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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  
  18  /**
  19   * Utility class for browsing of system files.
  20   *
  21   * @package    core_files
  22   * @copyright  2008 Petr Skoda (http://skodak.org)
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  defined('MOODLE_INTERNAL') || die();
  27  
  28  /**
  29   * Represents the system context in the tree navigated by {@link file_browser}.
  30   *
  31   * @package    core_files
  32   * @copyright  2008 Petr Skoda (http://skodak.org)
  33   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  34   */
  35  class file_info_context_system extends file_info {
  36  
  37      /**
  38       * Constructor
  39       *
  40       * @param file_browser $browser file_browser instance
  41       * @param stdClass $context context object
  42       */
  43      public function __construct($browser, $context) {
  44          parent::__construct($browser, $context);
  45      }
  46  
  47      /**
  48       * Return information about this specific part of context level
  49       *
  50       * @param string $component component
  51       * @param string $filearea file area
  52       * @param int $itemid item ID
  53       * @param string $filepath file path
  54       * @param string $filename file name
  55       * @return file_info|null file_info instance or null if not found or access not allowed
  56       */
  57      public function get_file_info($component, $filearea, $itemid, $filepath, $filename) {
  58          if (empty($component)) {
  59              return $this;
  60          }
  61  
  62          $methodname = "get_area_{$component}_{$filearea}";
  63  
  64          if (method_exists($this, $methodname)) {
  65              return $this->$methodname($itemid, $filepath, $filename);
  66          }
  67  
  68          return null;
  69      }
  70  
  71      /**
  72       * Gets a stored file for the backup course filearea directory.
  73       *
  74       * @param int $itemid item ID
  75       * @param string $filepath file path
  76       * @param string $filename file name
  77       * @return file_info|null file_info instance or null if not found or access not allowed
  78       */
  79      protected function get_area_backup_course($itemid, $filepath, $filename) {
  80          global $CFG;
  81  
  82          if (!isloggedin()) {
  83              return null;
  84          }
  85  
  86          if (!has_any_capability(array('moodle/backup:backupcourse', 'moodle/restore:restorecourse'), $this->context)) {
  87              return null;
  88          }
  89  
  90          if (is_null($itemid)) {
  91              return $this;
  92          }
  93  
  94          $fs = get_file_storage();
  95  
  96          $filepath = is_null($filepath) ? '/' : $filepath;
  97          $filename = is_null($filename) ? '.' : $filename;
  98          if (!$storedfile = $fs->get_file($this->context->id, 'backup', 'course', 0, $filepath, $filename)) {
  99              if ($filepath === '/' && $filename === '.') {
 100                  $storedfile = new virtual_root_file($this->context->id, 'backup', 'course', 0);
 101              } else {
 102                  // Not found.
 103                  return null;
 104              }
 105          }
 106  
 107          $downloadable = has_capability('moodle/backup:downloadfile', $this->context);
 108          $uploadable = has_capability('moodle/restore:uploadfile', $this->context);
 109  
 110          $urlbase = $CFG->wwwroot . '/pluginfile.php';
 111          return new file_info_stored($this->browser, $this->context, $storedfile, $urlbase,
 112              get_string('coursebackup', 'repository'), false, $downloadable, $uploadable, false);
 113      }
 114  
 115      /**
 116       * Returns localised visible name.
 117       *
 118       * @return string
 119       */
 120      public function get_visible_name() {
 121          return get_string('arearoot', 'repository');
 122      }
 123  
 124      /**
 125       * Whether or not new files or directories can be added
 126       *
 127       * @return bool
 128       */
 129      public function is_writable() {
 130          return false;
 131      }
 132  
 133      /**
 134       * Whether or not this is a directory
 135       *
 136       * @return bool
 137       */
 138      public function is_directory() {
 139          return true;
 140      }
 141  
 142      /**
 143       * Returns list of children.
 144       *
 145       * @return array of file_info instances
 146       */
 147      public function get_children() {
 148          global $DB;
 149  
 150          $children = array();
 151  
 152          // Add course categories on the top level that are either visible or user is able to view hidden categories.
 153          $course_cats = $DB->get_records('course_categories', array('parent'=>0), 'sortorder', 'id,visible');
 154          foreach ($course_cats as $category) {
 155              $context = context_coursecat::instance($category->id);
 156              if (!$category->visible and !has_capability('moodle/category:viewhiddencategories', $context)) {
 157                  continue;
 158              }
 159              if ($child = $this->browser->get_file_info($context)) {
 160                  $children[] = $child;
 161              }
 162          }
 163  
 164          // Add courses where user is enrolled that are located in hidden course categories because they would not
 165          // be present in the above tree but user may still be able to access files in them.
 166          if ($hiddencontexts = $this->get_inaccessible_coursecat_contexts()) {
 167              $courses = enrol_get_my_courses();
 168              foreach ($courses as $course) {
 169                  $context = context_course::instance($course->id);
 170                  $parents = $context->get_parent_context_ids();
 171                  if (array_intersect($hiddencontexts, $parents)) {
 172                      // This course has hidden parent category.
 173                      if ($child = $this->browser->get_file_info($context)) {
 174                          $children[] = $child;
 175                      }
 176                  }
 177              }
 178          }
 179  
 180          return $children;
 181      }
 182  
 183      /**
 184       * Returns list of course categories contexts that current user can not see
 185       *
 186       * @return array array of course categories contexts ids
 187       */
 188      protected function get_inaccessible_coursecat_contexts() {
 189          global $DB;
 190  
 191          $sql = context_helper::get_preload_record_columns_sql('ctx');
 192          $records = $DB->get_records_sql("SELECT ctx.id, $sql
 193              FROM {course_categories} c
 194              JOIN {context} ctx ON c.id = ctx.instanceid AND ctx.contextlevel = ?
 195              WHERE c.visible = ?", [CONTEXT_COURSECAT, 0]);
 196          $hiddencontexts = [];
 197          foreach ($records as $record) {
 198              context_helper::preload_from_record($record);
 199              $context = context::instance_by_id($record->id);
 200              if (!has_capability('moodle/category:viewhiddencategories', $context)) {
 201                  $hiddencontexts[] = $record->id;
 202              }
 203          }
 204          return $hiddencontexts;
 205      }
 206  
 207      /**
 208       * Returns parent file_info instance
 209       *
 210       * @return file_info|null file_info instance or null for root
 211       */
 212      public function get_parent() {
 213          return null;
 214      }
 215  }