h3: avoid needless copy when checking dgram queue
In an old version of the DATAGRAM poll event, it returned an HTTP/3 datagram
flow ID, which required peeking at the first 8 bytes of the QUIC frame
payload at the front of the queue.
When we changed to edge-triggered events, we changed the logic to
always return the placeholder value 0. However, we didn't change
the logic to avoid peeking at the data, which meant we left a
needless 8-byte allocation and copy.
This change removes the needless copy, replacing it instead with a check
of the queue length to determine if the edge-trigger should fire
or not.
diff --git a/quiche/src/h3/mod.rs b/quiche/src/h3/mod.rs
index 0af162f..1cec93e 100644
--- a/quiche/src/h3/mod.rs
+++ b/quiche/src/h3/mod.rs
@@ -1337,29 +1337,19 @@
fn process_dgrams(
&mut self, conn: &mut super::Connection,
) -> Result<(u64, Event)> {
- let mut d = [0; 8];
+ if conn.dgram_recv_queue_len() > 0 {
+ if self.dgram_event_triggered {
+ return Err(Error::Done);
+ }
- match conn.dgram_recv_peek(&mut d, 8) {
- Ok(_) => {
- if self.dgram_event_triggered {
- return Err(Error::Done);
- }
+ self.dgram_event_triggered = true;
- self.dgram_event_triggered = true;
-
- Ok((0, Event::Datagram))
- },
-
- Err(crate::Error::Done) => {
- // The dgram recv queue is empty, so re-arm the Datagram event
- // so it is issued next time a DATAGRAM is received.
- self.dgram_event_triggered = false;
-
- Err(Error::Done)
- },
-
- Err(e) => Err(Error::TransportError(e)),
+ return Ok((0, Event::Datagram));
}
+
+ self.dgram_event_triggered = false;
+
+ Err(Error::Done)
}
/// Reads request or response body data into the provided buffer.
