Struct vtable::VRcMapped

pub struct VRcMapped<VTable: VTableMetaDropInPlace + 'static, MappedType: ?Sized> { /* private fields */ }

VRcMapped allows bundling a VRc of a type along with a reference to an object that’s reachable through the data the VRc owns and that satisfies the requirements of a Pin. VRCMapped is constructed using VRc::map and, like VRc, has a weak counterpart, VWeakMapped.

Implementations

impl<VTable: VTableMetaDropInPlace + 'static, MappedType: ?Sized> VRcMapped<VTable, MappedType>

pub fn downgrade(this: &Self) -> VWeakMapped<VTable, MappedType>

Returns a new VWeakMapped that points to this instance and can be upgraded back to a Self as long as a VRc/VMapped exists.

pub fn as_pin_ref(&self) -> Pin<&MappedType>

Create a Pinned reference to the mapped type.

This is safe because the map function returns a pinned reference.

pub fn map<ReMappedType: ?Sized>(
    this: Self,
    map_fn: impl for<'r> FnOnce(Pin<&'r MappedType>) -> Pin<&'r ReMappedType>
) -> VRcMapped<VTable, ReMappedType>

This function allows safely holding a reference to a field inside the VRcMapped. In order to accomplish that, you need to provide a mapping function map_fn in which you need to provide and return a pinned reference to the object you would like to map. The returned VRcMapped allows obtaining that pinned reference again using VRcMapped::as_pin_ref.

See also VRc::map

pub fn origin(this: &Self) -> VRc<VTable>

Returns a strong reference to the object that the mapping originates from.

Trait Implementations

impl<VTable: VTableMetaDropInPlace + 'static, MappedType: ?Sized> Clone for VRcMapped<VTable, MappedType>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<VTable: VTableMetaDropInPlace + 'static, MappedType: ?Sized> Deref for VRcMapped<VTable, MappedType>

type Target = MappedType

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.