Issue #850728: Add a *timeout* parameter to the `acquire()` method of
`threading.Semaphore` objects. Original patch by Torsten Landschoff.
diff --git a/Lib/test/lock_tests.py b/Lib/test/lock_tests.py
index 74db3e4..a288176 100644
--- a/Lib/test/lock_tests.py
+++ b/Lib/test/lock_tests.py
@@ -521,6 +521,19 @@
# ordered.
self.assertEqual(sorted(results), [False] * 7 + [True] * 3 )
+ def test_acquire_timeout(self):
+ sem = self.semtype(2)
+ self.assertRaises(ValueError, sem.acquire, False, timeout=1.0)
+ self.assertTrue(sem.acquire(timeout=0.005))
+ self.assertTrue(sem.acquire(timeout=0.005))
+ self.assertFalse(sem.acquire(timeout=0.005))
+ sem.release()
+ self.assertTrue(sem.acquire(timeout=0.005))
+ t = time.time()
+ self.assertFalse(sem.acquire(timeout=0.5))
+ dt = time.time() - t
+ self.assertTimeout(dt, 0.5)
+
def test_default_value(self):
# The default initial value is 1.
sem = self.semtype()
diff --git a/Lib/threading.py b/Lib/threading.py
index b4d07fe..2ca224e 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -290,8 +290,11 @@
self._cond = Condition(Lock())
self._value = value
- def acquire(self, blocking=True):
+ def acquire(self, blocking=True, timeout=None):
+ if not blocking and timeout is not None:
+ raise ValueError("can't specify timeout for non-blocking acquire")
rc = False
+ endtime = None
self._cond.acquire()
while self._value == 0:
if not blocking:
@@ -299,7 +302,14 @@
if __debug__:
self._note("%s.acquire(%s): blocked waiting, value=%s",
self, blocking, self._value)
- self._cond.wait()
+ if timeout is not None:
+ if endtime is None:
+ endtime = _time() + timeout
+ else:
+ timeout = endtime - _time()
+ if timeout <= 0:
+ break
+ self._cond.wait(timeout)
else:
self._value = self._value - 1
if __debug__: