Issue 10260
Adding the wait_for() method to threading.Condition
diff --git a/Lib/test/lock_tests.py b/Lib/test/lock_tests.py
index d956bb6..b6d818e 100644
--- a/Lib/test/lock_tests.py
+++ b/Lib/test/lock_tests.py
@@ -446,6 +446,46 @@
# In practice, this implementation has no spurious wakeups.
self.assertFalse(result)
+ def test_waitfor(self):
+ cond = self.condtype()
+ state = 0
+ def f():
+ with cond:
+ result = cond.wait_for(lambda : state==4)
+ self.assertTrue(result)
+ self.assertEqual(state, 4)
+ b = Bunch(f, 1)
+ b.wait_for_started()
+ for i in range(5):
+ time.sleep(0.01)
+ with cond:
+ state += 1
+ cond.notify()
+ b.wait_for_finished()
+
+ def test_waitfor_timeout(self):
+ cond = self.condtype()
+ state = 0
+ success = []
+ def f():
+ with cond:
+ dt = time.time()
+ result = cond.wait_for(lambda : state==4, timeout=0.1)
+ dt = time.time() - dt
+ self.assertFalse(result)
+ self.assertTimeout(dt, 0.1)
+ success.append(None)
+ b = Bunch(f, 1)
+ b.wait_for_started()
+ # Only increment 3 times, so state == 4 is never reached.
+ for i in range(3):
+ time.sleep(0.01)
+ with cond:
+ state += 1
+ cond.notify()
+ b.wait_for_finished()
+ self.assertEqual(len(success), 1)
+
class BaseSemaphoreTests(BaseTestCase):
"""
diff --git a/Lib/threading.py b/Lib/threading.py
index 41956ed..b6c1e5d 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -254,6 +254,32 @@
finally:
self._acquire_restore(saved_state)
+ def wait_for(self, predicate, timeout=None):
+ endtime = None
+ waittime = timeout
+ result = predicate()
+ while not result:
+ if waittime is not None:
+ if endtime is None:
+ endtime = _time() + waittime
+ else:
+ waittime = endtime - _time()
+ if waittime <= 0:
+ if __debug__:
+ self._note("%s.wait_for(%r, %r): Timed out.",
+ self, predicate, timeout)
+ break
+ if __debug__:
+ self._note("%s.wait_for(%r, %r): Waiting with timeout=%s.",
+ self, predicate, timeout, waittime)
+ self.wait(waittime)
+ result = predicate()
+ else:
+ if __debug__:
+ self._note("%s.wait_for(%r, %r): Success.",
+ self, predicate, timeout)
+ return result
+
def notify(self, n=1):
if not self._is_owned():
raise RuntimeError("cannot notify on un-acquired lock")
@@ -482,13 +508,12 @@
# Wait in the barrier until we are relased. Raise an exception
# if the barrier is reset or broken.
def _wait(self, timeout):
- while self._state == 0:
- if self._cond.wait(timeout) is False:
- #timed out. Break the barrier
- self._break()
- raise BrokenBarrierError
- if self._state < 0:
- raise BrokenBarrierError
+ if not self._cond.wait_for(lambda : self._state != 0, timeout):
+ #timed out. Break the barrier
+ self._break()
+ raise BrokenBarrierError
+ if self._state < 0:
+ raise BrokenBarrierError
assert self._state == 1
# If we are the last thread to exit the barrier, signal any threads