Merge branch 'ew/update-thrsafe'

* ew/update-thrsafe:
  directory: serialize song deletes from playlist during update
  directory: use songvec_for_each for iterators
  dbUtils: more cleanups
  song: Add song_print_url_x
  dbUtils/directory: traverseAllIn forEachSong returns -1 on error
  songvec: lock traversals for thread-safe updates/reads
  song: add print_song_info_x for iterators tha pass void *
  songvec: add songvec_for_each iterator
  song: replace printSong* with song_print_*
  Assert if we don't have song or song->url set

1 files changed, 8 insertions, 4 deletions

diff --git a/src/song.h b/src/song.h
index 377a78814..9aa9efa94 100644
--- a/src/song.h
+++ b/src/song.h
@@ -42,17 +42,21 @@ typedef struct _Song {
 
 Song *newSong(const char *url, struct _Directory *parentDir);
 
-void freeSong(Song *);
-
 void freeJustSong(Song *);
 
-int printSongInfo(int fd, Song * song);
+ssize_t song_print_info(Song * song, int fd);
+
+/* like song_print_info, but casts data into an fd first */
+int song_print_info_x(Song * song, void *data);
 
 void readSongInfoIntoList(FILE * fp, struct _Directory *parent);
 
 int updateSongInfo(Song * song);
 
-void printSongUrl(int fd, Song * song);
+ssize_t song_print_url(Song * song, int fd);
+
+/* like song_print_url_x, but casts data into an fd first */
+int song_print_url_x(Song * song, void *data);
 
 /*
  * get_song_url - Returns a path of a song in UTF8-encoded form