def _cacheSequenceInfoType(self):
hasReset = self.resetFieldName is not None<EOL>hasSequenceId = self.sequenceIdFieldName is not None<EOL>if hasReset and not hasSequenceId:<EOL><INDENT>self._sequenceInfoType = self.SEQUENCEINFO_RESET_ONLY<EOL>self._prevSequenceId = <NUM_LIT:0><EOL><DEDENT>elif not hasReset and hasSequenceId:<EOL><INDENT>self._sequenceInfoType = self.SEQUENCEINFO_SEQUENCEID_ONLY<EOL>self._prevSequenceId = None<EOL><DEDENT>elif hasReset and hasSequenceId:<EOL><INDENT>self._sequenceInfoType = self.SEQUENCEINFO_BOTH<EOL><DEDENT>else:<EOL><INDENT>self._sequenceInfoType = self.SEQUENCEINFO_NONE<EOL><DEDENT>
Figure out whether reset, sequenceId,
        both or neither are present in the data.
        Compute once instead of every time.

        Taken from filesource.py