Jakub KonkaandCole Miller
16dfc60ad2
Here's some backstory: * on macOS, @cole-miller and I noticed that since roughly Oct 2025, due to some changes to latest macOS Tahoe, for any spawned child process we needed to reset Mach exception ports (https://github.com/zed-industries/zed/issues/36754 + https://github.com/RemiKalbe/zed/commit/6e8f2d2ebe5a93753625a3026aeb996de8cb436b) * the changes in that PR achieve that via `pre_exec` hook on `std::process::Command` which then abandons `posix_spawn` syscall for `fork` + `execve` dance on macOS (we tracked it down in Rust's std implementation) * as it turns out, `fork` + `execve` is pretty expensive on macOS (apparently way more so than on other OSes like Linux) and `fork` takes a process-wide lock on the allocator which is bad * however, since we wanna reset exception ports on the child, the only official way supported by Rust's std is to use `pre_exec` hook * posix_spawn on macOS exposes this tho via a macOS specific extension to that syscall `posix_spawnattr_setexceptionports_np` but there is no way to use that via any standard interfaces in `std::process::Command` * thus, it seemed like a good idea to instead create our own custom Command wrapper that on non-macOS hosts is a zero-cost wrapper of `smol::process::Command`, while on macOS we reimplement the minimum to achieve `smol::process::Command` with `posix_spawn` under-the-hood Notably, this changeset improves git-blame in very large repos significantly. Release Notes: - Fixed performance spawning child processes on macOS by always forcing `posix_spawn` no matter what. --------- Co-authored-by: Cole Miller <cole@zed.dev>
133 lines
3.2 KiB
Rust
133 lines
3.2 KiB
Rust
use std::ffi::OsStr;
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#[cfg(not(target_os = "macos"))]
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use std::path::Path;
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#[cfg(target_os = "macos")]
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mod darwin;
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#[cfg(target_os = "macos")]
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pub use darwin::{Child, Command, Stdio};
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#[cfg(target_os = "windows")]
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const CREATE_NO_WINDOW: u32 = 0x0800_0000_u32;
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pub fn new_command(program: impl AsRef<OsStr>) -> Command {
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Command::new(program)
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}
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#[cfg(target_os = "windows")]
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pub fn new_std_command(program: impl AsRef<OsStr>) -> std::process::Command {
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use std::os::windows::process::CommandExt;
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let mut command = std::process::Command::new(program);
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command.creation_flags(CREATE_NO_WINDOW);
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command
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}
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#[cfg(not(target_os = "windows"))]
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pub fn new_std_command(program: impl AsRef<OsStr>) -> std::process::Command {
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std::process::Command::new(program)
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}
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#[cfg(not(target_os = "macos"))]
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pub type Child = smol::process::Child;
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#[cfg(not(target_os = "macos"))]
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pub use std::process::Stdio;
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#[cfg(not(target_os = "macos"))]
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#[derive(Debug)]
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pub struct Command(smol::process::Command);
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#[cfg(not(target_os = "macos"))]
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impl Command {
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#[inline]
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pub fn new(program: impl AsRef<OsStr>) -> Self {
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#[cfg(target_os = "windows")]
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{
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use smol::process::windows::CommandExt;
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let mut cmd = smol::process::Command::new(program);
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cmd.creation_flags(CREATE_NO_WINDOW);
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Self(cmd)
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}
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#[cfg(not(target_os = "windows"))]
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Self(smol::process::Command::new(program))
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}
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pub fn arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
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self.0.arg(arg);
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self
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}
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pub fn args<I, S>(&mut self, args: I) -> &mut Self
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where
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I: IntoIterator<Item = S>,
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S: AsRef<OsStr>,
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{
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self.0.args(args);
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self
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}
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pub fn env(&mut self, key: impl AsRef<OsStr>, val: impl AsRef<OsStr>) -> &mut Self {
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self.0.env(key, val);
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self
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}
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pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Self
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where
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I: IntoIterator<Item = (K, V)>,
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K: AsRef<OsStr>,
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V: AsRef<OsStr>,
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{
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self.0.envs(vars);
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self
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}
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pub fn env_remove(&mut self, key: impl AsRef<OsStr>) -> &mut Self {
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self.0.env_remove(key);
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self
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}
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pub fn env_clear(&mut self) -> &mut Self {
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self.0.env_clear();
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self
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}
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pub fn current_dir(&mut self, dir: impl AsRef<Path>) -> &mut Self {
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self.0.current_dir(dir);
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self
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}
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pub fn stdin(&mut self, cfg: impl Into<Stdio>) -> &mut Self {
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self.0.stdin(cfg.into());
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self
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}
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pub fn stdout(&mut self, cfg: impl Into<Stdio>) -> &mut Self {
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self.0.stdout(cfg.into());
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self
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}
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pub fn stderr(&mut self, cfg: impl Into<Stdio>) -> &mut Self {
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self.0.stderr(cfg.into());
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self
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}
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pub fn kill_on_drop(&mut self, kill_on_drop: bool) -> &mut Self {
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self.0.kill_on_drop(kill_on_drop);
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self
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}
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pub fn spawn(&mut self) -> std::io::Result<Child> {
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self.0.spawn()
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}
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pub async fn output(&mut self) -> std::io::Result<std::process::Output> {
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self.0.output().await
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}
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pub async fn status(&mut self) -> std::io::Result<std::process::ExitStatus> {
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self.0.status().await
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}
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}
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