Struct Db

pub struct Db<Storage> { /* private fields */ }

The central database object to manage and cache incremental computations.

To use this, a type implementing Storage is required to be provided. See the documentation for impl_storage!.

Implementations

impl<Storage: Default> Db<Storage>

pub fn new() -> Self

Construct a new Db object using Default::default() for the initial storage.

impl<S> Db<S>

pub fn with_storage(storage: S) -> Self

Construct a new Db object with the given initial storage.

pub fn storage(&self) -> &S

Retrieve an immutable reference to this Db’s storage

pub fn storage_mut(&mut self) -> &mut S

Retrieve a mutable reference to this Db’s storage.

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

impl<S: Storage> Db<S>

pub fn is_stale<C: OutputType>(&self, input: &C) -> bool

where S: StorageFor<C>,

True if a given input is stale and needs to be re-computed. Inputs which have never been computed are also considered stale.

This does not actually re-compute the input.

pub fn update_input<C>(&mut self, input: C, new_value: C::Output)

where C: Debug + ComputationId + OutputType, S: StorageFor<C>,

Updates an input with a new value

Panics in debug mode if the input is not an input - ie. it has at least 1 dependency. Note that this check is skipped when compiling in Release mode.

pub fn get<C: OutputType + ComputationId>(&mut self, compute: C) -> &C::Output

where S: StorageFor<C>,

Retrieves the up to date value for the given computation, re-running any dependencies as necessary.

This function can panic if the dynamic type of the value returned by compute.run(..) is not T.

Trait Implementations

impl<S: Default> Default for Db<S>

fn default() -> Self

Returns the “default value” for a type.

impl<'de, Storage> Deserialize<'de> for Db<Storage>

where Storage: Deserialize<'de>,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<Storage> Serialize for Db<Storage>

where Storage: Serialize,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.