question about optime,timestamp and log

Hi,
1.I noticed that BSONElement had the _opTime() method in the early version to get an OpTime type from BSONElement type (e.g. "ts" field in oplog), and now only timestamp() ,and Timestamp_t object could't change value.
private:
const uint32_t _seconds;
const uint32_t _increment;

2. the log util seems unable to use ?Could I use LOG() or Log() or something.

thanks.