491 lines
15 KiB
Rust
491 lines
15 KiB
Rust
pub use futures::future::BoxFuture;
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pub use std::future::ready;
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use super::Assertion;
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use super::ActorId;
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use super::Handle;
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use super::schemas::internal_protocol::*;
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use super::error::Error;
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use preserves::value::Domain;
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use preserves::value::IOValue;
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use preserves::value::Map;
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use preserves::value::NestedValue;
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use std::boxed::Box;
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use std::collections::hash_map::HashMap;
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use std::sync::Arc;
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use std::sync::atomic::{AtomicUsize, Ordering};
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use tokio::select;
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use tokio::sync::mpsc::{unbounded_channel, UnboundedSender, UnboundedReceiver};
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use tokio_util::sync::CancellationToken;
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use tracing::{Instrument, trace, error};
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pub type ActorResult = Result<(), Error>;
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pub type ActorHandle = tokio::task::JoinHandle<ActorResult>;
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pub trait Entity: Send {
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fn assert(&mut self, _t: &mut Activation, _a: Assertion, _h: Handle) -> ActorResult {
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Ok(())
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}
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fn retract(&mut self, _t: &mut Activation, _h: Handle) -> ActorResult {
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Ok(())
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}
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fn message(&mut self, _t: &mut Activation, _m: Assertion) -> ActorResult {
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Ok(())
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}
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fn sync(&mut self, t: &mut Activation, peer: Arc<Ref>) -> ActorResult {
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t.message(peer, Assertion::new(true));
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Ok(())
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}
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fn turn_end(&mut self, _t: &mut Activation) -> ActorResult {
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Ok(())
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}
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fn exit_hook(&mut self, _t: &mut Activation, _exit_status: &ActorResult) -> BoxFuture<ActorResult> {
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Box::pin(ready(Ok(())))
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}
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}
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type OutboundAssertions = Map<Handle, Arc<Ref>>;
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// This is what other implementations call a "Turn", renamed here to
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// avoid conflicts with schemas::internal_protocol::Turn.
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pub struct Activation<'activation> {
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pub actor: &'activation mut Actor,
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queues: HashMap<ActorId, Vec<(Arc<Ref>, Event)>>,
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turn_end_revisit_flag: bool,
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}
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#[derive(Debug)]
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enum SystemMessage {
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Release,
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ReleaseOid(Oid),
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Turn(Turn),
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Crash(Error),
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}
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pub struct Mailbox {
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pub actor_id: ActorId,
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pub mailbox_id: u64,
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tx: UnboundedSender<SystemMessage>,
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queue_depth: Arc<AtomicUsize>,
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mailbox_count: Arc<AtomicUsize>,
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}
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pub struct Actor {
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actor_id: ActorId,
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tx: UnboundedSender<SystemMessage>,
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rx: UnboundedReceiver<SystemMessage>,
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queue_depth: Arc<AtomicUsize>,
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mailbox_count: Arc<AtomicUsize>,
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outbound_assertions: OutboundAssertions,
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oid_map: Map<Oid, Box<dyn Entity + Send>>,
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next_task_id: u64,
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linked_tasks: Map<u64, CancellationToken>,
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exit_hooks: Vec<Oid>,
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}
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#[derive(Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
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pub struct Ref {
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pub relay: Mailbox,
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pub target: Oid,
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/* TODO: attenuation */
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}
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//---------------------------------------------------------------------------
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impl<'activation> Activation<'activation> {
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pub fn for_actor(actor: &'activation mut Actor) -> Self {
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Activation {
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actor,
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queues: HashMap::new(),
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turn_end_revisit_flag: false,
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}
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}
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pub fn assert<M>(&mut self, r: Arc<Ref>, a: M) -> Handle where M: Into<Assertion> {
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let handle = crate::next_handle();
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self.queue_for(&r).push((Arc::clone(&r), Event::Assert(Box::new(
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Assert { assertion: Assertion(a.into()), handle: handle.clone() }))));
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self.actor.outbound_assertions.insert(handle.clone(), r);
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handle
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}
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pub fn retract(&mut self, handle: Handle) {
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if let Some(r) = self.actor.outbound_assertions.remove(&handle) {
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self.retract_known_ref(r, handle)
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}
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}
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pub fn retract_known_ref(&mut self, r: Arc<Ref>, handle: Handle) {
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self.queue_for(&r).push((r, Event::Retract(Box::new(Retract { handle }))));
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}
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pub fn message<M>(&mut self, r: Arc<Ref>, m: M) where M: Into<Assertion> {
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self.queue_for(&r).push((r, Event::Message(Box::new(
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Message { body: Assertion(m.into()) }))))
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}
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pub fn set_turn_end_flag(&mut self) {
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self.turn_end_revisit_flag = true;
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}
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fn queue_for(&mut self, r: &Arc<Ref>) -> &mut Vec<(Arc<Ref>, Event)> {
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self.queues.entry(r.relay.actor_id).or_default()
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}
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fn deliver(&mut self) {
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for (_actor_id, turn) in std::mem::take(&mut self.queues).into_iter() {
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if turn.len() == 0 { continue; }
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let first_ref = Arc::clone(&turn[0].0);
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let target = &first_ref.relay;
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target.send(Turn(turn.into_iter().map(
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|(r, e)| TurnEvent { oid: r.target.clone(), event: e }).collect()));
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}
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}
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fn with_oid<R,
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Ff: FnOnce(&mut Self) -> R,
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Fs: FnOnce(&mut Self, &mut Box<dyn Entity + Send>) -> R>(
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&mut self,
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oid: &Oid,
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kf: Ff,
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ks: Fs,
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) -> R {
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match self.actor.oid_map.remove_entry(&oid) {
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None => kf(self),
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Some((k, mut e)) => {
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let result = ks(self, &mut e);
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self.actor.oid_map.insert(k, e);
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result
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}
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}
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}
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}
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impl<'activation> Drop for Activation<'activation> {
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fn drop(&mut self) {
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self.deliver()
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}
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}
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impl Mailbox {
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pub fn send(&self, t: Turn) {
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let _ = self.tx.send(SystemMessage::Turn(t));
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self.queue_depth.fetch_add(1, Ordering::Relaxed);
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}
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}
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impl std::fmt::Debug for Mailbox {
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fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
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write!(f, "#<Mailbox {}:{}>", self.actor_id, self.mailbox_id)
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}
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}
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impl std::hash::Hash for Mailbox {
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fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
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self.mailbox_id.hash(state)
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}
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}
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impl Eq for Mailbox {}
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impl PartialEq for Mailbox {
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fn eq(&self, other: &Mailbox) -> bool {
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self.mailbox_id == other.mailbox_id
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}
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}
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impl Ord for Mailbox {
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fn cmp(&self, other: &Mailbox) -> std::cmp::Ordering {
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return self.mailbox_id.cmp(&other.mailbox_id)
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}
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}
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impl PartialOrd for Mailbox {
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fn partial_cmp(&self, other: &Mailbox) -> Option<std::cmp::Ordering> {
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return Some(self.cmp(&other))
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}
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}
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impl Clone for Mailbox {
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fn clone(&self) -> Self {
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let Mailbox { actor_id, tx, queue_depth, mailbox_count, .. } = self;
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let _old_refcount = mailbox_count.fetch_add(1, Ordering::SeqCst);
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let new_mailbox = Mailbox {
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actor_id: *actor_id,
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mailbox_id: crate::next_mailbox_id(),
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tx: tx.clone(),
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queue_depth: Arc::clone(queue_depth),
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mailbox_count: Arc::clone(mailbox_count),
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};
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trace!(old_mailbox = debug(&self),
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new_mailbox = debug(&new_mailbox),
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new_mailbox_refcount = debug(_old_refcount + 1));
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new_mailbox
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}
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}
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impl Drop for Mailbox {
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fn drop(&mut self) {
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let old_mailbox_refcount = self.mailbox_count.fetch_sub(1, Ordering::SeqCst);
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let new_mailbox_refcount = old_mailbox_refcount - 1;
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trace!(mailbox = debug(&self),
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new_mailbox_refcount);
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if new_mailbox_refcount == 0 {
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let _ = self.tx.send(SystemMessage::Release);
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()
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}
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}
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}
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impl Actor {
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pub fn new() -> Self {
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let (tx, rx) = unbounded_channel();
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let actor_id = crate::next_actor_id();
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trace!(id = actor_id, "Actor::new");
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Actor {
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actor_id,
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tx,
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rx,
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queue_depth: Arc::new(AtomicUsize::new(0)),
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mailbox_count: Arc::new(AtomicUsize::new(0)),
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outbound_assertions: Map::new(),
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oid_map: Map::new(),
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next_task_id: 0,
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linked_tasks: Map::new(),
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exit_hooks: Vec::new(),
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}
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}
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pub fn id(&self) -> ActorId {
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self.actor_id
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}
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fn mailbox(&mut self) -> Mailbox {
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let _old_refcount = self.mailbox_count.fetch_add(1, Ordering::SeqCst);
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let new_mailbox = Mailbox {
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actor_id: self.actor_id,
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mailbox_id: crate::next_mailbox_id(),
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tx: self.tx.clone(),
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queue_depth: Arc::clone(&self.queue_depth),
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mailbox_count: Arc::clone(&self.mailbox_count),
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};
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trace!(new_mailbox = debug(&new_mailbox),
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new_mailbox_refcount = debug(_old_refcount + 1));
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new_mailbox
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}
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pub fn shutdown(&mut self) {
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let _ = self.tx.send(SystemMessage::Release);
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()
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}
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pub fn create<E: Entity + Send + 'static>(&mut self, e: E) -> Arc<Ref> {
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let r = Ref {
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relay: self.mailbox(),
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target: crate::next_oid(),
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};
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self.oid_map.insert(r.target.clone(), Box::new(e));
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Arc::new(r)
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}
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pub fn boot<F: 'static + Send + FnOnce(&mut Self) -> BoxFuture<ActorResult>>(
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mut self,
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name: tracing::Span,
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boot: F,
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) -> ActorHandle {
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let id = self.id();
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tokio::spawn(async move {
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trace!(id, "start");
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let result = self.run(boot).await;
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{
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let mut t = Activation::for_actor(&mut self);
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for oid in std::mem::take(&mut t.actor.exit_hooks) {
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match t.actor.oid_map.remove_entry(&oid) {
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None => (),
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Some((k, mut e)) => {
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if let Err(err) = e.exit_hook(&mut t, &result).await {
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tracing::warn!(err = debug(err),
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oid = debug(oid),
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"error in exit hook");
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}
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t.actor.oid_map.insert(k, e);
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}
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}
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}
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}
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match &result {
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Ok(()) => trace!(id, "normal stop"),
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Err(e) => error!(id, "error stop: {}", e),
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}
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result
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}.instrument(name))
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}
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pub fn start(self, name: tracing::Span) -> ActorHandle {
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self.boot(name, |_ac| Box::pin(ready(Ok(()))))
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}
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async fn run<F: 'static + Send + FnOnce(&mut Self) -> BoxFuture<ActorResult>>(
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&mut self,
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boot: F,
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) -> ActorResult {
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let id = self.id();
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trace!(id, "boot");
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boot(self).await?;
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trace!(id, "run");
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loop {
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match self.rx.recv().await {
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None =>
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Err(Error {
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message: "Unexpected channel close".to_owned(),
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detail: _Any::new(false),
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})?,
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Some(m) => {
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trace!(id, m = debug(&m), "system message");
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if self.handle(m)? {
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return Ok(());
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}
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// We would have a loop calling try_recv until it answers "no more at
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// present" here, to avoid decrementing queue_depth for every message
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// (instead zeroing it on queue empty - it only needs to be approximate),
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// but try_recv has been removed from mpsc at the time of writing. See
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// https://github.com/tokio-rs/tokio/issues/3350 .
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self.queue_depth.fetch_sub(1, Ordering::Relaxed);
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}
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}
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}
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}
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pub fn add_exit_hook(&mut self, oid: &Oid) {
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self.exit_hooks.push(oid.clone())
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}
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fn handle(&mut self, m: SystemMessage) -> Result<bool, Error> {
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match m {
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SystemMessage::Release =>
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Ok(true),
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SystemMessage::ReleaseOid(oid) => {
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self.oid_map.remove(&oid);
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Ok(false)
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}
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SystemMessage::Turn(Turn(events)) => {
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let mut t = Activation::for_actor(self);
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let mut revisit_oids = Vec::new();
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for TurnEvent { oid, event } in events.into_iter() {
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t.with_oid(&oid, |_| Ok(()), |t, e| match event {
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Event::Assert(b) => {
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let Assert { assertion: Assertion(assertion), handle } = *b;
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e.assert(t, assertion, handle)
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}
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Event::Retract(b) => {
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let Retract { handle } = *b;
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e.retract(t, handle)
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}
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Event::Message(b) => {
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let Message { body: Assertion(body) } = *b;
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e.message(t, body)
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}
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Event::Sync(b) => {
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let Sync { peer } = *b;
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e.sync(t, peer)
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}
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})?;
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if t.turn_end_revisit_flag {
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t.turn_end_revisit_flag = false;
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revisit_oids.push(oid);
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}
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}
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for oid in revisit_oids {
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t.with_oid(&oid, |_| Ok(()), |t, e| e.turn_end(t))?;
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}
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Ok(false)
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}
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SystemMessage::Crash(e) =>
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Err(e)?
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}
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}
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pub fn linked_task<F: futures::Future<Output = ActorResult> + Send + 'static>(
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&mut self,
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name: tracing::Span,
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boot: F,
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) -> ActorHandle {
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let id = self.id();
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let mailbox = self.mailbox();
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let token = CancellationToken::new();
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let task_id = self.next_task_id;
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self.next_task_id += 1;
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let handle = {
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let token = token.clone();
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tokio::spawn(async move {
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trace!(id, task_id, "linked task start");
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select! {
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_ = token.cancelled() => {
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trace!(id, task_id, "linked task cancelled");
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Ok(())
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}
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result = boot => {
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match &result {
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Ok(()) => trace!(id, task_id, "linked task normal stop"),
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Err(e) => {
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error!(id, task_id, "linked task error: {}", e);
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let _ = mailbox.tx.send(SystemMessage::Crash(e.clone()));
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()
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}
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}
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result
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}
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}
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}.instrument(name))
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};
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self.linked_tasks.insert(task_id, token);
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handle
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}
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}
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impl Drop for Actor {
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fn drop(&mut self) {
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for (_task_id, token) in std::mem::take(&mut self.linked_tasks).into_iter() {
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token.cancel();
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}
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let to_clear = std::mem::take(&mut self.outbound_assertions);
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let mut t = Activation::for_actor(self);
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for (handle, r) in to_clear.into_iter() {
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t.retract_known_ref(r, handle);
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}
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}
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}
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impl Ref {
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pub fn external_event(&self, event: Event) {
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self.relay.send(Turn(vec![TurnEvent { oid: self.target.clone(), event }]))
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}
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}
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impl Drop for Ref {
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fn drop(&mut self) {
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let _ = self.relay.tx.send(SystemMessage::ReleaseOid(self.target.clone()));
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()
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}
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}
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impl Domain for Ref {}
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impl std::convert::TryFrom<&IOValue> for Ref {
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type Error = preserves_schema::support::ParseError;
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fn try_from(_v: &IOValue) -> Result<Self, Self::Error> {
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panic!("Attempted to serialize Ref via IOValue");
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}
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}
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impl std::convert::From<&Ref> for IOValue {
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fn from(_v: &Ref) -> IOValue {
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panic!("Attempted to deserialize Ref via IOValue");
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}
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}
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