Struct salsa::Runtime

pub struct Runtime<DB: Database> { /* private fields */ }

The salsa runtime stores the storage for all queries as well as tracking the query stack and dependencies between cycles.

Each new runtime you create (e.g., via Runtime::new or Runtime::default) will have an independent set of query storage associated with it. Normally, therefore, you only do this once, at the start of your application.

Implementations

impl<DB> Runtime<DB>where
    DB: Database,

pub fn new() -> Self

Create a new runtime; equivalent to Self::default. This is used when creating a new database.

pub fn storage(&self) -> &DB::DatabaseStorage

Returns the underlying storage, where the keys/values for all queries are kept.

pub fn snapshot(&self, from_db: &DB) -> Self

Returns a “forked” runtime, suitable for use in a forked database. “Forked” runtimes hold a read-lock on the global state, which means that any attempt to set an input will block until the forked runtime is dropped. See ParallelDatabase::snapshot for more information.

Warning. This second handle is intended to be used from a separate thread. Using two database handles from the same thread can lead to deadlock.

pub fn next_revision(&self)

Indicates that some input to the system has changed and hence that memoized values may be invalidated. This cannot be invoked while query computation is in progress.

As a user of the system, you would not normally invoke this method directly. Instead, you would use “input” queries and invoke their set method. But it can be useful if you have a “volatile” input that you must poll from time to time; in that case, you can wrap the input with a “no-storage” query and invoke this method from time to time.

pub fn sweep_all(&self, db: &DB, strategy: SweepStrategy)

Default implementation for Database::sweep_all.

pub fn id(&self) -> RuntimeId

The unique identifier attached to this SalsaRuntime. Each snapshotted runtime has a distinct identifier.

pub fn active_query(&self) -> Option<DB::QueryDescriptor>

Returns the descriptor for the query that this thread is actively executing (if any).

pub fn is_current_revision_canceled(&self) -> bool

Check if the current revision is canceled. If this method ever returns true, the currently executing query is also marked as having an untracked read – this means that, in the next revision, we will always recompute its value “as if” some input had changed. This means that, if your revision is canceled (which indicates that current query results will be ignored) your query is free to shortcircuit and return whatever it likes.

Trait Implementations

impl<DB> Debug for Runtime<DB>where
    DB: Database,

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<DB> Default for Runtime<DB>where
    DB: Database,

fn default() -> Self

Returns the “default value” for a type.