public function test_is_valid_plugin_name()
 {
     $this->assertTrue(is_valid_plugin_name('forum'));
     $this->assertTrue(is_valid_plugin_name('forum2'));
     $this->assertTrue(is_valid_plugin_name('feedback360'));
     $this->assertTrue(is_valid_plugin_name('online_users'));
     $this->assertTrue(is_valid_plugin_name('blond_online_users'));
     $this->assertFalse(is_valid_plugin_name('online__users'));
     $this->assertFalse(is_valid_plugin_name('forum '));
     $this->assertFalse(is_valid_plugin_name('forum.old'));
     $this->assertFalse(is_valid_plugin_name('xx-yy'));
     $this->assertFalse(is_valid_plugin_name('2xx'));
     $this->assertFalse(is_valid_plugin_name('Xx'));
     $this->assertFalse(is_valid_plugin_name('_xx'));
     $this->assertFalse(is_valid_plugin_name('xx_'));
 }

 /**
  * Returns an array of plugins without using core methods.
  *
  * This function explicitly does NOT use core functions as it will in some circumstances be called before Moodle has
  * finished initialising. This happens when loading configuration for instance.
  *
  * @return string
  */
 public static function early_get_cache_plugins()
 {
     global $CFG;
     $result = array();
     $ignored = array('CVS', '_vti_cnf', 'simpletest', 'db', 'yui', 'tests');
     $fulldir = $CFG->dirroot . '/cache/stores';
     $items = new DirectoryIterator($fulldir);
     foreach ($items as $item) {
         if ($item->isDot() or !$item->isDir()) {
             continue;
         }
         $pluginname = $item->getFilename();
         if (in_array($pluginname, $ignored)) {
             continue;
         }
         if (!is_valid_plugin_name($pluginname)) {
             // Better ignore plugins with problematic names here.
             continue;
         }
         $result[$pluginname] = $fulldir . '/' . $pluginname;
         unset($item);
     }
     unset($items);
     return $result;
 }

//.........这里部分代码省略.........
                                break 2;
                            } else {
                                $open = true;
                            }
                        }
                        if ($open) {
                            break;
                        }
                        return $param;
                    }
                }
            } while (false);
            // Easy, just strip all tags, if we ever want to fix orphaned '&' we have to do that in format_string().
            return strip_tags($param);
        case PARAM_COMPONENT:
            // We do not want any guessing here, either the name is correct or not
            // please note only normalised component names are accepted.
            if (!preg_match('/^[a-z]+(_[a-z][a-z0-9_]*)?[a-z0-9]+$/', $param)) {
                return '';
            }
            if (strpos($param, '__') !== false) {
                return '';
            }
            if (strpos($param, 'mod_') === 0) {
                // Module names must not contain underscores because we need to differentiate them from invalid plugin types.
                if (substr_count($param, '_') != 1) {
                    return '';
                }
            }
            return $param;
        case PARAM_PLUGIN:
        case PARAM_AREA:
            // We do not want any guessing here, either the name is correct or not.
            if (!is_valid_plugin_name($param)) {
                return '';
            }
            return $param;
        case PARAM_SAFEDIR:
            // Remove everything not a-zA-Z0-9_- .
            return preg_replace('/[^a-zA-Z0-9_-]/i', '', $param);
        case PARAM_SAFEPATH:
            // Remove everything not a-zA-Z0-9/_- .
            return preg_replace('/[^a-zA-Z0-9\\/_-]/i', '', $param);
        case PARAM_FILE:
            // Strip all suspicious characters from filename.
            $param = fix_utf8($param);
            $param = preg_replace('~[[:cntrl:]]|[&<>"`\\|\':\\\\/]~u', '', $param);
            if ($param === '.' || $param === '..') {
                $param = '';
            }
            return $param;
        case PARAM_PATH:
            // Strip all suspicious characters from file path.
            $param = fix_utf8($param);
            $param = str_replace('\\', '/', $param);
            // Explode the path and clean each element using the PARAM_FILE rules.
            $breadcrumb = explode('/', $param);
            foreach ($breadcrumb as $key => $crumb) {
                if ($crumb === '.' && $key === 0) {
                    // Special condition to allow for relative current path such as ./currentdirfile.txt.
                } else {
                    $crumb = clean_param($crumb, PARAM_FILE);
                }
                $breadcrumb[$key] = $crumb;
            }
            $param = implode('/', $breadcrumb);

/**
 * Simplified version of get_list_of_plugins()
 * @param string $plugintype type of plugin
 * @return array name=>fulllocation pairs of plugins of given type
 */
function get_plugin_list($plugintype)
{
    global $CFG;
    // We use the dirroot as an identifier here because if it has changed the whole cache
    // can be considered invalid.
    $cache = cache::make('core', 'pluginlist', array('dirroot' => $CFG->dirroot));
    $cached = $cache->get($plugintype);
    if ($cached !== false) {
        return $cached;
    }
    $ignored = array('CVS', '_vti_cnf', 'simpletest', 'db', 'yui', 'tests');
    if ($plugintype == 'auth') {
        // Historically we have had an auth plugin called 'db', so allow a special case.
        $key = array_search('db', $ignored);
        if ($key !== false) {
            unset($ignored[$key]);
        }
    }
    if ($plugintype === '') {
        $plugintype = 'mod';
    }
    $fulldirs = array();
    if ($plugintype === 'mod') {
        // mod is an exception because we have to call this function from get_plugin_types()
        $fulldirs[] = $CFG->dirroot . '/mod';
    } else {
        if ($plugintype === 'editor') {
            // Exception also needed for editor for same reason.
            $fulldirs[] = $CFG->dirroot . '/lib/editor';
        } else {
            if ($plugintype === 'theme') {
                $fulldirs[] = $CFG->dirroot . '/theme';
                // themes are special because they may be stored also in separate directory
                if (!empty($CFG->themedir) and file_exists($CFG->themedir) and is_dir($CFG->themedir)) {
                    $fulldirs[] = $CFG->themedir;
                }
            } else {
                $types = get_plugin_types(true);
                if (!array_key_exists($plugintype, $types)) {
                    $cache->set($plugintype, array());
                    return array();
                }
                $fulldir = $types[$plugintype];
                if (!file_exists($fulldir)) {
                    $cache->set($plugintype, array());
                    return array();
                }
                $fulldirs[] = $fulldir;
            }
        }
    }
    $result = array();
    foreach ($fulldirs as $fulldir) {
        if (!is_dir($fulldir)) {
            continue;
        }
        $items = new DirectoryIterator($fulldir);
        foreach ($items as $item) {
            if ($item->isDot() or !$item->isDir()) {
                continue;
            }
            $pluginname = $item->getFilename();
            if (in_array($pluginname, $ignored)) {
                continue;
            }
            if (!is_valid_plugin_name($pluginname)) {
                // Better ignore plugins with problematic names here.
                continue;
            }
            $result[$pluginname] = $fulldir . '/' . $pluginname;
            unset($item);
        }
        unset($items);
    }
    //TODO: implement better sorting once we migrated all plugin names to 'pluginname', ksort does not work for unicode, that is why we have to sort by the dir name, not the strings!
    ksort($result);
    $cache->set($plugintype, $result);
    return $result;
}