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//! A crate to wait on a child process with a particular timeout. //! //! This crate is an implementation for Unix and Windows of the ability to wait //! on a child process with a timeout specified. On Windows the implementation //! is fairly trivial as it's just a call to `WaitForSingleObject` with a //! timeout argument, but on Unix the implementation is much more involved. The //! current implementation registeres a `SIGCHLD` handler and initializes some //! global state. If your application is otherwise handling `SIGCHLD` then bugs //! may arise. //! //! # Example //! //! ```no_run //! use std::process::Command; //! use wait_timeout::ChildExt; //! //! let mut child = Command::new("foo").spawn().unwrap(); //! //! let status_code = match child.wait_timeout_ms(1_000).unwrap() { //! Some(status) => status.code(), //! None => { //! // child hasn't exited yet //! child.kill().unwrap(); //! child.wait().unwrap().code() //! } //! }; //! ``` #![deny(missing_docs, warnings)] extern crate kernel32; extern crate libc; extern crate time; extern crate winapi; #[macro_use] extern crate cfg_if; use std::fmt; use std::io; use std::process::Child; use std::time::Duration; /// Exit status from a child process. /// /// This type mirrors that in `std::process` but currently must be distinct as /// the one in `std::process` cannot be created. #[derive(Eq, PartialEq, Copy, Clone, Debug)] pub struct ExitStatus(imp::ExitStatus); #[cfg(unix)] #[path = "unix.rs"] mod imp; #[cfg(windows)] #[path = "windows.rs"] mod imp; /// Extension methods for the standard `std::process::Child` type. pub trait ChildExt { /// Deprecated, use `wait_timeout` instead. #[doc(hidden)] fn wait_timeout_ms(&mut self, ms: u32) -> io::Result<Option<ExitStatus>> { self.wait_timeout(Duration::from_millis(ms as u64)) } /// Wait for this child to exit, timing out after `ms` milliseconds have /// elapsed. /// /// If `Ok(None)` is returned then the timeout period elapsed without the /// child exiting, and if `Ok(Some(..))` is returned then the child exited /// with the specified exit code. /// /// # Warning /// /// Currently this function must be called with great care. If the child /// has already been waited on (e.g. `wait` returned a success) then this /// function will either wait on another process or fail spuriously on some /// platforms. This function may only be reliably called if the process has /// not already been waited on. /// /// Additionally, once this method completes the original child cannot be /// waited on reliably. The `wait` method on the original child may return /// spurious errors or have odd behavior on some platforms. If this /// function returns `Ok(None)`, however, it is safe to wait on the child /// with the normal libstd `wait` method. fn wait_timeout(&mut self, dur: Duration) -> io::Result<Option<ExitStatus>>; } impl ChildExt for Child { fn wait_timeout(&mut self, dur: Duration) -> io::Result<Option<ExitStatus>> { imp::wait_timeout(self, dur).map(|m| m.map(ExitStatus)) } } impl ExitStatus { /// Returns whether this exit status represents a successful execution. /// /// This typically means that the child process successfully exited with a /// status code of 0. pub fn success(&self) -> bool { self.0.success() } /// Returns the code associated with the child's exit event. /// /// On Unix this can return `None` if the child instead exited because of a /// signal. On Windows, however, this will always return `Some`. pub fn code(&self) -> Option<i32> { self.0.code() } /// Returns the Unix signal which terminated this process. /// /// Note that on Windows this will always return `None` and on Unix this /// will return `None` if the process successfully exited otherwise. pub fn unix_signal(&self) -> Option<i32> { self.0.unix_signal() } } impl fmt::Display for ExitStatus { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { if let Some(c) = self.code() { write!(f, "exit code: {}", c) } else if let Some(s) = self.unix_signal() { write!(f, "signal: {}", s) } else { write!(f, "exit status: unknown") } } }