playlist: Add playlist auto-update functionality

beetsplug/playlist.py

@@ -14,6 +14,7 @@
 
 import os
 import fnmatch
+import tempfile
 import beets
 
 
@@ -86,6 +87,98 @@ class PlaylistPlugin(beets.plugins.BeetsPlugin):
     def __init__(self):
         super(PlaylistPlugin, self).__init__()
         self.config.add({
+            'auto': False,
             'playlist_dir': '.',
             'relative_to': 'library',
         })
+
+        self.playlist_dir = self.config['playlist_dir'].as_filename()
+        self.changes = {}
+
+        if self.config['relative_to'].get() == 'library':
+            self.relative_to = beets.util.bytestring_path(
+                beets.config['directory'].as_filename())
+        elif self.config['relative_to'].get() != 'playlist':
+            print(repr(self.config['relative_to'].get()))
+            self.relative_to = beets.util.bytestring_path(
+                self.config['relative_to'].as_filename())
+        else:
+            self.relative_to = None
+
+        if self.config['auto'].get(bool):
+            self.register_listener('item_moved', self.item_moved)
+            self.register_listener('item_removed', self.item_removed)
+            self.register_listener('cli_exit', self.cli_exit)
+
+    def item_moved(self, item, source, destination):
+        self.changes[source] = destination
+
+    def item_removed(self, item):
+        if not os.path.exists(beets.util.syspath(item.path)):
+            self.changes[item.path] = None
+
+    def cli_exit(self, lib):
+        for playlist in self.find_playlists():
+            self._log.info('Updating playlist: {0}'.format(playlist))
+            base_dir = beets.util.bytestring_path(
+                self.relative_to if self.relative_to
+                else os.path.dirname(playlist)
+            )
+
+            try:
+                self.update_playlist(playlist, base_dir)
+            except beets.util.FilesystemError:
+                self._log.error('Failed to update playlist: {0}'.format(
+                    beets.util.displayable_path(playlist)))
+
+    def find_playlists(self):
+        """Find M3U playlists in the playlist directory."""
+        try:
+            dir_contents = os.listdir(beets.util.syspath(self.playlist_dir))
+        except OSError:
+            self._log.warning('Unable to open playlist directory {0}'.format(
+                beets.util.displayable_path(self.playlist_dir)))
+            return
+
+        for filename in dir_contents:
+            if fnmatch.fnmatch(filename, '*.[mM]3[uU]'):
+                yield os.path.join(self.playlist_dir, filename)
+
+    def update_playlist(self, filename, base_dir):
+        """Find M3U playlists in the specified directory."""
+        changes = 0
+        deletions = 0
+
+        with tempfile.NamedTemporaryFile(mode='w+b') as tempfp:
+            with open(filename, mode='rb') as fp:
+                for line in fp:
+                    original_path = line.rstrip(b'\r\n')
+
+                    # Ensure that path from playlist is absolute
+                    is_relative = not os.path.isabs(beets.util.syspath(line))
+                    if is_relative:
+                        lookup = os.path.join(base_dir, original_path)
+                    else:
+                        lookup = original_path
+
+                    try:
+                        new_path = self.changes[lookup]
+                    except KeyError:
+                        tempfp.write(line)
+                    else:
+                        if new_path is None:
+                            # Item has been deleted
+                            deletions += 1
+                            continue
+
+                        changes += 1
+                        if is_relative:
+                            new_path = os.path.relpath(new_path, base_dir)
+
+                        tempfp.write(line.replace(original_path, new_path))
+            if changes or deletions:
+                self._log.info(
+                    'Updated playlist {0} ({1} changes, {2} deletions)'.format(
+                        filename, changes, deletions))
+                tempfp.flush()
+                beets.util.copy(tempfp.name, filename, replace=True)