Struct frame_support::pallet_prelude::StorageValue [−][src]
A type that allow to store a value.
Each value is stored at:
Twox128(Prefix::pallet_prefix()) ++ Twox128(Prefix::STORAGE_PREFIX)
Implementations
impl<Prefix, Value, QueryKind, OnEmpty> StorageValue<Prefix, Value, QueryKind, OnEmpty> where
Prefix: StorageInstance,
Value: FullCodec,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
[src]
Prefix: StorageInstance,
Value: FullCodec,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
pub fn hashed_key() -> [u8; 32]
[src]
Get the storage key.
pub fn exists() -> bool
[src]
Does the value (explicitly) exist in storage?
pub fn get() -> QueryKind::Query
[src]
Load the value from the provided storage instance.
pub fn try_get() -> Result<Value, ()>
[src]
Try to get the underlying value from the provided storage instance; Ok
if it exists,
Err
if not.
pub fn translate<O: Decode, F: FnOnce(Option<O>) -> Option<Value>>(
f: F
) -> Result<Option<Value>, ()>
[src]
f: F
) -> Result<Option<Value>, ()>
Translate a value from some previous type (O
) to the current type.
f: F
is the translation function.
Returns Err
if the storage item could not be interpreted as the old type, and Ok, along
with the new value if it could.
NOTE: This operates from and to Option<_>
types; no effort is made to respect the default
value of the original type.
Warning
This function must be used with care, before being updated the storage still contains the
old type, thus other calls (such as get
) will fail at decoding it.
Usage
This would typically be called inside the module implementation of on_runtime_upgrade,
while ensuring no usage of this storage are made before the call to
on_runtime_upgrade
. (More precisely prior initialized modules doesn’t make use of this
storage).
pub fn put<Arg: EncodeLike<Value>>(val: Arg)
[src]
Store a value under this key into the provided storage instance.
pub fn set(val: QueryKind::Query)
[src]
Store a value under this key into the provided storage instance.
this uses the query type rather than the underlying value.
pub fn mutate<R, F: FnOnce(&mut QueryKind::Query) -> R>(f: F) -> R
[src]
Mutate the value
pub fn try_mutate<R, E, F: FnOnce(&mut QueryKind::Query) -> Result<R, E>>(
f: F
) -> Result<R, E>
[src]
f: F
) -> Result<R, E>
Mutate the value if closure returns Ok
pub fn kill()
[src]
Clear the storage value.
pub fn take() -> QueryKind::Query
[src]
Take a value from storage, removing it afterwards.
pub fn append<Item, EncodeLikeItem>(item: EncodeLikeItem) where
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
Value: StorageAppend<Item>,
[src]
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
Value: StorageAppend<Item>,
Append the given item to the value in the storage.
Value
is required to implement StorageAppend
.
Warning
If the storage item is not encoded properly, the storage item will be overwritten
and set to [item]
. Any default value set for the storage item will be ignored
on overwrite.
pub fn decode_len() -> Option<usize> where
Value: StorageDecodeLength,
[src]
Value: StorageDecodeLength,
Read the length of the storage value without decoding the entire value.
Value
is required to implement StorageDecodeLength
.
If the value does not exists or it fails to decode the length, None
is returned.
Otherwise Some(len)
is returned.
Warning
None
does not mean that get()
does not return a value. The default value is completly
ignored by this function.
Trait Implementations
impl<Prefix, Value, QueryKind, OnEmpty> StorageValueMetadata for StorageValue<Prefix, Value, QueryKind, OnEmpty> where
Prefix: StorageInstance,
Value: FullCodec,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
[src]
Prefix: StorageInstance,
Value: FullCodec,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
const MODIFIER: StorageEntryModifier
[src]
const NAME: &'static str
[src]
const DEFAULT: DefaultByteGetter
[src]
Auto Trait Implementations
impl<Prefix, Value, QueryKind, OnEmpty> RefUnwindSafe for StorageValue<Prefix, Value, QueryKind, OnEmpty> where
OnEmpty: RefUnwindSafe,
Prefix: RefUnwindSafe,
QueryKind: RefUnwindSafe,
Value: RefUnwindSafe,
OnEmpty: RefUnwindSafe,
Prefix: RefUnwindSafe,
QueryKind: RefUnwindSafe,
Value: RefUnwindSafe,
impl<Prefix, Value, QueryKind, OnEmpty> Send for StorageValue<Prefix, Value, QueryKind, OnEmpty> where
OnEmpty: Send,
Prefix: Send,
QueryKind: Send,
Value: Send,
OnEmpty: Send,
Prefix: Send,
QueryKind: Send,
Value: Send,
impl<Prefix, Value, QueryKind, OnEmpty> Sync for StorageValue<Prefix, Value, QueryKind, OnEmpty> where
OnEmpty: Sync,
Prefix: Sync,
QueryKind: Sync,
Value: Sync,
OnEmpty: Sync,
Prefix: Sync,
QueryKind: Sync,
Value: Sync,
impl<Prefix, Value, QueryKind, OnEmpty> Unpin for StorageValue<Prefix, Value, QueryKind, OnEmpty> where
OnEmpty: Unpin,
Prefix: Unpin,
QueryKind: Unpin,
Value: Unpin,
OnEmpty: Unpin,
Prefix: Unpin,
QueryKind: Unpin,
Value: Unpin,
impl<Prefix, Value, QueryKind, OnEmpty> UnwindSafe for StorageValue<Prefix, Value, QueryKind, OnEmpty> where
OnEmpty: UnwindSafe,
Prefix: UnwindSafe,
QueryKind: UnwindSafe,
Value: UnwindSafe,
OnEmpty: UnwindSafe,
Prefix: UnwindSafe,
QueryKind: UnwindSafe,
Value: UnwindSafe,
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
[src]
impl<T> CheckedConversion for T
[src]
pub fn checked_from<T>(t: T) -> Option<Self> where
Self: TryFrom<T>,
[src]
Self: TryFrom<T>,
pub fn checked_into<T>(self) -> Option<T> where
Self: TryInto<T>,
[src]
Self: TryInto<T>,
impl<T> From<T> for T
[src]
impl<T> Instrument for T
[src]
pub fn instrument(self, span: Span) -> Instrumented<Self>
[src]
pub fn in_current_span(self) -> Instrumented<Self>
[src]
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T> IsType<T> for T
[src]
pub fn from_ref(&T) -> &T
[src]
pub fn into_ref(&Self) -> &T
[src]
pub fn from_mut(&mut T) -> &mut T
[src]
pub fn into_mut(&mut Self) -> &mut T
[src]
impl<T, Outer> IsWrappedBy<Outer> for T where
T: From<Outer>,
Outer: AsRef<T> + AsMut<T> + From<T>,
[src]
T: From<Outer>,
Outer: AsRef<T> + AsMut<T> + From<T>,
pub fn from_ref(outer: &Outer) -> &T
[src]
Get a reference to the inner from the outer.
pub fn from_mut(outer: &mut Outer) -> &mut T
[src]
Get a mutable reference to the inner from the outer.
impl<T> MaybeRefUnwindSafe for T where
T: RefUnwindSafe,
[src]
T: RefUnwindSafe,
impl<T> Same<T> for T
[src]
type Output = T
Should always be Self
impl<T> SaturatedConversion for T
[src]
pub fn saturated_from<T>(t: T) -> Self where
Self: UniqueSaturatedFrom<T>,
[src]
Self: UniqueSaturatedFrom<T>,
pub fn saturated_into<T>(self) -> T where
Self: UniqueSaturatedInto<T>,
[src]
Self: UniqueSaturatedInto<T>,
impl<T, G> StorageValue<T> for G where
T: FullCodec,
G: StorageValue<T>,
[src]
T: FullCodec,
G: StorageValue<T>,
type Query = <G as StorageValue<T>>::Query
The type that get/take return.
pub fn hashed_key() -> [u8; 32]
[src]
pub fn exists() -> bool
[src]
pub fn get() -> <G as StorageValue<T>>::Query
[src]
pub fn try_get() -> Result<T, ()>
[src]
pub fn translate<O, F>(F) -> Result<Option<T>, ()> where
O: Decode,
F: FnOnce(Option<O>) -> Option<T>,
[src]
O: Decode,
F: FnOnce(Option<O>) -> Option<T>,
pub fn put<Arg>(Arg) where
Arg: EncodeLike<T>,
[src]
Arg: EncodeLike<T>,
pub fn set(<G as StorageValue<T>>::Query)
[src]
pub fn kill()
[src]
pub fn mutate<R, F>(F) -> R where
F: FnOnce(&mut <G as StorageValue<T>>::Query) -> R,
[src]
F: FnOnce(&mut <G as StorageValue<T>>::Query) -> R,
pub fn try_mutate<R, E, F>(F) -> Result<R, E> where
F: FnOnce(&mut <G as StorageValue<T>>::Query) -> Result<R, E>,
[src]
F: FnOnce(&mut <G as StorageValue<T>>::Query) -> Result<R, E>,
pub fn take() -> <G as StorageValue<T>>::Query
[src]
pub fn append<Item, EncodeLikeItem>(EncodeLikeItem) where
T: StorageAppend<Item>,
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
[src]
T: StorageAppend<Item>,
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
fn decode_len() -> Option<usize> where
T: StorageDecodeLength,
[src]
T: StorageDecodeLength,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
[src]
impl<S, T> UncheckedInto<T> for S where
T: UncheckedFrom<S>,
[src]
T: UncheckedFrom<S>,
pub fn unchecked_into(self) -> T
[src]
impl<T, S> UniqueSaturatedInto<T> for S where
T: Bounded,
S: TryInto<T>,
[src]
T: Bounded,
S: TryInto<T>,
pub fn unique_saturated_into(self) -> T
[src]
impl<V, T> VZip<V> for T where
V: MultiLane<T>,
[src]
V: MultiLane<T>,