Struct frame_support::storage::types::StorageValue
source · pub struct StorageValue<Prefix, Value, QueryKind = OptionQuery, OnEmpty = GetDefault>(_);
Expand description
A type that allow to store a value.
Each value is stored at:
Twox128(Prefix::pallet_prefix()) ++ Twox128(Prefix::STORAGE_PREFIX)
Implementations§
source§impl<Prefix, Value, QueryKind, OnEmpty> StorageValue<Prefix, Value, QueryKind, OnEmpty>where
Prefix: StorageInstance,
Value: FullCodec,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
impl<Prefix, Value, QueryKind, OnEmpty> StorageValue<Prefix, Value, QueryKind, OnEmpty>where Prefix: StorageInstance, Value: FullCodec, QueryKind: QueryKindTrait<Value, OnEmpty>, OnEmpty: Get<QueryKind::Query> + 'static,
sourcepub fn hashed_key() -> [u8; 32]
pub fn hashed_key() -> [u8; 32]
Get the storage key.
sourcepub fn try_get() -> Result<Value, ()>
pub fn try_get() -> Result<Value, ()>
Try to get the underlying value from the provided storage instance; Ok
if it exists,
Err
if not.
sourcepub fn translate<O: Decode, F: FnOnce(Option<O>) -> Option<Value>>(
f: F
) -> Result<Option<Value>, ()>
pub fn translate<O: Decode, F: FnOnce(Option<O>) -> Option<Value>>( 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).
sourcepub fn put<Arg: EncodeLike<Value>>(val: Arg)
pub fn put<Arg: EncodeLike<Value>>(val: Arg)
Store a value under this key into the provided storage instance.
sourcepub fn set(val: QueryKind::Query)
pub fn set(val: QueryKind::Query)
Store a value under this key into the provided storage instance.
this uses the query type rather than the underlying value.
sourcepub fn mutate_extant<R: Default, F: FnOnce(&mut Value) -> R>(f: F) -> R
pub fn mutate_extant<R: Default, F: FnOnce(&mut Value) -> R>(f: F) -> R
Mutate the value under a key iff it exists. Do nothing and return the default value if not.
sourcepub fn try_mutate<R, E, F: FnOnce(&mut QueryKind::Query) -> Result<R, E>>(
f: F
) -> Result<R, E>
pub fn try_mutate<R, E, F: FnOnce(&mut QueryKind::Query) -> Result<R, E>>( f: F ) -> Result<R, E>
Mutate the value if closure returns Ok
sourcepub fn mutate_exists<R, F: FnOnce(&mut Option<Value>) -> R>(f: F) -> R
pub fn mutate_exists<R, F: FnOnce(&mut Option<Value>) -> R>(f: F) -> R
Mutate the value. Deletes the item if mutated to a None
.
sourcepub fn try_mutate_exists<R, E, F: FnOnce(&mut Option<Value>) -> Result<R, E>>(
f: F
) -> Result<R, E>
pub fn try_mutate_exists<R, E, F: FnOnce(&mut Option<Value>) -> Result<R, E>>( f: F ) -> Result<R, E>
Mutate the value if closure returns Ok
. Deletes the item if mutated to a None
.
sourcepub fn append<Item, EncodeLikeItem>(item: EncodeLikeItem)where
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
Value: StorageAppend<Item>,
pub fn append<Item, EncodeLikeItem>(item: EncodeLikeItem)where 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.
sourcepub fn decode_len() -> Option<usize>where
Value: StorageDecodeLength,
pub fn decode_len() -> Option<usize>where 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.
sourcepub fn try_append<Item, EncodeLikeItem>(item: EncodeLikeItem) -> Result<(), ()>where
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
Value: StorageTryAppend<Item>,
pub fn try_append<Item, EncodeLikeItem>(item: EncodeLikeItem) -> Result<(), ()>where Item: Encode, EncodeLikeItem: EncodeLike<Item>, Value: StorageTryAppend<Item>,
Try and append the given item to the value in the storage.
Is only available if Value
of the storage implements StorageTryAppend
.
Trait Implementations§
source§impl<Prefix, Value, QueryKind, OnEmpty> PartialStorageInfoTrait for StorageValue<Prefix, Value, QueryKind, OnEmpty>where
Prefix: StorageInstance,
Value: FullCodec,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
impl<Prefix, Value, QueryKind, OnEmpty> PartialStorageInfoTrait for StorageValue<Prefix, Value, QueryKind, OnEmpty>where Prefix: StorageInstance, Value: FullCodec, QueryKind: QueryKindTrait<Value, OnEmpty>, OnEmpty: Get<QueryKind::Query> + 'static,
It doesn’t require to implement MaxEncodedLen
and give no information for max_size
.
fn partial_storage_info() -> Vec<StorageInfo>
source§impl<Prefix, Value, QueryKind, OnEmpty> StorageEntryMetadataBuilder for StorageValue<Prefix, Value, QueryKind, OnEmpty>where
Prefix: StorageInstance,
Value: FullCodec + StaticTypeInfo,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
impl<Prefix, Value, QueryKind, OnEmpty> StorageEntryMetadataBuilder for StorageValue<Prefix, Value, QueryKind, OnEmpty>where Prefix: StorageInstance, Value: FullCodec + StaticTypeInfo, QueryKind: QueryKindTrait<Value, OnEmpty>, OnEmpty: Get<QueryKind::Query> + 'static,
source§fn build_metadata(
docs: Vec<&'static str>,
entries: &mut Vec<StorageEntryMetadataIR>
)
fn build_metadata( docs: Vec<&'static str>, entries: &mut Vec<StorageEntryMetadataIR> )
entries
the storage metadata entries of a storage given some docs
.source§impl<Prefix, Value, QueryKind, OnEmpty> StorageInfoTrait for StorageValue<Prefix, Value, QueryKind, OnEmpty>where
Prefix: StorageInstance,
Value: FullCodec + MaxEncodedLen,
QueryKind: QueryKindTrait<Value, OnEmpty>,
OnEmpty: Get<QueryKind::Query> + 'static,
impl<Prefix, Value, QueryKind, OnEmpty> StorageInfoTrait for StorageValue<Prefix, Value, QueryKind, OnEmpty>where Prefix: StorageInstance, Value: FullCodec + MaxEncodedLen, QueryKind: QueryKindTrait<Value, OnEmpty>, OnEmpty: Get<QueryKind::Query> + 'static,
fn storage_info() -> Vec<StorageInfo>
Auto Trait Implementations§
impl<Prefix, Value, QueryKind, OnEmpty> RefUnwindSafe for StorageValue<Prefix, Value, QueryKind, OnEmpty>where 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,
impl<Prefix, Value, QueryKind, OnEmpty> Sync for StorageValue<Prefix, Value, QueryKind, OnEmpty>where 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,
impl<Prefix, Value, QueryKind, OnEmpty> UnwindSafe for StorageValue<Prefix, Value, QueryKind, OnEmpty>where OnEmpty: UnwindSafe, Prefix: UnwindSafe, QueryKind: UnwindSafe, Value: UnwindSafe,
Blanket Implementations§
source§impl<T> CheckedConversion for T
impl<T> CheckedConversion for T
source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T, Outer> IsWrappedBy<Outer> for Twhere
Outer: AsRef<T> + AsMut<T> + From<T>,
T: From<Outer>,
impl<T, Outer> IsWrappedBy<Outer> for Twhere Outer: AsRef<T> + AsMut<T> + From<T>, T: From<Outer>,
§impl<T> Pointable for T
impl<T> Pointable for T
source§impl<T> SaturatedConversion for T
impl<T> SaturatedConversion for T
source§fn saturated_from<T>(t: T) -> Selfwhere
Self: UniqueSaturatedFrom<T>,
fn saturated_from<T>(t: T) -> Selfwhere Self: UniqueSaturatedFrom<T>,
source§fn saturated_into<T>(self) -> Twhere
Self: UniqueSaturatedInto<T>,
fn saturated_into<T>(self) -> Twhere Self: UniqueSaturatedInto<T>,
T
. Read moresource§impl<T, G> StorageValue<T> for Gwhere
T: FullCodec,
G: StorageValue<T>,
impl<T, G> StorageValue<T> for Gwhere T: FullCodec, G: StorageValue<T>,
source§fn hashed_key() -> [u8; 32]
fn hashed_key() -> [u8; 32]
source§fn get() -> <G as StorageValue<T>>::Query
fn get() -> <G as StorageValue<T>>::Query
source§fn try_get() -> Result<T, ()>
fn try_get() -> Result<T, ()>
source§fn translate<O, F>(f: F) -> Result<Option<T>, ()>where
O: Decode,
F: FnOnce(Option<O>) -> Option<T>,
fn translate<O, F>(f: F) -> Result<Option<T>, ()>where O: Decode, F: FnOnce(Option<O>) -> Option<T>,
O
) to the current type. Read moresource§fn put<Arg>(val: Arg)where
Arg: EncodeLike<T>,
fn put<Arg>(val: Arg)where Arg: EncodeLike<T>,
source§fn set(maybe_val: <G as StorageValue<T>>::Query)
fn set(maybe_val: <G as StorageValue<T>>::Query)
source§fn mutate<R, F>(f: F) -> Rwhere
F: FnOnce(&mut <G as StorageValue<T>>::Query) -> R,
fn mutate<R, F>(f: F) -> Rwhere F: FnOnce(&mut <G as StorageValue<T>>::Query) -> R,
source§fn try_mutate<R, E, F>(f: F) -> Result<R, E>where
F: FnOnce(&mut <G as StorageValue<T>>::Query) -> Result<R, E>,
fn try_mutate<R, E, F>(f: F) -> Result<R, E>where F: FnOnce(&mut <G as StorageValue<T>>::Query) -> Result<R, E>,
Ok
source§fn mutate_exists<R, F>(f: F) -> Rwhere
F: FnOnce(&mut Option<T>) -> R,
fn mutate_exists<R, F>(f: F) -> Rwhere F: FnOnce(&mut Option<T>) -> R,
None
.source§fn try_mutate_exists<R, E, F>(f: F) -> Result<R, E>where
F: FnOnce(&mut Option<T>) -> Result<R, E>,
fn try_mutate_exists<R, E, F>(f: F) -> Result<R, E>where F: FnOnce(&mut Option<T>) -> Result<R, E>,
Ok
. Deletes the item if mutated to a None
.source§fn append<Item, EncodeLikeItem>(item: EncodeLikeItem)where
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
T: StorageAppend<Item>,
fn append<Item, EncodeLikeItem>(item: EncodeLikeItem)where Item: Encode, EncodeLikeItem: EncodeLike<Item>, T: StorageAppend<Item>,
source§fn mutate_extant<R: Default, F: FnOnce(&mut T) -> R>(f: F) -> R
fn mutate_extant<R: Default, F: FnOnce(&mut T) -> R>(f: F) -> R
source§fn decode_len() -> Option<usize>where
T: StorageDecodeLength,
fn decode_len() -> Option<usize>where T: StorageDecodeLength,
source§impl<T, I, StorageValueT> TryAppendValue<T, I> for StorageValueTwhere
I: Encode,
T: FullCodec + StorageTryAppend<I>,
StorageValueT: StorageValue<T>,
impl<T, I, StorageValueT> TryAppendValue<T, I> for StorageValueTwhere I: Encode, T: FullCodec + StorageTryAppend<I>, StorageValueT: StorageValue<T>,
source§fn try_append<LikeI>(item: LikeI) -> Result<(), ()>where
LikeI: EncodeLike<I>,
fn try_append<LikeI>(item: LikeI) -> Result<(), ()>where LikeI: EncodeLike<I>,
item
into the storage item. Read moresource§impl<S, T> UncheckedInto<T> for Swhere
T: UncheckedFrom<S>,
impl<S, T> UncheckedInto<T> for Swhere T: UncheckedFrom<S>,
source§fn unchecked_into(self) -> T
fn unchecked_into(self) -> T
unchecked_from
.source§impl<T, S> UniqueSaturatedInto<T> for Swhere
T: Bounded,
S: TryInto<T>,
impl<T, S> UniqueSaturatedInto<T> for Swhere T: Bounded, S: TryInto<T>,
source§fn unique_saturated_into(self) -> T
fn unique_saturated_into(self) -> T
T
.