playlist: don't pass "fd" to playlist.c functions

The playlist library shouldn't talk to the client if possible.
Introduce the "enum playlist_result" type which the caller
(i.e. command.c) may use to generate an error message.

4 files changed, 245 insertions, 185 deletions

diff --git a/src/command.c b/src/command.c
index 14932b7d2..a4d785126 100644
--- a/src/command.c
+++ b/src/command.c
@@ -218,6 +218,53 @@ static int mpd_fprintf__ check_int(int fd, int *dst,
 	return 0;
 }
 
+static int print_playlist_result(int fd, enum playlist_result result)
+{
+	switch (result) {
+	case PLAYLIST_RESULT_SUCCESS:
+		return 0;
+
+	case PLAYLIST_RESULT_ERRNO:
+		commandError(fd, ACK_ERROR_SYSTEM, strerror(errno));
+		return -1;
+
+	case PLAYLIST_RESULT_NO_SUCH_SONG:
+		commandError(fd, ACK_ERROR_NO_EXIST, "No such song");
+		return -1;
+
+	case PLAYLIST_RESULT_NO_SUCH_LIST:
+		commandError(fd, ACK_ERROR_NO_EXIST, "No such playlist");
+		return -1;
+
+	case PLAYLIST_RESULT_LIST_EXISTS:
+		commandError(fd, ACK_ERROR_NO_EXIST,
+			     "Playlist already exists");
+		return -1;
+
+	case PLAYLIST_RESULT_BAD_NAME:
+		commandError(fd, ACK_ERROR_ARG,
+			     "playlist name is invalid: "
+			     "playlist names may not contain slashes,"
+			     " newlines or carriage returns");
+		return -1;
+
+	case PLAYLIST_RESULT_BAD_RANGE:
+		commandError(fd, ACK_ERROR_ARG, "Bad song index");
+		return -1;
+
+	case PLAYLIST_RESULT_NOT_PLAYING:
+		commandError(fd, ACK_ERROR_PLAYER_SYNC, "Not playing");
+		return -1;
+
+	case PLAYLIST_RESULT_TOO_LARGE:
+		commandError(fd, ACK_ERROR_PLAYLIST_MAX,
+			     "playlist is at the max size");
+		return -1;
+	}
+
+	assert(0);
+}
+
 static void addCommand(const char *name,
 		       int reqPermission,
 		       int minargs,
@@ -253,21 +300,25 @@ static int handlePlay(int fd, mpd_unused int *permission,
 		      int argc, char *argv[])
 {
 	int song = -1;
+	enum playlist_result result;
 
 	if (argc == 2 && check_int(fd, &song, argv[1], need_positive) < 0)
 		return -1;
-	return playPlaylist(fd, song, 0);
+	result = playPlaylist(song, 0);
+	return print_playlist_result(fd, result);
 }
 
 static int handlePlayId(int fd, mpd_unused int *permission,
 			int argc, char *argv[])
 {
 	int id = -1;
+	enum playlist_result result;
 
 	if (argc == 2 && check_int(fd, &id, argv[1], need_positive) < 0)
 		return -1;
 
-	return playPlaylistById(fd, id, 0);
+	result = playPlaylistById(id, 0);
+	return print_playlist_result(fd, result);
 }
 
 static int handleStop(mpd_unused int fd, mpd_unused int *permission,
@@ -281,11 +332,13 @@ static int handleCurrentSong(int fd, mpd_unused int *permission,
 			     mpd_unused int argc, mpd_unused char *argv[])
 {
 	int song = getPlaylistCurrentSong();
+	enum playlist_result result;
 
-	if (song >= 0) {
-		return playlistInfo(fd, song);
-	} else
+	if (song < 0)
 		return 0;
+
+	result = playlistInfo(fd, song);
+	return print_playlist_result(fd, result);
 }
 
 static int handlePause(int fd, mpd_unused int *permission,
@@ -382,54 +435,65 @@ static int handleAdd(int fd, mpd_unused int *permission,
 		     mpd_unused int argc, char *argv[])
 {
 	char *path = argv[1];
+	enum playlist_result result;
 
 	if (isRemoteUrl(path))
-		return addToPlaylist(fd, path, NULL);
+		return addToPlaylist(path, NULL);
 
-	return addAllIn(fd, path);
+	result = addAllIn(fd, path);
+	return print_playlist_result(fd, result);
 }
 
 static int handleAddId(int fd, mpd_unused int *permission,
 		       int argc, char *argv[])
 {
 	int added_id;
-	int ret = addToPlaylist(fd, argv[1], &added_id);
-
-	if (!ret) {
-		if (argc == 3) {
-			int to;
-			if (check_int(fd, &to, argv[2],
-			              check_integer, argv[2]) < 0)
-				return -1;
-			ret = moveSongInPlaylistById(fd, added_id, to);
-			if (ret) { /* move failed */
-				deleteFromPlaylistById(fd, added_id);
-				return ret;
-			}
+	enum playlist_result result = addToPlaylist(argv[1], &added_id);
+
+	if (result == PLAYLIST_RESULT_SUCCESS)
+		return result;
+
+	if (argc == 3) {
+		int to;
+		if (check_int(fd, &to, argv[2],
+			      check_integer, argv[2]) < 0)
+			return -1;
+		result = moveSongInPlaylistById(added_id, to);
+		if (result != PLAYLIST_RESULT_SUCCESS) {
+			int ret = print_playlist_result(fd, result);
+			deleteFromPlaylistById(added_id);
+			return ret;
 		}
-		fdprintf(fd, "Id: %d\n", added_id);
 	}
-	return ret;
+
+	fdprintf(fd, "Id: %d\n", added_id);
+	return result;
 }
 
 static int handleDelete(int fd, mpd_unused int *permission,
 			mpd_unused int argc, char *argv[])
 {
 	int song;
+	enum playlist_result result;
 
 	if (check_int(fd, &song, argv[1], need_positive) < 0)
 		return -1;
-	return deleteFromPlaylist(fd, song);
+
+	result = deleteFromPlaylist(song);
+	return print_playlist_result(fd, result);
 }
 
 static int handleDeleteId(int fd, mpd_unused int *permission,
 			  mpd_unused int argc, char *argv[])
 {
 	int id;
+	enum playlist_result result;
 
 	if (check_int(fd, &id, argv[1], need_positive) < 0)
 		return -1;
-	return deleteFromPlaylistById(fd, id);
+
+	result = deleteFromPlaylistById(id);
+	return print_playlist_result(fd, result);
 }
 
 static int handlePlaylist(int fd, mpd_unused int *permission,
@@ -439,10 +503,10 @@ static int handlePlaylist(int fd, mpd_unused int *permission,
 	return 0;
 }
 
-static int handleShuffle(int fd, mpd_unused int *permission,
+static int handleShuffle(mpd_unused int fd, mpd_unused int *permission,
 			 mpd_unused int argc, mpd_unused char *argv[])
 {
-	shufflePlaylist(fd);
+	shufflePlaylist();
 	return 0;
 }
 
@@ -456,7 +520,10 @@ static int handleClear(mpd_unused int fd, mpd_unused int *permission,
 static int handleSave(int fd, mpd_unused int *permission,
 		      mpd_unused int argc, char *argv[])
 {
-	return savePlaylist(fd, argv[1]);
+	enum playlist_result result;
+
+	result = savePlaylist(argv[1]);
+	return print_playlist_result(fd, result);
 }
 
 static int handleLoad(int fd, mpd_unused int *permission,
@@ -497,7 +564,10 @@ static int handleLsInfo(int fd, mpd_unused int *permission,
 static int handleRm(int fd, mpd_unused int *permission,
 		    mpd_unused int argc, char *argv[])
 {
-	return deletePlaylist(fd, argv[1]);
+	enum playlist_result result;
+
+	result = deletePlaylist(argv[1]);
+	return print_playlist_result(fd, result);
 }
 
 static int handleRename(int fd, mpd_unused int *permission,
@@ -530,20 +600,26 @@ static int handlePlaylistInfo(int fd, mpd_unused int *permission,
 			      int argc, char *argv[])
 {
 	int song = -1;
+	enum playlist_result result;
 
 	if (argc == 2 && check_int(fd, &song, argv[1], need_positive) < 0)
 		return -1;
-	return playlistInfo(fd, song);
+
+	result = playlistInfo(fd, song);
+	return print_playlist_result(fd, result);
 }
 
 static int handlePlaylistId(int fd, mpd_unused int *permission,
 			    int argc, char *argv[])
 {
 	int id = -1;
+	enum playlist_result result;
 
 	if (argc == 2 && check_int(fd, &id, argv[1], need_positive) < 0)
 		return -1;
-	return playlistId(fd, id);
+
+	result = playlistId(fd, id);
+	return print_playlist_result(fd, result);
 }
 
 static int handleFind(int fd, mpd_unused int *permission,
@@ -869,72 +945,86 @@ static int handleMove(int fd, mpd_unused int *permission,
 		      mpd_unused int argc, char *argv[])
 {
 	int from, to;
+	enum playlist_result result;
 
 	if (check_int(fd, &from, argv[1], check_integer, argv[1]) < 0)
 		return -1;
 	if (check_int(fd, &to, argv[2], check_integer, argv[2]) < 0)
 		return -1;
-	return moveSongInPlaylist(fd, from, to);
+	result = moveSongInPlaylist(from, to);
+	return print_playlist_result(fd, result);
 }
 
 static int handleMoveId(int fd, mpd_unused int *permission,
 			mpd_unused int argc, char *argv[])
 {
 	int id, to;
+	enum playlist_result result;
 
 	if (check_int(fd, &id, argv[1], check_integer, argv[1]) < 0)
 		return -1;
 	if (check_int(fd, &to, argv[2], check_integer, argv[2]) < 0)
 		return -1;
-	return moveSongInPlaylistById(fd, id, to);
+	result = moveSongInPlaylistById(id, to);
+	return print_playlist_result(fd, result);
 }
 
 static int handleSwap(int fd, mpd_unused int *permission,
 		      mpd_unused int argc, char *argv[])
 {
 	int song1, song2;
+	enum playlist_result result;
 
 	if (check_int(fd, &song1, argv[1], check_integer, argv[1]) < 0)
 		return -1;
 	if (check_int(fd, &song2, argv[2], check_integer, argv[2]) < 0)
 		return -1;
-	return swapSongsInPlaylist(fd, song1, song2);
+	result = swapSongsInPlaylist(song1, song2);
+	return print_playlist_result(fd, result);
 }
 
 static int handleSwapId(int fd, mpd_unused int *permission,
 			mpd_unused int argc, char *argv[])
 {
 	int id1, id2;
+	enum playlist_result result;
 
 	if (check_int(fd, &id1, argv[1], check_integer, argv[1]) < 0)
 		return -1;
 	if (check_int(fd, &id2, argv[2], check_integer, argv[2]) < 0)
 		return -1;
-	return swapSongsInPlaylistById(fd, id1, id2);
+	result = swapSongsInPlaylistById(id1, id2);
+	return print_playlist_result(fd, result);
 }
 
 static int handleSeek(int fd, mpd_unused int *permission,
 		      mpd_unused int argc, char *argv[])
 {
 	int song, seek_time;
+	enum playlist_result result;
 
 	if (check_int(fd, &song, argv[1], check_integer, argv[1]) < 0)
 		return -1;
 	if (check_int(fd, &seek_time, argv[2], check_integer, argv[2]) < 0)
 		return -1;
-	return seekSongInPlaylist(fd, song, seek_time);
+
+	result = seekSongInPlaylist(song, seek_time);
+	return print_playlist_result(fd, result);
 }
 
 static int handleSeekId(int fd, mpd_unused int *permission,
 			mpd_unused int argc, char *argv[])
 {
 	int id, seek_time;
+	enum playlist_result result;
 
 	if (check_int(fd, &id, argv[1], check_integer, argv[1]) < 0)
 		return -1;
 	if (check_int(fd, &seek_time, argv[2], check_integer, argv[2]) < 0)
 		return -1;
-	return seekSongInPlaylistById(fd, id, seek_time);
+
+	result = seekSongInPlaylistById(id, seek_time);
+	return print_playlist_result(fd, result);
 }
 
 static int handleListAllInfo(int fd, mpd_unused int *permission,
diff --git a/src/dbUtils.c b/src/dbUtils.c
index 8c499ec7e..ff184dc49 100644
--- a/src/dbUtils.c
+++ b/src/dbUtils.c
@@ -173,10 +173,10 @@ int printAllIn(int fd, const char *name)
 			     printDirectoryInDirectory, NULL);
 }
 
-static int directoryAddSongToPlaylist(int fd, Song * song,
+static int directoryAddSongToPlaylist(mpd_unused int fd, Song * song,
 				      mpd_unused void *data)
 {
-	return addSongToPlaylist(fd, song, NULL);
+	return addSongToPlaylist(song, NULL);
 }
 
 static int directoryAddSongToStoredPlaylist(int fd, Song *song, void *data)
diff --git a/src/playlist.c b/src/playlist.c
index 7d782c1a1..9271bb037 100644
--- a/src/playlist.c
+++ b/src/playlist.c
@@ -301,13 +301,12 @@ static void loadPlaylistFromStateFile(FILE *fp, char *buffer,
 		song = atoi(temp);
 		if (!(temp = strtok(NULL, "")))
 			state_file_fatal();
-		if (!addToPlaylist(STDERR_FILENO, temp, NULL)
+		if (addToPlaylist(temp, NULL) == PLAYLIST_RESULT_SUCCESS
 		    && current == song) {
 			if (state == OB_STATE_PAUSE)
 				ob_trigger_action(OB_ACTION_PAUSE_SET);
 			if (state != OB_STATE_STOP) {
-				seekSongInPlaylist(STDERR_FILENO,
-						   playlist.length - 1,
+				seekSongInPlaylist(playlist.length - 1,
 						   seek_time);
 			}
 		}
@@ -428,7 +427,7 @@ int playlistChangesPosId(int fd, mpd_uint32 version)
 	return 0;
 }
 
-int playlistInfo(int fd, int song)
+enum playlist_result playlistInfo(int fd, int song)
 {
 	int i;
 	int begin = 0;
@@ -438,36 +437,31 @@ int playlistInfo(int fd, int song)
 		begin = song;
 		end = song + 1;
 	}
-	if (song >= playlist.length) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", song);
-		return -1;
-	}
+	if (song >= playlist.length)
+		return PLAYLIST_RESULT_BAD_RANGE;
 
 	for (i = begin; i < end; i++)
 		printPlaylistSongInfo(fd, i);
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-# define checkSongId(id) { \
-	if(id < 0 || id >= PLAYLIST_HASH_MULT*playlist_max_length || \
-			playlist.idToPosition[id] == -1 ) \
-	{ \
-		commandError(fd, ACK_ERROR_NO_EXIST, \
-			"song id doesn't exist: \"%i\"", id); \
-		return -1; \
-	} \
+static int song_id_exists(int id)
+{
+	return id >= 0 && id < PLAYLIST_HASH_MULT*playlist_max_length &&
+		playlist.idToPosition[id] != -1;
 }
 
-int playlistId(int fd, int id)
+enum playlist_result playlistId(int fd, int id)
 {
 	int i;
 	int begin = 0;
 	int end = playlist.length;
 
 	if (id >= 0) {
-		checkSongId(id);
+		if (!song_id_exists(id))
+			return PLAYLIST_RESULT_NO_SUCH_SONG;
+
 		begin = playlist.idToPosition[id];
 		end = begin + 1;
 	}
@@ -475,7 +469,7 @@ int playlistId(int fd, int id)
 	for (i = begin; i < end; i++)
 		printPlaylistSongInfo(fd, i);
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
 static void swapSongs(int song1, int song2)
@@ -595,7 +589,7 @@ static int clear_queue(void)
 	return playlist.queued;
 }
 
-int addToPlaylist(int fd, const char *url, int *added_id)
+enum playlist_result addToPlaylist(const char *url, int *added_id)
 {
 	Song *song;
 
@@ -604,13 +598,10 @@ int addToPlaylist(int fd, const char *url, int *added_id)
 	if ((song = getSongFromDB(url))) {
 	} else if (!(isValidRemoteUtf8Url(url) &&
 		     (song = newSong(url, SONG_TYPE_URL, NULL)))) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "\"%s\" is not in the music db or is "
-			     "not a valid url", url);
-		return -1;
+		return PLAYLIST_RESULT_NO_SUCH_SONG;
 	}
 
-	return addSongToPlaylist(fd, song, added_id);
+	return addSongToPlaylist(song, added_id);
 }
 
 int addToStoredPlaylist(int fd, const char *url, const char *utf8file)
@@ -641,15 +632,12 @@ fail:
 	return -1;
 }
 
-int addSongToPlaylist(int fd, Song * song, int *added_id)
+enum playlist_result addSongToPlaylist(Song * song, int *added_id)
 {
 	int id;
 
-	if (playlist.length == playlist_max_length) {
-		commandError(fd, ACK_ERROR_PLAYLIST_MAX,
-			     "playlist is at the max size");
-		return -1;
-	}
+	if (playlist.length == playlist_max_length)
+		return PLAYLIST_RESULT_TOO_LARGE;
 
 	if (playlist_state == PLAYLIST_STATE_PLAY) {
 		if (playlist.queued >= 0
@@ -692,24 +680,17 @@ int addSongToPlaylist(int fd, Song * song, int *added_id)
 	if (added_id)
 		*added_id = id;
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-int swapSongsInPlaylist(int fd, int song1, int song2)
+enum playlist_result swapSongsInPlaylist(int song1, int song2)
 {
 	int queuedSong = -1;
 	int currentSong;
 
-	if (song1 < 0 || song1 >= playlist.length) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", song1);
-		return -1;
-	}
-	if (song2 < 0 || song2 >= playlist.length) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", song2);
-		return -1;
-	}
+	if (song1 < 0 || song1 >= playlist.length ||
+	    song2 < 0 || song2 >= playlist.length)
+		return PLAYLIST_RESULT_BAD_RANGE;
 
 	if (playlist_state == PLAYLIST_STATE_PLAY) {
 		if (playlist.queued >= 0) {
@@ -747,15 +728,15 @@ int swapSongsInPlaylist(int fd, int song1, int song2)
 
 	incrPlaylistVersion();
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-int swapSongsInPlaylistById(int fd, int id1, int id2)
+enum playlist_result swapSongsInPlaylistById(int id1, int id2)
 {
-	checkSongId(id1);
-	checkSongId(id2);
+	if (!song_id_exists(id1) || !song_id_exists(id2))
+		return PLAYLIST_RESULT_NO_SUCH_SONG;
 
-	return swapSongsInPlaylist(fd, playlist.idToPosition[id1],
+	return swapSongsInPlaylist(playlist.idToPosition[id1],
 				   playlist.idToPosition[id2]);
 }
 
@@ -766,18 +747,15 @@ int swapSongsInPlaylistById(int fd, int id1, int id2)
 	playlist.songMod[to] = playlist.version; \
 }
 
-int deleteFromPlaylist(int fd, int song)
+enum playlist_result deleteFromPlaylist(int song)
 {
 	int i;
 	int songOrder;
 	int stop_current = 0;
 	int prev_queued = playlist.queued;
 
-	if (song < 0 || song >= playlist.length) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", song);
-		return -1;
-	}
+	if (song < 0 || song >= playlist.length)
+		return PLAYLIST_RESULT_BAD_RANGE;
 
 	if (playlist_state == PLAYLIST_STATE_PLAY) {
 		if (prev_queued >= 0
@@ -842,14 +820,15 @@ int deleteFromPlaylist(int fd, int song)
 		queueNextSongInPlaylist();
 	}
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-int deleteFromPlaylistById(int fd, int id)
+enum playlist_result deleteFromPlaylistById(int id)
 {
-	checkSongId(id);
+	if (!song_id_exists(id))
+		return PLAYLIST_RESULT_NO_SUCH_SONG;
 
-	return deleteFromPlaylist(fd, playlist.idToPosition[id]);
+	return deleteFromPlaylist(playlist.idToPosition[id]);
 }
 
 void deleteASongFromPlaylist(Song * song)
@@ -861,7 +840,7 @@ void deleteASongFromPlaylist(Song * song)
 
 	for (i = 0; i < playlist.length; i++) {
 		if (song == playlist.songs[i]) {
-			deleteFromPlaylist(STDERR_FILENO, i);
+			deleteFromPlaylist(i);
 		}
 	}
 }
@@ -907,7 +886,7 @@ static void play_order_num(int order_num, float seek_time)
 		playlist.current = order_num;
 }
 
-int playPlaylist(int fd, int song, int stopOnError)
+enum playlist_result playPlaylist(int song, int stopOnError)
 {
 	int i = song;
 
@@ -917,11 +896,11 @@ int playPlaylist(int fd, int song, int stopOnError)
 
 	if (song == -1) {
 		if (playlist.length == 0)
-			return 0;
+			return PLAYLIST_RESULT_SUCCESS;
 
 		if (playlist_state == PLAYLIST_STATE_PLAY) {
 			ob_trigger_action(OB_ACTION_PAUSE_UNSET);
-			return 0;
+			return PLAYLIST_RESULT_SUCCESS;
 		}
 		if (playlist.current >= 0 && playlist.current < playlist.length) {
 			i = playlist.current;
@@ -929,9 +908,7 @@ int playPlaylist(int fd, int song, int stopOnError)
 			i = 0;
 		}
 	} else if (song < 0 || song >= playlist.length) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", song);
-		return -1;
+		return PLAYLIST_RESULT_BAD_RANGE;
 	}
 
 	if (playlist.random) {
@@ -953,18 +930,19 @@ int playPlaylist(int fd, int song, int stopOnError)
 	ERROR(__FILE__ ": %d current:%d\n", __LINE__, playlist.current);
 	ob_trigger_action(OB_ACTION_PAUSE_UNSET);
 	play_order_num(i, 0);
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-int playPlaylistById(int fd, int id, int stopOnError)
+enum playlist_result playPlaylistById(int id, int stopOnError)
 {
 	if (id == -1) {
-		return playPlaylist(fd, id, stopOnError);
+		return playPlaylist(id, stopOnError);
 	}
 
-	checkSongId(id);
+	if (!song_id_exists(id))
+		return PLAYLIST_RESULT_NO_SUCH_SONG;
 
-	return playPlaylist(fd, playlist.idToPosition[id], stopOnError);
+	return playPlaylist(playlist.idToPosition[id], stopOnError);
 }
 
 /* This is used when we stream data out to shout while playing static files */
@@ -1051,7 +1029,7 @@ void setPlaylistRepeatStatus(int status)
 	playlist.repeat = status;
 }
 
-int moveSongInPlaylist(int fd, int from, int to)
+enum playlist_result moveSongInPlaylist(int from, int to)
 {
 	int i;
 	Song *tmpSong;
@@ -1059,21 +1037,15 @@ int moveSongInPlaylist(int fd, int from, int to)
 	int currentSong;
 	int queued_is_current = (playlist.queued == playlist.current);
 
-	if (from < 0 || from >= playlist.length) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", from);
-		return -1;
-	}
+	if (from < 0 || from >= playlist.length)
+		return PLAYLIST_RESULT_BAD_RANGE;
 
 	if ((to >= 0 && to >= playlist.length) ||
-	    (to < 0 && abs(to) > playlist.length)) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", to);
-		return -1;
-	}
+	    (to < 0 && abs(to) > playlist.length))
+		return PLAYLIST_RESULT_BAD_RANGE;
 
 	if (from == to) /* no-op */
-		return 0;
+		return PLAYLIST_RESULT_SUCCESS;
 
 	/*
 	 * (to < 0) => move to offset from current song
@@ -1083,7 +1055,7 @@ int moveSongInPlaylist(int fd, int from, int to)
 	if (to < 0 && playlist.current >= 0) {
 		if (currentSong == from)
 			/* no-op, can't be moved to offset of itself */
-			return 0;
+			return PLAYLIST_RESULT_SUCCESS;
 		to = (currentSong + abs(to)) % playlist.length;
 	}
 
@@ -1138,14 +1110,15 @@ int moveSongInPlaylist(int fd, int from, int to)
 	queueNextSongInPlaylist();
 	incrPlaylistVersion();
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-int moveSongInPlaylistById(int fd, int id1, int to)
+enum playlist_result moveSongInPlaylistById(int id1, int to)
 {
-	checkSongId(id1);
+	if (!song_id_exists(id1))
+		return PLAYLIST_RESULT_NO_SUCH_SONG;
 
-	return moveSongInPlaylist(fd, playlist.idToPosition[id1], to);
+	return moveSongInPlaylist(playlist.idToPosition[id1], to);
 }
 
 static void orderPlaylist(void)
@@ -1254,7 +1227,7 @@ void previousSongInPlaylist(void)
 	play_order_num(prev_order_num, 0);
 }
 
-void shufflePlaylist(mpd_unused int fd)
+void shufflePlaylist(void)
 {
 	int i;
 	int ri;
@@ -1293,50 +1266,39 @@ void shufflePlaylist(mpd_unused int fd)
 	}
 }
 
-int deletePlaylist(int fd, const char *utf8file)
+enum playlist_result deletePlaylist(const char *utf8file)
 {
 	char path_max_tmp[MPD_PATH_MAX];
 
 	utf8_to_fs_playlist_path(path_max_tmp, utf8file);
 
-	if (!isPlaylist(path_max_tmp)) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "playlist \"%s\" not found", utf8file);
-		return -1;
-	}
+	if (!isPlaylist(path_max_tmp))
+		return PLAYLIST_RESULT_NO_SUCH_LIST;
 
-	if (unlink(path_max_tmp) < 0) {
-		commandError(fd, ACK_ERROR_SYSTEM,
-			     "problems deleting file");
-		return -1;
-	}
+	if (unlink(path_max_tmp) < 0)
+		return PLAYLIST_RESULT_ERRNO;
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-int savePlaylist(int fd, const char *utf8file)
+enum playlist_result savePlaylist(const char *utf8file)
 {
 	FILE *fp;
 	int i;
 	struct stat sb;
 	char path_max_tmp[MPD_PATH_MAX];
 
-	if (!valid_playlist_name(fd, utf8file))
-		return -1;
+	if (!is_valid_playlist_name(utf8file))
+		return PLAYLIST_RESULT_BAD_NAME;
 
 	utf8_to_fs_playlist_path(path_max_tmp, utf8file);
-	if (!stat(path_max_tmp, &sb)) {
-		commandError(fd, ACK_ERROR_EXIST, "a file or directory already "
-			     "exists with the name \"%s\"", utf8file);
-		return -1;
-	}
+	if (!stat(path_max_tmp, &sb))
+		return PLAYLIST_RESULT_LIST_EXISTS;
 
 	while (!(fp = fopen(path_max_tmp, "w")) && errno == EINTR);
 
-	if (fp == NULL) {
-		commandError(fd, ACK_ERROR_SYSTEM, "failed to create file");
-		return -1;
-	}
+	if (fp == NULL)
+		return PLAYLIST_RESULT_ERRNO;
 
 	for (i = 0; i < playlist.length; i++) {
 		char tmp[MPD_PATH_MAX];
@@ -1353,7 +1315,7 @@ int savePlaylist(int fd, const char *utf8file)
 
 	while (fclose(fp) && errno == EINTR) ;
 
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
 int getPlaylistCurrentSong(void)
@@ -1380,16 +1342,13 @@ int getPlaylistLength(void)
  * This command will always return 0 regardless of whether or
  * not the seek succeeded (it's always been the case, apparently)
  */
-int seekSongInPlaylist(int fd, int song, float seek_time)
+enum playlist_result seekSongInPlaylist(int song, float seek_time)
 {
 	int i = song;
 	char path[MPD_PATH_MAX];
 
-	if (song < 0 || song >= playlist.length) {
-		commandError(fd, ACK_ERROR_NO_EXIST,
-			     "song doesn't exist: \"%i\"", song);
-		return -1;
-	}
+	if (song < 0 || song >= playlist.length)
+		return PLAYLIST_RESULT_BAD_RANGE;
 
 	if (playlist.random)
 		for (i = 0; song != playlist.order[i]; i++) ;
@@ -1402,7 +1361,7 @@ int seekSongInPlaylist(int fd, int song, float seek_time)
 	    (playlist.current == i && playlist.queued == i)) {
 		dc_trigger_action(DC_ACTION_SEEK, seek_time);
 		if (dc.seek_where != DC_SEEK_MISMATCH)
-			return 0;
+			return PLAYLIST_RESULT_SUCCESS;
 		/*
 		 * if near end of decoding can cause seek to fail (since we're
 		 * already on another song) (leading to DC_SEEK_MISMATCH),
@@ -1412,14 +1371,15 @@ int seekSongInPlaylist(int fd, int song, float seek_time)
 
 	DEBUG("playlist: seek %i:\"%s\"\n", i, get_song_url(path, song_at(i)));
 	play_order_num(i, seek_time);
-	return 0;
+	return PLAYLIST_RESULT_SUCCESS;
 }
 
-int seekSongInPlaylistById(int fd, int id, float seek_time)
+enum playlist_result seekSongInPlaylistById(int id, float seek_time)
 {
-	checkSongId(id);
+	if (!song_id_exists(id))
+		return PLAYLIST_RESULT_NO_SUCH_SONG;
 
-	return seekSongInPlaylist(fd, playlist.idToPosition[id], seek_time);
+	return seekSongInPlaylist(playlist.idToPosition[id], seek_time);
 }
 
 int getPlaylistSongId(int song)
@@ -1470,7 +1430,7 @@ int loadPlaylist(int fd, const char *utf8file)
 	node = list->firstNode;
 	while (node != NULL) {
 		char *temp = node->data;
-		if ((addToPlaylist(STDERR_FILENO, temp, NULL)) < 0) {
+		if ((addToPlaylist(temp, NULL)) != PLAYLIST_RESULT_SUCCESS) {
 			/* for windows compatibility, convert slashes */
 			char *temp2 = xstrdup(temp);
 			char *p = temp2;
@@ -1479,7 +1439,7 @@ int loadPlaylist(int fd, const char *utf8file)
 					*p = '/';
 				p++;
 			}
-			if ((addToPlaylist(STDERR_FILENO, temp2, NULL)) < 0) {
+			if ((addToPlaylist(temp, NULL)) != PLAYLIST_RESULT_SUCCESS) {
 				commandError(fd, ACK_ERROR_PLAYLIST_LOAD,
 							"can't add file \"%s\"", temp2);
 			}
diff --git a/src/playlist.h b/src/playlist.h
index 3afe33da0..11ec63e9e 100644
--- a/src/playlist.h
+++ b/src/playlist.h
@@ -24,6 +24,18 @@
 #define PLAYLIST_FILE_SUFFIX 	"m3u"
 #define PLAYLIST_COMMENT	'#'
 
+enum playlist_result {
+	PLAYLIST_RESULT_SUCCESS,
+	PLAYLIST_RESULT_ERRNO,
+	PLAYLIST_RESULT_NO_SUCH_SONG,
+	PLAYLIST_RESULT_NO_SUCH_LIST,
+	PLAYLIST_RESULT_LIST_EXISTS,
+	PLAYLIST_RESULT_BAD_NAME,
+	PLAYLIST_RESULT_BAD_RANGE,
+	PLAYLIST_RESULT_NOT_PLAYING,
+	PLAYLIST_RESULT_TOO_LARGE
+};
+
 extern int playlist_saveAbsolutePaths;
 
 extern int playlist_max_length;
@@ -40,21 +52,21 @@ void clearPlaylist(void);
 
 int clearStoredPlaylist(int fd, const char *utf8file);
 
-int addToPlaylist(int fd, const char *file, int *added_id);
+enum playlist_result addToPlaylist(const char *file, int *added_id);
 
 int addToStoredPlaylist(int fd, const char *file, const char *utf8file);
 
-int addSongToPlaylist(int fd, Song * song, int *added_id);
+enum playlist_result addSongToPlaylist(Song * song, int *added_id);
 
 void showPlaylist(int fd);
 
-int deleteFromPlaylist(int fd, int song);
+enum playlist_result deleteFromPlaylist(int song);
 
-int deleteFromPlaylistById(int fd, int song);
+enum playlist_result deleteFromPlaylistById(int song);
 
-int playlistInfo(int fd, int song);
+enum playlist_result playlistInfo(int fd, int song);
 
-int playlistId(int fd, int song);
+enum playlist_result playlistId(int fd, int song);
 
 Song *playlist_queued_song(void);
 
@@ -64,9 +76,9 @@ int playlist_playing(void);
 
 void stopPlaylist(void);
 
-int playPlaylist(int fd, int song, int stopOnError);
+enum playlist_result playPlaylist(int song, int stopOnError);
 
-int playPlaylistById(int fd, int song, int stopOnError);
+enum playlist_result playPlaylistById(int song, int stopOnError);
 
 void nextSongInPlaylist(void);
 
@@ -74,23 +86,21 @@ void syncPlayerAndPlaylist(void);
 
 void previousSongInPlaylist(void);
 
-void shufflePlaylist(int fd);
-
-int savePlaylist(int fd, const char *utf8file);
+void shufflePlaylist(void);
 
-int deletePlaylist(int fd, const char *utf8file);
+enum playlist_result savePlaylist(const char *utf8file);
 
-int deletePlaylistById(int fd, const char *utf8file);
+enum playlist_result deletePlaylist(const char *utf8file);
 
 void deleteASongFromPlaylist(Song * song);
 
-int moveSongInPlaylist(int fd, int from, int to);
+enum playlist_result moveSongInPlaylist(int from, int to);
 
-int moveSongInPlaylistById(int fd, int id, int to);
+enum playlist_result moveSongInPlaylistById(int id, int to);
 
-int swapSongsInPlaylist(int fd, int song1, int song2);
+enum playlist_result swapSongsInPlaylist(int song1, int song2);
 
-int swapSongsInPlaylistById(int fd, int id1, int id2);
+enum playlist_result swapSongsInPlaylistById(int id1, int id2);
 
 int loadPlaylist(int fd, const char *utf8file);
 
@@ -110,9 +120,9 @@ int getPlaylistLength(void);
 
 unsigned long getPlaylistVersion(void);
 
-int seekSongInPlaylist(int fd, int song, float seek_time);
+enum playlist_result seekSongInPlaylist(int song, float seek_time);
 
-int seekSongInPlaylistById(int fd, int id, float seek_time);
+enum playlist_result seekSongInPlaylistById(int id, float seek_time);
 
 void playlistVersionChange(void);