feat: implement From<&CStr> for NvimStr (#239)

crates/types/src/str.rs

@@ -1,11 +1,16 @@
+use core::ffi::{self, CStr};
 use core::marker::PhantomData;
 use core::str::Utf8Error;
-use core::{cmp, ffi, fmt, hash, slice};
+use core::{cmp, fmt, hash, slice};
 use std::borrow::Cow;
 
 use crate::String as NvimString;
 
-/// TODO: docs.
+/// A borrowed version of [`NvimString`].
+///
+/// Values of this type can be created by calling
+/// [`as_nvim_str`](NvimString::as_nvim_str) on a [`NvimString`] or by
+/// converting a [`CStr`].
 #[derive(Copy, Clone)]
 #[repr(C)]
 pub struct NvimStr<'a> {
@@ -146,6 +151,13 @@ impl PartialEq for NvimStr<'_> {
     }
 }
 
+impl PartialEq<&str> for NvimStr<'_> {
+    #[inline]
+    fn eq(&self, other: &&str) -> bool {
+        self.as_bytes() == other.as_bytes()
+    }
+}
+
 impl Eq for NvimStr<'_> {}
 
 impl PartialOrd for NvimStr<'_> {
@@ -168,3 +180,33 @@ impl<'a> From<&'a NvimString> for NvimStr<'a> {
         string.as_nvim_str()
     }
 }
+
+impl<'a> From<&'a CStr> for NvimStr<'a> {
+    #[inline]
+    fn from(cstr: &'a CStr) -> Self {
+        Self {
+            data: cstr.as_ptr(),
+            len: cstr.to_bytes().len(),
+            _lifetime: PhantomData,
+        }
+    }
+}
+
+impl PartialEq<NvimStr<'_>> for &str {
+    #[inline]
+    fn eq(&self, other: &NvimStr<'_>) -> bool {
+        self.as_bytes() == other.as_bytes()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn from_cstr() {
+        let c_str = c"Hello, World!";
+        let nvim_str = NvimStr::from(c_str);
+        assert_eq!(nvim_str, "Hello, World!");
+    }
+}