Struct polkadot_node_subsystem_util::rolling_session_window::RollingSessionWindow

pub struct RollingSessionWindow { /* private fields */ }

A rolling window of sessions and cached session info.

Implementations

impl RollingSessionWindow

pub async fn new<Sender>( sender: Sender, block_hash: Hash, db_params: DatabaseParams ) -> Result<Self, SessionsUnavailable>where Sender: SubsystemSender<RuntimeApiMessage> + SubsystemSender<ChainApiMessage>,

Initialize a new session info cache with the given window size. Invariant: The database always contains the earliest session. Then, we can always extend the session info vector using chain state.

pub fn with_session_info( earliest_session: SessionIndex, session_info: Vec<SessionInfo> ) -> Self

Initialize a new session info cache with the given window size and initial data. This is only used in approval voting tests.

pub fn session_info(&self, index: SessionIndex) -> Option<&SessionInfo>

Access the session info for the given session index, if stored within the window.

pub fn earliest_session(&self) -> SessionIndex

Access the index of the earliest session.

pub fn latest_session(&self) -> SessionIndex

Access the index of the latest session.

pub fn contains(&self, session_index: SessionIndex) -> bool

Returns true if session_index is contained in the window.

pub async fn cache_session_info_for_head<Sender>( &mut self, sender: &mut Sender, block_hash: Hash ) -> Result<SessionWindowUpdate, SessionsUnavailable>where Sender: SubsystemSender<RuntimeApiMessage> + SubsystemSender<ChainApiMessage>,

When inspecting a new import notification, updates the session info cache to match the session of the imported block’s child.

this only needs to be called on heads where we are directly notified about import, as sessions do not change often and import notifications are expected to be typically increasing in session number.

some backwards drift in session index is acceptable.