/*
 * Exception
 *  Handles odd errors in Steel programs
 *
 * 1.00 (24 September 1993)
 *
 * © 1993-1998 Straylight
 */

/*----- Licensing note ----------------------------------------------------*
 *
 * This file is part of Straylight's Steel library.
 *
 * Steel 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, or (at your option)
 * any later version.
 *
 * Steel 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 Steel.  If not, write to the Free Software Foundation,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include "msgs.h"
#include "exception.h"
#include "wimpt.h"
#include "werr.h"
#include "visdelay.h"

#ifndef BOOL
#define BOOL int
#define TRUE 1
#define FALSE 0
#endif

static BOOL exception__handled;
static int *exception__handler;

/*
 * int exception_registerHandler(exception_handler env)
 *
 * Use
 *  Registers the current point as being a sensible place to go after an
 *  exception.  This is implemented as a macro for the simple reason that
 *  things tend to go a tad wrong if you define your exception_handlers in a
 *  function and then return.
 *
 * Parameters
 *  exception_handler env == an undefined variable of the type
 *    exception_handler.
 */

#ifndef exception_registerHandler
#define exception_registerHandler(env) \
  (exception__registerHandler((env),setjmp(env)))
#endif

/*
 * void exception_generate(char *message,...)
 *
 * Use
 *  Generates a Steel exception, to be handled in an appropriate manner.
 *
 * Parameters
 *  char *message == printf()-type format string
 */

void exception_generate(char *message,...)
{
  char buffer[256];
  va_list ap;
  va_start(ap,message);
  vsprintf(buffer,message,ap);
  va_end(ap);
  visdelay_suspend(); /* It doesn't mind if we suspend indefinitely */
  if (exception__handled==FALSE)
  {
    werr(FALSE,msgs_lookup("excFATAL:Fatal internal error: '%s'"),buffer);
    exit(1);
  }
  else
  {
    if (werr_error((wimpt_options() & wimpt_ONOBACKTRACE) ? 2 : 3,
                   msgs_lookup("excSEV:Internal error: '%s'.  Click OK "
                               "to continue, or Cancel to quit %s."),
                   buffer,
                   wimpt_programname())==0)
    {
      if (werr_error(2,
                     msgs_lookup("excAYS:Are you sure you want to quit %s?  "
                                 "Click OK to continue, or Cancel to quit."),
                     wimpt_programname())==0)
      {
        exit(1);
      }
      else
        longjmp(exception__handler,1);
    }
    else
      longjmp(exception__handler,1);
  }
}

/*
 * int exception__registerHandler(jmp_buf handler)
 *
 * Use
 *  This routine is for the use of exception segment only, and should not be
 *  called from your code.
 */

int exception__registerHandler(jmp_buf handler,int result)
{
  if (result==0)
  {
    exception__handled=TRUE;
    exception__handler=handler;
  }
  return (result);
}