Make core_queue available for backends

mopidy/backends/__init__.py

@@ -9,12 +9,17 @@ from mopidy.models import Playlist
 logger = logging.getLogger('backends.base')
 
 class BaseBackend(object):
-    def __init__(self, mixer=None):
+    def __init__(self, core_queue=None, mixer=None):
+        self.core_queue = core_queue
         if mixer is not None:
             self.mixer = mixer
         else:
             self.mixer = get_class(settings.MIXER)()
 
+    #: A :class:`multiprocessing.Queue` which can be used by e.g. library
+    #: callbacks to send messages to the core.
+    core_queue = None
+
     #: The current playlist controller. An instance of
     #: :class:`BaseCurrentPlaylistController`.
     current_playlist = None

mopidy/core.py

@@ -11,7 +11,7 @@ class CoreProcess(multiprocessing.Process):
         self.core_queue = core_queue
 
     def run(self):
-        backend = get_class(settings.BACKENDS[0])()
+        backend = get_class(settings.BACKENDS[0])(core_queue=self.core_queue)
         frontend = get_class(settings.FRONTEND)(backend=backend)
         while True:
             message = self.core_queue.get()