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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 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  require_once("$CFG->libdir/filebrowser/file_info.php");
  29  
  30  // general area types
  31  require_once("$CFG->libdir/filebrowser/file_info_stored.php");
  32  require_once("$CFG->libdir/filebrowser/virtual_root_file.php");
  33  
  34  // description of available areas in each context level
  35  require_once("$CFG->libdir/filebrowser/file_info_context_system.php");
  36  require_once("$CFG->libdir/filebrowser/file_info_context_user.php");
  37  require_once("$CFG->libdir/filebrowser/file_info_context_coursecat.php");
  38  require_once("$CFG->libdir/filebrowser/file_info_context_course.php");
  39  require_once("$CFG->libdir/filebrowser/file_info_context_module.php");
  40  
  41  /**
  42   * This class provides the main entry point for other code wishing to get information about files.
  43   *
  44   * The whole file storage for a Moodle site can be seen as a huge virtual tree.
  45   * The spine of the tree is the tree of contexts (system, course-categories,
  46   * courses, modules, also users). Then, within each context, there may be any number of
  47   * file areas, and a file area contains folders and files. The various file_info
  48   * subclasses return info about the things in this tree. They should be obtained
  49   * from an instance of this class.
  50   *
  51   * This virtual tree is different for each user depending of his/her current permissions.
  52   * Some branches such as draft areas are hidden, but accessible.
  53   *
  54   * Always use this abstraction when you need to access module files from core code.
  55    *
  56   * @package   core_files
  57   * @category  files
  58   * @copyright 2008 Petr Skoda (http://skodak.org)
  59   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  60  */
  61  class file_browser {
  62  
  63      /**
  64       * Looks up file_info instance
  65       *
  66       * @param stdClass $context context object
  67       * @param string $component component
  68       * @param string $filearea file area
  69       * @param int $itemid item ID
  70       * @param string $filepath file path
  71       * @param string $filename file name
  72       * @return file_info|null file_info instance or null if not found or access not allowed
  73       */
  74      public function get_file_info($context = NULL, $component = NULL, $filearea = NULL, $itemid = NULL, $filepath = NULL, $filename = NULL) {
  75          if (!$context) {
  76              $context = context_system::instance();
  77          }
  78          switch ($context->contextlevel) {
  79              case CONTEXT_SYSTEM:
  80                  return $this->get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename);
  81              case CONTEXT_USER:
  82                  return $this->get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename);
  83              case CONTEXT_COURSECAT:
  84                  return $this->get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename);
  85              case CONTEXT_COURSE:
  86                  return $this->get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename);
  87              case CONTEXT_MODULE:
  88                  return $this->get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename);
  89          }
  90  
  91          return null;
  92      }
  93  
  94      /**
  95       * Returns info about the files at System context
  96       * @todo MDL-33372 - Provide a way of displaying recent files for blog entries.
  97       *
  98       * @param object $context context object
  99       * @param string $component component
 100       * @param string $filearea file area
 101       * @param int $itemid item ID
 102       * @param string $filepath file path
 103       * @param string $filename file name
 104       * @return file_info instance or null if not found or access not allowed
 105       */
 106      private function get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename) {
 107          $level = new file_info_context_system($this, $context);
 108          return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 109          // nothing supported at this context yet
 110      }
 111  
 112      /**
 113       * Returns info about the files at User context
 114       *
 115       * @param stdClass $context context object
 116       * @param string $component component
 117       * @param string $filearea file area
 118       * @param int $itemid item ID
 119       * @param string $filepath file path
 120       * @param string $filename file name
 121       * @return file_info|null file_info instance or null if not found or access not allowed
 122       */
 123      private function get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename) {
 124          global $DB, $USER;
 125          if ($context->instanceid == $USER->id) {
 126              $user = $USER;
 127          } else {
 128              $user = $DB->get_record('user', array('id'=>$context->instanceid));
 129          }
 130  
 131          if (isguestuser($user)) {
 132              // guests do not have any files
 133              return null;
 134          }
 135  
 136          if ($user->deleted) {
 137              return null;
 138          }
 139  
 140          $level = new file_info_context_user($this, $context, $user);
 141          return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 142      }
 143  
 144      /**
 145       * Returns info about the files at Course category context
 146       *
 147       * @param stdClass $context context object
 148       * @param string $component component
 149       * @param string $filearea file area
 150       * @param int $itemid item ID
 151       * @param string $filepath file path
 152       * @param string $filename file name
 153       * @return file_info|null file_info instance or null if not found or access not allowed
 154       */
 155      private function get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename) {
 156          global $DB;
 157  
 158          if (!$category = $DB->get_record('course_categories', array('id'=>$context->instanceid))) {
 159              return null;
 160          }
 161  
 162          $level = new file_info_context_coursecat($this, $context, $category);
 163          return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 164      }
 165  
 166      /**
 167       * Returns info about the files at Course category context
 168       *
 169       * @param stdClass $context context object
 170       * @param string $component component
 171       * @param string $filearea file area
 172       * @param int $itemid item ID
 173       * @param string $filepath file path
 174       * @param string $filename file name
 175       * @return file_info|null file_info instance or null if not found or access not allowed
 176       */
 177      private function get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename) {
 178          global $DB, $COURSE;
 179  
 180          if ($context->instanceid == $COURSE->id) {
 181              $course = $COURSE;
 182          } else if (!$course = $DB->get_record('course', array('id'=>$context->instanceid))) {
 183              return null;
 184          }
 185  
 186          $level = new file_info_context_course($this, $context, $course);
 187          return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 188      }
 189  
 190      /**
 191       * Returns info about the files at Course category context
 192       *
 193       * @param stdClass $context context object
 194       * @param string $component component
 195       * @param string $filearea file area
 196       * @param int $itemid item ID
 197       * @param string $filepath file path
 198       * @param string $filename file name
 199       * @return file_info|null file_info instance or null if not found or access not allowed
 200       */
 201      private function get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename) {
 202          global $COURSE, $DB, $CFG;
 203  
 204          static $cachedmodules = array();
 205  
 206          if (!array_key_exists($context->instanceid, $cachedmodules)) {
 207              $cachedmodules[$context->instanceid] = get_coursemodule_from_id('', $context->instanceid);
 208          }
 209  
 210          if (!($cm = $cachedmodules[$context->instanceid])) {
 211              return null;
 212          }
 213  
 214          if ($cm->course == $COURSE->id) {
 215              $course = $COURSE;
 216          } else if (!$course = $DB->get_record('course', array('id'=>$cm->course))) {
 217              return null;
 218          }
 219  
 220          $modinfo = get_fast_modinfo($course);
 221          if (empty($modinfo->cms[$cm->id]->uservisible)) {
 222              return null;
 223          }
 224  
 225          $modname = $modinfo->cms[$cm->id]->modname;
 226  
 227          if (!file_exists("$CFG->dirroot/mod/$modname/lib.php")) {
 228              return null;
 229          }
 230  
 231          // ok, we know that module exists, and user may access it
 232  
 233          $level = new file_info_context_module($this, $context, $course, $cm, $modname);
 234          return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);
 235      }
 236  
 237  }