Fix memory leak and minor refactoring

[pjueon]

• there was no free for the strdup in the code

  • description on strdup from cppreference: The returned pointer must be passed to free to avoid a memory leak.
  • replaced strdup with std::string (fix memory leak)

• minor refactoring

  • changed time_source type to std::unque_ptr (remove potential memory leak risk)

[pjueon]

@hzeller

[pjueon]

Thanks for the feedback.

Removing the variable service looks good to me.

The factory function that returns the raw pointer still doesn't feel right to me though. You might reuse the the factory somewhere else in the future.

You can use std::make_unique to avoid repetetive std::unique_ptr<TimeSignalSource> in the factory:

std::unique_ptr<TimeSignalSource> CreateTimeSourceFromName(const char *n) {
  if (strcasecmp(n, "DCF77") == 0)
    return std::make_unique<DCF77TimeSignalSource>();
  if (strcasecmp(n, "WWVB") == 0)
    return std::make_unique<WWVBTimeSignalSource>();
  if (strcasecmp(n, "JJY40") == 0)
    return std::make_unique<JJY40TimeSignalSource>();
  if (strcasecmp(n, "JJY60") == 0)
    return std::make_unique<JJY60TimeSignalSource>();
  if (strcasecmp(n, "MSF") == 0)
    return std::make_unique<MSFTimeSignalSource>();
  return nullptr;
}

To use std::make_unique, C++14 or higher is required. You can also implement your own version of make_unique function if you don't want to change the C++ standard requirements:

template<class T>
std::unique_ptr<T> make_unque(){
  return std::unique_ptr<T>{new T()};
}

[pjueon]

Removed std::string service. Please let me know your opinion about make_unique. @hzeller

[hzeller]

I think switching to c++14 and using make_unique sounds good to me.

[hzeller]

Thanks, merged!