/**
* Performs a "check and set" to store data.
*
* The set will be successful only if the no other request has updated the value since it was fetched since
* this request.
*
* @link http://www.php.net/manual/en/memcached.cas.php
*
* @param float $cas_token Unique value associated with the existing item. Generated by memcached.
* @param string $key The key under which to store the value.
* @param mixed $value The value to store.
* @param string $group The group value appended to the $key.
* @param int $expiration The expiration time, defaults to 0.
* @param string $server_key The key identifying the server to store the value on.
* @param bool $byKey True to store in internal cache by key; false to not store by key
* @return bool Returns TRUE on success or FALSE on failure.
*/
public function cas($cas_token, $key, $value, $group = 'default', $expiration = 0, $server_key = '', $byKey = false)
{
$derived_key = $this->buildKey($key, $group);
$expiration = $this->sanitize_expiration($expiration);
/**
* If group is a non-Memcached group, save to runtime cache, not Memcached. Note
* that since check and set cannot be emulated in the run time cache, this value
* operation is treated as a normal "add" for no_mc_groups.
*/
if (in_array($group, $this->no_mc_groups)) {
$this->add_to_internal_cache($derived_key, $value);
return true;
}
// Save to Memcached
if (false !== $byKey) {
$result = $this->mc->casByKey($cas_token, $server_key, $derived_key, $value, $expiration);
} else {
$result = $this->mc->cas($cas_token, $derived_key, $value, $expiration);
}
// Store in runtime cache if cas was successful
if (Memcached::RES_SUCCESS === $this->getResultCode()) {
$this->add_to_internal_cache($derived_key, $value);
}
return $result;
}
/**
* @inheritdoc
*/
public function casByKey($cas_token, $server_key, $key, $value, $expiration = null)
{
$key = $this->prefix . $key;
return parent::casByKey($cas_token, $server_key, $key, $value, $expiration = null);
}
