Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * This file contains classes that are used by the Cache API only when it is disabled.

 *

 * These classes are derivatives of other significant classes used by the Cache API customised specifically

 * to only do what is absolutely necessary when initialising and using the Cache API when its been disabled.

 *

 * @package    core

 * @category   cache

 * @copyright  2012 Sam Hemelryk

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

/**

 * Required as it is needed for cache_config_disabled which extends cache_config_writer.

 */

require_once($CFG->dirroot.'/cache/locallib.php');

/**

 * The cache loader class used when the Cache has been disabled.

 *

 * @copyright  2012 Sam Hemelryk

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class cache_disabled extends cache implements cache_loader_with_locking {

    /**

     * Constructs the cache.

     *

     * @param cache_definition $definition

     * @param cache_store $store

     * @param null $loader Unused.

     */

    public function __construct(cache_definition $definition, cache_store $store, $loader = null) {

        if ($loader instanceof cache_data_source) {

            // Set the data source to allow data sources to work when caching is entirely disabled.

            $this->set_data_source($loader);

        }

        // No other features are handled.

    }

    /**

     * Gets a key from the cache.

     *

     * @param int|string $key

     * @param int $requiredversion Minimum required version of the data or cache::VERSION_NONE

     * @param int $strictness Unused.

     * @param mixed &$actualversion If specified, will be set to the actual version number retrieved

     * @return bool

     */

    protected function get_implementation($key, int $requiredversion, int $strictness, &$actualversion = null) {

        $datasource = $this->get_datasource();

        if ($datasource !== false) {

            if ($requiredversion === cache::VERSION_NONE) {

                return $datasource->load_for_cache($key);

            } else {

                if (!$datasource instanceof cache_data_source_versionable) {

                    throw new \coding_exception('Data source is not versionable');

                }

                $result = $datasource->load_for_cache_versioned($key, $requiredversion, $actualversion);

                if ($result && $actualversion < $requiredversion) {

                    throw new \coding_exception('Data source returned outdated version');

                }

                return $result;

            }

        }

        return false;

    }

    /**

     * Gets many keys at once from the cache.

     *

     * @param array $keys

     * @param int $strictness Unused.

     * @return array

     */

    public function get_many(array $keys, $strictness = IGNORE_MISSING) {

        if ($this->get_datasource() !== false) {

            return $this->get_datasource()->load_many_for_cache($keys);

        }

        return array_combine($keys, array_fill(0, count($keys), false));

    }

    /**

     * Sets a key value pair in the cache.

     *

     * @param int|string $key Unused.

     * @param int $version Unused.

     * @param mixed $data Unused.

     * @param bool $setparents Unused.

     * @return bool

     */

    protected function set_implementation($key, int $version, $data, bool $setparents = true): bool {

        return false;

    }

    /**

     * Sets many key value pairs in the cache at once.

     *

     * @param array $keyvaluearray Unused.

     * @return int

     */

    public function set_many(array $keyvaluearray) {

        return 0;

    }

    /**

     * Deletes an item from the cache.

     *

     * @param int|string $key Unused.

     * @param bool $recurse Unused.

     * @return bool

     */

    public function delete($key, $recurse = true) {

        return false;

    }

    /**

     * Deletes many items at once from the cache.

     *

     * @param array $keys Unused.

     * @param bool $recurse Unused.

     * @return int

     */

    public function delete_many(array $keys, $recurse = true) {

        return 0;

    }

    /**

     * Checks if the cache has the requested key.

     *

     * @param int|string $key Unused.

     * @param bool $tryloadifpossible Unused.

     * @return bool

     */

    public function has($key, $tryloadifpossible = false) {

        $result = $this->get($key);

        return $result !== false;

    }

    /**

     * Checks if the cache has all of the requested keys.

     * @param array $keys Unused.

     * @return bool

     */

    public function has_all(array $keys) {

        if (!$this->get_datasource()) {

            return false;

        }

        foreach ($keys as $key) {

            if (!$this->has($key)) {

                return false;

            }

        }

        return true;

    }

    /**

     * Checks if the cache has any of the requested keys.

     *

     * @param array $keys Unused.

     * @return bool

     */

    public function has_any(array $keys) {

        foreach ($keys as $key) {

            if ($this->has($key)) {

                return true;

            }

        }

        return false;

    }

    /**

     * Purges all items from the cache.

     *

     * @return bool

     */

    public function purge() {

        return true;

    }

    /**

     * Pretend that we got a lock to avoid errors.

     *

     * @param int|string $key

     * @return bool

     */

    public function acquire_lock($key): bool {

        return true;

    }

    /**

     * Pretend that we released a lock to avoid errors.

     *

     * @param int|string $key

     * @return bool

     */

    public function release_lock($key): bool {

        return true;

    }

    /**

     * Pretend that we have a lock to avoid errors.

     *

     * @param int|string $key

     * @return bool

     */

    public function check_lock_state($key): bool {

        return true;

    }

}

/**

 * The cache factory class used when the Cache has been disabled.

 *

 * @copyright  2012 Sam Hemelryk

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class cache_factory_disabled extends cache_factory {

    /** @var array Array of temporary caches in use. */

    protected static $tempcaches = [];

    /**

     * Returns an instance of the cache_factor method.

     *

     * @param bool $forcereload Unused.

     * @return cache_factory

     * @throws coding_exception

     */

    public static function instance($forcereload = false) {

        throw new coding_exception('You must not call to this cache factory within your code.');

    }

    /**

     * Creates a definition instance or returns the existing one if it has already been created.

     *

     * @param string $component

     * @param string $area

     * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.

     * @return cache_definition

     */

    public function create_definition($component, $area, $unused = null) {

        $definition = parent::create_definition($component, $area);

        if ($definition->has_data_source()) {

            return $definition;

        }

        return cache_definition::load_adhoc(cache_store::MODE_REQUEST, $component, $area);

    }

    /**

     * Common public method to create a cache instance given a definition.

     *

     * @param cache_definition $definition

     * @return cache_application|cache_session|cache_store

     * @throws coding_exception

     */

    public function create_cache(cache_definition $definition) {

        $loader = null;

        if ($definition->has_data_source()) {

            $loader = $definition->get_data_source();

        }

        return new cache_disabled($definition, $this->create_dummy_store($definition), $loader);

    }

    /**

     * Creates a cache object given the parameters for a definition.

     *

     * @param string $component

     * @param string $area

     * @param array $identifiers

     * @param string $unused Used to be datasourceaggregate but that was removed and this is now unused.

     * @return cache_application|cache_session|cache_request

     */

    public function create_cache_from_definition($component, $area, array $identifiers = array(), $unused = null) {

        // Temporary in-memory caches are sometimes allowed when caching is disabled.

        if (\core_cache\allow_temporary_caches::is_allowed() && !$identifiers) {

            $key = $component . '/' . $area;

            if (array_key_exists($key, self::$tempcaches)) {

                $cache = self::$tempcaches[$key];

            } else {

                $definition = $this->create_definition($component, $area);

                // The cachestore_static class returns true to all three 'SUPPORTS_' checks so it

                // can be used with all definitions.

                $store = new cachestore_static('TEMP:' . $component . '/' . $area);

                $store->initialise($definition);

                // We need to use a cache loader wrapper rather than directly returning the store,

                // or it wouldn't have support for versioning. The cache_application class is used

                // (rather than cache_request which might make more sense logically) because it

                // includes support for locking, which might be necessary for some caches.

                $cache = new cache_application($definition, $store);

                self::$tempcaches[$key] = $cache;

            }

            return $cache;

        }

        // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php

        // definitions as they use load_adhoc().  They are built as a new object on each call.

        // We do not need to clone the definition because we know it's new.

        $definition = $this->create_definition($component, $area);

        $definition->set_identifiers($identifiers);

        $cache = $this->create_cache($definition);

        return $cache;

    }

    /**

     * Removes all temporary caches.

     *

     * Don't call this directly - used by {@see \core_cache\allow_temporary_caches}.

     */

    public static function clear_temporary_caches(): void {

        self::$tempcaches = [];

    }

    /**

     * Creates an ad-hoc cache from the given param.

     *

     * @param int $mode

     * @param string $component

     * @param string $area

     * @param array $identifiers

     * @param array $options An array of options, available options are:

     *   - simplekeys : Set to true if the keys you will use are a-zA-Z0-9_

     *   - simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars

     *   - staticacceleration : If set to true the cache will hold onto all data passing through it.

     *   - staticaccelerationsize : Sets the max size of the static acceleration array.

     * @return cache_application|cache_session|cache_request

     */

    public function create_cache_from_params($mode, $component, $area, array $identifiers = array(), array $options = array()) {

        // Regular cache definitions are cached inside create_definition().  This is not the case for disabledlib.php

        // definitions as they use load_adhoc().  They are built as a new object on each call.

        // We do not need to clone the definition because we know it's new.

        $definition = cache_definition::load_adhoc($mode, $component, $area, $options);

        $definition->set_identifiers($identifiers);

        $cache = $this->create_cache($definition);

        return $cache;

    }

    /**

     * Creates a store instance given its name and configuration.

     *

     * @param string $name Unused.

     * @param array $details Unused.

     * @param cache_definition $definition

     * @return boolean|cache_store

     */

    public function create_store_from_config($name, array $details, cache_definition $definition) {

        return $this->create_dummy_store($definition);

    }

    /**

     * Creates a cache config instance with the ability to write if required.

     *

     * @param bool $writer Unused.

     * @return cache_config_disabled|cache_config_writer

     */

    public function create_config_instance($writer = false) {

        // We are always going to use the cache_config_disabled class for all regular request.

        // However if the code has requested the writer then likely something is changing and

        // we're going to need to interact with the config.php file.

        // In this case we will still use the cache_config_writer.

        $class = 'cache_config_disabled';

        if ($writer) {

            // If the writer was requested then something is changing.

            $class = 'cache_config_writer';

        }

        if (!array_key_exists($class, $this->configs)) {

            self::set_state(self::STATE_INITIALISING);

            if ($class === 'cache_config_disabled') {

                $configuration = $class::create_default_configuration();

                $this->configs[$class] = new $class;

            } else {

                $configuration = false;

                // If we need a writer, we should get the classname from the generic factory.

                // This is so alternative classes can be used if a different writer is required.

                $this->configs[$class] = parent::get_disabled_writer();

            }

            $this->configs[$class]->load($configuration);

        }

        self::set_state(self::STATE_READY);

        // Return the instance.

        return $this->configs[$class];

    }

    /**

     * Returns true if the cache API has been disabled.

     *

     * @return bool

     */

    public function is_disabled() {

        return true;

    }

}

/**

 * The cache config class used when the Cache has been disabled.

 *

 * @copyright  2012 Sam Hemelryk

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class cache_config_disabled extends cache_config_writer {

    /**

     * Returns an instance of the configuration writer.

     *

     * @return cache_config_disabled

     */

    public static function instance() {

        $factory = cache_factory::instance();

        return $factory->create_config_instance(true);

    }

    /**

     * Saves the current configuration.

     */

    protected function config_save() {

        // Nothing to do here.

    }

    /**

     * Generates a configuration array suitable to be written to the config file.

     *

     * @return array

     */

    protected function generate_configuration_array() {

        $configuration = array();

        $configuration['stores'] = $this->configstores;

        $configuration['modemappings'] = $this->configmodemappings;

        $configuration['definitions'] = $this->configdefinitions;

        $configuration['definitionmappings'] = $this->configdefinitionmappings;

        $configuration['locks'] = $this->configlocks;

        return $configuration;

    }

    /**

     * Adds a plugin instance.

     *

     * @param string $name Unused.

     * @param string $plugin Unused.

     * @param array $configuration Unused.

     * @return bool

     * @throws cache_exception

     */

    public function add_store_instance($name, $plugin, array $configuration = array()) {

        return false;

    }

    /**

     * Sets the mode mappings.

     *

     * @param array $modemappings Unused.

     * @return bool

     * @throws cache_exception

     */

    public function set_mode_mappings(array $modemappings) {

        return false;

    }

    /**

     * Edits a give plugin instance.

     *

     * @param string $name Unused.

     * @param string $plugin Unused.

     * @param array $configuration Unused.

     * @return bool

     * @throws cache_exception

     */

    public function edit_store_instance($name, $plugin, $configuration) {

        return false;

    }

    /**

     * Deletes a store instance.

     *

     * @param string $name Unused.

     * @return bool

     * @throws cache_exception

     */

    public function delete_store_instance($name) {

        return false;

    }

    /**

     * Creates the default configuration and saves it.

     *

     * @param bool $forcesave Ignored because we are disabled!

     * @return array

     */

    public static function create_default_configuration($forcesave = false) {

        global $CFG;

        // HACK ALERT.

        // We probably need to come up with a better way to create the default stores, or at least ensure 100% that the

        // default store plugins are protected from deletion.

        require_once($CFG->dirroot.'/cache/stores/file/lib.php');

        require_once($CFG->dirroot.'/cache/stores/session/lib.php');

        require_once($CFG->dirroot.'/cache/stores/static/lib.php');

        $writer = new self;

        $writer->configstores = array(

            'default_application' => array(

                'name' => 'default_application',

                'plugin' => 'file',

                'configuration' => array(),

                'features' => cachestore_file::get_supported_features(),

                'modes' => cache_store::MODE_APPLICATION,

                'default' => true,

            ),

            'default_session' => array(

                'name' => 'default_session',

                'plugin' => 'session',

                'configuration' => array(),

                'features' => cachestore_session::get_supported_features(),

                'modes' => cache_store::MODE_SESSION,

                'default' => true,

            ),

            'default_request' => array(

                'name' => 'default_request',

                'plugin' => 'static',

                'configuration' => array(),

                'features' => cachestore_static::get_supported_features(),

                'modes' => cache_store::MODE_REQUEST,

                'default' => true,

            )

        );

        $writer->configdefinitions = array();

        $writer->configmodemappings = array(

            array(

                'mode' => cache_store::MODE_APPLICATION,

                'store' => 'default_application',

                'sort' => -1

            ),

            array(

                'mode' => cache_store::MODE_SESSION,

                'store' => 'default_session',

                'sort' => -1

            ),

            array(

                'mode' => cache_store::MODE_REQUEST,

                'store' => 'default_request',

                'sort' => -1

            )

        );

        $writer->configlocks = array(

            'default_file_lock' => array(

                'name' => 'cachelock_file_default',

                'type' => 'cachelock_file',

                'dir' => 'filelocks',

                'default' => true

            )

        );

        return $writer->generate_configuration_array();

    }

    /**

     * Updates the definition in the configuration from those found in the cache files.

     *

     * @param bool $coreonly Unused.

     */

    public static function update_definitions($coreonly = false) {

        // Nothing to do here.

    }

    /**

     * Locates all of the definition files.

     *

     * @param bool $coreonly Unused.

     * @return array

     */

    protected static function locate_definitions($coreonly = false) {

        return array();

    }

    /**

     * Sets the mappings for a given definition.

     *

     * @param string $definition Unused.

     * @param array $mappings Unused.

     * @throws coding_exception

     */

    public function set_definition_mappings($definition, $mappings) {

        // Nothing to do here.

    }

}