Struct cw_storage_plus::Item

pub struct Item<'a, T> { /* fields omitted */ }

Item stores one typed item at the given key. This is an analog of Singleton. It functions just as Path but doesn't ue a Vec and thus has a const fn constructor.

Implementations

impl<'a, T> Item<'a, T>

pub const fn new(storage_key: &'a [u8]) -> Self

impl<'a, T> Item<'a, T> where
    T: Serialize + DeserializeOwned, 

pub fn as_slice(&self) -> &[u8]

pub fn save<S: Storage>(&self, store: &mut S, data: &T) -> StdResult<()>

save will serialize the model and store, returns an error on serialization issues

pub fn remove<S: Storage>(&self, store: &mut S)

pub fn load<S: Storage>(&self, store: &S) -> StdResult<T>

load will return an error if no data is set at the given key, or on parse error

pub fn may_load<S: Storage>(&self, store: &S) -> StdResult<Option<T>>

may_load will parse the data stored at the key if present, returns Ok(None) if no data there. returns an error on issues parsing

pub fn update<A, E, S>(&mut self, store: &mut S, action: A) -> Result<T, E> where
    A: FnOnce(T) -> Result<T, E>,
    E: From<StdError>,
    S: Storage, 

Loads the data, perform the specified action, and store the result in the database. This is shorthand for some common sequences, which may be useful.

If the data exists, action(Some(value)) is called. Otherwise action(None) is called.