Backend API: Add optional argument 'output_connection' to BaseBackend constructor

docs/changes.rst

@@ -35,6 +35,9 @@ Another great release.
   - :meth:`mopidy.backends.base.BaseLibraryController.search()` now accepts
     keyword arguments of the form ``search(artist=['foo', 'fighters'],
     album=['bar', 'grooves'])``.
+  - :meth:`mopidy.backends.base.BaseBackend()` now accepts an
+    ``output_connection`` which it can use to send messages (i.e. audio data)
+    to the output process.
 
 
 

mopidy/backends/base/__init__.py

@@ -23,13 +23,17 @@ class BaseBackend(object):
     :param core_queue: a queue for sending messages to
         :class:`mopidy.process.CoreProcess`
     :type core_queue: :class:`multiprocessing.Queue`
+    :param output_connection: a connection for sending messages to the
+        output process
+    :type output_connection: :class:`multiprocessing.Connection`
     :param mixer: either a mixer instance, or :class:`None` to use the mixer
         defined in settings
     :type mixer: :class:`mopidy.mixers.BaseMixer` or :class:`None`
     """
 
-    def __init__(self, core_queue=None, mixer=None):
+    def __init__(self, core_queue=None, output_connection=None, mixer=None):
         self.core_queue = core_queue
+        self.output_connection = output_connection
         if mixer is not None:
             self.mixer = mixer
         else: