($tagname, 1);
        // If we encounter unexpected tags, reset score to avoid incorrect boosting.
        if (!count($tagstack) || $tagstack[0] != $tagname) {
          $tagstack = array();
          $score = 1;
        }
        else {
          // Remove from tag stack and decrement score
          $score = max(1, $score - $tags[array_shift($tagstack)]);
        }
        if ($tagname == 'a') {
          $link = FALSE;
        }
      }
      else {
        if (isset($tagstack[0]) && $tagstack[0] == $tagname) {
          // None of the tags we look for make sense when nested identically.
          // If they are, it's probably broken HTML.
          $tagstack = array();
          $score = 1;
        }
        else {
          // Add to open tag stack and increment score
          array_unshift($tagstack, $tagname);
          $score += $tags[$tagname];
        }
        if ($tagname == 'a') {
          // Check if link points to a node on this site
          if (preg_match($node_regexp, $value, $match)) {
            $path = backdrop_get_normal_path($match[1]);
            if (preg_match('!(?:node|book)/(?:view/)?([0-9]+)!i', $path, $match)) {
              $linknid = $match[1];
              if ($linknid > 0) {
                $node = db_query('SELECT title, nid, vid FROM {node} WHERE nid = :nid', array(':nid' => $linknid), array('target' => 'replica'))->fetchObject();
                $link = TRUE;
                $linktitle = $node->title;
              }
            }
          }
        }
      }
      // A tag change occurred, reset counter.
      $tagwords = 0;
    }
    else {
      // Note: use of PREG_SPLIT_DELIM_CAPTURE above will introduce empty values
      if ($value != '') {
        if ($link) {
          // Check to see if the node link text is its URL. If so, we use the target node title instead.
          if (preg_match('!^https?://!i', $value)) {
            $value = $linktitle;
          }
        }
        $words = search_index_split($value);
        foreach ($words as $word) {
          // Add word to accumulator
          $accum .= $word . ' ';
          // Check wordlength
          if (is_numeric($word) || backdrop_strlen($word) >= $minimum_word_size) {
            // Links score mainly for the target.
            if ($link) {
              if (!isset($results[$linknid])) {
                $results[$linknid] = array();
              }
              $results[$linknid][] = $word;
              // Reduce score of the link caption in the source.
              $focus *= 0.2;
            }
            // Fall-through
            if (!isset($results[0][$word])) {
              $results[0][$word] = 0;
            }
            $results[0][$word] += $score * $focus;

            // Focus is a decaying value in terms of the amount of unique words up to this point.
            // From 100 words and more, it decays, to e.g. 0.5 at 500 words and 0.3 at 1000 words.
            $focus = min(1, .01 + 3.5 / (2 + count($results[0]) * .015));
          }
          $tagwords++;
          // Too many words inside a single tag probably mean a tag was accidentally left open.
          if (count($tagstack) && $tagwords >= 15) {
            $tagstack = array();
            $score = 1;
          }
        }
      }
    }
    $tag = !$tag;
  }

  search_reindex($sid, $module, TRUE);

  // Insert cleaned up data into dataset
  db_insert('search_dataset')
    ->fields(array(
      'sid' => $sid,
      'type' => $module,
      'data' => $accum,
      'reindex' => 0,
    ))
    ->execute();

  // Insert results into search index
  foreach ($results[0] as $word => $score) {
    // If a word already exists in the database, its score gets increased
    // appropriately. If not, we create a new record with the appropriate
    // starting score.
    db_merge('search_index')
      ->key(array(
        'word' => $word,
        'sid' => $sid,
        'type' => $module,
      ))
      ->fields(array('score' => $score))
      ->expression('score', 'score + :score', array(':score' => $score))
      ->execute();
    search_dirty($word);
  }
  unset($results[0]);

  // Get all previous links from this item.
  $result = db_query("SELECT nid, caption FROM {search_node_links} WHERE sid = :sid AND type = :type", array(
    ':sid' => $sid,
    ':type' => $module
  ), array('target' => 'replica'));
  $links = array();
  foreach ($result as $link) {
    $links[$link->nid] = $link->caption;
  }

  // Now store links to nodes.
  foreach ($results as $nid => $words) {
    $caption = implode(' ', $words);
    if (isset($links[$nid])) {
      if ($links[$nid] != $caption) {
        // Update the existing link and mark the node for reindexing.
        db_update('search_node_links')
          ->fields(array('caption' => $caption))
          ->condition('sid', $sid)
          ->condition('type', $module)
          ->condition('nid', $nid)
          ->execute();
        search_touch_node($nid);
      }
      // Unset the link to mark it as processed.
      unset($links[$nid]);
    }
    elseif ($sid != $nid || $module != 'node') {
      // Insert the existing link and mark the node for reindexing, but don't
      // reindex if this is a link in a node pointing to itself.
      db_insert('search_node_links')
        ->fields(array(
          'caption' => $caption,
          'sid' => $sid,
          'type' => $module,
          'nid' => $nid,
        ))
        ->execute();
      search_touch_node($nid);
    }
  }
  // Any left-over links in $links no longer exist. Delete them and mark the nodes for reindexing.
  foreach ($links as $nid => $caption) {
    db_delete('search_node_links')
      ->condition('sid', $sid)
      ->condition('type', $module)
      ->condition('nid', $nid)
      ->execute();
    search_touch_node($nid);
  }
}

/**
 * Changes a node's changed timestamp to 'now' to force reindexing.
 *
 * @param $nid
 *   The node ID of the node that needs reindexing.
 */
function search_touch_node($nid) {
  db_update('search_dataset')
    ->fields(array('reindex' => REQUEST_TIME))
    ->condition('type', 'node')
    ->condition('sid', $nid)
    ->execute();
}

/**
 * Implements hook_node_update_index().
 */
function search_node_update_index(Node $node) {
  // Transplant links to a node into the target node.
  $result = db_query("SELECT caption FROM {search_node_links} WHERE nid = :nid", array(':nid' => $node->nid), array('target' => 'replica'));
  $output = array();
  foreach ($result as $link) {
    $output[] = $link->caption;
  }
  if (count($output)) {
    return '<a>(' . implode(', ', $output) . ')</a>';
  }
}

/**
 * Implements hook_node_update().
 */
function search_node_update(Node $node) {
  // Reindex the node when it is updated. The node is automatically indexed
  // when it is created, by being added to the node table.
  search_touch_node($node->nid);
}

/**
 * Implements hook_comment_insert().
 */
function search_comment_insert($comment) {
  // Reindex the node when comments are added.
  search_touch_node($comment->nid);
}

/**
 * Implements hook_comment_update().
 */
function search_comment_update($comment) {
  // Reindex the node when comments are changed.
  search_touch_node($comment->nid);
}

/**
 * Implements hook_comment_delete().
 */
function search_comment_delete($comment) {
  // Reindex the node when comments are deleted.
  search_touch_node($comment->nid);
}

/**
 * Implements hook_comment_publish().
 */
function search_comment_publish($comment) {
  // Reindex the node when comments are published.
  search_touch_node($comment->nid);
}

/**
 * Implements hook_comment_unpublish().
 */
function search_comment_unpublish($comment) {
  // Reindex the node when comments are unpublished.
  search_touch_node($comment->nid);
}

/**
 * Extracts a module-specific search option from a search expression.
 *
 * Search options are added using search_expression_insert(), and retrieved
 * using search_expression_extract(). They take the form option:value, and
 * are added to the ordinary keywords in the search expression.
 *
 * @param $expression
 *   The search expression to extract from.
 * @param $option
 *   The name of the option to retrieve from the search expression.
 *
 * @return
 *   The value previously stored in the search expression for option $option,
 *   if any. Trailing spaces in values will not be included.
 */
function search_expression_extract($expression, $option) {
  if (preg_match('/(^| )' . $option . ':([^ ]*)( |$)/i', $expression, $matches)) {
    return $matches[2];
  }
}

/**
 * Adds a module-specific search option to a search expression.
 *
 * Search options are added using search_expression_insert(), and retrieved
 * using search_expression_extract(). They take the form option:value, and
 * are added to the ordinary keywords in the search expression.
 *
 * @param $expression
 *   The search expression to add to.
 * @param $option
 *   The name of the option to add to the search expression.
 * @param $value
 *   The value to add for the option. If present, it will replace any previous
 *   value added for the option. Cannot contain any spaces or | characters, as
 *   these are used as delimiters. If you want to add a blank value $option: to
 *   the search expression, pass in an empty string or a string that is composed
 *   of only spaces. To clear a previously-stored option without adding a
 *   replacement, pass in NULL for $value or omit.
 *
 * @return
 *   $expression, with any previous value for this option removed, and a new
 *   $option:$value pair added if $value was provided.
 */
function search_expression_insert($expression, $option, $value = NULL) {
  // Remove any previous values stored with $option.
  $expression = trim(preg_replace('/(^| )' . $option . ':[^ ]*/i', '', $expression));

  // Set new value, if provided.
  if (isset($value)) {
    $expression .= ' ' . $option . ':' . trim($value);
  }
  return $expression;
}

/**
 * @defgroup search Search interface
 * @{
 * The Backdrop search interface manages a global search mechanism.
 *
 * Modules may plug into this system to provide searches of different types of
 * data. Most of the system is handled by search.module, so this must be enabled
 * for all of the search features to work.
 *
 * There are three ways to interact with the search system:
 * - Specifically for searching nodes, you can implement
 *   hook_node_update_index() and hook_node_search_result(). However, note that
 *   the search system already indexes all visible output of a node; i.e.,
 *   everything displayed normally by hook_view() and hook_node_view(). This is
 *   usually sufficient. You should only use this mechanism if you want
 *   additional, non-visible data to be indexed.
 * - Implement hook_search_info(). This will create a search tab for your module
 *   on the /search page with a simple keyword search form. You will also need
 *   to implement hook_search_execute() to perform the search.
 * - Implement hook_update_index(). This allows your module to use Backdrop's
 *   HTML indexing mechanism for searching full text efficiently.
 *
 * If your module needs to provide a more complicated search form, then you need
 * to implement it yourself without hook_search_info(). In that case, you should
 * define it as a local task (tab) under the /search page (e.g.
 * /search/my_module), so that users know where to find it.
 */

/**
 * Builds a search form.
 *
 * @param $action
 *   Form action. Defaults to "search/$path", where $path is the search path
 *   associated with the module in its hook_search_info(). This will be run
 *   through url().
 * @param $keys
 *   The search string entered by the user, containing keywords for the search.
 * @param $module
 *   The search module to render the form for: a module that implements
 *   hook_search_info(). If not supplied, the default search module is used.
 * @param $prompt
 *   Label for the keywords field. Defaults to t('Enter your keywords') if NULL.
 *   Supply '' to omit.
 *
 * @return
 *   A Form API array for the search form.
 */
function search_form($form, &$form_state, $action = '', $keys = '', $module = NULL, $prompt = NULL) {
  $module_info = FALSE;
  if (!$module) {
    $module_info = search_get_default_module_info();
  }
  else {
    $info = search_get_info();
    $module_info = isset($info[$module]) ? $info[$module] : FALSE;
  }

  // Sanity check.
  if (!$module_info) {
    form_set_error(NULL, t('Search is currently disabled.'), 'error');
    return $form;
  }

  if (!$action) {
    $action = 'search/' . $module_info['path'];
  }
  if (!isset($prompt)) {
    $prompt = t('Enter your keywords');
  }

  $form['#action'] = url($action);
  // Record the $action for later use in redirecting.
  $form_state['action'] = $action;
  $form['module'] = array('#type' => 'value', '#value' => $module);
  $form['basic'] = array('#type' => 'container', '#attributes' => array('class' => array('container-inline')));

  // This field is not required because it may be populated by the advanced
  // search fields provided by other modules (such as node module).
  $form['basic']['keys'] = array(
    '#type' => 'search',
    '#title' => $prompt,
    '#default_value' => $keys,
    '#size' => $prompt ? 40 : 20,
    '#maxlength' => 255,
  );
  // processed_keys is used to coordinate keyword passing between other forms
  // that hook into the basic search form.
  $form['basic']['processed_keys'] = array('#type' => 'value', '#value' => '');
  $form['basic']['actions'] = array('#type' => 'actions');
  $form['basic']['actions']['submit'] = array('#type' => 'submit', '#value' => t('Search'));

  return $form;
}

/**
 * Form builder; Output a search form for the search block's search box.
 *
 * @ingroup forms
 * @see search_box_form_submit()
 */
function search_box($form, &$form_state, $form_id) {
  // The #required property is not set here, so that the user is taken to the
  // search page before any error is shown.
  $form[$form_id] = array(
    '#type' => 'search',
    '#title' => t('Search'),
    '#title_display' => 'invisible',
    '#size' => 15,
    '#default_value' => '',
    '#attributes' => array('title' => t('Enter the keywords you wish to search for.')),
  );
  $form['actions'] = array('#type' => 'actions');
  $form['actions']['submit'] = array('#type' => 'submit', '#value' => t('Search'));
  $form['#submit'][] = 'search_box_form_submit';

  return $form;
}

/**
 * Process a block search form submission.
 */
function search_box_form_submit($form, &$form_state) {
  // The search form relies on control of the redirect destination for its
  // functionality, so we override any static destination set in the request,
  // for example by backdrop_access_denied() or backdrop_not_found()
  // (see http://drupal.org/node/292565).
  if (isset($_GET['destination'])) {
    unset($_GET['destination']);
  }

  // Check to see if the form was submitted empty.
  // If it is empty, display an error message.
  // This method is used instead of the #required property so that the user
  // will be taken to the search page before the error is shown.
  if ($form_state['values']['search_block_form'] == '') {
    form_set_error('keys', t('Please enter some keywords.'));
  }

  $form_id = $form['form_id']['#value'];
  $info = search_get_default_module_info();
  if ($info) {
    $form_state['redirect'] = 'search/' . $info['path'] . '/' . trim($form_state['values'][$form_id]);
  }
  else {
    form_set_error(NULL, t('Search is currently disabled.'), 'error');
  }
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function search_form_layout_block_configure_form_alter(&$form, &$form_state) {
  // Only alter the search block's configure form.
  if ($form_state['block']->module == 'search' && $form_state['block']->delta == 'form') {
    // Only hide the block title when the search block is first added.
    if ($form_state['block']->is_new == TRUE) {
      $form['title_display']['title_display']['#default_value'] = 'none';
    }
  }
}

/**
 * Performs a search by calling hook_search_execute().
 *
 * @param $keys
 *   Keyword query to search on.
 * @param $module
 *   Search module to search.
 * @param $conditions
 *   Optional array of additional search conditions.
 *
 * @return
 *   Renderable array of search results. No return value if $keys are not
 *   supplied or if the given search module is not active.
 */
function search_data($keys, $module, $conditions = NULL) {
  if (module_hook($module, 'search_execute')) {
    $results = module_invoke($module, 'search_execute', $keys, $conditions);
    if (module_hook($module, 'search_page')) {
      return module_invoke($module, 'search_page', $results);
    }
    else {
      return array(
        '#theme' => 'search_results',
        '#results' => $results,
        '#module' => $module,
      );
    }
  }
}

/**
 * Returns snippets from a piece of text, with certain keywords highlighted.
 * Used for formatting search results.
 *
 * @param $keys
 *   A string containing a search query.
 *
 * @param $text
 *   The text to extract fragments from.
 *
 * @return
 *   A string containing HTML for the excerpt.
 */
function search_excerpt($keys, $text) {
  // We highlight around non-indexable or CJK characters.
  $boundary = '(?:(?<=[' . PREG_CLASS_UNICODE_WORD_BOUNDARY . PREG_CLASS_CJK . '])|(?=[' . PREG_CLASS_UNICODE_WORD_BOUNDARY . PREG_CLASS_CJK . ']))';

  // Extract positive keywords and phrases
  preg_match_all('/ ("([^"]+)"|(?!OR)([^" ]+))/', ' ' . $keys, $matches);
  $keys = array_merge($matches[2], $matches[3]);

  // Prepare text by stripping HTML tags and decoding HTML entities.
  $text = strip_tags(str_replace(array('<', '>'), array(' <', '> '), $text));
  $text = decode_entities($text);

  // Slash-escape quotes in the search keyword string.
  array_walk($keys, '_search_excerpt_replace');
  $workkeys = $keys;

  // Extract fragments around keywords.
  // First we collect ranges of text around each keyword, starting/ending
  // at spaces, trying to get to 256 characters.
  // If the sum of all fragments is too short, we look for second occurrences.
  $ranges = array();
  $included = array();
  $foundkeys = array();
  $length = 0;
  while ($length < 256 && count($workkeys)) {
    foreach ($workkeys as $k => $key) {
      if (strlen($key) == 0) {
        unset($workkeys[$k]);
        unset($keys[$k]);
        continue;
      }
      if ($length >= 256) {
        break;
      }
      // Remember occurrence of key so we can skip over it if more occurrences
      // are desired.
      if (!isset($included[$key])) {
        $included[$key] = 0;
      }
      // Locate a keyword (position $p, always >0 because $text starts with a
      // space). First try bare keyword, but if that doesn't work, try to find a
      // derived form from search_simplify().
      $p = 0;
      if (preg_match('/' . $boundary . $key . $boundary . '/iu', $text, $match, PREG_OFFSET_CAPTURE, $included[$key])) {
        $p = $match[0][1];
      }
      else {
        $info = search_simplify_excerpt_match($key, $text, $included[$key], $boundary);
        if (!empty($info) && $info['where']) {
          $p = $info['where'];
          if ($info['keyword']) {
            $foundkeys[] = $info['keyword'];
          }
        }
      }
      // Now locate a space in front (position $q) and behind it (position $s),
      // leaving about 60 characters extra before and after for context.
      // Note that a space was added to the front and end of $text above.
      if ($p) {
        if (($q = strpos(' ' . $text, ' ', max(0, $p - 61))) !== FALSE) {
          $end = substr($text . ' ', $p, 80);
          if (($s = strrpos($end, ' ')) !== FALSE) {
            // Account for the added spaces.
            $q = max($q - 1, 0);
            $s = min($s, strlen($end) - 1);
            $ranges[$q] = $p + $s;
            $length += $p + $s - $q;
            $included[$key] = $p + 1;
          }
          else {
            unset($workkeys[$k]);
          }
        }
        else {
          unset($workkeys[$k]);
        }
      }
      else {
        unset($workkeys[$k]);
      }
    }
  }

  if (count($ranges) == 0) {
    // We didn't find any keyword matches, so just return the first part of the
    // text. We also need to re-encode any HTML special characters that we
    // entity-decoded above.
    return check_plain(truncate_utf8($text, 256, TRUE, TRUE));
  }

  // Sort the text ranges by starting position.
  ksort($ranges);

  // Now we collapse overlapping text ranges into one. The sorting makes it O(n).
  $newranges = array();
  foreach ($ranges as $from2 => $to2) {
    if (!isset($from1)) {
      $from1 = $from2;
      $to1 = $to2;
      continue;
    }
    if ($from2 <= $to1) {
      $to1 = max($to1, $to2);
    }
    else {
      $newranges[$from1] = $to1;
      $from1 = $from2;
      $to1 = $to2;
    }
  }
  $newranges[$from1] = $to1;

  // Fetch text
  $out = array();
  foreach ($newranges as $from => $to) {
    $out[] = substr($text, $from, $to - $from);
  }

  // Let translators have the ... separator text as one chunk.
  $dots = explode('!excerpt', t('... !excerpt ... !excerpt ...'));

  $text = (isset($newranges[0]) ? '' : $dots[0]) . implode($dots[1], $out) . $dots[2];
  $text = check_plain($text);

  // Slash-escape quotes in keys found in a derived form and merge with original keys.
  array_walk($foundkeys, '_search_excerpt_replace');
  $keys = array_merge($keys, $foundkeys);

  // Highlight keywords. Must be done at once to prevent conflicts ('strong' and '<strong>').
  $text = preg_replace('/' . $boundary . '(' . implode('|', $keys) . ')' . $boundary . '/iu', '<strong>\0</strong>', $text);
  return $text;
}

/**
 * @} End of "defgroup search".
 */

/**
 * Helper function for array_walk() in search_excerpt().
 */
function _search_excerpt_replace(&$text) {
  $text = preg_quote($text, '/');
}

/**
 * Find words in the original text that matched via search_simplify().
 *
 * This is called in search_excerpt() if an exact match is not found in the
 * text, so that we can find the derived form that matches.
 *
 * @param $key
 *   The keyword to find.
 * @param $text
 *   The text to search for the keyword.
 * @param $offset
 *   Offset position in $text to start searching at.
 * @param $boundary
 *   Text to include in a regular expression that will match a word boundary.
 *
 * @return
 *   FALSE if no match is found. If a match is found, return an associative
 *   array with element 'where' giving the position of the match, and element
 *   'keyword' giving the actual word found in the text at that position.
 */
function search_simplify_excerpt_match($key, $text, $offset, $boundary) {
  $pos = NULL;
  $simplified_key = search_simplify($key);
  $simplified_text = search_simplify($text);

  // Return immediately if simplified key or text are empty.
  if (!$simplified_key || !$simplified_text) {
    return FALSE;
  }

  // Check if we have a match after simplification in the text.
  if (!preg_match('/' . $boundary . $simplified_key . $boundary . '/iu', $simplified_text, $match, PREG_OFFSET_CAPTURE, $offset)) {
    return FALSE;
  }

  // If we get here, we have a match. Now find the exact location of the match
  // and the original text that matched. Start by splitting up the text by all
  // potential starting points of the matching text and iterating through them.
  $split = array_filter(preg_split('/' . $boundary . '/iu', $text, -1, PREG_SPLIT_OFFSET_CAPTURE), '_search_excerpt_match_filter');
  foreach ($split as $value) {
    // Skip starting points before the offset.
    if ($value[1] < $offset) {
      continue;
    }

    // Check a window of 80 characters after the starting point for a match,
    // based on the size of the excerpt window.
    $window = substr($text, $value[1], 80);
    $simplified_window = search_simplify($window);
    if (strpos($simplified_window, $simplified_key) === 0) {
      // We have a match in this window. Store the position of the match.
      $pos = $value[1];
      // Iterate through the text in the window until we find the full original
      // matching text.
      $length = strlen($window);
      for ($i = 1; $i <= $length; $i++) {
        $keyfound = substr($text, $value[1], $i);
        if ($simplified_key == search_simplify($keyfound)) {
          break;
        }
      }
      break;
    }
  }

  return $pos ? array('where' => $pos, 'keyword' => $keyfound) : FALSE;
}

/**
 * Helper function for array_filter() in search_search_excerpt_match().
 */
function _search_excerpt_match_filter($var) {
  return strlen(trim($var[0]));
}

/**
 * Implements hook_forms().
 */
function search_forms() {
  $forms['search_block_form']= array(
    'callback' => 'search_box',
    'callback arguments' => array('search_block_form'),
  );
  return $forms;
}

/**
 * Implements hook_autoload_info().
 */
function search_autoload_info() {
  return array(
    'SearchQuery' => 'search.extender.inc',
    'viewsSearchQuery' => 'search.extender.inc',

    // Views handlers.
    'views_handler_argument_search' => 'views/views_handler_argument_search.inc',
    'views_handler_field_search_score' => 'views/views_handler_field_search_score.inc',
    'views_handler_filter_search' => 'views/views_handler_filter_search.inc',
    'views_handler_sort_search_score' => 'views/views_handler_sort_search_score.inc',
    'views_plugin_row_search_view' => 'views/views_plugin_row_search_view.inc',
  );
}

/**
 * Implements hook_config_info().
 */
function search_config_info() {
  $prefixes['search.settings'] = array(
    'label' => t('Search settings'),
    'group' => t('Configuration'),
  );
  return $prefixes;
}

/**
 * Gets stats for total and remaining items to be indexed.
 *
 * @param array $modules
 *  An array of module names whose index stats we are getting.
 *
 * @return array
 *  An array with the following keys:
 *  - remaining: The number of remaining items to be indexed.
 *  - total: The total number of indexable items.
 */
function search_get_stats($modules = array()) {
  if (empty($module)) {
    $modules = config_get('search.settings', 'search_active_modules');
  }
  $remaining = 0;
  $total = 0;
  foreach ($modules as $module) {
    if ($status = module_invoke($module, 'search_status')) {
      $remaining += $status['remaining'];
      $total += $status['total'];
    }
  }

  return array(
    'remaining' => $remaining,
    'total' => $total,
  );
}

/**
 * Batch operation to rebuild the search index.
 *
 * @see search_reindex_confirm()
 * @see search_reindex_confirm_submit()
 */
function search_reindex_batch($passes_needed, $search_active_modules, &$context) {
  if (!isset($context['sandbox']['current_pass'])) {
    $context['sandbox']['current_pass'] = 0;
  }

  // Invoke hook_update_index for all search active modules.
  if ($context['sandbox']['current_pass'] < $passes_needed) {
    // Register a shutdown function to ensure that search_total is up-to-date.
    backdrop_register_shutdown_function('search_update_totals');
    foreach ($search_active_modules as $module) {
      module_invoke($module, 'update_index');
    }
    $context['sandbox']['current_pass']++;
    $context['message'] = t('Now processing pass %pass of %needed', array('%pass' => $context['sandbox']['current_pass'], '%needed' => $passes_needed));
    $context['finished'] = $context['sandbox']['current_pass'] / $passes_needed;
  }
}

/**
 * Batch 'finished' callback for rebuilding the search index.
 *
 * @see search_reindex_batch()
 */
function search_reindex_batch_finished($success, $results, $operations) {
  if ($success) {
    $config = config('search.settings');
    // Collect some stats
    $remaining = 0;
    $total = 0;
    foreach ($config->get('search_active_modules') as $module) {
      if ($status = module_invoke($module, 'search_status')) {
        $remaining += $status['remaining'];
        $total += $status['total'];
      }
    }
    $count = format_plural($remaining, 'There is 1 item left to index.', 'There are @count items left to index.');
    $percentage = ((int)min(100, 100 * ($total - $remaining) / max(1, $total))) . '%';
    $message = '<p><strong>' . t('%percentage of the site has been indexed.', array('%percentage' => $percentage)) . ' ' . $count . '</strong></p>';
    backdrop_set_message($message);
  }
  else {
    // An error occurred.
    $error_operation = reset($operations);
    backdrop_set_message(
      t('An error occurred while processing @operation with arguments : @args',
        array(
          '@operation' => $error_operation[0],
          '@args' => print_r($error_operation[0], TRUE),
        )
      )
    );
  }
}