tor_guardmgr/
events.rs

1//! Code to remotely notify other crates about changes in the status of the
2//! `GuardMgr`.
3
4use std::{pin::Pin, task::Poll};
5
6use crate::skew::SkewEstimate;
7use educe::Educe;
8use futures::{Stream, StreamExt};
9use tor_basic_utils::skip_fmt;
10
11/// A stream of [`SkewEstimate`] events.
12///
13/// Note that this stream can be lossy: if multiple events trigger before you
14/// read from it, you will only get the most recent estimate.
15//
16// SEMVER NOTE: this type is re-exported from tor-circmgr.
17#[derive(Clone, Educe)]
18#[educe(Debug)]
19pub struct ClockSkewEvents {
20    /// The `postage::watch::Receiver` that we're wrapping.
21    ///
22    /// We wrap this type so that we don't expose its entire API, and so that we
23    /// can migrate to some other implementation in the future if we want.
24    #[educe(Debug(method = "skip_fmt"))]
25    pub(crate) inner: postage::watch::Receiver<Option<SkewEstimate>>,
26}
27
28impl Stream for ClockSkewEvents {
29    type Item = Option<SkewEstimate>;
30
31    fn poll_next(
32        mut self: Pin<&mut Self>,
33        cx: &mut std::task::Context<'_>,
34    ) -> Poll<Option<Self::Item>> {
35        self.inner.poll_next_unpin(cx)
36    }
37}
38impl ClockSkewEvents {
39    /// Return our best estimate of our current clock skew, based on reports from the
40    /// guards and fallbacks we have contacted.
41    pub fn get(&self) -> Option<SkewEstimate> {
42        self.inner.borrow().clone()
43    }
44}