Trait AllocSliceDst

pub unsafe trait AllocSliceDst<S: ?Sized + SliceDst> {
    // Required method
    unsafe fn new_slice_dst<I>(len: usize, init: I) -> Self
       where I: FnOnce(NonNull<S>);
}

Types that can allocate a custom slice DST within them.

Implementation note

For most types, TryAllocSliceDst should be the implementation primitive. This trait can then be implemented in terms of TryAllocSliceDst:

unsafe impl<S: ?Sized + SliceDst> AllocSliceDst<S> for Container<S> {
    unsafe fn new_slice_dst<I>(len: usize, init: I) -> Self
    where
        I: FnOnce(ptr::NonNull<S>),
    {
        enum Void {} // or never (!) once it is stable
        #[allow(clippy::unit_arg)]
        let init = |ptr| Ok::<(), Void>(init(ptr));
        match Self::try_new_slice_dst(len, init) {
            Ok(a) => a,
            Err(void) => match void {},
        }
    }
}

This is not a blanket impl due to coherence rules; if the blanket impl were present, it would be impossible to implement AllocSliceDst instead of TryAllocSliceDst.

Required Methods

unsafe fn new_slice_dst<I>(len: usize, init: I) -> Self

where I: FnOnce(NonNull<S>),

Create a new custom slice DST.

Safety

init must properly initialize the object behind the pointer. init receives a fully uninitialized pointer and must not read anything before writing.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<S: ?Sized + SliceDst> AllocSliceDst<S> for Box<S>

unsafe fn new_slice_dst<I>(len: usize, init: I) -> Self

where I: FnOnce(NonNull<S>),

impl<S: ?Sized + SliceDst> AllocSliceDst<S> for Rc<S>

unsafe fn new_slice_dst<I>(len: usize, init: I) -> Self

where I: FnOnce(NonNull<S>),

impl<S: ?Sized + SliceDst> AllocSliceDst<S> for Arc<S>

unsafe fn new_slice_dst<I>(len: usize, init: I) -> Self

where I: FnOnce(NonNull<S>),

Implementors