func callNext(ctx context.Context, req *pb.RunQueryRequest, res *pb.RunQueryResponse, offset, limit int32) error {
if res.GetBatch().EndCursor == nil {
return errors.New("datastore: internal error: server did not return a cursor")
}
req.Query.StartCursor = res.GetBatch().GetEndCursor()
if limit >= 0 {
req.Query.Limit = proto.Int32(limit)
}
if offset != 0 {
req.Query.Offset = proto.Int32(offset)
}
res.Reset()
return call(ctx, "runQuery", req, res)
}
// toProto converts the query to a protocol buffer.
func (q *Query) toProto(req *pb.RunQueryRequest) error {
dst := pb.Query{}
if len(q.projection) != 0 && q.keysOnly {
return errors.New("datastore: query cannot both project and be keys-only")
}
dst.Reset()
if q.kind != "" {
dst.Kind = []*pb.KindExpression{&pb.KindExpression{Name: proto.String(q.kind)}}
}
if q.projection != nil {
for _, propertyName := range q.projection {
dst.Projection = append(dst.Projection, &pb.PropertyExpression{Property: &pb.PropertyReference{Name: proto.String(propertyName)}})
}
if q.distinct {
for _, propertyName := range q.projection {
dst.GroupBy = append(dst.GroupBy, &pb.PropertyReference{Name: proto.String(propertyName)})
}
}
}
if q.keysOnly {
dst.Projection = []*pb.PropertyExpression{&pb.PropertyExpression{Property: &pb.PropertyReference{Name: proto.String(keyFieldName)}}}
}
var filters []*pb.Filter
for _, qf := range q.filter {
if qf.FieldName == "" {
return errors.New("datastore: empty query filter field name")
}
v, errStr := interfaceToProto(reflect.ValueOf(qf.Value).Interface())
if errStr != "" {
return errors.New("datastore: bad query filter value type: " + errStr)
}
xf := &pb.PropertyFilter{
Operator: operatorToProto[qf.Op],
Property: &pb.PropertyReference{Name: proto.String(qf.FieldName)},
Value: v,
}
if xf.Operator == nil {
return errors.New("datastore: unknown query filter operator")
}
filters = append(filters, &pb.Filter{PropertyFilter: xf})
}
if q.ancestor != nil {
filters = append(filters, &pb.Filter{
PropertyFilter: &pb.PropertyFilter{
Property: &pb.PropertyReference{Name: proto.String("__key__")},
Operator: pb.PropertyFilter_HAS_ANCESTOR.Enum(),
Value: &pb.Value{KeyValue: keyToProto(q.ancestor)},
}})
}
if len(filters) == 1 {
dst.Filter = filters[0]
} else if len(filters) > 1 {
dst.Filter = &pb.Filter{CompositeFilter: &pb.CompositeFilter{
Operator: pb.CompositeFilter_AND.Enum(),
Filter: 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: proto.String(qo.FieldName)},
Direction: sortDirectionToProto[qo.Direction],
}
if xo.Direction == nil {
return errors.New("datastore: unknown query order direction")
}
dst.Order = append(dst.Order, xo)
}
if q.limit >= 0 {
dst.Limit = proto.Int32(q.limit)
}
if q.offset != 0 {
dst.Offset = proto.Int32(q.offset)
}
dst.StartCursor = q.start
dst.EndCursor = q.end
req.Query = &dst
return nil
}