now gapless

meson.build

@@ -1,7 +1,7 @@
 project('wavelet', ['c', 'vala'],
-          version: '0.1.0',
+          version: '0.1.0', # WAVELET_VERSION
     meson_version: '>= 1.0.0',
-  default_options: [ 'warning_level=none', 'werror=false', ],
+  default_options: [ 'warning_level=0', 'werror=false', ],
 )
 
 i18n = import('i18n')

src/api.vala

@@ -167,6 +167,7 @@ public class Wavelet.Subsonic : Object {
         this.parameters = @"u=$(Uri.escape_string(username))&p=$(Uri.escape_string(password))&v=1.16.1&c=eu.callcc.Wavelet";
 
         this.session = new Soup.Session ();
+        this.session.user_agent = "Wavelet/0.1.0 (Linux)"; // WAVELET_VERSION
 
         this.artist_list = new ListStore (typeof (Artist));
         this.album_list = new ListStore (typeof (Album));

src/application.vala

@@ -18,7 +18,6 @@
  * SPDX-License-Identifier: AGPL-3.0-or-later
  */
 
-Gst.Element playbin;
 Wavelet.Subsonic public_api;
 
 public class Wavelet.Application : Adw.Application {
@@ -41,88 +40,9 @@ public class Wavelet.Application : Adw.Application {
 
     public override void activate () {
         base.activate ();
-        // FIXME edit back if issues var win = this.active_window ?? new Wavelet.Window (this);
-        var win = new Wavelet.Window (this);
+        // if this.active_window not null, this isnt the primary instance
+        var win = this.active_window ?? new Wavelet.Window (this);
         win.present ();
-
-        playbin = Gst.ElementFactory.make ("playbin3", null);
-        assert (playbin != null);
-
-        win.notify["volume"].connect ((s, p) => {
-            // gst docs: Volume sliders should usually use a cubic volume.
-            ((Gst.Audio.StreamVolume) playbin).set_volume (Gst.Audio.StreamVolumeFormat.CUBIC, win.volume);
-        });
-
-        win.mute.clicked.connect (() => {
-            var vol = (Gst.Audio.StreamVolume) playbin;
-            if (vol.get_mute ()) {
-                win.show_unmute ();
-                vol.set_mute (false);
-            } else {
-                win.show_mute ();
-                vol.set_mute (true);
-            }
-        });
-
-        Timeout.add (100, () => {
-            int64 position_ns;
-            if (playbin.query_position (Gst.Format.TIME, out position_ns)) {
-                win.play_position_ms = (int) (position_ns / 1000000);
-            }
-            return Source.CONTINUE;
-        });
-
-        playbin.get_bus ().add_watch (Priority.DEFAULT, (bus, message) => {
-            switch (message.type) {
-            case Gst.MessageType.ASYNC_DONE:
-                win.play_position.sensitive = true;
-
-                int64 duration_ns;
-                if (playbin.query_duration (Gst.Format.TIME, out duration_ns)) {
-                    win.play_position_ms = 0;
-                    win.play_duration_ms = (int) (duration_ns / 1000000);
-                } else {
-                    warning ("could not query playbin duration after ASYNC_DONE");
-                }
-
-                break;
-
-            default:
-                break;
-            }
-            return true;
-        });
-
-        win.setup.connected.connect ((api) => {
-            public_api = api;
-
-            win.shuffle_all_tracks.sensitive = true;
-            win.shuffle_all_tracks.activated.connect (() => {
-                win.shuffle_all_tracks.sensitive = false;
-                win.play_queue.clear ();
-                api.get_random_songs.begin (null, (song) => {
-                    win.play_queue.queue (song);
-                }, (obj, res) => {
-                    try {
-                        api.get_random_songs.end (res);
-                    } catch (Error e) {
-                        error ("could not get random songs: %s", e.message);
-                    }
-                    win.shuffle_all_tracks.sensitive = true;
-                });
-            });
-
-            win.play_queue.play_now.connect ((song) => {
-                win.play_position.sensitive = false;
-
-                playbin.set_state (Gst.State.READY);
-                playbin.set ("uri", api.stream_uri (song.id));
-                playbin.set_state (Gst.State.PLAYING);
-
-                win.song = song;
-            });
-        });
-        win.setup.load ();
     }
 
     private void on_about_action () {
@@ -132,7 +52,7 @@ public class Wavelet.Application : Adw.Application {
             application_icon = "eu.callcc.Wavelet",
             developer_name = "Erica Z",
             translator_credits = _("translator-credits"),
-            version = "0.1.0",
+            version = "0.1.0", // WAVELET_VERSION
             developers = developers,
             copyright = "© 2024 Erica Z",
         };

src/meson.build

@@ -3,6 +3,7 @@ wavelet_sources = [
   'application.vala',
   'main.vala',
   'play_queue.vala',
+  'playbin.vala',
   'setup.vala',
   'window.vala',
 ]

src/play_queue.vala

@@ -23,39 +23,40 @@ public class Wavelet.PlayQueue : Adw.NavigationPage {
     [GtkChild] private unowned Gtk.ListView list_view;
 
     private ListStore songs;
-    private uint current;
+    private uint next_song;
 
     public signal void play_now (Song song);
+    public signal void now_playing (Song song);
+    public signal void play_next (Song? song);
 
     construct {
         this.songs = new ListStore (typeof (Song));
-        this.current = 0;
+        this.next_song = 0;
 
         this.list_view.model = new Gtk.NoSelection (this.songs);
     }
 
     public void clear () {
         this.songs.remove_all ();
-        this.current = 0;
     }
 
     public void queue (Song song) {
         this.songs.append (song);
     }
 
-    public void next () {
-        if (this.current < this.songs.get_n_items ()) {
-            this.current += 1;
-        }
-    }
-
-    public Song? peek () {
-        return (Song?) this.songs.get_item (this.current+1);
-    }
-
     [GtkCallback] private void on_song_activate (uint position) {
-        this.current = position;
+        this.next_song = position;
         Song song = (Song) this.songs.get_item (position);
         this.play_now (song);
     }
+
+    internal void on_stream_start (Playbin playbin) {
+        Song song = (Song) this.songs.get_item (this.next_song);
+        this.now_playing (song);
+
+        // prepare for next song gapless
+        this.next_song += 1;
+        Song? next_song = (Song?) this.songs.get_item (this.next_song);
+        this.play_next (next_song);
+    }
 }

src/playbin.vala

@@ -0,0 +1,194 @@
+/* playbin.vala
+ *
+ * Copyright 2024 Erica Z
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+class Playbin : Object {
+    // dynamic: undocumented vala feature
+    // lets us access the about-to-finish signal
+    private dynamic Gst.Element playbin;
+
+    private SourceFunc? async_done_callback;
+
+    // cubic: recommended for media player volume sliders?
+    public double volume {
+        get {
+            return ((Gst.Audio.StreamVolume) this.playbin).get_volume (Gst.Audio.StreamVolumeFormat.CUBIC);
+        }
+        set {
+            ((Gst.Audio.StreamVolume) this.playbin).set_volume (Gst.Audio.StreamVolumeFormat.CUBIC, value);
+        }
+    }
+
+    public bool mute {
+        get { return playbin.mute; }
+        set { playbin.mute = value; }
+    }
+
+    public signal void set_position (int64 position);
+    public int64 duration { get; private set; }
+
+    public signal void stream_started ();
+
+    construct {
+        this.playbin = Gst.ElementFactory.make ("playbin3", null);
+        assert (this.playbin != null);
+
+        //dynamic Gst.Element souphttpsrc = ((Gst.Bin) this.playbin).get_by_name ("souphttpsrc");
+        //assert (souphttpsrc != null);
+        //souphttpsrc.user_agent = "Wavelet/0.1.0 (Linux)"; // WAVELET_VERSION
+
+        // regularly update position
+        Idle.add (() => {
+            int64 new_position;
+            if (this.playbin.query_position (Gst.Format.TIME, out new_position)) {
+                this.set_position (new_position < this.duration ? new_position : this.duration);
+            }
+
+            // rerun when idle
+            return true;
+        });
+
+        this.playbin.get_bus ().add_watch (Priority.DEFAULT, (bus, message) => {
+            // message.type actually seems to be flags
+            if (Gst.MessageType.ERROR in message.type) {
+                Error err;
+                string? debug;
+                message.parse_error (out err, out debug);
+                warning ("gst playbin bus error: %s", err.message);
+            }
+
+            if (Gst.MessageType.ASYNC_DONE in message.type) {
+                assert (this.async_done_callback != null);
+                var cb = (owned) this.async_done_callback;
+                assert (this.async_done_callback == null); // sanity check
+                cb ();
+            }
+
+            if (Gst.MessageType.STREAM_START in message.type) {
+                print ("stream start\n");
+
+                int64 new_duration;
+                assert (this.playbin.query_duration (Gst.Format.TIME, out new_duration));
+                this.duration = new_duration;
+
+                this.next_uri_lock.lock ();
+                this.next_uri = null;
+                this.next_uri_lock.unlock ();
+                
+                this.stream_started ();
+            }
+
+            if (Gst.MessageType.EOS in message.type) {
+                print ("eos\n");
+            }
+
+            return true;
+        });
+
+        this.playbin.about_to_finish.connect (this.on_about_to_finish);
+    }
+
+    private async void set_state (Gst.State state) {
+        assert (this.async_done_callback == null);
+
+        switch (this.playbin.set_state (state)) {
+        case Gst.StateChangeReturn.SUCCESS:
+            break;
+
+        case Gst.StateChangeReturn.ASYNC:
+            this.async_done_callback = this.set_state.callback;
+            yield;
+            break;
+
+        default:
+            assert (false);
+            break;
+        }
+    }
+
+    public async bool seek (int64 position) {
+        // don't actually seek if an operation is pending
+        if (this.async_done_callback != null) {
+            return false;
+        }
+
+        // ASSUMPTION: this can only work asynchronously
+        // (will wait for an ASYNC_DONE in the bus)
+        assert (this.playbin.seek_simple (Gst.Format.TIME, Gst.SeekFlags.FLUSH | Gst.SeekFlags.KEY_UNIT, position));
+        this.async_done_callback = this.seek.callback;
+        yield;
+
+        return true;
+    }
+
+    private string? play_now_queued;
+    // returns true if the "play now" request wasn't overriden by a later call
+    public async bool play_now (string uri) {
+        if (this.async_done_callback != null) {
+            // an operation was already pending
+            // last writer wins here
+            this.play_now_queued = uri;
+            // idle spinning is probably fine
+            while (this.async_done_callback != null) {
+                Idle.add (this.play_now.callback);
+                yield;
+                // only keep spinning if we can still win
+                if (this.play_now_queued != uri) {
+                    return false;
+                }
+            }
+            this.play_now_queued = null;
+        }
+
+        yield this.set_state (Gst.State.READY);
+        this.playbin.uri = uri;
+        yield this.set_state (Gst.State.PLAYING);
+
+        if (this.play_now_queued != null) {
+            // another "play now" was queued while we were busy
+            // defer to it
+            return false;
+        }
+
+        return true;
+    }
+
+    Mutex next_uri_lock;
+    string? next_uri;
+
+    public void set_next_uri (string? next_uri) {
+        this.next_uri_lock.lock ();
+        this.next_uri = next_uri;
+        this.next_uri_lock.unlock ();
+    }
+
+    // called when uri can be switched for gapless playback
+    // need async queue because this might be called from a gstreamer thread
+    private void on_about_to_finish (dynamic Gst.Element playbin) {
+        print("about to finish\n");
+
+        this.next_uri_lock.lock ();
+        string? next_uri = this.next_uri;
+        this.next_uri_lock.unlock ();
+
+        if (next_uri != null) {
+            playbin.uri = next_uri;
+        }
+    }
+}

src/window.blp

@@ -91,18 +91,8 @@ template $WaveletWindow: Adw.ApplicationWindow {
         "toolbar",
       ]
 
-      Overlay {
-        [overlay] Adw.Spinner {
-          halign: center;
-          valign: center;
-          width-request: 20;
-          height-request: 20;
-          visible: bind template.cover_art_loading;
-        }
-
-        Picture {
-          paintable: bind template.playing_cover_art;
-        }
+      Picture {
+        paintable: bind template.playing_cover_art;
       }
 
       Box {
@@ -149,19 +139,20 @@ template $WaveletWindow: Adw.ApplicationWindow {
               "numeric",
             ]
 
-            label: bind $format_timestamp (template.play_position_ms) as <string>;
+            label: bind $format_timestamp (template.position) as <string>;
           }
 
           Scale play_position {
             orientation: horizontal;
             width-request: 200;
-            sensitive: false;
 
             adjustment: Adjustment {
               lower: 0;
-              value: bind template.play_position_ms bidirectional;
-              upper: bind template.play_duration_ms;
+              value: bind template.position;
+              upper: bind template.playbin as <$Playbin>.duration;
             };
+
+            change-value => $on_play_position_seek ();
           }
 
           Label play_duration {
@@ -170,7 +161,7 @@ template $WaveletWindow: Adw.ApplicationWindow {
               "numeric",
             ]
 
-            label: bind $format_timestamp (template.play_duration_ms) as <string>;
+            label: bind $format_timestamp (template.playbin as <$Playbin>.duration) as <string>;
           }
         }
       }
@@ -191,6 +182,8 @@ template $WaveletWindow: Adw.ApplicationWindow {
       Button {
         icon-name: "media-playback-start";
         valign: center;
+
+        clicked => $on_play_pause_clicked ();
       }
 
       Button {

src/window.vala

@@ -30,10 +30,9 @@ public class Wavelet.Window : Adw.ApplicationWindow {
     [GtkChild] public unowned Adw.ButtonRow shuffle_all_tracks;
 
     [GtkChild] public unowned Gtk.Button mute;
-    [GtkChild] public unowned Gtk.Scale play_position;
     
-    public int play_position_ms { get; set; default = 0; }
-    public int play_duration_ms { get; set; default = 1; }
+    [GtkChild] private unowned Gtk.Scale play_position;
+    public int64 position { get; private set; }
 
     public double volume { get; set; default = 1.0; }
 
@@ -43,11 +42,52 @@ public class Wavelet.Window : Adw.ApplicationWindow {
     public bool cover_art_loading { get; set; default = false; }
     public Gdk.Paintable playing_cover_art { get; set; }
 
+    internal Playbin playbin { get; default = new Playbin (); }
+
     public Window (Gtk.Application app) {
         Object (application: app);
     }
 
     construct {
+        this.setup.connected.connect ((api) => {
+            public_api = api;
+
+            this.shuffle_all_tracks.sensitive = true;
+            this.shuffle_all_tracks.activated.connect (() => {
+                this.shuffle_all_tracks.sensitive = false;
+                this.play_queue.clear ();
+                api.get_random_songs.begin (null, (song) => {
+                    this.play_queue.queue (song);
+                }, (obj, res) => {
+                    try {
+                        api.get_random_songs.end (res);
+                    } catch (Error e) {
+                        error ("could not get random songs: %s", e.message);
+                    }
+                    this.shuffle_all_tracks.sensitive = true;
+                });
+            });
+
+            playbin.stream_started.connect (this.play_queue.on_stream_start);
+
+            this.play_queue.now_playing.connect ((song) => {
+                print ("now playing %s\n", song.title);
+                this.song = song;
+            });
+
+            this.play_queue.play_now.connect ((song) => {
+                playbin.play_now.begin (api.stream_uri (song.id));
+            });
+            this.play_queue.play_next.connect ((song) => {
+                if (song == null) {
+                    playbin.set_next_uri (null);
+                } else {
+                    playbin.set_next_uri (api.stream_uri (song.id));
+                }
+            });
+        });
+        this.setup.load ();
+
         this.sidebar.select_row (this.sidebar.get_row_at_index (0));
 
         this.notify["song"].connect (() => {
@@ -74,7 +114,14 @@ public class Wavelet.Window : Adw.ApplicationWindow {
                 });
             }
         });
-        this.set("song", null);
+        this.song = null;
+
+        this.playbin.set_position.connect ((sender, new_position) => {
+            // only set if we aren't seeking
+            if (this.seek_timeout_id == 0) {
+                this.position = new_position;
+            }
+        });
     }
 
     public void show_mute () {
@@ -93,8 +140,26 @@ public class Wavelet.Window : Adw.ApplicationWindow {
         }
     }
 
-    [GtkCallback] private string format_timestamp (int ms) {
-        int s = ms / 1000;
+    [GtkCallback] private string format_timestamp (int64 ns) {
+        int64 ms = ns / 1000000;
+        int s = (int) (ms / 1000);
         return "%02d:%02d".printf (s/60, s%60);
     }
+
+    [GtkCallback] private void on_play_pause_clicked () {
+    }
+
+    // same timeout logic as https://code.videolan.org/videolan/npapi-vlc/blob/6eae0ffb9cbaf8f6e04423de2ff38daabdf7cae3/npapi/vlcplugin_gtk.cpp#L312
+    private uint seek_timeout_id = 0;
+    [GtkCallback] private bool on_play_position_seek (Gtk.Range range, Gtk.ScrollType scroll_type, double value) {
+        if (this.seek_timeout_id == 0) {
+            this.seek_timeout_id = Timeout.add (500, () => {
+                playbin.seek.begin ((int64) range.adjustment.value, (obj, res) => {
+                    this.seek_timeout_id = 0;
+                });
+                return false;
+            });
+        }
+        return false;
+    }
 }