// Read implements part of the graphstore.Service interface.
func (s *GraphStore) Read(ctx context.Context, req *spb.ReadRequest, f graphstore.EntryFunc) error {
s.mu.RLock()
defer s.mu.RUnlock()
start := sort.Search(len(s.entries), func(i int) bool {
comp := compare.VNames(s.entries[i].Source, req.Source)
return comp != compare.LT && (comp == compare.GT || req.EdgeKind == "*" || s.entries[i].EdgeKind >= req.EdgeKind)
})
end := sort.Search(len(s.entries), func(i int) bool {
comp := compare.VNames(s.entries[i].Source, req.Source)
return comp == compare.GT || (comp != compare.LT && req.EdgeKind != "*" && s.entries[i].EdgeKind > req.EdgeKind)
})
for i := start; i < end; i++ {
if err := f(s.entries[i]); err == io.EOF {
return nil
} else if err != nil {
return err
}
}
return nil
}
// Sources returns a channel of Sources derived from a channel of entries in
// GraphStore order.
func Sources(entries <-chan *spb.Entry) <-chan *Source {
ch := make(chan *Source, 1)
go func() {
defer close(ch)
var es []*spb.Entry
for entry := range entries {
if len(es) > 0 && compare.VNames(es[0].Source, entry.Source) != compare.EQ {
ch <- SourceFromEntries(es)
es = nil
}
es = append(es, entry)
}
if len(es) > 0 {
ch <- SourceFromEntries(es)
}
}()
return ch
}