warn on failed seek

src/playbin.vala

@@ -43,9 +43,6 @@ public class Playbin : GLib.Object {
     // signalled when the last track is over
     public signal void stopped ();
 
-    // set to false when manually switching tracks
-    private bool inc_position;
-
     // these are mostly synced with mpv
     public double position { get; private set; default = 0.0; }
     public double duration { get; private set; default = 0.0; }
@@ -143,11 +140,6 @@ public class Playbin : GLib.Object {
 
                     case Mpv.EventId.START_FILE:
                         debug ("START_FILE received");
-                        if (this.inc_position) {
-                            this.play_queue_position += 1;
-                        } else {
-                            this.inc_position = true;
-                        }
 
                         // estimate duration from api data
                         // while mpv doesn't know it
@@ -157,18 +149,23 @@ public class Playbin : GLib.Object {
                         break;
 
                     case Mpv.EventId.END_FILE:
-                        debug ("END_FILE received");
                         var data = event.parse_end_file ();
+                        debug (@"END_FILE received (reason: $(data.reason))");
+
                         if (data.error < 0) {
                             warning ("playback of track aborted: %s", data.error.to_string ());
                         }
 
-                        if (this.inc_position && this.play_queue_position+1 == this._play_queue.get_n_items ()) {
-                            // reached the end (?)
+                        if (data.reason == Mpv.EndFileReason.EOF) {
+                            // assume this is a proper transition
                             this.play_queue_position += 1;
+
+                            if (this.play_queue_position == this._play_queue.get_n_items ()) {
+                                // reached the end (?)
                                 this.state = PlaybinState.STOPPED;
                                 this.stopped ();
                             }
+                        }
 
                         break;
                       
@@ -185,8 +182,12 @@ public class Playbin : GLib.Object {
     }
 
     public void seek (double position) {
+        var rc = this.mpv.command ({"seek", position.to_string (), "absolute"});
+        if (rc < 0) {
+            warning (@"could not seek to $position: $rc");
+        } else {
             this.position = position;
-        assert (this.mpv.command ({"seek", position.to_string (), "absolute"}) >= 0);
+        }
     }
 
     // manually changes which track in the play queue to play
@@ -196,7 +197,6 @@ public class Playbin : GLib.Object {
         assert (this.mpv.command ({"playlist-play-index", position.to_string ()}) >= 0);
         this.state = PlaybinState.PLAYING;
         this.play_queue_position = position;
-        this.inc_position = false;
     }
 
     public void pause () {
@@ -224,7 +224,6 @@ public class Playbin : GLib.Object {
             requires (this.state != PlaybinState.STOPPED)
     {
         if (this.play_queue_position+1 < this._play_queue.get_n_items ()) {
-            this.inc_position = false;
             this.play_queue_position += 1;
             assert (this.mpv.command ({"playlist-next-playlist"}) >= 0);
         } else {
@@ -236,7 +235,6 @@ public class Playbin : GLib.Object {
             requires (this.state != PlaybinState.STOPPED)
     {
         if (this.play_queue_position > 0) {
-            this.inc_position = false;
             this.play_queue_position -= 1;
             assert (this.mpv.command ({"playlist-prev-playlist"}) >= 0);
         } else {