player/Control: Play*() returns Error information

src/Partition.hxx

@@ -123,20 +123,20 @@ struct Partition final : private PlayerListener, private MixerListener {
 		playlist.Stop(pc);
 	}
 
-	void PlayPosition(int position) {
-		playlist.PlayPosition(pc, position);
+	bool PlayPosition(int position, Error &error) {
+		return playlist.PlayPosition(pc, position, error);
 	}
 
-	void PlayId(int id) {
-		playlist.PlayId(pc, id);
+	bool PlayId(int id, Error &error) {
+		return playlist.PlayId(pc, id, error);
 	}
 
-	void PlayNext() {
-		playlist.PlayNext(pc);
+	bool PlayNext(Error &error) {
+		return playlist.PlayNext(pc, error);
 	}
 
-	void PlayPrevious() {
-		playlist.PlayPrevious(pc);
+	bool PlayPrevious(Error &error) {
+		return playlist.PlayPrevious(pc, error);
 	}
 
 	bool SeekSongPosition(unsigned song_position,

src/command/PlayerCommands.cxx

@@ -60,16 +60,22 @@ CommandResult
 handle_play(Client &client, Request args, gcc_unused Response &r)
 {
 	int song = args.ParseOptional(0, -1);
-	client.partition.PlayPosition(song);
-	return CommandResult::OK;
+
+	Error error;
+	return client.partition.PlayPosition(song, error)
+		? CommandResult::OK
+		: print_error(r, error);
 }
 
 CommandResult
 handle_playid(Client &client, Request args, gcc_unused Response &r)
 {
 	int id = args.ParseOptional(0, -1);
-	client.partition.PlayId(id);
-	return CommandResult::OK;
+
+	Error error;
+	return client.partition.PlayId(id, error)
+		? CommandResult::OK
+		: print_error(r, error);
 }
 
 CommandResult
@@ -212,18 +218,24 @@ handle_next(Client &client, gcc_unused Request args, gcc_unused Response &r)
 	const bool single = playlist.queue.single;
 	playlist.queue.single = false;
 
-	client.partition.PlayNext();
+	Error error;
+	bool success = client.partition.PlayNext(error);
 
 	playlist.queue.single = single;
-	return CommandResult::OK;
+
+	return success
+		? CommandResult::OK
+		: print_error(r, error);
 }
 
 CommandResult
 handle_previous(Client &client, gcc_unused Request args,
 		gcc_unused Response &r)
 {
-	client.partition.PlayPrevious();
-	return CommandResult::OK;
+	Error error;
+	return client.partition.PlayPrevious(error)
+		? CommandResult::OK
+		: print_error(r, error);
 }
 
 CommandResult

src/player/Control.cxx

@@ -49,18 +49,20 @@ PlayerControl::~PlayerControl()
 	delete tagged_song;
 }
 
-void
-PlayerControl::Play(DetachedSong *song)
+bool
+PlayerControl::Play(DetachedSong *song, Error &error_r)
 {
 	assert(song != nullptr);
 
 	const ScopeLock protect(mutex);
-	SeekLocked(song, SongTime::zero(), IgnoreError());
+	bool success = SeekLocked(song, SongTime::zero(), error_r);
 
-	if (state == PlayerState::PAUSE)
+	if (success && state == PlayerState::PAUSE)
 		/* if the player was paused previously, we need to
 		   unpause it */
 		PauseLocked();
+
+	return success;
 }
 
 void

src/player/Control.hxx

@@ -311,7 +311,7 @@ public:
 	 * @param song the song to be queued; the given instance will
 	 * be owned and freed by the player
 	 */
-	void Play(DetachedSong *song);
+	bool Play(DetachedSong *song, Error &error);
 
 	/**
 	 * see PlayerCommand::CANCEL

src/queue/Playlist.cxx

@@ -152,8 +152,8 @@ playlist::UpdateQueuedSong(PlayerControl &pc, const DetachedSong *prev)
 	}
 }
 
-void
-playlist::PlayOrder(PlayerControl &pc, int order)
+bool
+playlist::PlayOrder(PlayerControl &pc, int order, Error &error)
 {
 	playing = true;
 	queued = -1;
@@ -162,10 +162,14 @@ playlist::PlayOrder(PlayerControl &pc, int order)
 
 	FormatDebug(playlist_domain, "play %i:\"%s\"", order, song.GetURI());
 
-	pc.Play(new DetachedSong(song));
 	current = order;
 
+	if (!pc.Play(new DetachedSong(song), error))
+		return false;
+
 	SongStarted();
+
+	return true;
 }
 
 void
@@ -224,7 +228,8 @@ playlist::ResumePlayback(PlayerControl &pc)
 		Stop(pc);
 	else
 		/* continue playback at the next song */
-		PlayNext(pc);
+		/* TODO: log error? */
+		PlayNext(pc, IgnoreError());
 }
 
 void

src/queue/Playlist.hxx

@@ -262,15 +262,15 @@ public:
 
 	void Stop(PlayerControl &pc);
 
-	void PlayPosition(PlayerControl &pc, int position);
+	bool PlayPosition(PlayerControl &pc, int position, Error &error);
 
-	void PlayOrder(PlayerControl &pc, int order);
+	bool PlayOrder(PlayerControl &pc, int order, Error &error);
 
-	void PlayId(PlayerControl &pc, int id);
+	bool PlayId(PlayerControl &pc, int id, Error &error);
 
-	void PlayNext(PlayerControl &pc);
+	bool PlayNext(PlayerControl &pc, Error &error);
 
-	void PlayPrevious(PlayerControl &pc);
+	bool PlayPrevious(PlayerControl &pc, Error &error);
 
 	bool SeekSongOrder(PlayerControl &pc,
 			   unsigned song_order,

src/queue/PlaylistControl.cxx

@@ -56,8 +56,8 @@ playlist::Stop(PlayerControl &pc)
 	}
 }
 
-void
-playlist::PlayPosition(PlayerControl &pc, int song)
+bool
+playlist::PlayPosition(PlayerControl &pc, int song, Error &error)
 {
 	pc.LockClearError();
 
@@ -66,13 +66,13 @@ playlist::PlayPosition(PlayerControl &pc, int song)
 		/* play any song ("current" song, or the first song */
 
 		if (queue.IsEmpty())
-			return;
+			return true;
 
 		if (playing) {
 			/* already playing: unpause playback, just in
 			   case it was paused, and return */
 			pc.LockSetPause(false);
-			return;
+			return true;
 		}
 
 		/* select a song: "current" song, or the first one */
@@ -102,29 +102,30 @@ playlist::PlayPosition(PlayerControl &pc, int song)
 	stop_on_error = false;
 	error_count = 0;
 
-	PlayOrder(pc, i);
+	return PlayOrder(pc, i, error);
 }
 
-void
-playlist::PlayId(PlayerControl &pc, int id)
+bool
+playlist::PlayId(PlayerControl &pc, int id, Error &error)
 {
-	if (id == -1) {
-		PlayPosition(pc, id);
-		return;
-	}
+	if (id == -1)
+		return PlayPosition(pc, id, error);
 
 	int song = queue.IdToPosition(id);
 	if (song < 0)
 		throw PlaylistError::NoSuchSong();
 
-	return PlayPosition(pc, song);
+	return PlayPosition(pc, song, error);
 }
 
-void
-playlist::PlayNext(PlayerControl &pc)
+bool
+playlist::PlayNext(PlayerControl &pc, Error &error)
 {
-	if (!playing)
-		return;
+	if (!playing) {
+		error.Set(playlist_domain, int(PlaylistResult::NOT_PLAYING),
+			  "Not playing");
+		return true;
+	}
 
 	assert(!queue.IsEmpty());
 	assert(queue.IsValidOrder(current));
@@ -158,19 +159,25 @@ playlist::PlayNext(PlayerControl &pc)
 			   discard them anyway */
 		}
 
-		PlayOrder(pc, next_order);
+		if (!PlayOrder(pc, next_order, error))
+			return false;
 	}
 
 	/* Consume mode removes each played songs. */
 	if (queue.consume)
 		DeleteOrder(pc, old_current);
+
+	return true;
 }
 
-void
-playlist::PlayPrevious(PlayerControl &pc)
+bool
+playlist::PlayPrevious(PlayerControl &pc, Error &error)
 {
-	if (!playing)
-		return;
+	if (!playing) {
+		error.Set(playlist_domain, int(PlaylistResult::NOT_PLAYING),
+			  "Not playing");
+		return true;
+	}
 
 	assert(!queue.IsEmpty());
 
@@ -187,7 +194,7 @@ playlist::PlayPrevious(PlayerControl &pc)
 		order = current;
 	}
 
-	PlayOrder(pc, order);
+	return PlayOrder(pc, order, error);
 }
 
 bool

src/queue/PlaylistEdit.cxx

@@ -239,7 +239,8 @@ playlist::DeleteInternal(PlayerControl &pc,
 
 		if (current >= 0 && !paused)
 			/* play the song after the deleted one */
-			PlayOrder(pc, current);
+			/* TODO: log error? */
+			PlayOrder(pc, current, IgnoreError());
 		else {
 			/* stop the player */
 

src/queue/PlaylistState.cxx

@@ -196,7 +196,8 @@ playlist_state_restore(const char *line, TextFile &file,
 		if (state == PlayerState::STOP /* && config_option */)
 			playlist.current = current;
 		else if (seek_time.count() == 0)
-			playlist.PlayPosition(pc, current);
+			/* TODO: log error? */
+			playlist.PlayPosition(pc, current, IgnoreError());
 		else
 			playlist.SeekSongPosition(pc, current, seek_time,
 						  IgnoreError());