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   1  <?php
   2  
   3  /**
   4   * @file
   5   * Functions to handle paths in Drupal, including path aliasing.
   6   *
   7   * These functions are not loaded for cached pages, but modules that need
   8   * to use them in hook_init() or hook exit() can make them available, by
   9   * executing "drupal_bootstrap(DRUPAL_BOOTSTRAP_PATH);".
  10   */
  11  
  12  /**
  13   * Initialize the $_GET['q'] variable to the proper normal path.
  14   */
  15  function drupal_init_path() {
  16    if (!empty($_GET['q'])) {
  17      $_GET['q'] = drupal_get_normal_path(trim($_GET['q'], '/'));
  18    }
  19    else {
  20      $_GET['q'] = drupal_get_normal_path(variable_get('site_frontpage', 'node'));
  21    }
  22  }
  23  
  24  /**
  25   * Given an alias, return its Drupal system URL if one exists. Given a Drupal
  26   * system URL return one of its aliases if such a one exists. Otherwise,
  27   * return FALSE.
  28   *
  29   * @param $action
  30   *   One of the following values:
  31   *   - wipe: delete the alias cache.
  32   *   - alias: return an alias for a given Drupal system path (if one exists).
  33   *   - source: return the Drupal system URL for a path alias (if one exists).
  34   * @param $path
  35   *   The path to investigate for corresponding aliases or system URLs.
  36   * @param $path_language
  37   *   Optional language code to search the path with. Defaults to the page language.
  38   *   If there's no path defined for that language it will search paths without
  39   *   language.
  40   *
  41   * @return
  42   *   Either a Drupal system path, an aliased path, or FALSE if no path was
  43   *   found.
  44   */
  45  function drupal_lookup_path($action, $path = '', $path_language = '') {
  46    global $language;
  47    // $map is an array with language keys, holding arrays of Drupal paths to alias relations
  48    static $map = array(), $no_src = array(), $count;
  49  
  50    $path_language = $path_language ? $path_language : $language->language;
  51  
  52    // Use $count to avoid looking up paths in subsequent calls if there simply are no aliases
  53    if (!isset($count)) {
  54      $count = db_result(db_query('SELECT COUNT(pid) FROM {url_alias}'));
  55    }
  56  
  57    if ($action == 'wipe') {
  58      $map = array();
  59      $no_src = array();
  60      $count = NULL;
  61    }
  62    elseif ($count > 0 && $path != '') {
  63      if ($action == 'alias') {
  64        if (isset($map[$path_language][$path])) {
  65          return $map[$path_language][$path];
  66        }
  67        // Get the most fitting result falling back with alias without language
  68        $alias = db_result(db_query("SELECT dst FROM {url_alias} WHERE src = '%s' AND language IN('%s', '') ORDER BY language DESC, pid DESC", $path, $path_language));
  69        $map[$path_language][$path] = $alias;
  70        return $alias;
  71      }
  72      // Check $no_src for this $path in case we've already determined that there
  73      // isn't a path that has this alias
  74      elseif ($action == 'source' && !isset($no_src[$path_language][$path])) {
  75        // Look for the value $path within the cached $map
  76        $src = FALSE;
  77        if (!isset($map[$path_language]) || !($src = array_search($path, $map[$path_language]))) {
  78          // Get the most fitting result falling back with alias without language
  79          if ($src = db_result(db_query("SELECT src FROM {url_alias} WHERE dst = '%s' AND language IN('%s', '') ORDER BY language DESC, pid DESC", $path, $path_language))) {
  80            $map[$path_language][$src] = $path;
  81          }
  82          else {
  83            // We can't record anything into $map because we do not have a valid
  84            // index and there is no need because we have not learned anything
  85            // about any Drupal path. Thus cache to $no_src.
  86            $no_src[$path_language][$path] = TRUE;
  87          }
  88        }
  89        return $src;
  90      }
  91    }
  92  
  93    return FALSE;
  94  }
  95  
  96  /**
  97   * Given an internal Drupal path, return the alias set by the administrator.
  98   *
  99   * @param $path
 100   *   An internal Drupal path.
 101   * @param $path_language
 102   *   An optional language code to look up the path in.
 103   *
 104   * @return
 105   *   An aliased path if one was found, or the original path if no alias was
 106   *   found.
 107   */
 108  function drupal_get_path_alias($path, $path_language = '') {
 109    $result = $path;
 110    if ($alias = drupal_lookup_path('alias', $path, $path_language)) {
 111      $result = $alias;
 112    }
 113    return $result;
 114  }
 115  
 116  /**
 117   * Given a path alias, return the internal path it represents.
 118   *
 119   * @param $path
 120   *   A Drupal path alias.
 121   * @param $path_language
 122   *   An optional language code to look up the path in.
 123   *
 124   * @return
 125   *   The internal path represented by the alias, or the original alias if no
 126   *   internal path was found.
 127   */
 128  function drupal_get_normal_path($path, $path_language = '') {
 129    $result = $path;
 130    if ($src = drupal_lookup_path('source', $path, $path_language)) {
 131      $result = $src;
 132    }
 133    if (function_exists('custom_url_rewrite_inbound')) {
 134      // Modules may alter the inbound request path by reference.
 135      custom_url_rewrite_inbound($result, $path, $path_language);
 136    }
 137    return $result;
 138  }
 139  
 140  /**
 141   * Return a component of the current Drupal path.
 142   *
 143   * When viewing a page at the path "admin/content/types", for example, arg(0)
 144   * would return "admin", arg(1) would return "content", and arg(2) would return
 145   * "types".
 146   *
 147   * Avoid use of this function where possible, as resulting code is hard to read.
 148   * Instead, attempt to use named arguments in menu callback functions. See the
 149   * explanation in menu.inc for how to construct callbacks that take arguments.
 150   *
 151   * @param $index
 152   *   The index of the component, where each component is separated by a '/'
 153   *   (forward-slash), and where the first component has an index of 0 (zero).
 154   * @param $path
 155   *   A path to break into components. Defaults to the path of the current page.
 156   *
 157   * @return
 158   *   The component specified by $index, or NULL if the specified component was
 159   *   not found. If called without arguments, it returns an array containing all
 160   *   the components of the current path.
 161   */
 162  function arg($index = NULL, $path = NULL) {
 163    static $arguments;
 164  
 165    if (!isset($path)) {
 166      $path = $_GET['q'];
 167    }
 168    if (!isset($arguments[$path])) {
 169      $arguments[$path] = explode('/', $path);
 170    }
 171    if (!isset($index)) {
 172      return $arguments[$path];
 173    }
 174    if (isset($arguments[$path][$index])) {
 175      return $arguments[$path][$index];
 176    }
 177  }
 178  
 179  /**
 180   * Get the title of the current page, for display on the page and in the title bar.
 181   *
 182   * @return
 183   *   The current page's title.
 184   */
 185  function drupal_get_title() {
 186    $title = drupal_set_title();
 187  
 188    // during a bootstrap, menu.inc is not included and thus we cannot provide a title
 189    if (!isset($title) && function_exists('menu_get_active_title')) {
 190      $title = check_plain(menu_get_active_title());
 191    }
 192  
 193    return $title;
 194  }
 195  
 196  /**
 197   * Set the title of the current page, for display on the page and in the title bar.
 198   *
 199   * @param $title
 200   *   Optional string value to assign to the page title; or if set to NULL
 201   *   (default), leaves the current title unchanged.
 202   *
 203   * @return
 204   *   The updated title of the current page.
 205   */
 206  function drupal_set_title($title = NULL) {
 207    static $stored_title;
 208  
 209    if (isset($title)) {
 210      $stored_title = $title;
 211    }
 212    return $stored_title;
 213  }
 214  
 215  /**
 216   * Check if the current page is the front page.
 217   *
 218   * @return
 219   *   Boolean value: TRUE if the current page is the front page; FALSE if otherwise.
 220   */
 221  function drupal_is_front_page() {
 222    static $is_front_page;
 223  
 224    if (!isset($is_front_page)) {
 225      // As drupal_init_path updates $_GET['q'] with the 'site_frontpage' path,
 226      // we can check it against the 'site_frontpage' variable.
 227      $is_front_page = ($_GET['q'] == drupal_get_normal_path(variable_get('site_frontpage', 'node')));
 228    }
 229  
 230    return $is_front_page;
 231  }
 232  
 233  /**
 234   * Check if a path matches any pattern in a set of patterns.
 235   *
 236   * @param $path
 237   *   The path to match.
 238   * @param $patterns
 239   *   String containing a set of patterns separated by \n, \r or \r\n.
 240   *
 241   * @return
 242   *   1 if there is a match, 0 if there is not a match.
 243   */
 244  function drupal_match_path($path, $patterns) {
 245    static $regexps;
 246  
 247    if (!isset($regexps[$patterns])) {
 248      $regexps[$patterns] = '/^('. preg_replace(array('/(\r\n?|\n)/', '/\\\\\*/', '/(^|\|)\\\\<front\\\\>($|\|)/'), array('|', '.*', '\1'. preg_quote(variable_get('site_frontpage', 'node'), '/') .'\2'), preg_quote($patterns, '/')) .')$/';
 249    }
 250    return preg_match($regexps[$patterns], $path);
 251  }