...

src/calibre/devices/mtp/base.py

@@ -7,8 +7,17 @@ __license__   = 'GPL v3'
 __copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
+from functools import wraps
+
 from calibre.devices.interface import DevicePlugin
 
+def synchronous(func):
+    @wraps(func)
+    def synchronizer(self, *args, **kwargs):
+        with self.lock:
+            return func(self, *args, **kwargs)
+    return synchronizer
+
 class MTPDeviceBase(DevicePlugin):
     name = 'SmartDevice App Interface'
     gui_name = _('MTP Device')

src/calibre/devices/mtp/unix/driver.py

@@ -9,23 +9,15 @@ __docformat__ = 'restructuredtext en'
 
 import time, operator
 from threading import RLock
-from functools import wraps
 from itertools import chain
 from collections import deque, OrderedDict
 from io import BytesIO
 
 from calibre import prints
 from calibre.devices.errors import OpenFailed
-from calibre.devices.mtp.base import MTPDeviceBase
+from calibre.devices.mtp.base import MTPDeviceBase, synchronous
 from calibre.devices.mtp.unix.detect import MTPDetect
 
-def synchronous(func):
-    @wraps(func)
-    def synchronizer(self, *args, **kwargs):
-        with self.lock:
-            return func(self, *args, **kwargs)
-    return synchronizer
-
 class FilesystemCache(object):
 
     def __init__(self, files, folders):