Struct widgetry::tools::Cached

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pub struct Cached<K: PartialEq + Clone, V> {
    contents: Option<(K, V)>,
}

Expand description

Store a cached key/value pair, only recalculating when the key changes.

Fields

contents: Option<(K, V)>

Implementations

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impl<K: PartialEq + Clone, V> Cached<K, V>

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pub fn new() -> Cached<K, V>

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pub fn key(&self) -> Option<K>

Get the current key.

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pub fn value(&self) -> Option<&V>

Get the current value.

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pub fn value_mut(&mut self) -> Option<&mut V>

Get the current value, mutably.

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pub fn update<F: FnMut(K) -> V>(&mut self, key: Option<K>, produce_value: F)

Update the value if the key has changed.

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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.

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pub fn clear(&mut self)

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pub fn take(&mut self) -> Option<(K, V)>

Clears the current pair and returns it.

Trait Implementations

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impl<K: PartialEq + Clone, V> Default for Cached<K, V>

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fn default() -> Self

Returns the “default value” for a type. Read more

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

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

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

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

impl<T> Downcast for T where
T: Any,

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

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

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

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

impl<T> DowncastSync for T where
T: Any + Send + Sync,

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send + 'static>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait. Read more

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impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

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

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

Performs the conversion.

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

type Error = >::Error

The type returned in the event of a conversion error.

const: unstable · source

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

Struct widgetry::tools::Cached

Fields

Implementations

impl<K: PartialEq + Clone, V> Cached<K, V>

pub fn new() -> Cached<K, V>

pub fn key(&self) -> Option<K>

pub fn value(&self) -> Option<&V>

pub fn value_mut(&mut self) -> Option<&mut V>

pub fn update<F: FnMut(K) -> V>(&mut self, key: Option<K>, produce_value: F)

pub fn set(&mut self, key: K, value: V)

pub fn clear(&mut self)

pub fn take(&mut self) -> Option<(K, V)>

Trait Implementations

impl<K: PartialEq + Clone, V> Default for Cached<K, V>

fn default() -> Self

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

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

fn type_id(&self) -> TypeId

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

fn borrow(&self) -> &T

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

fn borrow_mut(&mut self) -> &mut T

impl<T> Downcast for T where T: Any,

fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>

fn as_any(&self) -> &(dyn Any + 'static)

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

impl<T> DowncastSync for T where T: Any + Send + Sync,

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send + 'static>

impl<T> From<T> for T

fn from(t: T) -> T

impl<T> Instrument for T

fn instrument(self, span: Span) -> Instrumented<Self>

fn in_current_span(self) -> Instrumented<Self>

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

fn into(self) -> U

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

type Error = Infallible

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

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

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

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

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,

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> Downcast for T where
T: Any,

impl<T> DowncastSync for T where
T: Any + Send + Sync,

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

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

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