bool Pair::read()

in gloo/transport/tcp/tls/pair.cc [124:194]
55 lines of code
14 McCabe index (conditional complexity)

bool Pair::read() {
  NonOwningPtr<UnboundBuffer> buf;

  for (;;) {
    struct iovec iov = {
        .iov_base = nullptr,
        .iov_len = 0,
    };
    const auto nbytes = prepareRead(rx_, buf, iov);
    if (nbytes < 0) {
      return false;
    }

    // Break from loop if the op is complete.
    // Note that this means that the buffer pointer has been
    // set, per the call to prepareRead.
    if (nbytes == 0) {
      break;
    }

    ssize_t rv = 0;
    for (;;) {
      rv = _glootls::SSL_read(ssl_, iov.iov_base, iov.iov_len);
      if (rv <= 0) {
        int err = _glootls::SSL_get_error(ssl_, rv);

        GLOO_ENFORCE(err != SSL_ERROR_NONE);
        GLOO_ENFORCE(err != SSL_ERROR_WANT_WRITE);

        if (err == SSL_ERROR_WANT_READ) {
          return false;
        }

        if (err == SSL_ERROR_ZERO_RETURN) {
          if (!sync_) {
            return false;
          }
        }

        if (err == SSL_ERROR_SYSCALL) {
          fatal_error_occurred_ = true;
          if (errno == EPIPE || errno == ECONNRESET) {
            if (!sync_) {
              return false;
            }
          }
        }

        // Unexpected error
        signalException(GLOO_ERROR_MSG(
            "SSL_read ", peer_.str(), " failed: ", "ssl error: ", err,
            ", errno = ", strerror(errno),
            ", ssl error message: ", getSSLErrorMessage()));
        return false;
      }
      break;
    }

    // Transition to CLOSED on EOF
    if (rv == 0) {
      signalException(
          GLOO_ERROR_MSG("Connection closed by peer ", peer_.str()));
      return false;
    }

    rx_.nread += rv;
  }

  readComplete(buf);
  return true;
}