Method sortAndPaginateUsingVar

query/query.go:2697–2738

(ctx context.Context)

}

func (sg *SubGraph) sortAndPaginateUsingVar(ctx context.Context) error {
	// nil has a different meaning from an initialized map of zero length here. If the variable
	// didn't return any values then UidToVal would be an empty with zero length. If the variable
	// was used before definition, UidToVal would be nil.
	if sg.Params.UidToVal == nil {
		return errors.Errorf("Variable: [%s] used before definition.", sg.Params.Order[0].Attr)
	}

	for i := range sg.uidMatrix {
		ul := sg.uidMatrix[i]
		uids := make([]uint64, 0, len(ul.Uids))
		values := make([][]types.Val, 0, len(ul.Uids))
		for _, uid := range ul.Uids {
			v, ok := sg.Params.UidToVal.Get(uid)
			if !ok {
				// We skip the UIDs which don't have a value
				continue
			}
			values = append(values, []types.Val{v})
			uids = append(uids, uid)
		}
		if len(values) == 0 {
			continue
		}
		if err := types.Sort(values, &uids, []bool{sg.Params.Order[0].Desc}, ""); err != nil {
			return err
		}
		sg.uidMatrix[i].Uids = uids
	}

	if sg.Params.Count != 0 || sg.Params.Offset != 0 {
		// Apply the pagination.
		for i := range sg.uidMatrix {
			start, end := x.PageRange(sg.Params.Count, sg.Params.Offset, len(sg.uidMatrix[i].Uids))
			sg.uidMatrix[i].Uids = sg.uidMatrix[i].Uids[start:end]
		}
	}

	// Update the destUids as we might have removed some UIDs.
	sg.updateDestUids()
	return nil
}

// isValidArg checks if arg passed is valid keyword.
func isValidArg(a string) bool {