mpdclient: rewrite the "fancy add" code

This is a trick to keep playlist adds cheap: ncmpc tries to predict
the new playlist.

diff --git a/src/mpdclient.c b/src/mpdclient.c
index 864d09189b6eb59e787700b2ebf2bff5281c750f..94bf4f1667962052f1bc9f233de05e7e30702fae 100644 (file)
--- a/src/mpdclient.c
+++ b/src/mpdclient.c
@@ -32,7 +32,6 @@
 #include <time.h>
 #include <string.h>
 
-#undef  ENABLE_FANCY_PLAYLIST_MANAGMENT_CMD_ADD /* broken with song id's */
 #define ENABLE_FANCY_PLAYLIST_MANAGMENT_CMD_DELETE
 #define ENABLE_FANCY_PLAYLIST_MANAGMENT_CMD_MOVE
 
@@ -400,30 +399,64 @@ mpdclient_cmd_add_path(struct mpdclient *c, const gchar *path_utf8)
 gint
 mpdclient_cmd_add(struct mpdclient *c, const struct mpd_song *song)
 {
-       gint retval = 0;
+       struct mpd_status *status;
+       struct mpd_song *new_song;
 
        assert(c != NULL);
        assert(song != NULL);
 
-       if (MPD_ERROR(c))
+       if (MPD_ERROR(c) || c->status == NULL)
                return -1;
 
-       /* send the add command to mpd */
-       mpd_send_add(c->connection, mpd_song_get_uri(song));
-       if( (retval=mpdclient_finish_command(c)) )
-               return retval;
+       /* send the add command to mpd; at the same time, get the new
+          status (to verify the new playlist id) and the last song
+          (we hope that's the song we just added) */
+
+       if (!mpd_command_list_begin(c->connection, true) ||
+           !mpd_send_add(c->connection, mpd_song_get_uri(song)) ||
+           !mpd_send_status(c->connection) ||
+           !mpd_send_get_queue_song_pos(c->connection,
+                                        playlist_length(&c->playlist)) ||
+           !mpd_command_list_end(c->connection) ||
+           !mpd_response_next(c->connection))
+               return mpdclient_handle_error(c);
 
-#ifdef ENABLE_FANCY_PLAYLIST_MANAGMENT_CMD_ADD
-       /* add the song to playlist */
-       playlist_append(&c->playlist, song);
+       c->events |= MPD_IDLE_PLAYLIST;
 
-       /* increment the playlist id, so we don't retrieve a new playlist */
-       c->playlist.version++;
+       status = mpd_recv_status(c->connection);
+       if (status != NULL) {
+               if (c->status != NULL)
+                       mpd_status_free(c->status);
+               c->status = status;
+       }
 
-       c->events |= MPD_IDLE_PLAYLIST;
-#endif
+       if (!mpd_response_next(c->connection))
+               return mpdclient_handle_error(c);
 
-       return 0;
+       new_song = mpd_recv_song(c->connection);
+       if (!mpd_response_finish(c->connection) || new_song == NULL) {
+               if (new_song != NULL)
+                       mpd_song_free(new_song);
+
+               return mpd_connection_clear_error(c->connection)
+                       ? 0 : mpdclient_handle_error(c);
+       }
+
+       if (mpd_status_get_queue_length(status) == playlist_length(&c->playlist) + 1 &&
+           mpd_status_get_queue_version(status) == c->playlist.version + 1) {
+               /* the cheap route: match on the new playlist length
+                  and its version, we can keep our local playlist
+                  copy in sync */
+               c->playlist.version = mpd_status_get_queue_version(status);
+
+               /* the song we just received has the correct id;
+                  append it to the local playlist */
+               playlist_append(&c->playlist, new_song);
+       }
+
+       mpd_song_free(new_song);
+
+       return -0;
 }
 
 gint