Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 1 | """Selectors module. |
| 2 | |
| 3 | This module allows high-level and efficient I/O multiplexing, built upon the |
| 4 | `select` module primitives. |
| 5 | """ |
| 6 | |
| 7 | |
Victor Stinner | da492a8 | 2014-02-20 10:37:27 +0100 | [diff] [blame] | 8 | from abc import ABCMeta, abstractmethod |
Serhiy Storchaka | 2e576f5 | 2017-04-24 09:05:00 +0300 | [diff] [blame] | 9 | from collections import namedtuple |
| 10 | from collections.abc import Mapping |
Victor Stinner | dcd9740 | 2014-01-31 12:12:53 +0100 | [diff] [blame] | 11 | import math |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 12 | import select |
| 13 | import sys |
| 14 | |
| 15 | |
| 16 | # generic events, that must be mapped to implementation-specific ones |
| 17 | EVENT_READ = (1 << 0) |
| 18 | EVENT_WRITE = (1 << 1) |
| 19 | |
| 20 | |
| 21 | def _fileobj_to_fd(fileobj): |
| 22 | """Return a file descriptor from a file object. |
| 23 | |
| 24 | Parameters: |
| 25 | fileobj -- file object or file descriptor |
| 26 | |
| 27 | Returns: |
| 28 | corresponding file descriptor |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 29 | |
| 30 | Raises: |
| 31 | ValueError if the object is invalid |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 32 | """ |
| 33 | if isinstance(fileobj, int): |
| 34 | fd = fileobj |
| 35 | else: |
| 36 | try: |
| 37 | fd = int(fileobj.fileno()) |
| 38 | except (AttributeError, TypeError, ValueError): |
| 39 | raise ValueError("Invalid file object: " |
| 40 | "{!r}".format(fileobj)) from None |
| 41 | if fd < 0: |
| 42 | raise ValueError("Invalid file descriptor: {}".format(fd)) |
| 43 | return fd |
| 44 | |
| 45 | |
| 46 | SelectorKey = namedtuple('SelectorKey', ['fileobj', 'fd', 'events', 'data']) |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 47 | |
Yury Selivanov | 0c6a344 | 2016-03-02 10:37:59 -0500 | [diff] [blame] | 48 | SelectorKey.__doc__ = """SelectorKey(fileobj, fd, events, data) |
| 49 | |
| 50 | Object used to associate a file object to its backing |
| 51 | file descriptor, selected event mask, and attached data. |
| 52 | """ |
| 53 | if sys.version_info >= (3, 5): |
| 54 | SelectorKey.fileobj.__doc__ = 'File object registered.' |
| 55 | SelectorKey.fd.__doc__ = 'Underlying file descriptor.' |
| 56 | SelectorKey.events.__doc__ = 'Events that must be waited for on this file object.' |
| 57 | SelectorKey.data.__doc__ = ('''Optional opaque data associated to this file object. |
| 58 | For example, this could be used to store a per-client session ID.''') |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 59 | |
Abhijeet Kasurde | bcd4783 | 2020-07-23 08:43:37 +0530 | [diff] [blame] | 60 | |
Charles-François Natali | 4574b49 | 2013-10-30 20:31:04 +0100 | [diff] [blame] | 61 | class _SelectorMapping(Mapping): |
| 62 | """Mapping of file objects to selector keys.""" |
| 63 | |
| 64 | def __init__(self, selector): |
| 65 | self._selector = selector |
| 66 | |
| 67 | def __len__(self): |
| 68 | return len(self._selector._fd_to_key) |
| 69 | |
| 70 | def __getitem__(self, fileobj): |
| 71 | try: |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 72 | fd = self._selector._fileobj_lookup(fileobj) |
| 73 | return self._selector._fd_to_key[fd] |
Charles-François Natali | 4574b49 | 2013-10-30 20:31:04 +0100 | [diff] [blame] | 74 | except KeyError: |
| 75 | raise KeyError("{!r} is not registered".format(fileobj)) from None |
| 76 | |
| 77 | def __iter__(self): |
| 78 | return iter(self._selector._fd_to_key) |
| 79 | |
| 80 | |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 81 | class BaseSelector(metaclass=ABCMeta): |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 82 | """Selector abstract base class. |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 83 | |
| 84 | A selector supports registering file objects to be monitored for specific |
| 85 | I/O events. |
| 86 | |
| 87 | A file object is a file descriptor or any object with a `fileno()` method. |
| 88 | An arbitrary object can be attached to the file object, which can be used |
| 89 | for example to store context information, a callback, etc. |
| 90 | |
| 91 | A selector can use various implementations (select(), poll(), epoll()...) |
| 92 | depending on the platform. The default `Selector` class uses the most |
Yury Selivanov | b0b0e62 | 2014-02-18 22:27:48 -0500 | [diff] [blame] | 93 | efficient implementation on the current platform. |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 94 | """ |
| 95 | |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 96 | @abstractmethod |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 97 | def register(self, fileobj, events, data=None): |
| 98 | """Register a file object. |
| 99 | |
| 100 | Parameters: |
| 101 | fileobj -- file object or file descriptor |
| 102 | events -- events to monitor (bitwise mask of EVENT_READ|EVENT_WRITE) |
| 103 | data -- attached data |
| 104 | |
| 105 | Returns: |
| 106 | SelectorKey instance |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 107 | |
| 108 | Raises: |
| 109 | ValueError if events is invalid |
| 110 | KeyError if fileobj is already registered |
| 111 | OSError if fileobj is closed or otherwise is unacceptable to |
| 112 | the underlying system call (if a system call is made) |
| 113 | |
| 114 | Note: |
| 115 | OSError may or may not be raised |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 116 | """ |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 117 | raise NotImplementedError |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 118 | |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 119 | @abstractmethod |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 120 | def unregister(self, fileobj): |
| 121 | """Unregister a file object. |
| 122 | |
| 123 | Parameters: |
| 124 | fileobj -- file object or file descriptor |
| 125 | |
| 126 | Returns: |
| 127 | SelectorKey instance |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 128 | |
| 129 | Raises: |
| 130 | KeyError if fileobj is not registered |
| 131 | |
| 132 | Note: |
| 133 | If fileobj is registered but has since been closed this does |
| 134 | *not* raise OSError (even if the wrapped syscall does) |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 135 | """ |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 136 | raise NotImplementedError |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 137 | |
| 138 | def modify(self, fileobj, events, data=None): |
| 139 | """Change a registered file object monitored events or attached data. |
| 140 | |
| 141 | Parameters: |
| 142 | fileobj -- file object or file descriptor |
| 143 | events -- events to monitor (bitwise mask of EVENT_READ|EVENT_WRITE) |
| 144 | data -- attached data |
| 145 | |
| 146 | Returns: |
| 147 | SelectorKey instance |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 148 | |
| 149 | Raises: |
| 150 | Anything that unregister() or register() raises |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 151 | """ |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 152 | self.unregister(fileobj) |
| 153 | return self.register(fileobj, events, data) |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 154 | |
| 155 | @abstractmethod |
| 156 | def select(self, timeout=None): |
| 157 | """Perform the actual selection, until some monitored file objects are |
| 158 | ready or a timeout expires. |
| 159 | |
| 160 | Parameters: |
| 161 | timeout -- if timeout > 0, this specifies the maximum wait time, in |
| 162 | seconds |
| 163 | if timeout <= 0, the select() call won't block, and will |
| 164 | report the currently ready file objects |
| 165 | if timeout is None, select() will block until a monitored |
| 166 | file object becomes ready |
| 167 | |
| 168 | Returns: |
| 169 | list of (key, events) for ready file objects |
| 170 | `events` is a bitwise mask of EVENT_READ|EVENT_WRITE |
| 171 | """ |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 172 | raise NotImplementedError |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 173 | |
| 174 | def close(self): |
| 175 | """Close the selector. |
| 176 | |
| 177 | This must be called to make sure that any underlying resource is freed. |
| 178 | """ |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 179 | pass |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 180 | |
| 181 | def get_key(self, fileobj): |
| 182 | """Return the key associated to a registered file object. |
| 183 | |
| 184 | Returns: |
| 185 | SelectorKey for this file object |
| 186 | """ |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 187 | mapping = self.get_map() |
Victor Stinner | 458fc6f | 2015-01-13 10:00:55 +0100 | [diff] [blame] | 188 | if mapping is None: |
| 189 | raise RuntimeError('Selector is closed') |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 190 | try: |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 191 | return mapping[fileobj] |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 192 | except KeyError: |
| 193 | raise KeyError("{!r} is not registered".format(fileobj)) from None |
| 194 | |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 195 | @abstractmethod |
Charles-François Natali | 4574b49 | 2013-10-30 20:31:04 +0100 | [diff] [blame] | 196 | def get_map(self): |
| 197 | """Return a mapping of file objects to selector keys.""" |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 198 | raise NotImplementedError |
Charles-François Natali | 4574b49 | 2013-10-30 20:31:04 +0100 | [diff] [blame] | 199 | |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 200 | def __enter__(self): |
| 201 | return self |
| 202 | |
| 203 | def __exit__(self, *args): |
| 204 | self.close() |
| 205 | |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 206 | |
| 207 | class _BaseSelectorImpl(BaseSelector): |
| 208 | """Base selector implementation.""" |
| 209 | |
| 210 | def __init__(self): |
| 211 | # this maps file descriptors to keys |
| 212 | self._fd_to_key = {} |
| 213 | # read-only mapping returned by get_map() |
| 214 | self._map = _SelectorMapping(self) |
| 215 | |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 216 | def _fileobj_lookup(self, fileobj): |
| 217 | """Return a file descriptor from a file object. |
| 218 | |
| 219 | This wraps _fileobj_to_fd() to do an exhaustive search in case |
| 220 | the object is invalid but we still have it in our map. This |
| 221 | is used by unregister() so we can unregister an object that |
| 222 | was previously registered even if it is closed. It is also |
| 223 | used by _SelectorMapping. |
| 224 | """ |
| 225 | try: |
| 226 | return _fileobj_to_fd(fileobj) |
| 227 | except ValueError: |
| 228 | # Do an exhaustive search. |
| 229 | for key in self._fd_to_key.values(): |
| 230 | if key.fileobj is fileobj: |
| 231 | return key.fd |
| 232 | # Raise ValueError after all. |
| 233 | raise |
| 234 | |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 235 | def register(self, fileobj, events, data=None): |
| 236 | if (not events) or (events & ~(EVENT_READ | EVENT_WRITE)): |
| 237 | raise ValueError("Invalid events: {!r}".format(events)) |
| 238 | |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 239 | key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data) |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 240 | |
| 241 | if key.fd in self._fd_to_key: |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 242 | raise KeyError("{!r} (FD {}) is already registered" |
| 243 | .format(fileobj, key.fd)) |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 244 | |
| 245 | self._fd_to_key[key.fd] = key |
| 246 | return key |
| 247 | |
| 248 | def unregister(self, fileobj): |
| 249 | try: |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 250 | key = self._fd_to_key.pop(self._fileobj_lookup(fileobj)) |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 251 | except KeyError: |
| 252 | raise KeyError("{!r} is not registered".format(fileobj)) from None |
| 253 | return key |
| 254 | |
| 255 | def modify(self, fileobj, events, data=None): |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 256 | try: |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 257 | key = self._fd_to_key[self._fileobj_lookup(fileobj)] |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 258 | except KeyError: |
| 259 | raise KeyError("{!r} is not registered".format(fileobj)) from None |
| 260 | if events != key.events: |
| 261 | self.unregister(fileobj) |
| 262 | key = self.register(fileobj, events, data) |
| 263 | elif data != key.data: |
| 264 | # Use a shortcut to update the data. |
| 265 | key = key._replace(data=data) |
| 266 | self._fd_to_key[key.fd] = key |
| 267 | return key |
| 268 | |
| 269 | def close(self): |
| 270 | self._fd_to_key.clear() |
Victor Stinner | 38dc250 | 2015-01-13 09:58:33 +0100 | [diff] [blame] | 271 | self._map = None |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 272 | |
| 273 | def get_map(self): |
| 274 | return self._map |
| 275 | |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 276 | def _key_from_fd(self, fd): |
| 277 | """Return the key associated to a given file descriptor. |
| 278 | |
| 279 | Parameters: |
| 280 | fd -- file descriptor |
| 281 | |
| 282 | Returns: |
| 283 | corresponding key, or None if not found |
| 284 | """ |
| 285 | try: |
| 286 | return self._fd_to_key[fd] |
| 287 | except KeyError: |
| 288 | return None |
| 289 | |
| 290 | |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 291 | class SelectSelector(_BaseSelectorImpl): |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 292 | """Select-based selector.""" |
| 293 | |
| 294 | def __init__(self): |
| 295 | super().__init__() |
| 296 | self._readers = set() |
| 297 | self._writers = set() |
| 298 | |
| 299 | def register(self, fileobj, events, data=None): |
| 300 | key = super().register(fileobj, events, data) |
| 301 | if events & EVENT_READ: |
| 302 | self._readers.add(key.fd) |
| 303 | if events & EVENT_WRITE: |
| 304 | self._writers.add(key.fd) |
| 305 | return key |
| 306 | |
| 307 | def unregister(self, fileobj): |
| 308 | key = super().unregister(fileobj) |
| 309 | self._readers.discard(key.fd) |
| 310 | self._writers.discard(key.fd) |
| 311 | return key |
| 312 | |
| 313 | if sys.platform == 'win32': |
| 314 | def _select(self, r, w, _, timeout=None): |
| 315 | r, w, x = select.select(r, w, w, timeout) |
| 316 | return r, w + x, [] |
| 317 | else: |
| 318 | _select = select.select |
| 319 | |
| 320 | def select(self, timeout=None): |
| 321 | timeout = None if timeout is None else max(timeout, 0) |
| 322 | ready = [] |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 323 | try: |
| 324 | r, w, _ = self._select(self._readers, self._writers, [], timeout) |
| 325 | except InterruptedError: |
| 326 | return ready |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 327 | r = set(r) |
| 328 | w = set(w) |
| 329 | for fd in r | w: |
| 330 | events = 0 |
| 331 | if fd in r: |
| 332 | events |= EVENT_READ |
| 333 | if fd in w: |
| 334 | events |= EVENT_WRITE |
| 335 | |
| 336 | key = self._key_from_fd(fd) |
| 337 | if key: |
| 338 | ready.append((key, events & key.events)) |
| 339 | return ready |
| 340 | |
| 341 | |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 342 | class _PollLikeSelector(_BaseSelectorImpl): |
| 343 | """Base class shared between poll, epoll and devpoll selectors.""" |
| 344 | _selector_cls = None |
Giampaolo Rodola | fbfaa6f | 2017-06-09 22:20:41 +0200 | [diff] [blame] | 345 | _EVENT_READ = None |
| 346 | _EVENT_WRITE = None |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 347 | |
| 348 | def __init__(self): |
| 349 | super().__init__() |
| 350 | self._selector = self._selector_cls() |
| 351 | |
| 352 | def register(self, fileobj, events, data=None): |
| 353 | key = super().register(fileobj, events, data) |
| 354 | poller_events = 0 |
| 355 | if events & EVENT_READ: |
| 356 | poller_events |= self._EVENT_READ |
| 357 | if events & EVENT_WRITE: |
| 358 | poller_events |= self._EVENT_WRITE |
| 359 | try: |
| 360 | self._selector.register(key.fd, poller_events) |
Giampaolo Rodola | ced36a9 | 2017-06-12 14:43:40 +0200 | [diff] [blame] | 361 | except: |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 362 | super().unregister(fileobj) |
| 363 | raise |
| 364 | return key |
| 365 | |
| 366 | def unregister(self, fileobj): |
| 367 | key = super().unregister(fileobj) |
| 368 | try: |
| 369 | self._selector.unregister(key.fd) |
| 370 | except OSError: |
| 371 | # This can happen if the FD was closed since it |
| 372 | # was registered. |
| 373 | pass |
| 374 | return key |
| 375 | |
Giampaolo Rodola | fbfaa6f | 2017-06-09 22:20:41 +0200 | [diff] [blame] | 376 | def modify(self, fileobj, events, data=None): |
| 377 | try: |
| 378 | key = self._fd_to_key[self._fileobj_lookup(fileobj)] |
| 379 | except KeyError: |
| 380 | raise KeyError(f"{fileobj!r} is not registered") from None |
| 381 | |
| 382 | changed = False |
| 383 | if events != key.events: |
| 384 | selector_events = 0 |
| 385 | if events & EVENT_READ: |
| 386 | selector_events |= self._EVENT_READ |
| 387 | if events & EVENT_WRITE: |
| 388 | selector_events |= self._EVENT_WRITE |
| 389 | try: |
| 390 | self._selector.modify(key.fd, selector_events) |
Giampaolo Rodola | 05dc20f | 2017-06-11 01:51:52 +0200 | [diff] [blame] | 391 | except: |
Giampaolo Rodola | fbfaa6f | 2017-06-09 22:20:41 +0200 | [diff] [blame] | 392 | super().unregister(fileobj) |
| 393 | raise |
| 394 | changed = True |
| 395 | if data != key.data: |
| 396 | changed = True |
| 397 | |
| 398 | if changed: |
| 399 | key = key._replace(events=events, data=data) |
| 400 | self._fd_to_key[key.fd] = key |
| 401 | return key |
| 402 | |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 403 | def select(self, timeout=None): |
| 404 | # This is shared between poll() and epoll(). |
| 405 | # epoll() has a different signature and handling of timeout parameter. |
| 406 | if timeout is None: |
| 407 | timeout = None |
| 408 | elif timeout <= 0: |
| 409 | timeout = 0 |
| 410 | else: |
| 411 | # poll() has a resolution of 1 millisecond, round away from |
| 412 | # zero to wait *at least* timeout seconds. |
| 413 | timeout = math.ceil(timeout * 1e3) |
| 414 | ready = [] |
| 415 | try: |
| 416 | fd_event_list = self._selector.poll(timeout) |
| 417 | except InterruptedError: |
| 418 | return ready |
| 419 | for fd, event in fd_event_list: |
| 420 | events = 0 |
| 421 | if event & ~self._EVENT_READ: |
| 422 | events |= EVENT_WRITE |
| 423 | if event & ~self._EVENT_WRITE: |
| 424 | events |= EVENT_READ |
| 425 | |
| 426 | key = self._key_from_fd(fd) |
| 427 | if key: |
| 428 | ready.append((key, events & key.events)) |
| 429 | return ready |
| 430 | |
| 431 | |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 432 | if hasattr(select, 'poll'): |
| 433 | |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 434 | class PollSelector(_PollLikeSelector): |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 435 | """Poll-based selector.""" |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 436 | _selector_cls = select.poll |
| 437 | _EVENT_READ = select.POLLIN |
| 438 | _EVENT_WRITE = select.POLLOUT |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 439 | |
| 440 | |
| 441 | if hasattr(select, 'epoll'): |
| 442 | |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 443 | class EpollSelector(_PollLikeSelector): |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 444 | """Epoll-based selector.""" |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 445 | _selector_cls = select.epoll |
| 446 | _EVENT_READ = select.EPOLLIN |
| 447 | _EVENT_WRITE = select.EPOLLOUT |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 448 | |
| 449 | def fileno(self): |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 450 | return self._selector.fileno() |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 451 | |
| 452 | def select(self, timeout=None): |
Victor Stinner | 567b26e | 2014-01-21 21:00:47 +0100 | [diff] [blame] | 453 | if timeout is None: |
| 454 | timeout = -1 |
| 455 | elif timeout <= 0: |
| 456 | timeout = 0 |
Victor Stinner | dcd9740 | 2014-01-31 12:12:53 +0100 | [diff] [blame] | 457 | else: |
| 458 | # epoll_wait() has a resolution of 1 millisecond, round away |
| 459 | # from zero to wait *at least* timeout seconds. |
| 460 | timeout = math.ceil(timeout * 1e3) * 1e-3 |
Yury Selivanov | d60ef4a | 2014-12-08 12:21:58 -0500 | [diff] [blame] | 461 | |
Yury Selivanov | dfc44e0 | 2014-12-08 12:30:10 -0500 | [diff] [blame] | 462 | # epoll_wait() expects `maxevents` to be greater than zero; |
Yury Selivanov | d60ef4a | 2014-12-08 12:21:58 -0500 | [diff] [blame] | 463 | # we want to make sure that `select()` can be called when no |
| 464 | # FD is registered. |
| 465 | max_ev = max(len(self._fd_to_key), 1) |
| 466 | |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 467 | ready = [] |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 468 | try: |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 469 | fd_event_list = self._selector.poll(timeout, max_ev) |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 470 | except InterruptedError: |
| 471 | return ready |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 472 | for fd, event in fd_event_list: |
| 473 | events = 0 |
| 474 | if event & ~select.EPOLLIN: |
| 475 | events |= EVENT_WRITE |
| 476 | if event & ~select.EPOLLOUT: |
| 477 | events |= EVENT_READ |
| 478 | |
| 479 | key = self._key_from_fd(fd) |
| 480 | if key: |
| 481 | ready.append((key, events & key.events)) |
| 482 | return ready |
| 483 | |
| 484 | def close(self): |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 485 | self._selector.close() |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 486 | super().close() |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 487 | |
| 488 | |
Giampaolo Rodola' | f97e829 | 2014-03-20 21:43:41 +0100 | [diff] [blame] | 489 | if hasattr(select, 'devpoll'): |
| 490 | |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 491 | class DevpollSelector(_PollLikeSelector): |
Giampaolo Rodola' | f97e829 | 2014-03-20 21:43:41 +0100 | [diff] [blame] | 492 | """Solaris /dev/poll selector.""" |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 493 | _selector_cls = select.devpoll |
| 494 | _EVENT_READ = select.POLLIN |
| 495 | _EVENT_WRITE = select.POLLOUT |
Giampaolo Rodola' | f97e829 | 2014-03-20 21:43:41 +0100 | [diff] [blame] | 496 | |
| 497 | def fileno(self): |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 498 | return self._selector.fileno() |
Giampaolo Rodola' | f97e829 | 2014-03-20 21:43:41 +0100 | [diff] [blame] | 499 | |
| 500 | def close(self): |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 501 | self._selector.close() |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 502 | super().close() |
Giampaolo Rodola' | f97e829 | 2014-03-20 21:43:41 +0100 | [diff] [blame] | 503 | |
| 504 | |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 505 | if hasattr(select, 'kqueue'): |
| 506 | |
Charles-François Natali | b3330a0a | 2013-12-01 11:04:17 +0100 | [diff] [blame] | 507 | class KqueueSelector(_BaseSelectorImpl): |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 508 | """Kqueue-based selector.""" |
| 509 | |
| 510 | def __init__(self): |
| 511 | super().__init__() |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 512 | self._selector = select.kqueue() |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 513 | |
| 514 | def fileno(self): |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 515 | return self._selector.fileno() |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 516 | |
| 517 | def register(self, fileobj, events, data=None): |
| 518 | key = super().register(fileobj, events, data) |
Yury Selivanov | 525aedc | 2016-09-15 19:30:42 -0400 | [diff] [blame] | 519 | try: |
| 520 | if events & EVENT_READ: |
| 521 | kev = select.kevent(key.fd, select.KQ_FILTER_READ, |
| 522 | select.KQ_EV_ADD) |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 523 | self._selector.control([kev], 0, 0) |
Yury Selivanov | 525aedc | 2016-09-15 19:30:42 -0400 | [diff] [blame] | 524 | if events & EVENT_WRITE: |
| 525 | kev = select.kevent(key.fd, select.KQ_FILTER_WRITE, |
| 526 | select.KQ_EV_ADD) |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 527 | self._selector.control([kev], 0, 0) |
Giampaolo Rodola | 05dc20f | 2017-06-11 01:51:52 +0200 | [diff] [blame] | 528 | except: |
Yury Selivanov | 525aedc | 2016-09-15 19:30:42 -0400 | [diff] [blame] | 529 | super().unregister(fileobj) |
| 530 | raise |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 531 | return key |
| 532 | |
| 533 | def unregister(self, fileobj): |
| 534 | key = super().unregister(fileobj) |
| 535 | if key.events & EVENT_READ: |
| 536 | kev = select.kevent(key.fd, select.KQ_FILTER_READ, |
| 537 | select.KQ_EV_DELETE) |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 538 | try: |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 539 | self._selector.control([kev], 0, 0) |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 540 | except OSError: |
| 541 | # This can happen if the FD was closed since it |
| 542 | # was registered. |
| 543 | pass |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 544 | if key.events & EVENT_WRITE: |
| 545 | kev = select.kevent(key.fd, select.KQ_FILTER_WRITE, |
| 546 | select.KQ_EV_DELETE) |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 547 | try: |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 548 | self._selector.control([kev], 0, 0) |
Guido van Rossum | 9710ff0 | 2013-12-07 15:57:01 -0800 | [diff] [blame] | 549 | except OSError: |
| 550 | # See comment above. |
| 551 | pass |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 552 | return key |
| 553 | |
| 554 | def select(self, timeout=None): |
| 555 | timeout = None if timeout is None else max(timeout, 0) |
Russell Davis | ba1bcff | 2020-04-15 11:57:06 -0700 | [diff] [blame] | 556 | # If max_ev is 0, kqueue will ignore the timeout. For consistent |
| 557 | # behavior with the other selector classes, we prevent that here |
| 558 | # (using max). See https://bugs.python.org/issue29255 |
| 559 | max_ev = max(len(self._fd_to_key), 1) |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 560 | ready = [] |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 561 | try: |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 562 | kev_list = self._selector.control(None, max_ev, timeout) |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 563 | except InterruptedError: |
| 564 | return ready |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 565 | for kev in kev_list: |
| 566 | fd = kev.ident |
| 567 | flag = kev.filter |
| 568 | events = 0 |
| 569 | if flag == select.KQ_FILTER_READ: |
| 570 | events |= EVENT_READ |
| 571 | if flag == select.KQ_FILTER_WRITE: |
| 572 | events |= EVENT_WRITE |
| 573 | |
| 574 | key = self._key_from_fd(fd) |
| 575 | if key: |
| 576 | ready.append((key, events & key.events)) |
| 577 | return ready |
| 578 | |
| 579 | def close(self): |
Giampaolo Rodola | 62c7d90 | 2017-05-20 11:34:44 +0200 | [diff] [blame] | 580 | self._selector.close() |
Yury Selivanov | 90ecfe6 | 2015-05-11 13:48:16 -0400 | [diff] [blame] | 581 | super().close() |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 582 | |
| 583 | |
Abhijeet Kasurde | bcd4783 | 2020-07-23 08:43:37 +0530 | [diff] [blame] | 584 | def _can_use(method): |
| 585 | """Check if we can use the selector depending upon the |
| 586 | operating system. """ |
| 587 | # Implementation based upon https://github.com/sethmlarson/selectors2/blob/master/selectors2.py |
| 588 | selector = getattr(select, method, None) |
| 589 | if selector is None: |
| 590 | # select module does not implement method |
| 591 | return False |
| 592 | # check if the OS and Kernel actually support the method. Call may fail with |
| 593 | # OSError: [Errno 38] Function not implemented |
| 594 | try: |
| 595 | selector_obj = selector() |
| 596 | if method == 'poll': |
| 597 | # check that poll actually works |
| 598 | selector_obj.poll(0) |
| 599 | else: |
| 600 | # close epoll, kqueue, and devpoll fd |
| 601 | selector_obj.close() |
| 602 | return True |
| 603 | except OSError: |
| 604 | return False |
| 605 | |
| 606 | |
Victor Stinner | 53a6d74 | 2015-01-09 00:13:39 +0100 | [diff] [blame] | 607 | # Choose the best implementation, roughly: |
| 608 | # epoll|kqueue|devpoll > poll > select. |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 609 | # select() also can't accept a FD > FD_SETSIZE (usually around 1024) |
Abhijeet Kasurde | bcd4783 | 2020-07-23 08:43:37 +0530 | [diff] [blame] | 610 | if _can_use('kqueue'): |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 611 | DefaultSelector = KqueueSelector |
Abhijeet Kasurde | bcd4783 | 2020-07-23 08:43:37 +0530 | [diff] [blame] | 612 | elif _can_use('epoll'): |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 613 | DefaultSelector = EpollSelector |
Abhijeet Kasurde | bcd4783 | 2020-07-23 08:43:37 +0530 | [diff] [blame] | 614 | elif _can_use('devpoll'): |
Giampaolo Rodola' | f97e829 | 2014-03-20 21:43:41 +0100 | [diff] [blame] | 615 | DefaultSelector = DevpollSelector |
Abhijeet Kasurde | bcd4783 | 2020-07-23 08:43:37 +0530 | [diff] [blame] | 616 | elif _can_use('poll'): |
Charles-François Natali | 243d8d8 | 2013-09-04 19:02:49 +0200 | [diff] [blame] | 617 | DefaultSelector = PollSelector |
| 618 | else: |
| 619 | DefaultSelector = SelectSelector |