feat(lib): answer UserInfoRequest with our slots and queue

Opening a user's profile in SoulseekQt or Nicotine+ asks that peer
directly (peer code 15), and a peer that never answers shows an endless
spinner. The reply (code 16) carries no description or picture, the
configured upload slot count, how many uploads are waiting, and whether a
slot is free right now, which is what the reference clients send.

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

@@ -6,6 +6,7 @@ use crate::message::peer::{
     PlaceInQueueRequest, PlaceInQueueResponse, QueueUploadHandler,
     SharedDirectory, SharedFileListResponseHandler, TransferRequest,
     TransferResponse, UploadDeniedHandler, UploadFailedHandler,
+    UserInfoRequest,
 };
 use crate::message::server::MessageFactory;
 use crate::message::{Handlers, Message, MessageReader, MessageType};
@@ -46,6 +47,8 @@ pub enum PeerMessage {
     ShareListRequested,
     /// A peer we are browsing sent us their shared-file listing (code 5).
     ShareListReceived(Vec<SharedDirectory>),
+    /// A peer asked what we say about ourselves (they sent us code 15).
+    UserInfoRequested,
     /// A peer asked for one folder of our shares (they sent us code 36).
     FolderContentsRequested {
         token: u32,
@@ -184,6 +187,7 @@ impl PeerActor {
         handlers.register_handler(TransferResponse);
         handlers.register_handler(GetShareFileList);
         handlers.register_handler(FolderContentsRequest);
+        handlers.register_handler(UserInfoRequest);
         handlers.register_handler(UploadDeniedHandler);
         handlers.register_handler(UploadFailedHandler);
         handlers.register_handler(PlaceInQueueRequest);
@@ -274,13 +278,27 @@ impl PeerActor {
                 self.handle_serve_upload(token, filename, size);
             }
             PeerMessage::ShareListRequested => {
-                self.handle_share_list_requested();
+                self.forward(ClientOperation::ShareListRequested {
+                    requester_key: self.peer_username(),
+                });
             }
             PeerMessage::ShareListReceived(directories) => {
-                self.handle_share_list_received(directories);
+                self.forward(ClientOperation::BrowseResult {
+                    username: self.peer_username(),
+                    directories,
+                });
+            }
+            PeerMessage::UserInfoRequested => {
+                self.forward(ClientOperation::UserInfoRequested {
+                    requester_key: self.peer_username(),
+                });
             }
             PeerMessage::FolderContentsRequested { token, folder } => {
-                self.handle_folder_contents_requested(token, folder);
+                self.forward(ClientOperation::FolderContentsRequested {
+                    requester_key: self.peer_username(),
+                    token,
+                    folder,
+                });
             }
             PeerMessage::RequestTransfer(download) => {
                 let message = MessageFactory::build_transfer_request_message(
@@ -440,39 +458,9 @@ impl PeerActor {
         self.send_message(message);
     }
 
-    fn handle_share_list_requested(&self) {
-        let requester_key = self.peer_username();
-        if let Err(e) = self
-            .client_channel
-            .send(ClientOperation::ShareListRequested { requester_key })
-        {
-            error!("[peer_actor] forward ShareListRequested: {}", e);
-        }
-    }
-
-    fn handle_folder_contents_requested(&self, token: u32, folder: String) {
-        let requester_key = self.peer_username();
-        if let Err(e) =
-            self.client_channel
-                .send(ClientOperation::FolderContentsRequested {
-                    requester_key,
-                    token,
-                    folder,
-                })
-        {
-            error!("[peer_actor] forward FolderContentsRequested: {}", e);
-        }
-    }
-
-    fn handle_share_list_received(&self, directories: Vec<SharedDirectory>) {
-        let username = self.peer_username();
-        if let Err(e) =
-            self.client_channel.send(ClientOperation::BrowseResult {
-                username,
-                directories,
-            })
-        {
-            error!("[peer_actor] forward BrowseResult: {}", e);
+    fn forward(&self, operation: ClientOperation) {
+        if let Err(e) = self.client_channel.send(operation) {
+            error!("[peer_actor] forward to client: {}", e);
         }
     }
 

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

@@ -292,6 +292,10 @@ pub enum ClientOperation {
     ShareListRequested {
         requester_key: String,
     },
+    /// A peer asked what we say about ourselves; send a UserInfoResponse.
+    UserInfoRequested {
+        requester_key: String,
+    },
     /// A peer asked for one folder of our shares; send a FolderContentsResponse.
     FolderContentsRequested {
         requester_key: String,

soulseek-rs-lib/src/client/operations.rs

@@ -766,6 +766,19 @@ impl Client {
                             },
                         );
                     }
+                    ClientOperation::UserInfoRequested { requester_key } => {
+                        Self::reply_to_peer(
+                            &client_context,
+                            &requester_key,
+                            |ctx| {
+                                crate::message::peer::build_user_info(
+                                    ctx.upload_slots as u32,
+                                    ctx.upload_queue.len() as u32,
+                                    ctx.has_free_upload_slot(),
+                                )
+                            },
+                        );
+                    }
                     ClientOperation::FolderContentsRequested {
                         requester_key,
                         token,

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

@@ -10,6 +10,7 @@ mod transfer_request;
 mod transfer_response;
 mod upload_denied;
 mod upload_failed;
+mod user_info;
 
 // Re-export handlers
 pub use file_search_response::{
@@ -31,3 +32,4 @@ pub use transfer_request::TransferRequest;
 pub use transfer_response::TransferResponse;
 pub use upload_denied::UploadDeniedHandler;
 pub use upload_failed::UploadFailedHandler;
+pub use user_info::{UserInfoRequest, build_user_info};

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

@@ -0,0 +1,33 @@
+//! `UserInfoRequest` (peer code 15) and its reply (code 16): what a peer says
+//! about itself when another user opens its profile.
+
+use crate::message::{Message, MessageHandler};
+use crate::peer::PeerMessage;
+use std::sync::mpsc::Sender;
+
+pub struct UserInfoRequest;
+impl MessageHandler<PeerMessage> for UserInfoRequest {
+    fn get_code(&self) -> u32 {
+        15
+    }
+    fn handle(&self, _message: &mut Message, sender: Sender<PeerMessage>) {
+        let _ = sender.send(PeerMessage::UserInfoRequested);
+    }
+}
+
+/// Build a `UserInfoResponse` (peer code 16) with no description or picture.
+#[must_use]
+pub fn build_user_info(
+    upload_slots: u32,
+    queue_size: u32,
+    slots_free: bool,
+) -> Message {
+    Message::new()
+        .write_int32(16)
+        .write_string("")
+        .write_bool(false)
+        .write_int32(upload_slots)
+        .write_int32(queue_size)
+        .write_bool(slots_free)
+        .clone()
+}