fix(lib): route on the full four-byte message code

Dispatch read one byte of the code, so a code with a non-zero high byte
was handled as its low byte. Message::get_message_code now reads the
whole little-endian uint32 and handlers register by u32. PeerInit and
PierceFirewall, the only frames with a one-byte code, get their own
accessor for the listener's first frame.

soulseek-rs-lib/examples/stress.rs

@@ -481,7 +481,7 @@ impl SeederState {
             let Ok(init) = read_framed(&mut p) else {
                 return;
             };
-            if init.get_message_code() != 1 {
+            if init.get_init_code() != 1 {
                 return;
             }
         }
@@ -735,7 +735,7 @@ fn accept_file_connection(
         let Ok(mut init) = read_framed(&mut stream) else {
             continue;
         };
-        if init.get_message_code() != 1 {
+        if init.get_init_code() != 1 {
             continue;
         }
         init.set_pointer(5);

soulseek-rs-lib/src/actor/peer_actor.rs

@@ -535,7 +535,7 @@ impl PeerActor {
                         message
                             .get_message_name(
                                 MessageType::Peer,
-                                u32::from(message.get_message_code())
+                                message.get_message_code()
                             )
                             .map_err(|e| e.to_string())
                     );

soulseek-rs-lib/src/actor/server_actor.rs

@@ -803,7 +803,7 @@ impl ServerActor {
                         message
                             .get_message_name(
                                 MessageType::Server,
-                                u32::from(message.get_message_code())
+                                message.get_message_code()
                             )
                             .map_err(|e| e.to_string())
                     );

soulseek-rs-lib/src/dispatcher.rs

@@ -37,3 +37,40 @@ impl<Op> MessageDispatcher<Op> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::message::MessageHandler;
+    use std::sync::mpsc::channel;
+
+    struct Echo(u32);
+
+    impl MessageHandler<u32> for Echo {
+        fn get_code(&self) -> u32 {
+            self.0
+        }
+        fn handle(&self, _: &mut Message, sender: Sender<u32>) {
+            let _ = sender.send(self.0);
+        }
+    }
+
+    fn framed(code: u32) -> Message {
+        Message::new_with_data(Message::new().write_int32(code).get_buffer())
+    }
+
+    #[test]
+    fn a_code_above_255_is_not_confused_with_its_low_byte() {
+        let (sender, received) = channel();
+        let mut handlers = Handlers::new();
+        handlers.register_handler(Echo(1));
+        handlers.register_handler(Echo(1001));
+        let dispatcher =
+            MessageDispatcher::new("test".to_string(), sender, handlers);
+
+        dispatcher.dispatch(&mut framed(257));
+        dispatcher.dispatch(&mut framed(1001));
+
+        assert_eq!(received.try_iter().collect::<Vec<_>>(), [1001]);
+    }
+}

soulseek-rs-lib/src/message/handlers.rs

@@ -4,11 +4,11 @@ use crate::message::Message;
 use std::sync::mpsc::Sender;
 
 pub trait MessageHandler<Op>: Send {
-    fn get_code(&self) -> u8;
+    fn get_code(&self) -> u32;
     fn handle(&self, message: &mut Message, sender: Sender<Op>);
 }
 pub struct Handlers<Op> {
-    handlers: HashMap<u8, Box<dyn MessageHandler<Op> + Send>>,
+    handlers: HashMap<u32, Box<dyn MessageHandler<Op> + Send>>,
 }
 
 impl<Op> Default for Handlers<Op> {
@@ -35,7 +35,7 @@ impl<Op> Handlers<Op> {
     #[must_use]
     pub fn get_handler(
         &self,
-        code: u8,
+        code: u32,
     ) -> Option<&(dyn MessageHandler<Op> + Send)> {
         self.handlers.get(&code).map(|v| &**v)
     }

soulseek-rs-lib/src/message/mod.rs

@@ -51,21 +51,19 @@ impl Message {
         }
     }
 
-    #[allow(dead_code)]
     #[must_use]
-    pub fn get_message_code_u32(&self) -> u32 {
+    pub fn get_message_code(&self) -> u32 {
         if self.data.len() < 8 {
             return 0;
         }
         self.data[4..8].try_into().map_or(0, u32::from_le_bytes)
     }
 
+    /// The one-byte code of a peer init frame (PierceFirewall 0, PeerInit 1),
+    /// the only messages whose code is not four bytes wide.
     #[must_use]
-    pub fn get_message_code(&self) -> u8 {
-        if self.data.len() <= 4 {
-            return 0;
-        }
-        self.data[4]
+    pub fn get_init_code(&self) -> u8 {
+        self.data.get(4).copied().unwrap_or(0)
     }
 
     #[must_use]
@@ -388,10 +386,19 @@ fn read_string_with_missing_length_prefix_does_not_panic() {
 #[test]
 fn get_message_code_on_short_message_does_not_panic() {
     // A zero-length frame drains to exactly the 4-byte length prefix, leaving
-    // no room for a message code at data[4].
+    // no room for a code after it.
     let msg = Message::new_with_data(vec![0, 0, 0, 0]);
     assert_eq!(msg.get_message_code(), 0);
-    assert_eq!(msg.get_message_code_u32(), 0);
+    assert_eq!(msg.get_init_code(), 0);
+}
+
+#[test]
+fn an_init_frame_reads_its_one_byte_code() {
+    let init = Message::new_with_data(
+        Message::new().write_int8(1).write_string("ab").get_buffer(),
+    );
+    assert_eq!(init.get_init_code(), 1);
+    assert_ne!(init.get_message_code(), 1);
 }
 
 #[test]

soulseek-rs-lib/src/message/peer/file_search_response.rs

@@ -50,7 +50,7 @@ pub fn build_file_search_response(
 
 pub struct FileSearchResponse;
 impl MessageHandler<PeerMessage> for FileSearchResponse {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         9
     }
     fn handle(&self, message: &mut Message, sender: Sender<PeerMessage>) {

soulseek-rs-lib/src/message/peer/get_share_file_list.rs

@@ -8,7 +8,7 @@ use std::sync::mpsc::Sender;
 /// owns the shares) builds the real SharedFileListResponse in reply.
 pub struct GetShareFileList;
 impl MessageHandler<PeerMessage> for GetShareFileList {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         4
     }
     fn handle(&self, _message: &mut Message, sender: Sender<PeerMessage>) {

soulseek-rs-lib/src/message/peer/peer_init.rs

@@ -8,7 +8,7 @@ use crate::{
 
 pub struct PeerInit;
 impl MessageHandler<PeerMessage> for PeerInit {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         1
     }
 

soulseek-rs-lib/src/message/peer/place_in_queue_request.rs

@@ -12,7 +12,7 @@ use std::sync::mpsc::Sender;
 pub struct PlaceInQueueRequest;
 
 impl MessageHandler<PeerMessage> for PlaceInQueueRequest {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         51
     }
 

soulseek-rs-lib/src/message/peer/place_in_queue_response.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 pub struct PlaceInQueueResponse;
 
 impl MessageHandler<PeerMessage> for PlaceInQueueResponse {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         44
     }
 

soulseek-rs-lib/src/message/peer/queue_upload.rs

@@ -8,7 +8,7 @@ use std::sync::mpsc::Sender;
 pub struct QueueUploadHandler;
 
 impl MessageHandler<PeerMessage> for QueueUploadHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         43
     }
 

soulseek-rs-lib/src/message/peer/shared_file_list.rs

@@ -17,7 +17,7 @@ pub struct SharedDirectory {
 /// Receives a peer's `SharedFileListResponse` (peer code 5) when browsing them.
 pub struct SharedFileListResponseHandler;
 impl MessageHandler<PeerMessage> for SharedFileListResponseHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         5
     }
     fn handle(&self, message: &mut Message, sender: Sender<PeerMessage>) {

soulseek-rs-lib/src/message/peer/transfer_request.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 
 pub struct TransferRequest;
 impl MessageHandler<PeerMessage> for TransferRequest {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         40
     }
     fn handle(&self, message: &mut Message, sender: Sender<PeerMessage>) {

soulseek-rs-lib/src/message/peer/transfer_response.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 pub struct TransferResponse;
 
 impl MessageHandler<PeerMessage> for TransferResponse {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         41
     }
 

soulseek-rs-lib/src/message/peer/upload_denied.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 
 pub struct UploadDeniedHandler;
 impl MessageHandler<PeerMessage> for UploadDeniedHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         50
     }
     fn handle(&self, message: &mut Message, sender: Sender<PeerMessage>) {

soulseek-rs-lib/src/message/peer/upload_failed.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 
 pub struct UploadFailedHandler;
 impl MessageHandler<PeerMessage> for UploadFailedHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         46
     }
     fn handle(&self, message: &mut Message, sender: Sender<PeerMessage>) {

soulseek-rs-lib/src/message/server/connect_to_peer.rs

@@ -5,7 +5,7 @@ use std::sync::mpsc::Sender;
 pub struct ConnectToPeerHandler;
 
 impl MessageHandler<ServerMessage> for ConnectToPeerHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         18
     }
     fn handle(&self, message: &mut Message, sender: Sender<ServerMessage>) {

soulseek-rs-lib/src/message/server/excluded_search_phrases.rs

@@ -8,7 +8,7 @@ use std::sync::mpsc::Sender;
 pub struct ExcludedSearchPhrasesHandler;
 
 impl MessageHandler<ServerMessage> for ExcludedSearchPhrasesHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         160
     }
 

soulseek-rs-lib/src/message/server/file_search.rs

@@ -9,7 +9,7 @@ use crate::{
 pub struct FileSearchHandler;
 
 impl MessageHandler<ServerMessage> for FileSearchHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         26
     }
     fn handle(&self, message: &mut Message, sender: Sender<ServerMessage>) {

soulseek-rs-lib/src/message/server/get_peer_address.rs

@@ -5,7 +5,7 @@ use std::sync::mpsc::Sender;
 pub struct GetPeerAddressHandler;
 
 impl MessageHandler<ServerMessage> for GetPeerAddressHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         3
     }
 

soulseek-rs-lib/src/message/server/join_room.rs

@@ -8,7 +8,7 @@ use std::sync::mpsc::Sender;
 pub struct JoinRoomHandler;
 
 impl MessageHandler<ServerMessage> for JoinRoomHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         14
     }
 

soulseek-rs-lib/src/message/server/leave_room.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 pub struct LeaveRoomHandler;
 
 impl MessageHandler<ServerMessage> for LeaveRoomHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         15
     }
 

soulseek-rs-lib/src/message/server/login.rs

@@ -8,7 +8,7 @@ use crate::message::MessageHandler;
 pub struct LoginHandler;
 
 impl MessageHandler<ServerMessage> for LoginHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         1
     }
 

soulseek-rs-lib/src/message/server/message_factory.rs

@@ -336,7 +336,7 @@ fn a_transfer_denial_carries_the_token_and_the_reason() {
     let message =
         MessageFactory::build_transfer_denial_message(555, "Cancelled");
     let mut decoded = Message::new_with_data(message.get_buffer());
-    assert_eq!(decoded.get_message_code_u32(), 41);
+    assert_eq!(decoded.get_message_code(), 41);
     decoded.set_pointer(8);
     assert_eq!(decoded.read_int32(), 555);
     assert!(!decoded.read_bool());

soulseek-rs-lib/src/message/server/message_user.rs

@@ -8,7 +8,7 @@ use std::sync::mpsc::Sender;
 pub struct MessageUser;
 
 impl MessageHandler<ServerMessage> for MessageUser {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         22
     }
 

soulseek-rs-lib/src/message/server/parent_min_speed.rs

@@ -9,7 +9,7 @@ use crate::{
 pub struct ParentMinSpeedHandler;
 
 impl MessageHandler<ServerMessage> for ParentMinSpeedHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         83
     }
 

soulseek-rs-lib/src/message/server/parent_speed_ratio.rs

@@ -10,7 +10,7 @@ pub struct ParentSpeedRatioHandler;
 
 // The server sends us a speed ratio determining the number of children we can have in the distributed network. The maximum number of children is our upload speed divided by the speed ratio.
 impl MessageHandler<ServerMessage> for ParentSpeedRatioHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         84
     }
 

soulseek-rs-lib/src/message/server/privileged_users.rs

@@ -14,7 +14,7 @@ use crate::{
 pub struct PrivilegedUsersHandler;
 
 impl MessageHandler<ServerMessage> for PrivilegedUsersHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         69
     }
 
@@ -37,7 +37,7 @@ impl MessageHandler<ServerMessage> for PrivilegedUsersHandler {
 pub struct CheckPrivilegesHandler;
 
 impl MessageHandler<ServerMessage> for CheckPrivilegesHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         92
     }
 

soulseek-rs-lib/src/message/server/relogged.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 pub struct ReloggedHandler;
 
 impl MessageHandler<ServerMessage> for ReloggedHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         41
     }
 

soulseek-rs-lib/src/message/server/room_list.rs

@@ -8,7 +8,7 @@ use std::sync::mpsc::Sender;
 pub struct RoomListHandler;
 
 impl MessageHandler<ServerMessage> for RoomListHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         64
     }
 

soulseek-rs-lib/src/message/server/say_chatroom.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 pub struct SayChatroomHandler;
 
 impl MessageHandler<ServerMessage> for SayChatroomHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         13
     }
 

soulseek-rs-lib/src/message/server/user_info.rs

@@ -12,7 +12,7 @@ use std::sync::mpsc::Sender;
 pub struct GetUserStatusHandler;
 
 impl MessageHandler<ServerMessage> for GetUserStatusHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         7
     }
 
@@ -33,7 +33,7 @@ impl MessageHandler<ServerMessage> for GetUserStatusHandler {
 pub struct GetUserStatsHandler;
 
 impl MessageHandler<ServerMessage> for GetUserStatsHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         36
     }
 

soulseek-rs-lib/src/message/server/user_joined_room.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 pub struct UserJoinedRoomHandler;
 
 impl MessageHandler<ServerMessage> for UserJoinedRoomHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         16
     }
 

soulseek-rs-lib/src/message/server/user_left_room.rs

@@ -7,7 +7,7 @@ use std::sync::mpsc::Sender;
 pub struct UserLeftRoomHandler;
 
 impl MessageHandler<ServerMessage> for UserLeftRoomHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         17
     }
 

soulseek-rs-lib/src/message/server/watch_user.rs

@@ -21,7 +21,7 @@ use std::sync::mpsc::Sender;
 pub struct WatchUserHandler;
 
 impl MessageHandler<ServerMessage> for WatchUserHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         5
     }
 

soulseek-rs-lib/src/message/server/wish_list_interval.rs

@@ -13,7 +13,7 @@ use crate::{
 pub struct WishListIntervalHandler;
 
 impl MessageHandler<ServerMessage> for WishListIntervalHandler {
-    fn get_code(&self) -> u8 {
+    fn get_code(&self) -> u32 {
         104
     }
 

soulseek-rs-lib/src/peer/listen.rs

@@ -360,7 +360,7 @@ fn handle_incoming_connection(
 
     // A firewalled peer brokered through the server connects back with a
     // PierceFirewall (code 0) instead of a PeerInit (code 1).
-    if message.get_message_code() == 0 {
+    if message.get_init_code() == 0 {
         handle_pierce_firewall(
             message, stream, reader, &context, &peer_ip, peer_port,
         );

soulseek-rs-lib/src/peer/mod.rs

@@ -191,7 +191,7 @@ fn test_new_from_message2() {
     let mut message = Message::new_with_data(data);
     message.set_pointer(8);
 
-    println!("code: {}", message.get_message_code_u32());
+    println!("code: {}", message.get_message_code());
 
     let peer = Peer::new_from_message(&mut message).unwrap();
 

soulseek-rs-lib/tests/e2e.rs

@@ -750,7 +750,7 @@ fn login_raw(
 /// passes. Returns the matching message.
 fn read_until_code(
     stream: &mut TcpStream,
-    code: u8,
+    code: u32,
     timeout: Duration,
 ) -> Option<Message> {
     let deadline = Instant::now() + timeout;
@@ -767,7 +767,7 @@ fn read_until_code(
 /// Like [`read_until_code`] but turns a miss into an `io::Error` for `?`.
 fn expect_code(
     stream: &mut TcpStream,
-    code: u8,
+    code: u32,
     timeout: Duration,
 ) -> std::io::Result<Message> {
     read_until_code(stream, code, timeout).ok_or_else(|| {
@@ -1379,7 +1379,7 @@ fn run_mock_direct_peer(cfg: &MockDirectUpload) -> std::io::Result<()> {
     p.set_nonblocking(false)?;
     p.set_read_timeout(Some(Duration::from_secs(10)))?;
     let mut init = read_framed(&mut p)?;
-    assert_eq!(init.get_message_code(), 1, "expected inbound PeerInit");
+    assert_eq!(init.get_init_code(), 1, "expected inbound PeerInit");
     init.set_pointer(5);
     assert_eq!(init.read_string(), cfg.downloader_username, "PeerInit user");
     assert_eq!(init.read_string(), "P", "PeerInit connection type");
@@ -2079,7 +2079,7 @@ fn a_third_party_client_browses_our_shares_via_the_server_broker() {
 
     let mut pierce = read_framed(&mut p).expect("a PierceFirewall frame");
     assert_eq!(
-        pierce.get_message_code(),
+        pierce.get_init_code(),
         0,
         "the brokered connect-back must start with a PierceFirewall"
     );