Struct DbHandle 

pub struct DbHandle<'db, S> { /* private fields */ }

A handle to the database during some operation.

This wraps calls to the Db so that any get calls will be automatically registered as dependencies of the current operation.

Implementations

impl<'db, S> DbHandle<'db, S>

pub fn storage(&self) -> &S

Retrieve an immutable reference to this Db’s storage

Note that any mutations made to the storage using this are not tracked by the database! Using this incorrectly may break correctness!

impl<S: Storage> DbHandle<'_, S>

pub fn get<C: Computation>(&self, compute: C) -> C::Output

where S: StorageFor<C>,

Locking behavior: This function locks the cell corresponding to the given computation. This can cause a deadlock if the computation recursively depends on itself.

pub fn accumulate<Item>(&self, item: Item)

where S: Accumulate<Item>,

Accumulate an item in the current computation. This item can be retrieved along with all other accumulated items in this computation and its dependencies via a call to get_accumulated.

This is most often used for operations like pushing diagnostics or logs.

pub fn get_accumulated<Item, C>(&self, compute: C) -> Vec<Item>

where C: Computation, Item: 'static, S: StorageFor<Accumulated<Item>> + StorageFor<C> + Accumulate<Item>,

Retrieve an accumulated value in a container of the user’s choice. This will return all the accumulated items after the given computation.

This is most often used for operations like retrieving diagnostics or logs.

Trait Implementations

impl<'db, S, C> DbGet<C> for DbHandle<'db, S>

where C: Computation, S: Storage + StorageFor<C>,

fn get(&self, key: C) -> C::Output

Run an incremental computation C and return its output. If C is already cached, no computation will be performed.