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https://github.com/neondatabase/neon.git
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a22be5af72
Migrates the remaining crates to edition 2024. We like to stay on the latest edition if possible. There is no functional changes, however some code changes had to be done to accommodate the edition's breaking changes. Like the previous migration PRs, this is comprised of three commits: * the first does the edition update and makes `cargo check`/`cargo clippy` pass. we had to update bindgen to make its output [satisfy the requirements of edition 2024](https://doc.rust-lang.org/edition-guide/rust-2024/unsafe-extern.html) * the second commit does a `cargo fmt` for the new style edition. * the third commit reorders imports as a one-off change. As before, it is entirely optional. Part of #10918
84 lines
2.0 KiB
Rust
84 lines
2.0 KiB
Rust
//! A helper to rate limit operations.
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use std::time::{Duration, Instant};
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pub struct RateLimit {
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last: Option<Instant>,
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interval: Duration,
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dropped: u64,
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}
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pub struct RateLimitStats(u64);
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impl std::fmt::Display for RateLimitStats {
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fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
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write!(f, "{} dropped calls", self.0)
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}
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}
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impl RateLimit {
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pub fn new(interval: Duration) -> Self {
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Self {
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last: None,
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interval,
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dropped: 0,
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}
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}
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/// Call `f` if the rate limit allows.
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/// Don't call it otherwise.
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pub fn call<F: FnOnce()>(&mut self, f: F) {
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self.call2(|_| f())
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}
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pub fn call2<F: FnOnce(RateLimitStats)>(&mut self, f: F) {
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let now = Instant::now();
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match self.last {
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Some(last) if now - last <= self.interval => {
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// ratelimit
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self.dropped += 1;
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}
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_ => {
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self.last = Some(now);
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f(RateLimitStats(self.dropped));
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self.dropped = 0;
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}
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use std::sync::atomic::AtomicUsize;
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#[test]
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fn basics() {
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use std::sync::atomic::Ordering::Relaxed;
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use std::time::Duration;
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use super::RateLimit;
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let called = AtomicUsize::new(0);
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let mut f = RateLimit::new(Duration::from_millis(100));
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let cl = || {
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called.fetch_add(1, Relaxed);
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};
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f.call(cl);
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assert_eq!(called.load(Relaxed), 1);
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f.call(cl);
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assert_eq!(called.load(Relaxed), 1);
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f.call(cl);
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assert_eq!(called.load(Relaxed), 1);
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std::thread::sleep(Duration::from_millis(100));
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f.call(cl);
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assert_eq!(called.load(Relaxed), 2);
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f.call(cl);
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assert_eq!(called.load(Relaxed), 2);
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std::thread::sleep(Duration::from_millis(100));
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f.call(cl);
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assert_eq!(called.load(Relaxed), 3);
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}
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}
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