cache/disabledlib.php

   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  * This file contains classes that are used by the Cache API only when it is disabled.
  19  *
  20  * These classes are derivatives of other significant classes used by the Cache API customised specifically
  21  * to only do what is absolutely necessary when initialising and using the Cache API when its been disabled.
  22  *
  23  * @package    core
  24  * @category   cache
  25  * @copyright  2012 Sam Hemelryk
  26  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  27  */
  28
  29 defined('MOODLE_INTERNAL') || die();
  30
  31 /**
  32  * Required as it is needed for cache_config_disabled which extends cache_config_writer.
  33  */
  34 require_once($CFG->dirroot.'/cache/locallib.php');
  35
  36 /**
  37  * The cache loader class used when the Cache has been disabled.
  38  *
  39  * @copyright  2012 Sam Hemelryk
  40  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  41  */
  42 class cache_disabled extends cache {
  43
  44     /**
  45      * Constructs the cache.
  46      *
  47      * @param cache_definition $definition
  48      * @param cache_store $store
  49      * @param null $loader Unused.
  50      */
  51     public function __construct(cache_definition $definition, cache_store $store, $loader = null) {
  52         if ($loader instanceof cache_data_source) {
  53             // Set the data source to allow data sources to work when caching is entirely disabled.
  54             $this->set_data_source($loader);
  55         }
  56
  57         // No other features are handled.
  58     }
  59
  60     /**
  61      * Gets a key from the cache.
  62      *
  63      * @param int|string $key
  64      * @param int $requiredversion Minimum required version of the data or cache::VERSION_NONE
  65      * @param int $strictness Unused.
  66      * @param mixed &$actualversion If specified, will be set to the actual version number retrieved
  67      * @return bool
  68      */
  69     protected function get_implementation($key, int $requiredversion, int $strictness, &$actualversion = null) {
  70         $datasource = $this->get_datasource();
  71         if ($datasource !== false) {
  72             if ($requiredversion === cache::VERSION_NONE) {
  73                 return $datasource->load_for_cache($key);
  74             } else {
  75                 if (!$datasource instanceof cache_data_source_versionable) {
  76                     throw new \coding_exception('Data source is not versionable');
  77                 }
  78                 $result = $datasource->load_for_cache_versioned($key, $requiredversion, $actualversion);
  79                 if ($result && $actualversion < $requiredversion) {
  80                     throw new \coding_exception('Data source returned outdated version');
  81                 }
  82                 return $result;
  83             }
  84         }
  85         return false;
  86     }
  87
  88     /**
  89      * Gets many keys at once from the cache.
  90      *
  91      * @param array $keys
  92      * @param int $strictness Unused.
  93      * @return array
  94      */
  95     public function get_many(array $keys, $strictness = IGNORE_MISSING) {
  96         if ($this->get_datasource() !== false) {
  97             return $this->get_datasource()->load_many_for_cache($keys);
  98         }
  99
 100         return array_combine($keys, array_fill(0, count($keys), false));
 101     }
 102
 103     /**
 104      * Sets a key value pair in the cache.
 105      *
 106      * @param int|string $key Unused.
 107      * @param int $version Unused.
 108      * @param mixed $data Unused.
 109      * @param bool $setparents Unused.
 110      * @return bool
 111      */
 112     protected function set_implementation($key, int $version, $data, bool $setparents = true): bool {
 113         return false;
 114     }
 115
 116     /**
 117      * Sets many key value pairs in the cache at once.
 118      *
 119      * @param array $keyvaluearray Unused.
 120      * @return int
 121      */
 122     public function set_many(array $keyvaluearray) {
 123         return 0;
 124     }
 125
 126     /**
 127      * Deletes an item from the cache.
 128      *
 129      * @param int|string $key Unused.
 130      * @param bool $recurse Unused.
 131      * @return bool
 132      */
 133     public function delete($key, $recurse = true) {
 134         return false;
 135     }
 136
 137     /**
 138      * Deletes many items at once from the cache.
 139      *
 140      * @param array $keys Unused.
 141      * @param bool $recurse Unused.
 142      * @return int
 143      */
 144     public function delete_many(array $keys, $recurse = true) {
 145         return 0;
 146     }
 147
 148     /**
 149      * Checks if the cache has the requested key.
 150      *
 151      * @param int|string $key Unused.
 152      * @param bool $tryloadifpossible Unused.
 153      * @return bool
 154      */
 155     public function has($key, $tryloadifpossible = false) {
 156         $result = $this->get($key);
 157
 158         return $result !== false;
 159     }
 160
 161     /**
 162      * Checks if the cache has all of the requested keys.
 163      * @param array $keys Unused.
 164      * @return bool
 165      */
 166     public function has_all(array $keys) {
 167         if (!$this->get_datasource()) {
 168             return false;
 169         }
 170
 171         foreach ($keys as $key) {
 172             if (!$this->has($key)) {
 173                 return false;
 174             }
 175         }
 176         return true;
 177     }
 178
 179     /**
 180      * Checks if the cache has any of the requested keys.
 181      *
 182      * @param array $keys Unused.
 183      * @return bool
 184      */
 185     public function has_any(array $keys) {
 186         foreach ($keys as $key) {
 187             if ($this->has($key)) {
 188                 return true;
 189             }
 190         }
 191
 192         return false;
 193     }
 194
 195     /**
 196      * Purges all items from the cache.
 197      *
 198      * @return bool
 199      */
 200     public function purge() {
 201         return true;
 202     }
 203
 204     /**
 205      * Pretend that we got a lock to avoid errors.
 206      *
 207      * @param string $key
 208      * @return bool
 209      */
 210     public function acquire_lock(string $key) : bool {
 211         return true;
 212     }
 213
 214     /**
 215      * Pretend that we released a lock to avoid errors.
 216      *
 217      * @param string $key
 218      * @return void
 219      */
 220     public function release_lock(string $key) : bool {
 221         return true;
 222     }
 223 }
 224
 225 /**
 226  * The cache factory class used when the Cache has been disabled.
 227  *
 228  * @copyright  2012 Sam Hemelryk
 229  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 230  */
 231 class cache_factory_disabled extends cache_factory {
 232     /** @var array Array of temporary caches in use. */
 233     protected static $tempcaches = [];
 234
 235     /**
 236      * Returns an instance of the cache_factor method.
 237      *
 238      * @param bool $forcereload Unused.
 239      * @return cache_factory
 240      * @throws coding_exception
 241      */
 242     public static function instance($forcereload = false) {
 243         throw new coding_exception('You must not call to this cache factory within your code.');
 244     }
 245
 246     /**
 247      * Creates a definition instance or returns the existing one if it has already been created.
 248      *
 249      * @param string $component
 250      * @param string $area
 251      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 252      * @return cache_definition
 253      */
 254     public function create_definition($component, $area, $unused = null) {
 255         $definition = parent::create_definition($component, $area);
 256         if ($definition->has_data_source()) {
 257             return $definition;
 258         }
 259
 260         return cache_definition::load_adhoc(cache_store::MODE_REQUEST, $component, $area);
 261     }
 262
 263     /**
 264      * Common public method to create a cache instance given a definition.
 265      *
 266      * @param cache_definition $definition
 267      * @return cache_application|cache_session|cache_store
 268      * @throws coding_exception
 269      */
 270     public function create_cache(cache_definition $definition) {
 271         $loader = null;
 272         if ($definition->has_data_source()) {
 273             $loader = $definition->get_data_source();
 274         }
 275         return new cache_disabled($definition, $this->create_dummy_store($definition), $loader);
 276     }
 277
 278     /**
 279      * Creates a cache object given the parameters for a definition.
 280      *
 281      * @param string $component
 282      * @param string $area
 283      * @param array $identifiers
 284      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 285      * @return cache_application|cache_session|cache_request
 286      */
 287     public function create_cache_from_definition($component, $area, array $identifiers = array(), $unused = null) {
 288         // Temporary in-memory caches are sometimes allowed when caching is disabled.
 289         if (\core_cache\allow_temporary_caches::is_allowed() && !$identifiers) {
 290             $key = $component . '/' . $area;
 291             if (array_key_exists($key, self::$tempcaches)) {
 292                 $cache = self::$tempcaches[$key];
 293             } else {
 294                 $definition = $this->create_definition($component, $area);
 295                 // The cachestore_static class returns true to all three 'SUPPORTS_' checks so it
 296                 // can be used with all definitions.
 297                 $cache = new cachestore_static('TEMP:' . $component . '/' . $area);
 298                 $cache->initialise($definition);
 299                 self::$tempcaches[$key] = $cache;
 300             }
 301             return $cache;
 302         }
 303
 304         // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php
 305         // definitions as they use load_adhoc().  They are built as a new object on each call.
 306         // We do not need to clone the definition because we know it's new.
 307         $definition = $this->create_definition($component, $area);
 308         $definition->set_identifiers($identifiers);
 309         $cache = $this->create_cache($definition);
 310         return $cache;
 311     }
 312
 313     /**
 314      * Removes all temporary caches.
 315      *
 316      * Don't call this directly - used by {@see \core_cache\allow_temporary_caches}.
 317      */
 318     public static function clear_temporary_caches(): void {
 319         self::$tempcaches = [];
 320     }
 321
 322     /**
 323      * Creates an ad-hoc cache from the given param.
 324      *
 325      * @param int $mode
 326      * @param string $component
 327      * @param string $area
 328      * @param array $identifiers
 329      * @param array $options An array of options, available options are:
 330      *   - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_
 331      *   - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars
 332      *   - staticacceleration : If set to true the cache will hold onto all data passing through it.
 333      *   - staticaccelerationsize : Sets the max size of the static acceleration array.
 334      * @return cache_application|cache_session|cache_request
 335      */
 336     public function create_cache_from_params($mode, $component, $area, array $identifiers = array(), array $options = array()) {
 337         // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php
 338         // definitions as they use load_adhoc().  They are built as a new object on each call.
 339         // We do not need to clone the definition because we know it's new.
 340         $definition = cache_definition::load_adhoc($mode, $component, $area, $options);
 341         $definition->set_identifiers($identifiers);
 342         $cache = $this->create_cache($definition);
 343         return $cache;
 344     }
 345
 346     /**
 347      * Creates a store instance given its name and configuration.
 348      *
 349      * @param string $name Unused.
 350      * @param array $details Unused.
 351      * @param cache_definition $definition
 352      * @return boolean|cache_store
 353      */
 354     public function create_store_from_config($name, array $details, cache_definition $definition) {
 355         return $this->create_dummy_store($definition);
 356     }
 357
 358     /**
 359      * Creates a cache config instance with the ability to write if required.
 360      *
 361      * @param bool $writer Unused.
 362      * @return cache_config_disabled|cache_config_writer
 363      */
 364     public function create_config_instance($writer = false) {
 365         // We are always going to use the cache_config_disabled class for all regular request.
 366         // However if the code has requested the writer then likely something is changing and
 367         // we're going to need to interact with the config.php file.
 368         // In this case we will still use the cache_config_writer.
 369         $class = 'cache_config_disabled';
 370         if ($writer) {
 371             // If the writer was requested then something is changing.
 372             $class = 'cache_config_writer';
 373         }
 374         if (!array_key_exists($class, $this->configs)) {
 375             self::set_state(self::STATE_INITIALISING);
 376             if ($class === 'cache_config_disabled') {
 377                 $configuration = $class::create_default_configuration();
 378                 $this->configs[$class] = new $class;
 379             } else {
 380                 $configuration = false;
 381                 // If we need a writer, we should get the classname from the generic factory.
 382                 // This is so alternative classes can be used if a different writer is required.
 383                 $this->configs[$class] = parent::get_disabled_writer();
 384             }
 385             $this->configs[$class]->load($configuration);
 386         }
 387         self::set_state(self::STATE_READY);
 388
 389         // Return the instance.
 390         return $this->configs[$class];
 391     }
 392
 393     /**
 394      * Returns true if the cache API has been disabled.
 395      *
 396      * @return bool
 397      */
 398     public function is_disabled() {
 399         return true;
 400     }
 401 }
 402
 403 /**
 404  * The cache config class used when the Cache has been disabled.
 405  *
 406  * @copyright  2012 Sam Hemelryk
 407  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 408  */
 409 class cache_config_disabled extends cache_config_writer {
 410
 411     /**
 412      * Returns an instance of the configuration writer.
 413      *
 414      * @return cache_config_disabled
 415      */
 416     public static function instance() {
 417         $factory = cache_factory::instance();
 418         return $factory->create_config_instance(true);
 419     }
 420
 421     /**
 422      * Saves the current configuration.
 423      */
 424     protected function config_save() {
 425         // Nothing to do here.
 426     }
 427
 428     /**
 429      * Generates a configuration array suitable to be written to the config file.
 430      *
 431      * @return array
 432      */
 433     protected function generate_configuration_array() {
 434         $configuration = array();
 435         $configuration['stores'] = $this->configstores;
 436         $configuration['modemappings'] = $this->configmodemappings;
 437         $configuration['definitions'] = $this->configdefinitions;
 438         $configuration['definitionmappings'] = $this->configdefinitionmappings;
 439         $configuration['locks'] = $this->configlocks;
 440         return $configuration;
 441     }
 442
 443     /**
 444      * Adds a plugin instance.
 445      *
 446      * @param string $name Unused.
 447      * @param string $plugin Unused.
 448      * @param array $configuration Unused.
 449      * @return bool
 450      * @throws cache_exception
 451      */
 452     public function add_store_instance($name, $plugin, array $configuration = array()) {
 453         return false;
 454     }
 455
 456     /**
 457      * Sets the mode mappings.
 458      *
 459      * @param array $modemappings Unused.
 460      * @return bool
 461      * @throws cache_exception
 462      */
 463     public function set_mode_mappings(array $modemappings) {
 464         return false;
 465     }
 466
 467     /**
 468      * Edits a give plugin instance.
 469      *
 470      * @param string $name Unused.
 471      * @param string $plugin Unused.
 472      * @param array $configuration Unused.
 473      * @return bool
 474      * @throws cache_exception
 475      */
 476     public function edit_store_instance($name, $plugin, $configuration) {
 477         return false;
 478     }
 479
 480     /**
 481      * Deletes a store instance.
 482      *
 483      * @param string $name Unused.
 484      * @return bool
 485      * @throws cache_exception
 486      */
 487     public function delete_store_instance($name) {
 488         return false;
 489     }
 490
 491     /**
 492      * Creates the default configuration and saves it.
 493      *
 494      * @param bool $forcesave Ignored because we are disabled!
 495      * @return array
 496      */
 497     public static function create_default_configuration($forcesave = false) {
 498         global $CFG;
 499
 500         // HACK ALERT.
 501         // We probably need to come up with a better way to create the default stores, or at least ensure 100% that the
 502         // default store plugins are protected from deletion.
 503         require_once($CFG->dirroot.'/cache/stores/file/lib.php');
 504         require_once($CFG->dirroot.'/cache/stores/session/lib.php');
 505         require_once($CFG->dirroot.'/cache/stores/static/lib.php');
 506
 507         $writer = new self;
 508         $writer->configstores = array(
 509             'default_application' => array(
 510                 'name' => 'default_application',
 511                 'plugin' => 'file',
 512                 'configuration' => array(),
 513                 'features' => cachestore_file::get_supported_features(),
 514                 'modes' => cache_store::MODE_APPLICATION,
 515                 'default' => true,
 516             ),
 517             'default_session' => array(
 518                 'name' => 'default_session',
 519                 'plugin' => 'session',
 520                 'configuration' => array(),
 521                 'features' => cachestore_session::get_supported_features(),
 522                 'modes' => cache_store::MODE_SESSION,
 523                 'default' => true,
 524             ),
 525             'default_request' => array(
 526                 'name' => 'default_request',
 527                 'plugin' => 'static',
 528                 'configuration' => array(),
 529                 'features' => cachestore_static::get_supported_features(),
 530                 'modes' => cache_store::MODE_REQUEST,
 531                 'default' => true,
 532             )
 533         );
 534         $writer->configdefinitions = array();
 535         $writer->configmodemappings = array(
 536             array(
 537                 'mode' => cache_store::MODE_APPLICATION,
 538                 'store' => 'default_application',
 539                 'sort' => -1
 540             ),
 541             array(
 542                 'mode' => cache_store::MODE_SESSION,
 543                 'store' => 'default_session',
 544                 'sort' => -1
 545             ),
 546             array(
 547                 'mode' => cache_store::MODE_REQUEST,
 548                 'store' => 'default_request',
 549                 'sort' => -1
 550             )
 551         );
 552         $writer->configlocks = array(
 553             'default_file_lock' => array(
 554                 'name' => 'cachelock_file_default',
 555                 'type' => 'cachelock_file',
 556                 'dir' => 'filelocks',
 557                 'default' => true
 558             )
 559         );
 560
 561         return $writer->generate_configuration_array();
 562     }
 563
 564     /**
 565      * Updates the definition in the configuration from those found in the cache files.
 566      *
 567      * @param bool $coreonly Unused.
 568      */
 569     public static function update_definitions($coreonly = false) {
 570         // Nothing to do here.
 571     }
 572
 573     /**
 574      * Locates all of the definition files.
 575      *
 576      * @param bool $coreonly Unused.
 577      * @return array
 578      */
 579     protected static function locate_definitions($coreonly = false) {
 580         return array();
 581     }
 582
 583     /**
 584      * Sets the mappings for a given definition.
 585      *
 586      * @param string $definition Unused.
 587      * @param array $mappings Unused.
 588      * @throws coding_exception
 589      */
 590     public function set_definition_mappings($definition, $mappings) {
 591         // Nothing to do here.
 592     }
 593 }