[gnome-music] albumArtCache: Fix full retrieve of song items

[Vadim Rutkovsky <vrutkovsky src gnome org>]

commit 82ae2ddeec5a7db26a7f311fd9a924010b4edbed
Author: Arnel Borja <arnelborja src gnome org>
Date:   Mon Apr 28 19:55:14 2014 +0800

    albumArtCache: Fix full retrieve of song items
    
    Check first if the item is a song before retrieving the item's thumbnail
    with full options. The old code always assumes that the item is an
    album. Then use a different query to retrieve the album if it is a song.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=729102

 gnomemusic/albumArtCache.py |    6 +++---
 gnomemusic/grilo.py         |   11 +++++++++--
 gnomemusic/query.py         |   28 +++++++++++++++++++++++++++-
 3 files changed, 39 insertions(+), 6 deletions(-)
---
diff --git a/gnomemusic/albumArtCache.py b/gnomemusic/albumArtCache.py
index 26a13e4..5e5cf4e 100644
--- a/gnomemusic/albumArtCache.py
+++ b/gnomemusic/albumArtCache.py
@@ -176,8 +176,8 @@ class AlbumArtCache:
         try:
             uri = item.get_thumbnail()
             if uri is None:
-                grilo.get_album_art_for_album_id(item.get_id(), self.album_art_for_album_id_callback,
-                                                 (item, width, height, path, callback, itr, artist, album))
+                grilo.get_album_art_for_item(item, self.album_art_for_item_callback,
+                                             (item, width, height, path, callback, itr, artist, album))
                 return
 
             start_new_thread(self.download_worker,
@@ -186,7 +186,7 @@ class AlbumArtCache:
             logger.warn("Error: %s" % e)
 
     @log
-    def album_art_for_album_id_callback(self, source, param, item, count, data, error):
+    def album_art_for_item_callback(self, source, param, item, count, data, error):
         old_item, width, height, path, callback, itr, artist, album = data
         try:
             uri = item.get_thumbnail()
diff --git a/gnomemusic/grilo.py b/gnomemusic/grilo.py
index fffafe2..7402f7f 100644
--- a/gnomemusic/grilo.py
+++ b/gnomemusic/grilo.py
@@ -197,10 +197,17 @@ class Grilo(GObject.GObject):
         self.tracker.query(query, self.METADATA_KEYS, options, _callback, None)
 
     @log
-    def get_album_art_for_album_id(self, album_id, callback, data=None):
+    def get_album_art_for_item(self, item, callback, data=None):
+        item_id = item.get_id()
+
+        query = None
+        if isinstance(item, Grl.MediaAudio):
+            query = Query.get_album_for_song_id(item_id)
+        else:
+            query = Query.get_album_for_album_id(item_id)
+
         options = self.full_options.copy()
         options.set_count(1)
-        query = Query.get_album_for_id(album_id)
         self.tracker.query(query, self.METADATA_THUMBNAIL_KEYS, options, callback, data)
 
 
diff --git a/gnomemusic/query.py b/gnomemusic/query.py
index fc8b8f3..cfc919d 100644
--- a/gnomemusic/query.py
+++ b/gnomemusic/query.py
@@ -252,7 +252,7 @@ class Query():
         return query
 
     @staticmethod
-    def get_album_for_id(album_id):
+    def get_album_for_album_id(album_id):
         query = """
     SELECT DISTINCT
         rdf:type(?album)
@@ -277,6 +277,32 @@ class Query():
         return query
 
     @staticmethod
+    def get_album_for_song_id(song_id):
+        query = """
+    SELECT DISTINCT
+        rdf:type(?album)
+        tracker:id(?album) AS id
+        (
+            SELECT
+                nmm:artistName(?artist)
+            WHERE {
+                ?album nmm:albumArtist ?artist
+            }
+            LIMIT 1
+        ) AS artist
+        nie:title(?album) AS title
+        nie:title(?album) AS album
+    WHERE {
+        ?song a nmm:MusicPiece ;
+              nmm:musicAlbum ?album .
+        FILTER (
+            tracker:id(?song) = %(song_id)s
+        )
+    }
+    """.replace("\n", " ").strip() % {'song_id': song_id}
+        return query
+
+    @staticmethod
     def get_song_with_url(url):
         query = '''
     SELECT DISTINCT