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use crate::io::blocking::Blocking;
use crate::io::{AsyncRead, ReadBuf};
use std::io;
use std::pin::Pin;
use std::task::Context;
use std::task::Poll;
cfg_io_std! {
/// A handle to the standard input stream of a process.
///
/// The handle implements the [`AsyncRead`] trait, but beware that concurrent
/// reads of `Stdin` must be executed with care.
///
/// This handle is best used for non-interactive uses, such as when a file
/// is piped into the application. For technical reasons, `stdin` is
/// implemented by using an ordinary blocking read on a separate thread, and
/// it is impossible to cancel that read. This can make shutdown of the
/// runtime hang until the user presses enter.
///
/// For interactive uses, it is recommended to spawn a thread dedicated to
/// user input and use blocking IO directly in that thread.
///
/// Created by the [`stdin`] function.
///
/// [`stdin`]: fn@stdin
/// [`AsyncRead`]: trait@AsyncRead
#[derive(Debug)]
pub struct Stdin {
std: Blocking<std::io::Stdin>,
}
/// Constructs a new handle to the standard input of the current process.
///
/// This handle is best used for non-interactive uses, such as when a file
/// is piped into the application. For technical reasons, `stdin` is
/// implemented by using an ordinary blocking read on a separate thread, and
/// it is impossible to cancel that read. This can make shutdown of the
/// runtime hang until the user presses enter.
///
/// For interactive uses, it is recommended to spawn a thread dedicated to
/// user input and use blocking IO directly in that thread.
pub fn stdin() -> Stdin {
let std = io::stdin();
Stdin {
std: Blocking::new(std),
}
}
}
#[cfg(unix)]
mod sys {
use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
use super::Stdin;
impl AsRawFd for Stdin {
fn as_raw_fd(&self) -> RawFd {
std::io::stdin().as_raw_fd()
}
}
impl AsFd for Stdin {
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 Stdin {
fn as_raw_handle(&self) -> RawHandle {
std::io::stdin().as_raw_handle()
}
}
impl AsHandle for Stdin {
fn as_handle(&self) -> BorrowedHandle<'_> {
unsafe { BorrowedHandle::borrow_raw(self.as_raw_handle()) }
}
}
}
impl AsyncRead for Stdin {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
Pin::new(&mut self.std).poll_read(cx, buf)
}
}