Core changes:
* avoid package-colliding variable naming
* avoid using pointers to IDs where unnecessary
* avoid using `idSDK` import alias pattern
* use `EncodeToString` for protocol string calculation and `String` for
printing
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `DB.IterateCoveredByTombstones` to not pass locked objects to the
handler. The method is used by GC, therefore it will not consider locked
objects as candidates for deletion even if their tombstone is expired.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Make `DB.IterateExpired` to not pass locked objects to the handler. The
method is used by GC, therefore it will not consider them as candidates
for deletion.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement `DB.Lock` method which marks list of the objects as locked by
another object. Only regular objects can be locked.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement `DB.IterateCoveredByTombstones` method that iterates over graves
and handles all objects under one of the tombstones.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement `DB.IterateExpired` method that iterates over the objects in
metabase that are expired at particular epoch.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
