dope-runtime 0.44.0

Thread-per-core execution and process lifecycle for dope
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
30
31
32
33
34
35
36
37
38
39
40
41

use std::{mem, pin};

/// # Safety
/// Both projections retain the same pinned application through its final traversal.
/// The enclosing lifecycle ends all projection access before releasing its storage.
pub unsafe trait Project {
    type App;

    fn shared(self: pin::Pin<&Self>) -> pin::Pin<&Self::App>;

    fn exclusive(self: pin::Pin<&mut Self>) -> pin::Pin<&mut Self::App>;
}

// SAFETY: the original mutable Pin retains its owner at the same address.
unsafe impl<T> Project for pin::Pin<&mut T> {
    type App = T;

    fn shared(self: pin::Pin<&Self>) -> pin::Pin<&T> {
        self.get_ref().as_ref()
    }

    fn exclusive(self: pin::Pin<&mut Self>) -> pin::Pin<&mut T> {
        self.get_mut().as_mut()
    }
}

// SAFETY: ManuallyDrop is transparent and the enclosing owner pins its value
// until final traversal releases it exactly once.
unsafe impl<T> Project for mem::ManuallyDrop<T> {
    type App = T;

    fn shared(self: pin::Pin<&Self>) -> pin::Pin<&T> {
        // SAFETY: the projection retains the enclosing pin and initialized value.
        unsafe { self.map_unchecked(|value| &**value) }
    }

    fn exclusive(self: pin::Pin<&mut Self>) -> pin::Pin<&mut T> {
        // SAFETY: the projection retains the enclosing pin without moving T.
        unsafe { self.map_unchecked_mut(|value| &mut **value) }
    }
}