Struct storage_api::RawBox

pub struct RawBox<T: ?Sized, S: Storage> { /* private fields */ }

A raw box around some storage. Bundles the storage and its handle.

Implementations

impl<T: ?Sized, S: Storage> RawBox<T, S>

pub unsafe fn new(
    metadata: <T as Pointee>::Metadata,
    storage: S
) -> Result<Self, S>

Create a new box for the object described by the given metadata.

The object is not initialized.

(Do we want a new_zeroed?)

Safety

• The metadata must describe a layout valid for a rust object.
  • This requirement exists due to the safety requirements of size_of_val_raw and align_of_val_raw. I think we definitely want a way to go compute layout from type and metadata safely, with a check that it produces a valid layout.
  • On each unsized kind, this would imply:
    • slices: size computation uses saturating/checked multiplication.
    • traits: vtable must always be valid (as a safety invariant).
    • composites: size computation uses saturating/checked addition.
    • externs: any valid metadata must compute valid size/align or indicates that size/align is unknown and/or needs a valid object.
  • rust-lang/rust#95832 is an attempt to quantize how expensive it would be to make slice size computation always use saturating math.

pub fn as_ref(&self) -> &MaybeUninit<T> where
    T: Sized, 

Get a reference to the boxed object.

pub fn as_ptr(&self) -> *const T

Get a pointer valid for reads only to the boxed object.

The pointer is invalidated when the box is moved or used by mutable reference.

pub fn as_mut(&mut self) -> &mut MaybeUninit<T> where
    T: Sized, 

Get a mutable reference to the boxed object.

pub fn as_mut_ptr(&mut self) -> *mut T

Get a pointer valid for reads and writes to the boxed object.

The pointer is invalidated when the box is moved or used by reference.

pub fn metadata(&self) -> <T as Pointee>::Metadata

Get the metadata of the boxed object.

pub fn into_raw_parts(self) -> (S::Handle, <T as Pointee>::Metadata, S)

Break a raw box into its component parts.

pub unsafe fn from_raw_parts(
    handle: S::Handle,
    metadata: <T as Pointee>::Metadata,
    storage: S
) -> Self

Reassemble a raw box from its component parts.

Trait Implementations

impl<T: ?Sized, S: Storage> Drop for RawBox<T, S>

fn drop(&mut self)

Executes the destructor for this type.