--- a/mercurial/selectors2.py Mon Jan 08 16:07:51 2018 -0800
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,745 +0,0 @@
-""" Back-ported, durable, and portable selectors """
-
-# MIT License
-#
-# Copyright (c) 2017 Seth Michael Larson
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in all
-# copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-# SOFTWARE.
-
-# no-check-code
-
-from __future__ import absolute_import
-
-import collections
-import errno
-import math
-import select
-import socket
-import sys
-import time
-
-from . import pycompat
-
-namedtuple = collections.namedtuple
-Mapping = collections.Mapping
-
-try:
- monotonic = time.monotonic
-except AttributeError:
- monotonic = time.time
-
-__author__ = 'Seth Michael Larson'
-__email__ = 'sethmichaellarson@protonmail.com'
-__version__ = '2.0.0'
-__license__ = 'MIT'
-__url__ = 'https://www.github.com/SethMichaelLarson/selectors2'
-
-__all__ = ['EVENT_READ',
- 'EVENT_WRITE',
- 'SelectorKey',
- 'DefaultSelector',
- 'BaseSelector']
-
-EVENT_READ = (1 << 0)
-EVENT_WRITE = (1 << 1)
-_DEFAULT_SELECTOR = None
-_SYSCALL_SENTINEL = object() # Sentinel in case a system call returns None.
-_ERROR_TYPES = (OSError, IOError, socket.error)
-
-
-SelectorKey = namedtuple('SelectorKey', ['fileobj', 'fd', 'events', 'data'])
-
-
-class _SelectorMapping(Mapping):
- """ Mapping of file objects to selector keys """
-
- def __init__(self, selector):
- self._selector = selector
-
- def __len__(self):
- return len(self._selector._fd_to_key)
-
- def __getitem__(self, fileobj):
- try:
- fd = self._selector._fileobj_lookup(fileobj)
- return self._selector._fd_to_key[fd]
- except KeyError:
- raise KeyError("{0!r} is not registered.".format(fileobj))
-
- def __iter__(self):
- return iter(self._selector._fd_to_key)
-
-
-def _fileobj_to_fd(fileobj):
- """ Return a file descriptor from a file object. If
- given an integer will simply return that integer back. """
- if isinstance(fileobj, int):
- fd = fileobj
- else:
- try:
- fd = int(fileobj.fileno())
- except (AttributeError, TypeError, ValueError):
- raise ValueError("Invalid file object: {0!r}".format(fileobj))
- if fd < 0:
- raise ValueError("Invalid file descriptor: {0}".format(fd))
- return fd
-
-
-class BaseSelector(object):
- """ Abstract Selector class
-
- A selector supports registering file objects to be monitored
- for specific I/O events.
-
- A file object is a file descriptor or any object with a
- `fileno()` method. An arbitrary object can be attached to the
- file object which can be used for example to store context info,
- a callback, etc.
-
- A selector can use various implementations (select(), poll(), epoll(),
- and kqueue()) depending on the platform. The 'DefaultSelector' class uses
- the most efficient implementation for the current platform.
- """
- def __init__(self):
- # Maps file descriptors to keys.
- self._fd_to_key = {}
-
- # Read-only mapping returned by get_map()
- self._map = _SelectorMapping(self)
-
- def _fileobj_lookup(self, fileobj):
- """ Return a file descriptor from a file object.
- This wraps _fileobj_to_fd() to do an exhaustive
- search in case the object is invalid but we still
- have it in our map. Used by unregister() so we can
- unregister an object that was previously registered
- even if it is closed. It is also used by _SelectorMapping
- """
- try:
- return _fileobj_to_fd(fileobj)
- except ValueError:
-
- # Search through all our mapped keys.
- for key in self._fd_to_key.values():
- if key.fileobj is fileobj:
- return key.fd
-
- # Raise ValueError after all.
- raise
-
- def register(self, fileobj, events, data=None):
- """ Register a file object for a set of events to monitor. """
- if (not events) or (events & ~(EVENT_READ | EVENT_WRITE)):
- raise ValueError("Invalid events: {0!r}".format(events))
-
- key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data)
-
- if key.fd in self._fd_to_key:
- raise KeyError("{0!r} (FD {1}) is already registered"
- .format(fileobj, key.fd))
-
- self._fd_to_key[key.fd] = key
- return key
-
- def unregister(self, fileobj):
- """ Unregister a file object from being monitored. """
- try:
- key = self._fd_to_key.pop(self._fileobj_lookup(fileobj))
- except KeyError:
- raise KeyError("{0!r} is not registered".format(fileobj))
-
- # Getting the fileno of a closed socket on Windows errors with EBADF.
- except socket.error as err:
- if err.errno != errno.EBADF:
- raise
- else:
- for key in self._fd_to_key.values():
- if key.fileobj is fileobj:
- self._fd_to_key.pop(key.fd)
- break
- else:
- raise KeyError("{0!r} is not registered".format(fileobj))
- return key
-
- def modify(self, fileobj, events, data=None):
- """ Change a registered file object monitored events and data. """
- # NOTE: Some subclasses optimize this operation even further.
- try:
- key = self._fd_to_key[self._fileobj_lookup(fileobj)]
- except KeyError:
- raise KeyError("{0!r} is not registered".format(fileobj))
-
- if events != key.events:
- self.unregister(fileobj)
- key = self.register(fileobj, events, data)
-
- elif data != key.data:
- # Use a shortcut to update the data.
- key = key._replace(data=data)
- self._fd_to_key[key.fd] = key
-
- return key
-
- def select(self, timeout=None):
- """ Perform the actual selection until some monitored file objects
- are ready or the timeout expires. """
- raise NotImplementedError()
-
- def close(self):
- """ Close the selector. This must be called to ensure that all
- underlying resources are freed. """
- self._fd_to_key.clear()
- self._map = None
-
- def get_key(self, fileobj):
- """ Return the key associated with a registered file object. """
- mapping = self.get_map()
- if mapping is None:
- raise RuntimeError("Selector is closed")
- try:
- return mapping[fileobj]
- except KeyError:
- raise KeyError("{0!r} is not registered".format(fileobj))
-
- def get_map(self):
- """ Return a mapping of file objects to selector keys """
- return self._map
-
- def _key_from_fd(self, fd):
- """ Return the key associated to a given file descriptor
- Return None if it is not found. """
- try:
- return self._fd_to_key[fd]
- except KeyError:
- return None
-
- def __enter__(self):
- return self
-
- def __exit__(self, *_):
- self.close()
-
-
-# Almost all platforms have select.select()
-if hasattr(select, "select"):
- class SelectSelector(BaseSelector):
- """ Select-based selector. """
- def __init__(self):
- super(SelectSelector, self).__init__()
- self._readers = set()
- self._writers = set()
-
- def register(self, fileobj, events, data=None):
- key = super(SelectSelector, self).register(fileobj, events, data)
- if events & EVENT_READ:
- self._readers.add(key.fd)
- if events & EVENT_WRITE:
- self._writers.add(key.fd)
- return key
-
- def unregister(self, fileobj):
- key = super(SelectSelector, self).unregister(fileobj)
- self._readers.discard(key.fd)
- self._writers.discard(key.fd)
- return key
-
- def select(self, timeout=None):
- # Selecting on empty lists on Windows errors out.
- if not len(self._readers) and not len(self._writers):
- return []
-
- timeout = None if timeout is None else max(timeout, 0.0)
- ready = []
- r, w, _ = _syscall_wrapper(self._wrap_select, True, self._readers,
- self._writers, timeout)
- r = set(r)
- w = set(w)
- for fd in r | w:
- events = 0
- if fd in r:
- events |= EVENT_READ
- if fd in w:
- events |= EVENT_WRITE
-
- key = self._key_from_fd(fd)
- if key:
- ready.append((key, events & key.events))
- return ready
-
- def _wrap_select(self, r, w, timeout=None):
- """ Wrapper for select.select because timeout is a positional arg """
- return select.select(r, w, [], timeout)
-
- __all__.append('SelectSelector')
-
- # Jython has a different implementation of .fileno() for socket objects.
- if pycompat.isjython:
- class _JythonSelectorMapping(object):
- """ This is an implementation of _SelectorMapping that is built
- for use specifically with Jython, which does not provide a hashable
- value from socket.socket.fileno(). """
-
- def __init__(self, selector):
- assert isinstance(selector, JythonSelectSelector)
- self._selector = selector
-
- def __len__(self):
- return len(self._selector._sockets)
-
- def __getitem__(self, fileobj):
- for sock, key in self._selector._sockets:
- if sock is fileobj:
- return key
- else:
- raise KeyError("{0!r} is not registered.".format(fileobj))
-
- class JythonSelectSelector(SelectSelector):
- """ This is an implementation of SelectSelector that is for Jython
- which works around that Jython's socket.socket.fileno() does not
- return an integer fd value. All SelectorKey.fd will be equal to -1
- and should not be used. This instead uses object id to compare fileobj
- and will only use select.select as it's the only selector that allows
- directly passing in socket objects rather than registering fds.
- See: http://bugs.jython.org/issue1678
- https://wiki.python.org/jython/NewSocketModule#socket.fileno.28.29_does_not_return_an_integer
- """
-
- def __init__(self):
- super(JythonSelectSelector, self).__init__()
-
- self._sockets = [] # Uses a list of tuples instead of dictionary.
- self._map = _JythonSelectorMapping(self)
- self._readers = []
- self._writers = []
-
- # Jython has a select.cpython_compatible_select function in older versions.
- self._select_func = getattr(select, 'cpython_compatible_select', select.select)
-
- def register(self, fileobj, events, data=None):
- for sock, _ in self._sockets:
- if sock is fileobj:
- raise KeyError("{0!r} is already registered"
- .format(fileobj, sock))
-
- key = SelectorKey(fileobj, -1, events, data)
- self._sockets.append((fileobj, key))
-
- if events & EVENT_READ:
- self._readers.append(fileobj)
- if events & EVENT_WRITE:
- self._writers.append(fileobj)
- return key
-
- def unregister(self, fileobj):
- for i, (sock, key) in enumerate(self._sockets):
- if sock is fileobj:
- break
- else:
- raise KeyError("{0!r} is not registered.".format(fileobj))
-
- if key.events & EVENT_READ:
- self._readers.remove(fileobj)
- if key.events & EVENT_WRITE:
- self._writers.remove(fileobj)
-
- del self._sockets[i]
- return key
-
- def _wrap_select(self, r, w, timeout=None):
- """ Wrapper for select.select because timeout is a positional arg """
- return self._select_func(r, w, [], timeout)
-
- __all__.append('JythonSelectSelector')
- SelectSelector = JythonSelectSelector # Override so the wrong selector isn't used.
-
-
-if hasattr(select, "poll"):
- class PollSelector(BaseSelector):
- """ Poll-based selector """
- def __init__(self):
- super(PollSelector, self).__init__()
- self._poll = select.poll()
-
- def register(self, fileobj, events, data=None):
- key = super(PollSelector, self).register(fileobj, events, data)
- event_mask = 0
- if events & EVENT_READ:
- event_mask |= select.POLLIN
- if events & EVENT_WRITE:
- event_mask |= select.POLLOUT
- self._poll.register(key.fd, event_mask)
- return key
-
- def unregister(self, fileobj):
- key = super(PollSelector, self).unregister(fileobj)
- self._poll.unregister(key.fd)
- return key
-
- def _wrap_poll(self, timeout=None):
- """ Wrapper function for select.poll.poll() so that
- _syscall_wrapper can work with only seconds. """
- if timeout is not None:
- if timeout <= 0:
- timeout = 0
- else:
- # select.poll.poll() has a resolution of 1 millisecond,
- # round away from zero to wait *at least* timeout seconds.
- timeout = math.ceil(timeout * 1000)
-
- result = self._poll.poll(timeout)
- return result
-
- def select(self, timeout=None):
- ready = []
- fd_events = _syscall_wrapper(self._wrap_poll, True, timeout=timeout)
- for fd, event_mask in fd_events:
- events = 0
- if event_mask & ~select.POLLIN:
- events |= EVENT_WRITE
- if event_mask & ~select.POLLOUT:
- events |= EVENT_READ
-
- key = self._key_from_fd(fd)
- if key:
- ready.append((key, events & key.events))
-
- return ready
-
- __all__.append('PollSelector')
-
-if hasattr(select, "epoll"):
- class EpollSelector(BaseSelector):
- """ Epoll-based selector """
- def __init__(self):
- super(EpollSelector, self).__init__()
- self._epoll = select.epoll()
-
- def fileno(self):
- return self._epoll.fileno()
-
- def register(self, fileobj, events, data=None):
- key = super(EpollSelector, self).register(fileobj, events, data)
- events_mask = 0
- if events & EVENT_READ:
- events_mask |= select.EPOLLIN
- if events & EVENT_WRITE:
- events_mask |= select.EPOLLOUT
- _syscall_wrapper(self._epoll.register, False, key.fd, events_mask)
- return key
-
- def unregister(self, fileobj):
- key = super(EpollSelector, self).unregister(fileobj)
- try:
- _syscall_wrapper(self._epoll.unregister, False, key.fd)
- except _ERROR_TYPES:
- # This can occur when the fd was closed since registry.
- pass
- return key
-
- def select(self, timeout=None):
- if timeout is not None:
- if timeout <= 0:
- timeout = 0.0
- else:
- # select.epoll.poll() has a resolution of 1 millisecond
- # but luckily takes seconds so we don't need a wrapper
- # like PollSelector. Just for better rounding.
- timeout = math.ceil(timeout * 1000) * 0.001
- timeout = float(timeout)
- else:
- timeout = -1.0 # epoll.poll() must have a float.
-
- # We always want at least 1 to ensure that select can be called
- # with no file descriptors registered. Otherwise will fail.
- max_events = max(len(self._fd_to_key), 1)
-
- ready = []
- fd_events = _syscall_wrapper(self._epoll.poll, True,
- timeout=timeout,
- maxevents=max_events)
- for fd, event_mask in fd_events:
- events = 0
- if event_mask & ~select.EPOLLIN:
- events |= EVENT_WRITE
- if event_mask & ~select.EPOLLOUT:
- events |= EVENT_READ
-
- key = self._key_from_fd(fd)
- if key:
- ready.append((key, events & key.events))
- return ready
-
- def close(self):
- self._epoll.close()
- super(EpollSelector, self).close()
-
- __all__.append('EpollSelector')
-
-
-if hasattr(select, "devpoll"):
- class DevpollSelector(BaseSelector):
- """Solaris /dev/poll selector."""
-
- def __init__(self):
- super(DevpollSelector, self).__init__()
- self._devpoll = select.devpoll()
-
- def fileno(self):
- return self._devpoll.fileno()
-
- def register(self, fileobj, events, data=None):
- key = super(DevpollSelector, self).register(fileobj, events, data)
- poll_events = 0
- if events & EVENT_READ:
- poll_events |= select.POLLIN
- if events & EVENT_WRITE:
- poll_events |= select.POLLOUT
- self._devpoll.register(key.fd, poll_events)
- return key
-
- def unregister(self, fileobj):
- key = super(DevpollSelector, self).unregister(fileobj)
- self._devpoll.unregister(key.fd)
- return key
-
- def _wrap_poll(self, timeout=None):
- """ Wrapper function for select.poll.poll() so that
- _syscall_wrapper can work with only seconds. """
- if timeout is not None:
- if timeout <= 0:
- timeout = 0
- else:
- # select.devpoll.poll() has a resolution of 1 millisecond,
- # round away from zero to wait *at least* timeout seconds.
- timeout = math.ceil(timeout * 1000)
-
- result = self._devpoll.poll(timeout)
- return result
-
- def select(self, timeout=None):
- ready = []
- fd_events = _syscall_wrapper(self._wrap_poll, True, timeout=timeout)
- for fd, event_mask in fd_events:
- events = 0
- if event_mask & ~select.POLLIN:
- events |= EVENT_WRITE
- if event_mask & ~select.POLLOUT:
- events |= EVENT_READ
-
- key = self._key_from_fd(fd)
- if key:
- ready.append((key, events & key.events))
-
- return ready
-
- def close(self):
- self._devpoll.close()
- super(DevpollSelector, self).close()
-
- __all__.append('DevpollSelector')
-
-
-if hasattr(select, "kqueue"):
- class KqueueSelector(BaseSelector):
- """ Kqueue / Kevent-based selector """
- def __init__(self):
- super(KqueueSelector, self).__init__()
- self._kqueue = select.kqueue()
-
- def fileno(self):
- return self._kqueue.fileno()
-
- def register(self, fileobj, events, data=None):
- key = super(KqueueSelector, self).register(fileobj, events, data)
- if events & EVENT_READ:
- kevent = select.kevent(key.fd,
- select.KQ_FILTER_READ,
- select.KQ_EV_ADD)
-
- _syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
-
- if events & EVENT_WRITE:
- kevent = select.kevent(key.fd,
- select.KQ_FILTER_WRITE,
- select.KQ_EV_ADD)
-
- _syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
-
- return key
-
- def unregister(self, fileobj):
- key = super(KqueueSelector, self).unregister(fileobj)
- if key.events & EVENT_READ:
- kevent = select.kevent(key.fd,
- select.KQ_FILTER_READ,
- select.KQ_EV_DELETE)
- try:
- _syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
- except _ERROR_TYPES:
- pass
- if key.events & EVENT_WRITE:
- kevent = select.kevent(key.fd,
- select.KQ_FILTER_WRITE,
- select.KQ_EV_DELETE)
- try:
- _syscall_wrapper(self._kqueue.control, False, [kevent], 0, 0)
- except _ERROR_TYPES:
- pass
-
- return key
-
- def select(self, timeout=None):
- if timeout is not None:
- timeout = max(timeout, 0)
-
- max_events = len(self._fd_to_key) * 2
- ready_fds = {}
-
- kevent_list = _syscall_wrapper(self._kqueue.control, True,
- None, max_events, timeout)
-
- for kevent in kevent_list:
- fd = kevent.ident
- event_mask = kevent.filter
- events = 0
- if event_mask == select.KQ_FILTER_READ:
- events |= EVENT_READ
- if event_mask == select.KQ_FILTER_WRITE:
- events |= EVENT_WRITE
-
- key = self._key_from_fd(fd)
- if key:
- if key.fd not in ready_fds:
- ready_fds[key.fd] = (key, events & key.events)
- else:
- old_events = ready_fds[key.fd][1]
- ready_fds[key.fd] = (key, (events | old_events) & key.events)
-
- return list(ready_fds.values())
-
- def close(self):
- self._kqueue.close()
- super(KqueueSelector, self).close()
-
- __all__.append('KqueueSelector')
-
-
-def _can_allocate(struct):
- """ Checks that select structs can be allocated by the underlying
- operating system, not just advertised by the select module. We don't
- check select() because we'll be hopeful that most platforms that
- don't have it available will not advertise it. (ie: GAE) """
- try:
- # select.poll() objects won't fail until used.
- if struct == 'poll':
- p = select.poll()
- p.poll(0)
-
- # All others will fail on allocation.
- else:
- getattr(select, struct)().close()
- return True
- except (OSError, AttributeError):
- return False
-
-
-# Python 3.5 uses a more direct route to wrap system calls to increase speed.
-if sys.version_info >= (3, 5):
- def _syscall_wrapper(func, _, *args, **kwargs):
- """ This is the short-circuit version of the below logic
- because in Python 3.5+ all selectors restart system calls. """
- return func(*args, **kwargs)
-else:
- def _syscall_wrapper(func, recalc_timeout, *args, **kwargs):
- """ Wrapper function for syscalls that could fail due to EINTR.
- All functions should be retried if there is time left in the timeout
- in accordance with PEP 475. """
- timeout = kwargs.get("timeout", None)
- if timeout is None:
- expires = None
- recalc_timeout = False
- else:
- timeout = float(timeout)
- if timeout < 0.0: # Timeout less than 0 treated as no timeout.
- expires = None
- else:
- expires = monotonic() + timeout
-
- args = list(args)
- if recalc_timeout and "timeout" not in kwargs:
- raise ValueError(
- "Timeout must be in args or kwargs to be recalculated")
-
- result = _SYSCALL_SENTINEL
- while result is _SYSCALL_SENTINEL:
- try:
- result = func(*args, **kwargs)
- # OSError is thrown by select.select
- # IOError is thrown by select.epoll.poll
- # select.error is thrown by select.poll.poll
- # Aren't we thankful for Python 3.x rework for exceptions?
- except (OSError, IOError, select.error) as e:
- # select.error wasn't a subclass of OSError in the past.
- errcode = None
- if hasattr(e, "errno"):
- errcode = e.errno
- elif hasattr(e, "args"):
- errcode = e.args[0]
-
- # Also test for the Windows equivalent of EINTR.
- is_interrupt = (errcode == errno.EINTR or (hasattr(errno, "WSAEINTR") and
- errcode == errno.WSAEINTR))
-
- if is_interrupt:
- if expires is not None:
- current_time = monotonic()
- if current_time > expires:
- raise OSError(errno=errno.ETIMEDOUT)
- if recalc_timeout:
- if "timeout" in kwargs:
- kwargs["timeout"] = expires - current_time
- continue
- raise
- return result
-
-
-# Choose the best implementation, roughly:
-# kqueue == devpoll == epoll > poll > select
-# select() also can't accept a FD > FD_SETSIZE (usually around 1024)
-def DefaultSelector():
- """ This function serves as a first call for DefaultSelector to
- detect if the select module is being monkey-patched incorrectly
- by eventlet, greenlet, and preserve proper behavior. """
- global _DEFAULT_SELECTOR
- if _DEFAULT_SELECTOR is None:
- if pycompat.isjython:
- _DEFAULT_SELECTOR = JythonSelectSelector
- elif _can_allocate('kqueue'):
- _DEFAULT_SELECTOR = KqueueSelector
- elif _can_allocate('devpoll'):
- _DEFAULT_SELECTOR = DevpollSelector
- elif _can_allocate('epoll'):
- _DEFAULT_SELECTOR = EpollSelector
- elif _can_allocate('poll'):
- _DEFAULT_SELECTOR = PollSelector
- elif hasattr(select, 'select'):
- _DEFAULT_SELECTOR = SelectSelector
- else: # Platform-specific: AppEngine
- raise RuntimeError('Platform does not have a selector.')
- return _DEFAULT_SELECTOR()