Implements DrupalCacheInterface::clear().

Parameters

$cid: If set, the cache ID or an array of cache IDs. Otherwise, all cache entries that can expire are deleted. The $wildcard argument will be ignored if set to NULL.

$wildcard: If TRUE, the $cid argument must contain a string value and cache IDs starting with $cid are deleted in addition to the exact cache ID specified by $cid. If $wildcard is TRUE and $cid is '*', the entire cache is emptied.

Overrides DrupalCacheInterface::clear

1 call to DrupalDatabaseCache::clear()

DrupalFakeCache::clear in includes/cache-install.inc

Overrides DrupalDatabaseCache::clear().

1 method overrides DrupalDatabaseCache::clear()

DrupalFakeCache::clear in includes/cache-install.inc

Overrides DrupalDatabaseCache::clear().

File

includes/cache.inc, line 487

Class

DrupalDatabaseCache

Defines a default cache implementation.

Code

function clear($cid = NULL, $wildcard = FALSE) {
 global $user;
 if (empty($cid)) {
 if (variable_get ('cache_lifetime', 0)) {
 // We store the time in the current user's session. We then simulate
 // that the cache was flushed for this user by not returning cached
 // data that was cached before the timestamp.
 $_SESSION['cache_expiration'][$this->bin ] = REQUEST_TIME ;
 $cache_flush = variable_get ('cache_flush_' . $this->bin , 0);
 if ($cache_flush == 0) {
 // This is the first request to clear the cache, start a timer.
 variable_set ('cache_flush_' . $this->bin , REQUEST_TIME );
 }
 elseif (REQUEST_TIME  > $cache_flush + variable_get ('cache_lifetime', 0)) {
 // Clear the cache for everyone, cache_lifetime seconds have
 // passed since the first request to clear the cache.
 db_delete ($this->bin )
 ->condition ('expire', CACHE_PERMANENT , '<>')
 ->condition ('expire', REQUEST_TIME , '<')
 ->execute ();
 variable_set ('cache_flush_' . $this->bin , 0);
 }
 }
 else {
 // No minimum cache lifetime, flush all temporary cache entries now.
 db_delete ($this->bin )
 ->condition ('expire', CACHE_PERMANENT , '<>')
 ->condition ('expire', REQUEST_TIME , '<')
 ->execute ();
 }
 }
 else {
 if ($wildcard) {
 if ($cid == '*') {
 // Check if $this->bin is a cache table before truncating. Other
 // cache_clear_all() operations throw a PDO error in this situation,
 // so we don't need to verify them first. This ensures that non-cache
 // tables cannot be truncated accidentally.
 if ($this->isValidBin ()) {
 db_truncate ($this->bin )
 ->execute ();
 }
 else {
 throw new Exception(t ('Invalid or missing cache bin specified: %bin', array(
 '%bin' => $this->bin ,
 )));
 }
 }
 else {
 db_delete ($this->bin )
 ->condition ('cid', db_like ($cid) . '%', 'LIKE')
 ->execute ();
 }
 }
 elseif (is_array ($cid)) {
 // Delete in chunks when a large array is passed.
 do {
 db_delete ($this->bin )
 ->condition ('cid', array_splice ($cid, 0, 1000), 'IN')
 ->execute ();
 } while (count ($cid));
 }
 else {
 db_delete ($this->bin )
 ->condition ('cid', $cid)
 ->execute ();
 }
 }
}

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