Struct Casts

pub struct Casts { /* private fields */ }

Stores known ways to cast from concrete types to trait objects.

Implementations

impl Casts

pub unsafe fn add<T, U>(&mut self, cast: fn(*const T) -> *const U)

where T: 'static, U: ?Sized + 'static,

Adds a cast from T to U.

Safety

The provided function must not do anything except trivially return the pointer that it is given, potentially with a vtable attached.

pub fn find_key(&self, src_type: TypeId, dst_type: TypeId) -> Option<u32>

Looks up an index that can be used to quickly access a cast from the source type to the destination type, via Casts::cast.

pub fn cast<Dst>(&self, key: u32, src: *const ()) -> *const Dst

where Dst: ?Sized + 'static,

Casts the input type-erased pointer into the destination type. The resulting pointer is only safe to dereference if the underlying type behind the src pointer is the right source type for the given cast index.

pub fn get_dst(&self, key: u32) -> TypeId

Looks up the destination type for the given cast.

pub fn get_src(&self, key: u32) -> TypeId

Looks up the source type for the given cast.

pub fn find_keys_by_dst<'a>( &'a self, ty: TypeId, ) -> impl Iterator<Item = (TypeId, u32)> + 'a

Iterates over known casts into the given target type. Items in the returned iterator are (source type, cast key).

pub fn find_keys_by_src<'a>( &'a self, ty: TypeId, ) -> impl Iterator<Item = (TypeId, u32)> + 'a

Iterates over known casts out of the given source type. Items in the returned iterator are (target type, cast key).

Trait Implementations

impl Default for Casts

fn default() -> Casts

Returns the “default value” for a type.

impl Send for Casts

impl Sync for Casts