Struct frame_support::storage::types::OptionQuery

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pub struct OptionQuery;

Expand description

Implement QueryKindTrait with query being Option<Value>

NOTE: it doesn’t support a generic OnEmpty. This means only None can be returned when no value is found. To use another OnEmpty implementation, ValueQuery can be used instead.

Trait Implementations

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impl<Value> QueryKindTrait<Value, GetDefault> for OptionQuery where
Value: FullCodec + 'static,

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const METADATA: StorageEntryModifier

Metadata for the storage kind.

type Query = Option<Value>

Type returned on query

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fn from_optional_value_to_query(v: Option<Value>) -> Self::Query

Convert an optional value (i.e. some if trie contains the value or none otherwise) to the query. Read more

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fn from_query_to_optional_value(v: Self::Query) -> Option<Value>

Convert a query to an optional value.

Auto Trait Implementations

impl RefUnwindSafe for OptionQuery

impl Send for OptionQuery

impl Sync for OptionQuery

impl Unpin for OptionQuery

impl UnwindSafe for OptionQuery

Blanket Implementations

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

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pub 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

pub 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

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

Mutably borrows from an owned value. Read more

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impl<T> CheckedConversion for T

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fn checked_from<T>(t: T) -> Option<Self> where
Self: TryFrom<T>,

Convert from a value of T into an equivalent instance of Option<Self>. Read more

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fn checked_into<T>(self) -> Option<T> where
Self: TryInto<T>,

Consume self to return Some equivalent value of Option<T>. Read more

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

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pub fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>ⓘ
Notable traits for Box<W, Global>
`impl<W> Write for Box<W, Global> where W: Write + ?Sized, impl<R> Read for Box<R, Global> where R: Read + ?Sized, impl<I, A> Iterator for Box<I, A> where I: Iterator + ?Sized, A: Allocator, type Item = ::Item;impl<F, A> Future for Box<F, A> where F: Future + Unpin + ?Sized, A: Allocator + 'static, type Output = <F as Future>::Output;`

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

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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

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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

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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

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

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pub 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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