// loadDoc converts from protobufs to a struct pointer or
// FieldLoadSaver/FieldMetadataLoadSaver. The src param provides the document's
// stored fields and facets, and any document metadata. An additional slice of
// fields, exprs, may optionally be provided to contain any derived expressions
// requested by the developer.
func loadDoc(dst interface{}, src *pb.Document, exprs []*pb.Field) (err error) {
fields, err := protoToFields(src.Field)
if err != nil {
return err
}
facets, err := protoToFacets(src.Facet)
if err != nil {
return err
}
if len(exprs) > 0 {
exprFields, err := protoToFields(exprs)
if err != nil {
return err
}
// Mark each field as derived.
for i := range exprFields {
exprFields[i].Derived = true
}
fields = append(fields, exprFields...)
}
meta := &DocumentMetadata{
Rank: int(src.GetOrderId()),
Facets: facets,
}
switch x := dst.(type) {
case FieldMetadataLoadSaver:
return x.Load(fields, meta)
case FieldLoadSaver:
return x.Load(fields)
default:
return loadStructWithMeta(dst, fields, meta)
}
}
// Next returns the ID of the next result. When there are no more results,
// Done is returned as the error.
//
// dst must be a non-nil struct pointer, implement the FieldLoadSaver or
// FieldMetadataLoadSaver interface, or be a nil interface value. If a non-nil
// dst is provided, it will be filled with the indexed fields. dst is ignored
// if this iterator was created with an IDsOnly option.
func (t *Iterator) Next(dst interface{}) (string, error) {
if t.err == nil && len(t.listRes)+len(t.searchRes) == 0 && t.more != nil {
t.err = t.more(t)
}
if t.err != nil {
return "", t.err
}
var doc *pb.Document
var exprs []*pb.Field
switch {
case len(t.listRes) != 0:
doc = t.listRes[0]
t.listRes = t.listRes[1:]
case len(t.searchRes) != 0:
doc = t.searchRes[0].Document
exprs = t.searchRes[0].Expression
t.searchRes = t.searchRes[1:]
default:
return "", Done
}
if doc == nil {
return "", errors.New("search: internal error: no document returned")
}
if !t.idsOnly && dst != nil {
metadata := &DocumentMetadata{
Rank: int(doc.GetOrderId()),
}
if err := loadDoc(dst, doc.Field, exprs, metadata); err != nil {
return "", err
}
}
if t.limit > 0 {
t.limit--
if t.limit == 0 {
t.more = nil // prevent further fetches
}
}
return doc.GetId(), nil
}