aboutsummaryrefslogtreecommitdiff
path: root/helix-lsp/src/transport.rs
blob: 0710b449c9a94d2c1b0436915ce7234e63f03223 (plain) (blame)
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
262
263
use crate::Result;
use anyhow::Context;
use jsonrpc_core as jsonrpc;
use log::{error, info};
use serde::{Deserialize, Serialize};
use serde_json::Value;
use std::collections::HashMap;
use std::sync::Arc;
use tokio::{
    io::{AsyncBufRead, AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader, BufWriter},
    process::{ChildStderr, ChildStdin, ChildStdout},
    sync::{
        mpsc::{unbounded_channel, Sender, UnboundedReceiver, UnboundedSender},
        Mutex,
    },
};

#[derive(Debug)]
pub enum Payload {
    Request {
        chan: Sender<Result<Value>>,
        value: jsonrpc::MethodCall,
    },
    Notification(jsonrpc::Notification),
    Response(jsonrpc::Output),
}

/// A type representing all possible values sent from the server to the client.
#[derive(Debug, PartialEq, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
#[serde(untagged)]
enum ServerMessage {
    /// A regular JSON-RPC request output (single response).
    Output(jsonrpc::Output),
    /// A JSON-RPC request or notification.
    Call(jsonrpc::Call),
}

#[derive(Debug)]
pub struct Transport {
    id: usize,
    pending_requests: Mutex<HashMap<jsonrpc::Id, Sender<Result<Value>>>>,
}

impl Transport {
    pub fn start(
        server_stdout: BufReader<ChildStdout>,
        server_stdin: BufWriter<ChildStdin>,
        server_stderr: BufReader<ChildStderr>,
        id: usize,
    ) -> (
        UnboundedReceiver<(usize, jsonrpc::Call)>,
        UnboundedSender<Payload>,
    ) {
        let (client_tx, rx) = unbounded_channel();
        let (tx, client_rx) = unbounded_channel();

        let transport = Self {
            id,
            pending_requests: Mutex::new(HashMap::default()),
        };

        let transport = Arc::new(transport);

        tokio::spawn(Self::recv(transport.clone(), server_stdout, client_tx));
        tokio::spawn(Self::err(transport.clone(), server_stderr));
        tokio::spawn(Self::send(transport, server_stdin, client_rx));

        (rx, tx)
    }

    async fn recv_server_message(
        reader: &mut (impl AsyncBufRead + Unpin + Send),
        buffer: &mut String,
    ) -> Result<ServerMessage> {
        let mut content_length = None;
        loop {
            buffer.truncate(0);
            reader.read_line(buffer).await?;
            let header = buffer.trim();

            if header.is_empty() {
                break;
            }

            let mut parts = header.split(": ");

            match (parts.next(), parts.next(), parts.next()) {
                (Some("Content-Length"), Some(value), None) => {
                    content_length = Some(value.parse().context("invalid content length")?);
                }
                (Some(_), Some(_), None) => {}
                _ => {
                    return Err(std::io::Error::new(
                        std::io::ErrorKind::Other,
                        "Failed to parse header",
                    )
                    .into());
                }
            }
        }

        let content_length = content_length.context("missing content length")?;

        //TODO: reuse vector
        let mut content = vec![0; content_length];
        reader.read_exact(&mut content).await?;
        let msg = std::str::from_utf8(&content).context("invalid utf8 from server")?;

        info!("<- {}", msg);

        // try parsing as output (server response) or call (server request)
        let output: serde_json::Result<ServerMessage> = serde_json::from_str(msg);

        Ok(output?)
    }

    async fn recv_server_error(
        err: &mut (impl AsyncBufRead + Unpin + Send),
        buffer: &mut String,
    ) -> Result<()> {
        buffer.truncate(0);
        err.read_line(buffer).await?;
        error!("err <- {}", buffer);

        Ok(())
    }

    async fn send_payload_to_server(
        &self,
        server_stdin: &mut BufWriter<ChildStdin>,
        payload: Payload,
    ) -> Result<()> {
        //TODO: reuse string
        let json = match payload {
            Payload::Request { chan, value } => {
                self.pending_requests
                    .lock()
                    .await
                    .insert(value.id.clone(), chan);
                serde_json::to_string(&value)?
            }
            Payload::Notification(value) => serde_json::to_string(&value)?,
            Payload::Response(error) => serde_json::to_string(&error)?,
        };
        self.send_string_to_server(server_stdin, json).await
    }

    async fn send_string_to_server(
        &self,
        server_stdin: &mut BufWriter<ChildStdin>,
        request: String,
    ) -> Result<()> {
        info!("-> {}", request);

        // send the headers
        server_stdin
            .write_all(format!("Content-Length: {}\r\n\r\n", request.len()).as_bytes())
            .await?;

        // send the body
        server_stdin.write_all(request.as_bytes()).await?;

        server_stdin.flush().await?;

        Ok(())
    }

    async fn process_server_message(
        &self,
        client_tx: &UnboundedSender<(usize, jsonrpc::Call)>,
        msg: ServerMessage,
    ) -> Result<()> {
        match msg {
            ServerMessage::Output(output) => self.process_request_response(output).await?,
            ServerMessage::Call(call) => {
                client_tx
                    .send((self.id, call))
                    .context("failed to send a message to server")?;
                // let notification = Notification::parse(&method, params);
            }
        };
        Ok(())
    }

    async fn process_request_response(&self, output: jsonrpc::Output) -> Result<()> {
        let (id, result) = match output {
            jsonrpc::Output::Success(jsonrpc::Success { id, result, .. }) => {
                info!("<- {}", result);
                (id, Ok(result))
            }
            jsonrpc::Output::Failure(jsonrpc::Failure { id, error, .. }) => {
                error!("<- {}", error);
                (id, Err(error.into()))
            }
        };

        let tx = self
            .pending_requests
            .lock()
            .await
            .remove(&id)
            .expect("pending_request with id not found!");

        match tx.send(result).await {
            Ok(_) => (),
            Err(_) => error!(
                "Tried sending response into a closed channel (id={:?}), original request likely timed out",
                id
            ),
        };

        Ok(())
    }

    async fn recv(
        transport: Arc<Self>,
        mut server_stdout: BufReader<ChildStdout>,
        client_tx: UnboundedSender<(usize, jsonrpc::Call)>,
    ) {
        let mut recv_buffer = String::new();
        loop {
            match Self::recv_server_message(&mut server_stdout, &mut recv_buffer).await {
                Ok(msg) => {
                    transport
                        .process_server_message(&client_tx, msg)
                        .await
                        .unwrap();
                }
                Err(err) => {
                    error!("err: <- {:?}", err);
                    break;
                }
            }
        }
    }

    async fn err(_transport: Arc<Self>, mut server_stderr: BufReader<ChildStderr>) {
        let mut recv_buffer = String::new();
        loop {
            match Self::recv_server_error(&mut server_stderr, &mut recv_buffer).await {
                Ok(_) => {}
                Err(err) => {
                    error!("err: <- {:?}", err);
                    break;
                }
            }
        }
    }

    async fn send(
        transport: Arc<Self>,
        mut server_stdin: BufWriter<ChildStdin>,
        mut client_rx: UnboundedReceiver<Payload>,
    ) {
        while let Some(msg) = client_rx.recv().await {
            transport
                .send_payload_to_server(&mut server_stdin, msg)
                .await
                .unwrap()
        }
    }
}