fb43b31e7c
I included these libraries here, to avoid problems sharing with other users. I will remove them later.
748 lines
27 KiB
Python
748 lines
27 KiB
Python
""" Back-ported, durable, and portable selectors """
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# MIT License
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#
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# Copyright (c) 2017 Seth Michael Larson
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in all
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# copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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from collections import namedtuple, Mapping
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import errno
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import math
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import platform
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import select
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import socket
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import sys
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import time
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try:
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monotonic = time.monotonic
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except AttributeError:
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monotonic = time.time
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__author__ = 'Seth Michael Larson'
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__email__ = 'sethmichaellarson@protonmail.com'
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__version__ = '2.0.2'
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__license__ = 'MIT'
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__url__ = 'https://www.github.com/SethMichaelLarson/selectors2'
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__all__ = ['EVENT_READ',
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'EVENT_WRITE',
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'SelectorKey',
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'DefaultSelector',
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'BaseSelector']
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EVENT_READ = (1 << 0)
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EVENT_WRITE = (1 << 1)
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_DEFAULT_SELECTOR = None
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_SYSCALL_SENTINEL = object() # Sentinel in case a system call returns None.
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_ERROR_TYPES = (OSError, IOError, socket.error)
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try:
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_INTEGER_TYPES = (int, long)
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except NameError:
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_INTEGER_TYPES = (int,)
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SelectorKey = namedtuple('SelectorKey', ['fileobj', 'fd', 'events', 'data'])
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class _SelectorMapping(Mapping):
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""" Mapping of file objects to selector keys """
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def __init__(self, selector):
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self._selector = selector
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def __len__(self):
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return len(self._selector._fd_to_key)
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def __getitem__(self, fileobj):
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try:
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fd = self._selector._fileobj_lookup(fileobj)
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return self._selector._fd_to_key[fd]
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except KeyError:
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raise KeyError("{0!r} is not registered.".format(fileobj))
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def __iter__(self):
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return iter(self._selector._fd_to_key)
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def _fileobj_to_fd(fileobj):
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""" Return a file descriptor from a file object. If
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given an integer will simply return that integer back. """
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if isinstance(fileobj, _INTEGER_TYPES):
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fd = fileobj
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else:
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for _integer_type in _INTEGER_TYPES:
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try:
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fd = _integer_type(fileobj.fileno())
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break
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except (AttributeError, TypeError, ValueError):
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continue
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else:
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raise ValueError("Invalid file object: {0!r}".format(fileobj))
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if fd < 0:
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raise ValueError("Invalid file descriptor: {0}".format(fd))
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return fd
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class BaseSelector(object):
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""" Abstract Selector class
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A selector supports registering file objects to be monitored
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for specific I/O events.
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A file object is a file descriptor or any object with a
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`fileno()` method. An arbitrary object can be attached to the
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file object which can be used for example to store context info,
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a callback, etc.
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A selector can use various implementations (select(), poll(), epoll(),
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and kqueue()) depending on the platform. The 'DefaultSelector' class uses
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the most efficient implementation for the current platform.
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"""
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def __init__(self):
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# Maps file descriptors to keys.
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self._fd_to_key = {}
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# Read-only mapping returned by get_map()
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self._map = _SelectorMapping(self)
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def _fileobj_lookup(self, fileobj):
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""" Return a file descriptor from a file object.
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This wraps _fileobj_to_fd() to do an exhaustive
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search in case the object is invalid but we still
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have it in our map. Used by unregister() so we can
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unregister an object that was previously registered
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even if it is closed. It is also used by _SelectorMapping
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"""
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try:
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return _fileobj_to_fd(fileobj)
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except ValueError:
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# Search through all our mapped keys.
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for key in self._fd_to_key.values():
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if key.fileobj is fileobj:
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return key.fd
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# Raise ValueError after all.
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raise
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def register(self, fileobj, events, data=None):
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""" Register a file object for a set of events to monitor. """
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if (not events) or (events & ~(EVENT_READ | EVENT_WRITE)):
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raise ValueError("Invalid events: {0!r}".format(events))
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key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data)
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if key.fd in self._fd_to_key:
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raise KeyError("{0!r} (FD {1}) is already registered"
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.format(fileobj, key.fd))
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self._fd_to_key[key.fd] = key
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return key
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def unregister(self, fileobj):
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""" Unregister a file object from being monitored. """
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try:
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key = self._fd_to_key.pop(self._fileobj_lookup(fileobj))
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except KeyError:
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raise KeyError("{0!r} is not registered".format(fileobj))
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# Getting the fileno of a closed socket on Windows errors with EBADF.
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except socket.error as err:
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if err.errno != errno.EBADF:
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raise
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else:
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for key in self._fd_to_key.values():
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if key.fileobj is fileobj:
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self._fd_to_key.pop(key.fd)
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break
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else:
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raise KeyError("{0!r} is not registered".format(fileobj))
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return key
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def modify(self, fileobj, events, data=None):
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""" Change a registered file object monitored events and data. """
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# NOTE: Some subclasses optimize this operation even further.
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try:
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key = self._fd_to_key[self._fileobj_lookup(fileobj)]
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except KeyError:
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raise KeyError("{0!r} is not registered".format(fileobj))
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if events != key.events:
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self.unregister(fileobj)
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key = self.register(fileobj, events, data)
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elif data != key.data:
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# Use a shortcut to update the data.
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key = key._replace(data=data)
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self._fd_to_key[key.fd] = key
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return key
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def select(self, timeout=None):
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""" Perform the actual selection until some monitored file objects
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are ready or the timeout expires. """
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raise NotImplementedError()
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def close(self):
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""" Close the selector. This must be called to ensure that all
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underlying resources are freed. """
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self._fd_to_key.clear()
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self._map = None
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def get_key(self, fileobj):
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""" Return the key associated with a registered file object. """
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mapping = self.get_map()
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if mapping is None:
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raise RuntimeError("Selector is closed")
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try:
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return mapping[fileobj]
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except KeyError:
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raise KeyError("{0!r} is not registered".format(fileobj))
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def get_map(self):
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""" Return a mapping of file objects to selector keys """
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return self._map
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def _key_from_fd(self, fd):
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""" Return the key associated to a given file descriptor
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Return None if it is not found. """
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try:
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return self._fd_to_key[fd]
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except KeyError:
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return None
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def __enter__(self):
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return self
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def __exit__(self, *_):
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self.close()
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# Almost all platforms have select.select()
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if hasattr(select, "select"):
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class SelectSelector(BaseSelector):
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""" Select-based selector. """
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def __init__(self):
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super(SelectSelector, self).__init__()
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self._readers = set()
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self._writers = set()
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def register(self, fileobj, events, data=None):
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key = super(SelectSelector, self).register(fileobj, events, data)
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if events & EVENT_READ:
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self._readers.add(key.fd)
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if events & EVENT_WRITE:
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self._writers.add(key.fd)
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return key
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def unregister(self, fileobj):
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key = super(SelectSelector, self).unregister(fileobj)
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self._readers.discard(key.fd)
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self._writers.discard(key.fd)
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return key
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def select(self, timeout=None):
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# Selecting on empty lists on Windows errors out.
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if not len(self._readers) and not len(self._writers):
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return []
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timeout = None if timeout is None else max(timeout, 0.0)
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ready = []
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r, w, _ = _syscall_wrapper(self._wrap_select, True, self._readers,
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self._writers, timeout=timeout)
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r = set(r)
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w = set(w)
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for fd in r | w:
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events = 0
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if fd in r:
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events |= EVENT_READ
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if fd in w:
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events |= EVENT_WRITE
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key = self._key_from_fd(fd)
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if key:
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ready.append((key, events & key.events))
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return ready
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def _wrap_select(self, r, w, timeout=None):
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""" Wrapper for select.select because timeout is a positional arg """
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return select.select(r, w, [], timeout)
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__all__.append('SelectSelector')
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# Jython has a different implementation of .fileno() for socket objects.
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if platform.python_implementation() == 'Jython':
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class _JythonSelectorMapping(object):
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""" This is an implementation of _SelectorMapping that is built
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for use specifically with Jython, which does not provide a hashable
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value from socket.socket.fileno(). """
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def __init__(self, selector):
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assert isinstance(selector, JythonSelectSelector)
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self._selector = selector
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def __len__(self):
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return len(self._selector._sockets)
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def __getitem__(self, fileobj):
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for sock, key in self._selector._sockets:
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if sock is fileobj:
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return key
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else:
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raise KeyError("{0!r} is not registered.".format(fileobj))
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class JythonSelectSelector(SelectSelector):
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""" This is an implementation of SelectSelector that is for Jython
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which works around that Jython's socket.socket.fileno() does not
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return an integer fd value. All SelectorKey.fd will be equal to -1
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and should not be used. This instead uses object id to compare fileobj
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and will only use select.select as it's the only selector that allows
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directly passing in socket objects rather than registering fds.
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See: http://bugs.jython.org/issue1678
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https://wiki.python.org/jython/NewSocketModule#socket.fileno.28.29_does_not_return_an_integer
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"""
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def __init__(self):
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super(JythonSelectSelector, self).__init__()
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self._sockets = [] # Uses a list of tuples instead of dictionary.
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self._map = _JythonSelectorMapping(self)
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self._readers = []
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self._writers = []
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# Jython has a select.cpython_compatible_select function in older versions.
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self._select_func = getattr(select, 'cpython_compatible_select', select.select)
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def register(self, fileobj, events, data=None):
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for sock, _ in self._sockets:
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if sock is fileobj:
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raise KeyError("{0!r} is already registered"
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.format(fileobj, sock))
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key = SelectorKey(fileobj, -1, events, data)
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self._sockets.append((fileobj, key))
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if events & EVENT_READ:
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self._readers.append(fileobj)
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if events & EVENT_WRITE:
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self._writers.append(fileobj)
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return key
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def unregister(self, fileobj):
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for i, (sock, key) in enumerate(self._sockets):
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if sock is fileobj:
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break
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else:
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raise KeyError("{0!r} is not registered.".format(fileobj))
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if key.events & EVENT_READ:
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self._readers.remove(fileobj)
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if key.events & EVENT_WRITE:
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self._writers.remove(fileobj)
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del self._sockets[i]
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return key
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def _wrap_select(self, r, w, timeout=None):
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""" Wrapper for select.select because timeout is a positional arg """
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return self._select_func(r, w, [], timeout)
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__all__.append('JythonSelectSelector')
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SelectSelector = JythonSelectSelector # Override so the wrong selector isn't used.
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if hasattr(select, "poll"):
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class PollSelector(BaseSelector):
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""" Poll-based selector """
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def __init__(self):
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super(PollSelector, self).__init__()
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self._poll = select.poll()
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def register(self, fileobj, events, data=None):
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key = super(PollSelector, self).register(fileobj, events, data)
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event_mask = 0
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if events & EVENT_READ:
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event_mask |= select.POLLIN
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if events & EVENT_WRITE:
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event_mask |= select.POLLOUT
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self._poll.register(key.fd, event_mask)
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return key
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def unregister(self, fileobj):
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key = super(PollSelector, self).unregister(fileobj)
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self._poll.unregister(key.fd)
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return key
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def _wrap_poll(self, timeout=None):
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""" Wrapper function for select.poll.poll() so that
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_syscall_wrapper can work with only seconds. """
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if timeout is not None:
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if timeout <= 0:
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timeout = 0
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else:
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# select.poll.poll() has a resolution of 1 millisecond,
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# round away from zero to wait *at least* timeout seconds.
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timeout = math.ceil(timeout * 1000)
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result = self._poll.poll(timeout)
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return result
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def select(self, timeout=None):
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ready = []
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fd_events = _syscall_wrapper(self._wrap_poll, True, timeout=timeout)
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for fd, event_mask in fd_events:
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events = 0
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if event_mask & ~select.POLLIN:
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events |= EVENT_WRITE
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if event_mask & ~select.POLLOUT:
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events |= EVENT_READ
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key = self._key_from_fd(fd)
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if key:
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ready.append((key, events & key.events))
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return ready
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__all__.append('PollSelector')
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if hasattr(select, "epoll"):
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class EpollSelector(BaseSelector):
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""" Epoll-based selector """
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def __init__(self):
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super(EpollSelector, self).__init__()
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self._epoll = select.epoll()
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def fileno(self):
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return self._epoll.fileno()
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def register(self, fileobj, events, data=None):
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key = super(EpollSelector, self).register(fileobj, events, data)
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events_mask = 0
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if events & EVENT_READ:
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events_mask |= select.EPOLLIN
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if events & EVENT_WRITE:
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events_mask |= select.EPOLLOUT
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_syscall_wrapper(self._epoll.register, False, key.fd, events_mask)
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return key
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def unregister(self, fileobj):
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key = super(EpollSelector, self).unregister(fileobj)
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try:
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_syscall_wrapper(self._epoll.unregister, False, key.fd)
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except _ERROR_TYPES:
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# This can occur when the fd was closed since registry.
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pass
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return key
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|
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def select(self, timeout=None):
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if timeout is not None:
|
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if timeout <= 0:
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timeout = 0.0
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else:
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# select.epoll.poll() has a resolution of 1 millisecond
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# but luckily takes seconds so we don't need a wrapper
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# like PollSelector. Just for better rounding.
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timeout = math.ceil(timeout * 1000) * 0.001
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timeout = float(timeout)
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else:
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timeout = -1.0 # epoll.poll() must have a float.
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# We always want at least 1 to ensure that select can be called
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# with no file descriptors registered. Otherwise will fail.
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max_events = max(len(self._fd_to_key), 1)
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|
|
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ready = []
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fd_events = _syscall_wrapper(self._epoll.poll, True,
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timeout=timeout,
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maxevents=max_events)
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for fd, event_mask in fd_events:
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events = 0
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if event_mask & ~select.EPOLLIN:
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events |= EVENT_WRITE
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if event_mask & ~select.EPOLLOUT:
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events |= EVENT_READ
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key = self._key_from_fd(fd)
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if key:
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ready.append((key, events & key.events))
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return ready
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|
|
def close(self):
|
|
self._epoll.close()
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super(EpollSelector, self).close()
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__all__.append('EpollSelector')
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|
|
|
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if hasattr(select, "devpoll"):
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class DevpollSelector(BaseSelector):
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"""Solaris /dev/poll selector."""
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def __init__(self):
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super(DevpollSelector, self).__init__()
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self._devpoll = select.devpoll()
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def fileno(self):
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return self._devpoll.fileno()
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def register(self, fileobj, events, data=None):
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key = super(DevpollSelector, self).register(fileobj, events, data)
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poll_events = 0
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if events & EVENT_READ:
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poll_events |= select.POLLIN
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if events & EVENT_WRITE:
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poll_events |= select.POLLOUT
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self._devpoll.register(key.fd, poll_events)
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return key
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|
|
def unregister(self, fileobj):
|
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key = super(DevpollSelector, self).unregister(fileobj)
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self._devpoll.unregister(key.fd)
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return key
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|
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def _wrap_poll(self, timeout=None):
|
|
""" Wrapper function for select.poll.poll() so that
|
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_syscall_wrapper can work with only seconds. """
|
|
if timeout is not None:
|
|
if timeout <= 0:
|
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timeout = 0
|
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else:
|
|
# select.devpoll.poll() has a resolution of 1 millisecond,
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|
# round away from zero to wait *at least* timeout seconds.
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|
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._wrap_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._wrap_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._wrap_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._wrap_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._wrap_control, True,
|
|
None, max_events, timeout=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()
|
|
|
|
def _wrap_control(self, changelist, max_events, timeout):
|
|
return self._kqueue.control(changelist, max_events, timeout)
|
|
|
|
__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
|
|
|
|
if recalc_timeout and 'timeout' not in kwargs:
|
|
raise ValueError(
|
|
'Timeout must be in 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') and e.errno is not None:
|
|
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.ETIMEDOUT, 'Connection timed out')
|
|
if recalc_timeout:
|
|
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 platform.python_implementation() == 'Jython': # Platform-specific: Jython
|
|
_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()
|