directory: allow directories with just playlists

Keep those when scanning for empty directories.  The check in
playlist_vector_is_empty() was missing.

NEWS

@@ -2,6 +2,7 @@ ver 0.16.3 (2011/??/??)
 * fix assertion failure in audio format mask parser
 * fix NULL pointer dereference in playlist parser
 * fix playlist files in base music directory
+* database: allow directories with just playlists
 * decoder:
   - ffmpeg: support libavcodec 0.7
 

src/directory.h

@@ -62,7 +62,8 @@ directory_free(struct directory *directory);
 static inline bool
 directory_is_empty(const struct directory *directory)
 {
-	return directory->children.nr == 0 && directory->songs.nr == 0;
+	return directory->children.nr == 0 && directory->songs.nr == 0 &&
+		playlist_vector_is_empty(&directory->playlists);
 }
 
 static inline const char *

src/playlist_vector.h

@@ -51,6 +51,12 @@ playlist_vector_init(struct playlist_vector *pv)
 void
 playlist_vector_deinit(struct playlist_vector *pv);
 
+static inline bool
+playlist_vector_is_empty(const struct playlist_vector *pv)
+{
+	return pv->head == NULL;
+}
+
 struct playlist_metadata *
 playlist_vector_find(struct playlist_vector *pv, const char *name);