Well, in the third draft, when the heroes find her, Leia is unconscious and beaten so badly Han actually gapes in horror at the sight of her. And Ralph McQuarrie storyboards from that time actually show Leia in a tattered dress and bare-breasted during the chasm swing.
Certainly Lucas wanted to leave it a bit ambiguous what happened “behind closed doors,” but in earlier iterations there was no escaping the point that it was extremely violent.