bool ZkDeserializer::Parse()

in src/hbase/serde/zk.cc [34:76]

• 24 lines of code
• 5 McCabe index (conditional complexity)

bool ZkDeserializer::Parse(folly::IOBuf *buf, google::protobuf::Message *out) {
  // The format is like this
  // 1 byte of magic number. 255
  // 4 bytes of id length.
  // id_length number of bytes for the id of who put up the znode
  // 4 bytes of a magic string PBUF
  // Then the protobuf serialized without a varint header.

  folly::io::Cursor c{buf};

  // There should be a magic number for recoverable zk
  uint8_t magic_num = c.read<uint8_t>();
  if (magic_num != 255) {
    LOG(ERROR) << "Magic number not in ZK znode data expected 255 got =" << unsigned(magic_num);
    throw runtime_error("Magic number not in znode data");
  }
  // How long is the id?
  uint32_t id_len = c.readBE<uint32_t>();

  if (id_len >= c.length()) {
    LOG(ERROR) << "After skiping the if from zookeeper data there's not enough "
                  "left to read anything else";
    throw runtime_error("Not enough bytes to decode from zookeeper");
  }

  // Skip the id
  c.skip(id_len);

  // Make sure that the magic string is there.
  if (MAGIC_STRING != c.readFixedString(4)) {
    LOG(ERROR) << "There was no PBUF magic string.";
    throw runtime_error("No PBUF magic string in the zookpeeper data.");
  }

  // Try to decode the protobuf.
  // If there's an error bail out.
  if (out->ParseFromArray(c.data(), c.length()) == false) {
    LOG(ERROR) << "Error parsing Protobuf Message";
    throw runtime_error("Error parsing protobuf");
  }

  return true;
}