// don't snapshot if we've been asked not to,
        // or if we cannot because  we are querying, sorting, or if the collection is a view
        if !exp.InputOpts.ForceTableScan && len(query) == 0 && exp.InputOpts != nil && exp.InputOpts.Sort == "" && !collInfo.IsView() && !collInfo.IsSystemCollection() {
                flags = flags | db.Snapshot
        }

    if (query.getQueryRequest().isSnapshot()) {
        RARELY {
            warning() << "The snapshot option is deprecated. See "
                         "http://dochub.mongodb.org/core/snapshot-deprecation";
        }