error.hh

PIXIL is a small footprint operating environment, complete with PDA PIM applications, a browser and

/********************************************************************************
  error.hh

  purpose:
    Error handling stuff: exception handling and error message display.

  notes:

  to do:

  author(s):
   - Dirk Farin, [e-mail]

  modifications:
   29/Sep/1999 - Dirk Farin
    - ShowMessage() can now be given a Excpt_Base argument. This allows
      the MessageDisplay to selectively enable/disable the display of
      some error classes.
   20/Sep/1999 - Dirk Farin
    - complete cleanup, ShowNote() removed
   03/Jan/1999 - Dirk Farin
    - ShowNote()
   28/Dec/1998 - Dirk Farin
    - new implementation based on exceptions
   15/Nov/1998 - Dirk Farin
    - first implementation

 ********************************************************************************
    Copyright (C) 1999  Dirk Farin

    This program is distributed under GNU Public License (GPL) as
    outlined in the COPYING file that comes with the source distribution.

    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 ********************************************************************************/

#ifndef DVDVIEW_ERROR_HH
#define DVDVIEW_ERROR_HH

// We need: __ASSERT_FUNCTION
#  include <assert.h>


/* Severity of a message or an exception. Not all severity levels are allowed
   in exceptions. "ErrSev_Note" must not be used in exceptions as the normal
   program flow should not be interrupted in this case.
   //"ErrSev_Empty" is a dummy value that must not be used anywhere.
*/

enum ErrorSeverity {
  //ErrSev_Empty,   // Initial state of Excpt_Base after creation. Not an error level!
  ErrSev_Note,    // Things that are worth noting but that do not have any implications for execution.
  ErrSev_Warning, // Explains why some things may not be as expected and warn about things that may go wrong.
  ErrSev_Error,   // The usual stuff like "file not found".
  ErrSev_Critical,// Several unexpected errors occurred so something is going seriously wrong.
  ErrSev_Assertion,// This should never never never go wrong. Even if the input is completely damaged.
};



/* A MessageDisplay is the place where warnings and errors go.
 */

class MessageDisplay
{
public:
  virtual ~MessageDisplay() { }

  virtual void ShowMessage(ErrorSeverity,const char* text) const = 0;
  virtual void ShowMessage(const class Excpt_Base&) const = 0;


  // Message output on the standard display.

  static void Show(ErrorSeverity,const char* text);
  static void Show(const class Excpt_Base&);
  static void SetStandardDisplay(MessageDisplay*);

private:
  static const MessageDisplay* std_msgdisplay;
};






class Excpt_Base
{
public:
  Excpt_Base(ErrorSeverity);
  Excpt_Base(ErrorSeverity,const char* text);

  const static unsigned int c_MaxTextLen = 500;

  enum ErrorSeverity m_severity;
  char               m_text[c_MaxTextLen+1];
};


class Excpt_Assertion : public Excpt_Base
{
public:
  Excpt_Assertion(const char* expr,const char* file, const char* function,int line);
};

#ifdef NDEBUG
#define Assert(expr)
#else
#if defined(__ASSERT_FUNCTION) && defined(__STRING)
#define Assert(expr) \
 (void)(expr ? 0 : (throw Excpt_Assertion(__STRING(expr),__FILE__,__ASSERT_FUNCTION,__LINE__),1) );
#else
#define Assert(expr) \
 (void)(expr ? 0 : (throw Excpt_Assertion("no string information",__FILE__,"no function information",__LINE__),1) );
#endif
#endif


class Excpt_NotImplemented : public Excpt_Base
{
public:
  Excpt_NotImplemented(const char* file, int line);
};

#define NotImplemented throw Excpt_NotImplemented(__FILE__,__LINE__);


#endif