int table_streams::init()

in src/data_query.h [104:164]

• 56 lines of code
• 29 McCabe index (conditional complexity)

int table_streams::init(int dbfd, bool is_read_only, const unsigned char *magic,
                        int record_offset, int record_size) {
  int flags = is_read_only ? O_RDONLY : (O_RDWR | O_CREAT);
  std::string index_name = name + ".index";
  int datafd = openat(dbfd, name.c_str(), flags);
  int indexfd = openat(dbfd, index_name.c_str(), flags);
  int has_error = 0;
  if (datafd == -1)
    has_error |= is_read_only ? 1 : error("could not open <dbdir>/" + name);
  if (indexfd == -1)
    has_error |=
        is_read_only ? 1 : error("could not open <dbdir>/" + index_name);
  if (has_error) {
    close(indexfd);
    close(datafd);
    return 1;
  }
  if (!is_read_only) {
    fchmod(indexfd, 0644);
    fchmod(datafd, 0644);
  }

  if (data.init(datafd, is_read_only))
    return error("could not open <dbdir>/" + name);
  if (index.init(indexfd, is_read_only))
    return error("could not open <dbdir>/" + index_name);

  // Check that file sizes make sense.
  const unsigned char index_magic[] = {'s', 2, 'm', 0x1, 'n', 0xd, 0xe, 'x'};
  assert(sizeof(index_magic) == magic_size);
  if (data.get_num_bytes_on_open()) {
    if (!index.get_num_bytes_on_open())
      return error("unexpected data without index for " + name);
    if (data.get_num_bytes_on_open() < magic_size ||
        (data.get_num_bytes_on_open() - record_offset) % record_size)
      return error("invalid data for " + name);

    unsigned char file_magic[magic_size];
    if (data.seek(0) || data.read(file_magic, magic_size) != magic_size ||
        memcmp(file_magic, magic, magic_size))
      return error("bad magic for " + name);
  } else if (!is_read_only) {
    if (data.seek(0) || data.write(magic, magic_size) != magic_size)
      return error("could not write magic for " + name);
  }
  if (index.get_num_bytes_on_open()) {
    if (!data.get_num_bytes_on_open())
      return error("unexpected index without " + name);
    if (index.get_num_bytes_on_open() < magic_size)
      return error("invalid index for " + name);

    unsigned char file_magic[magic_size];
    if (index.seek(0) || index.read(file_magic, magic_size) != magic_size ||
        memcmp(file_magic, index_magic, magic_size))
      return error("bad index magic for " + name);
  } else if (!is_read_only) {
    if (index.seek(0) || index.write(index_magic, magic_size) != magic_size)
      return error("could not write index magic for " + name);
  }
  return 0;
}