bpo-32568: make select.epoll() and its docs consistent (#7840)

* `flags` is indeed deprecated, but there is a validation on its value for
  backwards compatibility reasons.  This adds mention of this in the docs.
* The docs say that `sizehint` is deprecated and ignored, but it is still
  used when `epoll_create1()` is unavailable. This adds mention of this in
  the docs.
* `sizehint=-1` is acceptable again, and is replaced with `FD_SETSIZE-1`.
  This is needed to have a default value available at the Python level,
  since `FD_SETSIZE` is not exposed to Python. (see: bpo-31938)
* Reject `sizehint=0` since it is invalid to pass on to `epoll_create()`.

The relevant tests have also been updated.
This commit is contained in:
Tal Einat 2018-06-30 15:43:23 +03:00 committed by GitHub
parent 5bb5bbfca8
commit 0cdf5f4289
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 34 additions and 14 deletions

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@ -57,7 +57,16 @@ The module defines the following:
(Only supported on Linux 2.5.44 and newer.) Return an edge polling object,
which can be used as Edge or Level Triggered interface for I/O
events. *sizehint* and *flags* are deprecated and completely ignored.
events.
*sizehint* informs epoll about the expected number of events to be
registered. It must be positive, or `-1` to use the default. It is only
used on older systems where :c:func:`epoll_create1` is not available;
otherwise it has no effect (though its value is still checked).
*flags* is deprecated and completely ignored. However, when supplied, its
value must be ``0`` or ``select.EPOLL_CLOEXEC``, otherwise ``OSError`` is
raised.
See the :ref:`epoll-objects` section below for the methods supported by
epolling objects.

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@ -74,11 +74,11 @@ class TestEPoll(unittest.TestCase):
ep.close()
self.assertTrue(ep.closed)
self.assertRaises(ValueError, ep.fileno)
if hasattr(select, "EPOLL_CLOEXEC"):
select.epoll(select.EPOLL_CLOEXEC).close()
select.epoll(-1, select.EPOLL_CLOEXEC).close()
select.epoll(flags=select.EPOLL_CLOEXEC).close()
select.epoll(flags=0).close()
self.assertRaises(OSError, select.epoll, flags=12356)
def test_badcreate(self):
self.assertRaises(TypeError, select.epoll, 1, 2, 3)
@ -88,6 +88,13 @@ class TestEPoll(unittest.TestCase):
self.assertRaises(TypeError, select.epoll, ['foo'])
self.assertRaises(TypeError, select.epoll, {})
self.assertRaises(ValueError, select.epoll, 0)
self.assertRaises(ValueError, select.epoll, -2)
self.assertRaises(ValueError, select.epoll, sizehint=-2)
if hasattr(select, "EPOLL_CLOEXEC"):
self.assertRaises(OSError, select.epoll, flags=12356)
def test_context_manager(self):
with select.epoll(16) as ep:
self.assertGreater(ep.fileno(), 0)
@ -117,19 +124,19 @@ class TestEPoll(unittest.TestCase):
try:
# TypeError: argument must be an int, or have a fileno() method.
self.assertRaises(TypeError, ep.register, object(),
select.EPOLLIN | select.EPOLLOUT)
select.EPOLLIN | select.EPOLLOUT)
self.assertRaises(TypeError, ep.register, None,
select.EPOLLIN | select.EPOLLOUT)
select.EPOLLIN | select.EPOLLOUT)
# ValueError: file descriptor cannot be a negative integer (-1)
self.assertRaises(ValueError, ep.register, -1,
select.EPOLLIN | select.EPOLLOUT)
select.EPOLLIN | select.EPOLLOUT)
# OSError: [Errno 9] Bad file descriptor
self.assertRaises(OSError, ep.register, 10000,
select.EPOLLIN | select.EPOLLOUT)
select.EPOLLIN | select.EPOLLOUT)
# registering twice also raises an exception
ep.register(server, select.EPOLLIN | select.EPOLLOUT)
self.assertRaises(OSError, ep.register, server,
select.EPOLLIN | select.EPOLLOUT)
select.EPOLLIN | select.EPOLLOUT)
finally:
ep.close()
@ -160,9 +167,9 @@ class TestEPoll(unittest.TestCase):
ep = select.epoll(16)
ep.register(server.fileno(),
select.EPOLLIN | select.EPOLLOUT | select.EPOLLET)
select.EPOLLIN | select.EPOLLOUT | select.EPOLLET)
ep.register(client.fileno(),
select.EPOLLIN | select.EPOLLOUT | select.EPOLLET)
select.EPOLLIN | select.EPOLLOUT | select.EPOLLET)
now = time.monotonic()
events = ep.poll(1, 4)

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@ -0,0 +1,2 @@
Make select.epoll() and its documentation consistent regarding *sizehint* and
*flags*.

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@ -1297,14 +1297,17 @@ newPyEpoll_Object(PyTypeObject *type, int sizehint, SOCKET fd)
static PyObject *
pyepoll_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
int flags = 0, sizehint = FD_SETSIZE - 1;
int flags = 0, sizehint = -1;
static char *kwlist[] = {"sizehint", "flags", NULL};
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|ii:epoll", kwlist,
&sizehint, &flags))
return NULL;
if (sizehint < 0) {
PyErr_SetString(PyExc_ValueError, "negative sizehint");
if (sizehint == -1) {
sizehint = FD_SETSIZE - 1;
}
else if (sizehint <= 0) {
PyErr_SetString(PyExc_ValueError, "sizehint must be positive or -1");
return NULL;
}
@ -1314,7 +1317,6 @@ pyepoll_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
return NULL;
}
#endif
return newPyEpoll_Object(type, sizehint, -1);
}