Method execute

src/commands/CmdHistory.cpp:286–334

////////////////////////////////////////////////////////////////////////////////
template <class HistoryStrategy>
int CmdHistoryBase<HistoryStrategy>::execute(std::string& output) {
  rc = 0;

  // TODO is this necessary?
  groups.clear();
  addedGroup.clear();
  deletedGroup.clear();
  completedGroup.clear();

  // Apply filter.
  Filter filter;
  std::vector<Task> filtered;
  filter.subset(filtered);

  for (auto& task : filtered) {
    Datetime entry(task.get_date("entry"));

    Datetime end;
    if (task.has("end")) end = Datetime(task.get_date("end"));

    auto epoch = HistoryStrategy::getRelevantDate(entry).toEpoch();
    groups[epoch] = 0;

    // Every task has an entry date, but exclude templates.
    if (task.getStatus() != Task::recurring) ++addedGroup[epoch];

    // All deleted tasks have an end date.
    if (task.getStatus() == Task::deleted) {
      epoch = HistoryStrategy::getRelevantDate(end).toEpoch();
      groups[epoch] = 0;
      ++deletedGroup[epoch];
    }

    // All completed tasks have an end date.
    else if (task.getStatus() == Task::completed) {
      epoch = HistoryStrategy::getRelevantDate(end).toEpoch();
      groups[epoch] = 0;
      ++completedGroup[epoch];
    }
  }

  // Now build the view.
  if (HistoryStrategy::graphical)
    this->outputGraphical(output);
  else
    this->outputTabular(output);

  return rc;
}

////////////////////////////////////////////////////////////////////////////i
class MonthlyGHistoryStrategy {