Initial import of missing tracks plugin

This plugin adds a new command, ``missing`` or ``miss``, which finds
and lists, for every album in your collection, which tracks are
missing.

beetsplug/missing.py

@@ -0,0 +1,132 @@
+# This file is not part of beets.
+# Copyright 2013, Pedro Silva.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+
+'''list missing tracks
+'''
+import logging
+
+from beets.autotag import hooks
+from beets.library import Item
+from beets.plugins import BeetsPlugin
+from beets.ui import decargs, print_obj, Subcommand
+
+plugin = 'missing'
+log = logging.getLogger('beets')
+
+
+def _missing(album, lib=None):
+    '''Query MusicBrainz to determine items missing from `album`,
+     caching them in `lib` to avoid further queries.
+    '''
+    item_paths = filter(None, map(lambda i: i.path, album.items()))
+    item_mbids = map(lambda x: x.mb_trackid,
+                     filter(lambda i: i.path is not None, album.items()))
+
+    if len(item_paths) < album.tracktotal:
+        # fetch missing items
+        # TODO: Implement caching that without breaking other stuff
+        album_info = hooks._album_for_id(album.mb_albumid)
+        for track_info in getattr(album_info, 'tracks', []):
+            if track_info.track_id not in item_mbids:
+                item = _item(track_info, album_info, album.id)
+                log.debug('{}: track {} in album {}'
+                          .format(plugin,
+                                  track_info.track_id,
+                                  album_info.album_id))
+                yield item
+
+
+def _format(song):
+    '''
+    Format unicode-encoded representation of a pygrooveshark song.
+    '''
+    return " - ".join([song.artist.name.encode('utf-8'),
+                       song.album.name.encode('utf-8'),
+                       song.name.encode('utf-8')])
+
+
+def _item(track_info, album_info, album_id):
+    '''Build and return `item` from `track_info` and `album info`
+    objects. `item` is missing what fields cannot be obtained from
+    MusicBrainz alone (encoder, rg_track_gain, rg_track_peak,
+    rg_album_gain, rg_album_peak, original_year, original_month,
+    original_day, length, bitrate, format, samplerate, bitdepth,
+    channels, mtime.)
+    '''
+    t = track_info
+    a = album_info
+
+    return Item({'album_id': album_id,
+                 'album':              a.album,
+                 'albumartist':        a.artist,
+                 'albumartist_credit': a.artist_credit,
+                 'albumartist_sort':   a.artist_sort,
+                 'albumdisambig':      a.albumdisambig,
+                 'albumstatus':        a.albumstatus,
+                 'albumtype':          a.albumtype,
+                 'artist':             t.artist,
+                 'artist_credit':      t.artist_credit,
+                 'artist_sort':        t.artist_sort,
+                 'asin':               a.asin,
+                 'catalognum':         a.catalognum,
+                 'comp':               a.va,
+                 'country':            a.country,
+                 'day':                a.day,
+                 'disc':               t.medium,
+                 'disctitle':          t.disctitle,
+                 'disctotal':          a.mediums,
+                 'label':              a.label,
+                 'language':           a.language,
+                 'length':             t.length,
+                 'mb_albumid':         a.album_id,
+                 'mb_artistid':        t.artist_id,
+                 'mb_releasegroupid':  a.releasegroup_id,
+                 'mb_trackid':         t.track_id,
+                 'media':              a.media,
+                 'month':              a.month,
+                 'script':             a.script,
+                 'title':              t.title,
+                 'track':              t.index,
+                 'tracktotal':         len(a.tracks),
+                 'year':               a.year})
+
+
+class MissingPlugin(BeetsPlugin):
+    '''List missing tracks
+    '''
+    def __init__(self):
+        super(MissingPlugin, self).__init__()
+
+        self.config.add({'format': None})
+
+        self._command = Subcommand('missing',
+                                   help=__doc__,
+                                   aliases=['miss'])
+
+        self._command.parser.add_option('-f', '--format', dest='format',
+                                        action='store', type='string',
+                                        help='print with custom FORMAT',
+                                        metavar='FORMAT')
+
+    def commands(self):
+        def _miss(lib, opts, args):
+            self.config.set_args(opts)
+            fmt = self.config['format'].get()
+
+            for album in lib.albums(decargs(args)):
+                for item in _missing(album, lib):
+                    print_obj(item, lib, fmt=fmt)
+
+        self._command.func = _miss
+        return [self._command]