A few minor changes to the API. (#52)

The only salvagable remains from a multi-day refactoring effort. The
main benefit is that Setup messages are no longer part of the Message
enum, so match will be a lot easier.

moq-transport/src/lib.rs

@@ -6,4 +6,5 @@ pub mod setup;
 
 pub use coding::VarInt;
 pub use message::Message;
+pub use object::Object;
 pub use session::Session;

moq-transport/src/message/mod.rs

@@ -19,7 +19,6 @@ pub use subscribe_error::*;
 pub use subscribe_ok::*;
 
 use crate::coding::{DecodeError, EncodeError, VarInt};
-use crate::setup;
 
 use std::fmt;
 
@@ -81,16 +80,12 @@ macro_rules! message_types {
     }
 }
 
-// Just so we can use the macro above.
-type SetupClient = setup::Client;
-type SetupServer = setup::Server;
-
 // Each message is prefixed with the given VarInt type.
 message_types! {
 	// NOTE: Object and Setup are in other modules.
 	// Object = 0x0
-	SetupClient = 0x1,
-	SetupServer = 0x2,
+	// SetupClient = 0x1
+	// SetupServer = 0x2
 	Subscribe = 0x3,
 	SubscribeOk = 0x4,
 	SubscribeError = 0x5,

moq-transport/src/object/header.rs

@@ -1,54 +0,0 @@
-use crate::coding::{DecodeError, EncodeError, VarInt};
-
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
-use webtransport_generic::{RecvStream, SendStream};
-
-#[derive(Debug)]
-pub struct Header {
-	// An ID for this track.
-	// Proposal: https://github.com/moq-wg/moq-transport/issues/209
-	pub track: VarInt,
-
-	// The group sequence number.
-	pub group: VarInt,
-
-	// The object sequence number.
-	pub sequence: VarInt,
-
-	// The priority/send order.
-	// Proposal: int32 instead of a varint.
-	pub send_order: i32,
-}
-
-impl Header {
-	pub async fn decode<R: RecvStream>(r: &mut R) -> Result<Self, DecodeError> {
-		let typ = VarInt::decode(r).await?;
-		if typ.into_inner() != 0 {
-			return Err(DecodeError::InvalidType(typ));
-		}
-
-		// NOTE: size has been omitted
-
-		let track = VarInt::decode(r).await?;
-		let group = VarInt::decode(r).await?;
-		let sequence = VarInt::decode(r).await?;
-		let send_order = r.read_i32().await?; // big-endian
-
-		Ok(Self {
-			track,
-			group,
-			sequence,
-			send_order,
-		})
-	}
-
-	pub async fn encode<W: SendStream>(&self, w: &mut W) -> Result<(), EncodeError> {
-		VarInt::from_u32(0).encode(w).await?;
-		self.track.encode(w).await?;
-		self.group.encode(w).await?;
-		self.sequence.encode(w).await?;
-		w.write_i32(self.send_order).await?;
-
-		Ok(())
-	}
-}

moq-transport/src/object/mod.rs

@@ -1,7 +1,60 @@
-mod header;
 mod receiver;
 mod sender;
 
-pub use header::*;
 pub use receiver::*;
 pub use sender::*;
+
+use crate::coding::{DecodeError, EncodeError, VarInt};
+
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use webtransport_generic::{RecvStream, SendStream};
+
+#[derive(Debug)]
+pub struct Object {
+	// An ID for this track.
+	// Proposal: https://github.com/moq-wg/moq-transport/issues/209
+	pub track: VarInt,
+
+	// The group sequence number.
+	pub group: VarInt,
+
+	// The object sequence number.
+	pub sequence: VarInt,
+
+	// The priority/send order.
+	// Proposal: int32 instead of a varint.
+	pub send_order: i32,
+}
+
+impl Object {
+	pub async fn decode<R: RecvStream>(r: &mut R) -> Result<Self, DecodeError> {
+		let typ = VarInt::decode(r).await?;
+		if typ.into_inner() != 0 {
+			return Err(DecodeError::InvalidType(typ));
+		}
+
+		// NOTE: size has been omitted
+
+		let track = VarInt::decode(r).await?;
+		let group = VarInt::decode(r).await?;
+		let sequence = VarInt::decode(r).await?;
+		let send_order = r.read_i32().await?; // big-endian
+
+		Ok(Self {
+			track,
+			group,
+			sequence,
+			send_order,
+		})
+	}
+
+	pub async fn encode<W: SendStream>(&self, w: &mut W) -> Result<(), EncodeError> {
+		VarInt::from_u32(0).encode(w).await?;
+		self.track.encode(w).await?;
+		self.group.encode(w).await?;
+		self.sequence.encode(w).await?;
+		w.write_i32(self.send_order).await?;
+
+		Ok(())
+	}
+}

moq-transport/src/object/receiver.rs

@@ -1,4 +1,4 @@
-use crate::object::Header;
+use crate::Object;
 
 use anyhow::Context;
 
@@ -10,7 +10,7 @@ pub struct Receiver<S: Session> {
 	session: S,
 
 	// Streams that we've accepted but haven't read the header from yet.
-	streams: JoinSet<anyhow::Result<(Header, S::RecvStream)>>,
+	streams: JoinSet<anyhow::Result<(Object, S::RecvStream)>>,
 }
 
 impl<S: Session> Receiver<S> {
@@ -21,7 +21,7 @@ impl<S: Session> Receiver<S> {
 		}
 	}
 
-	pub async fn recv(&mut self) -> anyhow::Result<(Header, S::RecvStream)> {
+	pub async fn recv(&mut self) -> anyhow::Result<(Object, S::RecvStream)> {
 		loop {
 			tokio::select! {
 				res = self.session.accept_uni() => {
@@ -35,8 +35,8 @@ impl<S: Session> Receiver<S> {
 		}
 	}
 
-	async fn read(mut stream: S::RecvStream) -> anyhow::Result<(Header, S::RecvStream)> {
-		let header = Header::decode(&mut stream).await?;
+	async fn read(mut stream: S::RecvStream) -> anyhow::Result<(Object, S::RecvStream)> {
+		let header = Object::decode(&mut stream).await?;
 		Ok((header, stream))
 	}
 }

moq-transport/src/object/sender.rs

@@ -1,6 +1,6 @@
 use anyhow::Context;
 
-use crate::object::Header;
+use crate::Object;
 
 use webtransport_generic::{SendStream, Session};
 
@@ -16,11 +16,11 @@ impl<S: Session> Sender<S> {
 		Self { session }
 	}
 
-	pub async fn open(&mut self, header: Header) -> anyhow::Result<S::SendStream> {
+	pub async fn open(&mut self, object: Object) -> anyhow::Result<S::SendStream> {
 		let mut stream = self.session.open_uni().await.context("failed to open uni stream")?;
 
-		stream.set_priority(header.send_order);
-		header.encode(&mut stream).await.context("failed to write header")?;
+		stream.set_priority(object.send_order);
+		object.encode(&mut stream).await.context("failed to write header")?;
 
 		// log::info!("created stream: {:?}", header);
 

moq-transport/src/session.rs

@@ -14,15 +14,11 @@ impl<S: WTSession> Session<S> {
 	/// Called by a server with an established WebTransport session.
 	// TODO close the session with an error code
 	pub async fn accept(session: S, role: setup::Role) -> anyhow::Result<Self> {
-		let (send, recv) = session.accept_bi().await.context("failed to accept bidi stream")?;
+		let (mut send, mut recv) = session.accept_bi().await.context("failed to accept bidi stream")?;
 
-		let mut send_control = message::Sender::new(send);
-		let mut recv_control = message::Receiver::new(recv);
-
-		let setup_client = match recv_control.recv().await.context("failed to read SETUP")? {
-			message::Message::SetupClient(setup) => setup,
-			_ => anyhow::bail!("expected CLIENT SETUP"),
-		};
+		let setup_client = setup::Client::decode(&mut recv)
+			.await
+			.context("failed to read CLIENT SETUP")?;
 
 		setup_client
 			.versions
@@ -39,11 +35,14 @@ impl<S: WTSession> Session<S> {
 			version: setup::Version::DRAFT_00,
 		};
 
-		send_control
-			.send(message::Message::SetupServer(setup_server))
+		setup_server
+			.encode(&mut send)
 			.await
 			.context("failed to send setup server")?;
 
+		let send_control = message::Sender::new(send);
+		let recv_control = message::Receiver::new(recv);
+
 		let send_objects = object::Sender::new(session.clone());
 		let recv_objects = object::Receiver::new(session.clone());
 
@@ -57,10 +56,7 @@ impl<S: WTSession> Session<S> {
 
 	/// Called by a client with an established WebTransport session.
 	pub async fn connect(session: S, role: setup::Role) -> anyhow::Result<Self> {
-		let (send, recv) = session.open_bi().await.context("failed to oen bidi stream")?;
-
-		let mut send_control = message::Sender::new(send);
-		let mut recv_control = message::Receiver::new(recv);
+		let (mut send, mut recv) = session.open_bi().await.context("failed to oen bidi stream")?;
 
 		let setup_client = setup::Client {
 			role,
@@ -68,15 +64,12 @@ impl<S: WTSession> Session<S> {
 			path: "".to_string(),
 		};
 
-		send_control
-			.send(message::Message::SetupClient(setup_client))
+		setup_client
+			.encode(&mut send)
 			.await
 			.context("failed to send SETUP CLIENT")?;
 
-		let setup_server = match recv_control.recv().await.context("failed to read SETUP")? {
-			message::Message::SetupServer(setup) => setup,
-			_ => anyhow::bail!("expected SERVER SETUP"),
-		};
+		let setup_server = setup::Server::decode(&mut recv).await.context("failed to read SETUP")?;
 
 		if setup_server.version != setup::Version::DRAFT_00 {
 			anyhow::bail!("unsupported version: {:?}", setup_server.version);
@@ -86,6 +79,9 @@ impl<S: WTSession> Session<S> {
 			anyhow::bail!("incompatible roles: {:?} {:?}", role, setup_server.role);
 		}
 
+		let send_control = message::Sender::new(send);
+		let recv_control = message::Receiver::new(recv);
+
 		let send_objects = object::Sender::new(session.clone());
 		let recv_objects = object::Receiver::new(session.clone());
 

moq-transport/src/setup/client.rs

@@ -1,5 +1,8 @@
 use super::{Role, Versions};
-use crate::coding::{decode_string, encode_string, DecodeError, EncodeError};
+use crate::{
+	coding::{decode_string, encode_string, DecodeError, EncodeError},
+	VarInt,
+};
 
 use webtransport_generic::{RecvStream, SendStream};
 
@@ -22,6 +25,11 @@ pub struct Client {
 
 impl Client {
 	pub async fn decode<R: RecvStream>(r: &mut R) -> Result<Self, DecodeError> {
+		let typ = VarInt::decode(r).await?;
+		if typ.into_inner() != 1 {
+			return Err(DecodeError::InvalidType(typ));
+		}
+
 		let versions = Versions::decode(r).await?;
 		let role = Role::decode(r).await?;
 		let path = decode_string(r).await?;
@@ -30,6 +38,7 @@ impl Client {
 	}
 
 	pub async fn encode<W: SendStream>(&self, w: &mut W) -> Result<(), EncodeError> {
+		VarInt::from_u32(1).encode(w).await?;
 		self.versions.encode(w).await?;
 		self.role.encode(w).await?;
 		encode_string(&self.path, w).await?;

moq-transport/src/setup/server.rs

@@ -1,5 +1,8 @@
 use super::{Role, Version};
-use crate::coding::{DecodeError, EncodeError};
+use crate::{
+	coding::{DecodeError, EncodeError},
+	VarInt,
+};
 
 use webtransport_generic::{RecvStream, SendStream};
 
@@ -18,6 +21,11 @@ pub struct Server {
 
 impl Server {
 	pub async fn decode<R: RecvStream>(r: &mut R) -> Result<Self, DecodeError> {
+		let typ = VarInt::decode(r).await?;
+		if typ.into_inner() != 2 {
+			return Err(DecodeError::InvalidType(typ));
+		}
+
 		let version = Version::decode(r).await?;
 		let role = Role::decode(r).await?;
 
@@ -25,6 +33,7 @@ impl Server {
 	}
 
 	pub async fn encode<W: SendStream>(&self, w: &mut W) -> Result<(), EncodeError> {
+		VarInt::from_u32(2).encode(w).await?;
 		self.version.encode(w).await?;
 		self.role.encode(w).await?;
 

moq-warp/src/relay/contribute.rs

@@ -7,7 +7,7 @@ use tokio::sync::mpsc;
 use tokio::task::JoinSet; // lock across await boundaries
 
 use moq_transport::message::{Announce, AnnounceError, AnnounceOk, Subscribe, SubscribeError, SubscribeOk};
-use moq_transport::{object, VarInt};
+use moq_transport::{object, Object, VarInt};
 use webtransport_generic::Session as WTSession;
 
 use bytes::BytesMut;
@@ -89,15 +89,15 @@ impl<S: WTSession> Session<S> {
 		}
 	}
 
-	async fn receive_object(&mut self, header: object::Header, stream: S::RecvStream) -> anyhow::Result<()> {
-		let track = header.track;
+	async fn receive_object(&mut self, obj: Object, stream: S::RecvStream) -> anyhow::Result<()> {
+		let track = obj.track;
 
 		// Keep objects in memory for 10s
 		let expires = time::Instant::now() + time::Duration::from_secs(10);
 
 		let segment = segment::Info {
-			sequence: header.sequence,
-			send_order: header.send_order,
+			sequence: obj.sequence,
+			send_order: obj.send_order,
 			expires: Some(expires),
 		};
 

moq-warp/src/relay/distribute.rs

@@ -4,7 +4,7 @@ use tokio::io::AsyncWriteExt;
 use tokio::task::JoinSet; // allows locking across await
 
 use moq_transport::message::{Announce, AnnounceError, AnnounceOk, Subscribe, SubscribeError, SubscribeOk};
-use moq_transport::{object, VarInt};
+use moq_transport::{object, Object, VarInt};
 use webtransport_generic::Session as WTSession;
 
 use crate::model::{segment, track};
@@ -163,7 +163,7 @@ impl<S: WTSession> Session<S> {
 		track_id: VarInt,
 		mut segment: segment::Subscriber,
 	) -> anyhow::Result<()> {
-		let object = object::Header {
+		let object = Object {
 			track: track_id,
 			group: segment.sequence,
 			sequence: VarInt::from_u32(0), // Always zero since we send an entire group as an object