module FDB::Locality

def self.get_addresses_for_key(db_or_tr, key)
  key = FDB.key_to_bytes(key)
  db_or_tr.transact do |tr|
    FutureStringArray.new(FDBC.fdb_transaction_get_addresses_for_key(tr.tpointer, key, key.bytesize))
  end
end

def self.get_boundary_keys(db_or_tr, bkey, ekey)
  bkey = FDB.key_to_bytes(bkey).dup.force_encoding('BINARY')
  ekey = FDB.key_to_bytes(ekey).dup.force_encoding('BINARY')
  if db_or_tr.is_a? Transaction
    tr = db_or_tr.db.create_transaction
    tr.set_read_version db_or_tr.get_read_version
  else
    tr = db_or_tr.create_transaction
  end
  tr.options.set_read_system_keys
  tr.options.set_lock_aware
  lastbkey = bkey
  kvs = tr.snapshot.get_range("\xff/keyServers/"+bkey, "\xff/keyServers/"+ekey)
  y = Enumerator.new do |yielder|
    _tr = tr
    _bkey = bkey
    _ekey = ekey
    _lastbkey = lastbkey
    _kvs = kvs
    while _bkey < _ekey
      begin
        _kvs.each do |kv|
          yielder.yield kv.key.byteslice(13..-1)
          _bkey = kv.key.byteslice(13..-1) + "\x00"
        end
        _bkey = _ekey
      rescue FDB::Error => e
        if e.code == 1007 and _bkey != _lastbkey # if we get a transaction_too_old and *something* has happened, then we are no longer transactional
          _tr = _tr.db.create_transaction
        else
          _tr.on_error(e).wait
        end
        # we either created a new transaction or (implicitly) reset the one we had...
        _tr.options.set_read_system_keys
        _lastbkey = _bkey
        _kvs = _tr.snapshot.get_range("\xff/keyServers/" + _bkey, "\xff/keyServers/" + _ekey)
      end
    end
  end
  return y
end