fix every clippy warning possible, remove io_uring as default feature

this project's codebase is so horrendous, im shocked that no one has ran
clippy at all. it had ~200 total lint warnings, some with performance
issues and unsoundness, and the rest just very ugly codebase. i have sat
down and fixed as many of these as possible and i am exhausted.
i haven't fixed some extremely complex ones, but i brought it down from
~200 to ~30.

i have also removed io_uring as a default feature due to it falling
under the same category as linux eBPF: major kernel attack surface for
minimal performance gains. this also makes it impossible to cross-compile
from macOS to Linux because io_uring does not exist in Darwin land.
there are far better ways to achieve better performance than io_uring on
the codebase level.

Signed-off-by: strawberry <june@girlboss.ceo>

src/database/key_value/globals.rs

@@ -256,8 +256,8 @@ lasttimelinecount_cache: {lasttimelinecount_cache}\n"
             ..
         } = new_keys;
 
-        keys.verify_keys.extend(verify_keys.into_iter());
-        keys.old_verify_keys.extend(old_verify_keys.into_iter());
+        keys.verify_keys.extend(verify_keys);
+        keys.old_verify_keys.extend(old_verify_keys);
 
         self.server_signingkeys.insert(
             origin.as_bytes(),

src/database/key_value/rooms/state_accessor.rs

@@ -20,7 +20,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
             let parsed = services()
                 .rooms
                 .state_compressor
-                .parse_compressed_state_event(&compressed)?;
+                .parse_compressed_state_event(compressed)?;
             result.insert(parsed.0, parsed.1);
 
             i += 1;
@@ -49,7 +49,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
             let (_, eventid) = services()
                 .rooms
                 .state_compressor
-                .parse_compressed_state_event(&compressed)?;
+                .parse_compressed_state_event(compressed)?;
             if let Some(pdu) = services().rooms.timeline.get_pdu(&eventid)? {
                 result.insert(
                     (
@@ -101,7 +101,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
                 services()
                     .rooms
                     .state_compressor
-                    .parse_compressed_state_event(&compressed)
+                    .parse_compressed_state_event(compressed)
                     .ok()
                     .map(|(_, id)| id)
             }))

src/database/key_value/rooms/threads.rs

@@ -52,13 +52,13 @@ impl service::rooms::threads::Data for KeyValueDatabase {
             .collect::<Vec<_>>()
             .join(&[0xff][..]);
 
-        self.threadid_userids.insert(&root_id, &users)?;
+        self.threadid_userids.insert(root_id, &users)?;
 
         Ok(())
     }
 
     fn get_participants(&self, root_id: &[u8]) -> Result<Option<Vec<OwnedUserId>>> {
-        if let Some(users) = self.threadid_userids.get(&root_id)? {
+        if let Some(users) = self.threadid_userids.get(root_id)? {
             Ok(Some(
                 users
                     .split(|b| *b == 0xff)

src/database/key_value/rooms/timeline.rs

@@ -39,11 +39,10 @@ impl service::rooms::timeline::Data for KeyValueDatabase {
 
     /// Returns the `count` of this pdu's id.
     fn get_pdu_count(&self, event_id: &EventId) -> Result<Option<PduCount>> {
-        Ok(self
-            .eventid_pduid
+        self.eventid_pduid
             .get(event_id.as_bytes())?
             .map(|pdu_id| pdu_count(&pdu_id))
-            .transpose()?)
+            .transpose()
     }
 
     /// Returns the json of a pdu.
@@ -80,7 +79,7 @@ impl service::rooms::timeline::Data for KeyValueDatabase {
 
     /// Returns the pdu's id.
     fn get_pdu_id(&self, event_id: &EventId) -> Result<Option<Vec<u8>>> {
-        Ok(self.eventid_pduid.get(event_id.as_bytes())?)
+        self.eventid_pduid.get(event_id.as_bytes())
     }
 
     /// Returns the pdu.
@@ -230,7 +229,7 @@ impl service::rooms::timeline::Data for KeyValueDatabase {
         room_id: &RoomId,
         until: PduCount,
     ) -> Result<Box<dyn Iterator<Item = Result<(PduCount, PduEvent)>> + 'a>> {
-        let (prefix, current) = count_to_id(&room_id, until, 1, true)?;
+        let (prefix, current) = count_to_id(room_id, until, 1, true)?;
 
         let user_id = user_id.to_owned();
 
@@ -257,7 +256,7 @@ impl service::rooms::timeline::Data for KeyValueDatabase {
         room_id: &RoomId,
         from: PduCount,
     ) -> Result<Box<dyn Iterator<Item = Result<(PduCount, PduEvent)>> + 'a>> {
-        let (prefix, current) = count_to_id(&room_id, from, 1, false)?;
+        let (prefix, current) = count_to_id(room_id, from, 1, false)?;
 
         let user_id = user_id.to_owned();
 

src/database/mod.rs

@@ -427,14 +427,12 @@ impl KeyValueDatabase {
         }
 
         // If the database has any data, perform data migrations before starting
-        let latest_database_version: u64;
-
         // do not increment the db version if the user is not using sha256_media
-        if cfg!(feature = "sha256_media") {
-            latest_database_version = 14;
+        let latest_database_version = if cfg!(feature = "sha256_media") {
+            14
         } else {
-            latest_database_version = 13;
-        }
+            13
+        };
 
         if services().users.count()? > 0 {
             // MIGRATIONS
@@ -487,6 +485,7 @@ impl KeyValueDatabase {
                         continue;
                     }
 
+                    #[allow(deprecated)]
                     let path = services().globals.get_media_file(&key);
                     let mut file = fs::File::create(path)?;
                     file.write_all(&content)?;