Although reading adult stories is legal for adults over 18 in Sri Lanka, is a grey area. Under the Computer Crimes Act No. 24 of 2007, sharing obscene publications via electronic means can lead to fines or imprisonment. If you share a Google Drive link containing explicit Sinhala content with a minor (even accidentally via a forwarded link), you are criminally liable.
The "Google Drive" era is a symptom of an immature digital ecosystem. As Sri Lanka's digital payment systems improve (e.g., PayHere, FriMi, eZ Cash), more authors will move to pay-per-story microtransactions.