private LogEntryProto decodeEntry()

in ratis-server/src/main/java/org/apache/ratis/server/raftlog/segmented/SegmentedRaftLogReader.java [283:333]
38 lines of code
5 McCabe index (conditional complexity)

  private LogEntryProto decodeEntry() throws IOException {
    final int max = maxOpSize.getSizeInt();
    limiter.setLimit(max);
    in.mark(max);

    byte nextByte;
    try {
      nextByte = in.readByte();
    } catch (EOFException eof) {
      // EOF at an opcode boundary is expected.
      return null;
    }
    // Each log entry starts with a var-int. Thus a valid entry's first byte
    // should not be 0. So if the terminate byte is 0, we should hit the end
    // of the segment.
    if (SegmentedRaftLogFormat.isTerminator(nextByte)) {
      verifyTerminator();
      return null;
    }

    // Here, we verify that the Op size makes sense and that the
    // data matches its checksum before attempting to construct an Op.
    int entryLength = CodedInputStream.readRawVarint32(nextByte, in);
    if (entryLength > max) {
      throw new IOException("Entry has size " + entryLength
          + ", but MAX_OP_SIZE = " + maxOpSize);
    }

    final int varintLength = CodedOutputStream.computeUInt32SizeNoTag(
        entryLength);
    final int totalLength = varintLength + entryLength;
    checkBufferSize(totalLength, max);
    in.reset();
    in.mark(max);
    IOUtils.readFully(in, temp, 0, totalLength);

    // verify checksum
    checksum.reset();
    checksum.update(temp, 0, totalLength);
    int expectedChecksum = in.readInt();
    int calculatedChecksum = (int) checksum.getValue();
    if (expectedChecksum != calculatedChecksum) {
      final String s = StringUtils.format("Log entry corrupted: Calculated checksum is %08X but read checksum is %08X.",
          calculatedChecksum, expectedChecksum);
      throw new ChecksumException(s, limiter.markPos);
    }

    // parse the buffer
    return LogEntryProto.parseFrom(
        CodedInputStream.newInstance(temp, varintLength, entryLength));
  }