403 lines
11 KiB
PHP

<?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/>.
/**
* The library file for the static cache store.
*
* This file is part of the static cache store, it contains the API for interacting with an instance of the store.
* This is used as a default cache store within the Cache API. It should never be deleted.
*
* @package cachestore_static
* @category cache
* @copyright 2012 Sam Hemelryk
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/**
* The static data store class
*
* @copyright 2012 Sam Hemelryk
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class static_data_store extends cache_store {
/**
* An array for storage.
* @var array
*/
private static $staticstore = array();
/**
* Returns a static store by reference... REFERENCE SUPER IMPORTANT.
*
* @param string $id
* @return array
*/
protected static function &register_store_id($id) {
if (!array_key_exists($id, self::$staticstore)) {
self::$staticstore[$id] = array();
}
return self::$staticstore[$id];
}
/**
* Flushes the store of all values for belonging to the store with the given id.
* @param string $id
*/
protected static function flush_store_by_id($id) {
unset(self::$staticstore[$id]);
self::$staticstore[$id] = array();
}
/**
* Flushes all of the values from all stores.
*
* @copyright 2012 Sam Hemelryk
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
protected static function flush_store() {
$ids = array_keys(self::$staticstore);
unset(self::$staticstore);
self::$staticstore = array();
foreach ($ids as $id) {
self::$staticstore[$id] = array();
}
}
}
/**
* The static store class.
*
* @copyright 2012 Sam Hemelryk
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class cachestore_static extends static_data_store implements cache_is_key_aware {
/**
* The name of the store
* @var store
*/
protected $name;
/**
* The store id (should be unique)
* @var string
*/
protected $storeid;
/**
* The store we use for data.
* @var array
*/
protected $store;
/**
* The ttl if there is one. Hopefully not.
* @var int
*/
protected $ttl = 0;
/**
* Constructs the store instance.
*
* Noting that this function is not an initialisation. It is used to prepare the store for use.
* The store will be initialised when required and will be provided with a cache_definition at that time.
*
* @param string $name
* @param array $configuration
*/
public function __construct($name, array $configuration = array()) {
$this->name = $name;
}
/**
* Returns the supported features as a combined int.
*
* @param array $configuration
* @return int
*/
public static function get_supported_features(array $configuration = array()) {
return self::SUPPORTS_DATA_GUARANTEE +
self::SUPPORTS_NATIVE_TTL;
}
/**
* Returns the supported modes as a combined int.
*
* @param array $configuration
* @return int
*/
public static function get_supported_modes(array $configuration = array()) {
return self::MODE_REQUEST;
}
/**
* Returns true if the store requirements are met.
*
* @return bool
*/
public static function are_requirements_met() {
return true;
}
/**
* Returns true if the given mode is supported by this store.
*
* @param int $mode One of cache_store::MODE_*
* @return bool
*/
public static function is_supported_mode($mode) {
return ($mode === self::MODE_REQUEST);
}
/**
* Initialises the cache.
*
* Once this has been done the cache is all set to be used.
*
* @param cache_definition $definition
*/
public function initialise(cache_definition $definition) {
$this->storeid = $definition->generate_definition_hash();
$this->store = &self::register_store_id($this->storeid);
$this->ttl = $definition->get_ttl();
}
/**
* Returns true once this instance has been initialised.
*
* @return bool
*/
public function is_initialised() {
return (is_array($this->store));
}
/**
* Returns true if this store instance is ready to be used.
* @return bool
*/
public function is_ready() {
return true;
}
/**
* Retrieves an item from the cache store given its key.
*
* @param string $key The key to retrieve
* @return mixed The data that was associated with the key, or false if the key did not exist.
*/
public function get($key) {
$maxtime = cache::now() - $this->ttl;
if (array_key_exists($key, $this->store)) {
if ($this->ttl == 0) {
return $this->store[$key];
} else if ($this->store[$key][1] >= $maxtime) {
return $this->store[$key][0];
}
}
return false;
}
/**
* Retrieves several items from the cache store in a single transaction.
*
* If not all of the items are available in the cache then the data value for those that are missing will be set to false.
*
* @param array $keys The array of keys to retrieve
* @return array An array of items from the cache. There will be an item for each key, those that were not in the store will
* be set to false.
*/
public function get_many($keys) {
$return = array();
$maxtime = cache::now() - $this->ttl;
foreach ($keys as $key) {
$return[$key] = false;
if (array_key_exists($key, $this->store)) {
if ($this->ttl == 0) {
$return[$key] = $this->store[$key];
} else if ($this->store[$key][1] >= $maxtime) {
$return[$key] = $this->store[$key][0];
}
}
}
return $return;
}
/**
* Sets an item in the cache given its key and data value.
*
* @param string $key The key to use.
* @param mixed $data The data to set.
* @return bool True if the operation was a success false otherwise.
*/
public function set($key, $data) {
if ($this->ttl == 0) {
$this->store[$key] = $data;
} else {
$this->store[$key] = array($data, cache::now());
}
return true;
}
/**
* Sets many items in the cache in a single transaction.
*
* @param array $keyvaluearray An array of key value pairs. Each item in the array will be an associative array with two
* keys, 'key' and 'value'.
* @return int The number of items successfully set. It is up to the developer to check this matches the number of items
* sent ... if they care that is.
*/
public function set_many(array $keyvaluearray) {
$count = 0;
foreach ($keyvaluearray as $pair) {
$this->set($pair['key'], $pair['value']);
$count++;
}
return $count;
}
/**
* Checks if the store has a record for the given key and returns true if so.
*
* @param string $key
* @return bool
*/
public function has($key) {
$maxtime = cache::now() - $this->ttl;
if (array_key_exists($key, $this->store)) {
if ($this->ttl == 0) {
return true;
} else if ($this->store[$key][1] >= $maxtime) {
return true;
}
}
return false;
}
/**
* Returns true if the store contains records for all of the given keys.
*
* @param array $keys
* @return bool
*/
public function has_all(array $keys) {
$maxtime = cache::now() - $this->ttl;
foreach ($keys as $key) {
if (!array_key_exists($key, $this->store)) {
return false;
}
if ($this->ttl != 0 && $this->store[$key][1] < $maxtime) {
return false;
}
}
return true;
}
/**
* Returns true if the store contains records for any of the given keys.
*
* @param array $keys
* @return bool
*/
public function has_any(array $keys) {
$maxtime = cache::now() - $this->ttl;
foreach ($keys as $key) {
if (array_key_exists($key, $this->store) && ($this->ttl == 0 || $this->store[$key][1] >= $maxtime)) {
return true;
}
}
return false;
}
/**
* Deletes an item from the cache store.
*
* @param string $key The key to delete.
* @return bool Returns true if the operation was a success, false otherwise.
*/
public function delete($key) {
$result = isset($this->store[$key]);
unset($this->store[$key]);
return $result;
}
/**
* Deletes several keys from the cache in a single action.
*
* @param array $keys The keys to delete
* @return int The number of items successfully deleted.
*/
public function delete_many(array $keys) {
$count = 0;
foreach ($keys as $key) {
if (isset($this->store[$key])) {
$count++;
}
unset($this->store[$key]);
}
return $count;
}
/**
* Purges the cache deleting all items within it.
*
* @return boolean True on success. False otherwise.
*/
public function purge() {
$this->flush_store_by_id($this->storeid);
$this->store = &self::register_store_id($this->storeid);
return true;
}
/**
* Returns true if the user can add an instance of the store plugin.
*
* @return bool
*/
public static function can_add_instance() {
return false;
}
/**
* Performs any necessary clean up when the store instance is being deleted.
*/
public function instance_deleted() {
$this->purge();
}
/**
* Generates an instance of the cache store that can be used for testing.
*
* @param cache_definition $definition
* @return false
*/
public static function initialise_test_instance(cache_definition $definition) {
// Do something here perhaps.
$cache = new cachestore_static('Static store');
$cache->initialise($definition);
return $cache;
}
/**
* Returns the name of this instance.
* @return string
*/
public function my_name() {
return $this->name;
}
}