function system_cron

Implements hook_cron().

Remove older rows from flood and batch table. Remove old temporary files.

File

modules/system/system.module, line 3079

Code

function system_cron() {
    // Cleanup the flood.
    db_delete('flood')->condition('expiration', REQUEST_TIME, '<')
        ->execute();
    // Remove temporary files that are older than DRUPAL_MAXIMUM_TEMP_FILE_AGE.
    // Use separate placeholders for the status to avoid a bug in some versions
    // of PHP. See http://drupal.org/node/352956.
    $result = db_query('SELECT fid FROM {file_managed} WHERE status <> :permanent AND timestamp < :timestamp', array(
        ':permanent' => FILE_STATUS_PERMANENT,
        ':timestamp' => REQUEST_TIME - DRUPAL_MAXIMUM_TEMP_FILE_AGE,
    ));
    foreach ($result as $row) {
        if ($file = file_load($row->fid)) {
            $references = file_usage_list($file);
            if (empty($references)) {
                if (!file_delete($file)) {
                    watchdog('file system', 'Could not delete temporary file "%path" during garbage collection', array(
                        '%path' => $file->uri,
                    ), WATCHDOG_ERROR);
                }
            }
            else {
                watchdog('file system', 'Did not delete temporary file "%path" during garbage collection, because it is in use by the following modules: %modules.', array(
                    '%path' => $file->uri,
                    '%modules' => implode(', ', array_keys($references)),
                ), WATCHDOG_INFO);
            }
        }
    }
    // Delete expired cache entries.
    // Avoid invoking hook_flush_cashes() on every cron run because some modules
    // use this hook to perform expensive rebuilding operations (which are only
    // designed to happen on full cache clears), rather than just returning a
    // list of cache tables to be cleared.
    $cache_object = cache_get('system_cache_tables');
    if (empty($cache_object)) {
        $core = array(
            'cache',
            'cache_path',
            'cache_filter',
            'cache_page',
            'cache_form',
            'cache_menu',
        );
        $cache_tables = array_merge(module_invoke_all('flush_caches'), $core);
        cache_set('system_cache_tables', $cache_tables);
    }
    else {
        $cache_tables = $cache_object->data;
    }
    foreach ($cache_tables as $table) {
        cache_clear_all(NULL, $table);
    }
    // Cleanup the batch table and the queue for failed batches.
    db_delete('batch')->condition('timestamp', REQUEST_TIME - 864000, '<')
        ->execute();
    db_delete('queue')->condition('created', REQUEST_TIME - 864000, '<')
        ->condition('name', 'drupal_batch:%', 'LIKE')
        ->execute();
    // Reset expired items in the default queue implementation table. If that's
    // not used, this will simply be a no-op.
    db_update('queue')->fields(array(
        'expire' => 0,
    ))
        ->condition('expire', 0, '<>')
        ->condition('expire', REQUEST_TIME, '<')
        ->execute();
}