aboutsummaryrefslogtreecommitdiff
path: root/crates/flycheck/src/lib.rs
blob: ad376ad18585d493e94e67db6563aa4e96fb8a7e (plain)
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
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
//! cargo_check provides the functionality needed to run `cargo check` or
//! another compatible command (f.x. clippy) in a background thread and provide
//! LSP diagnostics based on the output of the command.

use std::{
    fmt,
    io::{self, BufReader},
    ops,
    path::PathBuf,
    process::{self, Command, Stdio},
    time::Duration,
};

use crossbeam_channel::{never, select, unbounded, Receiver, Sender};

pub use cargo_metadata::diagnostic::{
    Applicability, Diagnostic, DiagnosticCode, DiagnosticLevel, DiagnosticSpan,
    DiagnosticSpanMacroExpansion,
};

#[derive(Clone, Debug, PartialEq, Eq)]
pub enum FlycheckConfig {
    CargoCommand {
        command: String,
        target_triple: Option<String>,
        all_targets: bool,
        all_features: bool,
        features: Vec<String>,
        extra_args: Vec<String>,
    },
    CustomCommand {
        command: String,
        args: Vec<String>,
    },
}

impl fmt::Display for FlycheckConfig {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            FlycheckConfig::CargoCommand { command, .. } => write!(f, "cargo {}", command),
            FlycheckConfig::CustomCommand { command, args } => {
                write!(f, "{} {}", command, args.join(" "))
            }
        }
    }
}

/// Flycheck wraps the shared state and communication machinery used for
/// running `cargo check` (or other compatible command) and providing
/// diagnostics based on the output.
/// The spawned thread is shut down when this struct is dropped.
#[derive(Debug)]
pub struct FlycheckHandle {
    // XXX: drop order is significant
    sender: Sender<Restart>,
    thread: jod_thread::JoinHandle,
}

impl FlycheckHandle {
    pub fn spawn(
        sender: Box<dyn Fn(Message) + Send>,
        config: FlycheckConfig,
        workspace_root: PathBuf,
    ) -> FlycheckHandle {
        let actor = FlycheckActor::new(sender, config, workspace_root);
        let (sender, receiver) = unbounded::<Restart>();
        let thread = jod_thread::spawn(move || actor.run(receiver));
        FlycheckHandle { sender, thread }
    }

    /// Schedule a re-start of the cargo check worker.
    pub fn update(&self) {
        self.sender.send(Restart).unwrap();
    }
}

#[derive(Debug)]
pub enum Message {
    /// Request adding a diagnostic with fixes included to a file
    AddDiagnostic { workspace_root: PathBuf, diagnostic: Diagnostic },

    /// Request check progress notification to client
    Progress(Progress),
}

#[derive(Debug)]
pub enum Progress {
    DidStart,
    DidCheckCrate(String),
    DidFinish(io::Result<()>),
    DidCancel,
}

struct Restart;

struct FlycheckActor {
    sender: Box<dyn Fn(Message) + Send>,
    config: FlycheckConfig,
    workspace_root: PathBuf,
    /// WatchThread exists to wrap around the communication needed to be able to
    /// run `cargo check` without blocking. Currently the Rust standard library
    /// doesn't provide a way to read sub-process output without blocking, so we
    /// have to wrap sub-processes output handling in a thread and pass messages
    /// back over a channel.
    cargo_handle: Option<CargoHandle>,
}

enum Event {
    Restart(Restart),
    CheckEvent(Option<cargo_metadata::Message>),
}

impl FlycheckActor {
    fn new(
        sender: Box<dyn Fn(Message) + Send>,
        config: FlycheckConfig,
        workspace_root: PathBuf,
    ) -> FlycheckActor {
        FlycheckActor { sender, config, workspace_root, cargo_handle: None }
    }
    fn next_event(&self, inbox: &Receiver<Restart>) -> Option<Event> {
        let check_chan = self.cargo_handle.as_ref().map(|cargo| &cargo.receiver);
        select! {
            recv(inbox) -> msg => msg.ok().map(Event::Restart),
            recv(check_chan.unwrap_or(&never())) -> msg => Some(Event::CheckEvent(msg.ok())),
        }
    }
    fn run(mut self, inbox: Receiver<Restart>) {
        while let Some(event) = self.next_event(&inbox) {
            match event {
                Event::Restart(Restart) => {
                    while let Ok(Restart) = inbox.recv_timeout(Duration::from_millis(50)) {}

                    self.cancel_check_process();

                    let mut command = self.check_command();
                    log::info!("restart flycheck {:?}", command);
                    command.stdout(Stdio::piped()).stderr(Stdio::null()).stdin(Stdio::null());
                    if let Ok(child) = command.spawn().map(JodChild) {
                        self.cargo_handle = Some(CargoHandle::spawn(child));
                        self.send(Message::Progress(Progress::DidStart));
                    }
                }
                Event::CheckEvent(None) => {
                    // Watcher finished, replace it with a never channel to
                    // avoid busy-waiting.
                    let cargo_handle = self.cargo_handle.take().unwrap();
                    let res = cargo_handle.join();
                    self.send(Message::Progress(Progress::DidFinish(res)));
                }
                Event::CheckEvent(Some(message)) => match message {
                    cargo_metadata::Message::CompilerArtifact(msg) => {
                        self.send(Message::Progress(Progress::DidCheckCrate(msg.target.name)));
                    }

                    cargo_metadata::Message::CompilerMessage(msg) => {
                        self.send(Message::AddDiagnostic {
                            workspace_root: self.workspace_root.clone(),
                            diagnostic: msg.message,
                        });
                    }

                    cargo_metadata::Message::BuildScriptExecuted(_)
                    | cargo_metadata::Message::BuildFinished(_)
                    | cargo_metadata::Message::TextLine(_)
                    | cargo_metadata::Message::Unknown => {}
                },
            }
        }
        // If we rerun the thread, we need to discard the previous check results first
        self.cancel_check_process();
    }
    fn cancel_check_process(&mut self) {
        if self.cargo_handle.take().is_some() {
            self.send(Message::Progress(Progress::DidCancel));
        }
    }
    fn check_command(&self) -> Command {
        let mut cmd = match &self.config {
            FlycheckConfig::CargoCommand {
                command,
                target_triple,
                all_targets,
                all_features,
                extra_args,
                features,
            } => {
                let mut cmd = Command::new(ra_toolchain::cargo());
                cmd.arg(command);
                cmd.args(&["--workspace", "--message-format=json", "--manifest-path"])
                    .arg(self.workspace_root.join("Cargo.toml"));

                if let Some(target) = target_triple {
                    cmd.args(&["--target", target.as_str()]);
                }
                if *all_targets {
                    cmd.arg("--all-targets");
                }
                if *all_features {
                    cmd.arg("--all-features");
                } else if !features.is_empty() {
                    cmd.arg("--features");
                    cmd.arg(features.join(" "));
                }
                cmd.args(extra_args);
                cmd
            }
            FlycheckConfig::CustomCommand { command, args } => {
                let mut cmd = Command::new(command);
                cmd.args(args);
                cmd
            }
        };
        cmd.current_dir(&self.workspace_root);
        cmd
    }

    fn send(&self, check_task: Message) {
        (self.sender)(check_task)
    }
}

struct CargoHandle {
    child: JodChild,
    #[allow(unused)]
    thread: jod_thread::JoinHandle<io::Result<bool>>,
    receiver: Receiver<cargo_metadata::Message>,
}

impl CargoHandle {
    fn spawn(mut child: JodChild) -> CargoHandle {
        let child_stdout = child.stdout.take().unwrap();
        let (sender, receiver) = unbounded();
        let actor = CargoActor::new(child_stdout, sender);
        let thread = jod_thread::spawn(move || actor.run());
        CargoHandle { child, thread, receiver }
    }
    fn join(mut self) -> io::Result<()> {
        // It is okay to ignore the result, as it only errors if the process is already dead
        let _ = self.child.kill();
        let exit_status = self.child.wait()?;
        let read_at_least_one_message = self.thread.join()?;
        if !exit_status.success() && !read_at_least_one_message {
            // FIXME: Read the stderr to display the reason, see `read2()` reference in PR comment:
            // https://github.com/rust-analyzer/rust-analyzer/pull/3632#discussion_r395605298
            return Err(io::Error::new(
                io::ErrorKind::Other,
                format!(
                    "Cargo watcher failed,the command produced no valid metadata (exit code: {:?})",
                    exit_status
                ),
            ));
        }
        Ok(())
    }
}

struct CargoActor {
    child_stdout: process::ChildStdout,
    sender: Sender<cargo_metadata::Message>,
}

impl CargoActor {
    fn new(
        child_stdout: process::ChildStdout,
        sender: Sender<cargo_metadata::Message>,
    ) -> CargoActor {
        CargoActor { child_stdout, sender }
    }
    fn run(self) -> io::Result<bool> {
        // We manually read a line at a time, instead of using serde's
        // stream deserializers, because the deserializer cannot recover
        // from an error, resulting in it getting stuck, because we try to
        // be resilient against failures.
        //
        // Because cargo only outputs one JSON object per line, we can
        // simply skip a line if it doesn't parse, which just ignores any
        // erroneus output.
        let stdout = BufReader::new(self.child_stdout);
        let mut read_at_least_one_message = false;
        for message in cargo_metadata::Message::parse_stream(stdout) {
            let message = match message {
                Ok(message) => message,
                Err(err) => {
                    log::error!("Invalid json from cargo check, ignoring ({})", err);
                    continue;
                }
            };

            read_at_least_one_message = true;

            // Skip certain kinds of messages to only spend time on what's useful
            match &message {
                cargo_metadata::Message::CompilerArtifact(artifact) if artifact.fresh => (),
                cargo_metadata::Message::BuildScriptExecuted(_)
                | cargo_metadata::Message::Unknown => (),
                _ => self.sender.send(message).unwrap(),
            }
        }
        Ok(read_at_least_one_message)
    }
}

struct JodChild(process::Child);

impl ops::Deref for JodChild {
    type Target = process::Child;
    fn deref(&self) -> &process::Child {
        &self.0
    }
}

impl ops::DerefMut for JodChild {
    fn deref_mut(&mut self) -> &mut process::Child {
        &mut self.0
    }
}

impl Drop for JodChild {
    fn drop(&mut self) {
        let _ = self.0.kill();
    }
}