// TODO(djd): This function is ugly in its current context. Refactor.
func callNext(ctx context.Context, client *Client, req *pb.RunQueryRequest, resp *pb.RunQueryResponse, offset, limit int32) (*pb.RunQueryResponse, error) {
if resp.GetBatch().EndCursor == nil {
return nil, errors.New("datastore: internal error: server did not return a cursor")
}
q := req.GetQuery()
q.StartCursor = resp.Batch.EndCursor
q.Offset = offset
if limit >= 0 {
q.Limit = &wrapperspb.Int32Value{limit}
}
return client.client.RunQuery(ctx, req)
}
// toProto converts the query to a protocol buffer.
func (q *Query) toProto(req *pb.RunQueryRequest) error {
if len(q.projection) != 0 && q.keysOnly {
return errors.New("datastore: query cannot both project and be keys-only")
}
dst := &pb.Query{}
if q.kind != "" {
dst.Kind = []*pb.KindExpression{{Name: q.kind}}
}
if q.projection != nil {
for _, propertyName := range q.projection {
dst.Projection = append(dst.Projection, &pb.Projection{Property: &pb.PropertyReference{Name: propertyName}})
}
if q.distinct {
for _, propertyName := range q.projection {
dst.DistinctOn = append(dst.DistinctOn, &pb.PropertyReference{Name: propertyName})
}
}
}
if q.keysOnly {
dst.Projection = []*pb.Projection{{Property: &pb.PropertyReference{Name: keyFieldName}}}
}
var filters []*pb.Filter
for _, qf := range q.filter {
if qf.FieldName == "" {
return errors.New("datastore: empty query filter field name")
}
v, err := interfaceToProto(reflect.ValueOf(qf.Value).Interface(), false)
if err != nil {
return fmt.Errorf("datastore: bad query filter value type: %v", err)
}
op, ok := operatorToProto[qf.Op]
if !ok {
return errors.New("datastore: unknown query filter operator")
}
xf := &pb.PropertyFilter{
Op: op,
Property: &pb.PropertyReference{Name: qf.FieldName},
Value: v,
}
filters = append(filters, &pb.Filter{
FilterType: &pb.Filter_PropertyFilter{xf},
})
}
if q.ancestor != nil {
filters = append(filters, &pb.Filter{
FilterType: &pb.Filter_PropertyFilter{&pb.PropertyFilter{
Property: &pb.PropertyReference{Name: "__key__"},
Op: pb.PropertyFilter_HAS_ANCESTOR,
Value: &pb.Value{ValueType: &pb.Value_KeyValue{keyToProto(q.ancestor)}},
}}})
}
if len(filters) == 1 {
dst.Filter = filters[0]
} else if len(filters) > 1 {
dst.Filter = &pb.Filter{FilterType: &pb.Filter_CompositeFilter{&pb.CompositeFilter{
Op: pb.CompositeFilter_AND,
Filters: filters,
}}}
}
for _, qo := range q.order {
if qo.FieldName == "" {
return errors.New("datastore: empty query order field name")
}
xo := &pb.PropertyOrder{
Property: &pb.PropertyReference{Name: qo.FieldName},
Direction: sortDirectionToProto[qo.Direction],
}
dst.Order = append(dst.Order, xo)
}
if q.limit >= 0 {
dst.Limit = &wrapperspb.Int32Value{q.limit}
}
dst.Offset = q.offset
dst.StartCursor = q.start
dst.EndCursor = q.end
if t := q.trans; t != nil {
if t.id == nil {
return errExpiredTransaction
}
if q.eventual {
return errors.New("datastore: cannot use EventualConsistency query in a transaction")
}
req.ReadOptions = &pb.ReadOptions{
ConsistencyType: &pb.ReadOptions_Transaction{t.id},
}
}
if q.eventual {
req.ReadOptions = &pb.ReadOptions{&pb.ReadOptions_ReadConsistency_{pb.ReadOptions_EVENTUAL}}
}
req.QueryType = &pb.RunQueryRequest_Query{dst}
return nil
}