private void readCommitLogSegment()

in cassandra-four-zero/src/main/java/org/apache/cassandra/db/commitlog/BufferingCommitLogReader.java [224:280]
45 lines of code
8 McCabe index (conditional complexity)

    private void readCommitLogSegment() throws IOException
    {
        long startTimeNanos = System.nanoTime();
        SeekableCommitLogSegmentReader segmentReader;
        try
        {
            segmentReader = new SeekableCommitLogSegmentReader(this, descriptor, reader, logger, false);
        }
        catch (Exception exception)
        {
            handleUnrecoverableError(new CommitLogReadException(
                    String.format("Unable to create segment reader for commit log file: %s", exception),
                    CommitLogReadErrorReason.UNRECOVERABLE_UNKNOWN_ERROR,
                    false));
            return;
        }

        try
        {
            if (descriptor.id == highWaterMark.segmentId() && reader.getFilePointer() < highWaterMark.position())
            {
                segmentReader.seek(highWaterMark.position());
            }

            for (CommitLogSegmentReader.SyncSegment syncSegment : segmentReader)
            {
                // Only tolerate truncationSerializationHeader if we allow in both global and segment
                // statusTracker.tolerateErrorsInSection = tolerateTruncation && syncSegment.toleratesErrorsInSection;

                statusTracker.errorContext = String.format("Next section at %d in %s",
                                                           syncSegment.fileStartPosition, descriptor.fileName());

                readSection(syncSegment.input, syncSegment.endPosition, descriptor);

                // Track the position at end of previous section after successfully reading mutations,
                // so we can update highwater mark after reading
                position = (int) reader.getFilePointer();

                if (!statusTracker.shouldContinue())
                {
                    break;
                }
            }
        }
        // Unfortunately CommitLogSegmentReader.SegmentIterator (for-loop) cannot throw a checked exception,
        // so we check to see if a RuntimeException is wrapping an IOException
        catch (RuntimeException exception)
        {
            if (exception.getCause() instanceof IOException)
            {
                throw (IOException) exception.getCause();
            }
            throw exception;
        }
        logger.info("Finished reading commit log", "updates", updates.size(),
                                                 "timeNanos", System.nanoTime() - startTimeNanos);
    }