[sound-juicer] Fill album composer using track composers

[Christophe Fergeau <teuf src gnome org>]

commit 3b23b8acfcbc109a64b6b8896440777b854a163c
Author: Phillip Wood <phillip wood dunelm org uk>
Date:   Thu Mar 29 15:05:58 2012 +0100

    Fill album composer using track composers
    
    Musicbrainz relations do not provide an album composer. If all the
    tracks have the same or have no composer use the composer and
    composer_sortname from the first track, if they have
    differing composers set the album composer and composer_sortname to
    "Various Composers".
    
    https://bugzilla.gnome.org/show_bug.cgi?id=661646

 libjuicer/sj-metadata-musicbrainz4.c |   38 ++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)
---
diff --git a/libjuicer/sj-metadata-musicbrainz4.c b/libjuicer/sj-metadata-musicbrainz4.c
index 087f79a..29e5bf7 100644
--- a/libjuicer/sj-metadata-musicbrainz4.c
+++ b/libjuicer/sj-metadata-musicbrainz4.c
@@ -228,6 +228,43 @@ fill_relations (Mb4RelationList relations, AlbumDetails *album)
   }
 }
 
+static void
+fill_album_composer (AlbumDetails *album)
+{
+  char *old_composer;
+  GList *l;
+  TrackDetails *track_one; /* The first track on the album */
+  gboolean one_composer = TRUE; /* TRUE if all tracks have the same composer */
+
+  if (album->composer != NULL)
+    return;
+
+  if (album->tracks == NULL)
+    return;
+
+  l = album->tracks;
+  track_one = (TrackDetails*)l->data;
+  old_composer = track_one->composer;
+
+  for (l = l->next; l != NULL; l = l->next) {
+    char *new_composer;
+    TrackDetails *track = (TrackDetails*)l->data;
+    new_composer = track->composer;
+    if (g_strcmp0 (old_composer, new_composer) != 0) {
+      one_composer = FALSE;
+      break;
+    }
+  }
+
+  if (one_composer) {
+    album->composer = g_strdup (track_one->composer);
+    album->composer_sortname = g_strdup (track_one->composer_sortname);
+  } else {
+    album->composer = g_strdup ("Various Composers");
+    album->composer_sortname = g_strdup ("Various Composers");
+  }
+}
+
 typedef void (*RelationForeachFunc)(Mb4Relation relation, gpointer user_data);
 
 static void relationlist_list_foreach_relation(Mb4RelationListList relation_lists,
@@ -426,6 +463,7 @@ make_album_from_release (Mb4ReleaseGroup group,
 
   album->disc_number = mb4_medium_get_position (medium);
   fill_tracks_from_medium (medium, album);
+  fill_album_composer (album);
   fill_relations (mb4_release_get_relationlist (release), album);
 
   sj_mb4_album_details_dump (album);