Function refresh_changed_fields

src/jrd/vio.cpp:6608–6723

static void refresh_changed_fields(thread_db* tdbb, Record* old_rec, record_param* cur_rpb,
	record_param* new_rpb)
{
/**************************************
 *
 *	r e f r e s h _ c h a n g e d _ f i e l d s
 *
 **************************************
 *
 * Functional description
 *	Update new_rpb with foreign key fields values changed by cascade triggers.
 *  Consider self-referenced foreign keys only.
 *  Also, if AllowUpdateOverwrite is set to false, raise error when non
 *  self-referenced foreign key fields were changed by user triggers.
 *
 *  old_rec - old record before modify
 *  cur_rpb - just read record with possibly changed fields
 *  new_rpb - new record evaluated by modify statement and before-triggers
 *
 **************************************/
	const Database* dbb = tdbb->getDatabase();
	const auto allowOverwrite = dbb->dbb_config->getAllowUpdateOverwrite();

	jrd_rel* relation = cur_rpb->rpb_relation;

	MET_scan_partners(tdbb, relation);

	const FB_SIZE_T frgnCount = relation->rel_foreign_refs.frgn_relations ?
		relation->rel_foreign_refs.frgn_relations->count() : 0;

	RelationPages* relPages = cur_rpb->rpb_relation->getPages(tdbb);

	// Collect all fields of self-referenced foreign keys
	SortedArray<int, InlineStorage<int, 16> > fields;

	for (FB_SIZE_T i = 0; i < frgnCount; i++)
	{
		if ((*relation->rel_foreign_refs.frgn_relations)[i] == relation->rel_id)
		{
			index_desc idx;
			idx.idx_id = idx_invalid;

			if (BTR_lookup(tdbb, relation, (*relation->rel_foreign_refs.frgn_reference_ids)[i],
					&idx, relPages))
			{
				fb_assert(idx.idx_flags & idx_foreign);

				for (int fld = 0; fld < idx.idx_count; fld++)
				{
					const int fldNum = idx.idx_rpt[fld].idx_field;
					if (!fields.exist(fldNum))
						fields.add(fldNum);
				}
			}
		}
	}

	if (fields.isEmpty())