log_if.h

#include <cstdlib>
#include <exception>
#include <iostream>
#include <optional>
#include <sstream>
#include <utility>


#define LOG_IF(TEST, LEVEL) \
    if (!(TEST)) {                        \
    } else if (::_::minLevel > (LEVEL)) { \
      if ((LEVEL) == FATAL) abort();      \
    } else ::_::Log(LEVEL)

// XX cheez
#define FATAL 5

namespace _ {

int minLevel = 0;

class DtorAbort {
  // Kill the process when this goes out of scope
 public:
  inline ~DtorAbort() {
    abort();
  }
};

class Log {
 public:
  inline Log(const int level) {
    if (level == FATAL) {
      abort.emplace();
    }
  }

  inline ~Log() {
    std::cerr << ss.str() << std::endl;
  }

  template <typename T>
  inline Log& operator<<(T&& t) {
    ss << std::forward<T>(t);
    return *this;
  }

 private:
  std::ostringstream ss;
  std::optional<DtorAbort> abort;
};

}   // namespace _