[][src]Struct cosmwasm_storage::Singleton

pub struct Singleton<'a, S: Storage, T> where
    T: Serialize + DeserializeOwned
{ /* fields omitted */ }

Singleton effectively combines PrefixedStorage with TypedStorage to work on a single storage key. It performs the to_length_prefixed transformation on the given name to ensure no collisions, and then provides the standard TypedStorage accessors, without requiring a key (which is defined in the constructor)


impl<'a, S: Storage, T> Singleton<'a, S, T> where
    T: Serialize + DeserializeOwned

pub fn new(storage: &'a mut S, key: &[u8]) -> Self[src]

pub fn save(&mut self, data: &T) -> StdResult<()>[src]

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

pub fn load(&self) -> StdResult<T>[src]

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

pub fn may_load(&self) -> StdResult<Option<T>>[src]

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>(&mut self, action: A) -> StdResult<T> where
    A: FnOnce(T) -> StdResult<T>, 

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

This is the least stable of the APIs, and definitely needs some usage

Auto Trait Implementations

impl<'a, S, T> RefUnwindSafe for Singleton<'a, S, T> where
    S: RefUnwindSafe,
    T: RefUnwindSafe

impl<'a, S, T> Send for Singleton<'a, S, T> where
    S: Send,
    T: Sync

impl<'a, S, T> Sync for Singleton<'a, S, T> where
    S: Sync,
    T: Sync

impl<'a, S, T> Unpin for Singleton<'a, S, T>

impl<'a, S, T> !UnwindSafe for Singleton<'a, S, T>

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized

impl<T> Borrow<T> for T where
    T: ?Sized

impl<T> BorrowMut<T> for T where
    T: ?Sized

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.