Sam Hemelryk
acf49f4b9a
Bug: There was no way to create an instance of a lock plugin for use within Moodle. Solution: Implemented management interfaces as part of cache/admin.php to allow for instances to be added and deleted. This was done in along the same lines of adding store instances.
561 lines
19 KiB
PHP
561 lines
19 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* Cache configuration reader
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*
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* This file is part of Moodle's cache API, affectionately called MUC.
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* It contains the components that are requried in order to use caching.
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*
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* @package core
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* @category cache
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* @copyright 2012 Sam Hemelryk
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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defined('MOODLE_INTERNAL') || die();
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/**
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* Cache configuration reader.
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*
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* This class is used to interact with the cache's configuration.
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* The configuration is stored in the Moodle data directory.
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*
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* @package core
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* @category cache
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* @copyright 2012 Sam Hemelryk
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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class cache_config {
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/**
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* The configured stores
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* @var array
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*/
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protected $configstores = array();
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/**
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* The configured mode mappings
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* @var array
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*/
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protected $configmodemappings = array();
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/**
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* The configured definitions as picked up from cache.php files
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* @var array
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*/
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protected $configdefinitions = array();
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/**
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* The definition mappings that have been configured.
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* @var array
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*/
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protected $configdefinitionmappings = array();
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/**
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* An array of configured cache lock instances.
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* @var array
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*/
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protected $configlocks = array();
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/**
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* The site identifier used when the cache config was last saved.
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* @var string
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*/
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protected $siteidentifier = null;
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/**
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* Please use cache_config::instance to get an instance of the cache config that is ready to be used.
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*/
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public function __construct() {
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// Nothing to do here but look pretty.
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}
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/**
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* Gets an instance of the cache_configuration class.
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*
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* @return cache_config
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*/
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public static function instance() {
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$factory = cache_factory::instance();
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return $factory->create_config_instance();
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}
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/**
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* Checks if the configuration file exists.
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*
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* @return bool True if it exists
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*/
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public static function config_file_exists() {
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// Allow for late static binding.
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return file_exists(self::get_config_file_path());
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}
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/**
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* Returns the expected path to the configuration file.
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*
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* @return string The absolute path
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*/
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protected static function get_config_file_path() {
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global $CFG;
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if (!empty($CFG->altcacheconfigpath)) {
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$path = $CFG->altcacheconfigpath;
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if (is_dir($path) && is_writable($path)) {
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// Its a writable directory, thats fine.
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return $path.'/cacheconfig.php';
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} else if (is_writable(dirname($path)) && (!file_exists($path) || is_writable($path))) {
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// Its a file, either it doesn't exist and the directory is writable or the file exists and is writable.
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return $path;
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}
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}
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// Return the default location within dataroot.
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return $CFG->dataroot.'/muc/config.php';
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}
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/**
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* Loads the configuration file and parses its contents into the expected structure.
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*
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* @param array|false $configuration Can be used to force a configuration. Should only be used when truly required.
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* @return boolean
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*/
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public function load($configuration = false) {
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global $CFG;
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if ($configuration === false) {
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$configuration = $this->include_configuration();
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}
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$this->configstores = array();
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$this->configdefinitions = array();
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$this->configlocks = array();
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$this->configmodemappings = array();
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$this->configdefinitionmappings = array();
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$this->configlockmappings = array();
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$siteidentifier = 'unknown';
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if (array_key_exists('siteidentifier', $configuration)) {
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$siteidentifier = $configuration['siteidentifier'];
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}
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$this->siteidentifier = $siteidentifier;
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// Filter the lock instances.
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$defaultlock = null;
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foreach ($configuration['locks'] as $conf) {
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if (!is_array($conf)) {
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// Something is very wrong here.
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continue;
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}
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if (!array_key_exists('name', $conf)) {
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// Not a valid definition configuration.
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continue;
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}
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$name = $conf['name'];
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if (array_key_exists($name, $this->configlocks)) {
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debugging('Duplicate cache lock detected. This should never happen.', DEBUG_DEVELOPER);
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continue;
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}
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$conf['default'] = (!empty($conf['default']));
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if ($defaultlock === null || $conf['default']) {
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$defaultlock = $name;
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}
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$this->configlocks[$name] = $conf;
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}
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// Filter the stores.
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$availableplugins = cache_helper::early_get_cache_plugins();
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foreach ($configuration['stores'] as $store) {
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if (!is_array($store) || !array_key_exists('name', $store) || !array_key_exists('plugin', $store)) {
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// Not a valid instance configuration.
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debugging('Invalid cache store in config. Missing name or plugin.', DEBUG_DEVELOPER);
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continue;
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}
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$plugin = $store['plugin'];
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$class = 'cachestore_'.$plugin;
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$exists = array_key_exists($plugin, $availableplugins);
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if (!$exists) {
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// Not a valid plugin, or has been uninstalled, just skip it an carry on.
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debugging('Invalid cache store in config. Not an available plugin.', DEBUG_DEVELOPER);
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continue;
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}
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$file = $CFG->dirroot.'/cache/stores/'.$plugin.'/lib.php';
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if (!class_exists($class) && file_exists($file)) {
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require_once($file);
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}
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if (!class_exists($class)) {
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continue;
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}
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if (!array_key_exists('cache_store', class_parents($class))) {
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continue;
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}
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if (!array_key_exists('configuration', $store) || !is_array($store['configuration'])) {
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$store['configuration'] = array();
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}
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$store['class'] = $class;
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$store['default'] = !empty($store['default']);
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if (!array_key_exists('lock', $store) || !array_key_exists($store['lock'], $this->configlocks)) {
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$store['lock'] = $defaultlock;
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}
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$this->configstores[$store['name']] = $store;
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}
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// Filter the definitions.
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foreach ($configuration['definitions'] as $id => $conf) {
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if (!is_array($conf)) {
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// Something is very wrong here.
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continue;
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}
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if (!array_key_exists('mode', $conf) || !array_key_exists('component', $conf) || !array_key_exists('area', $conf)) {
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// Not a valid definition configuration.
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continue;
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}
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if (array_key_exists($id, $this->configdefinitions)) {
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debugging('Duplicate cache definition detected. This should never happen.', DEBUG_DEVELOPER);
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continue;
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}
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$conf['mode'] = (int)$conf['mode'];
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if ($conf['mode'] < cache_store::MODE_APPLICATION || $conf['mode'] > cache_store::MODE_REQUEST) {
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// Invalid cache mode used for the definition.
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continue;
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}
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$this->configdefinitions[$id] = $conf;
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}
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// Filter the mode mappings.
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foreach ($configuration['modemappings'] as $mapping) {
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if (!is_array($mapping) || !array_key_exists('mode', $mapping) || !array_key_exists('store', $mapping)) {
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// Not a valid mapping configuration.
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debugging('A cache mode mapping entry is invalid.', DEBUG_DEVELOPER);
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continue;
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}
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if (!array_key_exists($mapping['store'], $this->configstores)) {
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// Mapped array instance doesn't exist.
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debugging('A cache mode mapping exists for a mode or store that does not exist.', DEBUG_DEVELOPER);
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continue;
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}
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$mapping['mode'] = (int)$mapping['mode'];
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if ($mapping['mode'] < 0 || $mapping['mode'] > 4) {
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// Invalid cache type used for the mapping.
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continue;
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}
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if (!array_key_exists('sort', $mapping)) {
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$mapping['sort'] = 0;
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}
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$this->configmodemappings[] = $mapping;
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}
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// Filter the definition mappings.
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foreach ($configuration['definitionmappings'] as $mapping) {
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if (!is_array($mapping) || !array_key_exists('definition', $mapping) || !array_key_exists('store', $mapping)) {
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// Not a valid mapping configuration.
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continue;
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}
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if (!array_key_exists($mapping['store'], $this->configstores)) {
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// Mapped array instance doesn't exist.
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continue;
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}
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if (!array_key_exists($mapping['definition'], $this->configdefinitions)) {
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// Mapped array instance doesn't exist.
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continue;
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}
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if (!array_key_exists('sort', $mapping)) {
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$mapping['sort'] = 0;
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}
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$this->configdefinitionmappings[] = $mapping;
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}
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usort($this->configmodemappings, array($this, 'sort_mappings'));
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usort($this->configdefinitionmappings, array($this, 'sort_mappings'));
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return true;
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}
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/**
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* Returns the site identifier used by the cache API.
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* @return string
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*/
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public function get_site_identifier() {
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return $this->siteidentifier;
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}
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/**
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* Includes the configuration file and makes sure it contains the expected bits.
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*
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* You need to ensure that the config file exists before this is called.
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*
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* @return array
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* @throws cache_exception
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*/
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protected function include_configuration() {
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$configuration = array();
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$cachefile = self::get_config_file_path();
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if (!file_exists($cachefile)) {
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throw new cache_exception('Default cache config could not be found. It should have already been created by now.');
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}
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include($cachefile);
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if (!is_array($configuration)) {
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throw new cache_exception('Invalid cache configuration file');
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}
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if (!array_key_exists('stores', $configuration) || !is_array($configuration['stores'])) {
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$configuration['stores'] = array();
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}
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if (!array_key_exists('modemappings', $configuration) || !is_array($configuration['modemappings'])) {
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$configuration['modemappings'] = array();
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}
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if (!array_key_exists('definitions', $configuration) || !is_array($configuration['definitions'])) {
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$configuration['definitions'] = array();
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}
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if (!array_key_exists('definitionmappings', $configuration) || !is_array($configuration['definitionmappings'])) {
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$configuration['definitionmappings'] = array();
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}
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if (!array_key_exists('locks', $configuration) || !is_array($configuration['locks'])) {
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$configuration['locks'] = array();
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}
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return $configuration;
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}
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/**
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* Used to sort cache config arrays based upon a sort key.
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*
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* Highest number at the top.
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*
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* @param array $a
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* @param array $b
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* @return int
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*/
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protected function sort_mappings(array $a, array $b) {
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if ($a['sort'] == $b['sort']) {
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return 0;
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}
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return ($a['sort'] < $b['sort']) ? 1 : -1;
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}
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/**
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* Gets a definition from the config given its name.
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*
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* @param string $id
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* @return bool
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*/
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public function get_definition_by_id($id) {
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if (array_key_exists($id, $this->configdefinitions)) {
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return $this->configdefinitions[$id];
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}
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return false;
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}
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/**
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* Returns all the known definitions.
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*
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* @return array
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*/
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public function get_definitions() {
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return $this->configdefinitions;
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}
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/**
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* Returns the definitions mapped into the given store name.
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*
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* @param string $storename
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* @return array Associative array of definitions, id=>definition
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*/
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public static function get_definitions_by_store($storename) {
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$definitions = array();
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$config = cache_config::instance();
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$stores = $config->get_all_stores();
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if (!array_key_exists($storename, $stores)) {
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// The store does not exist.
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return false;
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}
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$defmappings = $config->get_definition_mappings();
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// Create an associative array for the definition mappings.
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$thedefmappings = array();
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foreach ($defmappings as $defmapping) {
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$thedefmappings[$defmapping['definition']] = $defmapping;
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}
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// Search for matches in default mappings.
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$defs = $config->get_definitions();
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foreach($config->get_mode_mappings() as $modemapping) {
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if ($modemapping['store'] !== $storename) {
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continue;
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}
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foreach($defs as $id => $definition) {
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if ($definition['mode'] !== $modemapping['mode']) {
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continue;
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}
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// Exclude custom definitions mapping: they will be managed few lines below.
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if (array_key_exists($id, $thedefmappings)) {
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continue;
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}
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$definitions[$id] = $definition;
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}
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}
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// Search for matches in the custom definitions mapping
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foreach ($defmappings as $defmapping) {
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if ($defmapping['store'] !== $storename) {
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continue;
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}
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$definition = $config->get_definition_by_id($defmapping['definition']);
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if ($definition) {
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$definitions[$defmapping['definition']] = $definition;
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}
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}
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return $definitions;
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}
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/**
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* Returns all of the stores that are suitable for the given mode and requirements.
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*
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* @param int $mode One of cache_store::MODE_*
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* @param int $requirements The requirements of the cache as a binary flag
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* @return array An array of suitable stores.
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*/
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public function get_stores($mode, $requirements = 0) {
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$stores = array();
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foreach ($this->configstores as $name => $store) {
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// If the mode is supported and all of the requirements are provided features.
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if (($store['modes'] & $mode) && ($store['features'] & $requirements) === $requirements) {
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$stores[$name] = $store;
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}
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}
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return $stores;
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}
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/**
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* Gets all of the stores that are to be used for the given definition.
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*
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* @param cache_definition $definition
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* @return array
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*/
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public function get_stores_for_definition(cache_definition $definition) {
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// Check if MUC has been disabled.
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$factory = cache_factory::instance();
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if ($factory->stores_disabled()) {
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// Yip its been disabled.
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// To facilitate this we are going to always return an empty array of stores to use.
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// This will force all cache instances to use the cachestore_dummy.
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// MUC will still be used essentially so that code using it will still continue to function but because no cache stores
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// are being used interaction with MUC will be purely based around a static var.
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return array();
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}
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$availablestores = $this->get_stores($definition->get_mode(), $definition->get_requirements_bin());
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$stores = array();
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$id = $definition->get_id();
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// Now get any mappings and give them priority.
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foreach ($this->configdefinitionmappings as $mapping) {
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if ($mapping['definition'] !== $id) {
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continue;
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}
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$storename = $mapping['store'];
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if (!array_key_exists($storename, $availablestores)) {
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continue;
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}
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if (array_key_exists($storename, $stores)) {
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$store = $stores[$storename];
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unset($stores[$storename]);
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$stores[$storename] = $store;
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} else {
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$stores[$storename] = $availablestores[$storename];
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}
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}
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if (empty($stores) && !$definition->is_for_mappings_only()) {
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$mode = $definition->get_mode();
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// Load the default stores.
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foreach ($this->configmodemappings as $mapping) {
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if ($mapping['mode'] === $mode && array_key_exists($mapping['store'], $availablestores)) {
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$store = $availablestores[$mapping['store']];
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if (empty($store['mappingsonly'])) {
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$stores[$mapping['store']] = $store;
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}
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}
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}
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}
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return $stores;
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}
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/**
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* Returns all of the configured stores
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* @return array
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*/
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public function get_all_stores() {
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return $this->configstores;
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}
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/**
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* Returns all of the configured mode mappings
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* @return array
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*/
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public function get_mode_mappings() {
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return $this->configmodemappings;
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}
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/**
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* Returns all of the known definition mappings.
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* @return array
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*/
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public function get_definition_mappings() {
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return $this->configdefinitionmappings;
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}
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/**
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* Returns an array of the configured locks.
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* @return array Array of name => config
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*/
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public function get_locks() {
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return $this->configlocks;
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}
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/**
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* Returns the lock store configuration to use with a given store.
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* @param string $storename
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* @return array
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* @throws cache_exception
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*/
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public function get_lock_for_store($storename) {
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if (array_key_exists($storename, $this->configstores)) {
|
|
if (array_key_exists($this->configstores[$storename]['lock'], $this->configlocks)) {
|
|
$lock = $this->configstores[$storename]['lock'];
|
|
return $this->configlocks[$lock];
|
|
}
|
|
}
|
|
return $this->get_default_lock();
|
|
}
|
|
|
|
/**
|
|
* Gets the default lock instance.
|
|
*
|
|
* @return array
|
|
* @throws cache_exception
|
|
*/
|
|
public function get_default_lock() {
|
|
foreach ($this->configlocks as $lockconf) {
|
|
if (!empty($lockconf['default'])) {
|
|
return $lockconf;
|
|
}
|
|
}
|
|
throw new cache_exception('ex_nodefaultlock');
|
|
}
|
|
} |