1use crate::proto::{self, AnyTypedEnvelope, EnvelopedMessage, MessageStream, RequestMessage};
2use anyhow::{anyhow, Context, Result};
3use async_lock::{Mutex, RwLock};
4use async_tungstenite::tungstenite::{Error as WebSocketError, Message as WebSocketMessage};
5use futures::{FutureExt, StreamExt};
6use postage::{
7 mpsc,
8 prelude::{Sink as _, Stream as _},
9};
10use std::{
11 collections::HashMap,
12 fmt,
13 future::Future,
14 marker::PhantomData,
15 sync::{
16 atomic::{self, AtomicU32},
17 Arc,
18 },
19};
20
21#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
22pub struct ConnectionId(pub u32);
23
24impl fmt::Display for ConnectionId {
25 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
26 self.0.fmt(f)
27 }
28}
29
30#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
31pub struct PeerId(pub u32);
32
33impl fmt::Display for PeerId {
34 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
35 self.0.fmt(f)
36 }
37}
38
39pub struct Receipt<T> {
40 pub sender_id: ConnectionId,
41 pub message_id: u32,
42 payload_type: PhantomData<T>,
43}
44
45impl<T> Clone for Receipt<T> {
46 fn clone(&self) -> Self {
47 Self {
48 sender_id: self.sender_id,
49 message_id: self.message_id,
50 payload_type: PhantomData,
51 }
52 }
53}
54
55impl<T> Copy for Receipt<T> {}
56
57pub struct TypedEnvelope<T> {
58 pub sender_id: ConnectionId,
59 pub original_sender_id: Option<PeerId>,
60 pub message_id: u32,
61 pub payload: T,
62}
63
64impl<T> TypedEnvelope<T> {
65 pub fn original_sender_id(&self) -> Result<PeerId> {
66 self.original_sender_id
67 .ok_or_else(|| anyhow!("missing original_sender_id"))
68 }
69}
70
71impl<T: RequestMessage> TypedEnvelope<T> {
72 pub fn receipt(&self) -> Receipt<T> {
73 Receipt {
74 sender_id: self.sender_id,
75 message_id: self.message_id,
76 payload_type: PhantomData,
77 }
78 }
79}
80
81pub struct Peer {
82 connections: RwLock<HashMap<ConnectionId, Connection>>,
83 next_connection_id: AtomicU32,
84}
85
86#[derive(Clone)]
87struct Connection {
88 outgoing_tx: mpsc::Sender<proto::Envelope>,
89 next_message_id: Arc<AtomicU32>,
90 response_channels: Arc<Mutex<HashMap<u32, mpsc::Sender<proto::Envelope>>>>,
91}
92
93impl Peer {
94 pub fn new() -> Arc<Self> {
95 Arc::new(Self {
96 connections: Default::default(),
97 next_connection_id: Default::default(),
98 })
99 }
100
101 pub async fn add_connection<Conn>(
102 self: &Arc<Self>,
103 conn: Conn,
104 ) -> (
105 ConnectionId,
106 impl Future<Output = anyhow::Result<()>> + Send,
107 mpsc::Receiver<Box<dyn AnyTypedEnvelope>>,
108 )
109 where
110 Conn: futures::Sink<WebSocketMessage, Error = WebSocketError>
111 + futures::Stream<Item = Result<WebSocketMessage, WebSocketError>>
112 + Send
113 + Unpin,
114 {
115 let (tx, rx) = conn.split();
116 let connection_id = ConnectionId(
117 self.next_connection_id
118 .fetch_add(1, atomic::Ordering::SeqCst),
119 );
120 let (mut incoming_tx, incoming_rx) = mpsc::channel(64);
121 let (outgoing_tx, mut outgoing_rx) = mpsc::channel(64);
122 let connection = Connection {
123 outgoing_tx,
124 next_message_id: Default::default(),
125 response_channels: Default::default(),
126 };
127 let mut writer = MessageStream::new(tx);
128 let mut reader = MessageStream::new(rx);
129
130 let response_channels = connection.response_channels.clone();
131 let handle_io = async move {
132 loop {
133 let read_message = reader.read_message().fuse();
134 futures::pin_mut!(read_message);
135 loop {
136 futures::select_biased! {
137 incoming = read_message => match incoming {
138 Ok(incoming) => {
139 if let Some(responding_to) = incoming.responding_to {
140 let channel = response_channels.lock().await.remove(&responding_to);
141 if let Some(mut tx) = channel {
142 tx.send(incoming).await.ok();
143 } else {
144 log::warn!("received RPC response to unknown request {}", responding_to);
145 }
146 } else {
147 if let Some(envelope) = proto::build_typed_envelope(connection_id, incoming) {
148 if incoming_tx.send(envelope).await.is_err() {
149 response_channels.lock().await.clear();
150 return Ok(())
151 }
152 } else {
153 log::error!("unable to construct a typed envelope");
154 }
155 }
156
157 break;
158 }
159 Err(error) => {
160 response_channels.lock().await.clear();
161 Err(error).context("received invalid RPC message")?;
162 }
163 },
164 outgoing = outgoing_rx.recv().fuse() => match outgoing {
165 Some(outgoing) => {
166 if let Err(result) = writer.write_message(&outgoing).await {
167 response_channels.lock().await.clear();
168 Err(result).context("failed to write RPC message")?;
169 }
170 }
171 None => {
172 response_channels.lock().await.clear();
173 return Ok(())
174 }
175 }
176 }
177 }
178 }
179 };
180
181 self.connections
182 .write()
183 .await
184 .insert(connection_id, connection);
185
186 (connection_id, handle_io, incoming_rx)
187 }
188
189 pub async fn disconnect(&self, connection_id: ConnectionId) {
190 self.connections.write().await.remove(&connection_id);
191 }
192
193 pub async fn reset(&self) {
194 self.connections.write().await.clear();
195 }
196
197 pub fn request<T: RequestMessage>(
198 self: &Arc<Self>,
199 receiver_id: ConnectionId,
200 request: T,
201 ) -> impl Future<Output = Result<T::Response>> {
202 self.request_internal(None, receiver_id, request)
203 }
204
205 pub fn forward_request<T: RequestMessage>(
206 self: &Arc<Self>,
207 sender_id: ConnectionId,
208 receiver_id: ConnectionId,
209 request: T,
210 ) -> impl Future<Output = Result<T::Response>> {
211 self.request_internal(Some(sender_id), receiver_id, request)
212 }
213
214 pub fn request_internal<T: RequestMessage>(
215 self: &Arc<Self>,
216 original_sender_id: Option<ConnectionId>,
217 receiver_id: ConnectionId,
218 request: T,
219 ) -> impl Future<Output = Result<T::Response>> {
220 let this = self.clone();
221 let (tx, mut rx) = mpsc::channel(1);
222 async move {
223 let mut connection = this.connection(receiver_id).await?;
224 let message_id = connection
225 .next_message_id
226 .fetch_add(1, atomic::Ordering::SeqCst);
227 connection
228 .response_channels
229 .lock()
230 .await
231 .insert(message_id, tx);
232 connection
233 .outgoing_tx
234 .send(request.into_envelope(message_id, None, original_sender_id.map(|id| id.0)))
235 .await
236 .map_err(|_| anyhow!("connection was closed"))?;
237 let response = rx
238 .recv()
239 .await
240 .ok_or_else(|| anyhow!("connection was closed"))?;
241 if let Some(proto::envelope::Payload::Error(error)) = &response.payload {
242 Err(anyhow!("request failed").context(error.message.clone()))
243 } else {
244 T::Response::from_envelope(response)
245 .ok_or_else(|| anyhow!("received response of the wrong type"))
246 }
247 }
248 }
249
250 pub fn send<T: EnvelopedMessage>(
251 self: &Arc<Self>,
252 receiver_id: ConnectionId,
253 message: T,
254 ) -> impl Future<Output = Result<()>> {
255 let this = self.clone();
256 async move {
257 let mut connection = this.connection(receiver_id).await?;
258 let message_id = connection
259 .next_message_id
260 .fetch_add(1, atomic::Ordering::SeqCst);
261 connection
262 .outgoing_tx
263 .send(message.into_envelope(message_id, None, None))
264 .await?;
265 Ok(())
266 }
267 }
268
269 pub fn forward_send<T: EnvelopedMessage>(
270 self: &Arc<Self>,
271 sender_id: ConnectionId,
272 receiver_id: ConnectionId,
273 message: T,
274 ) -> impl Future<Output = Result<()>> {
275 let this = self.clone();
276 async move {
277 let mut connection = this.connection(receiver_id).await?;
278 let message_id = connection
279 .next_message_id
280 .fetch_add(1, atomic::Ordering::SeqCst);
281 connection
282 .outgoing_tx
283 .send(message.into_envelope(message_id, None, Some(sender_id.0)))
284 .await?;
285 Ok(())
286 }
287 }
288
289 pub fn respond<T: RequestMessage>(
290 self: &Arc<Self>,
291 receipt: Receipt<T>,
292 response: T::Response,
293 ) -> impl Future<Output = Result<()>> {
294 let this = self.clone();
295 async move {
296 let mut connection = this.connection(receipt.sender_id).await?;
297 let message_id = connection
298 .next_message_id
299 .fetch_add(1, atomic::Ordering::SeqCst);
300 connection
301 .outgoing_tx
302 .send(response.into_envelope(message_id, Some(receipt.message_id), None))
303 .await?;
304 Ok(())
305 }
306 }
307
308 pub fn respond_with_error<T: RequestMessage>(
309 self: &Arc<Self>,
310 receipt: Receipt<T>,
311 response: proto::Error,
312 ) -> impl Future<Output = Result<()>> {
313 let this = self.clone();
314 async move {
315 let mut connection = this.connection(receipt.sender_id).await?;
316 let message_id = connection
317 .next_message_id
318 .fetch_add(1, atomic::Ordering::SeqCst);
319 connection
320 .outgoing_tx
321 .send(response.into_envelope(message_id, Some(receipt.message_id), None))
322 .await?;
323 Ok(())
324 }
325 }
326
327 fn connection(
328 self: &Arc<Self>,
329 connection_id: ConnectionId,
330 ) -> impl Future<Output = Result<Connection>> {
331 let this = self.clone();
332 async move {
333 let connections = this.connections.read().await;
334 let connection = connections
335 .get(&connection_id)
336 .ok_or_else(|| anyhow!("no such connection: {}", connection_id))?;
337 Ok(connection.clone())
338 }
339 }
340}
341
342#[cfg(test)]
343mod tests {
344 use super::*;
345 use crate::{test, TypedEnvelope};
346
347 #[test]
348 fn test_request_response() {
349 smol::block_on(async move {
350 // create 2 clients connected to 1 server
351 let server = Peer::new();
352 let client1 = Peer::new();
353 let client2 = Peer::new();
354
355 let (client1_to_server_conn, server_to_client_1_conn) = test::Channel::bidirectional();
356 let (client1_conn_id, io_task1, _) =
357 client1.add_connection(client1_to_server_conn).await;
358 let (_, io_task2, incoming1) = server.add_connection(server_to_client_1_conn).await;
359
360 let (client2_to_server_conn, server_to_client_2_conn) = test::Channel::bidirectional();
361 let (client2_conn_id, io_task3, _) =
362 client2.add_connection(client2_to_server_conn).await;
363 let (_, io_task4, incoming2) = server.add_connection(server_to_client_2_conn).await;
364
365 smol::spawn(io_task1).detach();
366 smol::spawn(io_task2).detach();
367 smol::spawn(io_task3).detach();
368 smol::spawn(io_task4).detach();
369 smol::spawn(handle_messages(incoming1, server.clone())).detach();
370 smol::spawn(handle_messages(incoming2, server.clone())).detach();
371
372 assert_eq!(
373 client1
374 .request(client1_conn_id, proto::Ping { id: 1 },)
375 .await
376 .unwrap(),
377 proto::Pong { id: 1 }
378 );
379
380 assert_eq!(
381 client2
382 .request(client2_conn_id, proto::Ping { id: 2 },)
383 .await
384 .unwrap(),
385 proto::Pong { id: 2 }
386 );
387
388 assert_eq!(
389 client1
390 .request(
391 client1_conn_id,
392 proto::OpenBuffer {
393 worktree_id: 1,
394 path: "path/one".to_string(),
395 },
396 )
397 .await
398 .unwrap(),
399 proto::OpenBufferResponse {
400 buffer: Some(proto::Buffer {
401 id: 101,
402 content: "path/one content".to_string(),
403 history: vec![],
404 selections: vec![],
405 }),
406 }
407 );
408
409 assert_eq!(
410 client2
411 .request(
412 client2_conn_id,
413 proto::OpenBuffer {
414 worktree_id: 2,
415 path: "path/two".to_string(),
416 },
417 )
418 .await
419 .unwrap(),
420 proto::OpenBufferResponse {
421 buffer: Some(proto::Buffer {
422 id: 102,
423 content: "path/two content".to_string(),
424 history: vec![],
425 selections: vec![],
426 }),
427 }
428 );
429
430 client1.disconnect(client1_conn_id).await;
431 client2.disconnect(client1_conn_id).await;
432
433 async fn handle_messages(
434 mut messages: mpsc::Receiver<Box<dyn AnyTypedEnvelope>>,
435 peer: Arc<Peer>,
436 ) -> Result<()> {
437 while let Some(envelope) = messages.next().await {
438 let envelope = envelope.into_any();
439 if let Some(envelope) = envelope.downcast_ref::<TypedEnvelope<proto::Ping>>() {
440 let receipt = envelope.receipt();
441 peer.respond(
442 receipt,
443 proto::Pong {
444 id: envelope.payload.id,
445 },
446 )
447 .await?
448 } else if let Some(envelope) =
449 envelope.downcast_ref::<TypedEnvelope<proto::OpenBuffer>>()
450 {
451 let message = &envelope.payload;
452 let receipt = envelope.receipt();
453 let response = match message.path.as_str() {
454 "path/one" => {
455 assert_eq!(message.worktree_id, 1);
456 proto::OpenBufferResponse {
457 buffer: Some(proto::Buffer {
458 id: 101,
459 content: "path/one content".to_string(),
460 history: vec![],
461 selections: vec![],
462 }),
463 }
464 }
465 "path/two" => {
466 assert_eq!(message.worktree_id, 2);
467 proto::OpenBufferResponse {
468 buffer: Some(proto::Buffer {
469 id: 102,
470 content: "path/two content".to_string(),
471 history: vec![],
472 selections: vec![],
473 }),
474 }
475 }
476 _ => {
477 panic!("unexpected path {}", message.path);
478 }
479 };
480
481 peer.respond(receipt, response).await?
482 } else {
483 panic!("unknown message type");
484 }
485 }
486
487 Ok(())
488 }
489 });
490 }
491
492 #[test]
493 fn test_disconnect() {
494 smol::block_on(async move {
495 let (client_conn, mut server_conn) = test::Channel::bidirectional();
496
497 let client = Peer::new();
498 let (connection_id, io_handler, mut incoming) =
499 client.add_connection(client_conn).await;
500
501 let (mut io_ended_tx, mut io_ended_rx) = postage::barrier::channel();
502 smol::spawn(async move {
503 io_handler.await.ok();
504 io_ended_tx.send(()).await.unwrap();
505 })
506 .detach();
507
508 let (mut messages_ended_tx, mut messages_ended_rx) = postage::barrier::channel();
509 smol::spawn(async move {
510 incoming.next().await;
511 messages_ended_tx.send(()).await.unwrap();
512 })
513 .detach();
514
515 client.disconnect(connection_id).await;
516
517 io_ended_rx.recv().await;
518 messages_ended_rx.recv().await;
519 assert!(
520 futures::SinkExt::send(&mut server_conn, WebSocketMessage::Binary(vec![]))
521 .await
522 .is_err()
523 );
524 });
525 }
526
527 #[test]
528 fn test_io_error() {
529 smol::block_on(async move {
530 let (client_conn, server_conn) = test::Channel::bidirectional();
531 drop(server_conn);
532
533 let client = Peer::new();
534 let (connection_id, io_handler, mut incoming) =
535 client.add_connection(client_conn).await;
536 smol::spawn(io_handler).detach();
537 smol::spawn(async move { incoming.next().await }).detach();
538
539 let err = client
540 .request(connection_id, proto::Ping { id: 42 })
541 .await
542 .unwrap_err();
543 assert_eq!(err.to_string(), "connection was closed");
544 });
545 }
546}