Prepare for gapless play.

- change communication between player and spirc to use player events channel.
- enhance player events channel
- have spirc send loading messages to Spotify
- enable preloading of tracks in the player

audio/src/fetch.rs

@@ -144,6 +144,15 @@ impl StreamLoaderController {
         }
     }
 
+    pub fn range_to_end_available(&self) -> bool {
+        if let Some(ref shared) = self.stream_shared {
+            let read_position = shared.read_position.load(atomic::Ordering::Relaxed);
+            self.range_available(Range::new(read_position, self.len() - read_position))
+        } else {
+            true
+        }
+    }
+
     pub fn ping_time_ms(&self) -> usize {
         if let Some(ref shared) = self.stream_shared {
             return shared.ping_time_ms.load(atomic::Ordering::Relaxed);

connect/src/spirc.rs

@@ -2,7 +2,7 @@ use std;
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use futures::future;
-use futures::sync::{mpsc, oneshot};
+use futures::sync::mpsc;
 use futures::{Async, Future, Poll, Sink, Stream};
 use protobuf::{self, Message};
 use rand;
@@ -11,7 +11,7 @@ use serde_json;
 
 use crate::context::StationContext;
 use crate::playback::mixer::Mixer;
-use crate::playback::player::Player;
+use crate::playback::player::{Player, PlayerEvent, PlayerEventChannel};
 use crate::protocol;
 use crate::protocol::spirc::{DeviceState, Frame, MessageType, PlayStatus, State, TrackRef};
 use librespot_core::config::ConnectConfig;
@@ -22,6 +22,14 @@ use librespot_core::util::SeqGenerator;
 use librespot_core::version;
 use librespot_core::volume::Volume;
 
+enum SpircPlayStatus {
+    Stopped,
+    LoadingPlay { position_ms: u32 },
+    LoadingPause { position_ms: u32 },
+    Playing { nominal_start_time: i64 },
+    Paused { position_ms: u32 },
+}
+
 pub struct SpircTask {
     player: Player,
     mixer: Box<dyn Mixer>,
@@ -32,11 +40,14 @@ pub struct SpircTask {
     ident: String,
     device: DeviceState,
     state: State,
+    play_request_id: Option<u64>,
+    mixer_started: bool,
+    play_status: SpircPlayStatus,
 
     subscription: Box<dyn Stream<Item = Frame, Error = MercuryError>>,
     sender: Box<dyn Sink<SinkItem = Frame, SinkError = MercuryError>>,
     commands: mpsc::UnboundedReceiver<SpircCommand>,
-    end_of_track: Box<dyn Future<Item = (), Error = oneshot::Canceled>>,
+    player_events: PlayerEventChannel,
 
     shutdown: bool,
     session: Session,
@@ -255,6 +266,8 @@ impl Spirc {
         };
         let device = initial_device_state(config);
 
+        let player_events = player.get_player_event_channel();
+
         let mut task = SpircTask {
             player: player,
             mixer: mixer,
@@ -266,11 +279,14 @@ impl Spirc {
 
             device: device,
             state: initial_state(),
+            play_request_id: None,
+            mixer_started: false,
+            play_status: SpircPlayStatus::Stopped,
 
             subscription: subscription,
             sender: sender,
             commands: cmd_rx,
-            end_of_track: Box::new(future::empty()),
+            player_events: player_events,
 
             shutdown: false,
             session: session.clone(),
@@ -350,13 +366,14 @@ impl Future for SpircTask {
                     Async::NotReady => (),
                 }
 
-                match self.end_of_track.poll() {
-                    Ok(Async::Ready(())) => {
+                match self.player_events.poll() {
+                    Ok(Async::NotReady) => (),
+                    Ok(Async::Ready(None)) => (),
+                    Err(_) => (),
+                    Ok(Async::Ready(Some(event))) => {
                         progress = true;
-                        self.handle_end_of_track();
+                        self.handle_player_event(event);
                     }
-                    Ok(Async::NotReady) => (),
-                    Err(oneshot::Canceled) => self.end_of_track = Box::new(future::empty()),
                 }
                 // TODO: Refactor
                 match self.context_fut.poll() {
@@ -431,6 +448,26 @@ impl SpircTask {
             + (dur.subsec_nanos() / 1000_000) as i64)
     }
 
+    fn ensure_mixer_started(&mut self) {
+        if !self.mixer_started {
+            self.mixer.start();
+            self.mixer_started = true;
+        }
+    }
+
+    fn ensure_mixer_stopped(&mut self) {
+        if self.mixer_started {
+            self.mixer.stop();
+            self.mixer_started = false;
+        }
+    }
+
+    fn update_state_position(&mut self, position_ms: u32) {
+        let now = self.now_ms();
+        self.state.set_position_measured_at(now as u64);
+        self.state.set_position_ms(position_ms);
+    }
+
     fn handle_command(&mut self, cmd: SpircCommand) {
         let active = self.device.get_is_active();
         match cmd {
@@ -498,14 +535,112 @@ impl SpircTask {
         }
     }
 
+    fn handle_player_event(&mut self, event: PlayerEvent) {
+        // we only process events if the play_request_id matches. If it doesn't, it is
+        // an event that belongs to a previous track and only arrives now due to a race
+        // condition. In this case we have updated the state already and don't want to
+        // mess with it.
+        if let Some(play_request_id) = event.get_play_request_id() {
+            if Some(play_request_id) == self.play_request_id {
+                match event {
+                    PlayerEvent::EndOfTrack { .. } => self.handle_end_of_track(),
+                    PlayerEvent::Loading { .. } => (),
+                    PlayerEvent::Playing { position_ms, .. } => {
+                        let new_nominal_start_time =
+                            self.now_ms() - position_ms as i64;
+                        match self.play_status {
+                            SpircPlayStatus::Playing { nominal_start_time } => {
+                                if (nominal_start_time - new_nominal_start_time)
+                                    .abs()
+                                    > 100
+                                {
+                                    self.update_state_position(position_ms);
+                                    self.notify(None);
+                                    self.play_status = SpircPlayStatus::Playing {
+                                        nominal_start_time: new_nominal_start_time,
+                                    };
+                                }
+                            }
+                            SpircPlayStatus::LoadingPlay { .. }
+                            | SpircPlayStatus::LoadingPause { .. } => {
+                                self.state.set_status(PlayStatus::kPlayStatusPlay);
+                                self.update_state_position(position_ms);
+                                self.notify(None);
+                                self.play_status = SpircPlayStatus::Playing {
+                                    nominal_start_time: new_nominal_start_time,
+                                };
+                            }
+                            _ => (),
+                        };
+                        trace!("==> kPlayStatusPlay");
+                    }
+                    PlayerEvent::Paused {
+                        position_ms: new_position_ms,
+                        ..
+                    } => {
+                        match self.play_status {
+                            SpircPlayStatus::Paused {
+                                ref mut position_ms,
+                            } => {
+                                if *position_ms != new_position_ms {
+                                    *position_ms = new_position_ms;
+                                    self.update_state_position(new_position_ms);
+                                    self.notify(None);
+                                }
+                            }
+                            SpircPlayStatus::LoadingPlay { .. }
+                            | SpircPlayStatus::LoadingPause { .. } => {
+                                self.state.set_status(PlayStatus::kPlayStatusPause);
+                                self.update_state_position(new_position_ms);
+                                self.notify(None);
+                                self.play_status = SpircPlayStatus::Paused {
+                                    position_ms: new_position_ms,
+                                };
+                            }
+                            _ => (),
+                        }
+                        trace!("==> kPlayStatusPause");
+                    }
+                    PlayerEvent::Stopped { .. } => match self.play_status {
+                        SpircPlayStatus::Stopped => (),
+                        _ => {
+                            warn!("The player has stopped unexpentedly.");
+                            self.state.set_status(PlayStatus::kPlayStatusStop);
+                            self.ensure_mixer_stopped();
+                            self.notify(None);
+                            self.play_status = SpircPlayStatus::Stopped;
+                        }
+                    },
+                    PlayerEvent::TimeToPreloadNextTrack {..} => match self.play_status {
+                        SpircPlayStatus::Paused {..}|SpircPlayStatus::Playing {..}| SpircPlayStatus::LoadingPause{..}|SpircPlayStatus::LoadingPlay {..} => {
+                            if let Some(track_id) = self.preview_next_track() {
+                                self.player.preload(track_id);
+                            }
+                        }
+                        SpircPlayStatus::Stopped => (),
+                    }
+                    _ => (),
+                }
+            }
+        }
+    }
+
     fn handle_frame(&mut self, frame: Frame) {
+        let state_string = match frame.get_state().get_status() {
+            PlayStatus::kPlayStatusLoading => "kPlayStatusLoading",
+            PlayStatus::kPlayStatusPause => "kPlayStatusPause",
+            PlayStatus::kPlayStatusStop => "kPlayStatusStop",
+            PlayStatus::kPlayStatusPlay => "kPlayStatusPlay",
+        };
+
         debug!(
-            "{:?} {:?} {} {} {}",
+            "{:?} {:?} {} {} {} {}",
             frame.get_typ(),
             frame.get_device_state().get_name(),
             frame.get_ident(),
             frame.get_seq_nr(),
-            frame.get_state_update_id()
+            frame.get_state_update_id(),
+            state_string,
         );
 
         if frame.get_ident() == self.ident
@@ -529,18 +664,15 @@ impl SpircTask {
                 self.update_tracks(&frame);
 
                 if self.state.get_track().len() > 0 {
-                    let now = self.now_ms();
-                    self.state
-                        .set_position_ms(frame.get_state().get_position_ms());
-                    self.state.set_position_measured_at(now as u64);
-
-                    let play = frame.get_state().get_status() == PlayStatus::kPlayStatusPlay;
-                    self.load_track(play);
+                    let start_playing =
+                        frame.get_state().get_status() == PlayStatus::kPlayStatusPlay;
+                    self.load_track(start_playing, frame.get_state().get_position_ms());
                 } else {
                     info!("No more tracks left in queue");
                     self.state.set_status(PlayStatus::kPlayStatusStop);
                     self.player.stop();
                     self.mixer.stop();
+                    self.play_status = SpircPlayStatus::Stopped;
                 }
 
                 self.notify(None);
@@ -607,12 +739,7 @@ impl SpircTask {
             }
 
             MessageType::kMessageTypeSeek => {
-                let position = frame.get_position();
-
-                let now = self.now_ms();
-                self.state.set_position_ms(position);
-                self.state.set_position_measured_at(now as u64);
-                self.player.seek(position);
+                self.handle_seek(frame.get_position());
                 self.notify(None);
             }
 
@@ -631,7 +758,8 @@ impl SpircTask {
                     self.device.set_is_active(false);
                     self.state.set_status(PlayStatus::kPlayStatusStop);
                     self.player.stop();
-                    self.mixer.stop();
+                    self.ensure_mixer_stopped();
+                    self.play_status = SpircPlayStatus::Stopped;
                 }
             }
 
@@ -640,39 +768,75 @@ impl SpircTask {
     }
 
     fn handle_play(&mut self) {
-        if self.state.get_status() == PlayStatus::kPlayStatusPause {
-            self.mixer.start();
-            self.player.play();
-            self.state.set_status(PlayStatus::kPlayStatusPlay);
-            let now = self.now_ms();
-            self.state.set_position_measured_at(now as u64);
+        match self.play_status {
+            SpircPlayStatus::Paused { position_ms } => {
+                self.ensure_mixer_started();
+                self.player.play();
+                self.state.set_status(PlayStatus::kPlayStatusPlay);
+                self.update_state_position(position_ms);
+                self.play_status = SpircPlayStatus::Playing {
+                    nominal_start_time: self.now_ms() as i64 - position_ms as i64,
+                };
+            }
+            SpircPlayStatus::LoadingPause { position_ms } => {
+                self.ensure_mixer_started();
+                self.player.play();
+                self.play_status = SpircPlayStatus::LoadingPlay { position_ms };
+            }
+            _ => (),
         }
     }
 
     fn handle_play_pause(&mut self) {
-        match self.state.get_status() {
-            PlayStatus::kPlayStatusPlay => self.handle_pause(),
-            PlayStatus::kPlayStatusPause => self.handle_play(),
+        match self.play_status {
+            SpircPlayStatus::Paused { .. } | SpircPlayStatus::LoadingPause { .. } => {
+                self.handle_play()
+            }
+            SpircPlayStatus::Playing { .. } | SpircPlayStatus::LoadingPlay { .. } => {
+                self.handle_play()
+            }
             _ => (),
         }
     }
 
     fn handle_pause(&mut self) {
-        if self.state.get_status() == PlayStatus::kPlayStatusPlay {
-            self.player.pause();
-            self.mixer.stop();
-            self.state.set_status(PlayStatus::kPlayStatusPause);
-
-            let now = self.now_ms() as u64;
-            let position = self.state.get_position_ms();
-
-            let diff = now - self.state.get_position_measured_at();
-
-            self.state.set_position_ms(position + diff as u32);
-            self.state.set_position_measured_at(now);
+        match self.play_status {
+            SpircPlayStatus::Playing { nominal_start_time } => {
+                self.player.pause();
+                self.state.set_status(PlayStatus::kPlayStatusPause);
+                let position_ms = (self.now_ms() - nominal_start_time) as u32;
+                self.update_state_position(position_ms);
+                self.play_status = SpircPlayStatus::Paused { position_ms };
+            }
+            SpircPlayStatus::LoadingPlay { position_ms } => {
+                self.player.pause();
+                self.play_status = SpircPlayStatus::LoadingPause { position_ms };
+            }
+            _ => (),
         }
     }
 
+    fn handle_seek(&mut self, position_ms: u32) {
+        self.update_state_position(position_ms);
+        self.player.seek(position_ms);
+        let now = self.now_ms();
+        match self.play_status {
+            SpircPlayStatus::Stopped => (),
+            SpircPlayStatus::LoadingPause {
+                position_ms: ref mut position,
+            }
+            | SpircPlayStatus::LoadingPlay {
+                position_ms: ref mut position,
+            }
+            | SpircPlayStatus::Paused {
+                position_ms: ref mut position,
+            } => *position = position_ms,
+            SpircPlayStatus::Playing {
+                ref mut nominal_start_time,
+            } => *nominal_start_time = now - position_ms as i64,
+        };
+    }
+
     fn consume_queued_track(&mut self) -> usize {
         // Removes current track if it is queued
         // Returns the index of the next track
@@ -687,6 +851,10 @@ impl SpircTask {
         }
     }
 
+    fn preview_next_track(&mut self) -> Option<SpotifyId> {
+        None
+    }
+
     fn handle_next(&mut self) {
         let mut new_index = self.consume_queued_track() as u32;
         let mut continue_playing = true;
@@ -720,17 +888,14 @@ impl SpircTask {
 
         if tracks_len > 0 {
             self.state.set_playing_track_index(new_index);
-            self.state.set_position_ms(0);
-            let now = self.now_ms();
-            self.state.set_position_measured_at(now as u64);
-
-            self.load_track(continue_playing);
+            self.load_track(continue_playing, 0);
         } else {
             info!("Not playing next track because there are no more tracks left in queue.");
             self.state.set_playing_track_index(0);
             self.state.set_status(PlayStatus::kPlayStatusStop);
             self.player.stop();
-            self.mixer.stop();
+            self.ensure_mixer_stopped();
+            self.play_status = SpircPlayStatus::Stopped;
         }
     }
 
@@ -765,17 +930,11 @@ impl SpircTask {
                 pos += 1;
             }
 
-            let now = self.now_ms();
             self.state.set_playing_track_index(new_index);
-            self.state.set_position_ms(0);
-            self.state.set_position_measured_at(now as u64);
 
-            self.load_track(true);
+            self.load_track(true, 0);
         } else {
-            let now = self.now_ms();
-            self.state.set_position_ms(0);
-            self.state.set_position_measured_at(now as u64);
-            self.player.seek(0);
+            self.handle_seek(0);
         }
     }
 
@@ -801,8 +960,15 @@ impl SpircTask {
     }
 
     fn position(&mut self) -> u32 {
-        let diff = self.now_ms() as u64 - self.state.get_position_measured_at();
-        self.state.get_position_ms() + diff as u32
+        match self.play_status {
+            SpircPlayStatus::Stopped => 0,
+            SpircPlayStatus::LoadingPlay { position_ms }
+            | SpircPlayStatus::LoadingPause { position_ms }
+            | SpircPlayStatus::Paused { position_ms } => position_ms,
+            SpircPlayStatus::Playing { nominal_start_time } => {
+                (self.now_ms() - nominal_start_time) as u32
+            }
+        }
     }
 
     fn resolve_station(
@@ -912,7 +1078,7 @@ impl SpircTask {
         })
     }
 
-    fn load_track(&mut self, play: bool) {
+    fn load_track(&mut self, start_playing: bool, position_ms: u32) {
         let context_uri = self.state.get_context_uri().to_owned();
         let mut index = self.state.get_playing_track_index();
         let start_index = index;
@@ -949,16 +1115,15 @@ impl SpircTask {
         }
         .expect("Invalid SpotifyId");
 
-        let position = self.state.get_position_ms();
-        let end_of_track = self.player.load(track, play, position);
+        self.play_request_id = Some(self.player.load(track, start_playing, position_ms));
 
-        if play {
-            self.state.set_status(PlayStatus::kPlayStatusPlay);
+        self.update_state_position(position_ms);
+        self.state.set_status(PlayStatus::kPlayStatusLoading);
+        if start_playing {
+            self.play_status = SpircPlayStatus::LoadingPlay { position_ms };
         } else {
-            self.state.set_status(PlayStatus::kPlayStatusPause);
+            self.play_status = SpircPlayStatus::LoadingPause { position_ms };
         }
-
-        self.end_of_track = Box::new(end_of_track);
     }
 
     fn hello(&mut self) {
@@ -966,6 +1131,13 @@ impl SpircTask {
     }
 
     fn notify(&mut self, recipient: Option<&str>) {
+        let status_string = match self.state.get_status() {
+            PlayStatus::kPlayStatusLoading => "kPlayStatusLoading",
+            PlayStatus::kPlayStatusPause => "kPlayStatusPause",
+            PlayStatus::kPlayStatusStop => "kPlayStatusStop",
+            PlayStatus::kPlayStatusPlay => "kPlayStatusPlay",
+        };
+        trace!("Sending status to server: [{}]", status_string);
         let mut cs = CommandSender::new(self, MessageType::kMessageTypeNotify);
         if let Some(s) = recipient {
             cs = cs.recipient(&s);
@@ -980,6 +1152,7 @@ impl SpircTask {
         if let Some(cache) = self.session.cache() {
             cache.save_volume(Volume { volume })
         }
+        self.player.emit_volume_set_event(volume);
     }
 }
 

examples/play.rs

@@ -7,8 +7,53 @@ use librespot::core::session::Session;
 use librespot::core::spotify_id::SpotifyId;
 use librespot::playback::config::PlayerConfig;
 
+use futures::stream::Stream;
+use futures::{Async, Future, Poll};
 use librespot::playback::audio_backend;
-use librespot::playback::player::Player;
+use librespot::playback::player::{Player, PlayerEvent, PlayerEventChannel};
+
+pub struct SingleTrackPlayer {
+    play_request_id: u64,
+    event_channel: PlayerEventChannel,
+}
+
+impl SingleTrackPlayer {
+    pub fn new(ref mut player: Player, track_id: SpotifyId) -> SingleTrackPlayer {
+        let event_channel = player.get_player_event_channel();
+        let play_request_id = player.load(track_id, true, 0);
+        SingleTrackPlayer {
+            play_request_id,
+            event_channel,
+        }
+    }
+}
+
+impl Future for SingleTrackPlayer {
+    type Item = ();
+    type Error = ();
+
+    fn poll(&mut self) -> Poll<(), ()> {
+        loop {
+            match self.event_channel.poll().unwrap() {
+                Async::NotReady => return Ok(Async::NotReady),
+                Async::Ready(None) => return Ok(Async::Ready(())),
+                Async::Ready(Some(event)) => match event {
+                    PlayerEvent::EndOfTrack {
+                        play_request_id, ..
+                    }
+                    | PlayerEvent::Stopped {
+                        play_request_id, ..
+                    } => {
+                        if play_request_id == self.play_request_id {
+                            return Ok(Async::Ready(()));
+                        }
+                    }
+                    _ => (),
+                },
+            }
+        }
+    }
+}
 
 fn main() {
     let mut core = Core::new().unwrap();
@@ -39,7 +84,7 @@ fn main() {
     });
 
     println!("Playing...");
-    core.run(player.load(track, true, 0)).unwrap();
+    core.run(SingleTrackPlayer::new(player, track)).unwrap();
 
     println!("Done");
 }

metadata/src/lib.rs

@@ -63,6 +63,7 @@ pub struct AudioItem {
     pub uri: String,
     pub files: LinearMap<FileFormat, FileId>,
     pub name: String,
+    pub duration: i32,
     pub available: bool,
     pub alternatives: Option<Vec<SpotifyId>>,
 }
@@ -100,6 +101,7 @@ impl AudioFiles for Track {
                 uri: format!("spotify:track:{}", id.to_base62()),
                 files: item.files,
                 name: item.name,
+                duration: item.duration,
                 available: item.available,
                 alternatives: Some(item.alternatives),
             })
@@ -118,6 +120,7 @@ impl AudioFiles for Episode {
                 uri: format!("spotify:episode:{}", id.to_base62()),
                 files: item.files,
                 name: item.name,
+                duration: item.duration,
                 available: item.available,
                 alternatives: None,
             })

src/player_event_handler.rs

@@ -25,14 +25,15 @@ pub fn run_program_on_events(event: PlayerEvent, onevent: &str) -> io::Result<Ch
             env_vars.insert("OLD_TRACK_ID", old_track_id.to_base62());
             env_vars.insert("TRACK_ID", new_track_id.to_base62());
         }
-        PlayerEvent::Started { track_id } => {
+        PlayerEvent::Started { track_id, .. } => {
             env_vars.insert("PLAYER_EVENT", "start".to_string());
             env_vars.insert("TRACK_ID", track_id.to_base62());
         }
-        PlayerEvent::Stopped { track_id } => {
+        PlayerEvent::Stopped { track_id, .. } => {
             env_vars.insert("PLAYER_EVENT", "stop".to_string());
             env_vars.insert("TRACK_ID", track_id.to_base62());
         }
+        _ => (),
     }
     run_program(onevent, env_vars)
 }