Update how TryFrom implementation are generated

… and remove TryFrom<Cow<'_, str>> implementations

CHANGELOG.md

@@ -4,6 +4,10 @@ Breaking changes
 
 * Removed diesel integration. If you were using it, please comment on the corresponding issue:
   https://github.com/ruma/ruma-identifiers/issues/22
+* Remove `TryFrom<Cow<'_, str>>` implementations for identifier types
+* Update `parse_with_server_name`s signature (instead of `Into<String>` it now requires
+  `Into<Box<str>>` of the id type). This is technically a breaking change, but extremely unlikely
+  to affect any existing code.
 
 # 0.16.1
 

src/event_id.rs

@@ -1,6 +1,6 @@
 //! Matrix event identifiers.
 
-use std::{borrow::Cow, convert::TryFrom, num::NonZeroU8};
+use std::num::NonZeroU8;
 
 use crate::{error::Error, parse_id, validate_id};
 
@@ -87,34 +87,32 @@ impl EventId {
     }
 }
 
-impl TryFrom<Cow<'_, str>> for EventId {
-    type Error = Error;
-
 /// Attempts to create a new Matrix event ID from a string representation.
 ///
 /// If using the original event format as used by Matrix room versions 1 and 2, the string must
-    /// include the leading $ sigil, the localpart, a literal colon, and a valid homeserver
-    /// hostname.
-    fn try_from(event_id: Cow<'_, str>) -> Result<Self, Self::Error> {
-        if event_id.contains(':') {
-            let colon_idx = parse_id(&event_id, &['$'])?;
+/// include the leading $ sigil, the localpart, a literal colon, and a valid homeserver hostname.
+fn try_from<S>(event_id: S) -> Result<EventId, Error>
+where
+    S: AsRef<str> + Into<Box<str>>,
+{
+    if event_id.as_ref().contains(':') {
+        let colon_idx = parse_id(event_id.as_ref(), &['$'])?;
 
-            Ok(Self {
-                full_id: event_id.into_owned().into(),
+        Ok(EventId {
+            full_id: event_id.into(),
             colon_idx: Some(colon_idx),
         })
     } else {
-            validate_id(&event_id, &['$'])?;
+        validate_id(event_id.as_ref(), &['$'])?;
 
-            Ok(Self {
-                full_id: event_id.into_owned().into(),
+        Ok(EventId {
+            full_id: event_id.into(),
             colon_idx: None,
         })
     }
 }
-}
 
-common_impls!(EventId, "a Matrix event ID");
+common_impls!(EventId, try_from, "a Matrix event ID");
 
 #[cfg(test)]
 mod tests {

src/macros.rs

@@ -1,5 +1,5 @@
 macro_rules! common_impls {
-    ($id:ident, $desc:literal) => {
+    ($id:ident, $try_from:ident, $desc:literal) => {
         impl ::std::convert::From<$id> for ::std::string::String {
             fn from(id: $id) -> Self {
                 id.full_id.into()
@@ -10,7 +10,7 @@ macro_rules! common_impls {
             type Error = crate::error::Error;
 
             fn try_from(s: &str) -> Result<Self, Self::Error> {
-                Self::try_from(::std::borrow::Cow::Borrowed(s))
+                $try_from(s)
             }
         }
 
@@ -18,7 +18,7 @@ macro_rules! common_impls {
             type Error = crate::error::Error;
 
             fn try_from(s: String) -> Result<Self, Self::Error> {
-                Self::try_from(::std::borrow::Cow::Owned(s))
+                $try_from(s)
             }
         }
 

src/room_alias_id.rs

@@ -1,6 +1,6 @@
 //! Matrix room alias identifiers.
 
-use std::{borrow::Cow, convert::TryFrom, num::NonZeroU8};
+use std::num::NonZeroU8;
 
 use crate::{error::Error, parse_id};
 
@@ -35,23 +35,22 @@ impl RoomAliasId {
     }
 }
 
-impl TryFrom<Cow<'_, str>> for RoomAliasId {
-    type Error = Error;
-
 /// Attempts to create a new Matrix room alias ID from a string representation.
 ///
 /// The string must include the leading # sigil, the alias, a literal colon, and a server name.
-    fn try_from(room_id: Cow<'_, str>) -> Result<Self, Error> {
-        let colon_idx = parse_id(&room_id, &['#'])?;
+fn try_from<S>(room_id: S) -> Result<RoomAliasId, Error>
+where
+    S: AsRef<str> + Into<Box<str>>,
+{
+    let colon_idx = parse_id(room_id.as_ref(), &['#'])?;
 
-        Ok(Self {
-            full_id: room_id.into_owned().into(),
+    Ok(RoomAliasId {
+        full_id: room_id.into(),
         colon_idx,
     })
 }
-}
 
-common_impls!(RoomAliasId, "a Matrix room alias ID");
+common_impls!(RoomAliasId, try_from, "a Matrix room alias ID");
 
 #[cfg(test)]
 mod tests {

src/room_id.rs

@@ -1,6 +1,6 @@
 //! Matrix room identifiers.
 
-use std::{borrow::Cow, convert::TryFrom, num::NonZeroU8};
+use std::num::NonZeroU8;
 
 use crate::{error::Error, parse_id};
 
@@ -55,24 +55,22 @@ impl RoomId {
     }
 }
 
-impl TryFrom<Cow<'_, str>> for RoomId {
-    type Error = Error;
-
 /// Attempts to create a new Matrix room ID from a string representation.
 ///
-    /// The string must include the leading ! sigil, the localpart, a literal colon, and a server
-    /// name.
-    fn try_from(room_id: Cow<'_, str>) -> Result<Self, Error> {
-        let colon_idx = parse_id(&room_id, &['!'])?;
+/// The string must include the leading ! sigil, the localpart, a literal colon, and a server name.
+fn try_from<S>(room_id: S) -> Result<RoomId, Error>
+where
+    S: AsRef<str> + Into<Box<str>>,
+{
+    let colon_idx = parse_id(room_id.as_ref(), &['!'])?;
 
-        Ok(Self {
-            full_id: room_id.into_owned().into(),
+    Ok(RoomId {
+        full_id: room_id.into(),
         colon_idx,
     })
 }
-}
 
-common_impls!(RoomId, "a Matrix room ID");
+common_impls!(RoomId, try_from, "a Matrix room ID");
 
 #[cfg(test)]
 mod tests {

src/room_id_or_room_alias_id.rs

@@ -1,6 +1,6 @@
 //! Matrix identifiers for places where a room ID or room alias ID are used interchangeably.
 
-use std::{borrow::Cow, convert::TryFrom, hint::unreachable_unchecked, num::NonZeroU8};
+use std::{convert::TryFrom, hint::unreachable_unchecked, num::NonZeroU8};
 
 use crate::{error::Error, parse_id, RoomAliasId, RoomId};
 
@@ -81,24 +81,27 @@ enum Variant {
     RoomAliasId,
 }
 
-impl TryFrom<Cow<'_, str>> for RoomIdOrAliasId {
-    type Error = Error;
-
 /// Attempts to create a new Matrix room ID or a room alias ID from a string representation.
 ///
 /// The string must either include the leading ! sigil, the localpart, a literal colon, and a
 /// valid homeserver host or include the leading # sigil, the alias, a literal colon, and a
 /// valid homeserver host.
-    fn try_from(room_id_or_alias_id: Cow<'_, str>) -> Result<Self, Error> {
-        let colon_idx = parse_id(&room_id_or_alias_id, &['#', '!'])?;
-        Ok(Self {
-            full_id: room_id_or_alias_id.into_owned().into(),
+fn try_from<S>(room_id_or_alias_id: S) -> Result<RoomIdOrAliasId, Error>
+where
+    S: AsRef<str> + Into<Box<str>>,
+{
+    let colon_idx = parse_id(room_id_or_alias_id.as_ref(), &['#', '!'])?;
+    Ok(RoomIdOrAliasId {
+        full_id: room_id_or_alias_id.into(),
         colon_idx,
     })
 }
-}
 
-common_impls!(RoomIdOrAliasId, "a Matrix room ID or room alias ID");
+common_impls!(
+    RoomIdOrAliasId,
+    try_from,
+    "a Matrix room ID or room alias ID"
+);
 
 impl From<RoomId> for RoomIdOrAliasId {
     fn from(RoomId { full_id, colon_idx }: RoomId) -> Self {

src/user_id.rs

@@ -1,6 +1,6 @@
 //! Matrix user identifiers.
 
-use std::{borrow::Cow, convert::TryFrom, num::NonZeroU8};
+use std::num::NonZeroU8;
 
 use crate::{error::Error, is_valid_server_name, parse_id};
 
@@ -59,13 +59,13 @@ impl UserId {
     /// localpart, not the localpart plus the `@` prefix, or the localpart plus server name without
     /// the `@` prefix.
     pub fn parse_with_server_name(
-        id: impl AsRef<str> + Into<String>,
+        id: impl AsRef<str> + Into<Box<str>>,
         server_name: &str,
     ) -> Result<Self, Error> {
         let id_str = id.as_ref();
 
         if id_str.starts_with('@') {
-            Self::try_from(id.into())
+            try_from(id.into())
         } else {
             let is_fully_conforming = localpart_is_fully_comforming(id_str)?;
             if !is_valid_server_name(server_name) {
@@ -98,28 +98,26 @@ impl UserId {
     }
 }
 
-impl TryFrom<Cow<'_, str>> for UserId {
-    type Error = Error;
-
 /// Attempts to create a new Matrix user ID from a string representation.
 ///
-    /// The string must include the leading @ sigil, the localpart, a literal colon, and a server
-    /// name.
-    fn try_from(user_id: Cow<'_, str>) -> Result<Self, Error> {
-        let colon_idx = parse_id(&user_id, &['@'])?;
-        let localpart = &user_id[1..colon_idx.get() as usize];
+/// The string must include the leading @ sigil, the localpart, a literal colon, and a server name.
+fn try_from<S>(user_id: S) -> Result<UserId, Error>
+where
+    S: AsRef<str> + Into<Box<str>>,
+{
+    let colon_idx = parse_id(user_id.as_ref(), &['@'])?;
+    let localpart = &user_id.as_ref()[1..colon_idx.get() as usize];
 
     let is_historical = localpart_is_fully_comforming(localpart)?;
 
-        Ok(Self {
-            full_id: user_id.into_owned().into(),
+    Ok(UserId {
+        full_id: user_id.into(),
         colon_idx,
         is_historical: !is_historical,
     })
 }
-}
 
-common_impls!(UserId, "a Matrix user ID");
+common_impls!(UserId, try_from, "a Matrix user ID");
 
 /// Check whether the given user id localpart is valid and fully conforming
 ///