From 7b034675b70d5b8e9282b50db2979a9a90a4d1cf Mon Sep 17 00:00:00 2001
From: Sean McArthur <sean@seanmonstar.com>
Date: Fri, 4 Jul 2025 13:47:13 -0400
Subject: [PATCH] feat(rt): introduce quic traits

---
 Cargo.toml     |  3 +-
 src/rt/mod.rs  |  4 +++
 src/rt/quic.rs | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 src/rt/quic.rs

diff --git a/Cargo.toml b/Cargo.toml
index 3034cfeb57..a31b8813fd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -101,7 +101,8 @@ nightly = []
 level = "warn"
 check-cfg = [
     'cfg(hyper_unstable_tracing)',
-    'cfg(hyper_unstable_ffi)'
+    'cfg(hyper_unstable_ffi)',
+    'cfg(hyper_unstable_quic)',
 ]
 
 [package.metadata.docs.rs]
diff --git a/src/rt/mod.rs b/src/rt/mod.rs
index 0eb266974f..d1b2f81792 100644
--- a/src/rt/mod.rs
+++ b/src/rt/mod.rs
@@ -17,6 +17,10 @@ pub mod bounds;
 mod io;
 mod timer;
 
+#[cfg(hyper_unstable_quic)]
+#[cfg_attr(docsrs, doc(cfg(hyper_unstable_quic)))]
+pub mod quic;
+
 pub use self::io::{Read, ReadBuf, ReadBufCursor, Write};
 pub use self::timer::{Sleep, Timer};
 
diff --git a/src/rt/quic.rs b/src/rt/quic.rs
new file mode 100644
index 0000000000..18271d34a8
--- /dev/null
+++ b/src/rt/quic.rs
@@ -0,0 +1,91 @@
+//! Generic QUIC support
+
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+use bytes::Buf;
+
+// TODO: Should this be gated by an `http3` feature?
+
+/// A QUIC connection.
+pub trait Connection<B> {
+    /// Send streams that can be opened by this connection.
+    type SendStream: SendStream<B>;
+    /// Receive streams that can be accepted by this connection.
+    type RecvStream: RecvStream;
+    /// Bidirectional streams that can be opened or accepted by this connection.
+    type BidiStream: SendStream<B> + RecvStream;
+    /// Errors that may occur opening or accepting streams.
+    type Error;
+
+    // Accepting streams
+
+    // Q: shorten to bidi?
+    /// Accept a bidirection stream.
+    fn poll_accept_bidirectional_stream(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<Option<Self::BidiStream>, Self::Error>>;
+
+    /// Accept a unidirectional receive stream.
+    fn poll_accept_recv_stream(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<Option<Self::RecvStream>, Self::Error>>;
+
+    // Creating streams
+
+    // Q: shorten to bidi?
+    /// Open a bidirectional stream.
+    fn poll_open_bidirectional_stream(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<Self::BidiStream, Self::Error>>;
+
+    /// Open a unidirectional send stream.
+    fn poll_open_send_stream(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<Self::SendStream, Self::Error>>;
+}
+
+/// The send portion of a QUIC stream.
+pub trait SendStream<B> {
+    /// Errors that may happen trying to send data.
+    type Error; // bounds?
+    /// Polls that the stream is ready to send more data.
+    // Q: Should this be Pin<&mut Self>?
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>;
+    /// Send data on the stream.
+    fn send_data(&mut self, data: B) -> Result<(), Self::Error>;
+    // fn poll_flush?
+    /// finish?
+    fn poll_finish(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>;
+    /// Close the stream with an error code.
+    fn reset(&mut self, reset_code: u64);
+}
+
+/// The receive portion of a QUIC stream.
+pub trait RecvStream {
+    /// Buffers of data that can be received.
+    type Buf: Buf;
+    /// Errors that may be received.
+    type Error; // bounds?
+
+    // Q: should this be Pin?
+    /// Poll for more data received from the remote on this stream.
+    fn poll_data(&mut self, cx: &mut Context<'_>) -> Poll<Result<Option<Self::Buf>, Self::Error>>;
+    /// Signal to the remote peer to stop sending data.
+    fn stop_sending(&mut self, error_code: u64);
+}
+
+/// An optional trait if a QUIC stream can be split into two sides.
+pub trait BidiStream<B>: SendStream<B> + RecvStream {
+    /// The send side of a stream.
+    type SendStream: SendStream<B>;
+    /// The receive side of a stream.
+    type RecvStream: RecvStream;
+
+    /// Split this stream into two sides.
+    fn split(self) -> (Self::SendStream, Self::RecvStream);
+}