Crate ptr_meta

Expand description

A radioactive stabilization of the ptr_meta RFC.

Usage

Sized types

All Sized types have Pointee implemented for them with a blanket implementation. You do not need to derive Pointee for these types.

`slice`s and `str`s

These core types have implementations built in.

`dyn Any`

The trait object for this standard library type comes with an implementation built in.

Structs with a DST as its last field

You can derive Pointee for structs with a trailing DST:

use ptr_meta::Pointee;

#[derive(Pointee)]
struct Block<H, T> {
    header: H,
    elements: [T],
}

Note that this will only work when the last field is guaranteed to be a DST. Structs with a generic last field may have a conflicting blanket impl since the generic type may be Sized. In these cases, a collection of specific implementations may be required with the generic parameter set to a slice, str, or specific trait object.

Trait objects

You can generate a Pointee implementation for trait objects:

use ptr_meta::pointee;

// Generates Pointee for dyn Stringy
#[pointee]
trait Stringy {
    fn as_string(&self) -> String;
}

Structs

DynMetadata

The metadata for a Dyn = dyn SomeTrait trait object type.

Traits

NonNullExt

Extension methods for NonNull.

Pointee

Provides the pointer metadata type of any pointed-to type.

PtrExt

Extension methods for pointers.

Functions

from_raw_parts

Forms a (possibly wide) raw pointer from a data address and metadata.

from_raw_parts_mut

Performs the same functionality as from_raw_parts, except that a raw *mut pointer is returned, as opposed to a raw *const pointer.

metadata

Returns the metadata component of a pointer.

Attribute Macros

pointee

Generates an implementation of Pointee for trait objects.

Derive Macros

Pointee

Generates an implementation of Pointee for structs with a DST as its last field.