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use super::*;
impl HostState {
/// Returns true once shutdown has drained persistence and the host loop may
/// stop.
pub(super) async fn handle(&mut self, event: HostEvent) -> bool {
match event {
HostEvent::View {
session_id,
snapshot,
prompt_driven,
} => self.observe(session_id, snapshot, prompt_driven).await,
HostEvent::Retain { live } => self.retain_sessions(&live),
HostEvent::Start {
session_id,
manual,
reply,
} => self.begin(session_id, manual, reply),
HostEvent::Prepared {
session_id,
manual,
reply,
prepared,
} => self.prepared(session_id, manual, reply, prepared),
HostEvent::RecoveryPrepared {
session_id,
prepared,
} => self.recovery_prepared(session_id, prepared),
HostEvent::StateSaved {
session_id,
completion,
result,
} => self.state_saved(session_id, completion, result),
HostEvent::Resolve {
session_id,
resolution,
reply,
} => {
let answer = self.resolve(&session_id, resolution);
let _ = reply.send(answer);
}
HostEvent::Step {
session_id,
epoch,
step,
} => self.step(session_id, epoch, step),
HostEvent::Interrupted { interrupted } => {
for session_id in interrupted {
self.recovery_candidates.insert(session_id.clone());
if self.sessions.get(&session_id).is_some_and(|watch| {
matches!(watch.execution, MaterializedExecutionState::Idle)
}) {
self.begin_recovery(&session_id);
}
}
}
HostEvent::Shutdown { reply } => {
let result = self.shutdown().await;
let _ = reply.send(result);
return true;
}
}
false
}
/// Applies one asynchronous result to the review that asked for it.
pub(super) fn step(&mut self, session_id: String, epoch: u64, step: ReviewStep) {
// A result from a review that has since been cancelled, resolved, or
// replaced is not this review's business.
if self.reviews.get(&session_id).map(|slot| slot.epoch) != Some(epoch) {
return;
}
match step {
ReviewStep::Delta(result) => {
let requests = match result {
Ok(deltas) => self
.reviews
.get_mut(&session_id)
.map(|slot| slot.driver.delta_captured(deltas))
.unwrap_or_default(),
Err(error) => {
self.fail(
&session_id,
format!("the change could not be captured: {error}"),
);
return;
}
};
self.run(&session_id, requests);
}
ReviewStep::RoleStarted { role, result } => {
let requests = match self.reviews.get_mut(&session_id) {
Some(slot) => match result {
Ok(()) => slot.driver.role_started(&role),
Err(error)
if matches!(
slot.driver.phase(),
TurnReviewPhase::Forwarding { .. }
) =>
{
tracing::debug!(
session_id = %session_id,
role = %role,
%error,
"ignoring a late reviewer start result during primary handoff"
);
return;
}
Err(error) => {
self.fail(&session_id, error);
return;
}
},
None => return,
};
self.run(&session_id, requests);
}
ReviewStep::RolePrompted { role, result } => {
if let Err(error) = result {
if self.reviews.get(&session_id).is_some_and(|slot| {
matches!(slot.driver.phase(), TurnReviewPhase::Forwarding { .. })
}) {
// Role cleanup can report after the primary handoff
// has begun. It is unrelated to that handoff and must
// not release its prompt hold or replace its findings.
tracing::debug!(
session_id = %session_id,
role = %role,
%error,
"ignoring a late reviewer-role result during primary handoff"
);
return;
}
self.fail(
&session_id,
format!("reviewing role {role:?} could not be prompted: {error}"),
);
}
}
ReviewStep::PrimaryPrompted(result) => {
let requests = match result {
Ok(()) => self
.reviews
.get_mut(&session_id)
.map(|slot| slot.driver.forward_succeeded())
.unwrap_or_default(),
Err(error) => self
.reviews
.get_mut(&session_id)
.map(|slot| slot.driver.forward_failed(error))
.unwrap_or_default(),
};
self.run(&session_id, requests);
}
ReviewStep::RoleEvents { role, result } => self.role_events(session_id, role, result),
}
}
/// Release the retained last-view for every session no longer in the live
/// set, so a stopped or destroyed session's `MaterializedSession` (its full
/// transcript) does not linger. The in-flight review state in `reviews`/
/// `closing` is separate and keeps its own lifetime.
pub(super) fn retain_sessions(&mut self, live: &std::collections::BTreeSet<String>) {
self.sessions
.retain(|session_id, _| live.contains(session_id));
}
}