99 lines
3.1 KiB
Rust
99 lines
3.1 KiB
Rust
//! Implements a [*dataspace*][crate::dataspace#GarnockJones2017]
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//! entity.
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//!
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//! **References.**
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//!
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//! - Garnock-Jones, Tony. <a name="GarnockJones2017">“Conversational
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//! Concurrency.”</a> PhD, Northeastern University, 2017. [Available
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//! on the web](https://syndicate-lang.org/tonyg-dissertation/).
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//! [PDF](https://syndicate-lang.org/papers/conversational-concurrency-201712310922.pdf).
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use super::language;
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use super::skeleton;
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use super::actor::*;
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use super::schemas::dataspace::*;
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use preserves::value::Map;
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use preserves_schema::Codec;
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/// A Dataspace object (entity).
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#[derive(Debug)]
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pub struct Dataspace {
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pub name: Name,
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/// Index over assertions placed in the dataspace; used to
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/// efficiently route assertion changes and messages to observers.
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pub index: skeleton::Index,
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/// Local memory of assertions indexed by `Handle`, used to remove
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/// assertions from the `index` when they are retracted.
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pub handle_map: Map<Handle, _Any>,
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}
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impl Dataspace {
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/// Construct a new, empty dataspace.
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pub fn new(name: Name) -> Self {
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Self {
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name,
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index: skeleton::Index::new(),
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handle_map: Map::new(),
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}
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}
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/// Retrieve the current count of *distinct* assertions placed in
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/// the dataspace.
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pub fn assertion_count(&self) -> usize {
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self.index.assertion_count()
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}
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/// Retrieve the current count of assertions, including
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/// duplicates, placed in the dataspace.
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pub fn endpoint_count(&self) -> isize {
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self.index.endpoint_count()
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}
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/// Retrieve the current count of
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/// [`Observe`][crate::schemas::dataspace::Observe] assertions in
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/// the dataspace.
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pub fn observer_count(&self) -> usize {
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self.index.observer_count()
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}
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}
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impl Entity<_Any> for Dataspace {
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fn assert(&mut self, t: &mut Activation, a: _Any, h: Handle) -> ActorResult {
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let is_new = self.index.insert(t, &a);
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tracing::trace!(dataspace = ?self.name, assertion = ?a, handle = ?h, ?is_new, "assert");
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if is_new {
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if let Ok(o) = language().parse::<Observe>(&a) {
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self.index.add_observer(t, &o.pattern, &o.observer);
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}
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}
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self.handle_map.insert(h, a);
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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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match self.handle_map.remove(&h) {
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None => tracing::warn!(dataspace = ?self.name, handle = ?h, "retract of unknown handle"),
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Some(a) => {
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let is_last = self.index.remove(t, &a);
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tracing::trace!(dataspace = ?self.name, assertion = ?a, handle = ?h, ?is_last, "retract");
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if is_last {
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if let Ok(o) = language().parse::<Observe>(&a) {
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self.index.remove_observer(t, o.pattern, &o.observer);
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}
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}
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}
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}
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Ok(())
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}
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fn message(&mut self, t: &mut Activation, m: _Any) -> ActorResult {
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tracing::trace!(dataspace = ?self.name, body = ?m, "message");
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self.index.send(t, &m);
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Ok(())
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}
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}
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