common/error.cpp

/*
  Error  -  Lumiera Exception Interface
 
  Copyright (C)         Lumiera.org
    2008,               Hermann Vosseler <Ichthyostega@web.de>
 
  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of the
  License, or (at your option) any later version.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
* *****************************************************/



#include "common/error.hpp"
#include "common/util.hpp"

#include <exception>
#include <typeinfo>
#include <iostream>

using util::isnil;
using std::exception;


namespace lumiera
  {

  namespace error
    {
    
    inline const string default_usermsg (Error* exception_obj)  throw() 
    {
      return string("Sorry, Lumiera encountered an internal error. (")
           + typeid(*exception_obj).name() + ")";
    }
    
    
    /* constants to be used as error IDs */
    LUMIERA_ERROR_DEFINE (LOGIC    , "internal logic broken");   
    LUMIERA_ERROR_DEFINE (FATAL    , "floundered");      
    LUMIERA_ERROR_DEFINE (CONFIG   , "misconfiguration"); 
    LUMIERA_ERROR_DEFINE (STATE    , "unforseen state"); 
    LUMIERA_ERROR_DEFINE (INVALID  , "invalid input or parameters"); 
    LUMIERA_ERROR_DEFINE (EXTERNAL , "failure in external service"); 
    LUMIERA_ERROR_DEFINE (ASSERTION, "assertion failure");

  } // namespace error
  
  LUMIERA_ERROR_DEFINE (EXCEPTION, "generic Lumiera exception"); 
  
  
  
  
  Error::Error (string description, const char* id) throw()
    : std::exception (),
      id_ (id),
      msg_ (error::default_usermsg (this)),
      desc_ (description),
      cause_ ("")
  {
    lumiera_error_set (this->id_);
  }
  
  
  Error::Error (std::exception& cause, 
                string description, const char* id) throw()
    : std::exception (),
      id_ (id),
      msg_ (error::default_usermsg (this)),
      desc_ (description),
      cause_ (extractCauseMsg(cause))
  {
    lumiera_error_set (this->id_);
  }
  
  
  Error::Error (const Error& ref) throw()
    : std::exception (),
      id_ (ref.id_),
      msg_ (ref.msg_),
      desc_ (ref.desc_),
      cause_ (extractCauseMsg(ref))
  { }


  
  const char*
  Error::what() const  throw()
  {
    if (isnil (this->what_))
      {
        what_ = string(id_);
        if (!isnil (desc_))  what_ += " ("+desc_+").";
        if (!isnil (cause_)) what_ += string(" -- caused by: ") + cause_;
      }
    return what_.c_str(); 
  }
  

  const string
  Error::extractCauseMsg (const exception& cause)  throw()
  {
    const Error* err=dynamic_cast<const Error*> (&cause);
    if (err)
      {
        if (isnil (err->cause_))
          return cause.what(); // cause is root cause
        else
          return err->cause_; // cause was caused by another exception
      }
    
    // unknown other exception type
    return cause.what ();
  }

  
/* -- originally, I wanted to chain the exception objects themselfs.
      but this doesn't work; we'd need to clone the "cause" error object,
      because it can be destroyed when leaving the original
      handler by throwing a new exception.
      Anyways, not needed at the moment; maybe later? 8/2007  
  
  const exception&
  Error::rootCause () const throw()
    {
      const exception * root(this);
      if (this->cause)
        if (Error* err = dynamic_cast<Error*> (this->cause))
          root = &err->rootCause ();
        else
          root = this->cause;
      
      ENSURE (root);
      ENSURE (root!=this || !cause); 
      return *root;
    }
*/  
  
  
  
  
  
  namespace error
  {
    
    void lumiera_unexpectedException ()  throw()
    {
      const char* is_halted 
        = "### Lumiera halted due to an unexpected Error ###";
      
      std::cerr << "\n" << is_halted << "\n\n";
      ERROR (NOBUG_ON, "%s", is_halted);
      
      if (const char * errorstate = lumiera_error ())
        ERROR (NOBUG_ON, "last registered error was....\n%s", errorstate);
      
      std::terminate();
    }

    void assertion_terminate (const string& location)
    {
      throw Fatal (location, LUMIERA_ERROR_ASSERTION)
                 .setUsermsg("Program terminated because of violating "
                             "an internal consistency check.");    
    }
    
    
    void install_unexpectedException_handler ()
    {
      std::set_unexpected (lumiera_unexpectedException);      
    }
    
  } // namespace error
  
} // namespace lumiera

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