Switch HttpTryFrom to TryFrom.

Author: David Barsky

src/convert.rs

@@ -167,33 +167,9 @@ impl From<header::InvalidHeaderValueBytes> for Error {
     }
 }
 
-// A crate-private type until we can use !.
-//
-// Being crate-private, we should be able to swap the type out in a
-// backwards compatible way.
-pub enum Never {}
-
-impl From<Never> for Error {
-    fn from(never: Never) -> Error {
-        match never {}
-    }
-}
-
-impl fmt::Debug for Never {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match *self {}
-    }
-}
-
-impl fmt::Display for Never {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match *self {}
-    }
-}
-
-impl error::Error for Never {
-    fn description(&self) -> &str {
-        match *self {}
+impl From<std::convert::Infallible> for Error {
+    fn from(err: std::convert::Infallible) -> Error {
+        match err {}
     }
 }
 

src/error.rs

@@ -1,11 +1,11 @@
 use std::collections::HashMap;
 use std::collections::hash_map::RandomState;
+use std::convert::TryFrom;
 use std::hash::{BuildHasher, Hash, Hasher};
 use std::iter::{FromIterator, FusedIterator};
 use std::marker::PhantomData;
 use std::{fmt, mem, ops, ptr, vec};
 
-use crate::convert::{HttpTryFrom, HttpTryInto};
 use crate::Error;
 
 use super::HeaderValue;
@@ -1815,27 +1815,30 @@ impl<T> FromIterator<(HeaderName, T)> for HeaderMap<T> {
 ///
 /// ```
 /// use std::collections::HashMap;
-/// use http::{HttpTryFrom, header::HeaderMap};
+/// use std::convert::TryInto;
+/// use http::HeaderMap;
 ///
 /// let mut map = HashMap::new();
 /// map.insert("X-Custom-Header".to_string(), "my value".to_string());
 ///
-/// let headers: HeaderMap = HttpTryFrom::try_from(&map).expect("valid headers");
+/// let headers: HeaderMap = (&map).try_into().expect("valid headers");
 /// assert_eq!(headers["X-Custom-Header"], "my value");
 /// ```
-impl<'a, K, V, T> HttpTryFrom<&'a HashMap<K, V>> for HeaderMap<T>
+impl<'a, K, V, T> TryFrom<&'a HashMap<K, V>> for HeaderMap<T>
     where
         K: Eq + Hash,
-        HeaderName: HttpTryFrom<&'a K>,
-        T: HttpTryFrom<&'a V>
+        HeaderName: TryFrom<&'a K>,
+        <HeaderName as TryFrom<&'a K>>::Error: Into<crate::Error>,
+        T: TryFrom<&'a V>,
+        T::Error: Into<crate::Error>,
 {
     type Error = Error;
 
     fn try_from(c: &'a HashMap<K, V>) -> Result<Self, Self::Error> {
         c.into_iter()
-            .map(|(k, v)| {
-                let name = k.http_try_into()?;
-                let value = v.http_try_into()?;
+            .map(|(k, v)| -> crate::Result<(HeaderName, T)> {
+                let name = TryFrom::try_from(k).map_err(Into::into)?;
+                let value = TryFrom::try_from(v).map_err(Into::into)?;
                 Ok((name, value))
             })
             .collect()

src/header/map.rs

@@ -1,9 +1,9 @@
 use crate::byte_str::ByteStr;
-use crate::HttpTryFrom;
 use bytes::{Bytes, BytesMut};
 
 use std::borrow::Borrow;
 use std::error::Error;
+use std::convert::{TryFrom};
 use std::hash::{Hash, Hasher};
 use std::str::FromStr;
 use std::{fmt, mem};
@@ -1888,40 +1888,31 @@ impl From<HeaderName> for Bytes {
     }
 }
 
-impl<'a> HttpTryFrom<&'a HeaderName> for HeaderName {
-    type Error = crate::error::Never;
-
-    #[inline]
-    fn try_from(t: &'a HeaderName) -> Result<Self, Self::Error> {
-        Ok(t.clone())
-    }
-}
-
-impl<'a> HttpTryFrom<&'a str> for HeaderName {
+impl<'a> TryFrom<&'a str> for HeaderName {
     type Error = InvalidHeaderName;
     #[inline]
     fn try_from(s: &'a str) -> Result<Self, Self::Error> {
         Self::from_bytes(s.as_bytes())
     }
 }
 
-impl<'a> HttpTryFrom<&'a String> for HeaderName {
+impl<'a> TryFrom<&'a String> for HeaderName {
     type Error = InvalidHeaderName;
     #[inline]
     fn try_from(s: &'a String) -> Result<Self, Self::Error> {
         Self::from_bytes(s.as_bytes())
     }
 }
 
-impl<'a> HttpTryFrom<&'a [u8]> for HeaderName {
+impl<'a> TryFrom<&'a [u8]> for HeaderName {
     type Error = InvalidHeaderName;
     #[inline]
     fn try_from(s: &'a [u8]) -> Result<Self, Self::Error> {
         Self::from_bytes(s)
     }
 }
 
-impl HttpTryFrom<Bytes> for HeaderName {
+impl TryFrom<Bytes> for HeaderName {
     type Error = InvalidHeaderNameBytes;
     #[inline]
     fn try_from(bytes: Bytes) -> Result<Self, Self::Error> {

src/header/name.rs

@@ -1,11 +1,10 @@
 use bytes::{Bytes, BytesMut};
 
+use std::convert::TryFrom;
 use std::error::Error;
 use std::str::FromStr;
 use std::{cmp, fmt, mem, str};
 
-use crate::convert::HttpTryFrom;
-use crate::error::Never;
 use crate::header::name::HeaderName;
 
 /// Represents an HTTP header field value.
@@ -397,15 +396,6 @@ macro_rules! from_integers {
             }
         }
 
-        impl HttpTryFrom<$t> for HeaderValue {
-            type Error = Never;
-
-            #[inline]
-            fn try_from(num: $t) -> Result<Self, Self::Error> {
-                Ok(num.into())
-            }
-        }
-
         #[test]
         fn $name() {
             let n: $t = 55;
@@ -499,16 +489,7 @@ impl<'a> From<&'a HeaderValue> for HeaderValue {
     }
 }
 
-impl<'a> HttpTryFrom<&'a HeaderValue> for HeaderValue {
-    type Error = crate::error::Never;
-
-    #[inline]
-    fn try_from(t: &'a HeaderValue) -> Result<Self, Self::Error> {
-        Ok(t.clone())
-    }
-}
-
-impl<'a> HttpTryFrom<&'a str> for HeaderValue {
+impl<'a> TryFrom<&'a str> for HeaderValue {
     type Error = InvalidHeaderValue;
 
     #[inline]
@@ -517,15 +498,15 @@ impl<'a> HttpTryFrom<&'a str> for HeaderValue {
     }
 }
 
-impl<'a> HttpTryFrom<&'a String> for HeaderValue {
+impl<'a> TryFrom<&'a String> for HeaderValue {
     type Error = InvalidHeaderValue;
     #[inline]
     fn try_from(s: &'a String) -> Result<Self, Self::Error> {
         Self::from_bytes(s.as_bytes())
     }
 }
 
-impl<'a> HttpTryFrom<&'a [u8]> for HeaderValue {
+impl<'a> TryFrom<&'a [u8]> for HeaderValue {
     type Error = InvalidHeaderValue;
 
     #[inline]
@@ -534,7 +515,7 @@ impl<'a> HttpTryFrom<&'a [u8]> for HeaderValue {
     }
 }
 
-impl HttpTryFrom<String> for HeaderValue {
+impl TryFrom<String> for HeaderValue {
     type Error = InvalidHeaderValueBytes;
 
     #[inline]
@@ -543,7 +524,7 @@ impl HttpTryFrom<String> for HeaderValue {
     }
 }
 
-impl HttpTryFrom<Bytes> for HeaderValue {
+impl TryFrom<Bytes> for HeaderValue {
     type Error = InvalidHeaderValueBytes;
 
     #[inline]
@@ -552,16 +533,6 @@ impl HttpTryFrom<Bytes> for HeaderValue {
     }
 }
 
-impl HttpTryFrom<HeaderName> for HeaderValue {
-    type Error = InvalidHeaderValue;
-
-    #[inline]
-    fn try_from(name: HeaderName) -> Result<Self, Self::Error> {
-        // Infallable as header names have the same validations
-        Ok(name.into())
-    }
-}
-
 #[cfg(test)]
 mod try_from_header_name_tests {
     use super::*;

src/header/value.rs

@@ -176,11 +176,9 @@ pub mod uri;
 pub mod version;
 
 mod byte_str;
-mod convert;
 mod error;
 mod extensions;
 
-pub use crate::convert::HttpTryFrom;
 pub use crate::error::{Error, Result};
 pub use crate::extensions::Extensions;
 #[doc(no_inline)]

src/lib.rs

@@ -16,11 +16,11 @@
 //! ```
 
 use self::Inner::*;
-use crate::HttpTryFrom;
 
 use std::convert::AsRef;
 use std::error::Error;
 use std::str::FromStr;
+use std::convert::TryFrom;
 use std::{fmt, str};
 
 /// The Request Method (VERB)
@@ -322,16 +322,7 @@ impl<'a> From<&'a Method> for Method {
     }
 }
 
-impl<'a> HttpTryFrom<&'a Method> for Method {
-    type Error = crate::error::Never;
-
-    #[inline]
-    fn try_from(t: &'a Method) -> Result<Self, Self::Error> {
-        Ok(t.clone())
-    }
-}
-
-impl<'a> HttpTryFrom<&'a [u8]> for Method {
+impl<'a> TryFrom<&'a [u8]> for Method {
     type Error = InvalidMethod;
 
     #[inline]
@@ -340,12 +331,12 @@ impl<'a> HttpTryFrom<&'a [u8]> for Method {
     }
 }
 
-impl<'a> HttpTryFrom<&'a str> for Method {
+impl<'a> TryFrom<&'a str> for Method {
     type Error = InvalidMethod;
 
     #[inline]
     fn try_from(t: &'a str) -> Result<Self, Self::Error> {
-        HttpTryFrom::try_from(t.as_bytes())
+        TryFrom::try_from(t.as_bytes())
     }
 }
 
@@ -354,7 +345,7 @@ impl FromStr for Method {
 
     #[inline]
     fn from_str(t: &str) -> Result<Self, Self::Err> {
-        HttpTryFrom::try_from(t)
+        TryFrom::try_from(t)
     }
 }