pub trait StorageMap<K: FullEncode, V: FullCodec> {
type Query;
Show 19 methods
// Required methods
fn hashed_key_for<KeyArg: EncodeLike<K>>(key: KeyArg) -> Vec<u8> ⓘ;
fn contains_key<KeyArg: EncodeLike<K>>(key: KeyArg) -> bool;
fn get<KeyArg: EncodeLike<K>>(key: KeyArg) -> Self::Query;
fn set<KeyArg: EncodeLike<K>>(key: KeyArg, query: Self::Query);
fn try_get<KeyArg: EncodeLike<K>>(key: KeyArg) -> Result<V, ()>;
fn swap<KeyArg1: EncodeLike<K>, KeyArg2: EncodeLike<K>>(
key1: KeyArg1,
key2: KeyArg2,
);
fn insert<KeyArg: EncodeLike<K>, ValArg: EncodeLike<V>>(
key: KeyArg,
val: ValArg,
);
fn remove<KeyArg: EncodeLike<K>>(key: KeyArg);
fn mutate<KeyArg: EncodeLike<K>, R, F: FnOnce(&mut Self::Query) -> R>(
key: KeyArg,
f: F,
) -> R;
fn try_mutate<KeyArg: EncodeLike<K>, R, E, F: FnOnce(&mut Self::Query) -> Result<R, E>>(
key: KeyArg,
f: F,
) -> Result<R, E>;
fn mutate_exists<KeyArg: EncodeLike<K>, R, F: FnOnce(&mut Option<V>) -> R>(
key: KeyArg,
f: F,
) -> R;
fn try_mutate_exists<KeyArg: EncodeLike<K>, R, E, F: FnOnce(&mut Option<V>) -> Result<R, E>>(
key: KeyArg,
f: F,
) -> Result<R, E>;
fn take<KeyArg: EncodeLike<K>>(key: KeyArg) -> Self::Query;
fn append<Item, EncodeLikeItem, EncodeLikeKey>(
key: EncodeLikeKey,
item: EncodeLikeItem,
)
where EncodeLikeKey: EncodeLike<K>,
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
V: StorageAppend<Item>;
fn migrate_key<OldHasher: StorageHasher, KeyArg: EncodeLike<K>>(
key: KeyArg,
) -> Option<V>;
// Provided methods
fn mutate_extant<KeyArg: EncodeLike<K>, R: Default, F: FnOnce(&mut V) -> R>(
key: KeyArg,
f: F,
) -> R { ... }
fn decode_len<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<usize>
where V: StorageDecodeLength { ... }
fn decode_non_dedup_len<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<usize>
where V: StorageDecodeNonDedupLength { ... }
fn migrate_key_from_blake<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<V> { ... }
}
Expand description
A strongly-typed map in storage.
Details on implementation can be found at [generator::StorageMap
].
Required Associated Types§
Required Methods§
Sourcefn hashed_key_for<KeyArg: EncodeLike<K>>(key: KeyArg) -> Vec<u8> ⓘ
fn hashed_key_for<KeyArg: EncodeLike<K>>(key: KeyArg) -> Vec<u8> ⓘ
Get the storage key used to fetch a value corresponding to a specific key.
Sourcefn contains_key<KeyArg: EncodeLike<K>>(key: KeyArg) -> bool
fn contains_key<KeyArg: EncodeLike<K>>(key: KeyArg) -> bool
Does the value (explicitly) exist in storage?
Sourcefn get<KeyArg: EncodeLike<K>>(key: KeyArg) -> Self::Query
fn get<KeyArg: EncodeLike<K>>(key: KeyArg) -> Self::Query
Load the value associated with the given key from the map.
Sourcefn set<KeyArg: EncodeLike<K>>(key: KeyArg, query: Self::Query)
fn set<KeyArg: EncodeLike<K>>(key: KeyArg, query: Self::Query)
Store or remove the value to be associated with key
so that get
returns the query
.
Sourcefn try_get<KeyArg: EncodeLike<K>>(key: KeyArg) -> Result<V, ()>
fn try_get<KeyArg: EncodeLike<K>>(key: KeyArg) -> Result<V, ()>
Try to get the value for the given key from the map.
Returns Ok
if it exists, Err
if not.
Sourcefn swap<KeyArg1: EncodeLike<K>, KeyArg2: EncodeLike<K>>(
key1: KeyArg1,
key2: KeyArg2,
)
fn swap<KeyArg1: EncodeLike<K>, KeyArg2: EncodeLike<K>>( key1: KeyArg1, key2: KeyArg2, )
Swap the values of two keys.
Sourcefn insert<KeyArg: EncodeLike<K>, ValArg: EncodeLike<V>>(
key: KeyArg,
val: ValArg,
)
fn insert<KeyArg: EncodeLike<K>, ValArg: EncodeLike<V>>( key: KeyArg, val: ValArg, )
Store a value to be associated with the given key from the map.
Sourcefn mutate<KeyArg: EncodeLike<K>, R, F: FnOnce(&mut Self::Query) -> R>(
key: KeyArg,
f: F,
) -> R
fn mutate<KeyArg: EncodeLike<K>, R, F: FnOnce(&mut Self::Query) -> R>( key: KeyArg, f: F, ) -> R
Mutate the value under a key.
Sourcefn try_mutate<KeyArg: EncodeLike<K>, R, E, F: FnOnce(&mut Self::Query) -> Result<R, E>>(
key: KeyArg,
f: F,
) -> Result<R, E>
fn try_mutate<KeyArg: EncodeLike<K>, R, E, F: FnOnce(&mut Self::Query) -> Result<R, E>>( key: KeyArg, f: F, ) -> Result<R, E>
Mutate the item, only if an Ok
value is returned.
Sourcefn mutate_exists<KeyArg: EncodeLike<K>, R, F: FnOnce(&mut Option<V>) -> R>(
key: KeyArg,
f: F,
) -> R
fn mutate_exists<KeyArg: EncodeLike<K>, R, F: FnOnce(&mut Option<V>) -> R>( key: KeyArg, f: F, ) -> R
Mutate the value under a key.
Deletes the item if mutated to a None
.
Sourcefn try_mutate_exists<KeyArg: EncodeLike<K>, R, E, F: FnOnce(&mut Option<V>) -> Result<R, E>>(
key: KeyArg,
f: F,
) -> Result<R, E>
fn try_mutate_exists<KeyArg: EncodeLike<K>, R, E, F: FnOnce(&mut Option<V>) -> Result<R, E>>( key: KeyArg, f: F, ) -> Result<R, E>
Mutate the item, only if an Ok
value is returned. Deletes the item if mutated to a None
.
f
will always be called with an option representing if the storage item exists (Some<V>
)
or if the storage item does not exist (None
), independent of the QueryType
.
Sourcefn append<Item, EncodeLikeItem, EncodeLikeKey>(
key: EncodeLikeKey,
item: EncodeLikeItem,
)where
EncodeLikeKey: EncodeLike<K>,
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
V: StorageAppend<Item>,
fn append<Item, EncodeLikeItem, EncodeLikeKey>(
key: EncodeLikeKey,
item: EncodeLikeItem,
)where
EncodeLikeKey: EncodeLike<K>,
Item: Encode,
EncodeLikeItem: EncodeLike<Item>,
V: StorageAppend<Item>,
Append the given items to the value in the storage.
V
is required to implement codec::EncodeAppend
.
§Warning
If the storage item is not encoded properly, the storage will be overwritten
and set to [item]
. Any default value set for the storage item will be ignored
on overwrite.
Sourcefn migrate_key<OldHasher: StorageHasher, KeyArg: EncodeLike<K>>(
key: KeyArg,
) -> Option<V>
fn migrate_key<OldHasher: StorageHasher, KeyArg: EncodeLike<K>>( key: KeyArg, ) -> Option<V>
Migrate an item with the given key
from a defunct OldHasher
to the current hasher.
If the key doesn’t exist, then it’s a no-op. If it does, then it returns its value.
Provided Methods§
Sourcefn mutate_extant<KeyArg: EncodeLike<K>, R: Default, F: FnOnce(&mut V) -> R>(
key: KeyArg,
f: F,
) -> R
fn mutate_extant<KeyArg: EncodeLike<K>, R: Default, F: FnOnce(&mut V) -> R>( key: KeyArg, f: F, ) -> R
Mutate the value under a key if the value already exists. Do nothing and return the default value if not.
Sourcefn decode_len<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<usize>where
V: StorageDecodeLength,
fn decode_len<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<usize>where
V: StorageDecodeLength,
Read the length of the storage value without decoding the entire value under the
given key
.
V
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 completely
ignored by this function.
Sourcefn decode_non_dedup_len<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<usize>where
V: StorageDecodeNonDedupLength,
fn decode_non_dedup_len<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<usize>where
V: StorageDecodeNonDedupLength,
Read the length of the storage value without decoding the entire value.
V
is required to implement StorageDecodeNonDedupLength
.
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 thatget()
does not return a value. The default value is completely ignored by this function. -
The value returned is the non-deduplicated length of the underlying Vector in storage.This means that any duplicate items are included.
Sourcefn migrate_key_from_blake<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<V>
fn migrate_key_from_blake<KeyArg: EncodeLike<K>>(key: KeyArg) -> Option<V>
Migrate an item with the given key
from a blake2_256
hasher to the current hasher.
If the key doesn’t exist, then it’s a no-op. If it does, then it returns its value.
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.