[Summary view]

Differences Between: [Versions 39 and 401]

   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   * The supplementary cache API.
  19   *
  20   * This file is part of Moodle's cache API, affectionately called MUC.
  21   * It contains elements of the API that are not required in order to use caching.
  22   * Things in here are more in line with administration and management of the cache setup and configuration.
  23   *
  24   * @package    core
  25   * @category   cache
  26   * @copyright  2012 Sam Hemelryk
  27   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  28   */
  29  
  30  defined('MOODLE_INTERNAL') || die();
  31  
  32  /**
  33   * Cache configuration writer.
  34   *
  35   * This class should only be used when you need to write to the config, all read operations exist within the cache_config.
  36   *
  37   * @package    core
  38   * @category   cache
  39   * @copyright  2012 Sam Hemelryk
  40   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  41   */
  42  class cache_config_writer extends cache_config {
  43  
  44      /**
  45       * Switch that gets set to true when ever a cache_config_writer instance is saving the cache configuration file.
  46       * If this is set to true when save is next called we must avoid the trying to save and instead return the
  47       * generated config so that is may be used instead of the file.
  48       * @var bool
  49       */
  50      protected static $creatingconfig = false;
  51  
  52      /**
  53       * Returns an instance of the configuration writer.
  54       *
  55       * @return cache_config_writer
  56       */
  57      public static function instance() {
  58          $factory = cache_factory::instance();
  59          return $factory->create_config_instance(true);
  60      }
  61  
  62      /**
  63       * Saves the current configuration.
  64       *
  65       * Exceptions within this function are tolerated but must be of type cache_exception.
  66       * They are caught during initialisation and written to the error log. This is required in order to avoid
  67       * infinite loop situations caused by the cache throwing exceptions during its initialisation.
  68       */
  69      protected function config_save() {
  70          global $CFG;
  71          static $confighash = '';
  72          $cachefile = static::get_config_file_path();
  73          $directory = dirname($cachefile);
  74          if ($directory !== $CFG->dataroot && !file_exists($directory)) {
  75              $result = make_writable_directory($directory, false);
  76              if (!$result) {
  77                  throw new cache_exception('ex_configcannotsave', 'cache', '', null, 'Cannot create config directory. Check the permissions on your moodledata directory.');
  78              }
  79          }
  80          if (!file_exists($directory) || !is_writable($directory)) {
  81              throw new cache_exception('ex_configcannotsave', 'cache', '', null, 'Config directory is not writable. Check the permissions on the moodledata/muc directory.');
  82          }
  83  
  84          // Prepare a configuration array to store.
  85          $configuration = $this->generate_configuration_array();
  86  
  87          // Prepare the file content.
  88          $content = "<?php defined('MOODLE_INTERNAL') || die();\n \$configuration = ".var_export($configuration, true).";";
  89  
  90          // Do both file content and hash based detection because this might be called
  91          // many times within a single request.
  92          $hash = sha1($content);
  93          if (($hash === $confighash) || (file_exists($cachefile) && $content === file_get_contents($cachefile))) {
  94              // Config is unchanged so don't bother locking and writing.
  95              $confighash = $hash;
  96              return;
  97          }
  98  
  99          // We need to create a temporary cache lock instance for use here. Remember we are generating the config file
 100          // it doesn't exist and thus we can't use the normal API for this (it'll just try to use config).
 101          $lockconf = reset($this->configlocks);
 102          if ($lockconf === false) {
 103              debugging('Your cache configuration file is out of date and needs to be refreshed.', DEBUG_DEVELOPER);
 104              // Use the default
 105              $lockconf = array(
 106                  'name' => 'cachelock_file_default',
 107                  'type' => 'cachelock_file',
 108                  'dir' => 'filelocks',
 109                  'default' => true
 110              );
 111          }
 112          $factory = cache_factory::instance();
 113          $locking = $factory->create_lock_instance($lockconf);
 114          if ($locking->lock('configwrite', 'config', true)) {
 115              $tempcachefile = "{$cachefile}.tmp";
 116              // Its safe to use w mode here because we have already acquired the lock.
 117              $handle = fopen($tempcachefile, 'w');
 118              fwrite($handle, $content);
 119              fflush($handle);
 120              fclose($handle);
 121              $locking->unlock('configwrite', 'config');
 122              @chmod($tempcachefile, $CFG->filepermissions);
 123              rename($tempcachefile, $cachefile);
 124              // Tell PHP to recompile the script.
 125              core_component::invalidate_opcode_php_cache($cachefile);
 126          } else {
 127              throw new cache_exception('ex_configcannotsave', 'cache', '', null, 'Unable to open the cache config file.');
 128          }
 129      }
 130  
 131      /**
 132       * Generates a configuration array suitable to be written to the config file.
 133       * @return array
 134       */
 135      protected function generate_configuration_array() {
 136          $configuration = array();
 137          $configuration['siteidentifier'] = $this->siteidentifier;
 138          $configuration['stores'] = $this->configstores;
 139          $configuration['modemappings'] = $this->configmodemappings;
 140          $configuration['definitions'] = $this->configdefinitions;
 141          $configuration['definitionmappings'] = $this->configdefinitionmappings;
 142          $configuration['locks'] = $this->configlocks;
 143          return $configuration;
 144      }
 145  
 146      /**
 147       * Adds a plugin instance.
 148       *
 149       * This function also calls save so you should redirect immediately, or at least very shortly after
 150       * calling this method.
 151       *
 152       * @param string $name The name for the instance (must be unique)
 153       * @param string $plugin The name of the plugin.
 154       * @param array $configuration The configuration data for the plugin instance.
 155       * @return bool
 156       * @throws cache_exception
 157       */
 158      public function add_store_instance($name, $plugin, array $configuration = array()) {
 159          if (array_key_exists($name, $this->configstores)) {
 160              throw new cache_exception('Duplicate name specificed for cache plugin instance. You must provide a unique name.');
 161          }
 162          $class = 'cachestore_'.$plugin;
 163          if (!class_exists($class)) {
 164              $plugins = core_component::get_plugin_list_with_file('cachestore', 'lib.php');
 165              if (!array_key_exists($plugin, $plugins)) {
 166                  throw new cache_exception('Invalid plugin name specified. The plugin does not exist or is not valid.');
 167              }
 168              $file = $plugins[$plugin];
 169              if (file_exists($file)) {
 170                  require_once($file);
 171              }
 172              if (!class_exists($class)) {
 173                  throw new cache_exception('Invalid cache plugin specified. The plugin does not contain the required class.');
 174              }
 175          }
 176          $reflection = new ReflectionClass($class);
 177          if (!$reflection->isSubclassOf('cache_store')) {
 178              throw new cache_exception('Invalid cache plugin specified. The plugin does not extend the required class.');
 179          }
 180          if (!$class::are_requirements_met()) {
 181              throw new cache_exception('Unable to add new cache plugin instance. The requested plugin type is not supported.');
 182          }
 183          $this->configstores[$name] = array(
 184              'name' => $name,
 185              'plugin' => $plugin,
 186              'configuration' => $configuration,
 187              'features' => $class::get_supported_features($configuration),
 188              'modes' => $class::get_supported_modes($configuration),
 189              'mappingsonly' => !empty($configuration['mappingsonly']),
 190              'class' => $class,
 191              'default' => false
 192          );
 193          if (array_key_exists('lock', $configuration)) {
 194              $this->configstores[$name]['lock'] = $configuration['lock'];
 195              unset($this->configstores[$name]['configuration']['lock']);
 196          }
 197          // Call instance_created()
 198          $store = new $class($name, $this->configstores[$name]['configuration']);
 199          $store->instance_created();
 200  
 201          $this->config_save();
 202          return true;
 203      }
 204  
 205      /**
 206       * Adds a new lock instance to the config file.
 207       *
 208       * @param string $name The name the user gave the instance. PARAM_ALHPANUMEXT
 209       * @param string $plugin The plugin we are creating an instance of.
 210       * @param string $configuration Configuration data from the config instance.
 211       * @throws cache_exception
 212       */
 213      public function add_lock_instance($name, $plugin, $configuration = array()) {
 214          if (array_key_exists($name, $this->configlocks)) {
 215              throw new cache_exception('Duplicate name specificed for cache lock instance. You must provide a unique name.');
 216          }
 217          $class = 'cachelock_'.$plugin;
 218          if (!class_exists($class)) {
 219              $plugins = core_component::get_plugin_list_with_file('cachelock', 'lib.php');
 220              if (!array_key_exists($plugin, $plugins)) {
 221                  throw new cache_exception('Invalid lock name specified. The plugin does not exist or is not valid.');
 222              }
 223              $file = $plugins[$plugin];
 224              if (file_exists($file)) {
 225                  require_once($file);
 226              }
 227              if (!class_exists($class)) {
 228                  throw new cache_exception('Invalid lock plugin specified. The plugin does not contain the required class.');
 229              }
 230          }
 231          $reflection = new ReflectionClass($class);
 232          if (!$reflection->implementsInterface('cache_lock_interface')) {
 233              throw new cache_exception('Invalid lock plugin specified. The plugin does not implement the required interface.');
 234          }
 235          $this->configlocks[$name] = array_merge($configuration, array(
 236              'name' => $name,
 237              'type' => 'cachelock_'.$plugin,
 238              'default' => false
 239          ));
 240          $this->config_save();
 241      }
 242  
 243      /**
 244       * Deletes a lock instance given its name.
 245       *
 246       * @param string $name The name of the plugin, PARAM_ALPHANUMEXT.
 247       * @return bool
 248       * @throws cache_exception
 249       */
 250      public function delete_lock_instance($name) {
 251          if (!array_key_exists($name, $this->configlocks)) {
 252              throw new cache_exception('The requested store does not exist.');
 253          }
 254          if ($this->configlocks[$name]['default']) {
 255              throw new cache_exception('You can not delete the default lock.');
 256          }
 257          foreach ($this->configstores as $store) {
 258              if (isset($store['lock']) && $store['lock'] === $name) {
 259                  throw new cache_exception('You cannot delete a cache lock that is being used by a store.');
 260              }
 261          }
 262          unset($this->configlocks[$name]);
 263          $this->config_save();
 264          return true;
 265      }
 266  
 267      /**
 268       * Sets the mode mappings.
 269       *
 270       * These determine the default caches for the different modes.
 271       * This function also calls save so you should redirect immediately, or at least very shortly after
 272       * calling this method.
 273       *
 274       * @param array $modemappings
 275       * @return bool
 276       * @throws cache_exception
 277       */
 278      public function set_mode_mappings(array $modemappings) {
 279          $mappings = array(
 280              cache_store::MODE_APPLICATION => array(),
 281              cache_store::MODE_SESSION => array(),
 282              cache_store::MODE_REQUEST => array(),
 283          );
 284          foreach ($modemappings as $mode => $stores) {
 285              if (!array_key_exists($mode, $mappings)) {
 286                  throw new cache_exception('The cache mode for the new mapping does not exist');
 287              }
 288              $sort = 0;
 289              foreach ($stores as $store) {
 290                  if (!array_key_exists($store, $this->configstores)) {
 291                      throw new cache_exception('The instance name for the new mapping does not exist');
 292                  }
 293                  if (array_key_exists($store, $mappings[$mode])) {
 294                      throw new cache_exception('This cache mapping already exists');
 295                  }
 296                  $mappings[$mode][] = array(
 297                      'store' => $store,
 298                      'mode' => $mode,
 299                      'sort' => $sort++
 300                  );
 301              }
 302          }
 303          $this->configmodemappings = array_merge(
 304              $mappings[cache_store::MODE_APPLICATION],
 305              $mappings[cache_store::MODE_SESSION],
 306              $mappings[cache_store::MODE_REQUEST]
 307          );
 308  
 309          $this->config_save();
 310          return true;
 311      }
 312  
 313      /**
 314       * Edits a give plugin instance.
 315       *
 316       * The plugin instance is determined by its name, hence you cannot rename plugins.
 317       * This function also calls save so you should redirect immediately, or at least very shortly after
 318       * calling this method.
 319       *
 320       * @param string $name
 321       * @param string $plugin
 322       * @param array $configuration
 323       * @return bool
 324       * @throws cache_exception
 325       */
 326      public function edit_store_instance($name, $plugin, $configuration) {
 327          if (!array_key_exists($name, $this->configstores)) {
 328              throw new cache_exception('The requested instance does not exist.');
 329          }
 330          $plugins = core_component::get_plugin_list_with_file('cachestore', 'lib.php');
 331          if (!array_key_exists($plugin, $plugins)) {
 332              throw new cache_exception('Invalid plugin name specified. The plugin either does not exist or is not valid.');
 333          }
 334          $class = 'cachestore_'.$plugin;
 335          $file = $plugins[$plugin];
 336          if (!class_exists($class)) {
 337              if (file_exists($file)) {
 338                  require_once($file);
 339              }
 340              if (!class_exists($class)) {
 341                  throw new cache_exception('Invalid cache plugin specified. The plugin does not contain the required class.'.$class);
 342              }
 343          }
 344          $this->configstores[$name] = array(
 345              'name' => $name,
 346              'plugin' => $plugin,
 347              'configuration' => $configuration,
 348              'features' => $class::get_supported_features($configuration),
 349              'modes' => $class::get_supported_modes($configuration),
 350              'mappingsonly' => !empty($configuration['mappingsonly']),
 351              'class' => $class,
 352              'default' => $this->configstores[$name]['default'] // Can't change the default.
 353          );
 354          if (array_key_exists('lock', $configuration)) {
 355              $this->configstores[$name]['lock'] = $configuration['lock'];
 356              unset($this->configstores[$name]['configuration']['lock']);
 357          }
 358          $this->config_save();
 359          return true;
 360      }
 361  
 362      /**
 363       * Deletes a store instance.
 364       *
 365       * This function also calls save so you should redirect immediately, or at least very shortly after
 366       * calling this method.
 367       *
 368       * @param string $name The name of the instance to delete.
 369       * @return bool
 370       * @throws cache_exception
 371       */
 372      public function delete_store_instance($name) {
 373          if (!array_key_exists($name, $this->configstores)) {
 374              throw new cache_exception('The requested store does not exist.');
 375          }
 376          if ($this->configstores[$name]['default']) {
 377              throw new cache_exception('The can not delete the default stores.');
 378          }
 379          foreach ($this->configmodemappings as $mapping) {
 380              if ($mapping['store'] === $name) {
 381                  throw new cache_exception('You cannot delete a cache store that has mode mappings.');
 382              }
 383          }
 384          foreach ($this->configdefinitionmappings as $mapping) {
 385              if ($mapping['store'] === $name) {
 386                  throw new cache_exception('You cannot delete a cache store that has definition mappings.');
 387              }
 388          }
 389  
 390          // Call instance_deleted()
 391          $class = 'cachestore_'.$this->configstores[$name]['plugin'];
 392          $store = new $class($name, $this->configstores[$name]['configuration']);
 393          $store->instance_deleted();
 394  
 395          unset($this->configstores[$name]);
 396          $this->config_save();
 397          return true;
 398      }
 399  
 400      /**
 401       * Creates the default configuration and saves it.
 402       *
 403       * This function calls config_save, however it is safe to continue using it afterwards as this function should only ever
 404       * be called when there is no configuration file already.
 405       *
 406       * @param bool $forcesave If set to true then we will forcefully save the default configuration file.
 407       * @return true|array Returns true if the default configuration was successfully created.
 408       *     Returns a configuration array if it could not be saved. This is a bad situation. Check your error logs.
 409       */
 410      public static function create_default_configuration($forcesave = false) {
 411          // HACK ALERT.
 412          // We probably need to come up with a better way to create the default stores, or at least ensure 100% that the
 413          // default store plugins are protected from deletion.
 414          $writer = new self;
 415          $writer->configstores = self::get_default_stores();
 416          $writer->configdefinitions = self::locate_definitions();
 417          $writer->configmodemappings = array(
 418              array(
 419                  'mode' => cache_store::MODE_APPLICATION,
 420                  'store' => 'default_application',
 421                  'sort' => -1
 422              ),
 423              array(
 424                  'mode' => cache_store::MODE_SESSION,
 425                  'store' => 'default_session',
 426                  'sort' => -1
 427              ),
 428              array(
 429                  'mode' => cache_store::MODE_REQUEST,
 430                  'store' => 'default_request',
 431                  'sort' => -1
 432              )
 433          );
 434          $writer->configlocks = array(
 435              'default_file_lock' => array(
 436                  'name' => 'cachelock_file_default',
 437                  'type' => 'cachelock_file',
 438                  'dir' => 'filelocks',
 439                  'default' => true
 440              )
 441          );
 442  
 443          $factory = cache_factory::instance();
 444          // We expect the cache to be initialising presently. If its not then something has gone wrong and likely
 445          // we are now in a loop.
 446          if (!$forcesave && $factory->get_state() !== cache_factory::STATE_INITIALISING) {
 447              return $writer->generate_configuration_array();
 448          }
 449          $factory->set_state(cache_factory::STATE_SAVING);
 450          $writer->config_save();
 451          return true;
 452      }
 453  
 454      /**
 455       * Returns an array of default stores for use.
 456       *
 457       * @return array
 458       */
 459      protected static function get_default_stores() {
 460          global $CFG;
 461  
 462          require_once($CFG->dirroot.'/cache/stores/file/lib.php');
 463          require_once($CFG->dirroot.'/cache/stores/session/lib.php');
 464          require_once($CFG->dirroot.'/cache/stores/static/lib.php');
 465  
 466          return array(
 467              'default_application' => array(
 468                  'name' => 'default_application',
 469                  'plugin' => 'file',
 470                  'configuration' => array(),
 471                  'features' => cachestore_file::get_supported_features(),
 472                  'modes' => cachestore_file::get_supported_modes(),
 473                  'default' => true,
 474              ),
 475              'default_session' => array(
 476                  'name' => 'default_session',
 477                  'plugin' => 'session',
 478                  'configuration' => array(),
 479                  'features' => cachestore_session::get_supported_features(),
 480                  'modes' => cachestore_session::get_supported_modes(),
 481                  'default' => true,
 482              ),
 483              'default_request' => array(
 484                  'name' => 'default_request',
 485                  'plugin' => 'static',
 486                  'configuration' => array(),
 487                  'features' => cachestore_static::get_supported_features(),
 488                  'modes' => cachestore_static::get_supported_modes(),
 489                  'default' => true,
 490              )
 491          );
 492      }
 493  
 494      /**
 495       * Updates the default stores within the MUC config file.
 496       */
 497      public static function update_default_config_stores() {
 498          $factory = cache_factory::instance();
 499          $factory->updating_started();
 500          $config = $factory->create_config_instance(true);
 501          $config->configstores = array_merge($config->configstores, self::get_default_stores());
 502          $config->config_save();
 503          $factory->updating_finished();
 504      }
 505  
 506      /**
 507       * Updates the definition in the configuration from those found in the cache files.
 508       *
 509       * Calls config_save further down, you should redirect immediately or asap after calling this method.
 510       *
 511       * @param bool $coreonly If set to true only core definitions will be updated.
 512       */
 513      public static function update_definitions($coreonly = false) {
 514          $factory = cache_factory::instance();
 515          $factory->updating_started();
 516          $config = $factory->create_config_instance(true);
 517          $config->write_definitions_to_cache(self::locate_definitions($coreonly));
 518          $factory->updating_finished();
 519      }
 520  
 521      /**
 522       * Locates all of the definition files.
 523       *
 524       * @param bool $coreonly If set to true only core definitions will be updated.
 525       * @return array
 526       */
 527      protected static function locate_definitions($coreonly = false) {
 528          global $CFG;
 529  
 530          $files = array();
 531          if (file_exists($CFG->dirroot.'/lib/db/caches.php')) {
 532              $files['core'] = $CFG->dirroot.'/lib/db/caches.php';
 533          }
 534  
 535          if (!$coreonly) {
 536              $plugintypes = core_component::get_plugin_types();
 537              foreach ($plugintypes as $type => $location) {
 538                  $plugins = core_component::get_plugin_list_with_file($type, 'db/caches.php');
 539                  foreach ($plugins as $plugin => $filepath) {
 540                      $component = clean_param($type.'_'.$plugin, PARAM_COMPONENT); // Standardised plugin name.
 541                      $files[$component] = $filepath;
 542                  }
 543              }
 544          }
 545  
 546          $definitions = array();
 547          foreach ($files as $component => $file) {
 548              $filedefs = self::load_caches_file($file);
 549              foreach ($filedefs as $area => $definition) {
 550                  $area = clean_param($area, PARAM_AREA);
 551                  $id = $component.'/'.$area;
 552                  $definition['component'] = $component;
 553                  $definition['area'] = $area;
 554                  if (array_key_exists($id, $definitions)) {
 555                      debugging('Error: duplicate cache definition found with id: '.$id, DEBUG_DEVELOPER);
 556                      continue;
 557                  }
 558                  $definitions[$id] = $definition;
 559              }
 560          }
 561  
 562          return $definitions;
 563      }
 564  
 565      /**
 566       * Writes the updated definitions for the config file.
 567       * @param array $definitions
 568       */
 569      private function write_definitions_to_cache(array $definitions) {
 570  
 571          // Preserve the selected sharing option when updating the definitions.
 572          // This is set by the user and should never come from caches.php.
 573          foreach ($definitions as $key => $definition) {
 574              unset($definitions[$key]['selectedsharingoption']);
 575              unset($definitions[$key]['userinputsharingkey']);
 576              if (isset($this->configdefinitions[$key]) && isset($this->configdefinitions[$key]['selectedsharingoption'])) {
 577                  $definitions[$key]['selectedsharingoption'] = $this->configdefinitions[$key]['selectedsharingoption'];
 578              }
 579              if (isset($this->configdefinitions[$key]) && isset($this->configdefinitions[$key]['userinputsharingkey'])) {
 580                  $definitions[$key]['userinputsharingkey'] = $this->configdefinitions[$key]['userinputsharingkey'];
 581              }
 582          }
 583  
 584          $this->configdefinitions = $definitions;
 585          foreach ($this->configdefinitionmappings as $key => $mapping) {
 586              if (!array_key_exists($mapping['definition'], $definitions)) {
 587                  unset($this->configdefinitionmappings[$key]);
 588              }
 589          }
 590          $this->config_save();
 591      }
 592  
 593      /**
 594       * Loads the caches file if it exists.
 595       * @param string $file Absolute path to the file.
 596       * @return array
 597       */
 598      private static function load_caches_file($file) {
 599          if (!file_exists($file)) {
 600              return array();
 601          }
 602          $definitions = array();
 603          include($file);
 604          return $definitions;
 605      }
 606  
 607      /**
 608       * Sets the mappings for a given definition.
 609       *
 610       * @param string $definition
 611       * @param array $mappings
 612       * @throws coding_exception
 613       */
 614      public function set_definition_mappings($definition, $mappings) {
 615          if (!array_key_exists($definition, $this->configdefinitions)) {
 616              throw new coding_exception('Invalid definition name passed when updating mappings.');
 617          }
 618          foreach ($mappings as $store) {
 619              if (!array_key_exists($store, $this->configstores)) {
 620                  throw new coding_exception('Invalid store name passed when updating definition mappings.');
 621              }
 622          }
 623          foreach ($this->configdefinitionmappings as $key => $mapping) {
 624              if ($mapping['definition'] == $definition) {
 625                  unset($this->configdefinitionmappings[$key]);
 626              }
 627          }
 628          $sort = count($mappings);
 629          foreach ($mappings as $store) {
 630              $this->configdefinitionmappings[] = array(
 631                  'store' => $store,
 632                  'definition' => $definition,
 633                  'sort' => $sort
 634              );
 635              $sort--;
 636          }
 637  
 638          $this->config_save();
 639      }
 640  
 641      /**
 642       * Update the site identifier stored by the cache API.
 643       *
 644       * @param string $siteidentifier
 645       * @return string The new site identifier.
 646       */
 647      public function update_site_identifier($siteidentifier) {
 648          $this->siteidentifier = md5((string)$siteidentifier);
 649          $this->config_save();
 650          return $this->siteidentifier;
 651      }
 652  
 653      /**
 654       * Sets the selected sharing options and key for a definition.
 655       *
 656       * @param string $definition The name of the definition to set for.
 657       * @param int $sharingoption The sharing option to set.
 658       * @param string|null $userinputsharingkey The user input key or null.
 659       * @throws coding_exception
 660       */
 661      public function set_definition_sharing($definition, $sharingoption, $userinputsharingkey = null) {
 662          if (!array_key_exists($definition, $this->configdefinitions)) {
 663              throw new coding_exception('Invalid definition name passed when updating sharing options.');
 664          }
 665          if (!($this->configdefinitions[$definition]['sharingoptions'] & $sharingoption)) {
 666              throw new coding_exception('Invalid sharing option passed when updating definition.');
 667          }
 668          $this->configdefinitions[$definition]['selectedsharingoption'] = (int)$sharingoption;
 669          if (!empty($userinputsharingkey)) {
 670              $this->configdefinitions[$definition]['userinputsharingkey'] = (string)$userinputsharingkey;
 671          }
 672          $this->config_save();
 673      }
 674  }