🚀 refactor(pmocontrol): eliminate QueueBackend boilerplate with HasQueue blanket impl

- Add `Hasqueue` trait and implement it for all renderers (Upnp, OpenHome, LinkPlay, ArylicTcp, Chromecast)
- Replace manual `QueueBackend` implementations with blanket impl for types implementing Hasqueue
  (removes ~30+ duplicated methods across renderers)
- Fix BUG: `sync_queue` in UpnpRenderer now correctly propagates cancel_token instead of ignoring it
- Update version to 0.3.48 in Cargo.toml, lockfile and root file
- Add refactoring plan document (`refactoring_pmocontrol.md`) detailing remaining P1-P3 tasks

pmocontrol/src/music_renderer/arylic_tcp.rs

@@ -18,8 +18,7 @@ use crate::music_renderer::capabilities::{
 use crate::music_renderer::musicrenderer::MusicRendererBackend;
 use crate::music_renderer::time_utils::{format_hhmmss, ms_to_seconds, parse_hhmmss_strict};
 use crate::music_renderer::RendererFromMediaRendererInfo;
-use crate::queue::MusicQueue;
-use crate::queue::{EnqueueMode, PlaybackItem, QueueBackend, QueueSnapshot};
+use crate::queue::{EnqueueMode, HasQueue, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
 use crate::DeviceIdentity;
 
 /// Raw response from Arylic MCU+PINFGET command
@@ -365,76 +364,9 @@ impl QueueTransportControl for ArylicTcpRenderer {
     }
 }
 
-impl QueueBackend for ArylicTcpRenderer {
-    fn len(&self) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().len()
-    }
-
-    fn track_ids(&self) -> Result<Vec<u32>, ControlPointError> {
-        self.queue.lock().unwrap().track_ids()
-    }
-
-    fn id_to_position(&self, id: u32) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().id_to_position(id)
-    }
-
-    fn position_to_id(&self, id: usize) -> Result<u32, ControlPointError> {
-        self.queue.lock().unwrap().position_to_id(id)
-    }
-
-    fn current_track(&self) -> Result<Option<u32>, ControlPointError> {
-        self.queue.lock().unwrap().current_track()
-    }
-
-    fn current_index(&self) -> Result<Option<usize>, ControlPointError> {
-        self.queue.lock().unwrap().current_index()
-    }
-
-    fn queue_snapshot(&self) -> Result<QueueSnapshot, ControlPointError> {
-        self.queue.lock().unwrap().queue_snapshot()
-    }
-
-    fn set_index(&mut self, index: Option<usize>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().set_index(index)
-    }
-
-    fn replace_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        current_index: Option<usize>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .replace_queue(items, current_index)
-    }
-
-    fn sync_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        _cancel_token: &Arc<AtomicBool>,
-        on_ready: Option<Box<dyn FnOnce() + Send>>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
-    }
-
-    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
-        self.queue.lock().unwrap().get_item(index)
-    }
-
-    fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().replace_item(index, item)
-    }
-
-    fn enqueue_items(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        mode: EnqueueMode,
-    ) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().enqueue_items(items, mode)
+impl HasQueue for ArylicTcpRenderer {
+    fn queue(&self) -> &Arc<Mutex<MusicQueue>> {
+        &self.queue
     }
 }
 

pmocontrol/src/music_renderer/capabilities.rs

@@ -1,9 +1,13 @@
 // pmocontrol/src/capabilities.rs
-use anyhow::Result;
 use std::sync::{Arc, Mutex};
 
-use crate::queue::MusicQueue;
-use crate::{errors::ControlPointError, model::PlaybackState};
+use crate::queue::{HasQueue, MusicQueue};
+use crate::{errors::ControlPointError, model::PlaybackState, PlaybackItem};
+
+/// Trait for types that track whether they're playing a continuous stream.
+pub trait HasContinuousStream {
+    fn continuous_stream(&self) -> &Arc<Mutex<bool>>;
+}
 
 /// Backend-specific operations for renderers.
 ///
@@ -18,7 +22,39 @@ pub trait RendererBackend {
 /// These operations combine queue management with transport control,
 /// allowing navigation (next/previous) and track selection from the queue.
 #[allow(dead_code)]
-pub trait QueueTransportControl {
+pub trait QueueTransportControl: HasQueue + HasContinuousStream {
+    /// Play a specific item from the queue (backend-specific implementation).
+    fn play_item(&self, item: &PlaybackItem) -> Result<(), ControlPointError>;
+
+    /// Play from the queue at the current index (or initialize to 0 if not set).
+    /// This is the default implementation that handles queue navigation.
+    fn play_from_queue(&self) -> Result<(), ControlPointError> {
+        let mut queue = self.queue().lock().unwrap();
+
+        let current_index = match queue.current_index()? {
+            Some(idx) => idx,
+            None => {
+                if queue.len()? > 0 {
+                    queue.set_index(Some(0))?;
+                    0
+                } else {
+                    return Err(ControlPointError::QueueError("Queue is empty".into()));
+                }
+            }
+        };
+
+        let item = queue
+            .get_item(current_index)?
+            .ok_or_else(|| ControlPointError::QueueError("Current item not found".into()))?;
+
+        drop(queue);
+
+        let is_stream = crate::music_renderer::is_continuous_stream_url(&item.uri);
+        *self.continuous_stream().lock().unwrap() = is_stream;
+
+        self.play_item(&item)
+    }
+
     /// Play the next track from the queue.
     fn play_next(&self) -> Result<(), ControlPointError>;
 
@@ -26,9 +62,6 @@ pub trait QueueTransportControl {
     #[allow(dead_code)]
     fn play_previous(&self) -> Result<(), ControlPointError>;
 
-    /// Play from the queue at the current index (or initialize to 0 if not set).
-    fn play_from_queue(&self) -> Result<(), ControlPointError>;
-
     /// Play from a specific index in the queue.
     fn play_from_index(&self, index: usize) -> Result<(), ControlPointError>;
 }

pmocontrol/src/music_renderer/chromecast_renderer.rs

@@ -29,7 +29,7 @@ use crate::music_renderer::capabilities::{
 use crate::music_renderer::musicrenderer::MusicRendererBackend;
 use crate::music_renderer::time_utils::{format_hhmmss_f64, parse_hhmmss_strict};
 use crate::music_renderer::RendererFromMediaRendererInfo;
-use crate::queue::{EnqueueMode, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
+use crate::queue::{EnqueueMode, HasQueue, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
 use crate::DeviceIdentity;
 
 use rust_cast::{
@@ -863,75 +863,8 @@ impl QueueTransportControl for ChromecastRenderer {
     }
 }
 
-impl QueueBackend for ChromecastRenderer {
-    fn len(&self) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().len()
-    }
-
-    fn track_ids(&self) -> Result<Vec<u32>, ControlPointError> {
-        self.queue.lock().unwrap().track_ids()
-    }
-
-    fn id_to_position(&self, id: u32) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().id_to_position(id)
-    }
-
-    fn position_to_id(&self, id: usize) -> Result<u32, ControlPointError> {
-        self.queue.lock().unwrap().position_to_id(id)
-    }
-
-    fn current_track(&self) -> Result<Option<u32>, ControlPointError> {
-        self.queue.lock().unwrap().current_track()
-    }
-
-    fn current_index(&self) -> Result<Option<usize>, ControlPointError> {
-        self.queue.lock().unwrap().current_index()
-    }
-
-    fn queue_snapshot(&self) -> Result<QueueSnapshot, ControlPointError> {
-        self.queue.lock().unwrap().queue_snapshot()
-    }
-
-    fn set_index(&mut self, index: Option<usize>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().set_index(index)
-    }
-
-    fn replace_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        current_index: Option<usize>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .replace_queue(items, current_index)
-    }
-
-    fn sync_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        _cancel_token: &Arc<AtomicBool>,
-        on_ready: Option<Box<dyn FnOnce() + Send>>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
-    }
-
-    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
-        self.queue.lock().unwrap().get_item(index)
-    }
-
-    fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().replace_item(index, item)
-    }
-
-    fn enqueue_items(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        mode: EnqueueMode,
-    ) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().enqueue_items(items, mode)
+impl HasQueue for ChromecastRenderer {
+    fn queue(&self) -> &Arc<Mutex<MusicQueue>> {
+        &self.queue
     }
 }

pmocontrol/src/music_renderer/linkplay_renderer.rs

@@ -16,8 +16,7 @@ use crate::music_renderer::capabilities::{
 use crate::music_renderer::musicrenderer::MusicRendererBackend;
 use crate::music_renderer::time_utils::parse_hhmmss_strict;
 use crate::music_renderer::RendererFromMediaRendererInfo;
-use crate::queue::MusicQueue;
-use crate::queue::{EnqueueMode, PlaybackItem, QueueBackend, QueueSnapshot};
+use crate::queue::{EnqueueMode, HasQueue, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
 use crate::DeviceIdentity;
 
 const DEFAULT_HTTP_TIMEOUT_SECS: u64 = 3;
@@ -243,75 +242,8 @@ impl QueueTransportControl for LinkPlayRenderer {
     }
 }
 
-impl QueueBackend for LinkPlayRenderer {
-    fn len(&self) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().len()
-    }
-
-    fn track_ids(&self) -> Result<Vec<u32>, ControlPointError> {
-        self.queue.lock().unwrap().track_ids()
-    }
-
-    fn id_to_position(&self, id: u32) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().id_to_position(id)
-    }
-
-    fn position_to_id(&self, id: usize) -> Result<u32, ControlPointError> {
-        self.queue.lock().unwrap().position_to_id(id)
-    }
-
-    fn current_track(&self) -> Result<Option<u32>, ControlPointError> {
-        self.queue.lock().unwrap().current_track()
-    }
-
-    fn current_index(&self) -> Result<Option<usize>, ControlPointError> {
-        self.queue.lock().unwrap().current_index()
-    }
-
-    fn queue_snapshot(&self) -> Result<QueueSnapshot, ControlPointError> {
-        self.queue.lock().unwrap().queue_snapshot()
-    }
-
-    fn set_index(&mut self, index: Option<usize>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().set_index(index)
-    }
-
-    fn replace_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        current_index: Option<usize>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .replace_queue(items, current_index)
-    }
-
-    fn sync_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        _cancel_token: &Arc<AtomicBool>,
-        on_ready: Option<Box<dyn FnOnce() + Send>>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
-    }
-
-    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
-        self.queue.lock().unwrap().get_item(index)
-    }
-
-    fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().replace_item(index, item)
-    }
-
-    fn enqueue_items(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        mode: EnqueueMode,
-    ) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().enqueue_items(items, mode)
+impl HasQueue for LinkPlayRenderer {
+    fn queue(&self) -> &Arc<Mutex<MusicQueue>> {
+        &self.queue
     }
 }

pmocontrol/src/music_renderer/openhome_renderer.rs

@@ -16,7 +16,7 @@ use crate::music_renderer::openhome::{
     build_time_client, build_volume_client,
 };
 use crate::music_renderer::RendererFromMediaRendererInfo;
-use crate::queue::{EnqueueMode, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
+use crate::queue::{EnqueueMode, HasQueue, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
 use crate::upnp_clients::{
     OhInfoClient, OhPlaylistClient, OhProductClient, OhRadioClient, OhTimeClient, OhVolumeClient,
     OPENHOME_PLAYLIST_HEAD_ID,
@@ -626,90 +626,31 @@ impl QueueTransportControl for OpenHomeRenderer {
     }
 }
 
-impl QueueBackend for OpenHomeRenderer {
-    fn len(&self) -> Result<usize, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .len()
+impl HasQueue for OpenHomeRenderer {
+    fn queue(&self) -> &Arc<Mutex<MusicQueue>> {
+        &self.queue
     }
+}
 
-    fn track_ids(&self) -> Result<Vec<u32>, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .track_ids()
-    }
-
-    fn id_to_position(&self, id: u32) -> Result<usize, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .id_to_position(id)
-    }
-
-    fn position_to_id(&self, id: usize) -> Result<u32, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .position_to_id(id)
-    }
-
-    fn current_track(&self) -> Result<Option<u32>, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .current_track()
-    }
-
-    fn current_index(&self) -> Result<Option<usize>, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .current_index()
-    }
-
-    fn queue_snapshot(&self) -> Result<QueueSnapshot, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .queue_snapshot()
-    }
-
-    fn set_index(&mut self, index: Option<usize>) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .set_index(index)
-    }
-
-    fn replace_queue(
+impl OpenHomeRenderer {
+    pub fn replace_queue_with_background(
         &mut self,
         items: Vec<PlaybackItem>,
         current_index: Option<usize>,
     ) -> Result<(), ControlPointError> {
-        // ✅ CORRECTION BUG PRODUCTION: On ne charge PAS toutes les métadonnées
-        // dans le thread principal. OpenHome sur 1000 titres inondait la base SQLite
-        // et bloquait TOUS les autres threads (mutex >500ms).
-        //
-        // On fait juste l'insertion minimaliste maintenant. Le préchargement
-        // des métadonnées est délégué à un thread background.
         self.queue
             .lock()
             .map_err(|_| ControlPointError::QueueError("Mutex poisoned".into()))?
             .replace_queue(items, current_index)?;
 
-        // Background worker: charge les métadonnées petit à petit sans bloquer personne
         let queue = self.queue.clone();
         std::thread::spawn(move || {
             debug!("🔄 OpenHome: préchargement métadonnées queue en background");
             if let Ok(mut queue) = queue.lock() {
-                // On ne fait que les 10 prochains titres maintenant, le reste on s'en fout
                 if let Ok(Some(idx)) = queue.current_index() {
                     let end = std::cmp::min(idx + 10, queue.len().unwrap_or(0));
                     for i in idx..end {
                         let _ = queue.get_item(i);
-                        // Petit délai pour ne pas noyer la base de données
                         std::thread::sleep(std::time::Duration::from_millis(5));
                     }
                 }
@@ -719,41 +660,4 @@ impl QueueBackend for OpenHomeRenderer {
 
         Ok(())
     }
-
-    fn sync_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        cancel_token: &Arc<AtomicBool>,
-        on_ready: Option<Box<dyn FnOnce() + Send>>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .sync_queue(items, cancel_token, on_ready)
-    }
-
-    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .get_item(index)
-    }
-
-    fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .replace_item(index, item)
-    }
-
-    fn enqueue_items(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        mode: EnqueueMode,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .enqueue_items(items, mode)
-    }
 }

pmocontrol/src/music_renderer/upnp_renderer.rs

@@ -3,12 +3,12 @@ use std::sync::{atomic::AtomicBool, Arc, Mutex};
 use crate::errors::ControlPointError;
 use crate::model::PlaybackState;
 use crate::music_renderer::capabilities::{
-    PlaybackPosition, PlaybackPositionInfo, PlaybackStatus, QueueTransportControl, RendererBackend,
-    TransportControl, VolumeControl,
+    HasContinuousStream, PlaybackPosition, PlaybackPositionInfo, PlaybackStatus,
+    QueueTransportControl, RendererBackend, TransportControl, VolumeControl,
 };
 use crate::music_renderer::musicrenderer::{build_didl_lite_metadata, MusicRendererBackend};
 use crate::music_renderer::RendererFromMediaRendererInfo;
-use crate::queue::{EnqueueMode, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
+use crate::queue::{EnqueueMode, HasQueue, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
 use crate::upnp_clients::{
     AvTransportClient, ConnectionInfo, ConnectionManagerClient, PositionInfo, ProtocolInfo,
     RenderingControlClient,
@@ -307,76 +307,9 @@ impl QueueTransportControl for UpnpRenderer {
     }
 }
 
-impl QueueBackend for UpnpRenderer {
-    fn len(&self) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().len()
-    }
-
-    fn track_ids(&self) -> Result<Vec<u32>, ControlPointError> {
-        self.queue.lock().unwrap().track_ids()
-    }
-
-    fn id_to_position(&self, id: u32) -> Result<usize, ControlPointError> {
-        self.queue.lock().unwrap().id_to_position(id)
-    }
-
-    fn position_to_id(&self, id: usize) -> Result<u32, ControlPointError> {
-        self.queue.lock().unwrap().position_to_id(id)
-    }
-
-    fn current_track(&self) -> Result<Option<u32>, ControlPointError> {
-        self.queue.lock().unwrap().current_track()
-    }
-
-    fn current_index(&self) -> Result<Option<usize>, ControlPointError> {
-        self.queue.lock().unwrap().current_index()
-    }
-
-    fn queue_snapshot(&self) -> Result<QueueSnapshot, ControlPointError> {
-        self.queue.lock().unwrap().queue_snapshot()
-    }
-
-    fn set_index(&mut self, index: Option<usize>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().set_index(index)
-    }
-
-    fn replace_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        current_index: Option<usize>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .replace_queue(items, current_index)
-    }
-
-    fn sync_queue(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        _cancel_token: &Arc<AtomicBool>,
-        on_ready: Option<Box<dyn FnOnce() + Send>>,
-    ) -> Result<(), ControlPointError> {
-        self.queue
-            .lock()
-            .unwrap()
-            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
-    }
-
-    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
-        self.queue.lock().unwrap().get_item(index)
-    }
-
-    fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().replace_item(index, item)
-    }
-
-    fn enqueue_items(
-        &mut self,
-        items: Vec<PlaybackItem>,
-        mode: EnqueueMode,
-    ) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().enqueue_items(items, mode)
+impl HasQueue for UpnpRenderer {
+    fn queue(&self) -> &Arc<Mutex<MusicQueue>> {
+        &self.queue
     }
 }
 

pmocontrol/src/queue/backend.rs

@@ -28,8 +28,89 @@
 //!   - This identity is used by the sync helpers to preserve the current
 //!     track across queue rebuilds when the MediaServer content changes.
 
+use crate::queue::MusicQueue;
 use crate::{errors::ControlPointError, PlaybackItem, QueueSnapshot};
-use std::sync::{atomic::AtomicBool, Arc};
+use std::sync::{atomic::AtomicBool, Arc, Mutex};
+
+/// Trait for types that have aMusicQueue.
+pub trait HasQueue {
+    fn queue(&self) -> &Arc<Mutex<MusicQueue>>;
+}
+
+/// Blanket implementation of QueueBackend for types that have a queue.
+/// All methods simply delegate to the underlying MusicQueue.
+impl<T: HasQueue> QueueBackend for T {
+    fn len(&self) -> Result<usize, ControlPointError> {
+        self.queue().lock().unwrap().len()
+    }
+
+    fn track_ids(&self) -> Result<Vec<u32>, ControlPointError> {
+        self.queue().lock().unwrap().track_ids()
+    }
+
+    fn id_to_position(&self, id: u32) -> Result<usize, ControlPointError> {
+        self.queue().lock().unwrap().id_to_position(id)
+    }
+
+    fn position_to_id(&self, id: usize) -> Result<u32, ControlPointError> {
+        self.queue().lock().unwrap().position_to_id(id)
+    }
+
+    fn current_track(&self) -> Result<Option<u32>, ControlPointError> {
+        self.queue().lock().unwrap().current_track()
+    }
+
+    fn current_index(&self) -> Result<Option<usize>, ControlPointError> {
+        self.queue().lock().unwrap().current_index()
+    }
+
+    fn queue_snapshot(&self) -> Result<QueueSnapshot, ControlPointError> {
+        self.queue().lock().unwrap().queue_snapshot()
+    }
+
+    fn set_index(&mut self, index: Option<usize>) -> Result<(), ControlPointError> {
+        self.queue().lock().unwrap().set_index(index)
+    }
+
+    fn replace_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        current_index: Option<usize>,
+    ) -> Result<(), ControlPointError> {
+        self.queue()
+            .lock()
+            .unwrap()
+            .replace_queue(items, current_index)
+    }
+
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        self.queue()
+            .lock()
+            .unwrap()
+            .sync_queue(items, cancel_token, on_ready)
+    }
+
+    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
+        self.queue().lock().unwrap().get_item(index)
+    }
+
+    fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
+        self.queue().lock().unwrap().replace_item(index, item)
+    }
+
+    fn enqueue_items(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        mode: EnqueueMode,
+    ) -> Result<(), ControlPointError> {
+        self.queue().lock().unwrap().enqueue_items(items, mode)
+    }
+}
 
 /// High-level enqueue mode.
 ///

pmocontrol/src/queue/mod.rs

@@ -6,7 +6,7 @@ mod snapshot;
 
 use std::sync::{Arc, Mutex};
 
-pub use backend::{EnqueueMode, QueueBackend};
+pub use backend::{EnqueueMode, HasQueue, QueueBackend};
 pub use music_queue::{MusicQueue, SyncScheduleOutcome};
 pub use snapshot::{PlaybackItem, QueueSnapshot};