Expire data from the cache. If called without arguments, expirable entries will be cleared from the cache_page and cache_block tables.

Parameters

$cid: If set, the cache ID to delete. Otherwise, all cache entries that can expire are deleted.

$table: If set, the table $table to delete from. Mandatory argument if $cid is set.

$wildcard: If $wildcard is TRUE, cache IDs starting with $cid are deleted in addition to the exact cache ID specified by $cid. If $wildcard is TRUE and $cid is '*' then the entire table $table is emptied.

File

drupal-6.x/includes/cache.inc, line 136

Code

function cache_clear_all($cid = NULL, $table = NULL, $wildcard = FALSE) {
  global $user;

  if (!isset($cid) && !isset($table)) {
    // Clear the block cache first, so stale data will
    // not end up in the page cache.
    cache_clear_all(NULL, 'cache_block');
    cache_clear_all(NULL, 'cache_page');
    return;
  }

  if (empty($cid)) {
    if (variable_get('cache_lifetime', 0)) {
      // We store the time in the current user's $user->cache variable which
      // will be saved into the sessions table by sess_write(). We then
      // simulate that the cache was flushed for this user by not returning
      // cached data that was cached before the timestamp.
      $user->cache = time();

      $cache_flush = variable_get('cache_flush_' . $table, 0);
      if ($cache_flush == 0) {
        // This is the first request to clear the cache, start a timer.
        variable_set('cache_flush_' . $table, time());
      }
      else if (time() > ($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_query("DELETE FROM {" . $table . "} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
        variable_set('cache_flush_' . $table, 0);
      }
    }
    else {
      // No minimum cache lifetime, flush all temporary cache entries now.
      db_query("DELETE FROM {" . $table . "} WHERE expire != %d AND expire < %d", CACHE_PERMANENT, time());
    }
  }
  else {
    if ($wildcard) {
      if ($cid == '*') {
        db_query("TRUNCATE TABLE {" . $table . "}");
      }
      else {
        db_query("DELETE FROM {" . $table . "} WHERE cid LIKE '%s%%'", $cid);
      }
    }
    else {
      db_query("DELETE FROM {" . $table . "} WHERE cid = '%s'", $cid);
    }
  }
}