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
use crate::io::blocking::Blocking;
use crate::io::stdio_common::SplitByUtf8BoundaryIfWindows;
use crate::io::AsyncWrite;
use std::io;
use std::pin::Pin;
use std::task::Context;
use std::task::Poll;
cfg_io_std! {
/// A handle to the standard output stream of a process.
///
/// Concurrent writes to stdout must be executed with care: Only individual
/// writes to this [`AsyncWrite`] are guaranteed to be intact. In particular
/// you should be aware that writes using [`write_all`] are not guaranteed
/// to occur as a single write, so multiple threads writing data with
/// [`write_all`] may result in interleaved output.
///
/// Created by the [`stdout`] function.
///
/// [`stdout`]: stdout()
/// [`AsyncWrite`]: AsyncWrite
/// [`write_all`]: crate::io::AsyncWriteExt::write_all()
///
/// # Examples
///
/// ```
/// use tokio::io::{self, AsyncWriteExt};
///
/// #[tokio::main]
/// async fn main() -> io::Result<()> {
/// let mut stdout = io::stdout();
/// stdout.write_all(b"Hello world!").await?;
/// Ok(())
/// }
/// ```
///
/// The following is an example of using `stdio` with loop.
///
/// ```
/// use tokio::io::{self, AsyncWriteExt};
///
/// #[tokio::main]
/// async fn main() {
/// let messages = vec!["hello", " world\n"];
///
/// // When you use `stdio` in a loop, it is recommended to create
/// // a single `stdio` instance outside the loop and call a write
/// // operation against that instance on each loop.
/// //
/// // Repeatedly creating `stdout` instances inside the loop and
/// // writing to that handle could result in mangled output since
/// // each write operation is handled by a different blocking thread.
/// let mut stdout = io::stdout();
///
/// for message in &messages {
/// stdout.write_all(message.as_bytes()).await.unwrap();
/// stdout.flush().await.unwrap();
/// }
/// }
/// ```
#[derive(Debug)]
pub struct Stdout {
std: SplitByUtf8BoundaryIfWindows<Blocking<std::io::Stdout>>,
}
/// Constructs a new handle to the standard output of the current process.
///
/// The returned handle allows writing to standard out from the within the
/// Tokio runtime.
///
/// Concurrent writes to stdout must be executed with care: Only individual
/// writes to this [`AsyncWrite`] are guaranteed to be intact. In particular
/// you should be aware that writes using [`write_all`] are not guaranteed
/// to occur as a single write, so multiple threads writing data with
/// [`write_all`] may result in interleaved output.
///
/// [`AsyncWrite`]: AsyncWrite
/// [`write_all`]: crate::io::AsyncWriteExt::write_all()
///
/// # Examples
///
/// ```
/// use tokio::io::{self, AsyncWriteExt};
///
/// #[tokio::main]
/// async fn main() -> io::Result<()> {
/// let mut stdout = io::stdout();
/// stdout.write_all(b"Hello world!").await?;
/// Ok(())
/// }
/// ```
///
/// The following is an example of using `stdio` with loop.
///
/// ```
/// use tokio::io::{self, AsyncWriteExt};
///
/// #[tokio::main]
/// async fn main() {
/// let messages = vec!["hello", " world\n"];
///
/// // When you use `stdio` in a loop, it is recommended to create
/// // a single `stdio` instance outside the loop and call a write
/// // operation against that instance on each loop.
/// //
/// // Repeatedly creating `stdout` instances inside the loop and
/// // writing to that handle could result in mangled output since
/// // each write operation is handled by a different blocking thread.
/// let mut stdout = io::stdout();
///
/// for message in &messages {
/// stdout.write_all(message.as_bytes()).await.unwrap();
/// stdout.flush().await.unwrap();
/// }
/// }
/// ```
pub fn stdout() -> Stdout {
let std = io::stdout();
Stdout {
std: SplitByUtf8BoundaryIfWindows::new(Blocking::new(std)),
}
}
}
#[cfg(unix)]
mod sys {
use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
use super::Stdout;
impl AsRawFd for Stdout {
fn as_raw_fd(&self) -> RawFd {
std::io::stdout().as_raw_fd()
}
}
impl AsFd for Stdout {
fn as_fd(&self) -> BorrowedFd<'_> {
unsafe { BorrowedFd::borrow_raw(self.as_raw_fd()) }
}
}
}
cfg_windows! {
use crate::os::windows::io::{AsHandle, BorrowedHandle, AsRawHandle, RawHandle};
impl AsRawHandle for Stdout {
fn as_raw_handle(&self) -> RawHandle {
std::io::stdout().as_raw_handle()
}
}
impl AsHandle for Stdout {
fn as_handle(&self) -> BorrowedHandle<'_> {
unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
}
}
}
impl AsyncWrite for Stdout {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.std).poll_write(cx, buf)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
Pin::new(&mut self.std).poll_flush(cx)
}
fn poll_shutdown(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<(), io::Error>> {
Pin::new(&mut self.std).poll_shutdown(cx)
}
}