Expand description
Store a cached key/value pair, only recalculating when the key changes.
Fields
contents: Option<(K, V)>
Implementations
sourceimpl<K: PartialEq + Clone, V> Cached<K, V>
impl<K: PartialEq + Clone, V> Cached<K, V>
pub fn new() -> Cached<K, V>
sourcepub fn update<F: FnMut(K) -> V>(&mut self, key: Option<K>, produce_value: F)
pub fn update<F: FnMut(K) -> V>(&mut self, key: Option<K>, produce_value: F)
Update the value if the key has changed.
sourcepub fn set(&mut self, key: K, value: V)
pub fn set(&mut self, key: K, value: V)
update
is preferred, but sometimes produce_value
needs to borrow the same struct that
owns this Cached
. In that case, the caller can manually check key
and call this.
pub fn clear(&mut self)
Trait Implementations
Auto Trait Implementations
impl<K, V> RefUnwindSafe for Cached<K, V> where
K: RefUnwindSafe,
V: RefUnwindSafe,
impl<K, V> Send for Cached<K, V> where
K: Send,
V: Send,
impl<K, V> Sync for Cached<K, V> where
K: Sync,
V: Sync,
impl<K, V> Unpin for Cached<K, V> where
K: Unpin,
V: Unpin,
impl<K, V> UnwindSafe for Cached<K, V> where
K: UnwindSafe,
V: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
impl<T> Downcast for T where
T: Any,
impl<T> Downcast for T where
T: Any,
pub fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
pub fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
Convert Box<dyn Trait>
(where Trait: Downcast
) to Box<dyn Any>
. Box<dyn Any>
can
then be further downcast
into Box<ConcreteType>
where ConcreteType
implements Trait
. Read more
pub fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
pub fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
Convert Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
. Rc<Any>
can then be
further downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
. Read more
pub fn as_any(&self) -> &(dyn Any + 'static)
pub fn as_any(&self) -> &(dyn Any + 'static)
Convert &Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s. Read more
pub fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
pub fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
Convert &mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s. Read more
sourceimpl<T> Instrument for T
impl<T> Instrument for T
sourcefn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
Instruments this type with the provided Span
, returning an
Instrumented
wrapper. Read more
sourcefn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
impl<T> Same<T> for T
impl<T> Same<T> for T
type Output = T
type Output = T
Should always be Self