Exception.h

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#ifndef MUTILS_EXCEPTION_H
#define MUTILS_EXCEPTION_H

#include <exception>

#include "mutils/Log.h"

#define MU_THROW(ex, src, msg, ...) do { \
    char _mu_buf[4096]; \
    bool db = (mutils::Log::level >= mutils::Log::DEBUG); \
    mutils::cxxsnprintf(_mu_buf, sizeof(_mu_buf), "%s:%0*d: " msg "\n", \
              (db ? (src) : ""), (db ? 1 : 4), __LINE__, ## __VA_ARGS__); \
    if (mutils::Exception::errors) { \
      mutils::Log::error(_mu_buf); \
    } else { \
      (ex).message(_mu_buf); \
      throw (ex); \
    } \
  } while (0)

#define MU_RETHROW(ex, src, msg, ...) do { \
    (ex).print(); MU_THROW(ex, src, msg, ## __VA_ARGS__); \
  } while (0)

#define MU_THROW_IF(cond, ex, src, msg, ...) do { \
    if (cond) { MU_THROW(ex, src, msg, ## __VA_ARGS__); } \
  } while (0)


#define MU_THROW_ERRNO(ex, src, msg, ...) \
        MU_THROW(ex, src, msg ": %s", ## __VA_ARGS__, strerror(errno))

#define MU_THROW_ERRNO_IF(cond, ex, src, msg, ...) \
        MU_THROW_IF(cond, ex, src, msg ": %s", ## __VA_ARGS__, strerror(errno))


#define MU_EXCEPTION(src, msg, ...) do { \
    mutils::Exception _mu_ex; \
    MU_THROW(_mu_ex, src, msg, ## __VA_ARGS__); \
  } while (0)

#define MU_EXCEPTION_IF(cond, src, msg, ...) do { \
    mutils::Exception _mu_ex; \
    MU_THROW_IF(cond, _mu_ex, src, msg, ## __VA_ARGS__); \
  } while (0)

#define MU_EXCEPTION_ERRNO(src, msg, ...) do { \
    mutils::Exception _mu_ex; \
    MU_THROW_ERRNO(_mu_ex, src, msg, ## __VA_ARGS__); \
  } while (0)

#define MU_EXCEPTION_ERRNO_IF(cond, src, msg, ...) do { \
    mutils::Exception _mu_ex; \
    MU_THROW_ERRNO_IF(cond, _mu_ex, src, msg, ## __VA_ARGS__); \
  } while (0)


namespace mutils {

class Exception: public std::exception
{
public:
  Exception(int level = Log::ERROR)
        : level(level) { message("Default exception"); }

  virtual ~Exception() noexcept { }

  void message(const char *msg) {
    msg_  = Log::name(level);
    msg_ += ": ";
    msg_ += msg;
  }

  void print() const {
    if (level <= Log::level) { fputs(what(), Log::stream); }
    fflush(Log::stream);
  }

  virtual const char *what() const noexcept { return msg_.c_str(); }

  int level;

  static bool errors;

protected:
  std::string msg_;
};

inline void printException(std::exception &ex)
{
  auto mex = dynamic_cast<mutils::Exception *>(&ex);
  if (mex) { mex->print(); }
  else     { fprintf(stderr, "%s\n", ex.what()); }
}

inline void exitException(std::exception &ex, int status = EXIT_FAILURE)
{
  printException(ex);
  fprintf(stderr, "Exception caught (Log::file = %s); exiting...\n",
          Log::file.c_str());
  exit(status);
}

}  // namespace mutils

#endif  // MUTILS_EXCEPTION_H