1 files changed, 34 insertions, 0 deletions
diff --git a/third_party/rust/libloading/src/util.rs b/third_party/rust/libloading/src/util.rs
new file mode 100644
index 0000000000..599e6c254e
--- /dev/null
+++ b/third_party/rust/libloading/src/util.rs
@@ -0,0 +1,34 @@
+use std::borrow::Cow;
+use std::ffi::{CStr, CString};
+use std::os::raw;
+
+use crate::Error;
+
+/// Checks for the last byte and avoids allocating if it is zero.
+///
+/// Non-last null bytes still result in an error.
+pub(crate) fn cstr_cow_from_bytes(slice: &[u8]) -> Result<Cow<'_, CStr>, Error> {
+    static ZERO: raw::c_char = 0;
+    Ok(match slice.last() {
+        // Slice out of 0 elements
+        None => unsafe { Cow::Borrowed(CStr::from_ptr(&ZERO)) },
+        // Slice with trailing 0
+        Some(&0) => Cow::Borrowed(
+            CStr::from_bytes_with_nul(slice)
+                .map_err(|source| Error::CreateCStringWithTrailing { source })?,
+        ),
+        // Slice with no trailing 0
+        Some(_) => {
+            Cow::Owned(CString::new(slice).map_err(|source| Error::CreateCString { source })?)
+        }
+    })
+}
+
+#[inline]
+pub(crate) fn ensure_compatible_types<T, E>() -> Result<(), Error> {
+    if ::std::mem::size_of::<T>() != ::std::mem::size_of::<E>() {
+        Err(Error::IncompatibleSize)
+    } else {
+        Ok(())
+    }
+}