1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

#![cfg_attr(test, deny(warnings))]
#![deny(missing_docs)]

//! # traitobject
//!
//! Unsafe helpers for working with raw TraitObjects.

use std::mem;

/// Get the data pointer from this trait object.
///
/// Highly unsafe, as there is no information about the type of the data.
pub unsafe fn data<T: ?Sized>(val: *const T) -> *const () {
    *mem::transmute::<*const *const T, *const *const ()>(&val)
}

/// Get the data pointer from this trait object, mutably.
///
/// Highly unsafe, as there is no information about the type of the data.
pub unsafe fn data_mut<T: ?Sized>(mut val: *mut T) -> *mut () {
    *mem::transmute::<*mut *mut T, *mut *mut ()>(&mut val)
}

#[test]
fn test_simple() {
    let x = &7 as &Send;
    unsafe { assert!(&7 == mem::transmute::<_, &i32>(data(x))) };
}