add track mapping to album_distance plugin method

beets/autotag/match.py

@@ -289,7 +289,7 @@ def distance(items, album_info, mapping):
         dist_max += UNMATCHED_WEIGHT
 
     # Plugin distances.
-    plugin_d, plugin_dm = plugins.album_distance(items, album_info)
+    plugin_d, plugin_dm = plugins.album_distance(items, album_info, mapping)
     dist += plugin_d
     dist_max += plugin_dm
 

beets/plugins.py

@@ -57,7 +57,7 @@ class BeetsPlugin(object):
         """
         return 0.0, 0.0
 
-    def album_distance(self, items, info):
+    def album_distance(self, items, album_info, mapping):
         """Should return a (distance, distance_max) pair to be added
         to the distance value for every album-level comparison.
         """
@@ -211,12 +211,12 @@ def track_distance(item, info):
         dist_max += dm
     return dist, dist_max
 
-def album_distance(items, info):
+def album_distance(items, album_info, mapping):
     """Returns the album distance calculated by plugins."""
     dist = 0.0
     dist_max = 0.0
     for plugin in find_plugins():
-        d, dm = plugin.album_distance(items, info)
+        d, dm = plugin.album_distance(items, album_info, mapping)
         dist += d
         dist_max += dm
     return dist, dist_max

docs/changelog.rst

@@ -6,6 +6,7 @@ Changelog
 
 * :doc:`/plugins/fetchart`: Fix a bug where cover art filenames could lack
   a ``.jpg`` extension.
+* Add the track mapping dictionary to the ``album_distance`` plugin function.
 
 1.0b15 (July 26, 2012)
 ----------------------

docs/plugins/writing.rst

@@ -167,14 +167,15 @@ methods on the plugin class:
 
 * ``track_distance(self, item, info)``: adds a component to the distance
   function (i.e., the similarity metric) for individual tracks. ``item`` is the
-  track to be matched (and Item object) and ``info`` is the MusicBrainz track
-  entry that is proposed as a match. Should return a ``(dist, dist_max)`` pair
+  track to be matched (an Item object) and ``info`` is the TrackInfo object
+  that is proposed as a match. Should return a ``(dist, dist_max)`` pair
   of floats indicating the distance.
 
-* ``album_distance(self, items, info)``: like the above, but compares a list of
-  items (representing an album) to an album-level MusicBrainz entry. Should
-  only consider album-level metadata (e.g., the artist name and album title) and
-  should not duplicate the factors considered by ``track_distance``.
+* ``album_distance(self, items, album_info, mapping)``: like the above, but
+  compares a list of items (representing an album) to an album-level MusicBrainz
+  entry. ``items`` is a list of Item objects; ``album_info`` is an AlbumInfo
+  object; and ``mapping`` is a dictionary that maps Items to their corresponding
+  TrackInfo objects.
 
 * ``candidates(self, items)``: given a list of items comprised by an album to be
   matched, return a list of ``AlbumInfo`` objects for candidate albums to be