aboutsummaryrefslogtreecommitdiff
path: root/crates/stdx/src/process.rs
blob: b290ba2f058272ce0f2ffd940251c8ecd975eb0c (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
//! Read both stdout and stderr of child without deadlocks.
//!
//! <https://github.com/rust-lang/cargo/blob/905af549966f23a9288e9993a85d1249a5436556/crates/cargo-util/src/read2.rs>
//! <https://github.com/rust-lang/cargo/blob/58a961314437258065e23cb6316dfc121d96fb71/crates/cargo-util/src/process_builder.rs#L231>

use std::{
    io,
    process::{Command, Output, Stdio},
};

pub fn streaming_output(
    mut cmd: Command,
    on_stdout_line: &mut dyn FnMut(&str),
    on_stderr_line: &mut dyn FnMut(&str),
) -> io::Result<Output> {
    let mut stdout = Vec::new();
    let mut stderr = Vec::new();

    let cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped()).stdin(Stdio::null());

    let status = {
        let mut child = cmd.spawn()?;
        let out = child.stdout.take().unwrap();
        let err = child.stderr.take().unwrap();
        imp::read2(out, err, &mut |is_out, data, eof| {
            let idx = if eof {
                data.len()
            } else {
                match data.iter().rposition(|b| *b == b'\n') {
                    Some(i) => i + 1,
                    None => return,
                }
            };
            {
                // scope for new_lines
                let new_lines = {
                    let dst = if is_out { &mut stdout } else { &mut stderr };
                    let start = dst.len();
                    let data = data.drain(..idx);
                    dst.extend(data);
                    &dst[start..]
                };
                for line in String::from_utf8_lossy(new_lines).lines() {
                    if is_out {
                        on_stdout_line(line)
                    } else {
                        on_stderr_line(line)
                    }
                }
            }
        })?;
        child.wait()?
    };

    Ok(Output { status, stdout, stderr })
}

#[cfg(unix)]
mod imp {
    use std::{
        io::{self, prelude::*},
        mem,
        os::unix::prelude::*,
        process::{ChildStderr, ChildStdout},
    };

    pub(crate) fn read2(
        mut out_pipe: ChildStdout,
        mut err_pipe: ChildStderr,
        data: &mut dyn FnMut(bool, &mut Vec<u8>, bool),
    ) -> io::Result<()> {
        unsafe {
            libc::fcntl(out_pipe.as_raw_fd(), libc::F_SETFL, libc::O_NONBLOCK);
            libc::fcntl(err_pipe.as_raw_fd(), libc::F_SETFL, libc::O_NONBLOCK);
        }

        let mut out_done = false;
        let mut err_done = false;
        let mut out = Vec::new();
        let mut err = Vec::new();

        let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() };
        fds[0].fd = out_pipe.as_raw_fd();
        fds[0].events = libc::POLLIN;
        fds[1].fd = err_pipe.as_raw_fd();
        fds[1].events = libc::POLLIN;
        let mut nfds = 2;
        let mut errfd = 1;

        while nfds > 0 {
            // wait for either pipe to become readable using `select`
            let r = unsafe { libc::poll(fds.as_mut_ptr(), nfds, -1) };
            if r == -1 {
                let err = io::Error::last_os_error();
                if err.kind() == io::ErrorKind::Interrupted {
                    continue;
                }
                return Err(err);
            }

            // Read as much as we can from each pipe, ignoring EWOULDBLOCK or
            // EAGAIN. If we hit EOF, then this will happen because the underlying
            // reader will return Ok(0), in which case we'll see `Ok` ourselves. In
            // this case we flip the other fd back into blocking mode and read
            // whatever's leftover on that file descriptor.
            let handle = |res: io::Result<_>| match res {
                Ok(_) => Ok(true),
                Err(e) => {
                    if e.kind() == io::ErrorKind::WouldBlock {
                        Ok(false)
                    } else {
                        Err(e)
                    }
                }
            };
            if !err_done && fds[errfd].revents != 0 && handle(err_pipe.read_to_end(&mut err))? {
                err_done = true;
                nfds -= 1;
            }
            data(false, &mut err, err_done);
            if !out_done && fds[0].revents != 0 && handle(out_pipe.read_to_end(&mut out))? {
                out_done = true;
                fds[0].fd = err_pipe.as_raw_fd();
                errfd = 0;
                nfds -= 1;
            }
            data(true, &mut out, out_done);
        }
        Ok(())
    }
}

#[cfg(windows)]
mod imp {
    use std::{
        io,
        os::windows::prelude::*,
        process::{ChildStderr, ChildStdout},
        slice,
    };

    use miow::{
        iocp::{CompletionPort, CompletionStatus},
        pipe::NamedPipe,
        Overlapped,
    };
    use winapi::shared::winerror::ERROR_BROKEN_PIPE;

    struct Pipe<'a> {
        dst: &'a mut Vec<u8>,
        overlapped: Overlapped,
        pipe: NamedPipe,
        done: bool,
    }

    pub(crate) fn read2(
        out_pipe: ChildStdout,
        err_pipe: ChildStderr,
        data: &mut dyn FnMut(bool, &mut Vec<u8>, bool),
    ) -> io::Result<()> {
        let mut out = Vec::new();
        let mut err = Vec::new();

        let port = CompletionPort::new(1)?;
        port.add_handle(0, &out_pipe)?;
        port.add_handle(1, &err_pipe)?;

        unsafe {
            let mut out_pipe = Pipe::new(out_pipe, &mut out);
            let mut err_pipe = Pipe::new(err_pipe, &mut err);

            out_pipe.read()?;
            err_pipe.read()?;

            let mut status = [CompletionStatus::zero(), CompletionStatus::zero()];

            while !out_pipe.done || !err_pipe.done {
                for status in port.get_many(&mut status, None)? {
                    if status.token() == 0 {
                        out_pipe.complete(status);
                        data(true, out_pipe.dst, out_pipe.done);
                        out_pipe.read()?;
                    } else {
                        err_pipe.complete(status);
                        data(false, err_pipe.dst, err_pipe.done);
                        err_pipe.read()?;
                    }
                }
            }

            Ok(())
        }
    }

    impl<'a> Pipe<'a> {
        unsafe fn new<P: IntoRawHandle>(p: P, dst: &'a mut Vec<u8>) -> Pipe<'a> {
            Pipe {
                dst,
                pipe: NamedPipe::from_raw_handle(p.into_raw_handle()),
                overlapped: Overlapped::zero(),
                done: false,
            }
        }

        unsafe fn read(&mut self) -> io::Result<()> {
            let dst = slice_to_end(self.dst);
            match self.pipe.read_overlapped(dst, self.overlapped.raw()) {
                Ok(_) => Ok(()),
                Err(e) => {
                    if e.raw_os_error() == Some(ERROR_BROKEN_PIPE as i32) {
                        self.done = true;
                        Ok(())
                    } else {
                        Err(e)
                    }
                }
            }
        }

        unsafe fn complete(&mut self, status: &CompletionStatus) {
            let prev = self.dst.len();
            self.dst.set_len(prev + status.bytes_transferred() as usize);
            if status.bytes_transferred() == 0 {
                self.done = true;
            }
        }
    }

    unsafe fn slice_to_end(v: &mut Vec<u8>) -> &mut [u8] {
        if v.capacity() == 0 {
            v.reserve(16);
        }
        if v.capacity() == v.len() {
            v.reserve(1);
        }
        slice::from_raw_parts_mut(v.as_mut_ptr().add(v.len()), v.capacity() - v.len())
    }
}

#[cfg(target_arch = "wasm32")]
mod imp {
    use std::{
        io,
        process::{ChildStderr, ChildStdout},
    };

    pub(crate) fn read2(
        _out_pipe: ChildStdout,
        _err_pipe: ChildStderr,
        _data: &mut dyn FnMut(bool, &mut Vec<u8>, bool),
    ) -> io::Result<()> {
        panic!("no processes on wasm")
    }
}