Optimizes checking ready state of sources during sorting.

The main bottle neck here was using `len`.
A boolean check is a sufficient test for more items in the queue.

Also, uses all instead of several functions.

tests/test_sorting.py

@@ -23,9 +23,7 @@ from collections import deque
 from zipline import ndict
 from zipline.gens.sort import (
     date_sort,
-    ready,
     done,
-    queue_is_ready,
     queue_is_done
 )
 from zipline.gens.utils import alternate, done_message
@@ -44,21 +42,17 @@ class HelperTestCase(TestCase):
     def test_individual_queue_logic(self):
         queue = deque()
         # Empty queues are neither done nor ready.
-        assert not queue_is_ready(queue)
         assert not queue_is_done(queue)
 
         queue.append(to_dt('foo'))
-        assert queue_is_ready(queue)
         assert not queue_is_done(queue)
 
         queue.appendleft(to_dt('DONE'))
-        assert queue_is_ready(queue)
 
         # Checking done when we have a message after done will trip an assert.
         self.assertRaises(AssertionError, queue_is_done, queue)
 
         queue.pop()
-        assert queue_is_ready(queue)
         assert queue_is_done(queue)
 
     def test_pop_logic(self):
@@ -67,32 +61,27 @@ class HelperTestCase(TestCase):
         for id in ids:
             sources[id] = deque()
 
-        assert not ready(sources)
         assert not done(sources)
 
         # All sources must have a message to be ready/done
         sources['a'].append(to_dt("datetime"))
-        assert not ready(sources)
         assert not done(sources)
         sources['a'].pop()
 
         for id in ids:
             sources[id].append(to_dt("datetime"))
 
-        assert ready(sources)
         assert not done(sources)
 
         for id in ids:
             sources[id].appendleft(to_dt("DONE"))
 
         # ["DONE", message] will trip an assert in queue_is_done.
-        assert ready(sources)
         self.assertRaises(AssertionError, done, sources)
 
         for id in ids:
             sources[id].pop()
 
-        assert ready(sources)
         assert done(sources)
 
 

zipline/gens/sort.py

@@ -56,7 +56,7 @@ def date_sort(stream_in, source_ids):
         # Only pop messages when we have a pending message from
         # all datasources. Stop if all sources have signalled done.
 
-        while ready(sources) and not done(sources):
+        while all(sources.values()) and not done(sources):
             message = pop_oldest(sources)
             assert_sort_protocol(message)
             yield message
@@ -68,21 +68,6 @@ def date_sort(stream_in, source_ids):
             "Bad last message in date_sort on exit: %s" % queue
 
 
-def ready(sources):
-    """
-    Feed is ready when every internal queue has at least one
-    message. Note that this include DONE messages, so done(sources) is
-    True only if ready(sources).
-    """
-    assert isinstance(sources, dict)
-    return all((queue_is_ready(source) for source in sources.itervalues()))
-
-
-def queue_is_ready(queue):
-    assert isinstance(queue, deque)
-    return len(queue) > 0
-
-
 def done(sources):
     """Feed is done when all internal queues have only a "DONE" message."""
     assert isinstance(sources, dict)