/********************************************************************\

  Name:         mexception.hxx
  Created by:   Stefan Ritt

  Contents:     Midas exception with stack trace

\********************************************************************/

#ifndef _MEXCEPT_HXX
#define _MEXCEPT_HXX

#include <string>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include <execinfo.h>
#include <dlfcn.h>
#include <cxxabi.h>

/*------------------------------------------------------------------*/

// throw exception with full stack trace
#define mthrow(arg) (throw mexception(arg, true, __FILE__, __LINE__))

// throw exception with line number and file name
#define mthrow1(arg) (throw mexception(arg, false, __FILE__, __LINE__))

class mexception : public std::runtime_error  {
   std::string msg;
public:
   mexception(const std::string &arg, bool stack_trace, const char *file, int line) :
           std::runtime_error(arg) {
      std::stringstream trace_buf;
      trace_buf << "\n" << file << ":" << line << ": " << arg << std::endl;

      if (stack_trace) {
         // create strack trace and add it to message
         trace_buf << "Stack trace:" << std::endl;
         void *callstack[128];
         char buf[1024];
         int n = backtrace(callstack, sizeof(callstack) / sizeof(callstack[0]));
         char **symbols = backtrace_symbols(callstack, n);
         for (int i = 1; i < n; i++) {
            Dl_info info;
            if (dladdr(callstack[i], &info)) {
               char *demangled = nullptr;
               int status = 0;
               demangled = abi::__cxa_demangle(info.dli_sname, nullptr, 0, &status);
               snprintf(buf, sizeof(buf), "%-3d 0x%018lX %s + %zd\n",
                        i, (long unsigned int) callstack[i],
                        status == 0 ? demangled : info.dli_sname,
                        (char *) callstack[i] - (char *) info.dli_saddr);
               free(demangled);
            } else {
               snprintf(buf, sizeof(buf), "%-3d 0x%018lX\n",
                        i, (long unsigned int) callstack[i]);
            }
            trace_buf << buf;
         }
         free(symbols);
      }

      msg = trace_buf.str();
   }

   ~mexception() throw() {}

   const char *what() const throw() {
      return msg.c_str();
   }

   friend std::ostream &operator<<(std::ostream &output, mexception &m) {
      output << m.what();
      return output;
   };

   mexception(const mexception &ex) noexcept : std::runtime_error(ex.msg),msg(ex.msg) {};
};

static_assert(std::is_nothrow_copy_constructible<mexception>::value,
              "mexception must be nothrow copy constructible");

#endif // _MEXCEPT_HXX