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

 *

 * tablesample.c

 *      Support functions for TABLESAMPLE feature

 *

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

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 *

 * IDENTIFICATION

 *      src/backend/access/tablesample/tablesample.c

 *

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

 */

#include "postgres.h"

#include "access/tsmapi.h"

/*

 * GetTsmRoutine --- get a TsmRoutine struct by invoking the handler.

 *

 * This is a convenience routine that's just meant to check for errors.

 */

TsmRoutine *

GetTsmRoutine(Oid tsmhandler)

{

  Datum   datum;

  TsmRoutine *routine;

  datum = OidFunctionCall1(tsmhandler, PointerGetDatum(NULL));

  routine = (TsmRoutine *) DatumGetPointer(datum);

  if (routine == NULL || !IsA(routine, TsmRoutine))

    elog(ERROR, "tablesample handler function %u did not return a TsmRoutine struct",

       tsmhandler);

  return routine;

}