diff options
| -rw-r--r-- | Doc/library/threading.rst | 18 | ||||
| -rw-r--r-- | Lib/test/lock_tests.py | 13 | ||||
| -rw-r--r-- | Lib/threading.py | 14 | ||||
| -rw-r--r-- | Misc/ACKS | 1 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
5 files changed, 40 insertions, 9 deletions
diff --git a/Doc/library/threading.rst b/Doc/library/threading.rst index 1f2b763..0ce6c63 100644 --- a/Doc/library/threading.rst +++ b/Doc/library/threading.rst @@ -596,7 +596,7 @@ waiting until some other thread calls :meth:`release`. defaults to ``1``. If the *value* given is less than 0, :exc:`ValueError` is raised. - .. method:: acquire(blocking=True) + .. method:: acquire(blocking=True, timeout=None) Acquire a semaphore. @@ -607,14 +607,18 @@ waiting until some other thread calls :meth:`release`. interlocking so that if multiple :meth:`acquire` calls are blocked, :meth:`release` will wake exactly one of them up. The implementation may pick one at random, so the order in which blocked threads are awakened - should not be relied on. There is no return value in this case. - - When invoked with *blocking* set to true, do the same thing as when called - without arguments, and return true. + should not be relied on. Returns true (or blocks indefinitely). When invoked with *blocking* set to false, do not block. If a call - without an argument would block, return false immediately; otherwise, do - the same thing as when called without arguments, and return true. + without an argument would block, return false immediately; otherwise, + do the same thing as when called without arguments, and return true. + + When invoked with a *timeout* other than None, it will block for at + most *timeout* seconds. If acquire does not complete successfully in + that interval, return false. Return true otherwise. + + .. versionchanged:: 3.2 + The *timeout* parameter is new. .. method:: release() 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 @@ class BaseSemaphoreTests(BaseTestCase): # 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 @@ class _Semaphore(_Verbose): 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 @@ class _Semaphore(_Verbose): 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__: @@ -431,6 +431,7 @@ Ivan Krstić Andrew Kuchling Vladimir Kushnir Cameron Laird +Torsten Landschoff Tino Lange Andrew Langmead Detlef Lannert @@ -315,6 +315,9 @@ C-API Library ------- +- Issue #850728: Add a *timeout* parameter to the `acquire()` method of + `threading.Semaphore` objects. Patch by Torsten Landschoff. + - Issue #8322: Add a *ciphers* argument to SSL sockets, so as to change the available cipher list. Helps fix test_ssl with OpenSSL 1.0.0. |