Enum MaybeCached

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#[non_exhaustive]pub enum MaybeCached<'a, T: 'a> {
    CannotCache(T),
    Cached(&'a mut T),
}

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Expand description

Wraps a possibly cached prepared statement

Essentially a customized version of Cow that does not depend on ToOwned

Variants (Non-exhaustive)§

This enum is marked as non-exhaustive

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

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CannotCache(T)

Contains a not cached prepared statement

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Cached(&'a mut T)

Contains a reference cached prepared statement

Trait Implementations§

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impl<T> Deref for MaybeCached<'_, T>

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type Target = T

The resulting type after dereferencing.

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

Dereferences the value.

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impl<T> DerefMut for MaybeCached<'_, T>

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

Mutably dereferences the value.

Auto Trait Implementations§

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impl<'a, T> !UnwindSafe for MaybeCached<'a, T>

Blanket Implementations§

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impl<T> AggregateExpressionMethods for T

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fn aggregate_distinct(self) -> AggregateDistinct<Self>
where Self: DistinctDsl,

DISTINCT modifier for aggregate functions Read more

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fn aggregate_all(self) -> AggregateAll<Self>
where Self: AllDsl,

ALL modifier for aggregate functions Read more

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fn aggregate_filter(self, f: P) -> AggregateFilter<Self, P>
where P: AsExpression<Bool>, Self: FilterDsl<P::Expression>,

Add an aggregate function filter Read more

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fn aggregate_order<O>(self, o: O) -> AggregateOrder<Self, O>
where Self: OrderAggregateDsl<O>,

Add an aggregate function order Read more

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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,

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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,

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

Mutably borrows from an owned value. Read more

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

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fn into_any(self: Box<T>) -> Box<dyn Any>

Converts Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>, which can then be downcast into Box<dyn ConcreteType> where ConcreteType implements Trait.

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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Converts Rc<Trait> (where Trait: Downcast) to Rc<Any>, which can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.

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

Converts &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.

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

Converts &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.

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impl<T> DowncastSend for T
where T: Any + Send,

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fn into_any_send(self: Box<T>) -> Box<dyn Any + Send>

Converts Box<Trait> (where Trait: DowncastSend) to Box<dyn Any + Send>, which can then be downcast into Box<ConcreteType> where ConcreteType implements Trait.

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

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fn into_any_sync(self: Box<T>) -> Box<dyn Any + Sync + Send>

Converts Box<Trait> (where Trait: DowncastSync) to Box<dyn Any + Send + Sync>, which can then be downcast into Box<ConcreteType> where ConcreteType implements Trait.

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fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send>

Converts Arc<Trait> (where Trait: DowncastSync) to Arc<Any>, which can then be downcast into Arc<ConcreteType> where ConcreteType implements Trait.

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