Add importmtimes plugin for preserving file mtimes during copy imports.

File modification times are stored as item.mtime, item.added and
album.added.

beetsplug/importmtimes.py

@@ -0,0 +1,77 @@
+"""Preserve file modification times during copy imports.
+
+File modification times are also stored in the `added` field.
+"""
+
+from __future__ import unicode_literals, absolute_import, print_function
+
+import logging, os
+
+from beets import config
+from beets import util
+from beets.plugins import BeetsPlugin
+
+log = logging.getLogger('beets')
+
+class ImportMtimesPlugin(BeetsPlugin):
+    pass
+
+@ImportMtimesPlugin.listen('import_task_start')
+def check_config(task, session):
+    if not config['import']['copy']:
+        raise ValueError('The importmtimes plugin can only be used for copy'
+                         ' imports')
+
+def copy_mtime(source_path, dest_path):
+    """Copy the file mtime from the source path to the destination path.
+    """
+    source_stat = os.stat(util.syspath(source_path))
+    dest_stat = os.stat(util.syspath(dest_path))
+    os.utime(util.syspath(dest_path),
+             (dest_stat.st_atime, source_stat.st_mtime))
+
+# key: item path in the library
+# value: file outside the library from which the item was imported
+item_source_paths = dict()
+
+def preserve_mtime(item):
+    """Preserve the file modification time of an imported item by copying the
+    mtime from the file that the item is copied from.
+    """
+    source_path = item_source_paths.get(item.path)
+    if source_path is None:
+        log.warn("No import source path found for item "
+                 + util.displayable_path(item.path))
+        return
+
+    copy_mtime(source_path, item.path)
+    item.mtime = os.path.getmtime(util.syspath(item.path))
+    del item_source_paths[item.path]
+
+@ImportMtimesPlugin.listen('item_copied')
+def record_import_source_path(item, source, destination):
+    """Record which file an imported item is copied from.
+    """
+    if (source == destination):
+        return
+
+    item_source_paths[destination] = source
+    log.debug('Recorded item source path "%s" <- "%s"',
+              util.displayable_path(destination),
+              util.displayable_path(source))
+
+@ImportMtimesPlugin.listen('album_imported')
+def update_album_times(lib, album):
+    for item in album.items():
+        preserve_mtime(item)
+        item.store()
+
+    item_mtimes = (item.mtime for item in album.items() if item.mtime > 0)
+    album.added = min(item_mtimes)
+    album.store()
+
+@ImportMtimesPlugin.listen('item_imported')
+def update_item_times(lib, item):
+    preserve_mtime(item)
+    item.added = item.mtime
+    item.store()

docs/plugins/importmtimes.rst

@@ -0,0 +1,24 @@
+ImportMtimes Plugin
+===================
+
+The ``importmtimes`` plugin is useful when an existing collection is imported
+and the time when albums and items were added should be preserved.
+
+The :abbr:`mtime (modification time)` of files that are imported into the
+library are assumed to represent the time when the items were originally
+added.
+
+File modification times are imported as follows:
+
+* For all items, ``item.mtime`` is set to the mtime of the file
+  from which the item is imported from.
+* For singleton items with no album, ``item.added`` is set to ``item.mtime``
+  during import.
+* For items that are part of an album, ``album.added`` and ``item.added`` is
+  set to the oldest mtime of the album items.
+* The mtime of an album's directory is ignored.
+
+There are no configuration options for this plugin.
+
+This plugin can only be used if Beets is :doc:`configured </reference/config>` to copy
+files on import.

docs/plugins/index.rst

@@ -59,6 +59,7 @@ by typing ``beet version``.
    ftintitle
    keyfinder
    bucket
+   importmtimes
 
 Autotagger Extensions
 ---------------------
@@ -91,6 +92,8 @@ Metadata
   statistics (last_played, play_count, skip_count, rating).
 * :doc:`keyfinder`: Use the `KeyFinder`_ program to detect the musical
   key from the audio.
+* :doc:`importmtimes`: Preserve file modification times and use them as values
+  for the `added` and `mtime` fields in the database.
 
 .. _Acoustic Attributes: http://developer.echonest.com/acoustic-attributes.html
 .. _the Echo Nest: http://www.echonest.com