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 /**
 206  * The cache factory class used when the Cache has been disabled.
 207  *
 208  * @copyright  2012 Sam Hemelryk
 209  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 210  */
 211 class cache_factory_disabled extends cache_factory {
 212
 213     /**
 214      * Returns an instance of the cache_factor method.
 215      *
 216      * @param bool $forcereload Unused.
 217      * @return cache_factory
 218      * @throws coding_exception
 219      */
 220     public static function instance($forcereload = false) {
 221         throw new coding_exception('You must not call to this cache factory within your code.');
 222     }
 223
 224     /**
 225      * Creates a definition instance or returns the existing one if it has already been created.
 226      *
 227      * @param string $component
 228      * @param string $area
 229      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 230      * @return cache_definition
 231      */
 232     public function create_definition($component, $area, $unused = null) {
 233         $definition = parent::create_definition($component, $area);
 234         if ($definition->has_data_source()) {
 235             return $definition;
 236         }
 237
 238         return cache_definition::load_adhoc(cache_store::MODE_REQUEST, $component, $area);
 239     }
 240
 241     /**
 242      * Common public method to create a cache instance given a definition.
 243      *
 244      * @param cache_definition $definition
 245      * @return cache_application|cache_session|cache_store
 246      * @throws coding_exception
 247      */
 248     public function create_cache(cache_definition $definition) {
 249         $loader = null;
 250         if ($definition->has_data_source()) {
 251             $loader = $definition->get_data_source();
 252         }
 253         return new cache_disabled($definition, $this->create_dummy_store($definition), $loader);
 254     }
 255
 256     /**
 257      * Creates a cache object given the parameters for a definition.
 258      *
 259      * @param string $component
 260      * @param string $area
 261      * @param array $identifiers
 262      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 263      * @return cache_application|cache_session|cache_request
 264      */
 265     public function create_cache_from_definition($component, $area, array $identifiers = array(), $unused = null) {
 266         // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php
 267         // definitions as they use load_adhoc().  They are built as a new object on each call.
 268         // We do not need to clone the definition because we know it's new.
 269         $definition = $this->create_definition($component, $area);
 270         $definition->set_identifiers($identifiers);
 271         $cache = $this->create_cache($definition);
 272         return $cache;
 273     }
 274
 275     /**
 276      * Creates an ad-hoc cache from the given param.
 277      *
 278      * @param int $mode
 279      * @param string $component
 280      * @param string $area
 281      * @param array $identifiers
 282      * @param array $options An array of options, available options are:
 283      *   - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_
 284      *   - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars
 285      *   - staticacceleration : If set to true the cache will hold onto all data passing through it.
 286      *   - staticaccelerationsize : Sets the max size of the static acceleration array.
 287      * @return cache_application|cache_session|cache_request
 288      */
 289     public function create_cache_from_params($mode, $component, $area, array $identifiers = array(), array $options = array()) {
 290         // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php
 291         // definitions as they use load_adhoc().  They are built as a new object on each call.
 292         // We do not need to clone the definition because we know it's new.
 293         $definition = cache_definition::load_adhoc($mode, $component, $area, $options);
 294         $definition->set_identifiers($identifiers);
 295         $cache = $this->create_cache($definition);
 296         return $cache;
 297     }
 298
 299     /**
 300      * Creates a store instance given its name and configuration.
 301      *
 302      * @param string $name Unused.
 303      * @param array $details Unused.
 304      * @param cache_definition $definition
 305      * @return boolean|cache_store
 306      */
 307     public function create_store_from_config($name, array $details, cache_definition $definition) {
 308         return $this->create_dummy_store($definition);
 309     }
 310
 311     /**
 312      * Creates a cache config instance with the ability to write if required.
 313      *
 314      * @param bool $writer Unused.
 315      * @return cache_config_disabled|cache_config_writer
 316      */
 317     public function create_config_instance($writer = false) {
 318         // We are always going to use the cache_config_disabled class for all regular request.
 319         // However if the code has requested the writer then likely something is changing and
 320         // we're going to need to interact with the config.php file.
 321         // In this case we will still use the cache_config_writer.
 322         $class = 'cache_config_disabled';
 323         if ($writer) {
 324             // If the writer was requested then something is changing.
 325             $class = 'cache_config_writer';
 326         }
 327         if (!array_key_exists($class, $this->configs)) {
 328             self::set_state(self::STATE_INITIALISING);
 329             if ($class === 'cache_config_disabled') {
 330                 $configuration = $class::create_default_configuration();
 331                 $this->configs[$class] = new $class;
 332             } else {
 333                 $configuration = false;
 334                 // If we need a writer, we should get the classname from the generic factory.
 335                 // This is so alternative classes can be used if a different writer is required.
 336                 $this->configs[$class] = parent::get_disabled_writer();
 337             }
 338             $this->configs[$class]->load($configuration);
 339         }
 340         self::set_state(self::STATE_READY);
 341
 342         // Return the instance.
 343         return $this->configs[$class];
 344     }
 345
 346     /**
 347      * Returns true if the cache API has been disabled.
 348      *
 349      * @return bool
 350      */
 351     public function is_disabled() {
 352         return true;
 353     }
 354 }
 355
 356 /**
 357  * The cache config class used when the Cache has been disabled.
 358  *
 359  * @copyright  2012 Sam Hemelryk
 360  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 361  */
 362 class cache_config_disabled extends cache_config_writer {
 363
 364     /**
 365      * Returns an instance of the configuration writer.
 366      *
 367      * @return cache_config_disabled
 368      */
 369     public static function instance() {
 370         $factory = cache_factory::instance();
 371         return $factory->create_config_instance(true);
 372     }
 373
 374     /**
 375      * Saves the current configuration.
 376      */
 377     protected function config_save() {
 378         // Nothing to do here.
 379     }
 380
 381     /**
 382      * Generates a configuration array suitable to be written to the config file.
 383      *
 384      * @return array
 385      */
 386     protected function generate_configuration_array() {
 387         $configuration = array();
 388         $configuration['stores'] = $this->configstores;
 389         $configuration['modemappings'] = $this->configmodemappings;
 390         $configuration['definitions'] = $this->configdefinitions;
 391         $configuration['definitionmappings'] = $this->configdefinitionmappings;
 392         $configuration['locks'] = $this->configlocks;
 393         return $configuration;
 394     }
 395
 396     /**
 397      * Adds a plugin instance.
 398      *
 399      * @param string $name Unused.
 400      * @param string $plugin Unused.
 401      * @param array $configuration Unused.
 402      * @return bool
 403      * @throws cache_exception
 404      */
 405     public function add_store_instance($name, $plugin, array $configuration = array()) {
 406         return false;
 407     }
 408
 409     /**
 410      * Sets the mode mappings.
 411      *
 412      * @param array $modemappings Unused.
 413      * @return bool
 414      * @throws cache_exception
 415      */
 416     public function set_mode_mappings(array $modemappings) {
 417         return false;
 418     }
 419
 420     /**
 421      * Edits a give plugin instance.
 422      *
 423      * @param string $name Unused.
 424      * @param string $plugin Unused.
 425      * @param array $configuration Unused.
 426      * @return bool
 427      * @throws cache_exception
 428      */
 429     public function edit_store_instance($name, $plugin, $configuration) {
 430         return false;
 431     }
 432
 433     /**
 434      * Deletes a store instance.
 435      *
 436      * @param string $name Unused.
 437      * @return bool
 438      * @throws cache_exception
 439      */
 440     public function delete_store_instance($name) {
 441         return false;
 442     }
 443
 444     /**
 445      * Creates the default configuration and saves it.
 446      *
 447      * @param bool $forcesave Ignored because we are disabled!
 448      * @return array
 449      */
 450     public static function create_default_configuration($forcesave = false) {
 451         global $CFG;
 452
 453         // HACK ALERT.
 454         // We probably need to come up with a better way to create the default stores, or at least ensure 100% that the
 455         // default store plugins are protected from deletion.
 456         require_once($CFG->dirroot.'/cache/stores/file/lib.php');
 457         require_once($CFG->dirroot.'/cache/stores/session/lib.php');
 458         require_once($CFG->dirroot.'/cache/stores/static/lib.php');
 459
 460         $writer = new self;
 461         $writer->configstores = array(
 462             'default_application' => array(
 463                 'name' => 'default_application',
 464                 'plugin' => 'file',
 465                 'configuration' => array(),
 466                 'features' => cachestore_file::get_supported_features(),
 467                 'modes' => cache_store::MODE_APPLICATION,
 468                 'default' => true,
 469             ),
 470             'default_session' => array(
 471                 'name' => 'default_session',
 472                 'plugin' => 'session',
 473                 'configuration' => array(),
 474                 'features' => cachestore_session::get_supported_features(),
 475                 'modes' => cache_store::MODE_SESSION,
 476                 'default' => true,
 477             ),
 478             'default_request' => array(
 479                 'name' => 'default_request',
 480                 'plugin' => 'static',
 481                 'configuration' => array(),
 482                 'features' => cachestore_static::get_supported_features(),
 483                 'modes' => cache_store::MODE_REQUEST,
 484                 'default' => true,
 485             )
 486         );
 487         $writer->configdefinitions = array();
 488         $writer->configmodemappings = array(
 489             array(
 490                 'mode' => cache_store::MODE_APPLICATION,
 491                 'store' => 'default_application',
 492                 'sort' => -1
 493             ),
 494             array(
 495                 'mode' => cache_store::MODE_SESSION,
 496                 'store' => 'default_session',
 497                 'sort' => -1
 498             ),
 499             array(
 500                 'mode' => cache_store::MODE_REQUEST,
 501                 'store' => 'default_request',
 502                 'sort' => -1
 503             )
 504         );
 505         $writer->configlocks = array(
 506             'default_file_lock' => array(
 507                 'name' => 'cachelock_file_default',
 508                 'type' => 'cachelock_file',
 509                 'dir' => 'filelocks',
 510                 'default' => true
 511             )
 512         );
 513
 514         return $writer->generate_configuration_array();
 515     }
 516
 517     /**
 518      * Updates the definition in the configuration from those found in the cache files.
 519      *
 520      * @param bool $coreonly Unused.
 521      */
 522     public static function update_definitions($coreonly = false) {
 523         // Nothing to do here.
 524     }
 525
 526     /**
 527      * Locates all of the definition files.
 528      *
 529      * @param bool $coreonly Unused.
 530      * @return array
 531      */
 532     protected static function locate_definitions($coreonly = false) {
 533         return array();
 534     }
 535
 536     /**
 537      * Sets the mappings for a given definition.
 538      *
 539      * @param string $definition Unused.
 540      * @param array $mappings Unused.
 541      * @throws coding_exception
 542      */
 543     public function set_definition_mappings($definition, $mappings) {
 544         // Nothing to do here.
 545     }
 546 }