TruncationSegments truncate()

in ratis-server/src/main/java/org/apache/ratis/server/raftlog/segmented/SegmentedRaftLogCache.java [316:365]
49 lines of code
8 McCabe index (conditional complexity)

    TruncationSegments truncate(long index, LogSegment openSegment, Runnable clearOpenSegment) {
      final String reason = "truncate(" + index + ")";
      try(AutoCloseableLock writeLock = writeLock()) {
        final int segmentIndex = binarySearch(index);
        if (segmentIndex == -segments.size() - 1) {
          if (openSegment != null && openSegment.getEndIndex() >= index) {
            final long oldEnd = openSegment.getEndIndex();
            if (index == openSegment.getStartIndex()) {
              // the open segment should be deleted
              final SegmentFileInfo deleted = deleteOpenSegment(openSegment, clearOpenSegment);
              return new TruncationSegments(reason, null, Collections.singletonList(deleted));
            } else {
              openSegment.truncate(index);
              Preconditions.assertTrue(!openSegment.isOpen(),
                  () -> "Illegal state: " + openSegment + " remains open after truncate.");
              final SegmentFileInfo info = new SegmentFileInfo(openSegment.getStartIndex(),
                  oldEnd, true, openSegment.getTotalFileSize(), openSegment.getEndIndex());
              segments.add(openSegment);
              sizeInBytes += openSegment.getTotalFileSize();
              clearOpenSegment.run();
              return new TruncationSegments(reason, info, Collections.emptyList());
            }
          }
        } else if (segmentIndex >= 0) {
          final LogSegment ts = segments.get(segmentIndex);
          final long oldEnd = ts.getEndIndex();
          final List<SegmentFileInfo> list = new ArrayList<>();
          sizeInBytes -= ts.getTotalFileSize();
          ts.truncate(index);
          sizeInBytes += ts.getTotalFileSize();
          final int size = segments.size();
          for(int i = size - 1;
              i >= (ts.numOfEntries() == 0? segmentIndex: segmentIndex + 1);
              i--) {
            LogSegment s = segments.remove(i);
            sizeInBytes -= s.getTotalFileSize();
            final long endOfS = i == segmentIndex? oldEnd: s.getEndIndex();
            s.clear();
            list.add(new SegmentFileInfo(s.getStartIndex(), endOfS, false, 0, s.getEndIndex()));
          }
          if (openSegment != null) {
            list.add(deleteOpenSegment(openSegment, clearOpenSegment));
          }
          SegmentFileInfo t = ts.numOfEntries() == 0? null:
              new SegmentFileInfo(ts.getStartIndex(), oldEnd, false, ts.getTotalFileSize(), ts.getEndIndex());
          return new TruncationSegments(reason, t, list);
        }
        return null;
      }
    }