web3-proxy/rate-counter/src/lib.rs
2023-04-10 15:06:40 -07:00

36 lines
849 B
Rust

//! A counter of events in a time period.
use std::collections::VecDeque;
use tokio::time::{Duration, Instant};
/// Measures ticks in a time period.
#[derive(Debug)]
pub struct RateCounter {
period: Duration,
items: VecDeque<Instant>,
}
impl RateCounter {
pub fn new(period: Duration) -> Self {
let items = VecDeque::new();
Self { period, items }
}
/// update the counter and return the rate for the current period
/// true if the current time should be counted
pub fn update(&mut self, tick: bool) -> usize {
let now = Instant::now();
let too_old = now - self.period;
while self.items.front().map_or(false, |t| *t < too_old) {
self.items.pop_front();
}
if tick {
self.items.push_back(now);
}
self.items.len()
}
}