introduce HeaderValue type to replace use of String

src/types.rs

@@ -12,6 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::fmt;
+use std::hash::{Hash, Hasher};
+
 use crate::traits::*;
 
 pub type NewRootContext = fn(context_id: u32) -> Box<dyn RootContext>;
@@ -77,3 +80,261 @@ pub enum PeerType {
 }
 
 pub type Bytes = Vec<u8>;
+
+/// Represents an HTTP header value that is not necessarily a UTF-8 encoded string.
+#[derive(Eq)]
+pub struct HeaderValue {
+    inner: Result<String, Bytes>,
+}
+
+impl HeaderValue {
+    fn new(inner: Result<String, Bytes>) -> Self {
+        HeaderValue { inner }
+    }
+
+    pub fn into_vec(self) -> Vec<u8> {
+        match self.inner {
+            Ok(string) => string.into_bytes(),
+            Err(bytes) => bytes,
+        }
+    }
+
+    pub fn into_string_or_vec(self) -> Result<String, Vec<u8>> {
+        self.inner
+    }
+}
+
+impl From<Vec<u8>> for HeaderValue {
+    #[inline]
+    fn from(data: Vec<u8>) -> Self {
+        Self::new(match String::from_utf8(data) {
+            Ok(string) => Ok(string),
+            Err(err) => Err(err.into_bytes()),
+        })
+    }
+}
+
+impl From<&[u8]> for HeaderValue {
+    fn from(data: &[u8]) -> Self {
+        data.to_owned().into()
+    }
+}
+
+impl From<String> for HeaderValue {
+    #[inline]
+    fn from(string: String) -> Self {
+        Self::new(Ok(string))
+    }
+}
+
+impl From<&str> for HeaderValue {
+    fn from(data: &str) -> Self {
+        data.to_owned().into()
+    }
+}
+
+impl fmt::Display for HeaderValue {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.inner {
+            Ok(ref string) => fmt::Display::fmt(string, f),
+            Err(ref bytes) => fmt::Debug::fmt(bytes, f),
+        }
+    }
+}
+
+impl fmt::Debug for HeaderValue {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.inner {
+            Ok(ref string) => fmt::Debug::fmt(string, f),
+            Err(ref bytes) => fmt::Debug::fmt(bytes, f),
+        }
+    }
+}
+
+impl AsRef<[u8]> for HeaderValue {
+    #[inline]
+    fn as_ref(&self) -> &[u8] {
+        match self.inner {
+            Ok(ref string) => string.as_bytes(),
+            Err(ref bytes) => bytes.as_slice(),
+        }
+    }
+}
+
+impl PartialEq for HeaderValue {
+    #[inline]
+    fn eq(&self, other: &HeaderValue) -> bool {
+        self.inner == other.inner
+    }
+}
+
+impl PartialEq<String> for HeaderValue {
+    #[inline]
+    fn eq(&self, other: &String) -> bool {
+        self.as_ref() == other.as_bytes()
+    }
+}
+
+impl PartialEq<Vec<u8>> for HeaderValue {
+    #[inline]
+    fn eq(&self, other: &Vec<u8>) -> bool {
+        self.as_ref() == other.as_slice()
+    }
+}
+
+impl PartialEq<&str> for HeaderValue {
+    #[inline]
+    fn eq(&self, other: &&str) -> bool {
+        self.as_ref() == other.as_bytes()
+    }
+}
+
+impl PartialEq<&[u8]> for HeaderValue {
+    #[inline]
+    fn eq(&self, other: &&[u8]) -> bool {
+        self.as_ref() == *other
+    }
+}
+
+impl PartialEq<HeaderValue> for String {
+    #[inline]
+    fn eq(&self, other: &HeaderValue) -> bool {
+        *other == *self
+    }
+}
+
+impl PartialEq<HeaderValue> for Vec<u8> {
+    #[inline]
+    fn eq(&self, other: &HeaderValue) -> bool {
+        *other == *self
+    }
+}
+
+impl PartialEq<HeaderValue> for &str {
+    #[inline]
+    fn eq(&self, other: &HeaderValue) -> bool {
+        *other == *self
+    }
+}
+
+impl PartialEq<HeaderValue> for &[u8] {
+    #[inline]
+    fn eq(&self, other: &HeaderValue) -> bool {
+        *other == *self
+    }
+}
+
+impl Hash for HeaderValue {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        match self.inner {
+            Ok(ref string) => Hash::hash(string, state),
+            Err(ref bytes) => Hash::hash(bytes, state),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::collections::hash_map::DefaultHasher;
+    use std::hash::{Hash, Hasher};
+
+    #[test]
+    fn test_header_value_display_string() {
+        let string: HeaderValue = String::from("utf-8 encoded string").into();
+
+        assert_eq!(format!("{}", string), "utf-8 encoded string");
+    }
+
+    #[test]
+    fn test_header_value_display_bytes() {
+        let bytes: HeaderValue = vec![144u8, 145u8, 146u8].into();
+
+        assert_eq!(format!("{}", bytes), "[144, 145, 146]");
+    }
+
+    #[test]
+    fn test_header_value_debug_string() {
+        let string: HeaderValue = String::from("utf-8 encoded string").into();
+
+        assert_eq!(format!("{:?}", string), "\"utf-8 encoded string\"");
+    }
+
+    #[test]
+    fn test_header_value_debug_bytes() {
+        let bytes: HeaderValue = vec![144u8, 145u8, 146u8].into();
+
+        assert_eq!(format!("{:?}", bytes), "[144, 145, 146]");
+    }
+
+    #[test]
+    fn test_header_value_as_ref() {
+        fn receive<T>(value: T)
+        where
+            T: AsRef<[u8]>,
+        {
+            value.as_ref();
+        }
+
+        let string: HeaderValue = String::from("utf-8 encoded string").into();
+        receive(string);
+
+        let bytes: HeaderValue = vec![144u8, 145u8, 146u8].into();
+        receive(bytes);
+    }
+
+    #[test]
+    fn test_header_value_eq_string() {
+        let string: HeaderValue = String::from("utf-8 encoded string").into();
+
+        assert_eq!(string, "utf-8 encoded string");
+        assert_eq!(string, b"utf-8 encoded string" as &[u8]);
+
+        assert_eq!("utf-8 encoded string", string);
+        assert_eq!(b"utf-8 encoded string" as &[u8], string);
+
+        assert_eq!(string, string);
+    }
+
+    #[test]
+    fn test_header_value_eq_bytes() {
+        let bytes: HeaderValue = vec![144u8, 145u8, 146u8].into();
+
+        assert_eq!(bytes, vec![144u8, 145u8, 146u8]);
+        assert_eq!(bytes, b"\x90\x91\x92" as &[u8]);
+
+        assert_eq!(vec![144u8, 145u8, 146u8], bytes);
+        assert_eq!(b"\x90\x91\x92" as &[u8], bytes);
+
+        assert_eq!(bytes, bytes);
+    }
+
+    fn hash<T: Hash>(t: &T) -> u64 {
+        let mut h = DefaultHasher::new();
+        t.hash(&mut h);
+        h.finish()
+    }
+
+    #[test]
+    fn test_header_value_hash_string() {
+        let string: HeaderValue = String::from("utf-8 encoded string").into();
+
+        assert_eq!(hash(&string), hash(&"utf-8 encoded string"));
+        assert_ne!(hash(&string), hash(&b"utf-8 encoded string"));
+
+        assert_eq!(hash(&"utf-8 encoded string"), hash(&string));
+        assert_ne!(hash(&b"utf-8 encoded string"), hash(&string));
+    }
+
+    #[test]
+    fn test_header_value_hash_bytes() {
+        let bytes: HeaderValue = vec![144u8, 145u8, 146u8].into();
+
+        assert_eq!(hash(&bytes), hash(&vec![144u8, 145u8, 146u8]));
+        assert_eq!(hash(&bytes), hash(&[144u8, 145u8, 146u8]));
+
+        assert_eq!(hash(&vec![144u8, 145u8, 146u8]), hash(&bytes));
+        assert_eq!(hash(&[144u8, 145u8, 146u8]), hash(&bytes));
+    }
+}