/*
 * Option conflict management routines for CUPS.
 *
 * Copyright 2007-2018 by Apple Inc.
 * Copyright 1997-2007 by Easy Software Products, all rights reserved.
 *
 * Licensed under Apache License v2.0.  See the file "LICENSE" for more
 * information.
 *
 * PostScript is a trademark of Adobe Systems, Inc.
 */

/*
 * Include necessary headers...
 */

#include "cups-private.h"
#include "ppd-private.h"


/*
 * Local constants...
 */

enum
{
  _PPD_OPTION_CONSTRAINTS,
  _PPD_INSTALLABLE_CONSTRAINTS,
  _PPD_ALL_CONSTRAINTS
};


/*
 * Local functions...
 */

static int		ppd_is_installable(ppd_group_t *installable,
			                   const char *option);
static void		ppd_load_constraints(ppd_file_t *ppd);
static cups_array_t	*ppd_test_constraints(ppd_file_t *ppd,
			                      const char *option,
					      const char *choice,
			                      int num_options,
			                      cups_option_t *options,
					      int which);


/*
 * 'cupsGetConflicts()' - Get a list of conflicting options in a marked PPD.
 *
 * This function gets a list of options that would conflict if "option" and
 * "choice" were marked in the PPD.  You would typically call this function
 * after marking the currently selected options in the PPD in order to
 * determine whether a new option selection would cause a conflict.
 *
 * The number of conflicting options are returned with "options" pointing to
 * the conflicting options.  The returned option array must be freed using
 * @link cupsFreeOptions@.
 *
 * @since CUPS 1.4/macOS 10.6@
 */

int					/* O - Number of conflicting options */
cupsGetConflicts(
    ppd_file_t    *ppd,			/* I - PPD file */
    const char    *option,		/* I - Option to test */
    const char    *choice,		/* I - Choice to test */
    cups_option_t **options)		/* O - Conflicting options */
{
  int			i,		/* Looping var */
			num_options;	/* Number of conflicting options */
  cups_array_t		*active;	/* Active conflicts */
  _ppd_cups_uiconsts_t	*c;		/* Current constraints */
  _ppd_cups_uiconst_t	*cptr;		/* Current constraint */
  ppd_choice_t		*marked;	/* Marked choice */


 /*
  * Range check input...
  */

  if (options)
    *options = NULL;

  if (!ppd || !option || !choice || !options)
    return (0);

 /*
  * Test for conflicts...
  */

  active = ppd_test_constraints(ppd, option, choice, 0, NULL,
                                _PPD_ALL_CONSTRAINTS);

 /*
  * Loop through all of the UI constraints and add any options that conflict...
  */

  for (num_options = 0, c = (_ppd_cups_uiconsts_t *)cupsArrayFirst(active);
       c;
       c = (_ppd_cups_uiconsts_t *)cupsArrayNext(active))
  {
    for (i = c->num_constraints, cptr = c->constraints;
         i > 0;
	 i --, cptr ++)
      if (_cups_strcasecmp(cptr->option->keyword, option))
      {
        if (cptr->choice)
	  num_options = cupsAddOption(cptr->option->keyword,
	                              cptr->choice->choice, num_options,
				      options);
        else if ((marked = ppdFindMarkedChoice(ppd,
	                                       cptr->option->keyword)) != NULL)
	  num_options = cupsAddOption(cptr->option->keyword, marked->choice,
				      num_options, options);
      }
  }

  cupsArrayDelete(active);

  return (num_options);
}


/*
 * 'cupsResolveConflicts()' - Resolve conflicts in a marked PPD.
 *
 * This function attempts to resolve any conflicts in a marked PPD, returning
 * a list of option changes that are required to resolve them.  On input,
 * "num_options" and "options" contain any pending option changes that have
 * not yet been marked, while "option" and "choice" contain the most recent
 * selection which may or may not be in "num_options" or "options".
 *
 * On successful return, "num_options" and "options" are updated to contain
 * "option" and "choice" along with any changes required to resolve conflicts
 * specified in the PPD file and 1 is returned.
 *
 * If option conflicts cannot be resolved, "num_options" and "options" are not
 * changed and 0 is returned.
 *
 * When resolving conflicts, @code cupsResolveConflicts@ does not consider
 * changes to the current page size (@code media@, @code PageSize@, and
 * @code PageRegion@) or to the most recent option specified in "option".
 * Thus, if the only way to resolve a conflict is to change the page size
 * or the option the user most recently changed, @code cupsResolveConflicts@
 * will return 0 to indicate it was unable to resolve the conflicts.
 *
 * The @code cupsResolveConflicts@ function uses one of two sources of option
 * constraint information.  The preferred constraint information is defined by
 * @code cupsUIConstraints@ and @code cupsUIResolver@ attributes - in this
 * case, the PPD file provides constraint resolution actions.
 *
 * The backup constraint information is defined by the
 * @code UIConstraints@ and @code NonUIConstraints@ attributes.  These
 * constraints are resolved algorithmically by first selecting the default
 * choice for the conflicting option, then iterating over all possible choices
 * until a non-conflicting option choice is found.
 *
 * @since CUPS 1.4/macOS 10.6@
 */

int					/* O  - 1 on success, 0 on failure */
cupsResolveConflicts(
    ppd_file_t    *ppd,			/* I  - PPD file */
    const char    *option,		/* I  - Newly selected option or @code NULL@ for none */
    const char    *choice,		/* I  - Newly selected choice or @code NULL@ for none */
    int           *num_options,		/* IO - Number of additional selected options */
    cups_option_t **options)		/* IO - Additional selected options */
{
  int			i,		/* Looping var */
			tries,		/* Number of tries */
			num_newopts;	/* Number of new options */
  cups_option_t		*newopts;	/* New options */
  cups_array_t		*active = NULL,	/* Active constraints */
			*pass,		/* Resolvers for this pass */
			*resolvers,	/* Resolvers we have used */
			*test;		/* Test array for conflicts */
  _ppd_cups_uiconsts_t	*consts;	/* Current constraints */
  _ppd_cups_uiconst_t	*constptr;	/* Current constraint */
  ppd_attr_t		*resolver;	/* Current resolver */
  const char		*resval;	/* Pointer into resolver value */
  char			resoption[PPD_MAX_NAME],
					/* Current resolver option */
			reschoice[PPD_MAX_NAME],
					/* Current resolver choice */
			*resptr,	/* Pointer into option/choice */
			firstpage[255];	/* AP_FIRSTPAGE_Keyword string */
  const char		*value;		/* Selected option value */
  int			changed;	/* Did we change anything? */
  ppd_choice_t		*marked;	/* Marked choice */


 /*
  * Range check input...
  */

  if (!ppd || !num_options || !options || (option == NULL) != (choice == NULL))
    return (0);

 /*
  * Build a shadow option array...
  */

  num_newopts = 0;
  newopts     = NULL;

  for (i = 0; i < *num_options; i ++)
    num_newopts = cupsAddOption((*options)[i].name, (*options)[i].value,
                                num_newopts, &newopts);
  if (option && _cups_strcasecmp(option, "Collate"))
    num_newopts = cupsAddOption(option, choice, num_newopts, &newopts);

 /*
  * Loop until we have no conflicts...
  */

  cupsArraySave(ppd->sorted_attrs);

  resolvers = NULL;
  pass      = cupsArrayNew((cups_array_func_t)_cups_strcasecmp, NULL);
  tries     = 0;

  while (tries < 100 &&
         (active = ppd_test_constraints(ppd, NULL, NULL, num_newopts, newopts,
                                        _PPD_ALL_CONSTRAINTS)) != NULL)
  {
    tries ++;

    if (!resolvers)
      resolvers = cupsArrayNew((cups_array_func_t)_cups_strcasecmp, NULL);

    for (consts = (_ppd_cups_uiconsts_t *)cupsArrayFirst(active), changed = 0;
         consts;
	 consts = (_ppd_cups_uiconsts_t *)cupsArrayNext(active))
    {
      if (consts->resolver[0])
      {
       /*
        * Look up the resolver...
	*/

        if (cupsArrayFind(pass, consts->resolver))
	  continue;			/* Already applied this resolver... */

        if (cupsArrayFind(resolvers, consts->resolver))
	{
	 /*
	  * Resolver loop!
	  */

	  DEBUG_printf(("1cupsResolveConflicts: Resolver loop with %s!",
	                consts->resolver));
          goto error;
	}

        if ((resolver = ppdFindAttr(ppd, "cupsUIResolver",
	                            consts->resolver)) == NULL)
        {
	  DEBUG_printf(("1cupsResolveConflicts: Resolver %s not found!",
	                consts->resolver));
	  goto error;
	}

        if (!resolver->value)
	{
	  DEBUG_printf(("1cupsResolveConflicts: Resolver %s has no value!",
	                consts->resolver));
	  goto error;
	}

       /*
        * Add the options from the resolver...
	*/

        cupsArrayAdd(pass, consts->resolver);
	cupsArrayAdd(resolvers, consts->resolver);

        for (resval = resolver->value; *resval && !changed;)
	{
	  while (_cups_isspace(*resval))
	    resval ++;

	  if (*resval != '*')
	    break;

	  for (resval ++, resptr = resoption;
	       *resval && !_cups_isspace(*resval);
	       resval ++)
            if (resptr < (resoption + sizeof(resoption) - 1))
	      *resptr++ = *resval;

          *resptr = '\0';

	  while (_cups_isspace(*resval))
	    resval ++;

	  for (resptr = reschoice;
	       *resval && !_cups_isspace(*resval);
	       resval ++)
            if (resptr < (reschoice + sizeof(reschoice) - 1))
	      *resptr++ = *resval;

          *resptr = '\0';

          if (!resoption[0] || !reschoice[0])
	    break;

         /*
	  * Is this the option we are changing?
	  */

          snprintf(firstpage, sizeof(firstpage), "AP_FIRSTPAGE_%s", resoption);

	  if (option &&
	      (!_cups_strcasecmp(resoption, option) ||
	       !_cups_strcasecmp(firstpage, option) ||
	       (!_cups_strcasecmp(option, "PageSize") &&
		!_cups_strcasecmp(resoption, "PageRegion")) ||
	       (!_cups_strcasecmp(option, "AP_FIRSTPAGE_PageSize") &&
		!_cups_strcasecmp(resoption, "PageSize")) ||
	       (!_cups_strcasecmp(option, "AP_FIRSTPAGE_PageSize") &&
		!_cups_strcasecmp(resoption, "PageRegion")) ||
	       (!_cups_strcasecmp(option, "PageRegion") &&
	        !_cups_strcasecmp(resoption, "PageSize")) ||
	       (!_cups_strcasecmp(option, "AP_FIRSTPAGE_PageRegion") &&
	        !_cups_strcasecmp(resoption, "PageSize")) ||
	       (!_cups_strcasecmp(option, "AP_FIRSTPAGE_PageRegion") &&
	        !_cups_strcasecmp(resoption, "PageRegion"))))
	    continue;

	 /*
	  * Try this choice...
	  */

          if ((test = ppd_test_constraints(ppd, resoption, reschoice,
					   num_newopts, newopts,
					   _PPD_ALL_CONSTRAINTS)) == NULL)
	  {
	   /*
	    * That worked...
	    */

            changed = 1;
	  }
	  else
            cupsArrayDelete(test);

	 /*
	  * Add the option/choice from the resolver regardless of whether it
	  * worked; this makes sure that we can cascade several changes to
	  * make things resolve...
	  */

	  num_newopts = cupsAddOption(resoption, reschoice, num_newopts,
				      &newopts);
        }
      }
      else
      {
       /*
        * Try resolving by choosing the default values for non-installable
	* options, then by iterating through the possible choices...
	*/

        int		j;		/* Looping var */
	ppd_choice_t	*cptr;		/* Current choice */
        ppd_size_t	*size;		/* Current page size */


        for (i = consts->num_constraints, constptr = consts->constraints;
	     i > 0 && !changed;
	     i --, constptr ++)
	{
	 /*
	  * Can't resolve by changing an installable option...
	  */

	  if (constptr->installable)
	    continue;

         /*
	  * Is this the option we are changing?
	  */

	  if (option &&
	      (!_cups_strcasecmp(constptr->option->keyword, option) ||
	       (!_cups_strcasecmp(option, "PageSize") &&
		!_cups_strcasecmp(constptr->option->keyword, "PageRegion")) ||
	       (!_cups_strcasecmp(option, "PageRegion") &&
		!_cups_strcasecmp(constptr->option->keyword, "PageSize"))))
	    continue;

         /*
	  * Get the current option choice...
	  */

          if ((value = cupsGetOption(constptr->option->keyword, num_newopts,
	                             newopts)) == NULL)
          {
	    if (!_cups_strcasecmp(constptr->option->keyword, "PageSize") ||
	        !_cups_strcasecmp(constptr->option->keyword, "PageRegion"))
	    {
	      if ((value = cupsGetOption("PageSize", num_newopts,
	                                 newopts)) == NULL)
                value = cupsGetOption("PageRegion", num_newopts, newopts);

              if (!value)
	      {
	        if ((size = ppdPageSize(ppd, NULL)) != NULL)
		  value = size->name;
		else
		  value = "";
	      }
	    }
	    else
	    {
	      marked = ppdFindMarkedChoice(ppd, constptr->option->keyword);
	      value  = marked ? marked->choice : "";
	    }
	  }

	  if (!_cups_strncasecmp(value, "Custom.", 7))
	    value = "Custom";

         /*
	  * Try the default choice...
	  */

          test = NULL;

          if (_cups_strcasecmp(value, constptr->option->defchoice) &&
	      (test = ppd_test_constraints(ppd, constptr->option->keyword,
	                                   constptr->option->defchoice,
					   num_newopts, newopts,
					   _PPD_OPTION_CONSTRAINTS)) == NULL)
	  {
	   /*
	    * That worked...
	    */

	    num_newopts = cupsAddOption(constptr->option->keyword,
	                                constptr->option->defchoice,
					num_newopts, &newopts);
            changed     = 1;
	  }
	  else
	  {
	   /*
	    * Try each choice instead...
	    */

            for (j = constptr->option->num_choices,
	             cptr = constptr->option->choices;
		 j > 0;
		 j --, cptr ++)
            {
	      cupsArrayDelete(test);
	      test = NULL;

	      if (_cups_strcasecmp(value, cptr->choice) &&
	          _cups_strcasecmp(constptr->option->defchoice, cptr->choice) &&
		  _cups_strcasecmp("Custom", cptr->choice) &&
	          (test = ppd_test_constraints(ppd, constptr->option->keyword,
	                                       cptr->choice, num_newopts,
					       newopts,
					       _PPD_OPTION_CONSTRAINTS)) == NULL)
	      {
	       /*
		* This choice works...
		*/

		num_newopts = cupsAddOption(constptr->option->keyword,
					    cptr->choice, num_newopts,
					    &newopts);
		changed     = 1;
		break;
	      }
	    }

	    cupsArrayDelete(test);
          }
        }
      }
    }

    if (!changed)
    {
      DEBUG_puts("1cupsResolveConflicts: Unable to automatically resolve "
		 "constraint!");
      goto error;
    }

    cupsArrayClear(pass);
    cupsArrayDelete(active);
    active = NULL;
  }

  if (tries >= 100)
    goto error;

 /*
  * Free the caller's option array...
  */

  cupsFreeOptions(*num_options, *options);

 /*
  * If Collate is the option we are testing, add it here.  Otherwise, remove
  * any Collate option from the resolve list since the filters automatically
  * handle manual collation...
  */

  if (option && !_cups_strcasecmp(option, "Collate"))
    num_newopts = cupsAddOption(option, choice, num_newopts, &newopts);
  else
    num_newopts = cupsRemoveOption("Collate", num_newopts, &newopts);

 /*
  * Return the new list of options to the caller...
  */

  *num_options = num_newopts;
  *options     = newopts;

  cupsArrayDelete(pass);
  cupsArrayDelete(resolvers);

  cupsArrayRestore(ppd->sorted_attrs);

  DEBUG_printf(("1cupsResolveConflicts: Returning %d options:", num_newopts));
#ifdef DEBUG
  for (i = 0; i < num_newopts; i ++)
    DEBUG_printf(("1cupsResolveConflicts: options[%d]: %s=%s", i,
                  newopts[i].name, newopts[i].value));
#endif /* DEBUG */

  return (1);

 /*
  * If we get here, we failed to resolve...
  */

  error:

  cupsFreeOptions(num_newopts, newopts);

  cupsArrayDelete(active);
  cupsArrayDelete(pass);
  cupsArrayDelete(resolvers);

  cupsArrayRestore(ppd->sorted_attrs);

  DEBUG_puts("1cupsResolveConflicts: Unable to resolve conflicts!");

  return (0);
}


/*
 * 'ppdConflicts()' - Check to see if there are any conflicts among the
 *                    marked option choices.
 *
 * The returned value is the same as returned by @link ppdMarkOption@.
 */

int					/* O - Number of conflicts found */
ppdConflicts(ppd_file_t *ppd)		/* I - PPD to check */
{
  int			i,		/* Looping variable */
			conflicts;	/* Number of conflicts */
  cups_array_t		*active;	/* Active conflicts */
  _ppd_cups_uiconsts_t	*c;		/* Current constraints */
  _ppd_cups_uiconst_t	*cptr;		/* Current constraint */
  ppd_option_t	*o;			/* Current option */


  if (!ppd)
    return (0);

 /*
  * Clear all conflicts...
  */

  cupsArraySave(ppd->options);

  for (o = ppdFirstOption(ppd); o; o = ppdNextOption(ppd))
    o->conflicted = 0;

  cupsArrayRestore(ppd->options);

 /*
  * Test for conflicts...
  */

  active    = ppd_test_constraints(ppd, NULL, NULL, 0, NULL,
                                   _PPD_ALL_CONSTRAINTS);
  conflicts = cupsArrayCount(active);

 /*
  * Loop through all of the UI constraints and flag any options
  * that conflict...
  */

  for (c = (_ppd_cups_uiconsts_t *)cupsArrayFirst(active);
       c;
       c = (_ppd_cups_uiconsts_t *)cupsArrayNext(active))
  {
    for (i = c->num_constraints, cptr = c->constraints;
         i > 0;
	 i --, cptr ++)
      cptr->option->conflicted = 1;
  }

  cupsArrayDelete(active);

 /*
  * Return the number of conflicts found...
  */

  return (conflicts);
}


/*
 * 'ppdInstallableConflict()' - Test whether an option choice conflicts with
 *                              an installable option.
 *
 * This function tests whether a particular option choice is available based
 * on constraints against options in the "InstallableOptions" group.
 *
 * @since CUPS 1.4/macOS 10.6@
 */

int					/* O - 1 if conflicting, 0 if not conflicting */
ppdInstallableConflict(
    ppd_file_t *ppd,			/* I - PPD file */
    const char *option,			/* I - Option */
    const char *choice)			/* I - Choice */
{
  cups_array_t	*active;		/* Active conflicts */


  DEBUG_printf(("2ppdInstallableConflict(ppd=%p, option=\"%s\", choice=\"%s\")",
                ppd, option, choice));

 /*
  * Range check input...
  */

  if (!ppd || !option || !choice)
    return (0);

 /*
  * Test constraints using the new option...
  */

  active = ppd_test_constraints(ppd, option, choice, 0, NULL,
				_PPD_INSTALLABLE_CONSTRAINTS);

  cupsArrayDelete(active);

  return (active != NULL);
}


/*
 * 'ppd_is_installable()' - Determine whether an option is in the
 *                          InstallableOptions group.
 */

static int				/* O - 1 if installable, 0 if normal */
ppd_is_installable(
    ppd_group_t *installable,		/* I - InstallableOptions group */
    const char  *name)			/* I - Option name */
{
  if (installable)
  {
    int			i;		/* Looping var */
    ppd_option_t	*option;	/* Current option */


    for (i = installable->num_options, option = installable->options;
         i > 0;
	 i --, option ++)
      if (!_cups_strcasecmp(option->keyword, name))
        return (1);
  }

  return (0);
}


/*
 * 'ppd_load_constraints()' - Load constraints from a PPD file.
 */

static void
ppd_load_constraints(ppd_file_t *ppd)	/* I - PPD file */
{
  int		i;			/* Looping var */
  ppd_const_t	*oldconst;		/* Current UIConstraints data */
  ppd_attr_t	*constattr;		/* Current cupsUIConstraints attribute */
  _ppd_cups_uiconsts_t	*consts;	/* Current cupsUIConstraints data */
  _ppd_cups_uiconst_t	*constptr;	/* Current constraint */
  ppd_group_t	*installable;		/* Installable options group */
  const char	*vptr;			/* Pointer into constraint value */
  char		option[PPD_MAX_NAME],	/* Option name/MainKeyword */
		choice[PPD_MAX_NAME],	/* Choice/OptionKeyword */
		*ptr;			/* Pointer into option or choice */


  DEBUG_printf(("7ppd_load_constraints(ppd=%p)", ppd));

 /*
  * Create an array to hold the constraint data...
  */

  ppd->cups_uiconstraints = cupsArrayNew(NULL, NULL);

 /*
  * Find the installable options group if it exists...
  */

  for (i = ppd->num_groups, installable = ppd->groups;
       i > 0;
       i --, installable ++)
    if (!_cups_strcasecmp(installable->name, "InstallableOptions"))
      break;

  if (i <= 0)
    installable = NULL;

 /*
  * Load old-style [Non]UIConstraints data...
  */

  for (i = ppd->num_consts, oldconst = ppd->consts; i > 0; i --, oldconst ++)
  {
   /*
    * Weed out nearby duplicates, since the PPD spec requires that you
    * define both "*Foo foo *Bar bar" and "*Bar bar *Foo foo"...
    */

    if (i > 1 &&
	!_cups_strcasecmp(oldconst[0].option1, oldconst[1].option2) &&
	!_cups_strcasecmp(oldconst[0].choice1, oldconst[1].choice2) &&
	!_cups_strcasecmp(oldconst[0].option2, oldconst[1].option1) &&
	!_cups_strcasecmp(oldconst[0].choice2, oldconst[1].choice1))
      continue;

   /*
    * Allocate memory...
    */

    if ((consts = calloc(1, sizeof(_ppd_cups_uiconsts_t))) == NULL)
    {
      DEBUG_puts("8ppd_load_constraints: Unable to allocate memory for "
		 "UIConstraints!");
      return;
    }

    if ((constptr = calloc(2, sizeof(_ppd_cups_uiconst_t))) == NULL)
    {
      free(consts);
      DEBUG_puts("8ppd_load_constraints: Unable to allocate memory for "
		 "UIConstraints!");
      return;
    }

   /*
    * Fill in the information...
    */

    consts->num_constraints = 2;
    consts->constraints     = constptr;

    if (!_cups_strncasecmp(oldconst->option1, "Custom", 6) &&
	!_cups_strcasecmp(oldconst->choice1, "True"))
    {
      constptr[0].option      = ppdFindOption(ppd, oldconst->option1 + 6);
      constptr[0].choice      = ppdFindChoice(constptr[0].option, "Custom");
      constptr[0].installable = 0;
    }
    else
    {
      constptr[0].option      = ppdFindOption(ppd, oldconst->option1);
      constptr[0].choice      = ppdFindChoice(constptr[0].option,
					      oldconst->choice1);
      constptr[0].installable = ppd_is_installable(installable,
						   oldconst->option1);
    }

    if (!constptr[0].option || (!constptr[0].choice && oldconst->choice1[0]))
    {
      DEBUG_printf(("8ppd_load_constraints: Unknown option *%s %s!",
		    oldconst->option1, oldconst->choice1));
      free(consts->constraints);
      free(consts);
      continue;
    }

    if (!_cups_strncasecmp(oldconst->option2, "Custom", 6) &&
	!_cups_strcasecmp(oldconst->choice2, "True"))
    {
      constptr[1].option      = ppdFindOption(ppd, oldconst->option2 + 6);
      constptr[1].choice      = ppdFindChoice(constptr[1].option, "Custom");
      constptr[1].installable = 0;
    }
    else
    {
      constptr[1].option      = ppdFindOption(ppd, oldconst->option2);
      constptr[1].choice      = ppdFindChoice(constptr[1].option,
					      oldconst->choice2);
      constptr[1].installable = ppd_is_installable(installable,
						   oldconst->option2);
    }

    if (!constptr[1].option || (!constptr[1].choice && oldconst->choice2[0]))
    {
      DEBUG_printf(("8ppd_load_constraints: Unknown option *%s %s!",
		    oldconst->option2, oldconst->choice2));
      free(consts->constraints);
      free(consts);
      continue;
    }

    consts->installable = constptr[0].installable || constptr[1].installable;

   /*
    * Add it to the constraints array...
    */

    cupsArrayAdd(ppd->cups_uiconstraints, consts);
  }

 /*
  * Then load new-style constraints...
  */

  for (constattr = ppdFindAttr(ppd, "cupsUIConstraints", NULL);
       constattr;
       constattr = ppdFindNextAttr(ppd, "cupsUIConstraints", NULL))
  {
    if (!constattr->value)
    {
      DEBUG_puts("8ppd_load_constraints: Bad cupsUIConstraints value!");
      continue;
    }

    for (i = 0, vptr = strchr(constattr->value, '*');
	 vptr;
	 i ++, vptr = strchr(vptr + 1, '*'));

    if (i == 0)
    {
      DEBUG_puts("8ppd_load_constraints: Bad cupsUIConstraints value!");
      continue;
    }

    if ((consts = calloc(1, sizeof(_ppd_cups_uiconsts_t))) == NULL)
    {
      DEBUG_puts("8ppd_load_constraints: Unable to allocate memory for "
		 "cupsUIConstraints!");
      return;
    }

    if ((constptr = calloc((size_t)i, sizeof(_ppd_cups_uiconst_t))) == NULL)
    {
      free(consts);
      DEBUG_puts("8ppd_load_constraints: Unable to allocate memory for "
		 "cupsUIConstraints!");
      return;
    }

    consts->num_constraints = i;
    consts->constraints     = constptr;

    strlcpy(consts->resolver, constattr->spec, sizeof(consts->resolver));

    for (i = 0, vptr = strchr(constattr->value, '*');
	 vptr;
	 i ++, vptr = strchr(vptr, '*'), constptr ++)
    {
     /*
      * Extract "*Option Choice" or just "*Option"...
      */

      for (vptr ++, ptr = option; *vptr && !_cups_isspace(*vptr); vptr ++)
	if (ptr < (option + sizeof(option) - 1))
	  *ptr++ = *vptr;

      *ptr = '\0';

      while (_cups_isspace(*vptr))
	vptr ++;

      if (*vptr == '*')
	choice[0] = '\0';
      else
      {
	for (ptr = choice; *vptr && !_cups_isspace(*vptr); vptr ++)
	  if (ptr < (choice + sizeof(choice) - 1))
	    *ptr++ = *vptr;

	*ptr = '\0';
      }

      if (!_cups_strncasecmp(option, "Custom", 6) && !_cups_strcasecmp(choice, "True"))
      {
	_cups_strcpy(option, option + 6);
	strlcpy(choice, "Custom", sizeof(choice));
      }

      constptr->option      = ppdFindOption(ppd, option);
      constptr->choice      = ppdFindChoice(constptr->option, choice);
      constptr->installable = ppd_is_installable(installable, option);
      consts->installable   |= constptr->installable;

      if (!constptr->option || (!constptr->choice && choice[0]))
      {
	DEBUG_printf(("8ppd_load_constraints: Unknown option *%s %s!",
		      option, choice));
	break;
      }
    }

    if (!vptr)
      cupsArrayAdd(ppd->cups_uiconstraints, consts);
    else
    {
      free(consts->constraints);
      free(consts);
    }
  }
}


/*
 * 'ppd_test_constraints()' - See if any constraints are active.
 */

static cups_array_t *			/* O - Array of active constraints */
ppd_test_constraints(
    ppd_file_t    *ppd,			/* I - PPD file */
    const char    *option,		/* I - Current option */
    const char    *choice,		/* I - Current choice */
    int           num_options,		/* I - Number of additional options */
    cups_option_t *options,		/* I - Additional options */
    int           which)		/* I - Which constraints to test */
{
  int			i;		/* Looping var */
  _ppd_cups_uiconsts_t	*consts;	/* Current constraints */
  _ppd_cups_uiconst_t	*constptr;	/* Current constraint */
  ppd_choice_t		key,		/* Search key */
			*marked;	/* Marked choice */
  cups_array_t		*active = NULL;	/* Active constraints */
  const char		*value,		/* Current value */
			*firstvalue;	/* AP_FIRSTPAGE_Keyword value */
  char			firstpage[255];	/* AP_FIRSTPAGE_Keyword string */


  DEBUG_printf(("7ppd_test_constraints(ppd=%p, option=\"%s\", choice=\"%s\", "
                "num_options=%d, options=%p, which=%d)", ppd, option, choice,
		num_options, options, which));

  if (!ppd->cups_uiconstraints)
    ppd_load_constraints(ppd);

  DEBUG_printf(("9ppd_test_constraints: %d constraints!",
	        cupsArrayCount(ppd->cups_uiconstraints)));

  cupsArraySave(ppd->marked);

  for (consts = (_ppd_cups_uiconsts_t *)cupsArrayFirst(ppd->cups_uiconstraints);
       consts;
       consts = (_ppd_cups_uiconsts_t *)cupsArrayNext(ppd->cups_uiconstraints))
  {
    DEBUG_printf(("9ppd_test_constraints: installable=%d, resolver=\"%s\", "
                  "num_constraints=%d option1=\"%s\", choice1=\"%s\", "
		  "option2=\"%s\", choice2=\"%s\", ...",
		  consts->installable, consts->resolver, consts->num_constraints,
		  consts->constraints[0].option->keyword,
		  consts->constraints[0].choice ?
		      consts->constraints[0].choice->choice : "",
		  consts->constraints[1].option->keyword,
		  consts->constraints[1].choice ?
		      consts->constraints[1].choice->choice : ""));

    if (consts->installable && which < _PPD_INSTALLABLE_CONSTRAINTS)
      continue;				/* Skip installable option constraint */

    if (!consts->installable && which == _PPD_INSTALLABLE_CONSTRAINTS)
      continue;				/* Skip non-installable option constraint */

    if ((which == _PPD_OPTION_CONSTRAINTS || which == _PPD_INSTALLABLE_CONSTRAINTS) && option)
    {
     /*
      * Skip constraints that do not involve the current option...
      */

      for (i = consts->num_constraints, constptr = consts->constraints;
	   i > 0;
	   i --, constptr ++)
      {
        if (!_cups_strcasecmp(constptr->option->keyword, option))
	  break;

        if (!_cups_strncasecmp(option, "AP_FIRSTPAGE_", 13) &&
	    !_cups_strcasecmp(constptr->option->keyword, option + 13))
	  break;
      }

      if (!i)
        continue;
    }

    DEBUG_puts("9ppd_test_constraints: Testing...");

    for (i = consts->num_constraints, constptr = consts->constraints;
         i > 0;
	 i --, constptr ++)
    {
      DEBUG_printf(("9ppd_test_constraints: %s=%s?", constptr->option->keyword,
		    constptr->choice ? constptr->choice->choice : ""));

      if (constptr->choice &&
          (!_cups_strcasecmp(constptr->option->keyword, "PageSize") ||
           !_cups_strcasecmp(constptr->option->keyword, "PageRegion")))
      {
       /*
        * PageSize and PageRegion are used depending on the selected input slot
	* and manual feed mode.  Validate against the selected page size instead
	* of an individual option...
	*/

        if (option && choice &&
	    (!_cups_strcasecmp(option, "PageSize") ||
	     !_cups_strcasecmp(option, "PageRegion")))
	{
	  value = choice;
        }
	else if ((value = cupsGetOption("PageSize", num_options,
	                                options)) == NULL)
	  if ((value = cupsGetOption("PageRegion", num_options,
	                             options)) == NULL)
	    if ((value = cupsGetOption("media", num_options, options)) == NULL)
	    {
	      ppd_size_t *size = ppdPageSize(ppd, NULL);

              if (size)
	        value = size->name;
	    }

        if (value && !_cups_strncasecmp(value, "Custom.", 7))
	  value = "Custom";

        if (option && choice &&
	    (!_cups_strcasecmp(option, "AP_FIRSTPAGE_PageSize") ||
	     !_cups_strcasecmp(option, "AP_FIRSTPAGE_PageRegion")))
	{
	  firstvalue = choice;
        }
	else if ((firstvalue = cupsGetOption("AP_FIRSTPAGE_PageSize",
	                                     num_options, options)) == NULL)
	  firstvalue = cupsGetOption("AP_FIRSTPAGE_PageRegion", num_options,
	                             options);

        if (firstvalue && !_cups_strncasecmp(firstvalue, "Custom.", 7))
	  firstvalue = "Custom";

        if ((!value || _cups_strcasecmp(value, constptr->choice->choice)) &&
	    (!firstvalue || _cups_strcasecmp(firstvalue, constptr->choice->choice)))
	{
	  DEBUG_puts("9ppd_test_constraints: NO");
	  break;
	}
      }
      else if (constptr->choice)
      {
       /*
        * Compare against the constrained choice...
	*/

        if (option && choice && !_cups_strcasecmp(option, constptr->option->keyword))
	{
	  if (!_cups_strncasecmp(choice, "Custom.", 7))
	    value = "Custom";
	  else
	    value = choice;
	}
        else if ((value = cupsGetOption(constptr->option->keyword, num_options,
	                                options)) != NULL)
        {
	  if (!_cups_strncasecmp(value, "Custom.", 7))
	    value = "Custom";
	}
        else if (constptr->choice->marked)
	  value = constptr->choice->choice;
	else
	  value = NULL;

       /*
        * Now check AP_FIRSTPAGE_option...
	*/

        snprintf(firstpage, sizeof(firstpage), "AP_FIRSTPAGE_%s",
	         constptr->option->keyword);

        if (option && choice && !_cups_strcasecmp(option, firstpage))
	{
	  if (!_cups_strncasecmp(choice, "Custom.", 7))
	    firstvalue = "Custom";
	  else
	    firstvalue = choice;
	}
        else if ((firstvalue = cupsGetOption(firstpage, num_options,
	                                     options)) != NULL)
        {
	  if (!_cups_strncasecmp(firstvalue, "Custom.", 7))
	    firstvalue = "Custom";
	}
	else
	  firstvalue = NULL;

        DEBUG_printf(("9ppd_test_constraints: value=%s, firstvalue=%s", value,
	              firstvalue));

        if ((!value || _cups_strcasecmp(value, constptr->choice->choice)) &&
	    (!firstvalue || _cups_strcasecmp(firstvalue, constptr->choice->choice)))
	{
	  DEBUG_puts("9ppd_test_constraints: NO");
	  break;
	}
      }
      else if (option && choice &&
               !_cups_strcasecmp(option, constptr->option->keyword))
      {
	if (!_cups_strcasecmp(choice, "None") || !_cups_strcasecmp(choice, "Off") ||
	    !_cups_strcasecmp(choice, "False"))
	{
	  DEBUG_puts("9ppd_test_constraints: NO");
	  break;
	}
      }
      else if ((value = cupsGetOption(constptr->option->keyword, num_options,
				      options)) != NULL)
      {
	if (!_cups_strcasecmp(value, "None") || !_cups_strcasecmp(value, "Off") ||
	    !_cups_strcasecmp(value, "False"))
	{
	  DEBUG_puts("9ppd_test_constraints: NO");
	  break;
	}
      }
      else
      {
	key.option = constptr->option;

	if ((marked = (ppd_choice_t *)cupsArrayFind(ppd->marked, &key))
		== NULL ||
	    (!_cups_strcasecmp(marked->choice, "None") ||
	     !_cups_strcasecmp(marked->choice, "Off") ||
	     !_cups_strcasecmp(marked->choice, "False")))
	{
	  DEBUG_puts("9ppd_test_constraints: NO");
	  break;
	}
      }
    }

    if (i <= 0)
    {
      if (!active)
        active = cupsArrayNew(NULL, NULL);

      cupsArrayAdd(active, consts);
      DEBUG_puts("9ppd_test_constraints: Added...");
    }
  }

  cupsArrayRestore(ppd->marked);

  DEBUG_printf(("8ppd_test_constraints: Found %d active constraints!",
                cupsArrayCount(active)));

  return (active);
}