1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
use std::{
cell::{Cell, RefCell},
rc::Rc,
};
use async_trait::async_trait;
use futures::{channel::mpsc, prelude::stream::LocalBoxStream};
use medea_client_api_proto::{ClientMsg, ServerMsg};
use medea_macro::dart_bridge;
use medea_reactive::ObservableCell;
use tracerr::Traced;
use crate::{
platform::{
RpcTransport, TransportError, TransportState,
dart::utils::{
callback::Callback, dart_future::FutureFromDart,
dart_string_into_rust, handle::DartHandle, string_into_c_str,
},
},
rpc::{ApiUrl, ClientDisconnect, CloseMsg},
};
type TransportResult<T> = Result<T, Traced<TransportError>>;
#[dart_bridge("flutter/lib/src/native/platform/transport.g.dart")]
mod transport {
use std::{os::raw::c_char, ptr};
use dart_sys::Dart_Handle;
use crate::platform::Error;
extern "C" {
/// [Connects][1] to the provided `url` and returns the created
/// [`WebSocket`][0].
///
/// [Subscribes][2] to the created [`WebSocket`][0] passing the given
/// `on_message` and `on_close` callbacks.
///
/// [0]: https://api.dart.dev/stable/dart-io/WebSocket-class.html
/// [1]: https://api.dart.dev/stable/dart-io/WebSocket/connect.html
/// [2]: https://api.dart.dev/stable/dart-async/Stream/listen.html
pub fn connect(
url: ptr::NonNull<c_char>,
on_message: Dart_Handle,
on_close: Dart_Handle,
) -> Result<Dart_Handle, Error>;
/// [Sends][1] the provided `message` via the provided [`WebSocket`][0].
///
/// [0]: https://api.dart.dev/stable/dart-io/WebSocket-class.html
/// [1]: https://api.dart.dev/stable/dart-io/WebSocket/add.html
pub fn send(
transport: Dart_Handle,
message: ptr::NonNull<c_char>,
) -> Result<(), Error>;
/// [Closes][1] the provided [`WebSocket`][0] connection.
///
/// [0]: https://api.dart.dev/stable/dart-io/WebSocket-class.html
/// [1]: https://api.dart.dev/stable/dart-io/WebSocket/close.html
pub fn close(
transport: Dart_Handle,
close_code: i32,
close_msg: ptr::NonNull<c_char>,
) -> Result<(), Error>;
/// Returns the [closeCode][0] of the [close frame][1].
///
/// [0]: https://api.dart.dev/stable/dart-io/WebSocket/closeCode.html
/// [1]: https://tools.ietf.org/html/rfc6455#section-5.5.1
pub fn close_code(close_frame: Dart_Handle) -> Result<i32, Error>;
/// Returns the [closeReason][0] of the [close frame][1].
///
/// [0]: https://api.dart.dev/stable/dart-io/WebSocket/closeReason.html
/// [1]: https://tools.ietf.org/html/rfc6455#section-5.5.1
pub fn close_reason(
close_frame: Dart_Handle,
) -> Result<ptr::NonNull<c_char>, Error>;
}
}
/// [`RpcTransport`] implementation of a Dart side [`WebSocket`][0].
///
/// [0]: https://api.dart.dev/stable/dart-io/WebSocket-class.html
#[derive(Clone, Debug)]
pub struct WebSocketRpcTransport {
/// Handle to the Dart side [`WebSocket`][0].
///
/// If [`DartHandle`] is [`None`], then connection hasn't been instantiated
/// yet.
///
/// [0]: https://api.dart.dev/stable/dart-io/WebSocket-class.html
handle: RefCell<Option<DartHandle>>,
/// Subscribers to the messages received by this transport.
on_message_subs: Rc<RefCell<Vec<mpsc::UnboundedSender<ServerMsg>>>>,
/// Reason of [`WebSocketRpcTransport`] closing.
///
/// Is sent in a [WebSocket close frame][1].
///
/// [1]: https://tools.ietf.org/html/rfc6455#section-5.5.1
close_reason: Cell<ClientDisconnect>,
/// State of this [`WebSocketRpcTransport`] connection.
socket_state: Rc<ObservableCell<TransportState>>,
}
impl WebSocketRpcTransport {
/// Creates a new [`WebSocketRpcTransport`] which can be connected to the
/// server with the [`RpcTransport::connect()`] method call.
#[must_use]
pub fn new() -> Self {
Self {
handle: RefCell::new(None),
on_message_subs: Rc::new(RefCell::new(Vec::new())),
socket_state: Rc::new(ObservableCell::new(
TransportState::Connecting,
)),
close_reason: Cell::new(
ClientDisconnect::RpcTransportUnexpectedlyDropped,
),
}
}
}
impl Default for WebSocketRpcTransport {
fn default() -> Self {
Self::new()
}
}
#[async_trait(?Send)]
impl RpcTransport for WebSocketRpcTransport {
async fn connect(&self, url: ApiUrl) -> TransportResult<()> {
// TODO: Propagate execution error.
#[expect(clippy::map_err_ignore, reason = "needs refactoring")]
let handle = {
let on_message = Callback::from_fn_mut({
let weak_subs = Rc::downgrade(&self.on_message_subs);
move |msg: String| {
if let Some(subs) = weak_subs.upgrade() {
let msg = match serde_json::from_str::<ServerMsg>(&msg)
{
Ok(parsed) => parsed,
Err(e) => {
// TODO: Protocol versions mismatch?
// Should drop connection if so.
log::error!("{}", tracerr::new!(e));
return;
}
};
subs.borrow_mut().retain(
|sub: &mpsc::UnboundedSender<ServerMsg>| {
sub.unbounded_send(msg.clone()).is_ok()
},
);
}
}
})
.into_dart();
let on_close = Callback::from_fn_mut({
let socket_state = Rc::clone(&self.socket_state);
move |close_frame: DartHandle| {
let code =
unsafe { transport::close_code(close_frame.get()) }
.unwrap()
.try_into()
.unwrap_or(1007);
let reason =
unsafe { transport::close_reason(close_frame.get()) }
.unwrap();
let reason = unsafe { dart_string_into_rust(reason) };
socket_state.set(TransportState::Closed(CloseMsg::from((
code, reason,
))));
}
})
.into_dart();
let fut = unsafe {
transport::connect(
string_into_c_str(url.as_ref().to_owned()),
on_message,
on_close,
)
}
.unwrap();
unsafe { FutureFromDart::execute::<DartHandle>(fut) }
}
.await
.map_err(|_| tracerr::new!(TransportError::InitSocket))?;
*self.handle.borrow_mut() = Some(handle);
self.socket_state.set(TransportState::Open);
Ok(())
}
fn on_message(&self) -> LocalBoxStream<'static, ServerMsg> {
let (tx, rx) = mpsc::unbounded();
self.on_message_subs.borrow_mut().push(tx);
Box::pin(rx)
}
fn set_close_reason(&self, reason: ClientDisconnect) {
self.close_reason.set(reason);
}
#[expect(clippy::unwrap_in_result, reason = "unrelated")]
fn send(&self, msg: &ClientMsg) -> TransportResult<()> {
let state = self.socket_state.get();
let handle = self
.handle
.borrow()
.as_ref()
.cloned()
.ok_or_else(|| tracerr::new!(TransportError::ClosedSocket))?;
match state {
TransportState::Open => unsafe {
let msg = serde_json::to_string(msg).unwrap();
transport::send(handle.get(), string_into_c_str(msg))
.map_err(TransportError::SendMessage)
.map_err(tracerr::wrap!())?;
Ok(())
},
TransportState::Connecting
| TransportState::Closing
| TransportState::Closed(_) => {
Err(tracerr::new!(TransportError::ClosedSocket))
}
}
}
fn on_state_change(&self) -> LocalBoxStream<'static, TransportState> {
self.socket_state.subscribe()
}
}
impl Drop for WebSocketRpcTransport {
fn drop(&mut self) {
let code = self.close_reason.get().code();
let rsn = serde_json::to_string(&self.close_reason.get())
.unwrap_or_else(|e| panic!("cannot serialize close message: {e}"));
if let Some(handle) = self.handle.borrow().as_ref() {
unsafe {
transport::close(
handle.get(),
code.into(),
string_into_c_str(rsn),
)
}
.unwrap();
}
}
}