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      * @param bool $tryloadifpossible Unused.
 129      * @return bool
 130      */
 131     public function has($key, $tryloadifpossible = false) {
 132         return false;
 133     }
 134
 135     /**
 136      * Checks if the cache has all of the requested keys.
 137      * @param array $keys Unused.
 138      * @return bool
 139      */
 140     public function has_all(array $keys) {
 141         return false;
 142     }
 143
 144     /**
 145      * Checks if the cache has any of the requested keys.
 146      *
 147      * @param array $keys Unused.
 148      * @return bool
 149      */
 150     public function has_any(array $keys) {
 151         return false;
 152     }
 153
 154     /**
 155      * Purges all items from the cache.
 156      *
 157      * @return bool
 158      */
 159     public function purge() {
 160         return true;
 161     }
 162 }
 163
 164 /**
 165  * The cache factory class used when the Cache has been disabled.
 166  *
 167  * @copyright  2012 Sam Hemelryk
 168  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 169  */
 170 class cache_factory_disabled extends cache_factory {
 171
 172     /**
 173      * Returns an instance of the cache_factor method.
 174      *
 175      * @param bool $forcereload Unused.
 176      * @return cache_factory
 177      * @throws coding_exception
 178      */
 179     public static function instance($forcereload = false) {
 180         throw new coding_exception('You must not call to this cache factory within your code.');
 181     }
 182
 183     /**
 184      * Creates a definition instance or returns the existing one if it has already been created.
 185      *
 186      * @param string $component
 187      * @param string $area
 188      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 189      * @return cache_definition
 190      */
 191     public function create_definition($component, $area, $unused = null) {
 192         return cache_definition::load_adhoc(cache_store::MODE_REQUEST, $component, $area);
 193     }
 194
 195     /**
 196      * Common public method to create a cache instance given a definition.
 197      *
 198      * @param cache_definition $definition
 199      * @return cache_application|cache_session|cache_store
 200      * @throws coding_exception
 201      */
 202     public function create_cache(cache_definition $definition) {
 203         return new cache_disabled($definition, $this->create_dummy_store($definition));
 204     }
 205
 206     /**
 207      * Creates a cache object given the parameters for a definition.
 208      *
 209      * @param string $component
 210      * @param string $area
 211      * @param array $identifiers
 212      * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.
 213      * @return cache_application|cache_session|cache_request
 214      */
 215     public function create_cache_from_definition($component, $area, array $identifiers = array(), $unused = null) {
 216         // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php
 217         // definitions as they use load_adhoc().  They are built as a new object on each call.
 218         // We do not need to clone the definition because we know it's new.
 219         $definition = $this->create_definition($component, $area);
 220         $definition->set_identifiers($identifiers);
 221         $cache = $this->create_cache($definition);
 222         return $cache;
 223     }
 224
 225     /**
 226      * Creates an ad-hoc cache from the given param.
 227      *
 228      * @param int $mode
 229      * @param string $component
 230      * @param string $area
 231      * @param array $identifiers
 232      * @param array $options An array of options, available options are:
 233      *   - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_
 234      *   - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars
 235      *   - staticacceleration : If set to true the cache will hold onto all data passing through it.
 236      *   - staticaccelerationsize : Sets the max size of the static acceleration array.
 237      * @return cache_application|cache_session|cache_request
 238      */
 239     public function create_cache_from_params($mode, $component, $area, array $identifiers = array(), array $options = array()) {
 240         // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php
 241         // definitions as they use load_adhoc().  They are built as a new object on each call.
 242         // We do not need to clone the definition because we know it's new.
 243         $definition = cache_definition::load_adhoc($mode, $component, $area, $options);
 244         $definition->set_identifiers($identifiers);
 245         $cache = $this->create_cache($definition);
 246         return $cache;
 247     }
 248
 249     /**
 250      * Creates a store instance given its name and configuration.
 251      *
 252      * @param string $name Unused.
 253      * @param array $details Unused.
 254      * @param cache_definition $definition
 255      * @return boolean|cache_store
 256      */
 257     public function create_store_from_config($name, array $details, cache_definition $definition) {
 258         return $this->create_dummy_store($definition);
 259     }
 260
 261     /**
 262      * Creates a cache config instance with the ability to write if required.
 263      *
 264      * @param bool $writer Unused.
 265      * @return cache_config_disabled|cache_config_writer
 266      */
 267     public function create_config_instance($writer = false) {
 268         // We are always going to use the cache_config_disabled class for all regular request.
 269         // However if the code has requested the writer then likely something is changing and
 270         // we're going to need to interact with the config.php file.
 271         // In this case we will still use the cache_config_writer.
 272         $class = 'cache_config_disabled';
 273         if ($writer) {
 274             // If the writer was requested then something is changing.
 275             $class = 'cache_config_writer';
 276         }
 277         if (!array_key_exists($class, $this->configs)) {
 278             self::set_state(self::STATE_INITIALISING);
 279             if ($class === 'cache_config_disabled') {
 280                 $configuration = $class::create_default_configuration();
 281             } else {
 282                 $configuration = false;
 283                 if (!cache_config::config_file_exists()) {
 284                     cache_config_writer::create_default_configuration(true);
 285                 }
 286             }
 287             $this->configs[$class] = new $class;
 288             $this->configs[$class]->load($configuration);
 289         }
 290         self::set_state(self::STATE_READY);
 291
 292         // Return the instance.
 293         return $this->configs[$class];
 294     }
 295 }
 296
 297 /**
 298  * The cache config class used when the Cache has been disabled.
 299  *
 300  * @copyright  2012 Sam Hemelryk
 301  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 302  */
 303 class cache_config_disabled extends cache_config_writer {
 304
 305     /**
 306      * Returns an instance of the configuration writer.
 307      *
 308      * @return cache_config_disabled
 309      */
 310     public static function instance() {
 311         $factory = cache_factory::instance();
 312         return $factory->create_config_instance(true);
 313     }
 314
 315     /**
 316      * Saves the current configuration.
 317      */
 318     protected function config_save() {
 319         // Nothing to do here.
 320     }
 321
 322     /**
 323      * Generates a configuration array suitable to be written to the config file.
 324      *
 325      * @return array
 326      */
 327     protected function generate_configuration_array() {
 328         $configuration = array();
 329         $configuration['stores'] = $this->configstores;
 330         $configuration['modemappings'] = $this->configmodemappings;
 331         $configuration['definitions'] = $this->configdefinitions;
 332         $configuration['definitionmappings'] = $this->configdefinitionmappings;
 333         $configuration['locks'] = $this->configlocks;
 334         return $configuration;
 335     }
 336
 337     /**
 338      * Adds a plugin instance.
 339      *
 340      * @param string $name Unused.
 341      * @param string $plugin Unused.
 342      * @param array $configuration Unused.
 343      * @return bool
 344      * @throws cache_exception
 345      */
 346     public function add_store_instance($name, $plugin, array $configuration = array()) {
 347         return false;
 348     }
 349
 350     /**
 351      * Sets the mode mappings.
 352      *
 353      * @param array $modemappings Unused.
 354      * @return bool
 355      * @throws cache_exception
 356      */
 357     public function set_mode_mappings(array $modemappings) {
 358         return false;
 359     }
 360
 361     /**
 362      * Edits a give plugin instance.
 363      *
 364      * @param string $name Unused.
 365      * @param string $plugin Unused.
 366      * @param array $configuration Unused.
 367      * @return bool
 368      * @throws cache_exception
 369      */
 370     public function edit_store_instance($name, $plugin, $configuration) {
 371         return false;
 372     }
 373
 374     /**
 375      * Deletes a store instance.
 376      *
 377      * @param string $name Unused.
 378      * @return bool
 379      * @throws cache_exception
 380      */
 381     public function delete_store_instance($name) {
 382         return false;
 383     }
 384
 385     /**
 386      * Creates the default configuration and saves it.
 387      *
 388      * @param bool $forcesave Ignored because we are disabled!
 389      * @return array
 390      */
 391     public static function create_default_configuration($forcesave = false) {
 392         global $CFG;
 393
 394         // HACK ALERT.
 395         // We probably need to come up with a better way to create the default stores, or at least ensure 100% that the
 396         // default store plugins are protected from deletion.
 397         require_once($CFG->dirroot.'/cache/stores/file/lib.php');
 398         require_once($CFG->dirroot.'/cache/stores/session/lib.php');
 399         require_once($CFG->dirroot.'/cache/stores/static/lib.php');
 400
 401         $writer = new self;
 402         $writer->configstores = array(
 403             'default_application' => array(
 404                 'name' => 'default_application',
 405                 'plugin' => 'file',
 406                 'configuration' => array(),
 407                 'features' => cachestore_file::get_supported_features(),
 408                 'modes' => cache_store::MODE_APPLICATION,
 409                 'default' => true,
 410             ),
 411             'default_session' => array(
 412                 'name' => 'default_session',
 413                 'plugin' => 'session',
 414                 'configuration' => array(),
 415                 'features' => cachestore_session::get_supported_features(),
 416                 'modes' => cache_store::MODE_SESSION,
 417                 'default' => true,
 418             ),
 419             'default_request' => array(
 420                 'name' => 'default_request',
 421                 'plugin' => 'static',
 422                 'configuration' => array(),
 423                 'features' => cachestore_static::get_supported_features(),
 424                 'modes' => cache_store::MODE_REQUEST,
 425                 'default' => true,
 426             )
 427         );
 428         $writer->configdefinitions = array();
 429         $writer->configmodemappings = array(
 430             array(
 431                 'mode' => cache_store::MODE_APPLICATION,
 432                 'store' => 'default_application',
 433                 'sort' => -1
 434             ),
 435             array(
 436                 'mode' => cache_store::MODE_SESSION,
 437                 'store' => 'default_session',
 438                 'sort' => -1
 439             ),
 440             array(
 441                 'mode' => cache_store::MODE_REQUEST,
 442                 'store' => 'default_request',
 443                 'sort' => -1
 444             )
 445         );
 446         $writer->configlocks = array(
 447             'default_file_lock' => array(
 448                 'name' => 'cachelock_file_default',
 449                 'type' => 'cachelock_file',
 450                 'dir' => 'filelocks',
 451                 'default' => true
 452             )
 453         );
 454
 455         return $writer->generate_configuration_array();
 456     }
 457
 458     /**
 459      * Updates the definition in the configuration from those found in the cache files.
 460      *
 461      * @param bool $coreonly Unused.
 462      */
 463     public static function update_definitions($coreonly = false) {
 464         // Nothing to do here.
 465     }
 466
 467     /**
 468      * Locates all of the definition files.
 469      *
 470      * @param bool $coreonly Unused.
 471      * @return array
 472      */
 473     protected static function locate_definitions($coreonly = false) {
 474         return array();
 475     }
 476
 477     /**
 478      * Sets the mappings for a given definition.
 479      *
 480      * @param string $definition Unused.
 481      * @param array $mappings Unused.
 482      * @throws coding_exception
 483      */
 484     public function set_definition_mappings($definition, $mappings) {
 485         // Nothing to do here.
 486     }
 487 }