Current File : //lib/python3/dist-packages/twisted/internet/test/test_fdset.py
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Tests for implementations of L{IReactorFDSet}.
"""
import os
import socket
import traceback
from unittest import skipIf
from zope.interface import implementer
from twisted.internet.abstract import FileDescriptor
from twisted.internet.interfaces import IReactorFDSet, IReadDescriptor
# twisted.internet.tcp nicely defines some names with proper values on
# several different platforms.
from twisted.internet.tcp import EINPROGRESS, EWOULDBLOCK
from twisted.internet.test.reactormixins import ReactorBuilder
from twisted.python.runtime import platform
from twisted.trial.unittest import SkipTest
def socketpair():
serverSocket = socket.socket()
serverSocket.bind(("127.0.0.1", 0))
serverSocket.listen(1)
try:
client = socket.socket()
try:
client.setblocking(False)
try:
client.connect(("127.0.0.1", serverSocket.getsockname()[1]))
except OSError as e:
if e.args[0] not in (EINPROGRESS, EWOULDBLOCK):
raise
server, addr = serverSocket.accept()
except BaseException:
client.close()
raise
finally:
serverSocket.close()
return client, server
class ReactorFDSetTestsBuilder(ReactorBuilder):
"""
Builder defining tests relating to L{IReactorFDSet}.
"""
requiredInterfaces = [IReactorFDSet]
def _connectedPair(self):
"""
Return the two sockets which make up a new TCP connection.
"""
client, server = socketpair()
self.addCleanup(client.close)
self.addCleanup(server.close)
return client, server
def _simpleSetup(self):
reactor = self.buildReactor()
client, server = self._connectedPair()
fd = FileDescriptor(reactor)
fd.fileno = client.fileno
return reactor, fd, server
def test_addReader(self):
"""
C{reactor.addReader()} accepts an L{IReadDescriptor} provider and calls
its C{doRead} method when there may be data available on its C{fileno}.
"""
reactor, fd, server = self._simpleSetup()
def removeAndStop():
reactor.removeReader(fd)
reactor.stop()
fd.doRead = removeAndStop
reactor.addReader(fd)
server.sendall(b"x")
# The reactor will only stop if it calls fd.doRead.
self.runReactor(reactor)
# Nothing to assert, just be glad we got this far.
def test_removeReader(self):
"""
L{reactor.removeReader()} accepts an L{IReadDescriptor} provider
previously passed to C{reactor.addReader()} and causes it to no longer
be monitored for input events.
"""
reactor, fd, server = self._simpleSetup()
def fail():
self.fail("doRead should not be called")
fd.doRead = fail
reactor.addReader(fd)
reactor.removeReader(fd)
server.sendall(b"x")
# Give the reactor two timed event passes to notice that there's I/O
# (if it is incorrectly watching for I/O).
reactor.callLater(0, reactor.callLater, 0, reactor.stop)
self.runReactor(reactor)
# Getting here means the right thing happened probably.
def test_addWriter(self):
"""
C{reactor.addWriter()} accepts an L{IWriteDescriptor} provider and
calls its C{doWrite} method when it may be possible to write to its
C{fileno}.
"""
reactor, fd, server = self._simpleSetup()
def removeAndStop():
reactor.removeWriter(fd)
reactor.stop()
fd.doWrite = removeAndStop
reactor.addWriter(fd)
self.runReactor(reactor)
# Getting here is great.
def _getFDTest(self, kind):
"""
Helper for getReaders and getWriters tests.
"""
reactor = self.buildReactor()
get = getattr(reactor, "get" + kind + "s")
add = getattr(reactor, "add" + kind)
remove = getattr(reactor, "remove" + kind)
client, server = self._connectedPair()
self.assertNotIn(client, get())
self.assertNotIn(server, get())
add(client)
self.assertIn(client, get())
self.assertNotIn(server, get())
remove(client)
self.assertNotIn(client, get())
self.assertNotIn(server, get())
def test_getReaders(self):
"""
L{IReactorFDSet.getReaders} reflects the additions and removals made
with L{IReactorFDSet.addReader} and L{IReactorFDSet.removeReader}.
"""
self._getFDTest("Reader")
def test_removeWriter(self):
"""
L{reactor.removeWriter()} accepts an L{IWriteDescriptor} provider
previously passed to C{reactor.addWriter()} and causes it to no longer
be monitored for outputability.
"""
reactor, fd, server = self._simpleSetup()
def fail():
self.fail("doWrite should not be called")
fd.doWrite = fail
reactor.addWriter(fd)
reactor.removeWriter(fd)
# Give the reactor two timed event passes to notice that there's I/O
# (if it is incorrectly watching for I/O).
reactor.callLater(0, reactor.callLater, 0, reactor.stop)
self.runReactor(reactor)
# Getting here means the right thing happened probably.
def test_getWriters(self):
"""
L{IReactorFDSet.getWriters} reflects the additions and removals made
with L{IReactorFDSet.addWriter} and L{IReactorFDSet.removeWriter}.
"""
self._getFDTest("Writer")
def test_removeAll(self):
"""
C{reactor.removeAll()} removes all registered L{IReadDescriptor}
providers and all registered L{IWriteDescriptor} providers and returns
them.
"""
reactor = self.buildReactor()
reactor, fd, server = self._simpleSetup()
fd.doRead = lambda: self.fail("doRead should not be called")
fd.doWrite = lambda: self.fail("doWrite should not be called")
server.sendall(b"x")
reactor.addReader(fd)
reactor.addWriter(fd)
removed = reactor.removeAll()
# Give the reactor two timed event passes to notice that there's I/O
# (if it is incorrectly watching for I/O).
reactor.callLater(0, reactor.callLater, 0, reactor.stop)
self.runReactor(reactor)
# Getting here means the right thing happened probably.
self.assertEqual(removed, [fd])
def test_removedFromReactor(self):
"""
A descriptor's C{fileno} method should not be called after the
descriptor has been removed from the reactor.
"""
reactor = self.buildReactor()
descriptor = RemovingDescriptor(reactor)
reactor.callWhenRunning(descriptor.start)
self.runReactor(reactor)
self.assertEqual(descriptor.calls, [])
def test_negativeOneFileDescriptor(self):
"""
If L{FileDescriptor.fileno} returns C{-1}, the descriptor is removed
from the reactor.
"""
reactor = self.buildReactor()
client, server = self._connectedPair()
class DisappearingDescriptor(FileDescriptor):
_fileno = server.fileno()
_received = b""
def fileno(self):
return self._fileno
def doRead(self):
self._fileno = -1
self._received += server.recv(1)
client.send(b"y")
def connectionLost(self, reason):
reactor.stop()
descriptor = DisappearingDescriptor(reactor)
reactor.addReader(descriptor)
client.send(b"x")
self.runReactor(reactor)
self.assertEqual(descriptor._received, b"x")
@skipIf(platform.isWindows(), "Cannot duplicate socket filenos on Windows")
def test_lostFileDescriptor(self):
"""
The file descriptor underlying a FileDescriptor may be closed and
replaced by another at some point. Bytes which arrive on the new
descriptor must not be delivered to the FileDescriptor which was
originally registered with the original descriptor of the same number.
Practically speaking, this is difficult or impossible to detect. The
implementation relies on C{fileno} raising an exception if the original
descriptor has gone away. If C{fileno} continues to return the original
file descriptor value, the reactor may deliver events from that
descriptor. This is a best effort attempt to ease certain debugging
situations. Applications should not rely on it intentionally.
"""
reactor = self.buildReactor()
name = reactor.__class__.__name__
if name in (
"EPollReactor",
"KQueueReactor",
"CFReactor",
"AsyncioSelectorReactor",
):
# Closing a file descriptor immediately removes it from the epoll
# set without generating a notification. That means epollreactor
# will not call any methods on Victim after the close, so there's
# no chance to notice the socket is no longer valid.
raise SkipTest(f"{name!r} cannot detect lost file descriptors")
client, server = self._connectedPair()
class Victim(FileDescriptor):
"""
This L{FileDescriptor} will have its socket closed out from under it
and another socket will take its place. It will raise a
socket.error from C{fileno} after this happens (because socket
objects remember whether they have been closed), so as long as the
reactor calls the C{fileno} method the problem will be detected.
"""
def fileno(self):
return server.fileno()
def doRead(self):
raise Exception("Victim.doRead should never be called")
def connectionLost(self, reason):
"""
When the problem is detected, the reactor should disconnect this
file descriptor. When that happens, stop the reactor so the
test ends.
"""
reactor.stop()
reactor.addReader(Victim())
# Arrange for the socket to be replaced at some unspecified time.
# Significantly, this will not be while any I/O processing code is on
# the stack. It is something that happens independently and cannot be
# relied upon to happen at a convenient time, such as within a call to
# doRead.
def messItUp():
newC, newS = self._connectedPair()
fileno = server.fileno()
server.close()
os.dup2(newS.fileno(), fileno)
newC.send(b"x")
reactor.callLater(0, messItUp)
self.runReactor(reactor)
# If the implementation feels like logging the exception raised by
# MessedUp.fileno, that's fine.
self.flushLoggedErrors(socket.error)
def test_connectionLostOnShutdown(self):
"""
Any file descriptors added to the reactor have their C{connectionLost}
called when C{reactor.stop} is called.
"""
reactor = self.buildReactor()
class DoNothingDescriptor(FileDescriptor):
def doRead(self):
return None
def doWrite(self):
return None
client, server = self._connectedPair()
fd1 = DoNothingDescriptor(reactor)
fd1.fileno = client.fileno
fd2 = DoNothingDescriptor(reactor)
fd2.fileno = server.fileno
reactor.addReader(fd1)
reactor.addWriter(fd2)
reactor.callWhenRunning(reactor.stop)
self.runReactor(reactor)
self.assertTrue(fd1.disconnected)
self.assertTrue(fd2.disconnected)
@implementer(IReadDescriptor)
class RemovingDescriptor:
"""
A read descriptor which removes itself from the reactor as soon as it
gets a chance to do a read and keeps track of when its own C{fileno}
method is called.
@ivar insideReactor: A flag which is true as long as the reactor has
this descriptor as a reader.
@ivar calls: A list of the bottom of the call stack for any call to
C{fileno} when C{insideReactor} is false.
"""
def __init__(self, reactor):
self.reactor = reactor
self.insideReactor = False
self.calls = []
self.read, self.write = socketpair()
def start(self):
self.insideReactor = True
self.reactor.addReader(self)
self.write.send(b"a")
def logPrefix(self):
return "foo"
def doRead(self):
self.reactor.removeReader(self)
self.insideReactor = False
self.reactor.stop()
self.read.close()
self.write.close()
def fileno(self):
if not self.insideReactor:
self.calls.append(traceback.extract_stack(limit=5)[:-1])
return self.read.fileno()
def connectionLost(self, reason):
# Ideally we'd close the descriptors here... but actually
# connectionLost is never called because we remove ourselves from the
# reactor before it stops.
pass
globals().update(ReactorFDSetTestsBuilder.makeTestCaseClasses())
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