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//! Code to remotely notify other crates about changes in the status of the
//! `GuardMgr`.
use std::{pin::Pin, task::Poll};
use crate::skew::SkewEstimate;
use educe::Educe;
use futures::{Stream, StreamExt};
use tor_basic_utils::skip_fmt;
/// A stream of [`SkewEstimate`] events.
///
/// Note that this stream can be lossy: if multiple events trigger before you
/// read from it, you will only get the most recent estimate.
//
// SEMVER NOTE: this type is re-exported from tor-circmgr.
#[derive(Clone, Educe)]
#[educe(Debug)]
pub struct ClockSkewEvents {
/// The `postage::watch::Receiver` that we're wrapping.
///
/// We wrap this type so that we don't expose its entire API, and so that we
/// can migrate to some other implementation in the future if we want.
#[educe(Debug(method = "skip_fmt"))]
pub(crate) inner: postage::watch::Receiver<Option<SkewEstimate>>,
}
impl Stream for ClockSkewEvents {
type Item = Option<SkewEstimate>;
fn poll_next(
mut self: Pin<&mut Self>,
cx: &mut std::task::Context<'_>,
) -> Poll<Option<Self::Item>> {
self.inner.poll_next_unpin(cx)
}
}
impl ClockSkewEvents {
/// Return our best estimate of our current clock skew, based on reports from the
/// guards and fallbacks we have contacted.
pub fn get(&self) -> Option<SkewEstimate> {
self.inner.borrow().clone()
}
}