libloading/
util.rs

1use std::borrow::Cow;
2use std::ffi::{CStr, CString};
3use std::os::raw;
4
5use crate::Error;
6
7/// Checks for the last byte and avoids allocating if it is zero.
8///
9/// Non-last null bytes still result in an error.
10pub(crate) fn cstr_cow_from_bytes(slice: &[u8]) -> Result<Cow<'_, CStr>, Error> {
11    static ZERO: raw::c_char = 0;
12    Ok(match slice.last() {
13        // Slice out of 0 elements
14        None => unsafe { Cow::Borrowed(CStr::from_ptr(&ZERO)) },
15        // Slice with trailing 0
16        Some(&0) => Cow::Borrowed(
17            CStr::from_bytes_with_nul(slice)
18                .map_err(|source| Error::CreateCStringWithTrailing { source })?,
19        ),
20        // Slice with no trailing 0
21        Some(_) => {
22            Cow::Owned(CString::new(slice).map_err(|source| Error::CreateCString { source })?)
23        }
24    })
25}
26
27#[inline]
28pub(crate) fn ensure_compatible_types<T, E>() -> Result<(), Error> {
29    if ::std::mem::size_of::<T>() != ::std::mem::size_of::<E>() {
30        Err(Error::IncompatibleSize)
31    } else {
32        Ok(())
33    }
34}