issue #170: replace Timer.cancelled with Timer.active

It's more flexable: False can represent 'cancelled' or 'expired',
whereas setting cancelled=True for an expired timer didn't feel right.

mitogen/parent.py

@@ -575,7 +575,9 @@ class Timer(object):
     """
     Represents a future event.
     """
-    cancelled = False
+    #: Set to :data:`False` if :meth:`cancel` has been called, or immediately
+    #: prior to being executed by :meth:`TimerList.expire`.
+    active = True
 
     def __init__(self, when, func):
         self.when = when
@@ -598,7 +600,7 @@ class Timer(object):
         Cancel this event. If it has not yet executed, it will not execute
         during any subsequent :meth:`TimerList.expire` call.
         """
-        self.cancelled = True
+        self.active = False
 
 
 class TimerList(object):
@@ -634,7 +636,7 @@ class TimerList(object):
             Floating point delay, or 0.0, or :data:`None` if no events are
             scheduled.
         """
-        while self._lst and self._lst[0].cancelled:
+        while self._lst and not self._lst[0].active:
             heapq.heappop(self._lst)
         if self._lst:
             return max(0, self._lst[0].when - self._now())
@@ -662,7 +664,8 @@ class TimerList(object):
         now = self._now()
         while self._lst and self._lst[0].when <= now:
             timer = heapq.heappop(self._lst)
-            if not timer.cancelled:
+            if timer.active:
+                timer.active = False
                 timer.func()
 
 

tests/timer_test.py

@@ -98,23 +98,31 @@ class ScheduleTest(TimerListMixin, testlib.TestCase):
 class ExpireTest(TimerListMixin, testlib.TestCase):
     def test_in_past(self):
         timer = self.list.schedule(29, mock.Mock())
+        self.assertTrue(timer.active)
         self.list._now = lambda: 30
         self.list.expire()
         self.assertEquals(1, len(timer.func.mock_calls))
+        self.assertFalse(timer.active)
 
     def test_in_future(self):
         timer = self.list.schedule(29, mock.Mock())
+        self.assertTrue(timer.active)
         self.list._now = lambda: 28
         self.list.expire()
         self.assertEquals(0, len(timer.func.mock_calls))
+        self.assertTrue(timer.active)
 
     def test_same_moment(self):
         timer = self.list.schedule(29, mock.Mock())
         timer2 = self.list.schedule(29, mock.Mock())
+        self.assertTrue(timer.active)
+        self.assertTrue(timer2.active)
         self.list._now = lambda: 29
         self.list.expire()
         self.assertEquals(1, len(timer.func.mock_calls))
         self.assertEquals(1, len(timer2.func.mock_calls))
+        self.assertFalse(timer.active)
+        self.assertFalse(timer2.active)
 
     def test_cancelled(self):
         self.list._now = lambda: 29
@@ -131,7 +139,9 @@ class CancelTest(TimerListMixin, testlib.TestCase):
     def test_single_cancel(self):
         self.list._now = lambda: 29
         timer = self.list.schedule(29, mock.Mock())
+        self.assertTrue(timer.active)
         timer.cancel()
+        self.assertFalse(timer.active)
         self.list.expire()
         self.assertEquals(0, len(timer.func.mock_calls))
 
@@ -139,7 +149,9 @@ class CancelTest(TimerListMixin, testlib.TestCase):
         self.list._now = lambda: 29
         timer = self.list.schedule(29, mock.Mock())
         timer.cancel()
+        self.assertFalse(timer.active)
         timer.cancel()
+        self.assertFalse(timer.active)
         self.list.expire()
         self.assertEquals(0, len(timer.func.mock_calls))