Make the return values of Client.transport_query() more Pythonic

jack.py

@@ -676,6 +676,20 @@ def transport_stop(self):
         """Stop JACK transport."""
         _lib.jack_transport_stop(self._ptr)
 
+    @property
+    def transport_state(self):
+        """JACK transport state.
+
+        This is one of :attr:`STOPPED`, :attr:`ROLLING`,
+        :attr:`STARTING`, :attr:`NETSTARTING`.
+
+        See Also
+        --------
+        transport_query
+
+        """
+        return TransportState(_lib.jack_transport_query(self._ptr, _ffi.NULL))
+
     def transport_locate(self, frame):
         """Reposition the JACK transport to a new frame number.
 
@@ -691,6 +705,46 @@ def transport_locate(self, frame):
     def transport_query(self):
         """Query the current transport state and position.
 
+        This is a convenience function that does the same as
+        :meth:`transport_query_struct` but it only returns the valid
+        fields in an easy-to-use ``dict``.
+
+        Returns
+        -------
+        state : TransportState
+            The transport state can take following values:
+            :attr:`STOPPED`, :attr:`ROLLING`, :attr:`STARTING` and
+            :attr:`NETSTARTING`.
+        position : dict
+            A dictionary containing only the valid fields of the
+            structure returned by :meth:`transport_query_struct`.
+
+        See Also
+        --------
+        :attr:`transport_state`
+
+        """
+        state, pos = self.transport_query_struct()
+        assert pos.unique_1 == pos.unique_2
+
+        keys = ['usecs', 'frame_rate', 'frame']
+        if pos.valid & _lib.JackPositionBBT:
+            keys += ['bar', 'beat', 'tick', 'bar_start_tick', 'beats_per_bar',
+                     'beat_type', 'ticks_per_beat', 'beats_per_minute']
+        if pos.valid & _lib.JackPositionTimecode:
+            keys += ['frame_time', 'next_time']
+        if pos.valid & _lib.JackBBTFrameOffset:
+            keys += ['bbt_offset']
+        if pos.valid & _lib.JackAudioVideoRatio:
+            keys += ['audio_frames_per_video_frame']
+        if pos.valid & _lib.JackVideoFrameOffset:
+            keys += ['video_offset']
+
+        return TransportState(state), dict((k, getattr(pos, k)) for k in keys)
+
+    def transport_query_struct(self):
+        """Query the current transport state and position.
+
         This function is realtime-safe, and can be called from any
         thread.  If called from the process thread, the returned
         position corresponds to the first frame of the current cycle and
@@ -708,6 +762,10 @@ def transport_query(self):
 
             __ http://jackaudio.org/files/docs/html/structjack__position__t.html
 
+        See Also
+        --------
+        transport_query
+
         """
         state = _lib.jack_transport_query(self._ptr, self._position)
         return state, self._position
@@ -2160,9 +2218,13 @@ def redirected(self, *args):
 
     names = set(['__gt__', '__ge__'])
     names.update(numbers.Integral.__abstractmethods__)
-    methods = dict((name, redirect(name)) for name in names)
-    methods.update({'__eq__': lambda self, other: int(self) == other})
-    return type("_StatusBase", (), methods)
+    namespace = dict((name, redirect(name)) for name in names)
+    namespace.update({
+        '__slots__': '_code',
+        '__init__': lambda self, code: setattr(self, '_code', code),
+        '__eq__': lambda self, other: int(self) == other,
+    })
+    return type("_StatusBase", (), namespace)
 
 _StatusBase = _make_statusbase()
 del _make_statusbase
@@ -2172,8 +2234,7 @@ class Status(_StatusBase):
 
     """Representation of the JACK status bits."""
 
-    def __init__(self, statuscode):
-        self._code = statuscode
+    __slots__ = ()
 
     def __repr__(self):
         flags = ", ".join(name for name in dir(self)
@@ -2266,6 +2327,27 @@ def _hasflag(self, flag):
         return bool(self & flag)
 
 
+class TransportState(_StatusBase):
+
+    """Representation of the JACK transport state.
+
+    See Also
+    --------
+    :attr:`Client.transport_state`, :meth:`Client.transport_query`
+
+    """
+
+    __slots__ = ()
+
+    def __repr__(self):
+        return "jack." + {
+            _lib.JackTransportStopped: 'STOPPED',
+            _lib.JackTransportRolling: 'ROLLING',
+            _lib.JackTransportStarting: 'STARTING',
+            _lib.JackTransportNetStarting: 'NETSTARTING',
+        }[int(self)]
+
+
 class JackError(Exception):
 
     """Exception for all kinds of JACK-related errors."""