mpdclient: rewrite the "fancy delete" code

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

diff --git a/src/mpdclient.c b/src/mpdclient.c
index 94bf4f1667962052f1bc9f233de05e7e30702fae..33f50184a90e52062d5482abbbd5ab75ff795cca 100644 (file)
--- a/src/mpdclient.c
+++ b/src/mpdclient.c
@@ -32,7 +32,6 @@
 #include <time.h>
 #include <string.h>
 
-#define ENABLE_FANCY_PLAYLIST_MANAGMENT_CMD_DELETE
 #define ENABLE_FANCY_PLAYLIST_MANAGMENT_CMD_MOVE
 
 #define BUFSIZE 1024
@@ -462,10 +461,10 @@ mpdclient_cmd_add(struct mpdclient *c, const struct mpd_song *song)
 gint
 mpdclient_cmd_delete(struct mpdclient *c, gint idx)
 {
-       gint retval = 0;
-       struct mpd_song *song;
+       const struct mpd_song *song;
+       struct mpd_status *status;
 
-       if (MPD_ERROR(c))
+       if (MPD_ERROR(c) || c->status == NULL)
                return -1;
 
        if (idx < 0 || (guint)idx >= playlist_length(&c->playlist))
@@ -473,26 +472,41 @@ mpdclient_cmd_delete(struct mpdclient *c, gint idx)
 
        song = playlist_get(&c->playlist, idx);
 
-       /* send the delete command to mpd */
-       mpd_send_delete_id(c->connection, mpd_song_get_id(song));
-       if( (retval=mpdclient_finish_command(c)) )
-               return retval;
-
-#ifdef ENABLE_FANCY_PLAYLIST_MANAGMENT_CMD_DELETE
-       /* increment the playlist id, so we don't retrieve a new playlist */
-       c->playlist.version++;
+       /* send the delete command to mpd; at the same time, get the
+          new status (to verify the playlist id) */
 
-       /* remove the song from the playlist */
-       playlist_remove_reuse(&c->playlist, idx);
+       if (!mpd_command_list_begin(c->connection, false) ||
+           !mpd_send_delete_id(c->connection, mpd_song_get_id(song)) ||
+           !mpd_send_status(c->connection) ||
+           !mpd_command_list_end(c->connection))
+               return mpdclient_handle_error(c);
 
        c->events |= MPD_IDLE_PLAYLIST;
 
-       /* remove references to the song */
-       if (c->song == song)
-               c->song = NULL;
+       status = mpd_recv_status(c->connection);
+       if (status != NULL) {
+               if (c->status != NULL)
+                       mpd_status_free(c->status);
+               c->status = status;
+       }
 
-       mpd_song_free(song);
-#endif
+       if (!mpd_response_finish(c->connection))
+               return 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);
+
+               /* remove the song from the local playlist */
+               playlist_remove(&c->playlist, idx);
+
+               /* remove references to the song */
+               if (c->song == song)
+                       c->song = NULL;
+       }
 
        return 0;
 }