third_party_rust_os_str_bytes/tests/random_common.rs

#![allow(dead_code)]

use std::ffi::OsString;
#[cfg(unix)]
use std::os::unix::ffi::OsStringExt;
#[cfg(windows)]
use std::os::windows::ffi::OsStringExt;
#[cfg(windows)]
use std::slice;

use getrandom::getrandom;

pub(crate) const SMALL_LENGTH: usize = 16;

pub(crate) const ITERATIONS: usize = 1024;

pub(crate) fn random_os_string(
    buffer_length: usize,
) -> Result<OsString, getrandom::Error> {
    let mut buffer = vec![0; buffer_length];
    #[cfg(unix)]
    {
        getrandom(&mut buffer)?;
        Ok(OsStringExt::from_vec(buffer))
    }
    #[cfg(windows)]
    {
        fn as_mut_bytes(buffer: &mut [u16]) -> &mut [u8] {
            // SAFETY: [u16] can always be transmuted to two [u8] bytes.
            unsafe {
                slice::from_raw_parts_mut(
                    buffer.as_mut_ptr().cast(),
                    buffer.len() * 2,
                )
            }
        }

        getrandom(as_mut_bytes(&mut buffer))?;
        Ok(OsStringExt::from_wide(&buffer))
    }
}