Enum zng_state_map::state_map::StateMapEntry

pub enum StateMapEntry<'a, T: StateValue> {
    Occupied(OccupiedStateMapEntry<'a, T>),
    Vacant(VacantStateMapEntry<'a, T>),
}

A view into a single entry in a state map, which may either be vacant or occupied.

This enum is constructed from the entry method on StateMapMut.

Variants

Occupied(OccupiedStateMapEntry<'a, T>)

An occupied entry.

Vacant(VacantStateMapEntry<'a, T>)

A vacant entry.

Implementations

impl<'a, T: StateValue> StateMapEntry<'a, T>

pub fn or_insert(self, default: impl Into<T>) -> &'a mut T

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

pub fn or_insert_with<F: FnOnce() -> T>(self, default: F) -> &'a mut T

Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.

pub fn and_modify<F: FnOnce(&mut T)>(self, f: F) -> Self

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

impl<'a, T> StateMapEntry<'a, T>

where T: Default + StateValue,

pub fn or_default(self) -> &'a mut T

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

Trait Implementations

impl<'a, T: StateValue + Debug> Debug for StateMapEntry<'a, T>

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

Formats the value using the given formatter.