/**
* Returns the item from the static acceleration array if it exists there.
*
* @param string $key The parsed key
* @return mixed|false The data from the static acceleration array or false if it wasn't there.
*/
protected function get_from_persist_cache($key)
{
// This method of checking if an array was supplied is faster than is_array.
if ($key === (array) $key) {
$key = $key['key'];
}
// This isset check is faster than array_key_exists but will return false
// for null values, meaning null values will come from backing store not
// the static acceleration array. We think this okay because null usage should be
// very rare (see comment in MDL-39472).
if (!$this->staticacceleration || !isset($this->staticaccelerationarray[$key])) {
$result = false;
} else {
$data = $this->staticaccelerationarray[$key];
if (!$this->has_a_ttl() || !$data instanceof cache_ttl_wrapper) {
if ($data instanceof cache_cached_object) {
$data = $data->restore_object();
}
$result = $data;
} else {
if ($data->has_expired()) {
$this->delete_from_persist_cache($key);
$result = false;
} else {
if ($data instanceof cache_cached_object) {
$data = $data->restore_object();
}
$result = $data->data;
}
}
}
if ($result) {
if ($this->perfdebug) {
cache_helper::record_cache_hit('** static acceleration **', $this->definition->get_id());
}
if ($this->staticaccelerationsize > 1 && $this->staticaccelerationcount > 1) {
// Check to see if this is the last item on the static acceleration keys array.
if (end($this->staticaccelerationkeys) !== $key) {
// It isn't the last item.
// Move the item to the end of the array so that it is last to be removed.
unset($this->staticaccelerationkeys[$key]);
$this->staticaccelerationkeys[$key] = $key;
}
}
return $result;
} else {
if ($this->perfdebug) {
cache_helper::record_cache_miss('** static acceleration **', $this->definition->get_id());
}
return false;
}
}
/**
* Returns the item from the persist cache if it exists there.
*
* @param string $key The parsed key
* @return mixed|false The data from the persist cache or false if it wasn't there.
*/
protected function get_from_persist_cache($key)
{
if (is_array($key)) {
$key = $key['key'];
}
if (!$this->persist || !array_key_exists($key, $this->persistcache)) {
$result = false;
} else {
$data = $this->persistcache[$key];
if (!$this->has_a_ttl() || !$data instanceof cache_ttl_wrapper) {
if ($data instanceof cache_cached_object) {
$data = $data->restore_object();
}
$result = $data;
} else {
if ($data->has_expired()) {
$this->delete_from_persist_cache($key);
$result = false;
} else {
if ($data instanceof cache_cached_object) {
$data = $data->restore_object();
}
$result = $data->data;
}
}
}
if ($result) {
if ($this->perfdebug) {
cache_helper::record_cache_hit('** static persist **', $this->definition->get_id());
}
return $result;
} else {
if ($this->perfdebug) {
cache_helper::record_cache_miss('** static persist **', $this->definition->get_id());
}
return false;
}
}
/**
* 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->name . '-' . $definition->get_id());
$this->ttl = $definition->get_ttl();
$maxsize = $definition->get_maxsize();
if ($maxsize !== null) {
// Must be a positive int.
$this->maxsize = abs((int) $maxsize);
$this->storecount = count($this->store);
}
$this->check_ttl();
}
/**
* Hashes a descriptive key to make it shorter and still unique.
* @param string|int $key
* @param cache_definition $definition
* @return string
*/
public static function hash_key($key, cache_definition $definition)
{
if ($definition->uses_simple_keys()) {
if (debugging() && preg_match('#[^a-zA-Z0-9_]#', $key)) {
throw new coding_exception('Cache definition ' . $definition->get_id() . ' requires simple keys. Invalid key provided.', $key);
}
// We put the key first so that we can be sure the start of the key changes.
return (string) $key . '-' . $definition->generate_single_key_prefix();
}
$key = $definition->generate_single_key_prefix() . '-' . $key;
return sha1($key);
}
/**
* Returns an array of cache stores that have been initialised for use in definitions.
* @param cache_definition $definition
* @return array
*/
public function get_store_instances_in_use(cache_definition $definition)
{
$id = $definition->get_id();
if (!isset($this->definitionstores[$id])) {
return array();
}
return $this->definitionstores[$id];
}
/**
* Gets all of the stores that are to be used for the given definition.
*
* @param cache_definition $definition
* @return array
*/
public function get_stores_for_definition(cache_definition $definition)
{
// Check if MUC has been disabled.
$factory = cache_factory::instance();
if ($factory->stores_disabled()) {
// Yip its been disabled.
// To facilitate this we are going to always return an empty array of stores to use.
// This will force all cache instances to use the cachestore_dummy.
// MUC will still be used essentially so that code using it will still continue to function but because no cache stores
// are being used interaction with MUC will be purely based around a static var.
return array();
}
$availablestores = $this->get_stores($definition->get_mode(), $definition->get_requirements_bin());
$stores = array();
$id = $definition->get_id();
// Now get any mappings and give them priority.
foreach ($this->configdefinitionmappings as $mapping) {
if ($mapping['definition'] !== $id) {
continue;
}
$storename = $mapping['store'];
if (!array_key_exists($storename, $availablestores)) {
continue;
}
if (array_key_exists($storename, $stores)) {
$store = $stores[$storename];
unset($stores[$storename]);
$stores[$storename] = $store;
} else {
$stores[$storename] = $availablestores[$storename];
}
}
if (empty($stores) && !$definition->is_for_mappings_only()) {
$mode = $definition->get_mode();
// Load the default stores.
foreach ($this->configmodemappings as $mapping) {
if ($mapping['mode'] === $mode && array_key_exists($mapping['store'], $availablestores)) {
$store = $availablestores[$mapping['store']];
if (empty($store['mappingsonly'])) {
$stores[$mapping['store']] = $store;
}
}
}
}
return $stores;
}
/**
* 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->definition = $definition;
$hash = preg_replace('#[^a-zA-Z0-9]+#', '_', $this->definition->get_id());
$this->path = $this->filestorepath . '/' . $hash;
make_writable_directory($this->path);
if ($this->prescan && $definition->get_mode() !== self::MODE_REQUEST) {
$this->prescan = false;
}
if ($this->prescan) {
$this->prescan_keys();
}
}
/**
* 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();
$this->store =& self::register_store_id($definition->get_id());
$this->ttl = $definition->get_ttl();
}
