1267 lines
37 KiB
Rust
1267 lines
37 KiB
Rust
//! Async interface for working with processes.
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//!
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//! This crate is an async version of [`std::process`].
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//!
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//! # Implementation
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//!
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//! A background thread named "async-process" is lazily created on first use, which waits for
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//! spawned child processes to exit and then calls the `wait()` syscall to clean up the "zombie"
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//! processes. This is unlike the `process` API in the standard library, where dropping a running
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//! `Child` leaks its resources.
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//!
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//! This crate uses [`async-io`] for async I/O on Unix-like systems and [`blocking`] for async I/O
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//! on Windows.
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//!
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//! [`async-io`]: https://docs.rs/async-io
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//! [`blocking`]: https://docs.rs/blocking
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//!
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//! # Examples
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//!
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//! Spawn a process and collect its output:
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//!
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//! ```no_run
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//! # futures_lite::future::block_on(async {
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//! use async_process::Command;
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//!
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//! let out = Command::new("echo").arg("hello").arg("world").output().await?;
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//! assert_eq!(out.stdout, b"hello world\n");
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//! # std::io::Result::Ok(()) });
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//! ```
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//!
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//! Read the output line-by-line as it gets produced:
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//!
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//! ```no_run
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//! # futures_lite::future::block_on(async {
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//! use async_process::{Command, Stdio};
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//! use futures_lite::{io::BufReader, prelude::*};
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//!
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//! let mut child = Command::new("find")
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//! .arg(".")
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//! .stdout(Stdio::piped())
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//! .spawn()?;
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//!
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//! let mut lines = BufReader::new(child.stdout.take().unwrap()).lines();
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//!
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//! while let Some(line) = lines.next().await {
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//! println!("{}", line?);
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//! }
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//! # std::io::Result::Ok(()) });
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//! ```
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#![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
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#![doc(
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html_favicon_url = "https://raw.githubusercontent.com/smol-rs/smol/master/assets/images/logo_fullsize_transparent.png"
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)]
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#![doc(
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html_logo_url = "https://raw.githubusercontent.com/smol-rs/smol/master/assets/images/logo_fullsize_transparent.png"
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)]
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use std::convert::Infallible;
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use std::ffi::OsStr;
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use std::fmt;
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use std::path::Path;
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use std::pin::Pin;
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use std::sync::atomic::{AtomicUsize, Ordering};
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use std::sync::{Arc, Mutex};
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use std::task::{Context, Poll};
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use std::thread;
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#[cfg(unix)]
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use async_io::Async;
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#[cfg(unix)]
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use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, OwnedFd, RawFd};
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#[cfg(windows)]
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use blocking::Unblock;
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use async_lock::OnceCell;
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use futures_lite::{future, io, prelude::*};
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#[doc(no_inline)]
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pub use std::process::{ExitStatus, Output, Stdio};
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#[cfg(unix)]
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pub mod unix;
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#[cfg(windows)]
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pub mod windows;
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mod reaper;
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mod sealed {
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pub trait Sealed {}
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}
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#[cfg(test)]
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static DRIVER_THREAD_SPAWNED: std::sync::atomic::AtomicBool =
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std::sync::atomic::AtomicBool::new(false);
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/// The zombie process reaper.
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///
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/// This structure reaps zombie processes and emits the `SIGCHLD` signal.
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struct Reaper {
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/// Underlying system reaper.
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sys: reaper::Reaper,
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/// The number of tasks polling the SIGCHLD event.
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///
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/// If this is zero, the `async-process` thread must be spawned.
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drivers: AtomicUsize,
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/// Number of live `Child` instances currently running.
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///
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/// This is used to prevent the reaper thread from being spawned right as the program closes,
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/// when the reaper thread isn't needed. This represents the number of active processes.
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child_count: AtomicUsize,
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}
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impl Reaper {
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/// Get the singleton instance of the reaper.
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fn get() -> &'static Self {
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static REAPER: OnceCell<Reaper> = OnceCell::new();
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REAPER.get_or_init_blocking(|| Reaper {
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sys: reaper::Reaper::new(),
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drivers: AtomicUsize::new(0),
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child_count: AtomicUsize::new(0),
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})
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}
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/// Ensure that the reaper is driven.
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///
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/// If there are no active `driver()` callers, this will spawn the `async-process` thread.
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#[inline]
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fn ensure_driven(&'static self) {
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if self
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.drivers
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.compare_exchange(0, 1, Ordering::SeqCst, Ordering::Acquire)
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.is_ok()
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{
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self.start_driver_thread();
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}
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}
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/// Start the `async-process` thread.
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#[cold]
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fn start_driver_thread(&'static self) {
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#[cfg(test)]
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DRIVER_THREAD_SPAWNED
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.compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
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.unwrap_or_else(|_| unreachable!("Driver thread already spawned"));
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thread::Builder::new()
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.name("async-process".to_string())
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.spawn(move || {
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let driver = async move {
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// No need to bump self.drivers, it was already bumped in ensure_driven.
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let guard = self.sys.lock().await;
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self.sys.reap(guard).await
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};
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#[cfg(unix)]
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async_io::block_on(driver);
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#[cfg(not(unix))]
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future::block_on(driver);
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})
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.expect("cannot spawn async-process thread");
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}
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/// Register a process with this reaper.
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fn register(&'static self, child: std::process::Child) -> io::Result<reaper::ChildGuard> {
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self.ensure_driven();
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self.sys.register(child)
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}
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}
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cfg_if::cfg_if! {
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if #[cfg(windows)] {
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// Wraps a sync I/O type into an async I/O type.
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fn wrap<T>(io: T) -> io::Result<Unblock<T>> {
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Ok(Unblock::new(io))
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}
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} else if #[cfg(unix)] {
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/// Wrap a file descriptor into a non-blocking I/O type.
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fn wrap<T: std::os::unix::io::AsFd>(io: T) -> io::Result<Async<T>> {
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Async::new(io)
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}
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}
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}
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/// A guard that can kill child processes, or push them into the zombie list.
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struct ChildGuard {
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inner: reaper::ChildGuard,
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reap_on_drop: bool,
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kill_on_drop: bool,
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reaper: &'static Reaper,
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}
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impl ChildGuard {
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fn get_mut(&mut self) -> &mut std::process::Child {
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self.inner.get_mut()
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}
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}
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// When the last reference to the child process is dropped, push it into the zombie list.
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impl Drop for ChildGuard {
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fn drop(&mut self) {
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if self.kill_on_drop {
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self.get_mut().kill().ok();
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}
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if self.reap_on_drop {
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self.inner.reap(&self.reaper.sys);
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}
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// Decrement number of children.
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self.reaper.child_count.fetch_sub(1, Ordering::Acquire);
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}
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}
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/// A spawned child process.
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///
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/// The process can be in running or exited state. Use [`status()`][`Child::status()`] or
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/// [`output()`][`Child::output()`] to wait for it to exit.
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///
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/// If the [`Child`] is dropped, the process keeps running in the background.
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///
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/// # Examples
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///
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/// Spawn a process and wait for it to complete:
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///
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/// ```no_run
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/// # futures_lite::future::block_on(async {
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/// use async_process::Command;
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///
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/// Command::new("cp").arg("a.txt").arg("b.txt").status().await?;
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/// # std::io::Result::Ok(()) });
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/// ```
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pub struct Child {
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/// The handle for writing to the child's standard input (stdin), if it has been captured.
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pub stdin: Option<ChildStdin>,
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/// The handle for reading from the child's standard output (stdout), if it has been captured.
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pub stdout: Option<ChildStdout>,
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/// The handle for reading from the child's standard error (stderr), if it has been captured.
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pub stderr: Option<ChildStderr>,
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/// The inner child process handle.
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child: Arc<Mutex<ChildGuard>>,
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}
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impl Child {
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/// Wraps the inner child process handle and registers it in the global process list.
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///
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/// The "async-process" thread waits for processes in the global list and cleans up the
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/// resources when they exit.
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fn new(cmd: &mut Command) -> io::Result<Child> {
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// Make sure the reaper exists before we spawn the child process.
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let reaper = Reaper::get();
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let mut child = cmd.inner.spawn()?;
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// Convert sync I/O types into async I/O types.
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let stdin = child.stdin.take().map(wrap).transpose()?.map(ChildStdin);
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let stdout = child.stdout.take().map(wrap).transpose()?.map(ChildStdout);
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let stderr = child.stderr.take().map(wrap).transpose()?.map(ChildStderr);
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// Bump the child count.
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reaper.child_count.fetch_add(1, Ordering::Relaxed);
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// Register the child process in the global list.
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let inner = reaper.register(child)?;
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Ok(Child {
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stdin,
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stdout,
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stderr,
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child: Arc::new(Mutex::new(ChildGuard {
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inner,
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reap_on_drop: cmd.reap_on_drop,
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kill_on_drop: cmd.kill_on_drop,
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reaper,
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})),
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})
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}
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/// Returns the OS-assigned process identifier associated with this child.
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///
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/// # Examples
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///
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/// ```no_run
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/// # futures_lite::future::block_on(async {
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/// use async_process::Command;
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///
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/// let mut child = Command::new("ls").spawn()?;
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/// println!("id: {}", child.id());
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/// # std::io::Result::Ok(()) });
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/// ```
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pub fn id(&self) -> u32 {
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self.child.lock().unwrap().get_mut().id()
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}
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/// Forces the child process to exit.
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///
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/// If the child has already exited, an [`InvalidInput`] error is returned.
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///
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/// This is equivalent to sending a SIGKILL on Unix platforms.
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///
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/// [`InvalidInput`]: `std::io::ErrorKind::InvalidInput`
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///
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/// # Examples
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///
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/// ```no_run
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/// # futures_lite::future::block_on(async {
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/// use async_process::Command;
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///
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/// let mut child = Command::new("yes").spawn()?;
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/// child.kill()?;
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/// println!("exit status: {}", child.status().await?);
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/// # std::io::Result::Ok(()) });
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/// ```
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pub fn kill(&mut self) -> io::Result<()> {
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self.child.lock().unwrap().get_mut().kill()
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}
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/// Returns the exit status if the process has exited.
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///
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/// Unlike [`status()`][`Child::status()`], this method will not drop the stdin handle.
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///
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/// # Examples
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///
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/// ```no_run
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/// # futures_lite::future::block_on(async {
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/// use async_process::Command;
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///
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/// let mut child = Command::new("ls").spawn()?;
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///
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/// match child.try_status()? {
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/// None => println!("still running"),
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/// Some(status) => println!("exited with: {}", status),
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/// }
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/// # std::io::Result::Ok(()) });
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/// ```
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pub fn try_status(&self) -> io::Result<Option<ExitStatus>> {
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self.child.lock().unwrap().get_mut().try_wait()
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}
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/// Drops the stdin handle and waits for the process to exit.
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///
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/// Closing the stdin of the process helps avoid deadlocks. It ensures that the process does
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/// not block waiting for input from the parent process while the parent waits for the child to
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/// exit.
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///
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/// # Examples
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///
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/// ```no_run
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/// # futures_lite::future::block_on(async {
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/// use async_process::{Command, Stdio};
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///
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/// let mut child = Command::new("cp")
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/// .arg("a.txt")
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/// .arg("b.txt")
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/// .spawn()?;
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///
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/// println!("exit status: {}", child.status().await?);
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/// # std::io::Result::Ok(()) });
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/// ```
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pub fn status(&mut self) -> impl Future<Output = io::Result<ExitStatus>> {
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self.stdin.take();
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self.status_no_drop()
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}
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/// Waits for the process to exit.
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///
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/// Unlike `status`, does not drop the stdin handle. You are responsible
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/// for avoiding deadlocks caused by the child blocking on stdin while the
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/// parent blocks on waiting for the process to exit.
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///
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/// # Examples
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///
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/// ```no_run
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/// # futures_lite::future::block_on(async {
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/// use async_process::{Command, Stdio};
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///
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/// let child = Command::new("cp")
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/// .arg("a.txt")
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/// .arg("b.txt")
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/// .spawn()?;
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///
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/// println!("exit status: {}", child.status_no_drop().await?);
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/// # std::io::Result::Ok(()) });
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/// ```
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pub fn status_no_drop(&self) -> impl Future<Output = io::Result<ExitStatus>> {
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let child = self.child.clone();
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async move { Reaper::get().sys.status(&child).await }
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}
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/// Drops the stdin handle and collects the output of the process.
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///
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/// Closing the stdin of the process helps avoid deadlocks. It ensures that the process does
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/// not block waiting for input from the parent process while the parent waits for the child to
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/// exit.
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///
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/// In order to capture the output of the process, [`Command::stdout()`] and
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/// [`Command::stderr()`] must be configured with [`Stdio::piped()`].
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///
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/// # Examples
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///
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/// ```no_run
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/// # futures_lite::future::block_on(async {
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/// use async_process::{Command, Stdio};
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///
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/// let child = Command::new("ls")
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/// .stdout(Stdio::piped())
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/// .stderr(Stdio::piped())
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/// .spawn()?;
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///
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/// let out = child.output().await?;
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/// # std::io::Result::Ok(()) });
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/// ```
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pub fn output(mut self) -> impl Future<Output = io::Result<Output>> {
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// A future that waits for the exit status.
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let status = self.status();
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// A future that collects stdout.
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let stdout = self.stdout.take();
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let stdout = async move {
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let mut v = Vec::new();
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if let Some(mut s) = stdout {
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s.read_to_end(&mut v).await?;
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}
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io::Result::Ok(v)
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};
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// A future that collects stderr.
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let stderr = self.stderr.take();
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let stderr = async move {
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let mut v = Vec::new();
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if let Some(mut s) = stderr {
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s.read_to_end(&mut v).await?;
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}
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io::Result::Ok(v)
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};
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async move {
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let (stdout, stderr) = future::try_zip(stdout, stderr).await?;
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let status = status.await?;
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Ok(Output {
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status,
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stdout,
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stderr,
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})
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}
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}
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}
|
|
|
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impl fmt::Debug for Child {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.debug_struct("Child")
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.field("stdin", &self.stdin)
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.field("stdout", &self.stdout)
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.field("stderr", &self.stderr)
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.finish()
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}
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}
|
|
|
|
/// A handle to a child process's standard input (stdin).
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///
|
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/// When a [`ChildStdin`] is dropped, the underlying handle gets clossed. If the child process was
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/// previously blocked on input, it becomes unblocked after dropping.
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|
#[derive(Debug)]
|
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pub struct ChildStdin(
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#[cfg(windows)] Unblock<std::process::ChildStdin>,
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#[cfg(unix)] Async<std::process::ChildStdin>,
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|
);
|
|
|
|
impl ChildStdin {
|
|
/// Convert async_process::ChildStdin into std::process::Stdio.
|
|
///
|
|
/// You can use it to associate to the next process.
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|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// # futures_lite::future::block_on(async {
|
|
/// use async_process::Command;
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|
/// use std::process::Stdio;
|
|
///
|
|
/// let mut ls_child = Command::new("ls").stdin(Stdio::piped()).spawn()?;
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/// let stdio:Stdio = ls_child.stdin.take().unwrap().into_stdio().await?;
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///
|
|
/// let mut echo_child = Command::new("echo").arg("./").stdout(stdio).spawn()?;
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///
|
|
/// # std::io::Result::Ok(()) });
|
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/// ```
|
|
pub async fn into_stdio(self) -> io::Result<std::process::Stdio> {
|
|
cfg_if::cfg_if! {
|
|
if #[cfg(windows)] {
|
|
Ok(self.0.into_inner().await.into())
|
|
} else if #[cfg(unix)] {
|
|
let child_stdin = self.0.into_inner()?;
|
|
blocking_fd(rustix::fd::AsFd::as_fd(&child_stdin))?;
|
|
Ok(child_stdin.into())
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl io::AsyncWrite for ChildStdin {
|
|
fn poll_write(
|
|
mut self: Pin<&mut Self>,
|
|
cx: &mut Context<'_>,
|
|
buf: &[u8],
|
|
) -> Poll<io::Result<usize>> {
|
|
Pin::new(&mut self.0).poll_write(cx, buf)
|
|
}
|
|
|
|
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
|
|
Pin::new(&mut self.0).poll_flush(cx)
|
|
}
|
|
|
|
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
|
|
Pin::new(&mut self.0).poll_close(cx)
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl AsRawFd for ChildStdin {
|
|
fn as_raw_fd(&self) -> RawFd {
|
|
self.0.as_raw_fd()
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl AsFd for ChildStdin {
|
|
fn as_fd(&self) -> BorrowedFd<'_> {
|
|
self.0.as_fd()
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl TryFrom<ChildStdin> for OwnedFd {
|
|
type Error = io::Error;
|
|
|
|
fn try_from(value: ChildStdin) -> Result<Self, Self::Error> {
|
|
value.0.try_into()
|
|
}
|
|
}
|
|
|
|
// TODO(notgull): Add mirroring AsRawHandle impls for all of the child handles
|
|
//
|
|
// at the moment this is pretty hard to do because of how they're wrapped in
|
|
// Unblock, meaning that we can't always access the underlying handle. async-fs
|
|
// gets around this by putting the handle in an Arc, but there's still some decision
|
|
// to be made about how to handle this (no pun intended)
|
|
|
|
/// A handle to a child process's standard output (stdout).
|
|
///
|
|
/// When a [`ChildStdout`] is dropped, the underlying handle gets closed.
|
|
#[derive(Debug)]
|
|
pub struct ChildStdout(
|
|
#[cfg(windows)] Unblock<std::process::ChildStdout>,
|
|
#[cfg(unix)] Async<std::process::ChildStdout>,
|
|
);
|
|
|
|
impl ChildStdout {
|
|
/// Convert async_process::ChildStdout into std::process::Stdio.
|
|
///
|
|
/// You can use it to associate to the next process.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// # futures_lite::future::block_on(async {
|
|
/// use async_process::Command;
|
|
/// use std::process::Stdio;
|
|
/// use std::io::Read;
|
|
/// use futures_lite::AsyncReadExt;
|
|
///
|
|
/// let mut ls_child = Command::new("ls").stdout(Stdio::piped()).spawn()?;
|
|
/// let stdio:Stdio = ls_child.stdout.take().unwrap().into_stdio().await?;
|
|
///
|
|
/// let mut echo_child = Command::new("echo").stdin(stdio).stdout(Stdio::piped()).spawn()?;
|
|
/// let mut buf = vec![];
|
|
/// echo_child.stdout.take().unwrap().read(&mut buf).await;
|
|
/// # std::io::Result::Ok(()) });
|
|
/// ```
|
|
pub async fn into_stdio(self) -> io::Result<std::process::Stdio> {
|
|
cfg_if::cfg_if! {
|
|
if #[cfg(windows)] {
|
|
Ok(self.0.into_inner().await.into())
|
|
} else if #[cfg(unix)] {
|
|
let child_stdout = self.0.into_inner()?;
|
|
blocking_fd(rustix::fd::AsFd::as_fd(&child_stdout))?;
|
|
Ok(child_stdout.into())
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl io::AsyncRead for ChildStdout {
|
|
fn poll_read(
|
|
mut self: Pin<&mut Self>,
|
|
cx: &mut Context<'_>,
|
|
buf: &mut [u8],
|
|
) -> Poll<io::Result<usize>> {
|
|
Pin::new(&mut self.0).poll_read(cx, buf)
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl AsRawFd for ChildStdout {
|
|
fn as_raw_fd(&self) -> RawFd {
|
|
self.0.as_raw_fd()
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl AsFd for ChildStdout {
|
|
fn as_fd(&self) -> BorrowedFd<'_> {
|
|
self.0.as_fd()
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl TryFrom<ChildStdout> for OwnedFd {
|
|
type Error = io::Error;
|
|
|
|
fn try_from(value: ChildStdout) -> Result<Self, Self::Error> {
|
|
value.0.try_into()
|
|
}
|
|
}
|
|
|
|
/// A handle to a child process's standard error (stderr).
|
|
///
|
|
/// When a [`ChildStderr`] is dropped, the underlying handle gets closed.
|
|
#[derive(Debug)]
|
|
pub struct ChildStderr(
|
|
#[cfg(windows)] Unblock<std::process::ChildStderr>,
|
|
#[cfg(unix)] Async<std::process::ChildStderr>,
|
|
);
|
|
|
|
impl ChildStderr {
|
|
/// Convert async_process::ChildStderr into std::process::Stdio.
|
|
///
|
|
/// You can use it to associate to the next process.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// # futures_lite::future::block_on(async {
|
|
/// use async_process::Command;
|
|
/// use std::process::Stdio;
|
|
///
|
|
/// let mut ls_child = Command::new("ls").arg("x").stderr(Stdio::piped()).spawn()?;
|
|
/// let stdio:Stdio = ls_child.stderr.take().unwrap().into_stdio().await?;
|
|
///
|
|
/// let mut echo_child = Command::new("echo").stdin(stdio).spawn()?;
|
|
/// # std::io::Result::Ok(()) });
|
|
/// ```
|
|
pub async fn into_stdio(self) -> io::Result<std::process::Stdio> {
|
|
cfg_if::cfg_if! {
|
|
if #[cfg(windows)] {
|
|
Ok(self.0.into_inner().await.into())
|
|
} else if #[cfg(unix)] {
|
|
let child_stderr = self.0.into_inner()?;
|
|
blocking_fd(rustix::fd::AsFd::as_fd(&child_stderr))?;
|
|
Ok(child_stderr.into())
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl io::AsyncRead for ChildStderr {
|
|
fn poll_read(
|
|
mut self: Pin<&mut Self>,
|
|
cx: &mut Context<'_>,
|
|
buf: &mut [u8],
|
|
) -> Poll<io::Result<usize>> {
|
|
Pin::new(&mut self.0).poll_read(cx, buf)
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl AsRawFd for ChildStderr {
|
|
fn as_raw_fd(&self) -> RawFd {
|
|
self.0.as_raw_fd()
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl AsFd for ChildStderr {
|
|
fn as_fd(&self) -> BorrowedFd<'_> {
|
|
self.0.as_fd()
|
|
}
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
impl TryFrom<ChildStderr> for OwnedFd {
|
|
type Error = io::Error;
|
|
|
|
fn try_from(value: ChildStderr) -> Result<Self, Self::Error> {
|
|
value.0.try_into()
|
|
}
|
|
}
|
|
|
|
/// Runs the driver for the asynchronous processes.
|
|
///
|
|
/// This future takes control of global structures related to driving [`Child`]ren and reaping
|
|
/// zombie processes. These responsibilities include listening for the `SIGCHLD` signal and
|
|
/// making sure zombie processes are successfully waited on.
|
|
///
|
|
/// If multiple tasks run `driver()` at once, only one will actually drive the reaper; the other
|
|
/// ones will just sleep. If a task that is driving the reaper is dropped, a previously sleeping
|
|
/// task will take over. If all tasks driving the reaper are dropped, the "async-process" thread
|
|
/// will be spawned. The "async-process" thread just blocks on this future and will automatically
|
|
/// be spawned if no tasks are driving the reaper once a [`Child`] is created.
|
|
///
|
|
/// This future will never complete. It is intended to be ran on a background task in your
|
|
/// executor of choice.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// use async_executor::Executor;
|
|
/// use async_process::{driver, Command};
|
|
///
|
|
/// # futures_lite::future::block_on(async {
|
|
/// // Create an executor and run on it.
|
|
/// let ex = Executor::new();
|
|
/// ex.run(async {
|
|
/// // Run the driver future in the background.
|
|
/// ex.spawn(driver()).detach();
|
|
///
|
|
/// // Run a command.
|
|
/// Command::new("ls").output().await.ok();
|
|
/// }).await;
|
|
/// # });
|
|
/// ```
|
|
#[allow(clippy::manual_async_fn)]
|
|
#[inline]
|
|
pub fn driver() -> impl Future<Output = Infallible> + Send + 'static {
|
|
async {
|
|
// Get the reaper.
|
|
let reaper = Reaper::get();
|
|
|
|
// Make sure the reaper knows we're driving it.
|
|
reaper.drivers.fetch_add(1, Ordering::SeqCst);
|
|
|
|
// Decrement the driver count when this future is dropped.
|
|
let _guard = CallOnDrop(|| {
|
|
let prev_count = reaper.drivers.fetch_sub(1, Ordering::SeqCst);
|
|
|
|
// If this was the last driver, and there are still resources actively using the
|
|
// reaper, make sure that there is a thread driving the reaper.
|
|
if prev_count == 1
|
|
&& (reaper.child_count.load(Ordering::SeqCst) > 0 || reaper.sys.has_zombies())
|
|
{
|
|
reaper.ensure_driven();
|
|
}
|
|
});
|
|
|
|
// Acquire the reaper lock and start polling the SIGCHLD event.
|
|
let guard = reaper.sys.lock().await;
|
|
reaper.sys.reap(guard).await
|
|
}
|
|
}
|
|
|
|
/// A builder for spawning processes.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// # futures_lite::future::block_on(async {
|
|
/// use async_process::Command;
|
|
///
|
|
/// let output = if cfg!(target_os = "windows") {
|
|
/// Command::new("cmd").args(&["/C", "echo hello"]).output().await?
|
|
/// } else {
|
|
/// Command::new("sh").arg("-c").arg("echo hello").output().await?
|
|
/// };
|
|
/// # std::io::Result::Ok(()) });
|
|
/// ```
|
|
pub struct Command {
|
|
inner: std::process::Command,
|
|
stdin: bool,
|
|
stdout: bool,
|
|
stderr: bool,
|
|
reap_on_drop: bool,
|
|
kill_on_drop: bool,
|
|
}
|
|
|
|
impl Command {
|
|
/// Constructs a new [`Command`] for launching `program`.
|
|
///
|
|
/// The initial configuration (the working directory and environment variables) is inherited
|
|
/// from the current process.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// ```
|
|
pub fn new<S: AsRef<OsStr>>(program: S) -> Command {
|
|
Self::from(std::process::Command::new(program))
|
|
}
|
|
|
|
/// Adds a single argument to pass to the program.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("echo");
|
|
/// cmd.arg("hello");
|
|
/// cmd.arg("world");
|
|
/// ```
|
|
pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Command {
|
|
self.inner.arg(arg);
|
|
self
|
|
}
|
|
|
|
/// Adds multiple arguments to pass to the program.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("echo");
|
|
/// cmd.args(&["hello", "world"]);
|
|
/// ```
|
|
pub fn args<I, S>(&mut self, args: I) -> &mut Command
|
|
where
|
|
I: IntoIterator<Item = S>,
|
|
S: AsRef<OsStr>,
|
|
{
|
|
self.inner.args(args);
|
|
self
|
|
}
|
|
|
|
/// Configures an environment variable for the new process.
|
|
///
|
|
/// Note that environment variable names are case-insensitive (but case-preserving) on Windows,
|
|
/// and case-sensitive on all other platforms.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// cmd.env("PATH", "/bin");
|
|
/// ```
|
|
pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command
|
|
where
|
|
K: AsRef<OsStr>,
|
|
V: AsRef<OsStr>,
|
|
{
|
|
self.inner.env(key, val);
|
|
self
|
|
}
|
|
|
|
/// Configures multiple environment variables for the new process.
|
|
///
|
|
/// Note that environment variable names are case-insensitive (but case-preserving) on Windows,
|
|
/// and case-sensitive on all other platforms.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// cmd.envs(vec![("PATH", "/bin"), ("TERM", "xterm-256color")]);
|
|
/// ```
|
|
pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Command
|
|
where
|
|
I: IntoIterator<Item = (K, V)>,
|
|
K: AsRef<OsStr>,
|
|
V: AsRef<OsStr>,
|
|
{
|
|
self.inner.envs(vars);
|
|
self
|
|
}
|
|
|
|
/// Removes an environment variable mapping.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// cmd.env_remove("PATH");
|
|
/// ```
|
|
pub fn env_remove<K: AsRef<OsStr>>(&mut self, key: K) -> &mut Command {
|
|
self.inner.env_remove(key);
|
|
self
|
|
}
|
|
|
|
/// Removes all environment variable mappings.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// cmd.env_clear();
|
|
/// ```
|
|
pub fn env_clear(&mut self) -> &mut Command {
|
|
self.inner.env_clear();
|
|
self
|
|
}
|
|
|
|
/// Configures the working directory for the new process.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::Command;
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// cmd.current_dir("/");
|
|
/// ```
|
|
pub fn current_dir<P: AsRef<Path>>(&mut self, dir: P) -> &mut Command {
|
|
self.inner.current_dir(dir);
|
|
self
|
|
}
|
|
|
|
/// Configures the standard input (stdin) for the new process.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::{Command, Stdio};
|
|
///
|
|
/// let mut cmd = Command::new("cat");
|
|
/// cmd.stdin(Stdio::null());
|
|
/// ```
|
|
pub fn stdin<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
|
|
self.stdin = true;
|
|
self.inner.stdin(cfg);
|
|
self
|
|
}
|
|
|
|
/// Configures the standard output (stdout) for the new process.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::{Command, Stdio};
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// cmd.stdout(Stdio::piped());
|
|
/// ```
|
|
pub fn stdout<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
|
|
self.stdout = true;
|
|
self.inner.stdout(cfg);
|
|
self
|
|
}
|
|
|
|
/// Configures the standard error (stderr) for the new process.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::{Command, Stdio};
|
|
///
|
|
/// let mut cmd = Command::new("ls");
|
|
/// cmd.stderr(Stdio::piped());
|
|
/// ```
|
|
pub fn stderr<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
|
|
self.stderr = true;
|
|
self.inner.stderr(cfg);
|
|
self
|
|
}
|
|
|
|
/// Configures whether to reap the zombie process when [`Child`] is dropped.
|
|
///
|
|
/// When the process finishes, it becomes a "zombie" and some resources associated with it
|
|
/// remain until [`Child::try_status()`], [`Child::status()`], or [`Child::output()`] collects
|
|
/// its exit code.
|
|
///
|
|
/// If its exit code is never collected, the resources may leak forever. This crate has a
|
|
/// background thread named "async-process" that collects such "zombie" processes and then
|
|
/// "reaps" them, thus preventing the resource leaks.
|
|
///
|
|
/// The default value of this option is `true`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::{Command, Stdio};
|
|
///
|
|
/// let mut cmd = Command::new("cat");
|
|
/// cmd.reap_on_drop(false);
|
|
/// ```
|
|
pub fn reap_on_drop(&mut self, reap_on_drop: bool) -> &mut Command {
|
|
self.reap_on_drop = reap_on_drop;
|
|
self
|
|
}
|
|
|
|
/// Configures whether to kill the process when [`Child`] is dropped.
|
|
///
|
|
/// The default value of this option is `false`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use async_process::{Command, Stdio};
|
|
///
|
|
/// let mut cmd = Command::new("cat");
|
|
/// cmd.kill_on_drop(true);
|
|
/// ```
|
|
pub fn kill_on_drop(&mut self, kill_on_drop: bool) -> &mut Command {
|
|
self.kill_on_drop = kill_on_drop;
|
|
self
|
|
}
|
|
|
|
/// Executes the command and returns the [`Child`] handle to it.
|
|
///
|
|
/// If not configured, stdin, stdout and stderr will be set to [`Stdio::inherit()`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// # futures_lite::future::block_on(async {
|
|
/// use async_process::Command;
|
|
///
|
|
/// let child = Command::new("ls").spawn()?;
|
|
/// # std::io::Result::Ok(()) });
|
|
/// ```
|
|
pub fn spawn(&mut self) -> io::Result<Child> {
|
|
if !self.stdin {
|
|
self.inner.stdin(Stdio::inherit());
|
|
}
|
|
if !self.stdout {
|
|
self.inner.stdout(Stdio::inherit());
|
|
}
|
|
if !self.stderr {
|
|
self.inner.stderr(Stdio::inherit());
|
|
}
|
|
|
|
Child::new(self)
|
|
}
|
|
|
|
/// Executes the command, waits for it to exit, and returns the exit status.
|
|
///
|
|
/// If not configured, stdin, stdout and stderr will be set to [`Stdio::inherit()`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// # futures_lite::future::block_on(async {
|
|
/// use async_process::Command;
|
|
///
|
|
/// let status = Command::new("cp")
|
|
/// .arg("a.txt")
|
|
/// .arg("b.txt")
|
|
/// .status()
|
|
/// .await?;
|
|
/// # std::io::Result::Ok(()) });
|
|
/// ```
|
|
pub fn status(&mut self) -> impl Future<Output = io::Result<ExitStatus>> {
|
|
let child = self.spawn();
|
|
async { child?.status().await }
|
|
}
|
|
|
|
/// Executes the command and collects its output.
|
|
///
|
|
/// If not configured, stdin will be set to [`Stdio::null()`], and stdout and stderr will be
|
|
/// set to [`Stdio::piped()`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```no_run
|
|
/// # futures_lite::future::block_on(async {
|
|
/// use async_process::Command;
|
|
///
|
|
/// let output = Command::new("cat")
|
|
/// .arg("a.txt")
|
|
/// .output()
|
|
/// .await?;
|
|
/// # std::io::Result::Ok(()) });
|
|
/// ```
|
|
pub fn output(&mut self) -> impl Future<Output = io::Result<Output>> {
|
|
if !self.stdin {
|
|
self.inner.stdin(Stdio::null());
|
|
}
|
|
if !self.stdout {
|
|
self.inner.stdout(Stdio::piped());
|
|
}
|
|
if !self.stderr {
|
|
self.inner.stderr(Stdio::piped());
|
|
}
|
|
|
|
let child = Child::new(self);
|
|
async { child?.output().await }
|
|
}
|
|
}
|
|
|
|
impl From<std::process::Command> for Command {
|
|
fn from(inner: std::process::Command) -> Self {
|
|
Self {
|
|
inner,
|
|
stdin: false,
|
|
stdout: false,
|
|
stderr: false,
|
|
reap_on_drop: true,
|
|
kill_on_drop: false,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl fmt::Debug for Command {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
if f.alternate() {
|
|
f.debug_struct("Command")
|
|
.field("inner", &self.inner)
|
|
.field("stdin", &self.stdin)
|
|
.field("stdout", &self.stdout)
|
|
.field("stderr", &self.stderr)
|
|
.field("reap_on_drop", &self.reap_on_drop)
|
|
.field("kill_on_drop", &self.kill_on_drop)
|
|
.finish()
|
|
} else {
|
|
// Stdlib outputs command-line in Debug for Command. This does the
|
|
// same, if not in "alternate" (long pretty-printed) mode.
|
|
// This is useful for logs, for example.
|
|
fmt::Debug::fmt(&self.inner, f)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Moves `Fd` out of non-blocking mode.
|
|
#[cfg(unix)]
|
|
fn blocking_fd(fd: rustix::fd::BorrowedFd<'_>) -> io::Result<()> {
|
|
cfg_if::cfg_if! {
|
|
// ioctl(FIONBIO) sets the flag atomically, but we use this only on Linux
|
|
// for now, as with the standard library, because it seems to behave
|
|
// differently depending on the platform.
|
|
// https://github.com/rust-lang/rust/commit/efeb42be2837842d1beb47b51bb693c7474aba3d
|
|
// https://github.com/libuv/libuv/blob/e9d91fccfc3e5ff772d5da90e1c4a24061198ca0/src/unix/poll.c#L78-L80
|
|
// https://github.com/tokio-rs/mio/commit/0db49f6d5caf54b12176821363d154384357e70a
|
|
if #[cfg(target_os = "linux")] {
|
|
rustix::io::ioctl_fionbio(fd, false)?;
|
|
} else {
|
|
let previous = rustix::fs::fcntl_getfl(fd)?;
|
|
let new = previous & !rustix::fs::OFlags::NONBLOCK;
|
|
if new != previous {
|
|
rustix::fs::fcntl_setfl(fd, new)?;
|
|
}
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
struct CallOnDrop<F: FnMut()>(F);
|
|
|
|
impl<F: FnMut()> Drop for CallOnDrop<F> {
|
|
fn drop(&mut self) {
|
|
(self.0)();
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
#[test]
|
|
fn polled_driver() {
|
|
use super::{driver, Command};
|
|
use futures_lite::future;
|
|
use futures_lite::prelude::*;
|
|
|
|
let is_thread_spawned =
|
|
|| super::DRIVER_THREAD_SPAWNED.load(std::sync::atomic::Ordering::SeqCst);
|
|
|
|
#[cfg(unix)]
|
|
fn command() -> Command {
|
|
let mut cmd = Command::new("sh");
|
|
cmd.arg("-c").arg("echo hello");
|
|
cmd
|
|
}
|
|
|
|
#[cfg(windows)]
|
|
fn command() -> Command {
|
|
let mut cmd = Command::new("cmd");
|
|
cmd.arg("/C").arg("echo hello");
|
|
cmd
|
|
}
|
|
|
|
#[cfg(unix)]
|
|
const OUTPUT: &[u8] = b"hello\n";
|
|
#[cfg(windows)]
|
|
const OUTPUT: &[u8] = b"hello\r\n";
|
|
|
|
future::block_on(async {
|
|
// Thread should not be spawned off the bat.
|
|
assert!(!is_thread_spawned());
|
|
|
|
// Spawn a driver.
|
|
let mut driver1 = Box::pin(driver());
|
|
future::poll_once(&mut driver1).await;
|
|
assert!(!is_thread_spawned());
|
|
|
|
// We should be able to run the driver in parallel with a process future.
|
|
async {
|
|
(&mut driver1).await;
|
|
}
|
|
.or(async {
|
|
let output = command().output().await.unwrap();
|
|
assert_eq!(output.stdout, OUTPUT);
|
|
})
|
|
.await;
|
|
assert!(!is_thread_spawned());
|
|
|
|
// Spawn a second driver.
|
|
let mut driver2 = Box::pin(driver());
|
|
future::poll_once(&mut driver2).await;
|
|
assert!(!is_thread_spawned());
|
|
|
|
// Poll both drivers in parallel.
|
|
async {
|
|
(&mut driver1).await;
|
|
}
|
|
.or(async {
|
|
(&mut driver2).await;
|
|
})
|
|
.or(async {
|
|
let output = command().output().await.unwrap();
|
|
assert_eq!(output.stdout, OUTPUT);
|
|
})
|
|
.await;
|
|
assert!(!is_thread_spawned());
|
|
|
|
// Once one is dropped, the other should take over.
|
|
drop(driver1);
|
|
assert!(!is_thread_spawned());
|
|
|
|
// Poll driver2 in parallel with a process future.
|
|
async {
|
|
(&mut driver2).await;
|
|
}
|
|
.or(async {
|
|
let output = command().output().await.unwrap();
|
|
assert_eq!(output.stdout, OUTPUT);
|
|
})
|
|
.await;
|
|
assert!(!is_thread_spawned());
|
|
|
|
// Once driver2 is dropped, the thread should not be spawned, as there are no active
|
|
// child processes..
|
|
drop(driver2);
|
|
assert!(!is_thread_spawned());
|
|
|
|
// We should now be able to poll the process future independently, it will spawn the
|
|
// thread.
|
|
let output = command().output().await.unwrap();
|
|
assert_eq!(output.stdout, OUTPUT);
|
|
assert!(is_thread_spawned());
|
|
});
|
|
}
|
|
}
|