source/Exception.cxx

   1 #include <source/Exception.hxx>
   2 #include <cstring> // strncpy()
   3
   4 namespace libsex {
   5
   6 Exception::Exception(const char* const message) throw()
   7 : _previous(0)
   8 {
   9         _initMessage(message);
  10 }
  11
  12 Exception::Exception(
  13         const char* const message,
  14         const Exception& previous) throw()
  15 : _previous(0)
  16 {
  17         _initMessage(message);
  18         try {
  19                 _previous = previous.clone();
  20         } catch (std::bad_alloc& e) {
  21                 // We need to know the amount of characters
  22                 // that can be put into _message.
  23
  24                 // Size to begin with:
  25                 unsigned int length = Exception::LENGTH;
  26                 // Substract characters written so far:
  27                 length -= strlen(_message);
  28                 // Substract nullbyte appended by strcat().
  29                 // Prevent underflow.
  30                 if (length > 0) --length;
  31
  32                 // Add notice to our original message:
  33                 strncat(_message, "\n"
  34                         "std::bad_alloc while cloning Exception!",
  35                         length);
  36         }
  37 }
  38
  39 Exception::~Exception() throw()
  40 {
  41         if (_previous) delete _previous;
  42 }
  43
  44 void Exception::write(std::ostream& out) const throw(std::ios_base::failure)
  45 {
  46         out << what();
  47 }
  48
  49 void Exception::backtrace(std::ostream& out) const throw(std::ios_base::failure)
  50 {
  51         write(out);
  52         if (_previous != 0) {
  53                 out << "\n";
  54                 _previous->backtrace(out);
  55         }
  56 }
  57
  58 const Exception* Exception::clone() const
  59 throw(std::bad_alloc)
  60 {
  61         if (_previous) {
  62                 return new Exception(_message, *_previous);
  63         } else {
  64                 return new Exception(_message);
  65         }
  66 }
  67
  68 const char* Exception::what() const throw()
  69 {
  70         return _message;
  71 }
  72
  73 void Exception::_initMessage(const char* const message)
  74 {
  75         strncpy(_message, message, Exception::LENGTH);
  76         // if |message| < |_message|
  77         //      strncpy() will pad with 0
  78         // else
  79         //      strncpy() will NOT add a trailing 0!
  80         _message[Exception::LENGTH] = 0;
  81 }
  82
  83 } // namespace