/*-------------------------------------------------------------------------
 *
 * hypopg_import.c: Import of some PostgreSQL private fuctions.
 *
 * This program is open source, licensed under the PostgreSQL license.
 * For license terms, see the LICENSE file.
 *
 * Copyright (c) 2008-2018, PostgreSQL Global Development Group
 *
 *-------------------------------------------------------------------------
 */


#include "postgres.h"
#if PG_VERSION_NUM >= 90300
#include "access/htup_details.h"
#endif
#include "catalog/namespace.h"
#include "catalog/pg_opclass.h"
#include "commands/defrem.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"

#include "include/hypopg_import.h"

/*
 * Copied from src/backend/utils/adt/ruleutils.c, not exported.
 *
 * get_opclass_name			- fetch name of an index operator class
 *
 * The opclass name is appended (after a space) to buf.
 *
 * Output is suppressed if the opclass is the default for the given
 * actual_datatype.  (If you don't want this behavior, just pass
 * InvalidOid for actual_datatype.)
 */
void
get_opclass_name(Oid opclass, Oid actual_datatype,
				 StringInfo buf)
{
	HeapTuple	ht_opc;
	Form_pg_opclass opcrec;
	char	   *opcname;
	char	   *nspname;

	ht_opc = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
	if (!HeapTupleIsValid(ht_opc))
		elog(ERROR, "cache lookup failed for opclass %u", opclass);
	opcrec = (Form_pg_opclass) GETSTRUCT(ht_opc);

	if (!OidIsValid(actual_datatype) ||
		GetDefaultOpClass(actual_datatype, opcrec->opcmethod) != opclass)
	{
		/* Okay, we need the opclass name.  Do we need to qualify it? */
		opcname = NameStr(opcrec->opcname);
		if (OpclassIsVisible(opclass))
			appendStringInfo(buf, " %s", quote_identifier(opcname));
		else
		{
			nspname = get_namespace_name(opcrec->opcnamespace);
			appendStringInfo(buf, " %s.%s",
							 quote_identifier(nspname),
							 quote_identifier(opcname));
		}
	}
	ReleaseSysCache(ht_opc);
}