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         // Nothing to do here.
  53     }
  54
  55     /**
  56      * Gets a key from the cache.
  57      *
  58      * @param int|string $key
  59      * @param int $strictness Unused.
  60      * @return bool
  61      */
  62     public function get($key, $strictness = IGNORE_MISSING) {
  63         return false;
  64     }
  65
  66     /**
  67      * Gets many keys at once from the cache.
  68      *
  69      * @param array $keys
  70      * @param int $strictness Unused.
  71      * @return array
  72      */
  73     public function get_many(array $keys, $strictness = IGNORE_MISSING) {
  74         $return = array();
  75         foreach ($keys as $key) {
  76             $return[$key] = false;
  77         }
  78         return $return;
  79     }
  80
  81     /**
  82      * Sets a key value pair in the cache.
  83      *
  84      * @param int|string $key Unused.
  85      * @param mixed $data Unused.
  86      * @return bool
  87      */
  88     public function set($key, $data) {
  89         return false;
  90     }
  91
  92     /**
  93      * Sets many key value pairs in the cache at once.
  94      *
  95      * @param array $keyvaluearray Unused.
  96      * @return int
  97      */
  98     public function set_many(array $keyvaluearray) {
  99         return 0;
 100     }
 101
 102     /**
 103      * Deletes an item from the cache.
 104      *
 105      * @param int|string $key Unused.
 106      * @param bool $recurse Unused.
 107      * @return bool
 108      */
 109     public function delete($key, $recurse = true) {
 110         return false;
 111     }
 112
 113     /**
 114      * Deletes many items at once from the cache.
 115      *
 116      * @param array $keys Unused.
 117      * @param bool $recurse Unused.
 118      * @return int
 119      */
 120     public function delete_many(array $keys, $recurse = true) {
 121         return 0;
 122     }
 123
 124     /**
 125      * Checks if the cache has the requested key.
 126      *
 127      * @param int|string $key Unused.
 128      * @return bool
 129      */
 130     public function has($key) {
 131         return false;
 132     }
 133
 134     /**
 135      * Checks if the cache has all of the requested keys.
 136      * @param array $keys Unused.
 137      * @return bool
 138      */
 139     public function has_all(array $keys) {
 140         return false;
 141     }
 142
 143     /**
 144      * Checks if the cache has any of the requested keys.
 145      *
 146      * @param array $keys Unused.
 147      * @return bool
 148      */
 149     public function has_any(array $keys) {
 150         return false;
 151     }
 152
 153     /**
 154      * Purges all items from the cache.
 155      *
 156      * @return bool
 157      */
 158     public function purge() {
 159         return true;
 160     }
 161 }
 162
 163 /**
 164  * The cache factory class used when the Cache has been disabled.
 165  *
 166  * @copyright  2012 Sam Hemelryk
 167  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 168  */
 169 class cache_factory_disabled extends cache_factory {
 170
 171     /**
 172      * Returns an instance of the cache_factor method.
 173      *
 174      * @param bool $forcereload Unused.
 175      * @return cache_factory
 176      * @throws coding_exception
 177      */
 178     public static function instance($forcereload = false) {
 179         throw new coding_exception('You must not call to this cache factory within your code.');
 180     }
 181
 182     /**
 183      * Creates a definition instance or returns the existing one if it has already been created.
 184      *
 185      * @param string $component
 186      * @param string $area
 187      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 188      * @return cache_definition
 189      */
 190     public function create_definition($component, $area, $unused = null) {
 191         return cache_definition::load_adhoc(cache_store::MODE_REQUEST, $component, $area);
 192     }
 193
 194     /**
 195      * Common public method to create a cache instance given a definition.
 196      *
 197      * @param cache_definition $definition
 198      * @return cache_application|cache_session|cache_store
 199      * @throws coding_exception
 200      */
 201     public function create_cache(cache_definition $definition) {
 202         return new cache_disabled($definition, $this->create_dummy_store($definition));
 203     }
 204
 205     /**
 206      * Creates a cache object given the parameters for a definition.
 207      *
 208      * @param string $component
 209      * @param string $area
 210      * @param array $identifiers
 211      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 212      * @return cache_application|cache_session|cache_request
 213      */
 214     public function create_cache_from_definition($component, $area, array $identifiers = array(), $unused = null) {
 215         $definition = $this->create_definition($component, $area);
 216         $cache = $this->create_cache($definition, $identifiers);
 217         return $cache;
 218     }
 219
 220     /**
 221      * Creates an ad-hoc cache from the given param.
 222      *
 223      * @param int $mode
 224      * @param string $component
 225      * @param string $area
 226      * @param array $identifiers
 227      * @param array $options An array of options, available options are:
 228      *   - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_
 229      *   - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars
 230      *   - staticacceleration : If set to true the cache will hold onto all data passing through it.
 231      *   - staticaccelerationsize : Sets the max size of the static acceleration array.
 232      * @return cache_application|cache_session|cache_request
 233      */
 234     public function create_cache_from_params($mode, $component, $area, array $identifiers = array(), array $options = array()) {
 235         $definition = cache_definition::load_adhoc($mode, $component, $area);
 236         $cache = $this->create_cache($definition, $identifiers);
 237         return $cache;
 238     }
 239
 240     /**
 241      * Creates a store instance given its name and configuration.
 242      *
 243      * @param string $name Unused.
 244      * @param array $details Unused.
 245      * @param cache_definition $definition
 246      * @return boolean|cache_store
 247      */
 248     public function create_store_from_config($name, array $details, cache_definition $definition) {
 249         return $this->create_dummy_store($definition);
 250     }
 251
 252     /**
 253      * Creates a cache config instance with the ability to write if required.
 254      *
 255      * @param bool $writer Unused.
 256      * @return cache_config_disabled|cache_config_writer
 257      */
 258     public function create_config_instance($writer = false) {
 259         // We are always going to use the cache_config_disabled class for all regular request.
 260         // However if the code has requested the writer then likely something is changing and
 261         // we're going to need to interact with the config.php file.
 262         // In this case we will still use the cache_config_writer.
 263         $class = 'cache_config_disabled';
 264         if ($writer) {
 265             // If the writer was requested then something is changing.
 266             $class = 'cache_config_writer';
 267         }
 268         if (!array_key_exists($class, $this->configs)) {
 269             self::set_state(self::STATE_INITIALISING);
 270             if ($class === 'cache_config_disabled') {
 271                 $configuration = $class::create_default_configuration();
 272             } else {
 273                 $configuration = false;
 274                 if (!cache_config::config_file_exists()) {
 275                     cache_config_writer::create_default_configuration(true);
 276                 }
 277             }
 278             $this->configs[$class] = new $class;
 279             $this->configs[$class]->load($configuration);
 280         }
 281         self::set_state(self::STATE_READY);
 282
 283         // Return the instance.
 284         return $this->configs[$class];
 285     }
 286 }
 287
 288 /**
 289  * The cache config class used when the Cache has been disabled.
 290  *
 291  * @copyright  2012 Sam Hemelryk
 292  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 293  */
 294 class cache_config_disabled extends cache_config_writer {
 295
 296     /**
 297      * Returns an instance of the configuration writer.
 298      *
 299      * @return cache_config_disabled
 300      */
 301     public static function instance() {
 302         $factory = cache_factory::instance();
 303         return $factory->create_config_instance(true);
 304     }
 305
 306     /**
 307      * Saves the current configuration.
 308      */
 309     protected function config_save() {
 310         // Nothing to do here.
 311     }
 312
 313     /**
 314      * Generates a configuration array suitable to be written to the config file.
 315      *
 316      * @return array
 317      */
 318     protected function generate_configuration_array() {
 319         $configuration = array();
 320         $configuration['stores'] = $this->configstores;
 321         $configuration['modemappings'] = $this->configmodemappings;
 322         $configuration['definitions'] = $this->configdefinitions;
 323         $configuration['definitionmappings'] = $this->configdefinitionmappings;
 324         $configuration['locks'] = $this->configlocks;
 325         return $configuration;
 326     }
 327
 328     /**
 329      * Adds a plugin instance.
 330      *
 331      * @param string $name Unused.
 332      * @param string $plugin Unused.
 333      * @param array $configuration Unused.
 334      * @return bool
 335      * @throws cache_exception
 336      */
 337     public function add_store_instance($name, $plugin, array $configuration = array()) {
 338         return false;
 339     }
 340
 341     /**
 342      * Sets the mode mappings.
 343      *
 344      * @param array $modemappings Unused.
 345      * @return bool
 346      * @throws cache_exception
 347      */
 348     public function set_mode_mappings(array $modemappings) {
 349         return false;
 350     }
 351
 352     /**
 353      * Edits a give plugin instance.
 354      *
 355      * @param string $name Unused.
 356      * @param string $plugin Unused.
 357      * @param array $configuration Unused.
 358      * @return bool
 359      * @throws cache_exception
 360      */
 361     public function edit_store_instance($name, $plugin, $configuration) {
 362         return false;
 363     }
 364
 365     /**
 366      * Deletes a store instance.
 367      *
 368      * @param string $name Unused.
 369      * @return bool
 370      * @throws cache_exception
 371      */
 372     public function delete_store_instance($name) {
 373         return false;
 374     }
 375
 376     /**
 377      * Creates the default configuration and saves it.
 378      *
 379      * @param bool $forcesave Ignored because we are disabled!
 380      * @return array
 381      */
 382     public static function create_default_configuration($forcesave = false) {
 383         global $CFG;
 384
 385         // HACK ALERT.
 386         // We probably need to come up with a better way to create the default stores, or at least ensure 100% that the
 387         // default store plugins are protected from deletion.
 388         require_once($CFG->dirroot.'/cache/stores/file/lib.php');
 389         require_once($CFG->dirroot.'/cache/stores/session/lib.php');
 390         require_once($CFG->dirroot.'/cache/stores/static/lib.php');
 391
 392         $writer = new self;
 393         $writer->configstores = array(
 394             'default_application' => array(
 395                 'name' => 'default_application',
 396                 'plugin' => 'file',
 397                 'configuration' => array(),
 398                 'features' => cachestore_file::get_supported_features(),
 399                 'modes' => cache_store::MODE_APPLICATION,
 400                 'default' => true,
 401             ),
 402             'default_session' => array(
 403                 'name' => 'default_session',
 404                 'plugin' => 'session',
 405                 'configuration' => array(),
 406                 'features' => cachestore_session::get_supported_features(),
 407                 'modes' => cache_store::MODE_SESSION,
 408                 'default' => true,
 409             ),
 410             'default_request' => array(
 411                 'name' => 'default_request',
 412                 'plugin' => 'static',
 413                 'configuration' => array(),
 414                 'features' => cachestore_static::get_supported_features(),
 415                 'modes' => cache_store::MODE_REQUEST,
 416                 'default' => true,
 417             )
 418         );
 419         $writer->configdefinitions = array();
 420         $writer->configmodemappings = array(
 421             array(
 422                 'mode' => cache_store::MODE_APPLICATION,
 423                 'store' => 'default_application',
 424                 'sort' => -1
 425             ),
 426             array(
 427                 'mode' => cache_store::MODE_SESSION,
 428                 'store' => 'default_session',
 429                 'sort' => -1
 430             ),
 431             array(
 432                 'mode' => cache_store::MODE_REQUEST,
 433                 'store' => 'default_request',
 434                 'sort' => -1
 435             )
 436         );
 437         $writer->configlocks = array(
 438             'default_file_lock' => array(
 439                 'name' => 'cachelock_file_default',
 440                 'type' => 'cachelock_file',
 441                 'dir' => 'filelocks',
 442                 'default' => true
 443             )
 444         );
 445
 446         return $writer->generate_configuration_array();
 447     }
 448
 449     /**
 450      * Updates the definition in the configuration from those found in the cache files.
 451      *
 452      * @param bool $coreonly Unused.
 453      */
 454     public static function update_definitions($coreonly = false) {
 455         // Nothing to do here.
 456     }
 457
 458     /**
 459      * Locates all of the definition files.
 460      *
 461      * @param bool $coreonly Unused.
 462      * @return array
 463      */
 464     protected static function locate_definitions($coreonly = false) {
 465         return array();
 466     }
 467
 468     /**
 469      * Sets the mappings for a given definition.
 470      *
 471      * @param string $definition Unused.
 472      * @param array $mappings Unused.
 473      * @throws coding_exception
 474      */
 475     public function set_definition_mappings($definition, $mappings) {
 476         // Nothing to do here.
 477     }
 478 }