src/unchecked_any.rs - anymap blob - Chris Morgan’s Git repositories

   1 use std::any::Any;
   2 use std::mem;
   3 use std::raw::TraitObject;
   4
   5 #[allow(missing_docs)]  // Bogus warning (it’s not public outside the crate), ☹
   6 pub trait UncheckedAnyExt {
   7     unsafe fn downcast_ref_unchecked<T: 'static>(&self) -> &T;
   8     unsafe fn downcast_mut_unchecked<T: 'static>(&mut self) -> &mut T;
   9     unsafe fn downcast_unchecked<T: 'static>(self: Box<Self>) -> Box<T>;
  10 }
  11
  12 impl UncheckedAnyExt for Any {
  13     unsafe fn downcast_ref_unchecked<T: 'static>(&self) -> &T {
  14         mem::transmute(mem::transmute::<_, TraitObject>(self).data)
  15     }
  16
  17     unsafe fn downcast_mut_unchecked<T: 'static>(&mut self) -> &mut T {
  18         mem::transmute(mem::transmute::<_, TraitObject>(self).data)
  19     }
  20
  21     unsafe fn downcast_unchecked<T: 'static>(self: Box<Any>) -> Box<T> {
  22         mem::transmute(mem::transmute::<_, TraitObject>(self).data)
  23     }
  24 }