polkadot_node_metrics/
metronome.rs

1// Copyright (C) Parity Technologies (UK) Ltd.
2// This file is part of Polkadot.
3
4// Polkadot is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8
9// Polkadot is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13
14// You should have received a copy of the GNU General Public License
15// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
16
17use futures::prelude::*;
18use futures_timer::Delay;
19use std::{
20	pin::Pin,
21	task::{Context, Poll},
22	time::Duration,
23};
24
25#[derive(Copy, Clone)]
26enum MetronomeState {
27	Snooze,
28	SetAlarm,
29}
30
31/// Create a stream of ticks with a defined cycle duration.
32pub struct Metronome {
33	delay: Delay,
34	period: Duration,
35	state: MetronomeState,
36}
37
38impl Metronome {
39	/// Create a new metronome source with a defined cycle duration.
40	pub fn new(cycle: Duration) -> Self {
41		let period = cycle.into();
42		Self { period, delay: Delay::new(period), state: MetronomeState::Snooze }
43	}
44}
45
46impl futures::Stream for Metronome {
47	type Item = ();
48	fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
49		loop {
50			match self.state {
51				MetronomeState::SetAlarm => {
52					let val = self.period;
53					self.delay.reset(val);
54					self.state = MetronomeState::Snooze;
55				},
56				MetronomeState::Snooze => {
57					if !Pin::new(&mut self.delay).poll(cx).is_ready() {
58						break
59					}
60					self.state = MetronomeState::SetAlarm;
61					return Poll::Ready(Some(()))
62				},
63			}
64		}
65		Poll::Pending
66	}
67}
polkadot_node_metrics/metronome.rs

polkadot_node_metrics/
metronome.rs
