Make librespot_playback work

playback/src/audio_backend/mod.rs

@@ -10,7 +10,9 @@ pub trait Sink {
     fn write(&mut self, data: &[i16]) -> io::Result<()>;
 }
 
-fn mk_sink<S: Sink + Open + 'static>(device: Option<String>) -> Box<dyn Sink> {
+pub type SinkBuilder = fn(Option<String>) -> Box<dyn Sink + Send>;
+
+fn mk_sink<S: Sink + Open + Send + 'static>(device: Option<String>) -> Box<dyn Sink + Send> {
     Box::new(S::open(device))
 }
 
@@ -54,7 +56,7 @@ use self::pipe::StdoutSink;
 mod subprocess;
 use self::subprocess::SubprocessSink;
 
-pub const BACKENDS: &'static [(&'static str, fn(Option<String>) -> Box<dyn Sink>)] = &[
+pub const BACKENDS: &'static [(&'static str, SinkBuilder)] = &[
     #[cfg(feature = "alsa-backend")]
     ("alsa", mk_sink::<AlsaSink>),
     #[cfg(feature = "portaudio-backend")]
@@ -73,7 +75,7 @@ pub const BACKENDS: &'static [(&'static str, fn(Option<String>) -> Box<dyn Sink>
     ("subprocess", mk_sink::<SubprocessSink>),
 ];
 
-pub fn find(name: Option<String>) -> Option<fn(Option<String>) -> Box<dyn Sink>> {
+pub fn find(name: Option<String>) -> Option<SinkBuilder> {
     if let Some(name) = name {
         BACKENDS
             .iter()

playback/src/audio_backend/pipe.rs

@@ -4,7 +4,7 @@ use std::io::{self, Write};
 use std::mem;
 use std::slice;
 
-pub struct StdoutSink(Box<dyn Write>);
+pub struct StdoutSink(Box<dyn Write + Send>);
 
 impl Open for StdoutSink {
     fn open(path: Option<String>) -> StdoutSink {

playback/src/player.rs

@@ -6,6 +6,7 @@ use crate::audio::{
 };
 use crate::audio_backend::Sink;
 use crate::config::{Bitrate, PlayerConfig};
+use crate::librespot_core::tokio;
 use crate::metadata::{AudioItem, FileFormat};
 use crate::mixer::AudioFilter;
 use librespot_core::session::Session;
@@ -19,7 +20,6 @@ use futures::{
 };
 use std::io::{Read, Seek, SeekFrom};
 use std::mem;
-use std::thread;
 use std::time::{Duration, Instant};
 use std::{borrow::Cow, io};
 use std::{
@@ -32,7 +32,7 @@ const PRELOAD_NEXT_TRACK_BEFORE_END_DURATION_MS: u32 = 30000;
 
 pub struct Player {
     commands: Option<mpsc::UnboundedSender<PlayerCommand>>,
-    thread_handle: Option<thread::JoinHandle<()>>,
+    task_handle: Option<tokio::task::JoinHandle<()>>,
     play_request_id_generator: SeqGenerator<u64>,
 }
 
@@ -52,7 +52,7 @@ struct PlayerInternal {
 
     state: PlayerState,
     preload: PlayerPreload,
-    sink: Box<dyn Sink>,
+    sink: Box<dyn Sink + Send>,
     sink_status: SinkStatus,
     sink_event_callback: Option<SinkEventCallback>,
     audio_filter: Option<Box<dyn AudioFilter + Send>>,
@@ -242,12 +242,11 @@ impl Player {
         sink_builder: F,
     ) -> (Player, PlayerEventChannel)
     where
-        F: FnOnce() -> Box<dyn Sink> + Send + 'static,
+        F: FnOnce() -> Box<dyn Sink + Send> + Send + 'static,
     {
         let (cmd_tx, cmd_rx) = mpsc::unbounded();
         let (event_sender, event_receiver) = mpsc::unbounded();
 
-        let handle = thread::spawn(move || {
         debug!("new Player[{}]", session.session_id());
 
         let internal = PlayerInternal {
@@ -266,14 +265,15 @@ impl Player {
 
         // While PlayerInternal is written as a future, it still contains blocking code.
         // It must be run by using wait() in a dedicated thread.
-            todo!("How to block in futures 0.3?");
+        let handle = tokio::spawn(async move {
+            internal.await;
             debug!("PlayerInternal thread finished.");
         });
 
         (
             Player {
                 commands: Some(cmd_tx),
-                thread_handle: Some(handle),
+                task_handle: Some(handle),
                 play_request_id_generator: SeqGenerator::new(0),
             },
             event_receiver,
@@ -347,11 +347,13 @@ impl Drop for Player {
     fn drop(&mut self) {
         debug!("Shutting down player thread ...");
         self.commands = None;
-        if let Some(handle) = self.thread_handle.take() {
-            match handle.join() {
+        if let Some(handle) = self.task_handle.take() {
+            tokio::spawn(async {
+                match handle.await {
                     Ok(_) => (),
                     Err(_) => error!("Player thread panicked!"),
                 }
+            });
         }
     }
 }
@@ -369,11 +371,11 @@ enum PlayerPreload {
     None,
     Loading {
         track_id: SpotifyId,
-        loader: Pin<Box<dyn Future<Output = Result<PlayerLoadedTrackData, ()>>>>,
+        loader: Pin<Box<dyn Future<Output = Result<PlayerLoadedTrackData, ()>> + Send>>,
     },
     Ready {
         track_id: SpotifyId,
-        loaded_track: PlayerLoadedTrackData,
+        loaded_track: Box<PlayerLoadedTrackData>,
     },
 }
 
@@ -385,7 +387,7 @@ enum PlayerState {
         track_id: SpotifyId,
         play_request_id: u64,
         start_playback: bool,
-        loader: Pin<Box<dyn Future<Output = Result<PlayerLoadedTrackData, ()>>>>,
+        loader: Pin<Box<dyn Future<Output = Result<PlayerLoadedTrackData, ()>> + Send>>,
     },
     Paused {
         track_id: SpotifyId,
@@ -430,23 +432,15 @@ impl PlayerState {
 
     #[allow(dead_code)]
     fn is_stopped(&self) -> bool {
-        use self::PlayerState::*;
-        match *self {
-            Stopped => true,
-            _ => false,
-        }
+        matches!(self, Self::Stopped)
     }
 
     fn is_loading(&self) -> bool {
-        use self::PlayerState::*;
-        match *self {
-            Loading { .. } => true,
-            _ => false,
-        }
+        matches!(self, Self::Loading { .. })
     }
 
     fn decoder(&mut self) -> Option<&mut Decoder> {
-        use self::PlayerState::*;
+        use PlayerState::*;
         match *self {
             Stopped | EndOfTrack { .. } | Loading { .. } => None,
             Paused {
@@ -575,10 +569,10 @@ struct PlayerTrackLoader {
 }
 
 impl PlayerTrackLoader {
-    async fn find_available_alternative<'a>(
-        &self,
-        audio: &'a AudioItem,
-    ) -> Option<Cow<'a, AudioItem>> {
+    async fn find_available_alternative<'a, 'b>(
+        &'a self,
+        audio: &'b AudioItem,
+    ) -> Option<Cow<'b, AudioItem>> {
         if audio.available {
             Some(Cow::Borrowed(audio))
         } else if let Some(alternatives) = &audio.alternatives {
@@ -716,7 +710,7 @@ impl PlayerTrackLoader {
             }
             Err(_) => {
                 warn!("Unable to extract normalisation data, using default value.");
-                1.0 as f32
+                1.0_f32
             }
         };
 
@@ -811,7 +805,7 @@ impl Future for PlayerInternal {
                         self.send_event(PlayerEvent::Preloading { track_id });
                         self.preload = PlayerPreload::Ready {
                             track_id,
-                            loaded_track,
+                            loaded_track: Box::new(loaded_track),
                         };
                     }
                     Poll::Ready(Err(_)) => {
@@ -1061,7 +1055,7 @@ impl PlayerInternal {
     fn handle_packet(&mut self, packet: Option<VorbisPacket>, normalisation_factor: f32) {
         match packet {
             Some(mut packet) => {
-                if packet.data().len() > 0 {
+                if !packet.data().is_empty() {
                     if let Some(ref editor) = self.audio_filter {
                         editor.modify_stream(&mut packet.data_mut())
                     };
@@ -1216,10 +1210,9 @@ impl PlayerInternal {
                     loaded_track
                         .stream_loader_controller
                         .set_random_access_mode();
-                    let _ = loaded_track.decoder.seek(position_ms as i64); // This may be blocking.
-                                                                           // But most likely the track is fully
-                                                                           // loaded already because we played
-                                                                           // to the end of it.
+                    let _ = tokio::task::block_in_place(|| {
+                        loaded_track.decoder.seek(position_ms as i64)
+                    });
                     loaded_track.stream_loader_controller.set_stream_mode();
                     loaded_track.stream_position_pcm = Self::position_ms_to_pcm(position_ms);
                 }
@@ -1252,7 +1245,7 @@ impl PlayerInternal {
                 // we can use the current decoder. Ensure it's at the correct position.
                 if Self::position_ms_to_pcm(position_ms) != *stream_position_pcm {
                     stream_loader_controller.set_random_access_mode();
-                    let _ = decoder.seek(position_ms as i64); // This may be blocking.
+                    let _ = tokio::task::block_in_place(|| decoder.seek(position_ms as i64));
                     stream_loader_controller.set_stream_mode();
                     *stream_position_pcm = Self::position_ms_to_pcm(position_ms);
                 }
@@ -1320,10 +1313,12 @@ impl PlayerInternal {
                         loaded_track
                             .stream_loader_controller
                             .set_random_access_mode();
-                        let _ = loaded_track.decoder.seek(position_ms as i64); // This may be blocking
+                        let _ = tokio::task::block_in_place(|| {
+                            loaded_track.decoder.seek(position_ms as i64)
+                        });
                         loaded_track.stream_loader_controller.set_stream_mode();
                     }
-                    self.start_playback(track_id, play_request_id, loaded_track, play);
+                    self.start_playback(track_id, play_request_id, *loaded_track, play);
                     return;
                 } else {
                     unreachable!();
@@ -1539,7 +1534,7 @@ impl PlayerInternal {
         &self,
         spotify_id: SpotifyId,
         position_ms: u32,
-    ) -> impl Future<Output = Result<PlayerLoadedTrackData, ()>> + 'static {
+    ) -> impl Future<Output = Result<PlayerLoadedTrackData, ()>> + Send + 'static {
         // This method creates a future that returns the loaded stream and associated info.
         // Ideally all work should be done using asynchronous code. However, seek() on the
         // audio stream is implemented in a blocking fashion. Thus, we can't turn it into future
@@ -1554,11 +1549,10 @@ impl PlayerInternal {
 
             let (result_tx, result_rx) = oneshot::channel();
 
-            std::thread::spawn(move || {
-                todo!("How to block in futures 0.3?")
-                /*if let Some(data) = block_on(loader.load_track(spotify_id, position_ms)) {
+            tokio::spawn(async move {
+                if let Some(data) = loader.load_track(spotify_id, position_ms).await {
                     let _ = result_tx.send(data);
-                }*/
+                }
             });
 
             result_rx.await.map_err(|_| ())
@@ -1588,7 +1582,9 @@ impl PlayerInternal {
                     * bytes_per_second as f64) as usize,
                 (READ_AHEAD_BEFORE_PLAYBACK_SECONDS * bytes_per_second as f64) as usize,
             );
-            stream_loader_controller.fetch_next_blocking(wait_for_data_length);
+            tokio::task::block_in_place(|| {
+                stream_loader_controller.fetch_next_blocking(wait_for_data_length)
+            });
         }
     }
 }

src/lib.rs

@@ -2,7 +2,7 @@
 #![cfg_attr(feature = "cargo-clippy", allow(unused_io_amount))]
 
 pub extern crate librespot_audio as audio;
-pub extern crate librespot_connect as connect;
+// pub extern crate librespot_connect as connect;
 pub extern crate librespot_core as core;
 pub extern crate librespot_metadata as metadata;
 pub extern crate librespot_playback as playback;