Defines a stub cache implementation to be used during installation.
The stub implementation is needed when database access is not yet available. Because Drupal's caching system never requires that cached data be present, these stub functions can short-circuit the process and sidestep the need for any persistent storage. Obviously, using this cache implementation during normal operations would have a negative impact on performance.
Hierarchy
- class \DrupalDatabaseCache implements DrupalCacheInterface
- class \DrupalFakeCache implements DrupalCacheInterface
Expanded class hierarchy of DrupalFakeCache
1 string reference to 'DrupalFakeCache'
- install_begin_request in includes/
install.core.inc - Begins an installation request, modifying the installation state as needed.
File
- includes/
cache-install.inc, line 17 - Provides a stub cache implementation to be used during installation.
View source
class DrupalFakeCache extends DrupalDatabaseCache implements DrupalCacheInterface {
/**
* Overrides DrupalDatabaseCache::get().
*/
function get($cid) {
return FALSE;
}
/**
* Overrides DrupalDatabaseCache::getMultiple().
*/
function getMultiple(&$cids) {
return array();
}
/**
* Overrides DrupalDatabaseCache::set().
*/
function set($cid, $data, $expire = CACHE_PERMANENT) {
}
/**
* Overrides DrupalDatabaseCache::clear().
*/
function clear($cid = NULL, $wildcard = FALSE) {
// If there is a database cache, attempt to clear it whenever possible. The
// reason for doing this is that the database cache can accumulate data
// during installation due to any full bootstraps that may occur at the
// same time (for example, Ajax requests triggered by the installer). If we
// didn't try to clear it whenever this function is called, the data in the
// cache would become stale; for example, the installer sometimes calls
// variable_set(), which updates the {variable} table and then clears the
// cache to make sure that the next page request picks up the new value.
// Not actually clearing the cache here therefore leads old variables to be
// loaded on the first page requests after installation, which can cause
// subtle bugs, some of which would not be fixed unless the site
// administrator cleared the cache manually.
try {
if (class_exists('Database')) {
parent::clear($cid, $wildcard);
}
} catch (Exception $e) {
}
}
/**
* Overrides DrupalDatabaseCache::isEmpty().
*/
function isEmpty() {
return TRUE;
}
}
