madsim_real_tokio/io/
stdout.rs

1use crate::io::blocking::Blocking;
2use crate::io::stdio_common::SplitByUtf8BoundaryIfWindows;
3use crate::io::AsyncWrite;
4use std::io;
5use std::pin::Pin;
6use std::task::Context;
7use std::task::Poll;
8
9cfg_io_std! {
10    /// A handle to the standard output stream of a process.
11    ///
12    /// Concurrent writes to stdout must be executed with care: Only individual
13    /// writes to this [`AsyncWrite`] are guaranteed to be intact. In particular
14    /// you should be aware that writes using [`write_all`] are not guaranteed
15    /// to occur as a single write, so multiple threads writing data with
16    /// [`write_all`] may result in interleaved output.
17    ///
18    /// Created by the [`stdout`] function.
19    ///
20    /// [`stdout`]: stdout()
21    /// [`AsyncWrite`]: AsyncWrite
22    /// [`write_all`]: crate::io::AsyncWriteExt::write_all()
23    ///
24    /// # Examples
25    ///
26    /// ```
27    /// use tokio::io::{self, AsyncWriteExt};
28    ///
29    /// #[tokio::main]
30    /// async fn main() -> io::Result<()> {
31    ///     let mut stdout = io::stdout();
32    ///     stdout.write_all(b"Hello world!").await?;
33    ///     Ok(())
34    /// }
35    /// ```
36    #[derive(Debug)]
37    pub struct Stdout {
38        std: SplitByUtf8BoundaryIfWindows<Blocking<std::io::Stdout>>,
39    }
40
41    /// Constructs a new handle to the standard output of the current process.
42    ///
43    /// The returned handle allows writing to standard out from the within the
44    /// Tokio runtime.
45    ///
46    /// Concurrent writes to stdout must be executed with care: Only individual
47    /// writes to this [`AsyncWrite`] are guaranteed to be intact. In particular
48    /// you should be aware that writes using [`write_all`] are not guaranteed
49    /// to occur as a single write, so multiple threads writing data with
50    /// [`write_all`] may result in interleaved output.
51    ///
52    /// [`AsyncWrite`]: AsyncWrite
53    /// [`write_all`]: crate::io::AsyncWriteExt::write_all()
54    ///
55    /// # Examples
56    ///
57    /// ```
58    /// use tokio::io::{self, AsyncWriteExt};
59    ///
60    /// #[tokio::main]
61    /// async fn main() -> io::Result<()> {
62    ///     let mut stdout = io::stdout();
63    ///     stdout.write_all(b"Hello world!").await?;
64    ///     Ok(())
65    /// }
66    /// ```
67    pub fn stdout() -> Stdout {
68        let std = io::stdout();
69        Stdout {
70            std: SplitByUtf8BoundaryIfWindows::new(Blocking::new(std)),
71        }
72    }
73}
74
75#[cfg(unix)]
76mod sys {
77    use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
78
79    use super::Stdout;
80
81    impl AsRawFd for Stdout {
82        fn as_raw_fd(&self) -> RawFd {
83            std::io::stdout().as_raw_fd()
84        }
85    }
86
87    impl AsFd for Stdout {
88        fn as_fd(&self) -> BorrowedFd<'_> {
89            unsafe { BorrowedFd::borrow_raw(self.as_raw_fd()) }
90        }
91    }
92}
93
94cfg_windows! {
95    use crate::os::windows::io::{AsHandle, BorrowedHandle, AsRawHandle, RawHandle};
96
97    impl AsRawHandle for Stdout {
98        fn as_raw_handle(&self) -> RawHandle {
99            std::io::stdout().as_raw_handle()
100        }
101    }
102
103    impl AsHandle for Stdout {
104        fn as_handle(&self) -> BorrowedHandle<'_> {
105            unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
106        }
107    }
108}
109
110impl AsyncWrite for Stdout {
111    fn poll_write(
112        mut self: Pin<&mut Self>,
113        cx: &mut Context<'_>,
114        buf: &[u8],
115    ) -> Poll<io::Result<usize>> {
116        Pin::new(&mut self.std).poll_write(cx, buf)
117    }
118
119    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
120        Pin::new(&mut self.std).poll_flush(cx)
121    }
122
123    fn poll_shutdown(
124        mut self: Pin<&mut Self>,
125        cx: &mut Context<'_>,
126    ) -> Poll<Result<(), io::Error>> {
127        Pin::new(&mut self.std).poll_shutdown(cx)
128    }
129}
madsim_real_tokio/io/stdout.rs

madsim_real_tokio/io/
stdout.rs
