song: better handling of existing songs when rereading DB

Don't reallocate existing tags if they haven't changed.
This isn't used as often anymore, but we still take HUP
signals to reread the DB if other processes changed it.

1 files changed, 13 insertions, 4 deletions

diff --git a/src/song.c b/src/song.c
index dc100899a..4f7b2f8bb 100644
--- a/src/song.c
+++ b/src/song.c
@@ -123,11 +123,20 @@ static void insertSongIntoList(struct songvec *sv, Song *newsong)
 			tag_end_add(newsong->tag);
 	} else { /* prevent dupes, just update the existing song info */
 		if (existing->mtime != newsong->mtime) {
-			tag_free(existing->tag);
-			if (newsong->tag)
-				tag_end_add(newsong->tag);
-			existing->tag = newsong->tag;
 			existing->mtime = newsong->mtime;
+			if (tag_equal(existing->tag, newsong->tag)) {
+				if (newsong->tag)
+					tag_free(newsong->tag);
+			} else {
+				struct mpd_tag *old_tag = existing->tag;
+
+				if (newsong->tag)
+					tag_end_add(newsong->tag);
+				existing->tag = newsong->tag;
+				if (old_tag)
+					tag_free(old_tag);
+			}
+			/* prevent tag_free in freeJustSong */
 			newsong->tag = NULL;
 		}
 		freeJustSong(newsong);