Enum Calf

pub enum Calf<'own, BorrowedT> {
    Borrowed(&'own BorrowedT),
    Owned(BorrowedT),
}

A read-only container for either an owned value or a reference to one.

Similar to Cow, but does not support ToOwned (and does not require your value to support it), nor does it support BorrowMut.

It’s a baby cow!

Note that after coming up with the idea for this, I discovered that someone else did, too. Check out maybe-owned for an identical type that comes with a zillion more trait implementations.

Variants

Borrowed(&'own BorrowedT)

Borrowed.

Owned(BorrowedT)

Owned.

Implementations

impl<'own, BorrowedT> Calf<'own, BorrowedT>

pub fn is_borrowed(&self) -> bool

Are we borrowed?

pub fn is_owned(&self) -> bool

Are we owned?

impl<'own, BorrowedT, OwnedT> Calf<'own, BorrowedT>

where BorrowedT: ToOwned<Owned = OwnedT>,

pub fn into_owned(self) -> <BorrowedT as ToOwned>::Owned

Into owned.

Trait Implementations

impl<'own, BorrowedT> Borrow<BorrowedT> for Calf<'own, BorrowedT>

fn borrow(&self) -> &BorrowedT

Immutably borrows from an owned value.

impl<'own, BorrowedT> BorrowMut<BorrowedT> for Calf<'own, BorrowedT>

where &'own BorrowedT: AsMut<&'own mut BorrowedT>,

fn borrow_mut(&mut self) -> &mut BorrowedT

Mutably borrows from an owned value.

impl<'own, BorrowedT> From<Cow<'own, BorrowedT>> for Calf<'own, BorrowedT>

where BorrowedT: ToOwned<Owned = BorrowedT>,

fn from(cow: Cow<'own, BorrowedT>) -> Self

Converts to this type from the input type.

impl<'own, BorrowedT> Into<Cow<'own, BorrowedT>> for Calf<'own, BorrowedT>

where BorrowedT: ToOwned<Owned = BorrowedT>,

fn into(self) -> Cow<'own, BorrowedT>

Converts this type into the (usually inferred) input type.

impl<'own, BorrowedT, OwnedT> ToOwned for Calf<'own, BorrowedT>

where BorrowedT: ToOwned<Owned = OwnedT>, OwnedT: Borrow<Self>,

type Owned = OwnedT

The resulting type after obtaining ownership.

fn to_owned(&self) -> OwnedT

Creates owned data from borrowed data, usually by cloning.

fn clone_into(&self, target: &mut Self::Owned)

Uses borrowed data to replace owned data, usually by cloning.