Zebra/zebra-consensus/src/redjubjub.rs

89 lines
2.8 KiB
Rust

//! Async RedJubjub batch verifier service
#[cfg(test)]
mod tests;
use std::{
future::Future,
mem,
pin::Pin,
task::{Context, Poll},
};
use rand::thread_rng;
use redjubjub::{batch, *};
use tokio::sync::broadcast::{channel, RecvError, Sender};
use tower::Service;
use tower_batch::BatchControl;
/// RedJubjub signature verifier service
pub struct Verifier {
batch: batch::Verifier,
// This uses a "broadcast" channel, which is an mpmc channel. Tokio also
// provides a spmc channel, "watch", but it only keeps the latest value, so
// using it would require thinking through whether it was possible for
// results from one batch to be mixed with another.
tx: Sender<Result<(), Error>>,
}
#[allow(clippy::new_without_default)]
impl Verifier {
/// Create a new RedJubjubVerifier instance
pub fn new() -> Self {
let batch = batch::Verifier::default();
// XXX(hdevalence) what's a reasonable choice here?
let (tx, _) = channel(10);
Self { tx, batch }
}
}
/// Type alias to clarify that this batch::Item is a RedJubjubItem
pub type Item = batch::Item;
impl Service<BatchControl<Item>> for Verifier {
type Response = ();
type Error = Error;
type Future = Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'static>>;
fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Poll::Ready(Ok(()))
}
fn call(&mut self, req: BatchControl<Item>) -> Self::Future {
match req {
BatchControl::Item(item) => {
tracing::trace!("got item");
self.batch.queue(item);
let mut rx = self.tx.subscribe();
Box::pin(async move {
match rx.recv().await {
Ok(result) => result,
Err(RecvError::Lagged(_)) => {
tracing::warn!(
"missed channel updates for the correct signature batch!"
);
Err(Error::InvalidSignature)
}
Err(RecvError::Closed) => panic!("verifier was dropped without flushing"),
}
})
}
BatchControl::Flush => {
tracing::trace!("got flush command");
let batch = mem::take(&mut self.batch);
let _ = self.tx.send(batch.verify(thread_rng()));
Box::pin(async { Ok(()) })
}
}
}
}
impl Drop for Verifier {
fn drop(&mut self) {
// We need to flush the current batch in case there are still any pending futures.
let batch = mem::take(&mut self.batch);
let _ = self.tx.send(batch.verify(thread_rng()));
}
}