Port calibredb backup_metadata

src/calibre/db/cli/cmd_backup_metadata.py

@@ -4,19 +4,66 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-readonly = False
+from calibre import prints
+
+readonly = True
 version = 0  # change this if you change signature of implementation()
+no_remote = True
 
 
 def implementation(db, notify_changes, *args):
-    is_remote = notify_changes is not None
-    is_remote
+    raise NotImplementedError()
 
 
 def option_parser(get_parser, args):
-    pass
+    parser = get_parser(
+        _(
+            '''\
+%prog backup_metadata [options]
+
+Backup the metadata stored in the database into individual OPF files in each
+books directory. This normally happens automatically, but you can run this
+command to force re-generation of the OPF files, with the --all option.
+
+Note that there is normally no need to do this, as the OPF files are backed up
+automatically, every time metadata is changed.
+'''
+        )
+    )
+    parser.add_option(
+        '--all',
+        default=False,
+        action='store_true',
+        help=_(
+            'Normally, this command only operates on books that have'
+            ' out of date OPF files. This option makes it operate on all'
+            ' books.'
+        )
+    )
+    return parser
+
+
+class BackupProgress(object):
+
+    def __init__(self):
+        self.total = 0
+        self.count = 0
+
+    def __call__(self, book_id, mi, ok):
+        if mi is True:
+            self.total = book_id
+        else:
+            self.count += 1
+            prints(
+                u'%.1f%% %s - %s' % ((self.count * 100) / float(self.total), book_id,
+                                     getattr(mi, 'title', 'Unknown'))
+            )
 
 
 def main(opts, args, dbctx):
-    raise NotImplementedError('TODO: implement this')
+    db = dbctx.db
+    book_ids = None
+    if opts.all:
+        book_ids = db.all_ids()
+    db.dump_metadata(book_ids=book_ids, callback=BackupProgress())
     return 0

src/calibre/db/cli/main.py

@@ -22,8 +22,8 @@ COMMANDS = (
     'list', 'add', 'remove', 'add_format', 'remove_format', 'show_metadata',
     'set_metadata', 'export', 'catalog', 'saved_searches', 'add_custom_column',
     'custom_columns', 'remove_custom_column', 'set_custom', 'restore_database',
-    'check_library',
-    # 'list_categories', 'backup_metadata', 'clone', 'embed_metadata', 'search'
+    'check_library', 'list_categories', 'backup_metadata',
+    # 'clone', 'embed_metadata', 'search'
 )