identifiers: Remove runtime checks for server_name extraction

crates/ruma-identifiers/src/event_id.rs

@@ -1,7 +1,5 @@
 //! Matrix event identifiers.
 
-use std::convert::TryInto;
-
 use crate::ServerName;
 
 /// A Matrix event ID.
@@ -68,7 +66,7 @@ impl EventId {
     ///
     /// Only applicable to events in the original format as used by Matrix room versions 1 and 2.
     pub fn server_name(&self) -> Option<&ServerName> {
-        self.colon_idx().map(|idx| self.as_str()[idx as usize + 1..].try_into().unwrap())
+        self.colon_idx().map(|idx| ServerName::from_borrowed(&self.as_str()[idx + 1..]))
     }
 
     fn colon_idx(&self) -> Option<usize> {

crates/ruma-identifiers/src/macros.rs

@@ -27,7 +27,7 @@ macro_rules! partial_eq_string {
 macro_rules! opaque_identifier_common_impls {
     ($id:ty) => {
         impl $id {
-            fn from_borrowed(s: &str) -> &Self {
+            pub(super) fn from_borrowed(s: &str) -> &Self {
                 unsafe { std::mem::transmute(s) }
             }
 

crates/ruma-identifiers/src/mxc_uri.rs

@@ -2,7 +2,7 @@
 //!
 //! [MXC URI]: https://matrix.org/docs/spec/client_server/r0.6.1#mxc-uri
 
-use std::{convert::TryInto, num::NonZeroU8};
+use std::num::NonZeroU8;
 
 use ruma_identifiers_validation::{error::MxcUriError, mxc_uri::validate};
 
@@ -36,7 +36,7 @@ impl MxcUri {
     pub fn parts(&self) -> Result<(&ServerName, &str)> {
         self.extract_slash_idx().map(|idx| {
             (
-                self.as_str()[6..idx.get() as usize].try_into().unwrap(),
+                ServerName::from_borrowed(&self.as_str()[6..idx.get() as usize]),
                 &self.as_str()[idx.get() as usize + 1..],
             )
         })

crates/ruma-identifiers/src/room_alias_id.rs

@@ -1,7 +1,5 @@
 //! Matrix room alias identifiers.
 
-use std::convert::TryInto;
-
 use crate::{server_name::ServerName, EventId, MatrixToRef};
 
 /// A Matrix room alias ID.
@@ -31,7 +29,7 @@ impl RoomAliasId {
 
     /// Returns the server name of the room alias ID.
     pub fn server_name(&self) -> &ServerName {
-        self.as_str()[self.colon_idx() + 1..].try_into().unwrap()
+        ServerName::from_borrowed(&self.as_str()[self.colon_idx() + 1..])
     }
 
     /// Create a `matrix.to` reference for this room alias ID.

crates/ruma-identifiers/src/room_id.rs

@@ -1,7 +1,5 @@
 //! Matrix room identifiers.
 
-use std::convert::TryInto;
-
 use crate::{EventId, MatrixToRef, ServerName};
 
 /// A Matrix room ID.
@@ -40,7 +38,7 @@ impl RoomId {
 
     /// Returns the server name of the room ID.
     pub fn server_name(&self) -> &ServerName {
-        self.as_str()[self.colon_idx() + 1..].try_into().unwrap()
+        ServerName::from_borrowed(&self.as_str()[self.colon_idx() + 1..])
     }
 
     /// Create a `matrix.to` reference for this room ID.

crates/ruma-identifiers/src/room_or_room_alias_id.rs

@@ -43,7 +43,7 @@ impl RoomOrAliasId {
 
     /// Returns the server name of the room (alias) ID.
     pub fn server_name(&self) -> &ServerName {
-        self.as_str()[self.colon_idx() + 1..].try_into().unwrap()
+        ServerName::from_borrowed(&self.as_str()[self.colon_idx() + 1..])
     }
 
     /// Whether this is a room id (starts with `'!'`)

crates/ruma-identifiers/src/user_id.rs

@@ -1,7 +1,5 @@
 //! Matrix user identifiers.
 
-use std::convert::TryInto;
-
 use crate::{MatrixToRef, ServerName};
 
 /// A Matrix user ID.
@@ -60,7 +58,7 @@ impl UserId {
 
     /// Returns the server name of the user ID.
     pub fn server_name(&self) -> &ServerName {
-        self.as_str()[self.colon_idx() as usize + 1..].try_into().unwrap()
+        ServerName::from_borrowed(&self.as_str()[self.colon_idx() + 1..])
     }
 
     /// Whether this user ID is a historical one.