Struct mz_stash::TypedCollection

pub struct TypedCollection<K, V> { /* private fields */ }

A helper struct to prevent mistyping of a StashCollection’s name and k,v types.

Implementations

impl<K, V> TypedCollection<K, V>

where K: Data, V: Data,

pub async fn migrate_to<K2, V2>( &self, tx: &Transaction<'_>, f: impl for<'a> FnOnce(&'a BTreeMap<K, V>) -> Vec<MigrationAction<K, K2, V2>> ) -> Result<(), StashError>

where K2: Data, V2: Data,

Provided a closure, will migrate a TypedCollection of types K and V to types K2 and V2.

pub async fn initialize( &self, tx: &Transaction<'_>, values: impl IntoIterator<Item = (K, V)> ) -> Result<(), StashError>

Initializes a TypedCollection with the values provided in values.

Panics

• If the TypedCollection is not empty.

impl<K, V> TypedCollection<K, V>

pub const fn new(name: &'static str) -> Self

Creates a new TypedCollection with name.

pub const fn name(&self) -> &'static str

Returns the name of this TypedCollection.

impl<K, V> TypedCollection<K, V>

where K: Data, V: Data,

pub async fn from_tx( &self, tx: &Transaction<'_> ) -> Result<StashCollection<K, V>, StashError>

Returns a StashCollection corresponding to this TypedCollection.

pub async fn iter( &self, stash: &mut Stash ) -> Result<Vec<((K, V), Timestamp, Diff)>, StashError>

Returns all ((key, value), timestamp, diff) tuples in this TypedCollection.

pub async fn peek_one( &self, stash: &mut Stash ) -> Result<BTreeMap<K, V>, StashError>

Returns all key, value pairs in this TypedCollection.

pub async fn peek_key_one( &self, stash: &mut Stash, key: K ) -> Result<Option<V>, StashError>

where K: 'static,

Returns the value of key in this TypedCollection.

pub async fn insert_key_without_overwrite( &self, stash: &mut Stash, key: K, value: V ) -> Result<V, StashError>

where K: 'static, V: Clone + 'static,

Sets the given k,v pair, if not already set.

Returns the new value stored in stash after this operations.

pub async fn insert_without_overwrite<I>( &self, stash: &mut Stash, entries: I ) -> Result<BTreeMap<K, V>, StashError>

where I: IntoIterator<Item = (K, V)>, K: Clone + 'static, V: Clone + 'static,

Sets the given key value pairs, if not already set. If a new key appears multiple times in entries, its value will be from the first occurrence in entries.

Returns the new state of the collection after this operation.

pub async fn upsert_key<F, R>( &self, stash: &mut Stash, key: K, f: F ) -> Result<Result<(Option<V>, V), R>, StashError>

where F: FnOnce(Option<&V>) -> Result<V, R> + Clone + Send + Sync + 'static, K: 'static,

Sets a value for a key to the result of f. f is passed the previous value, if any.

Returns the previous value if one existed and the value returned from f.

pub async fn upsert<I>( &self, stash: &mut Stash, entries: I ) -> Result<(), StashError>

where I: IntoIterator<Item = (K, V)>, K: 'static, V: 'static,

Sets the given key value pairs, removing existing entries match any key.

pub async fn delete_keys( &self, stash: &mut Stash, keys: BTreeSet<K> ) -> Result<(), StashError>

where K: Clone + 'static, V: Clone,

Transactionally deletes any kv pair from self whose key is in keys.

Note that:

• Unlike delete, this operation operates in time O(keys), and not O(set), however does so by parallelizing a number of point queries so is likely not performant for more than 10-or-so keys.
• This operation runs in a single transaction and cannot be combined with other transactions.