Method GpsTrackStorage

libs/map/gps_track_storage.cpp:107–165

}  // namespace

GpsTrackStorage::GpsTrackStorage(string const & filePath) : m_filePath(filePath), m_itemCount(0)
{
  auto const createNewFile = [this]
  {
    m_stream.open(m_filePath, ios::in | ios::out | ios::binary | ios::trunc);

    if (!m_stream)
      MYTHROW(OpenException, ("Open file error.", m_filePath));

    if (!WriteVersion(m_stream, kCurrentVersion))
      MYTHROW(OpenException, ("Write version error.", m_filePath));

    m_itemCount = 0;
  };

  // Open existing file
  m_stream.open(m_filePath, ios::in | ios::out | ios::binary);

  if (m_stream)
  {
    uint32_t version = 0;
    if (!ReadVersion(m_stream, version))
    {
      LOG(LWARNING, ("Recreating", m_filePath, "because can't read version from it."));
      m_stream.close();
      createNewFile();
      version = kCurrentVersion;
    }

    if (version == kCurrentVersion)
    {
      // Seek to end to get file size
      m_stream.seekp(0, ios::end);
      if (!m_stream.good())
        MYTHROW(OpenException, ("Seek to the end error.", m_filePath));

      auto const fileSize = static_cast<size_t>(m_stream.tellp());

      m_itemCount = GetItemCount(fileSize);

      // Set write position after last item position
      size_t const offset = GetItemOffset(m_itemCount);
      m_stream.seekp(offset, ios::beg);
      if (!m_stream.good())
        MYTHROW(OpenException, ("Seek to the offset error:", offset, m_filePath));

      LOG(LINFO, ("Restored", m_itemCount, "points from gps track storage"));
    }
    else
    {
      m_stream.close();
      // TODO: migration for file m_filePath from version 'version' to version 'kCurrentVersion'
      // TODO: For now we support only one version, but in future migration may be needed.
    }
  }

  if (!m_stream)
    createNewFile();