feat: some useful trait impls and conversions for NgxStr

Author: bavshin-f5

nginx-sys/src/string.rs

@@ -92,6 +92,18 @@ impl ngx_str_t {
     }
 }
 
+impl AsRef<[u8]> for ngx_str_t {
+    fn as_ref(&self) -> &[u8] {
+        self.as_bytes()
+    }
+}
+
+impl AsMut<[u8]> for ngx_str_t {
+    fn as_mut(&mut self) -> &mut [u8] {
+        self.as_bytes_mut()
+    }
+}
+
 impl Default for ngx_str_t {
     fn default() -> Self {
         Self::empty()
@@ -114,6 +126,26 @@ impl fmt::Display for ngx_str_t {
     }
 }
 
+impl PartialEq for ngx_str_t {
+    fn eq(&self, other: &Self) -> bool {
+        PartialEq::eq(self.as_bytes(), other.as_bytes())
+    }
+}
+
+impl Eq for ngx_str_t {}
+
+impl PartialOrd<Self> for ngx_str_t {
+    fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for ngx_str_t {
+    fn cmp(&self, other: &Self) -> core::cmp::Ordering {
+        Ord::cmp(self.as_bytes(), other.as_bytes())
+    }
+}
+
 impl TryFrom<ngx_str_t> for &str {
     type Error = core::str::Utf8Error;
 

src/core/string.rs

@@ -1,5 +1,6 @@
 #[cfg(all(not(feature = "std"), feature = "alloc"))]
 use alloc::{borrow::Cow, string::String};
+use core::cmp;
 use core::fmt;
 use core::str::{self, Utf8Error};
 #[cfg(feature = "std")]
@@ -25,6 +26,7 @@ macro_rules! ngx_string {
 /// Representation of a borrowed [Nginx string].
 ///
 /// [Nginx string]: https://nginx.org/en/docs/dev/development_guide.html#string_overview
+#[derive(Hash, PartialEq, Eq, PartialOrd, Ord)]
 #[repr(transparent)]
 pub struct NgxStr([u_char]);
 
@@ -50,6 +52,13 @@ impl NgxStr {
         unsafe { &*(bytes as *const [u8] as *const NgxStr) }
     }
 
+    /// Create a mutable [NgxStr] from a borrowed byte slice.
+    #[inline]
+    pub fn from_bytes_mut(bytes: &mut [u8]) -> &mut Self {
+        // SAFETY: An `NgxStr` is identical to a `[u8]` slice, given `u_char` is an alias for `u8`
+        unsafe { &mut *(bytes as *mut [u8] as *mut NgxStr) }
+    }
+
     /// Access the [`NgxStr`] as a byte slice.
     pub fn as_bytes(&self) -> &[u8] {
         &self.0
@@ -74,24 +83,20 @@ impl NgxStr {
     }
 }
 
-impl<'a> From<&'a [u8]> for &'a NgxStr {
-    fn from(bytes: &'a [u8]) -> Self {
-        NgxStr::from_bytes(bytes)
-    }
-}
-
-impl<'a> From<&'a str> for &'a NgxStr {
-    fn from(s: &'a str) -> Self {
-        NgxStr::from_bytes(s.as_bytes())
-    }
-}
-
 impl AsRef<[u8]> for NgxStr {
+    #[inline]
     fn as_ref(&self) -> &[u8] {
         self.as_bytes()
     }
 }
 
+impl AsMut<[u8]> for NgxStr {
+    #[inline]
+    fn as_mut(&mut self) -> &mut [u8] {
+        &mut self.0
+    }
+}
+
 impl fmt::Debug for NgxStr {
     #[inline]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -115,6 +120,91 @@ impl fmt::Display for NgxStr {
     }
 }
 
+macro_rules! impl_partial_ord_eq_from {
+    ($self:ty, $other:ty) => { impl_partial_ord_eq_from!($self, $other;); };
+
+    ($self:ty, $other:ty; $($args:tt)*) => {
+        impl<'a, $($args)*> From<$other> for &'a NgxStr {
+            #[inline]
+            fn from(other: $other) -> Self {
+                let other: &[u8] = other.as_ref();
+                NgxStr::from_bytes(other)
+            }
+        }
+
+        impl_partial_eq!($self, $other; $($args)*);
+        impl_partial_ord!($self, $other; $($args)*);
+    };
+}
+
+macro_rules! impl_partial_eq {
+    ($self:ty, $other:ty) => { impl_partial_eq!($self, $other;); };
+
+    ($self:ty, $other:ty; $($args:tt)*) => {
+        impl<'a, $($args)*> PartialEq<$other> for $self {
+            #[inline]
+            fn eq(&self, other: &$other) -> bool {
+                let other: &[u8] = other.as_ref();
+                PartialEq::eq(self.as_bytes(), other)
+            }
+        }
+
+        impl<'a, $($args)*> PartialEq<$self> for $other {
+            #[inline]
+            fn eq(&self, other: &$self) -> bool {
+                let this: &[u8] = self.as_ref();
+                PartialEq::eq(this, other.as_bytes())
+            }
+        }
+    };
+}
+
+macro_rules! impl_partial_ord {
+    ($self:ty, $other:ty) => { impl_partial_ord!($self, $other;); };
+
+    ($self:ty, $other:ty; $($args:tt)*) => {
+       impl<'a, $($args)*> PartialOrd<$other> for $self {
+            #[inline]
+            fn partial_cmp(&self, other: &$other) -> Option<cmp::Ordering> {
+                let other: &[u8] = other.as_ref();
+                PartialOrd::partial_cmp(self.as_bytes(), other)
+            }
+        }
+
+        impl<'a, $($args)*> PartialOrd<$self> for $other {
+            #[inline]
+            fn partial_cmp(&self, other: &$self) -> Option<cmp::Ordering> {
+                let this: &[u8] = self.as_ref();
+                PartialOrd::partial_cmp(this, other.as_bytes())
+            }
+        }
+    };
+}
+
+impl_partial_eq!(NgxStr, [u8]);
+impl_partial_eq!(NgxStr, [u8; N]; const N: usize);
+impl_partial_eq!(NgxStr, str);
+impl_partial_eq!(NgxStr, ngx_str_t);
+impl_partial_eq!(&'a NgxStr, ngx_str_t);
+impl_partial_ord!(NgxStr, [u8]);
+impl_partial_ord!(NgxStr, [u8; N]; const N: usize);
+impl_partial_ord!(NgxStr, str);
+impl_partial_ord!(NgxStr, ngx_str_t);
+impl_partial_ord!(&'a NgxStr, ngx_str_t);
+impl_partial_ord_eq_from!(NgxStr, &'a [u8]);
+impl_partial_ord_eq_from!(NgxStr, &'a [u8; N]; const N: usize);
+impl_partial_ord_eq_from!(NgxStr, &'a str);
+
+#[cfg(feature = "alloc")]
+mod _alloc_impls {
+    use super::*;
+    impl_partial_eq!(NgxStr, String);
+    impl_partial_eq!(&'a NgxStr, String);
+    impl_partial_ord!(NgxStr, String);
+    impl_partial_ord!(&'a NgxStr, String);
+    impl_partial_ord_eq_from!(NgxStr, &'a String);
+}
+
 #[cfg(test)]
 mod tests {
     extern crate alloc;
@@ -123,6 +213,32 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn test_comparisons() {
+        let string = "test".to_string();
+        let ngx_string = ngx_str_t {
+            data: string.as_ptr().cast_mut(),
+            len: string.len(),
+        };
+        let ns: &NgxStr = string.as_bytes().into();
+
+        #[cfg(feature = "alloc")]
+        assert_eq!(string, ns);
+        assert_eq!(ngx_string, ns);
+        assert_eq!(string.as_bytes(), ns);
+        assert_eq!(string.as_str(), ns);
+        assert_eq!(b"test", ns);
+        assert_eq!("test", ns);
+
+        #[cfg(feature = "alloc")]
+        assert_eq!(ns, string);
+        assert_eq!(ns, ngx_string);
+        assert_eq!(ns, string.as_bytes());
+        assert_eq!(ns, string.as_str());
+        assert_eq!(ns, b"test");
+        assert_eq!(ns, "test");
+    }
+
     #[test]
     fn test_lifetimes() {
         let a: &NgxStr = "Hello World!".into();