Method ApplyDiff

libs/storage/storage.cpp:1705–1771

*/

void Storage::ApplyDiff(CountryId const & countryId, function<void(bool isSuccess)> const & fn)
{
  LOG(LINFO, ("Applying diff for", countryId));

  if (IsDiffApplyingInProgressToCountry(countryId))
    return;

  auto const diffLocalFile = PreparePlaceForCountryFiles(m_currentVersion, m_dataDir, GetCountryFile(countryId));
  uint64_t version;
  if (!diffLocalFile || !m_diffsDataSource->VersionFor(countryId, version))
  {
    fn(false);
    return;
  }

  auto const emplaceResult = m_diffsBeingApplied.emplace(countryId, std::make_unique<base::Cancellable>());
  CHECK_EQUAL(emplaceResult.second, true, ());

  NotifyStatusChangedForHierarchy(countryId);

  diffs::ApplyDiffParams params;
  params.m_diffFile = diffLocalFile;
  params.m_diffReadyPath = GetFileDownloadPath(countryId, MapFileType::Diff);
  params.m_oldMwmFile = GetLocalFile(countryId, version);

  LocalFilePtr & diffFile = params.m_diffFile;
  diffs::ApplyDiff(std::move(params), *emplaceResult.first->second,
                   [this, fn, countryId, diffFile](DiffApplicationResult result)
  {
    CHECK_THREAD_CHECKER(m_threadChecker, ());
    if (result == DiffApplicationResult::Ok && m_integrityValidationEnabled && !diffFile->ValidateIntegrity())
    {
      GetPlatform().RunTask(Platform::Thread::File,
                            [path = diffFile->GetPath(MapFileType::Map)] { base::DeleteFileX(path); });
      result = DiffApplicationResult::Failed;
    }

    if (m_diffsBeingApplied[countryId]->IsCancelled() && result == DiffApplicationResult::Ok)
      result = DiffApplicationResult::Cancelled;

    LOG(LINFO, ("Diff application result for", countryId, ":", result));

    m_diffsBeingApplied.erase(countryId);
    switch (result)
    {
    case DiffApplicationResult::Ok:
    {
      RegisterCountryFiles(diffFile);
      m_diffsDataSource->MarkAsApplied(countryId);
      fn(true);
      break;
    }
    case DiffApplicationResult::Cancelled:
    {
      break;
    }
    case DiffApplicationResult::Failed:
    {