Struct concordium_std::StateRefMut

pub struct StateRefMut<'a, V: Serial, S: HasStateApi> { /* private fields */ }

The StateRefMut<_, V, _> behaves like &mut V, by analogy with other standard library RAII guards like RefMut. The type implements DerefMut which allows the value to be mutated. Additionally, the Drop implementation ensures that the value is properly stored in the contract state maintained by the node.

Implementations

impl<'a, V, S> StateRefMut<'a, V, S> where
    V: Serial + DeserialWithState<S>,
    S: HasStateApi, 

pub fn get(&self) -> &V

Get a shared reference to the value. Note that StateRefMut also implements Deref so this conversion can happen implicitly.

pub fn get_mut(&mut self) -> &mut V

Get a unique reference to the value. Note that StateRefMut also implements DerefMut so this conversion can happen implicitly.

pub fn set(&mut self, new_val: V)

Set the value. Overwrites the existing one.

pub fn update<F>(&mut self, f: F) where
    F: FnOnce(&mut V), 

Update the existing value with the given function.

Trait Implementations

impl<'a, V: Debug + Serial, S: Debug + HasStateApi> Debug for StateRefMut<'a, V, S> where
    S::EntryType: Debug, 

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

Formats the value using the given formatter.

impl<'a, S: HasStateApi, V: Serial + DeserialWithState<S>> Deref for StateRefMut<'a, V, S>

type Target = V

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'a, S: HasStateApi, V: Serial + DeserialWithState<S>> DerefMut for StateRefMut<'a, V, S>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'a, V: Serial, S: HasStateApi> Drop for StateRefMut<'a, V, S>

When dropped, the value, V, is written to the entry in the contract state.

fn drop(&mut self)

Executes the destructor for this type.