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Source: /modules/search/search.module - 1356 lines - 51148 bytes - Summary - Text - Print

   1  <?php
   2  
   3  /**
   4   * @file
   5   * Enables site-wide keyword searching.
   6   */
   7  
   8  /**
   9   * Matches all 'N' Unicode character classes (numbers)
  10   */
  11  define('PREG_CLASS_NUMBERS',
  12    '\x{30}-\x{39}\x{b2}\x{b3}\x{b9}\x{bc}-\x{be}\x{660}-\x{669}\x{6f0}-\x{6f9}' .
  13    '\x{966}-\x{96f}\x{9e6}-\x{9ef}\x{9f4}-\x{9f9}\x{a66}-\x{a6f}\x{ae6}-\x{aef}' .
  14    '\x{b66}-\x{b6f}\x{be7}-\x{bf2}\x{c66}-\x{c6f}\x{ce6}-\x{cef}\x{d66}-\x{d6f}' .
  15    '\x{e50}-\x{e59}\x{ed0}-\x{ed9}\x{f20}-\x{f33}\x{1040}-\x{1049}\x{1369}-' .
  16    '\x{137c}\x{16ee}-\x{16f0}\x{17e0}-\x{17e9}\x{17f0}-\x{17f9}\x{1810}-\x{1819}' .
  17    '\x{1946}-\x{194f}\x{2070}\x{2074}-\x{2079}\x{2080}-\x{2089}\x{2153}-\x{2183}' .
  18    '\x{2460}-\x{249b}\x{24ea}-\x{24ff}\x{2776}-\x{2793}\x{3007}\x{3021}-\x{3029}' .
  19    '\x{3038}-\x{303a}\x{3192}-\x{3195}\x{3220}-\x{3229}\x{3251}-\x{325f}\x{3280}-' .
  20    '\x{3289}\x{32b1}-\x{32bf}\x{ff10}-\x{ff19}');
  21  
  22  /**
  23   * Matches all 'P' Unicode character classes (punctuation)
  24   */
  25  define('PREG_CLASS_PUNCTUATION',
  26    '\x{21}-\x{23}\x{25}-\x{2a}\x{2c}-\x{2f}\x{3a}\x{3b}\x{3f}\x{40}\x{5b}-\x{5d}' .
  27    '\x{5f}\x{7b}\x{7d}\x{a1}\x{ab}\x{b7}\x{bb}\x{bf}\x{37e}\x{387}\x{55a}-\x{55f}' .
  28    '\x{589}\x{58a}\x{5be}\x{5c0}\x{5c3}\x{5f3}\x{5f4}\x{60c}\x{60d}\x{61b}\x{61f}' .
  29    '\x{66a}-\x{66d}\x{6d4}\x{700}-\x{70d}\x{964}\x{965}\x{970}\x{df4}\x{e4f}' .
  30    '\x{e5a}\x{e5b}\x{f04}-\x{f12}\x{f3a}-\x{f3d}\x{f85}\x{104a}-\x{104f}\x{10fb}' .
  31    '\x{1361}-\x{1368}\x{166d}\x{166e}\x{169b}\x{169c}\x{16eb}-\x{16ed}\x{1735}' .
  32    '\x{1736}\x{17d4}-\x{17d6}\x{17d8}-\x{17da}\x{1800}-\x{180a}\x{1944}\x{1945}' .
  33    '\x{2010}-\x{2027}\x{2030}-\x{2043}\x{2045}-\x{2051}\x{2053}\x{2054}\x{2057}' .
  34    '\x{207d}\x{207e}\x{208d}\x{208e}\x{2329}\x{232a}\x{23b4}-\x{23b6}\x{2768}-' .
  35    '\x{2775}\x{27e6}-\x{27eb}\x{2983}-\x{2998}\x{29d8}-\x{29db}\x{29fc}\x{29fd}' .
  36    '\x{3001}-\x{3003}\x{3008}-\x{3011}\x{3014}-\x{301f}\x{3030}\x{303d}\x{30a0}' .
  37    '\x{30fb}\x{fd3e}\x{fd3f}\x{fe30}-\x{fe52}\x{fe54}-\x{fe61}\x{fe63}\x{fe68}' .
  38    '\x{fe6a}\x{fe6b}\x{ff01}-\x{ff03}\x{ff05}-\x{ff0a}\x{ff0c}-\x{ff0f}\x{ff1a}' .
  39    '\x{ff1b}\x{ff1f}\x{ff20}\x{ff3b}-\x{ff3d}\x{ff3f}\x{ff5b}\x{ff5d}\x{ff5f}-' .
  40    '\x{ff65}');
  41  
  42  /**
  43   * Matches CJK (Chinese, Japanese, Korean) letter-like characters.
  44   *
  45   * This list is derived from the "East Asian Scripts" section of
  46   * http://www.unicode.org/charts/index.html, as well as a comment on
  47   * http://unicode.org/reports/tr11/tr11-11.html listing some character
  48   * ranges that are reserved for additional CJK ideographs.
  49   *
  50   * The character ranges do not include numbers, punctuation, or symbols, since
  51   * these are handled separately in search. Note that radicals and strokes are
  52   * considered symbols. (See
  53   * http://www.unicode.org/Public/UNIDATA/extracted/DerivedGeneralCategory.txt)
  54   *
  55   * @see search_expand_cjk()
  56   */
  57  define('PREG_CLASS_CJK', '\x{1100}-\x{11FF}\x{3040}-\x{309F}\x{30A1}-\x{318E}' .
  58    '\x{31A0}-\x{31B7}\x{31F0}-\x{31FF}\x{3400}-\x{4DBF}\x{4E00}-\x{9FCF}' .
  59    '\x{A000}-\x{A48F}\x{A4D0}-\x{A4FD}\x{A960}-\x{A97F}\x{AC00}-\x{D7FF}' .
  60    '\x{F900}-\x{FAFF}\x{FF21}-\x{FF3A}\x{FF41}-\x{FF5A}\x{FF66}-\x{FFDC}' .
  61    '\x{20000}-\x{2FFFD}\x{30000}-\x{3FFFD}');
  62  
  63  /**
  64   * Implements hook_help().
  65   */
  66  function search_help($path, $arg) {
  67    switch ($path) {
  68      case 'admin/help#search':
  69        $output = '';
  70        $output .= '<h3>' . t('About') . '</h3>';
  71        $output .= '<p>' . t('The Search module provides the ability to index and search for content by exact keywords, and for users by username or e-mail. For more information, see the online handbook entry for <a href="@search-module">Search module</a>.', array('@search-module' => 'http://drupal.org/documentation/modules/search/', '@search' => url('search'))) . '</p>';
  72        $output .= '<h3>' . t('Uses') . '</h3>';
  73        $output .= '<dl>';
  74        $output .= '<dt>' . t('Searching content and users') . '</dt>';
  75        $output .= '<dd>' . t('Users with <em>Use search</em> permission can use the search block and <a href="@search">Search page</a>. Users with the <em>View published content</em> permission can search for content containing exact keywords. Users with the <em>View user profiles</em> permission can search for users containing the keyword anywhere in the user name, and users with the <em>Administer users</em> permission can search for users by email address. Additionally, users with <em>Use advanced search</em> permission can find content using more complex search methods and filtering by choosing the <em>Advanced search</em> option on the <a href="@search">Search page</a>.', array('@search' => url('search'))) . '</dd>';
  76        $output .= '<dt>' . t('Indexing content with cron') . '</dt>';
  77        $output .= '<dd>' . t('To provide keyword searching, the search engine maintains an index of words found in the content and its fields, along with text added to your content by other modules (such as comments from the core Comment module, and taxonomy terms from the core Taxonomy module). To build and maintain this index, a correctly configured <a href="@cron">cron maintenance task</a> is required. Users with <em>Administer search</em> permission can further configure the cron settings on the <a href="@searchsettings">Search settings page</a>.', array('@cron' => 'http://drupal.org/cron', '@searchsettings' => url('admin/config/search/settings'))) . '</dd>';
  78        $output .= '<dt>' . t('Content reindexing') . '</dt>';
  79        $output .= '<dd>' . t('Content-related actions on your site (creating, editing, or deleting content and comments) automatically cause affected content items to be marked for indexing or reindexing at the next cron run. When content is marked for reindexing, the previous content remains in the index until cron runs, at which time it is replaced by the new content. Unlike content-related actions, actions related to the structure of your site do not cause affected content to be marked for reindexing. Examples of structure-related actions that affect content include deleting or editing taxonomy terms, enabling or disabling modules that add text to content (such as Taxonomy, Comment, and field-providing modules), and modifying the fields or display parameters of your content types. If you take one of these actions and you want to ensure that the search index is updated to reflect your changed site structure, you can mark all content for reindexing by clicking the "Re-index site" button on the <a href="@searchsettings">Search settings page</a>. If you have a lot of content on your site, it may take several cron runs for the content to be reindexed.', array('@searchsettings' => url('admin/config/search/settings'))) . '</dd>';
  80        $output .= '<dt>' . t('Configuring search settings') . '</dt>';
  81        $output .= '<dd>' . t('Indexing behavior can be adjusted using the <a href="@searchsettings">Search settings page</a>. Users with <em>Administer search</em> permission can control settings such as the <em>Number of items to index per cron run</em>, <em>Indexing settings</em> (word length), <em>Active search modules</em>, and <em>Content ranking</em>, which lets you adjust the priority in which indexed content is returned in results.', array('@searchsettings' => url('admin/config/search/settings'))) . '</dd>';
  82        $output .= '<dt>' . t('Search block') . '</dt>';
  83        $output .= '<dd>' . t('The Search module includes a default <em>Search form</em> block, which can be enabled and configured on the <a href="@blocks">Blocks administration page</a>. The block is available to users with the <em>Search content</em> permission.', array('@blocks' => url('admin/structure/block'))) . '</dd>';
  84        $output .= '<dt>' . t('Extending Search module') . '</dt>';
  85        $output .= '<dd>' . t('By default, the Search module only supports exact keyword matching in content searches. You can modify this behavior by installing a language-specific stemming module for your language (such as <a href="http://drupal.org/project/porterstemmer">Porter Stemmer</a> for American English), which allows words such as walk, walking, and walked to be matched in the Search module. Another approach is to use a third-party search technology with stemming or partial word matching features built in, such as <a href="http://drupal.org/project/apachesolr">Apache Solr</a> or <a href="http://drupal.org/project/sphinx">Sphinx</a>. These and other <a href="@contrib-search">search-related contributed modules</a> can be downloaded by visiting Drupal.org.', array('@contrib-search' => 'http://drupal.org/project/modules?filters=tid%3A105')) . '</dd>';
  86        $output .= '</dl>';
  87        return $output;
  88      case 'admin/config/search/settings':
  89        return '<p>' . t('The search engine maintains an index of words found in your site\'s content. To build and maintain this index, a correctly configured <a href="@cron">cron maintenance task</a> is required. Indexing behavior can be adjusted using the settings below.', array('@cron' => url('admin/reports/status'))) . '</p>';
  90      case 'search#noresults':
  91        return t('<ul>
  92  <li>Check if your spelling is correct.</li>
  93  <li>Remove quotes around phrases to search for each word individually. <em>bike shed</em> will often show more results than <em>&quot;bike shed&quot;</em>.</li>
  94  <li>Consider loosening your query with <em>OR</em>. <em>bike OR shed</em> will often show more results than <em>bike shed</em>.</li>
  95  </ul>');
  96    }
  97  }
  98  
  99  /**
 100   * Implements hook_theme().
 101   */
 102  function search_theme() {
 103    return array(
 104      'search_block_form' => array(
 105        'render element' => 'form',
 106        'template' => 'search-block-form',
 107      ),
 108      'search_result' => array(
 109        'variables' => array('result' => NULL, 'module' => NULL),
 110        'file' => 'search.pages.inc',
 111        'template' => 'search-result',
 112      ),
 113      'search_results' => array(
 114        'variables' => array('results' => NULL, 'module' => NULL),
 115        'file' => 'search.pages.inc',
 116        'template' => 'search-results',
 117      ),
 118    );
 119  }
 120  
 121  /**
 122   * Implements hook_permission().
 123   */
 124  function search_permission() {
 125    return array(
 126      'administer search' => array(
 127        'title' => t('Administer search'),
 128      ),
 129      'search content' => array(
 130        'title' => t('Use search'),
 131      ),
 132      'use advanced search' => array(
 133        'title' => t('Use advanced search'),
 134      ),
 135    );
 136  }
 137  
 138  /**
 139   * Implements hook_block_info().
 140   */
 141  function search_block_info() {
 142    $blocks['form']['info'] = t('Search form');
 143    // Not worth caching.
 144    $blocks['form']['cache'] = DRUPAL_NO_CACHE;
 145    $blocks['form']['properties']['administrative'] = TRUE;
 146    return $blocks;
 147  }
 148  
 149  /**
 150   * Implements hook_block_view().
 151   */
 152  function search_block_view($delta = '') {
 153    if (user_access('search content')) {
 154      $block['content'] = drupal_get_form('search_block_form');
 155      return $block;
 156    }
 157  }
 158  
 159  /**
 160   * Implements hook_menu().
 161   */
 162  function search_menu() {
 163    $items['search'] = array(
 164      'title' => 'Search',
 165      'page callback' => 'search_view',
 166      'access callback' => 'search_is_active',
 167      'type' => MENU_SUGGESTED_ITEM,
 168      'file' => 'search.pages.inc',
 169    );
 170    $items['admin/config/search/settings'] = array(
 171      'title' => 'Search settings',
 172      'description' => 'Configure relevance settings for search and other indexing options.',
 173      'page callback' => 'drupal_get_form',
 174      'page arguments' => array('search_admin_settings'),
 175      'access arguments' => array('administer search'),
 176      'weight' => -10,
 177      'file' => 'search.admin.inc',
 178    );
 179    $items['admin/config/search/settings/reindex'] = array(
 180      'title' => 'Clear index',
 181      'page callback' => 'drupal_get_form',
 182      'page arguments' => array('search_reindex_confirm'),
 183      'access arguments' => array('administer search'),
 184      'type' => MENU_VISIBLE_IN_BREADCRUMB,
 185      'file' => 'search.admin.inc',
 186    );
 187  
 188    // Add paths for searching. We add each module search path twice: once without
 189    // and once with %menu_tail appended. The reason for this is that we want to
 190    // preserve keywords when switching tabs, and also to have search tabs
 191    // highlighted properly. The only way to do that within the Drupal menu
 192    // system appears to be having two sets of tabs. See discussion on issue
 193    // http://drupal.org/node/245103 for details.
 194  
 195    drupal_static_reset('search_get_info');
 196    $default_info = search_get_default_module_info();
 197    if ($default_info) {
 198      foreach (search_get_info() as $module => $search_info) {
 199        $path = 'search/' . $search_info['path'];
 200        $items[$path] = array(
 201          'title' => $search_info['title'],
 202          'page callback' => 'search_view',
 203          'page arguments' => array($module, ''),
 204          'access callback' => '_search_menu_access',
 205          'access arguments' => array($module),
 206          'type' => MENU_LOCAL_TASK,
 207          'file' => 'search.pages.inc',
 208          'weight' => $module == $default_info['module'] ? -10 : 0,
 209        );
 210        $items["$path/%menu_tail"] = array(
 211          'title' => $search_info['title'],
 212          'load arguments' => array('%map', '%index'),
 213          'page callback' => 'search_view',
 214          'page arguments' => array($module, 2),
 215          'access callback' => '_search_menu_access',
 216          'access arguments' => array($module),
 217          // The default local task points to its parent, but this item points to
 218          // where it should so it should not be changed.
 219          'type' => MENU_LOCAL_TASK,
 220          'file' => 'search.pages.inc',
 221          'weight' => 0,
 222          // These tabs are not subtabs.
 223          'tab_root' => 'search/' . $default_info['path'] . '/%',
 224          // These tabs need to display at the same level.
 225          'tab_parent' => 'search/' . $default_info['path'],
 226        );
 227      }
 228    }
 229    return $items;
 230  }
 231  
 232  /**
 233   * Determines access for the ?q=search path.
 234   */
 235  function search_is_active() {
 236    // This path cannot be accessed if there are no active modules.
 237    return user_access('search content') && search_get_info();
 238  }
 239  
 240  /**
 241   * Returns information about available search modules.
 242   *
 243   * @param $all
 244   *   If TRUE, information about all enabled modules implementing
 245   *   hook_search_info() will be returned. If FALSE (default), only modules that
 246   *   have been set to active on the search settings page will be returned.
 247   *
 248   * @return
 249   *   Array of hook_search_info() return values, keyed by module name. The
 250   *   'title' and 'path' array elements will be set to defaults for each module
 251   *   if not supplied by hook_search_info(), and an additional array element of
 252   *   'module' will be added (set to the module name).
 253   */
 254  function search_get_info($all = FALSE) {
 255    $search_hooks = &drupal_static(__FUNCTION__);
 256  
 257    if (!isset($search_hooks)) {
 258      foreach (module_implements('search_info') as $module) {
 259        $search_hooks[$module] = call_user_func($module . '_search_info');
 260        // Use module name as the default value.
 261        $search_hooks[$module] += array('title' => $module, 'path' => $module);
 262        // Include the module name itself in the array.
 263        $search_hooks[$module]['module'] = $module;
 264      }
 265    }
 266  
 267    if ($all) {
 268      return $search_hooks;
 269    }
 270  
 271    $active = variable_get('search_active_modules', array('node', 'user'));
 272    return array_intersect_key($search_hooks, array_flip($active));
 273  }
 274  
 275  /**
 276   * Returns information about the default search module.
 277   *
 278   * @return
 279   *    The search_get_info() array element for the default search module, if any.
 280   */
 281  function search_get_default_module_info() {
 282    $info = search_get_info();
 283    $default = variable_get('search_default_module', 'node');
 284    if (isset($info[$default])) {
 285      return $info[$default];
 286    }
 287    // The variable setting does not match any active module, so just return
 288    // the info for the first active module (if any).
 289    return reset($info);
 290  }
 291  
 292  /**
 293   * Access callback for search tabs.
 294   */
 295  function _search_menu_access($name) {
 296    return user_access('search content') && (!function_exists($name . '_search_access') || module_invoke($name, 'search_access'));
 297  }
 298  
 299  /**
 300   * Clears a part of or the entire search index.
 301   *
 302   * @param $sid
 303   *   (optional) The ID of the item to remove from the search index. If
 304   *   specified, $module must also be given. Omit both $sid and $module to clear
 305   *   the entire search index.
 306   * @param $module
 307   *   (optional) The machine-readable name of the module for the item to remove
 308   *   from the search index.
 309   */
 310  function search_reindex($sid = NULL, $module = NULL, $reindex = FALSE) {
 311    if ($module == NULL && $sid == NULL) {
 312      module_invoke_all('search_reset');
 313    }
 314    else {
 315      db_delete('search_dataset')
 316        ->condition('sid', $sid)
 317        ->condition('type', $module)
 318        ->execute();
 319      db_delete('search_index')
 320        ->condition('sid', $sid)
 321        ->condition('type', $module)
 322        ->execute();
 323      // Don't remove links if re-indexing.
 324      if (!$reindex) {
 325        db_delete('search_node_links')
 326          ->condition('sid', $sid)
 327          ->condition('type', $module)
 328          ->execute();
 329      }
 330    }
 331  }
 332  
 333  /**
 334   * Marks a word as "dirty" (changed), or retrieves the list of dirty words.
 335   *
 336   * This is used during indexing (cron). Words that are dirty have outdated
 337   * total counts in the search_total table, and need to be recounted.
 338   */
 339  function search_dirty($word = NULL) {
 340    $dirty = &drupal_static(__FUNCTION__, array());
 341    if ($word !== NULL) {
 342      $dirty[$word] = TRUE;
 343    }
 344    else {
 345      return $dirty;
 346    }
 347  }
 348  
 349  /**
 350   * Implements hook_cron().
 351   *
 352   * Fires hook_update_index() in all modules and cleans up dirty words.
 353   *
 354   * @see search_dirty()
 355   */
 356  function search_cron() {
 357    // We register a shutdown function to ensure that search_total is always up
 358    // to date.
 359    drupal_register_shutdown_function('search_update_totals');
 360  
 361    foreach (variable_get('search_active_modules', array('node', 'user')) as $module) {
 362      // Update word index
 363      module_invoke($module, 'update_index');
 364    }
 365  }
 366  
 367  /**
 368   * Updates the {search_total} database table.
 369   *
 370   * This function is called on shutdown to ensure that {search_total} is always
 371   * up to date (even if cron times out or otherwise fails).
 372   */
 373  function search_update_totals() {
 374    // Update word IDF (Inverse Document Frequency) counts for new/changed words.
 375    foreach (search_dirty() as $word => $dummy) {
 376      // Get total count
 377      $total = db_query("SELECT SUM(score) FROM {search_index} WHERE word = :word", array(':word' => $word), array('target' => 'slave'))->fetchField();
 378      // Apply Zipf's law to equalize the probability distribution.
 379      $total = log10(1 + 1/(max(1, $total)));
 380      db_merge('search_total')
 381        ->key(array('word' => $word))
 382        ->fields(array('count' => $total))
 383        ->execute();
 384    }
 385    // Find words that were deleted from search_index, but are still in
 386    // search_total. We use a LEFT JOIN between the two tables and keep only the
 387    // rows which fail to join.
 388    $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' => 'slave'));
 389    $or = db_or();
 390    foreach ($result as $word) {
 391      $or->condition('word', $word->realword);
 392    }
 393    if (count($or) > 0) {
 394      db_delete('search_total')
 395        ->condition($or)
 396        ->execute();
 397    }
 398  }
 399  
 400  /**
 401   * Simplifies a string according to indexing rules.
 402   *
 403   * @param $text
 404   *   Text to simplify.
 405   *
 406   * @return
 407   *   Simplified text.
 408   *
 409   * @see hook_search_preprocess()
 410   */
 411  function search_simplify($text) {
 412    // Decode entities to UTF-8
 413    $text = decode_entities($text);
 414  
 415    // Lowercase
 416    $text = drupal_strtolower($text);
 417  
 418    // Call an external processor for word handling.
 419    search_invoke_preprocess($text);
 420  
 421    // Simple CJK handling
 422    if (variable_get('overlap_cjk', TRUE)) {
 423      $text = preg_replace_callback('/[' . PREG_CLASS_CJK . ']+/u', 'search_expand_cjk', $text);
 424    }
 425  
 426    // To improve searching for numerical data such as dates, IP addresses
 427    // or version numbers, we consider a group of numerical characters
 428    // separated only by punctuation characters to be one piece.
 429    // This also means that searching for e.g. '20/03/1984' also returns
 430    // results with '20-03-1984' in them.
 431    // Readable regexp: ([number]+)[punctuation]+(?=[number])
 432    $text = preg_replace('/([' . PREG_CLASS_NUMBERS . ']+)[' . PREG_CLASS_PUNCTUATION . ']+(?=[' . PREG_CLASS_NUMBERS . '])/u', '\1', $text);
 433  
 434    // Multiple dot and dash groups are word boundaries and replaced with space.
 435    // No need to use the unicode modifer here because 0-127 ASCII characters
 436    // can't match higher UTF-8 characters as the leftmost bit of those are 1.
 437    $text = preg_replace('/[.-]{2,}/', ' ', $text);
 438  
 439    // The dot, underscore and dash are simply removed. This allows meaningful
 440    // search behavior with acronyms and URLs. See unicode note directly above.
 441    $text = preg_replace('/[._-]+/', '', $text);
 442  
 443    // With the exception of the rules above, we consider all punctuation,
 444    // marks, spacers, etc, to be a word boundary.
 445    $text = preg_replace('/[' . PREG_CLASS_UNICODE_WORD_BOUNDARY . ']+/u', ' ', $text);
 446  
 447    // Truncate everything to 50 characters.
 448    $words = explode(' ', $text);
 449    array_walk($words, '_search_index_truncate');
 450    $text = implode(' ', $words);
 451  
 452    return $text;
 453  }
 454  
 455  /**
 456   * Splits CJK (Chinese, Japanese, Korean) text into tokens.
 457   *
 458   * The Search module matches exact words, where a word is defined to be a
 459   * sequence of characters delimited by spaces or punctuation. CJK languages are
 460   * written in long strings of characters, though, not split up into words. So
 461   * in order to allow search matching, we split up CJK text into tokens
 462   * consisting of consecutive, overlapping sequences of characters whose length
 463   * is equal to the 'minimum_word_size' variable. This tokenizing is only done if
 464   * the 'overlap_cjk' variable is TRUE.
 465   *
 466   * @param $matches
 467   *   This function is a callback for preg_replace_callback(), which is called
 468   *   from search_simplify(). So, $matches is an array of regular expression
 469   *   matches, which means that $matches[0] contains the matched text -- a string
 470   *   of CJK characters to tokenize.
 471   *
 472   * @return
 473   *   Tokenized text, starting and ending with a space character.
 474   */
 475  function search_expand_cjk($matches) {
 476    $min = variable_get('minimum_word_size', 3);
 477    $str = $matches[0];
 478    $length = drupal_strlen($str);
 479    // If the text is shorter than the minimum word size, don't tokenize it.
 480    if ($length <= $min) {
 481      return ' ' . $str . ' ';
 482    }
 483    $tokens = ' ';
 484    // Build a FIFO queue of characters.
 485    $chars = array();
 486    for ($i = 0; $i < $length; $i++) {
 487      // Add the next character off the beginning of the string to the queue.
 488      $current = drupal_substr($str, 0, 1);
 489      $str = substr($str, strlen($current));
 490      $chars[] = $current;
 491      if ($i >= $min - 1) {
 492        // Make a token of $min characters, and add it to the token string.
 493        $tokens .= implode('', $chars) . ' ';
 494        // Shift out the first character in the queue.
 495        array_shift($chars);
 496      }
 497    }
 498    return $tokens;
 499  }
 500  
 501  /**
 502   * Simplifies and splits a string into tokens for indexing.
 503   */
 504  function search_index_split($text) {
 505    $last = &drupal_static(__FUNCTION__);
 506    $lastsplit = &drupal_static(__FUNCTION__ . ':lastsplit');
 507  
 508    if ($last == $text) {
 509      return $lastsplit;
 510    }
 511    // Process words
 512    $text = search_simplify($text);
 513    $words = explode(' ', $text);
 514  
 515    // Save last keyword result
 516    $last = $text;
 517    $lastsplit = $words;
 518  
 519    return $words;
 520  }
 521  
 522  /**
 523   * Helper function for array_walk in search_index_split.
 524   */
 525  function _search_index_truncate(&$text) {
 526    if (is_numeric($text)) {
 527      $text = ltrim($text, '0');
 528    }
 529    $text = truncate_utf8($text, 50);
 530  }
 531  
 532  /**
 533   * Invokes hook_search_preprocess() in modules.
 534   */
 535  function search_invoke_preprocess(&$text) {
 536    foreach (module_implements('search_preprocess') as $module) {
 537      $text = module_invoke($module, 'search_preprocess', $text);
 538    }
 539  }
 540  
 541  /**
 542   * Update the full-text search index for a particular item.
 543   *
 544   * @param $sid
 545   *   An ID number identifying this particular item (e.g., node ID).
 546   * @param $module
 547   *   The machine-readable name of the module that this item comes from (a module
 548   *   that implements hook_search_info()).
 549   * @param $text
 550   *   The content of this item. Must be a piece of HTML or plain text.
 551   *
 552   * @ingroup search
 553   */
 554  function search_index($sid, $module, $text) {
 555    $minimum_word_size = variable_get('minimum_word_size', 3);
 556  
 557    // Link matching
 558    global $base_url;
 559    $node_regexp = '@href=[\'"]?(?:' . preg_quote($base_url, '@') . '/|' . preg_quote(base_path(), '@') . ')(?:\?q=)?/?((?![a-z]+:)[^\'">]+)[\'">]@i';
 560  
 561    // Multipliers for scores of words inside certain HTML tags. The weights are stored
 562    // in a variable so that modules can overwrite the default weights.
 563    // Note: 'a' must be included for link ranking to work.
 564    $tags = variable_get('search_tag_weights', array(
 565      'h1' => 25,
 566      'h2' => 18,
 567      'h3' => 15,
 568      'h4' => 12,
 569      'h5' => 9,
 570      'h6' => 6,
 571      'u' => 3,
 572      'b' => 3,
 573      'i' => 3,
 574      'strong' => 3,
 575      'em' => 3,
 576      'a' => 10));
 577  
 578    // Strip off all ignored tags to speed up processing, but insert space before/after
 579    // them to keep word boundaries.
 580    $text = str_replace(array('<', '>'), array(' <', '> '), $text);
 581    $text = strip_tags($text, '<' . implode('><', array_keys($tags)) . '>');
 582  
 583    // Split HTML tags from plain text.
 584    $split = preg_split('/\s*<([^>]+?)>\s*/', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
 585    // Note: PHP ensures the array consists of alternating delimiters and literals
 586    // and begins and ends with a literal (inserting $null as required).
 587  
 588    $tag = FALSE; // Odd/even counter. Tag or no tag.
 589    $link = FALSE; // State variable for link analyzer
 590    $score = 1; // Starting score per word
 591    $accum = ' '; // Accumulator for cleaned up data
 592    $tagstack = array(); // Stack with open tags
 593    $tagwords = 0; // Counter for consecutive words
 594    $focus = 1; // Focus state
 595  
 596    $results = array(0 => array()); // Accumulator for words for index
 597  
 598    foreach ($split as $value) {
 599      if ($tag) {
 600        // Increase or decrease score per word based on tag
 601        list($tagname) = explode(' ', $value, 2);
 602        $tagname = drupal_strtolower($tagname);
 603        // Closing or opening tag?
 604        if ($tagname[0] == '/') {
 605          $tagname = substr($tagname, 1);
 606          // If we encounter unexpected tags, reset score to avoid incorrect boosting.
 607          if (!count($tagstack) || $tagstack[0] != $tagname) {
 608            $tagstack = array();
 609            $score = 1;
 610          }
 611          else {
 612            // Remove from tag stack and decrement score
 613            $score = max(1, $score - $tags[array_shift($tagstack)]);
 614          }
 615          if ($tagname == 'a') {
 616            $link = FALSE;
 617          }
 618        }
 619        else {
 620          if (isset($tagstack[0]) && $tagstack[0] == $tagname) {
 621            // None of the tags we look for make sense when nested identically.
 622            // If they are, it's probably broken HTML.
 623            $tagstack = array();
 624            $score = 1;
 625          }
 626          else {
 627            // Add to open tag stack and increment score
 628            array_unshift($tagstack, $tagname);
 629            $score += $tags[$tagname];
 630          }
 631          if ($tagname == 'a') {
 632            // Check if link points to a node on this site
 633            if (preg_match($node_regexp, $value, $match)) {
 634              $path = drupal_get_normal_path($match[1]);
 635              if (preg_match('!(?:node|book)/(?:view/)?([0-9]+)!i', $path, $match)) {
 636                $linknid = $match[1];
 637                if ($linknid > 0) {
 638                  $node = db_query('SELECT title, nid, vid FROM {node} WHERE nid = :nid', array(':nid' => $linknid), array('target' => 'slave'))->fetchObject();
 639                  $link = TRUE;
 640                  $linktitle = $node->title;
 641                }
 642              }
 643            }
 644          }
 645        }
 646        // A tag change occurred, reset counter.
 647        $tagwords = 0;
 648      }
 649      else {
 650        // Note: use of PREG_SPLIT_DELIM_CAPTURE above will introduce empty values
 651        if ($value != '') {
 652          if ($link) {
 653            // Check to see if the node link text is its URL. If so, we use the target node title instead.
 654            if (preg_match('!^https?://!i', $value)) {
 655              $value = $linktitle;
 656            }
 657          }
 658          $words = search_index_split($value);
 659          foreach ($words as $word) {
 660            // Add word to accumulator
 661            $accum .= $word . ' ';
 662            // Check wordlength
 663            if (is_numeric($word) || drupal_strlen($word) >= $minimum_word_size) {
 664              // Links score mainly for the target.
 665              if ($link) {
 666                if (!isset($results[$linknid])) {
 667                  $results[$linknid] = array();
 668                }
 669                $results[$linknid][] = $word;
 670                // Reduce score of the link caption in the source.
 671                $focus *= 0.2;
 672              }
 673              // Fall-through
 674              if (!isset($results[0][$word])) {
 675                $results[0][$word] = 0;
 676              }
 677              $results[0][$word] += $score * $focus;
 678  
 679              // Focus is a decaying value in terms of the amount of unique words up to this point.
 680              // From 100 words and more, it decays, to e.g. 0.5 at 500 words and 0.3 at 1000 words.
 681              $focus = min(1, .01 + 3.5 / (2 + count($results[0]) * .015));
 682            }
 683            $tagwords++;
 684            // Too many words inside a single tag probably mean a tag was accidentally left open.
 685            if (count($tagstack) && $tagwords >= 15) {
 686              $tagstack = array();
 687              $score = 1;
 688            }
 689          }
 690        }
 691      }
 692      $tag = !$tag;
 693    }
 694  
 695    search_reindex($sid, $module, TRUE);
 696  
 697    // Insert cleaned up data into dataset
 698    db_insert('search_dataset')
 699      ->fields(array(
 700        'sid' => $sid,
 701        'type' => $module,
 702        'data' => $accum,
 703        'reindex' => 0,
 704      ))
 705      ->execute();
 706  
 707    // Insert results into search index
 708    foreach ($results[0] as $word => $score) {
 709      // If a word already exists in the database, its score gets increased
 710      // appropriately. If not, we create a new record with the appropriate
 711      // starting score.
 712      db_merge('search_index')
 713        ->key(array(
 714          'word' => $word,
 715          'sid' => $sid,
 716          'type' => $module,
 717        ))
 718        ->fields(array('score' => $score))
 719        ->expression('score', 'score + :score', array(':score' => $score))
 720        ->execute();
 721      search_dirty($word);
 722    }
 723    unset($results[0]);
 724  
 725    // Get all previous links from this item.
 726    $result = db_query("SELECT nid, caption FROM {search_node_links} WHERE sid = :sid AND type = :type", array(
 727      ':sid' => $sid,
 728      ':type' => $module
 729    ), array('target' => 'slave'));
 730    $links = array();
 731    foreach ($result as $link) {
 732      $links[$link->nid] = $link->caption;
 733    }
 734  
 735    // Now store links to nodes.
 736    foreach ($results as $nid => $words) {
 737      $caption = implode(' ', $words);
 738      if (isset($links[$nid])) {
 739        if ($links[$nid] != $caption) {
 740          // Update the existing link and mark the node for reindexing.
 741          db_update('search_node_links')
 742            ->fields(array('caption' => $caption))
 743            ->condition('sid', $sid)
 744            ->condition('type', $module)
 745            ->condition('nid', $nid)
 746            ->execute();
 747          search_touch_node($nid);
 748        }
 749        // Unset the link to mark it as processed.
 750        unset($links[$nid]);
 751      }
 752      elseif ($sid != $nid || $module != 'node') {
 753        // Insert the existing link and mark the node for reindexing, but don't
 754        // reindex if this is a link in a node pointing to itself.
 755        db_insert('search_node_links')
 756          ->fields(array(
 757            'caption' => $caption,
 758            'sid' => $sid,
 759            'type' => $module,
 760            'nid' => $nid,
 761          ))
 762          ->execute();
 763        search_touch_node($nid);
 764      }
 765    }
 766    // Any left-over links in $links no longer exist. Delete them and mark the nodes for reindexing.
 767    foreach ($links as $nid => $caption) {
 768      db_delete('search_node_links')
 769        ->condition('sid', $sid)
 770        ->condition('type', $module)
 771        ->condition('nid', $nid)
 772        ->execute();
 773      search_touch_node($nid);
 774    }
 775  }
 776  
 777  /**
 778   * Changes a node's changed timestamp to 'now' to force reindexing.
 779   *
 780   * @param $nid
 781   *   The node ID of the node that needs reindexing.
 782   */
 783  function search_touch_node($nid) {
 784    db_update('search_dataset')
 785      ->fields(array('reindex' => REQUEST_TIME))
 786      ->condition('type', 'node')
 787      ->condition('sid', $nid)
 788      ->execute();
 789  }
 790  
 791  /**
 792   * Implements hook_node_update_index().
 793   */
 794  function search_node_update_index($node) {
 795    // Transplant links to a node into the target node.
 796    $result = db_query("SELECT caption FROM {search_node_links} WHERE nid = :nid", array(':nid' => $node->nid), array('target' => 'slave'));
 797    $output = array();
 798    foreach ($result as $link) {
 799      $output[] = $link->caption;
 800    }
 801    if (count($output)) {
 802      return '<a>(' . implode(', ', $output) . ')</a>';
 803    }
 804  }
 805  
 806  /**
 807   * Implements hook_node_update().
 808   */
 809  function search_node_update($node) {
 810    // Reindex the node when it is updated. The node is automatically indexed
 811    // when it is added, simply by being added to the node table.
 812    search_touch_node($node->nid);
 813  }
 814  
 815  /**
 816   * Implements hook_comment_insert().
 817   */
 818  function search_comment_insert($comment) {
 819    // Reindex the node when comments are added.
 820    search_touch_node($comment->nid);
 821  }
 822  
 823  /**
 824   * Implements hook_comment_update().
 825   */
 826  function search_comment_update($comment) {
 827    // Reindex the node when comments are changed.
 828    search_touch_node($comment->nid);
 829  }
 830  
 831  /**
 832   * Implements hook_comment_delete().
 833   */
 834  function search_comment_delete($comment) {
 835    // Reindex the node when comments are deleted.
 836    search_touch_node($comment->nid);
 837  }
 838  
 839  /**
 840   * Implements hook_comment_publish().
 841   */
 842  function search_comment_publish($comment) {
 843    // Reindex the node when comments are published.
 844    search_touch_node($comment->nid);
 845  }
 846  
 847  /**
 848   * Implements hook_comment_unpublish().
 849   */
 850  function search_comment_unpublish($comment) {
 851    // Reindex the node when comments are unpublished.
 852    search_touch_node($comment->nid);
 853  }
 854  
 855  /**
 856   * Extracts a module-specific search option from a search expression.
 857   *
 858   * Search options are added using search_expression_insert(), and retrieved
 859   * using search_expression_extract(). They take the form option:value, and
 860   * are added to the ordinary keywords in the search expression.
 861   *
 862   * @param $expression
 863   *   The search expression to extract from.
 864   * @param $option
 865   *   The name of the option to retrieve from the search expression.
 866   *
 867   * @return
 868   *   The value previously stored in the search expression for option $option,
 869   *   if any. Trailing spaces in values will not be included.
 870   */
 871  function search_expression_extract($expression, $option) {
 872    if (preg_match('/(^| )' . $option . ':([^ ]*)( |$)/i', $expression, $matches)) {
 873      return $matches[2];
 874    }
 875  }
 876  
 877  /**
 878   * Adds a module-specific search option to a search expression.
 879   *
 880   * Search options are added using search_expression_insert(), and retrieved
 881   * using search_expression_extract(). They take the form option:value, and
 882   * are added to the ordinary keywords in the search expression.
 883   *
 884   * @param $expression
 885   *   The search expression to add to.
 886   * @param $option
 887   *   The name of the option to add to the search expression.
 888   * @param $value
 889   *   The value to add for the option. If present, it will replace any previous
 890   *   value added for the option. Cannot contain any spaces or | characters, as
 891   *   these are used as delimiters. If you want to add a blank value $option: to
 892   *   the search expression, pass in an empty string or a string that is composed
 893   *   of only spaces. To clear a previously-stored option without adding a
 894   *   replacement, pass in NULL for $value or omit.
 895   *
 896   * @return
 897   *   $expression, with any previous value for this option removed, and a new
 898   *   $option:$value pair added if $value was provided.
 899   */
 900  function search_expression_insert($expression, $option, $value = NULL) {
 901    // Remove any previous values stored with $option.
 902    $expression = trim(preg_replace('/(^| )' . $option . ':[^ ]*/i', '', $expression));
 903  
 904    // Set new value, if provided.
 905    if (isset($value)) {
 906      $expression .= ' ' . $option . ':' . trim($value);
 907    }
 908    return $expression;
 909  }
 910  
 911  /**
 912   * @defgroup search Search interface
 913   * @{
 914   * The Drupal search interface manages a global search mechanism.
 915   *
 916   * Modules may plug into this system to provide searches of different types of
 917   * data. Most of the system is handled by search.module, so this must be enabled
 918   * for all of the search features to work.
 919   *
 920   * There are three ways to interact with the search system:
 921   * - Specifically for searching nodes, you can implement
 922   *   hook_node_update_index() and hook_node_search_result(). However, note that
 923   *   the search system already indexes all visible output of a node; i.e.,
 924   *   everything displayed normally by hook_view() and hook_node_view(). This is
 925   *   usually sufficient. You should only use this mechanism if you want
 926   *   additional, non-visible data to be indexed.
 927   * - Implement hook_search_info(). This will create a search tab for your module
 928   *   on the /search page with a simple keyword search form. You will also need
 929   *   to implement hook_search_execute() to perform the search.
 930   * - Implement hook_update_index(). This allows your module to use Drupal's
 931   *   HTML indexing mechanism for searching full text efficiently.
 932   *
 933   * If your module needs to provide a more complicated search form, then you need
 934   * to implement it yourself without hook_search_info(). In that case, you should
 935   * define it as a local task (tab) under the /search page (e.g. /search/mymodule)
 936   * so that users can easily find it.
 937   */
 938  
 939  /**
 940   * Builds a search form.
 941   *
 942   * @param $action
 943   *   Form action. Defaults to "search/$path", where $path is the search path
 944   *   associated with the module in its hook_search_info(). This will be
 945   *   run through url().
 946   * @param $keys
 947   *   The search string entered by the user, containing keywords for the search.
 948   * @param $module
 949   *   The search module to render the form for: a module that implements
 950   *   hook_search_info(). If not supplied, the default search module is used.
 951   * @param $prompt
 952   *   Label for the keywords field. Defaults to t('Enter your keywords') if NULL.
 953   *   Supply '' to omit.
 954   *
 955   * @return
 956   *   A Form API array for the search form.
 957   */
 958  function search_form($form, &$form_state, $action = '', $keys = '', $module = NULL, $prompt = NULL) {
 959    $module_info = FALSE;
 960    if (!$module) {
 961      $module_info = search_get_default_module_info();
 962    }
 963    else {
 964      $info = search_get_info();
 965      $module_info = isset($info[$module]) ? $info[$module] : FALSE;
 966    }
 967  
 968    // Sanity check.
 969    if (!$module_info) {
 970      form_set_error(NULL, t('Search is currently disabled.'), 'error');
 971      return $form;
 972    }
 973  
 974    if (!$action) {
 975      $action = 'search/' . $module_info['path'];
 976    }
 977    if (!isset($prompt)) {
 978      $prompt = t('Enter your keywords');
 979    }
 980  
 981    $form['#action'] = url($action);
 982    // Record the $action for later use in redirecting.
 983    $form_state['action'] = $action;
 984    $form['#attributes']['class'][] = 'search-form';
 985    $form['module'] = array('#type' => 'value', '#value' => $module);
 986    $form['basic'] = array('#type' => 'container', '#attributes' => array('class' => array('container-inline')));
 987    $form['basic']['keys'] = array(
 988      '#type' => 'textfield',
 989      '#title' => $prompt,
 990      '#default_value' => $keys,
 991      '#size' => $prompt ? 40 : 20,
 992      '#maxlength' => 255,
 993    );
 994    // processed_keys is used to coordinate keyword passing between other forms
 995    // that hook into the basic search form.
 996    $form['basic']['processed_keys'] = array('#type' => 'value', '#value' => '');
 997    $form['basic']['submit'] = array('#type' => 'submit', '#value' => t('Search'));
 998  
 999    return $form;
1000  }
1001  
1002  /**
1003   * Form builder; Output a search form for the search block's search box.
1004   *
1005   * @ingroup forms
1006   * @see search_box_form_submit()
1007   * @see search-block-form.tpl.php
1008   */
1009  function search_box($form, &$form_state, $form_id) {
1010    $form[$form_id] = array(
1011      '#type' => 'textfield',
1012      '#title' => t('Search'),
1013      '#title_display' => 'invisible',
1014      '#size' => 15,
1015      '#default_value' => '',
1016      '#attributes' => array('title' => t('Enter the terms you wish to search for.')),
1017    );
1018    $form['actions'] = array('#type' => 'actions');
1019    $form['actions']['submit'] = array('#type' => 'submit', '#value' => t('Search'));
1020    $form['#submit'][] = 'search_box_form_submit';
1021  
1022    return $form;
1023  }
1024  
1025  /**
1026   * Process a block search form submission.
1027   */
1028  function search_box_form_submit($form, &$form_state) {
1029    // The search form relies on control of the redirect destination for its
1030    // functionality, so we override any static destination set in the request,
1031    // for example by drupal_access_denied() or drupal_not_found()
1032    // (see http://drupal.org/node/292565).
1033    if (isset($_GET['destination'])) {
1034      unset($_GET['destination']);
1035    }
1036  
1037    // Check to see if the form was submitted empty.
1038    // If it is empty, display an error message.
1039    // (This method is used instead of setting #required to TRUE for this field
1040    // because that results in a confusing error message.  It would say a plain
1041    // "field is required" because the search keywords field has no title.
1042    // The error message would also complain about a missing #title field.)
1043    if ($form_state['values']['search_block_form'] == '') {
1044      form_set_error('keys', t('Please enter some keywords.'));
1045    }
1046  
1047    $form_id = $form['form_id']['#value'];
1048    $info = search_get_default_module_info();
1049    if ($info) {
1050      $form_state['redirect'] = 'search/' . $info['path'] . '/' . trim($form_state['values'][$form_id]);
1051    }
1052    else {
1053      form_set_error(NULL, t('Search is currently disabled.'), 'error');
1054    }
1055  }
1056  
1057  /**
1058   * Process variables for search-block-form.tpl.php.
1059   *
1060   * The $variables array contains the following arguments:
1061   * - $form
1062   *
1063   * @see search-block-form.tpl.php
1064   */
1065  function template_preprocess_search_block_form(&$variables) {
1066    $variables['search'] = array();
1067    $hidden = array();
1068    // Provide variables named after form keys so themers can print each element independently.
1069    foreach (element_children($variables['form']) as $key) {
1070      $type = $variables['form'][$key]['#type'];
1071      if ($type == 'hidden' || $type == 'token') {
1072        $hidden[] = drupal_render($variables['form'][$key]);
1073      }
1074      else {
1075        $variables['search'][$key] = drupal_render($variables['form'][$key]);
1076      }
1077    }
1078    // Hidden form elements have no value to themers. No need for separation.
1079    $variables['search']['hidden'] = implode($hidden);
1080    // Collect all form elements to make it easier to print the whole form.
1081    $variables['search_form'] = implode($variables['search']);
1082  }
1083  
1084  /**
1085   * Performs a search by calling hook_search_execute().
1086   *
1087   * @param $keys
1088   *   Keyword query to search on.
1089   * @param $module
1090   *   Search module to search.
1091   * @param $conditions
1092   *   Optional array of additional search conditions.
1093   *
1094   * @return
1095   *   Renderable array of search results. No return value if $keys are not
1096   *   supplied or if the given search module is not active.
1097   */
1098  function search_data($keys, $module, $conditions = NULL) {
1099    if (module_hook($module, 'search_execute')) {
1100      $results = module_invoke($module, 'search_execute', $keys, $conditions);
1101      if (module_hook($module, 'search_page')) {
1102        return module_invoke($module, 'search_page', $results);
1103      }
1104      else {
1105        return array(
1106          '#theme' => 'search_results',
1107          '#results' => $results,
1108          '#module' => $module,
1109        );
1110      }
1111    }
1112  }
1113  
1114  /**
1115   * Returns snippets from a piece of text, with certain keywords highlighted.
1116   * Used for formatting search results.
1117   *
1118   * @param $keys
1119   *   A string containing a search query.
1120   *
1121   * @param $text
1122   *   The text to extract fragments from.
1123   *
1124   * @return
1125   *   A string containing HTML for the excerpt.
1126   */
1127  function search_excerpt($keys, $text) {
1128    // We highlight around non-indexable or CJK characters.
1129    $boundary = '(?:(?<=[' . PREG_CLASS_UNICODE_WORD_BOUNDARY . PREG_CLASS_CJK . '])|(?=[' . PREG_CLASS_UNICODE_WORD_BOUNDARY . PREG_CLASS_CJK . ']))';
1130  
1131    // Extract positive keywords and phrases
1132    preg_match_all('/ ("([^"]+)"|(?!OR)([^" ]+))/', ' ' . $keys, $matches);
1133    $keys = array_merge($matches[2], $matches[3]);
1134  
1135    // Prepare text by stripping HTML tags and decoding HTML entities.
1136    $text = strip_tags(str_replace(array('<', '>'), array(' <', '> '), $text));
1137    $text = decode_entities($text);
1138  
1139    // Slash-escape quotes in the search keyword string.
1140    array_walk($keys, '_search_excerpt_replace');
1141    $workkeys = $keys;
1142  
1143    // Extract fragments around keywords.
1144    // First we collect ranges of text around each keyword, starting/ending
1145    // at spaces, trying to get to 256 characters.
1146    // If the sum of all fragments is too short, we look for second occurrences.
1147    $ranges = array();
1148    $included = array();
1149    $foundkeys = array();
1150    $length = 0;
1151    while ($length < 256 && count($workkeys)) {
1152      foreach ($workkeys as $k => $key) {
1153        if (strlen($key) == 0) {
1154          unset($workkeys[$k]);
1155          unset($keys[$k]);
1156          continue;
1157        }
1158        if ($length >= 256) {
1159          break;
1160        }
1161        // Remember occurrence of key so we can skip over it if more occurrences
1162        // are desired.
1163        if (!isset($included[$key])) {
1164          $included[$key] = 0;
1165        }
1166        // Locate a keyword (position $p, always >0 because $text starts with a
1167        // space). First try bare keyword, but if that doesn't work, try to find a
1168        // derived form from search_simplify().
1169        $p = 0;
1170        if (preg_match('/' . $boundary . $key . $boundary . '/iu', $text, $match, PREG_OFFSET_CAPTURE, $included[$key])) {
1171          $p = $match[0][1];
1172        }
1173        else {
1174          $info = search_simplify_excerpt_match($key, $text, $included[$key], $boundary);
1175          if ($info['where']) {
1176            $p = $info['where'];
1177            if ($info['keyword']) {
1178              $foundkeys[] = $info['keyword'];
1179            }
1180          }
1181        }
1182        // Now locate a space in front (position $q) and behind it (position $s),
1183        // leaving about 60 characters extra before and after for context.
1184        // Note that a space was added to the front and end of $text above.
1185        if ($p) {
1186          if (($q = strpos(' ' . $text, ' ', max(0, $p - 61))) !== FALSE) {
1187            $end = substr($text . ' ', $p, 80);
1188            if (($s = strrpos($end, ' ')) !== FALSE) {
1189              // Account for the added spaces.
1190              $q = max($q - 1, 0);
1191              $s = min($s, strlen($end) - 1);
1192              $ranges[$q] = $p + $s;
1193              $length += $p + $s - $q;
1194              $included[$key] = $p + 1;
1195            }
1196            else {
1197              unset($workkeys[$k]);
1198            }
1199          }
1200          else {
1201            unset($workkeys[$k]);
1202          }
1203        }
1204        else {
1205          unset($workkeys[$k]);
1206        }
1207      }
1208    }
1209  
1210    if (count($ranges) == 0) {
1211      // We didn't find any keyword matches, so just return the first part of the
1212      // text. We also need to re-encode any HTML special characters that we
1213      // entity-decoded above.
1214      return check_plain(truncate_utf8($text, 256, TRUE, TRUE));
1215    }
1216  
1217    // Sort the text ranges by starting position.
1218    ksort($ranges);
1219  
1220    // Now we collapse overlapping text ranges into one. The sorting makes it O(n).
1221    $newranges = array();
1222    foreach ($ranges as $from2 => $to2) {
1223      if (!isset($from1)) {
1224        $from1 = $from2;
1225        $to1 = $to2;
1226        continue;
1227      }
1228      if ($from2 <= $to1) {
1229        $to1 = max($to1, $to2);
1230      }
1231      else {
1232        $newranges[$from1] = $to1;
1233        $from1 = $from2;
1234        $to1 = $to2;
1235      }
1236    }
1237    $newranges[$from1] = $to1;
1238  
1239    // Fetch text
1240    $out = array();
1241    foreach ($newranges as $from => $to) {
1242      $out[] = substr($text, $from, $to - $from);
1243    }
1244  
1245    // Let translators have the ... separator text as one chunk.
1246    $dots = explode('!excerpt', t('... !excerpt ... !excerpt ...'));
1247  
1248    $text = (isset($newranges[0]) ? '' : $dots[0]) . implode($dots[1], $out) . $dots[2];
1249    $text = check_plain($text);
1250  
1251    // Slash-escape quotes in keys found in a derived form and merge with original keys.
1252    array_walk($foundkeys, '_search_excerpt_replace');
1253    $keys = array_merge($keys, $foundkeys);
1254  
1255    // Highlight keywords. Must be done at once to prevent conflicts ('strong' and '<strong>').
1256    $text = preg_replace('/' . $boundary . '(' . implode('|', $keys) . ')' . $boundary . '/iu', '<strong>\0</strong>', $text);
1257    return $text;
1258  }
1259  
1260  /**
1261   * @} End of "defgroup search".
1262   */
1263  
1264  /**
1265   * Helper function for array_walk() in search_excerpt().
1266   */
1267  function _search_excerpt_replace(&$text) {
1268    $text = preg_quote($text, '/');
1269  }
1270  
1271  /**
1272   * Find words in the original text that matched via search_simplify().
1273   *
1274   * This is called in search_excerpt() if an exact match is not found in the
1275   * text, so that we can find the derived form that matches.
1276   *
1277   * @param $key
1278   *   The keyword to find.
1279   * @param $text
1280   *   The text to search for the keyword.
1281   * @param $offset
1282   *   Offset position in $text to start searching at.
1283   * @param $boundary
1284   *   Text to include in a regular expression that will match a word boundary.
1285   *
1286   * @return
1287   *   FALSE if no match is found. If a match is found, return an associative
1288   *   array with element 'where' giving the position of the match, and element
1289   *   'keyword' giving the actual word found in the text at that position.
1290   */
1291  function search_simplify_excerpt_match($key, $text, $offset, $boundary) {
1292    $pos = NULL;
1293    $simplified_key = search_simplify($key);
1294    $simplified_text = search_simplify($text);
1295  
1296    // Return immediately if simplified key or text are empty.
1297    if (!$simplified_key || !$simplified_text) {
1298      return FALSE;
1299    }
1300  
1301    // Check if we have a match after simplification in the text.
1302    if (!preg_match('/' . $boundary . $simplified_key . $boundary . '/iu', $simplified_text, $match, PREG_OFFSET_CAPTURE, $offset)) {
1303      return FALSE;
1304    }
1305  
1306    // If we get here, we have a match. Now find the exact location of the match
1307    // and the original text that matched. Start by splitting up the text by all
1308    // potential starting points of the matching text and iterating through them.
1309    $split = array_filter(preg_split('/' . $boundary . '/iu', $text, -1, PREG_SPLIT_OFFSET_CAPTURE), '_search_excerpt_match_filter');
1310    foreach ($split as $value) {
1311      // Skip starting points before the offset.
1312      if ($value[1] < $offset) {
1313        continue;
1314      }
1315  
1316      // Check a window of 80 characters after the starting point for a match,
1317      // based on the size of the excerpt window.
1318      $window = substr($text, $value[1], 80);
1319      $simplified_window = search_simplify($window);
1320      if (strpos($simplified_window, $simplified_key) === 0) {
1321        // We have a match in this window. Store the position of the match.
1322        $pos = $value[1];
1323        // Iterate through the text in the window until we find the full original
1324        // matching text.
1325        $length = strlen($window);
1326        for ($i = 1; $i <= $length; $i++) {
1327          $keyfound = substr($text, $value[1], $i);
1328          if ($simplified_key == search_simplify($keyfound)) {
1329            break;
1330          }
1331        }
1332        break;
1333      }
1334    }
1335  
1336    return $pos ? array('where' => $pos, 'keyword' => $keyfound) : FALSE;
1337  }
1338  
1339  /**
1340   * Helper function for array_filter() in search_search_excerpt_match().
1341   */
1342  function _search_excerpt_match_filter($var) {
1343    return strlen(trim($var[0]));
1344  }
1345  
1346  /**
1347   * Implements hook_forms().
1348   */
1349  function search_forms() {
1350    $forms['search_block_form']= array(
1351      'callback' => 'search_box',
1352      'callback arguments' => array('search_block_form'),
1353    );
1354    return $forms;
1355  }
1356  

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