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//! The host operating system, as far as spawning and executable lookup differ.
use std::path::{Path, PathBuf};
/// The host operating system, as far as spawning and executable lookup differ.
///
/// Passed explicitly so the Windows rules run, and are tested, on every OS.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum HostOs {
/// Windows: any regular file is executable, and `.cmd` shims exist.
Windows,
/// Every other host: a file is executable by its execute bit.
Other,
}
impl HostOs {
/// The host this build runs on.
pub const CURRENT: Self = if cfg!(windows) {
Self::Windows
} else {
Self::Other
};
/// Whether `path` is a regular file this host may execute: on Windows any
/// file, elsewhere one with an execute bit.
#[must_use]
pub fn is_executable_file(self, path: &Path) -> bool {
match self {
Self::Windows => path.is_file(),
Self::Other => is_unix_executable(path),
}
}
/// The largest `NAME=value` entry with its terminator, in bytes, one
/// environment variable may take on this host: the documented Windows limit
/// (32767 characters), and on other hosts the 128 KiB Linux caps one string
/// at (`MAX_ARG_STRLEN`).
#[must_use]
pub const fn max_env_entry_bytes(self) -> usize {
match self {
Self::Windows => 32_767,
Self::Other => 128 * 1024,
}
}
/// `path` as spawned: on Windows a path without an extension gets `.exe`.
pub(crate) fn spawn_name(self, path: &Path) -> PathBuf {
if self == Self::Windows && path.extension().is_none() {
path.with_added_extension("exe")
} else {
path.to_path_buf()
}
}
}
#[cfg(unix)]
fn is_unix_executable(path: &Path) -> bool {
use std::os::unix::fs::PermissionsExt as _;
std::fs::metadata(path)
.is_ok_and(|meta| meta.is_file() && meta.permissions().mode() & 0o111 != 0)
}
#[cfg(not(unix))]
fn is_unix_executable(path: &Path) -> bool {
path.is_file()
}