Enum Entry

pub(crate) enum Entry<V> {
    Present(V),
    Unusable,
}

A single entry in one of our careful slotmaps.

An entry can either be Present (in which case we treat it normally), or Unusable, in which case we

Variants

Present(V)

The entry is available.

Unusable

The entry can no longer be used, removed, or set to anything else.

It must not be removed from the slot map, since doing so would increase its slot’s version number too high.

Implementations

impl<V> Entry<V>

pub(crate) fn take_and_mark_unusable(&mut self) -> Option<V>

Remove the value of self (if any), and make it unusable.

pub(crate) fn value(&self) -> Option<&V>

Return a reference to the value of self, if there is one.

pub(crate) fn value_mut(&mut self) -> Option<&mut V>

Return a mutable reference to the value of `self``, if there is one.

pub(crate) fn unwrap(self) -> V

Consume this entry (which must be Present), and return its value.

Panics

Panics if this entry is Unusable.

Trait Implementations

impl<V: Clone> Clone for Entry<V>

fn clone(&self) -> Entry<V>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<V: Debug> Debug for Entry<V>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.