/*-------------------------------------------------------------------------

 * help_config.c

 *

 * Displays available options under grand unified configuration scheme

 *

 * Options whose flag bits are set to GUC_NO_SHOW_ALL, GUC_NOT_IN_SAMPLE,

 * or GUC_DISALLOW_IN_FILE are not displayed, unless the user specifically

 * requests that variable by name

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 *

 * IDENTIFICATION

 *    src/backend/utils/misc/help_config.c

 *

 *-------------------------------------------------------------------------

 */

#include "postgres.h"

#include <limits.h>

#include <unistd.h>

#include "utils/guc_tables.h"

#include "utils/help_config.h"

/*

 * This union allows us to mix the numerous different types of structs

 * that we are organizing.

 */

typedef union

{

  struct config_generic generic;

  struct config_bool _bool;

  struct config_real real;

  struct config_int integer;

  struct config_string string;

  struct config_enum _enum;

} mixedStruct;

static void printMixedStruct(mixedStruct *structToPrint);

static bool displayStruct(mixedStruct *structToDisplay);

void

GucInfoMain(void)

{

  struct config_generic **guc_vars;

  int     numOpts,

        i;

  /* Initialize the GUC hash table */

  build_guc_variables();

  guc_vars = get_guc_variables(&numOpts);

  for (i = 0; i < numOpts; i++)

  {

    mixedStruct *var = (mixedStruct *) guc_vars[i];

    if (displayStruct(var))

      printMixedStruct(var);

  }

  exit(0);

}

/*

 * This function will return true if the struct passed to it

 * should be displayed to the user.

 */

static bool

displayStruct(mixedStruct *structToDisplay)

{

  return !(structToDisplay->generic.flags & (GUC_NO_SHOW_ALL |

                         GUC_NOT_IN_SAMPLE |

                         GUC_DISALLOW_IN_FILE));

}

/*

 * This function prints out the generic struct passed to it. It will print out

 * a different format, depending on what the user wants to see.

 */

static void

printMixedStruct(mixedStruct *structToPrint)

{

  printf("%s\t%s\t%s\t",

       structToPrint->generic.name,

       GucContext_Names[structToPrint->generic.context],

       _(config_group_names[structToPrint->generic.group]));

  switch (structToPrint->generic.vartype)

  {

    case PGC_BOOL:

      printf("BOOLEAN\t%s\t\t\t",

           (structToPrint->_bool.reset_val == 0) ?

           "FALSE" : "TRUE");

      break;

    case PGC_INT:

      printf("INTEGER\t%d\t%d\t%d\t",

           structToPrint->integer.reset_val,

           structToPrint->integer.min,

           structToPrint->integer.max);

      break;

    case PGC_REAL:

      printf("REAL\t%g\t%g\t%g\t",

           structToPrint->real.reset_val,

           structToPrint->real.min,

           structToPrint->real.max);

      break;

    case PGC_STRING:

      printf("STRING\t%s\t\t\t",

           structToPrint->string.boot_val ? structToPrint->string.boot_val : "");

      break;

    case PGC_ENUM:

      printf("ENUM\t%s\t\t\t",

           config_enum_lookup_by_value(&structToPrint->_enum,

                         structToPrint->_enum.boot_val));

      break;

    default:

      write_stderr("internal error: unrecognized run-time parameter type\n");

      break;

  }

  printf("%s\t%s\n",

       (structToPrint->generic.short_desc == NULL) ? "" : _(structToPrint->generic.short_desc),

       (structToPrint->generic.long_desc == NULL) ? "" : _(structToPrint->generic.long_desc));

}