From e819844b2ea35e5f6e1da0f96a9ae0c97e8bb602 Mon Sep 17 00:00:00 2001 From: Chris Denton Date: Wed, 18 May 2022 19:52:10 +0100 Subject: [PATCH] Windows: `CommandExt::async_pipes` --- std/src/os/windows/process.rs | 40 +++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/std/src/os/windows/process.rs b/std/src/os/windows/process.rs index 1c7e361c2..cf693618a 100644 --- a/std/src/os/windows/process.rs +++ b/std/src/os/windows/process.rs @@ -161,6 +161,37 @@ pub trait CommandExt: Sealed { /// `CommandLineToArgvW` escaping rules. #[stable(feature = "windows_process_extensions_raw_arg", since = "1.62.0")] fn raw_arg>(&mut self, text_to_append_as_is: S) -> &mut process::Command; + + /// When [`process::Command`] creates pipes, request that our side is always async. + /// + /// By default [`process::Command`] may choose to use pipes where both ends + /// are opened for synchronous read or write operations. By using + /// `async_pipes(true)`, this behavior is overridden so that our side is + /// always async. + /// + /// This is important because if doing async I/O a pipe or a file has to be + /// opened for async access. + /// + /// The end of the pipe sent to the child process will always be synchronous + /// regardless of this option. + /// + /// # Example + /// + /// ``` + /// #![feature(windows_process_extensions_async_pipes)] + /// use std::os::windows::process::CommandExt; + /// use std::process::{Command, Stdio}; + /// + /// # let program = ""; + /// + /// Command::new(program) + /// .async_pipes(true) + /// .stdin(Stdio::piped()) + /// .stdout(Stdio::piped()) + /// .stderr(Stdio::piped()); + /// ``` + #[unstable(feature = "windows_process_extensions_async_pipes", issue = "98289")] + fn async_pipes(&mut self, always_async: bool) -> &mut process::Command; } #[stable(feature = "windows_process_extensions", since = "1.16.0")] @@ -179,6 +210,15 @@ impl CommandExt for process::Command { self.as_inner_mut().raw_arg(raw_text.as_ref()); self } + + fn async_pipes(&mut self, always_async: bool) -> &mut process::Command { + // FIXME: This currently has an intentional no-op implementation. + // For the time being our side of the pipes will always be async. + // Once the ecosystem has adjusted, we may then be able to start making + // use of synchronous pipes within the standard library. + let _ = always_async; + self + } } #[unstable(feature = "windows_process_extensions_main_thread_handle", issue = "96723")]