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use std::mem;
pub trait Leak<T : ?Sized> {
fn leak<'a>(self) -> &'a T where T: 'a;
}
impl<T : ?Sized> Leak<T> for Box<T> {
fn leak<'a>(self) -> &'a T where T: 'a {
let r = Self::into_raw(self);
unsafe { &mut *r }
}
}
impl Leak<str> for String {
fn leak<'a>(mut self) -> &'a str where Self: 'a {
let r: *mut str = &mut self[..];
mem::forget(self);
unsafe { &mut *r }
}
}
impl<T> Leak<[T]> for Vec<T> {
fn leak<'a>(mut self) -> &'a [T] where [T]: 'a {
let r: *mut [T] = &mut self[..];
mem::forget(self);
unsafe { &mut *r }
}
}
#[cfg(test)]
mod test {
#[test]
fn leak_str() {
use super::Leak;
use std::borrow::ToOwned;
let v = "hi";
let leaked : &str = {
let o = v.to_owned();
o.leak()
};
assert_eq!(leaked, v);
let leaked : &'static str = {
let o = v.to_owned();
o.leak()
};
assert_eq!(leaked, v);
}
#[test]
fn leak_empty_str() {
use super::Leak;
use std::borrow::ToOwned;
let v = "";
let leaked : &'static str = {
let o = v.to_owned();
o.leak()
};
assert_eq!(leaked, v);
}
#[test]
fn leak_vec() {
use super::Leak;
let v = vec![3, 5];
let leaked : &'static [u8] = {
let o = v.clone();
o.leak()
};
assert_eq!(leaked, &*v);
}
#[test]
fn leak_empty_vec() {
use super::Leak;
let v = vec![];
let leaked : &'static [u8] = {
let o = v.clone();
o.leak()
};
assert_eq!(leaked, &*v);
}
#[test]
fn leak_box() {
use super::Leak;
let v : Box<[&str]> = vec!["hi", "there"].into_boxed_slice();
let leaked : &'static [&str] = {
let o = v.clone();
o.leak()
};
assert_eq!(leaked, &*v);
}
#[test]
fn leak_nested() {
use super::Leak;
let v : Box<Vec<&str>> = Box::new(vec!["hi", "there"]);
let leaked : &'static [&str] = {
let o = v.clone();
o.leak()
};
assert_eq!(leaked, &**v);
}
}