bonsix/src/libstrerror.rs

/*
 * Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
 * SPDX-License-Identifier: FSFAP
 *
 * Copying and distribution of this file, with or without modification, are
 * permitted in any medium without royalty provided the copyright notice and
 * this notice are preserved.  This file is offered as-is, without any warranty.
 */

use std::ffi::{ c_int, c_char, CStr };

pub trait StrError { fn strerror(&self) -> String; }

impl StrError for std::io::Error {
	/* wrapper function for use in Rust */
	fn strerror(&self) -> String {
		/* Get the raw OS error. If it’s None, what the hell is going on‽ */
		let errno = self.raw_os_error().unwrap_or(0) as c_int;

		/* Get a CStr from the error message so that it’s referenced and then
		 * convert it to an owned value. If the string is not valid UTF-8,
		 * return that error instead. */
		match unsafe { CStr::from_ptr(strerror(errno)) }.to_str() {
			Ok(s) => s.to_owned(), // yay!! :D
			Err(e) => e.to_string(), // awww :(
		}
	}
}

/* binding to strerror(3p) */
extern "C" { fn strerror(errnum: c_int) -> *mut c_char; }