Function format_expr_params

src/pl/plpgsql/src/pl_exec.c:8639–8689

* Return a formatted string with information about an expression's parameters, * or NULL if the expression does not take any parameters. * The result is in the eval_mcontext. */

 * The result is in the eval_mcontext.
 */
static char *
format_expr_params(PLpgSQL_execstate *estate,
				   const PLpgSQL_expr *expr)
{
	int			paramno;
	int			dno;
	StringInfoData paramstr;
	MemoryContext oldcontext;

	if (!expr->paramnos)
		return NULL;

	oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));

	initStringInfo(&paramstr);
	paramno = 0;
	dno = -1;
	while ((dno = bms_next_member(expr->paramnos, dno)) >= 0)
	{
		Datum		paramdatum;
		Oid			paramtypeid;
		bool		paramisnull;
		int32		paramtypmod;
		PLpgSQL_var *curvar;

		curvar = (PLpgSQL_var *) estate->datums[dno];

		exec_eval_datum(estate, (PLpgSQL_datum *) curvar,
						&paramtypeid, &paramtypmod,
						&paramdatum, &paramisnull);

		appendStringInfo(&paramstr, "%s%s = ",
						 paramno > 0 ? ", " : "",
						 curvar->refname);

		if (paramisnull)
			appendStringInfoString(&paramstr, "NULL");
		else
			appendStringInfoStringQuoted(&paramstr,
										 convert_value_to_string(estate,
																 paramdatum,
																 paramtypeid),
										 -1);

		paramno++;
	}

	MemoryContextSwitchTo(oldcontext);

	return paramstr.data;
}

/*
 * Return a formatted string with information about the parameter values,