Enum concordium_std::Entry

pub enum Entry<'a, K, V: Serial, S: HasStateApi> {
    Vacant(VacantEntry<'a, K, V, S>),
    Occupied(OccupiedEntry<'a, K, V, S>),
}

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

This enum is constructed from the entry method on a StateMap type.

Variants

Vacant(VacantEntry<'a, K, V, S>)

Occupied(OccupiedEntry<'a, K, V, S>)

Implementations

impl<'a, K, V, StateApi> Entry<'a, K, V, StateApi> where
    K: Serial,
    V: Serial,
    StateApi: HasStateApi, 

pub fn is_vacant(&self) -> bool

Return whether the entry is vacant.

pub fn is_occupied(&self) -> bool

Return whether the entry is occupied.

pub fn occupied_or<E>(self, e: E) -> Result<OccupiedEntry<'a, K, V, StateApi>, E>

If the entry is Occupied return Ok. Otherwise return the supplied error.

pub fn vacant_or<E>(self, e: E) -> Result<VacantEntry<'a, K, V, StateApi>, E>

If the entry is Vacant return Ok. Otherwise return the supplied error.

pub fn or_insert(self, value: V) -> OccupiedEntry<'a, K, V, StateApi>

Ensure a value is in the entry by inserting the provided value if the entry is vacant.

pub fn or_insert_with<F>(self, default: F) -> OccupiedEntry<'a, K, V, StateApi> where
    F: FnOnce() -> V, 

Ensures a value is in the entry by inserting the result of the default function if empty.

pub fn and_try_modify<F, E>(self, f: F) -> Result<Entry<'a, K, V, StateApi>, E> where
    F: FnOnce(&mut V) -> Result<(), E>, 

If the entry is occupied apply the given function to its contents. If the function returns an error the contents are not updated. If the supplied function returns an error then it should not modify the given value. If it does so than the map will become inconsistent. If the entry is vacant no changes are made.

pub fn and_modify<F>(self, f: F) -> Entry<'a, K, V, StateApi> where
    F: FnOnce(&mut V), 

If the entry is occupied apply the given function to its contents. If the entry is vacant no changes are made.

pub fn key(&self) -> &K

Return a reference to this entry’s key.

impl<'a, K, V, StateApi> Entry<'a, K, V, StateApi> where
    K: Serial,
    V: Serial + Default,
    StateApi: HasStateApi, 

pub fn or_default(self) -> OccupiedEntry<'a, K, V, StateApi>

Ensures a value is in the entry by inserting the default value if empty.