Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 1 | """Base implementation of event loop. |
| 2 | |
| 3 | The event loop can be broken up into a multiplexer (the part |
| 4 | responsible for notifying us of IO events) and the event loop proper, |
| 5 | which wraps a multiplexer with functionality for scheduling callbacks, |
| 6 | immediately or at a given time in the future. |
| 7 | |
| 8 | Whenever a public API takes a callback, subsequent positional |
| 9 | arguments will be passed to the callback if/when it is called. This |
| 10 | avoids the proliferation of trivial lambdas implementing closures. |
| 11 | Keyword arguments for the callback are not supported; this is a |
| 12 | conscious design decision, leaving the door open for keyword arguments |
| 13 | to modify the meaning of the API call itself. |
| 14 | """ |
| 15 | |
| 16 | |
| 17 | import collections |
| 18 | import concurrent.futures |
| 19 | import heapq |
| 20 | import logging |
| 21 | import socket |
| 22 | import subprocess |
| 23 | import time |
| 24 | import os |
| 25 | import sys |
| 26 | |
| 27 | from . import events |
| 28 | from . import futures |
| 29 | from . import tasks |
Guido van Rossum | fc29e0f | 2013-10-17 15:39:45 -0700 | [diff] [blame] | 30 | from .log import logger |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 31 | |
| 32 | |
| 33 | __all__ = ['BaseEventLoop', 'Server'] |
| 34 | |
| 35 | |
| 36 | # Argument for default thread pool executor creation. |
| 37 | _MAX_WORKERS = 5 |
| 38 | |
| 39 | |
| 40 | class _StopError(BaseException): |
| 41 | """Raised to stop the event loop.""" |
| 42 | |
| 43 | |
| 44 | def _raise_stop_error(*args): |
| 45 | raise _StopError |
| 46 | |
| 47 | |
| 48 | class Server(events.AbstractServer): |
| 49 | |
| 50 | def __init__(self, loop, sockets): |
| 51 | self.loop = loop |
| 52 | self.sockets = sockets |
| 53 | self.active_count = 0 |
| 54 | self.waiters = [] |
| 55 | |
| 56 | def attach(self, transport): |
| 57 | assert self.sockets is not None |
| 58 | self.active_count += 1 |
| 59 | |
| 60 | def detach(self, transport): |
| 61 | assert self.active_count > 0 |
| 62 | self.active_count -= 1 |
| 63 | if self.active_count == 0 and self.sockets is None: |
| 64 | self._wakeup() |
| 65 | |
| 66 | def close(self): |
| 67 | sockets = self.sockets |
| 68 | if sockets is not None: |
| 69 | self.sockets = None |
| 70 | for sock in sockets: |
| 71 | self.loop._stop_serving(sock) |
| 72 | if self.active_count == 0: |
| 73 | self._wakeup() |
| 74 | |
| 75 | def _wakeup(self): |
| 76 | waiters = self.waiters |
| 77 | self.waiters = None |
| 78 | for waiter in waiters: |
| 79 | if not waiter.done(): |
| 80 | waiter.set_result(waiter) |
| 81 | |
| 82 | @tasks.coroutine |
| 83 | def wait_closed(self): |
| 84 | if self.sockets is None or self.waiters is None: |
| 85 | return |
| 86 | waiter = futures.Future(loop=self.loop) |
| 87 | self.waiters.append(waiter) |
| 88 | yield from waiter |
| 89 | |
| 90 | |
| 91 | class BaseEventLoop(events.AbstractEventLoop): |
| 92 | |
| 93 | def __init__(self): |
| 94 | self._ready = collections.deque() |
| 95 | self._scheduled = [] |
| 96 | self._default_executor = None |
| 97 | self._internal_fds = 0 |
| 98 | self._running = False |
| 99 | |
| 100 | def _make_socket_transport(self, sock, protocol, waiter=None, *, |
| 101 | extra=None, server=None): |
| 102 | """Create socket transport.""" |
| 103 | raise NotImplementedError |
| 104 | |
| 105 | def _make_ssl_transport(self, rawsock, protocol, sslcontext, waiter, *, |
| 106 | server_side=False, server_hostname=None, |
| 107 | extra=None, server=None): |
| 108 | """Create SSL transport.""" |
| 109 | raise NotImplementedError |
| 110 | |
| 111 | def _make_datagram_transport(self, sock, protocol, |
| 112 | address=None, extra=None): |
| 113 | """Create datagram transport.""" |
| 114 | raise NotImplementedError |
| 115 | |
| 116 | def _make_read_pipe_transport(self, pipe, protocol, waiter=None, |
| 117 | extra=None): |
| 118 | """Create read pipe transport.""" |
| 119 | raise NotImplementedError |
| 120 | |
| 121 | def _make_write_pipe_transport(self, pipe, protocol, waiter=None, |
| 122 | extra=None): |
| 123 | """Create write pipe transport.""" |
| 124 | raise NotImplementedError |
| 125 | |
| 126 | @tasks.coroutine |
| 127 | def _make_subprocess_transport(self, protocol, args, shell, |
| 128 | stdin, stdout, stderr, bufsize, |
| 129 | extra=None, **kwargs): |
| 130 | """Create subprocess transport.""" |
| 131 | raise NotImplementedError |
| 132 | |
| 133 | def _read_from_self(self): |
| 134 | """XXX""" |
| 135 | raise NotImplementedError |
| 136 | |
| 137 | def _write_to_self(self): |
| 138 | """XXX""" |
| 139 | raise NotImplementedError |
| 140 | |
| 141 | def _process_events(self, event_list): |
| 142 | """Process selector events.""" |
| 143 | raise NotImplementedError |
| 144 | |
| 145 | def run_forever(self): |
| 146 | """Run until stop() is called.""" |
| 147 | if self._running: |
| 148 | raise RuntimeError('Event loop is running.') |
| 149 | self._running = True |
| 150 | try: |
| 151 | while True: |
| 152 | try: |
| 153 | self._run_once() |
| 154 | except _StopError: |
| 155 | break |
| 156 | finally: |
| 157 | self._running = False |
| 158 | |
| 159 | def run_until_complete(self, future): |
| 160 | """Run until the Future is done. |
| 161 | |
| 162 | If the argument is a coroutine, it is wrapped in a Task. |
| 163 | |
| 164 | XXX TBD: It would be disastrous to call run_until_complete() |
| 165 | with the same coroutine twice -- it would wrap it in two |
| 166 | different Tasks and that can't be good. |
| 167 | |
| 168 | Return the Future's result, or raise its exception. |
| 169 | """ |
| 170 | future = tasks.async(future, loop=self) |
| 171 | future.add_done_callback(_raise_stop_error) |
| 172 | self.run_forever() |
| 173 | future.remove_done_callback(_raise_stop_error) |
| 174 | if not future.done(): |
| 175 | raise RuntimeError('Event loop stopped before Future completed.') |
| 176 | |
| 177 | return future.result() |
| 178 | |
| 179 | def stop(self): |
| 180 | """Stop running the event loop. |
| 181 | |
| 182 | Every callback scheduled before stop() is called will run. |
| 183 | Callback scheduled after stop() is called won't. However, |
| 184 | those callbacks will run if run() is called again later. |
| 185 | """ |
| 186 | self.call_soon(_raise_stop_error) |
| 187 | |
Antoine Pitrou | 4ca7355 | 2013-10-20 00:54:10 +0200 | [diff] [blame] | 188 | def close(self): |
| 189 | self._ready.clear() |
| 190 | self._scheduled.clear() |
| 191 | executor = self._default_executor |
| 192 | if executor is not None: |
| 193 | self._default_executor = None |
| 194 | executor.shutdown(wait=False) |
| 195 | |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 196 | def is_running(self): |
| 197 | """Returns running status of event loop.""" |
| 198 | return self._running |
| 199 | |
| 200 | def time(self): |
| 201 | """Return the time according to the event loop's clock.""" |
| 202 | return time.monotonic() |
| 203 | |
| 204 | def call_later(self, delay, callback, *args): |
| 205 | """Arrange for a callback to be called at a given time. |
| 206 | |
| 207 | Return a Handle: an opaque object with a cancel() method that |
| 208 | can be used to cancel the call. |
| 209 | |
| 210 | The delay can be an int or float, expressed in seconds. It is |
| 211 | always a relative time. |
| 212 | |
| 213 | Each callback will be called exactly once. If two callbacks |
| 214 | are scheduled for exactly the same time, it undefined which |
| 215 | will be called first. |
| 216 | |
| 217 | Any positional arguments after the callback will be passed to |
| 218 | the callback when it is called. |
| 219 | """ |
| 220 | return self.call_at(self.time() + delay, callback, *args) |
| 221 | |
| 222 | def call_at(self, when, callback, *args): |
| 223 | """Like call_later(), but uses an absolute time.""" |
| 224 | timer = events.TimerHandle(when, callback, args) |
| 225 | heapq.heappush(self._scheduled, timer) |
| 226 | return timer |
| 227 | |
| 228 | def call_soon(self, callback, *args): |
| 229 | """Arrange for a callback to be called as soon as possible. |
| 230 | |
| 231 | This operates as a FIFO queue, callbacks are called in the |
| 232 | order in which they are registered. Each callback will be |
| 233 | called exactly once. |
| 234 | |
| 235 | Any positional arguments after the callback will be passed to |
| 236 | the callback when it is called. |
| 237 | """ |
| 238 | handle = events.make_handle(callback, args) |
| 239 | self._ready.append(handle) |
| 240 | return handle |
| 241 | |
| 242 | def call_soon_threadsafe(self, callback, *args): |
| 243 | """XXX""" |
| 244 | handle = self.call_soon(callback, *args) |
| 245 | self._write_to_self() |
| 246 | return handle |
| 247 | |
| 248 | def run_in_executor(self, executor, callback, *args): |
| 249 | if isinstance(callback, events.Handle): |
| 250 | assert not args |
| 251 | assert not isinstance(callback, events.TimerHandle) |
| 252 | if callback._cancelled: |
| 253 | f = futures.Future(loop=self) |
| 254 | f.set_result(None) |
| 255 | return f |
| 256 | callback, args = callback._callback, callback._args |
| 257 | if executor is None: |
| 258 | executor = self._default_executor |
| 259 | if executor is None: |
| 260 | executor = concurrent.futures.ThreadPoolExecutor(_MAX_WORKERS) |
| 261 | self._default_executor = executor |
| 262 | return futures.wrap_future(executor.submit(callback, *args), loop=self) |
| 263 | |
| 264 | def set_default_executor(self, executor): |
| 265 | self._default_executor = executor |
| 266 | |
| 267 | def getaddrinfo(self, host, port, *, |
| 268 | family=0, type=0, proto=0, flags=0): |
| 269 | return self.run_in_executor(None, socket.getaddrinfo, |
| 270 | host, port, family, type, proto, flags) |
| 271 | |
| 272 | def getnameinfo(self, sockaddr, flags=0): |
| 273 | return self.run_in_executor(None, socket.getnameinfo, sockaddr, flags) |
| 274 | |
| 275 | @tasks.coroutine |
| 276 | def create_connection(self, protocol_factory, host=None, port=None, *, |
| 277 | ssl=None, family=0, proto=0, flags=0, sock=None, |
Guido van Rossum | 21c85a7 | 2013-11-01 14:16:54 -0700 | [diff] [blame^] | 278 | local_addr=None, server_hostname=None): |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 279 | """XXX""" |
Guido van Rossum | 21c85a7 | 2013-11-01 14:16:54 -0700 | [diff] [blame^] | 280 | if server_hostname is not None and not ssl: |
| 281 | raise ValueError('server_hostname is only meaningful with ssl') |
| 282 | |
| 283 | if server_hostname is None and ssl: |
| 284 | # Use host as default for server_hostname. It is an error |
| 285 | # if host is empty or not set, e.g. when an |
| 286 | # already-connected socket was passed or when only a port |
| 287 | # is given. To avoid this error, you can pass |
| 288 | # server_hostname='' -- this will bypass the hostname |
| 289 | # check. (This also means that if host is a numeric |
| 290 | # IP/IPv6 address, we will attempt to verify that exact |
| 291 | # address; this will probably fail, but it is possible to |
| 292 | # create a certificate for a specific IP address, so we |
| 293 | # don't judge it here.) |
| 294 | if not host: |
| 295 | raise ValueError('You must set server_hostname ' |
| 296 | 'when using ssl without a host') |
| 297 | server_hostname = host |
| 298 | |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 299 | if host is not None or port is not None: |
| 300 | if sock is not None: |
| 301 | raise ValueError( |
| 302 | 'host/port and sock can not be specified at the same time') |
| 303 | |
| 304 | f1 = self.getaddrinfo( |
| 305 | host, port, family=family, |
| 306 | type=socket.SOCK_STREAM, proto=proto, flags=flags) |
| 307 | fs = [f1] |
| 308 | if local_addr is not None: |
| 309 | f2 = self.getaddrinfo( |
| 310 | *local_addr, family=family, |
| 311 | type=socket.SOCK_STREAM, proto=proto, flags=flags) |
| 312 | fs.append(f2) |
| 313 | else: |
| 314 | f2 = None |
| 315 | |
| 316 | yield from tasks.wait(fs, loop=self) |
| 317 | |
| 318 | infos = f1.result() |
| 319 | if not infos: |
| 320 | raise OSError('getaddrinfo() returned empty list') |
| 321 | if f2 is not None: |
| 322 | laddr_infos = f2.result() |
| 323 | if not laddr_infos: |
| 324 | raise OSError('getaddrinfo() returned empty list') |
| 325 | |
| 326 | exceptions = [] |
| 327 | for family, type, proto, cname, address in infos: |
| 328 | try: |
| 329 | sock = socket.socket(family=family, type=type, proto=proto) |
| 330 | sock.setblocking(False) |
| 331 | if f2 is not None: |
| 332 | for _, _, _, _, laddr in laddr_infos: |
| 333 | try: |
| 334 | sock.bind(laddr) |
| 335 | break |
| 336 | except OSError as exc: |
| 337 | exc = OSError( |
| 338 | exc.errno, 'error while ' |
| 339 | 'attempting to bind on address ' |
| 340 | '{!r}: {}'.format( |
| 341 | laddr, exc.strerror.lower())) |
| 342 | exceptions.append(exc) |
| 343 | else: |
| 344 | sock.close() |
| 345 | sock = None |
| 346 | continue |
| 347 | yield from self.sock_connect(sock, address) |
| 348 | except OSError as exc: |
| 349 | if sock is not None: |
| 350 | sock.close() |
| 351 | exceptions.append(exc) |
| 352 | else: |
| 353 | break |
| 354 | else: |
| 355 | if len(exceptions) == 1: |
| 356 | raise exceptions[0] |
| 357 | else: |
| 358 | # If they all have the same str(), raise one. |
| 359 | model = str(exceptions[0]) |
| 360 | if all(str(exc) == model for exc in exceptions): |
| 361 | raise exceptions[0] |
| 362 | # Raise a combined exception so the user can see all |
| 363 | # the various error messages. |
| 364 | raise OSError('Multiple exceptions: {}'.format( |
| 365 | ', '.join(str(exc) for exc in exceptions))) |
| 366 | |
| 367 | elif sock is None: |
| 368 | raise ValueError( |
| 369 | 'host and port was not specified and no sock specified') |
| 370 | |
| 371 | sock.setblocking(False) |
| 372 | |
| 373 | protocol = protocol_factory() |
| 374 | waiter = futures.Future(loop=self) |
| 375 | if ssl: |
| 376 | sslcontext = None if isinstance(ssl, bool) else ssl |
| 377 | transport = self._make_ssl_transport( |
| 378 | sock, protocol, sslcontext, waiter, |
Guido van Rossum | 21c85a7 | 2013-11-01 14:16:54 -0700 | [diff] [blame^] | 379 | server_side=False, server_hostname=server_hostname) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 380 | else: |
| 381 | transport = self._make_socket_transport(sock, protocol, waiter) |
| 382 | |
| 383 | yield from waiter |
| 384 | return transport, protocol |
| 385 | |
| 386 | @tasks.coroutine |
| 387 | def create_datagram_endpoint(self, protocol_factory, |
| 388 | local_addr=None, remote_addr=None, *, |
| 389 | family=0, proto=0, flags=0): |
| 390 | """Create datagram connection.""" |
| 391 | if not (local_addr or remote_addr): |
| 392 | if family == 0: |
| 393 | raise ValueError('unexpected address family') |
| 394 | addr_pairs_info = (((family, proto), (None, None)),) |
| 395 | else: |
| 396 | # join addresss by (family, protocol) |
| 397 | addr_infos = collections.OrderedDict() |
| 398 | for idx, addr in ((0, local_addr), (1, remote_addr)): |
| 399 | if addr is not None: |
| 400 | assert isinstance(addr, tuple) and len(addr) == 2, ( |
| 401 | '2-tuple is expected') |
| 402 | |
| 403 | infos = yield from self.getaddrinfo( |
| 404 | *addr, family=family, type=socket.SOCK_DGRAM, |
| 405 | proto=proto, flags=flags) |
| 406 | if not infos: |
| 407 | raise OSError('getaddrinfo() returned empty list') |
| 408 | |
| 409 | for fam, _, pro, _, address in infos: |
| 410 | key = (fam, pro) |
| 411 | if key not in addr_infos: |
| 412 | addr_infos[key] = [None, None] |
| 413 | addr_infos[key][idx] = address |
| 414 | |
| 415 | # each addr has to have info for each (family, proto) pair |
| 416 | addr_pairs_info = [ |
| 417 | (key, addr_pair) for key, addr_pair in addr_infos.items() |
| 418 | if not ((local_addr and addr_pair[0] is None) or |
| 419 | (remote_addr and addr_pair[1] is None))] |
| 420 | |
| 421 | if not addr_pairs_info: |
| 422 | raise ValueError('can not get address information') |
| 423 | |
| 424 | exceptions = [] |
| 425 | |
| 426 | for ((family, proto), |
| 427 | (local_address, remote_address)) in addr_pairs_info: |
| 428 | sock = None |
| 429 | r_addr = None |
| 430 | try: |
| 431 | sock = socket.socket( |
| 432 | family=family, type=socket.SOCK_DGRAM, proto=proto) |
| 433 | sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) |
| 434 | sock.setblocking(False) |
| 435 | |
| 436 | if local_addr: |
| 437 | sock.bind(local_address) |
| 438 | if remote_addr: |
| 439 | yield from self.sock_connect(sock, remote_address) |
| 440 | r_addr = remote_address |
| 441 | except OSError as exc: |
| 442 | if sock is not None: |
| 443 | sock.close() |
| 444 | exceptions.append(exc) |
| 445 | else: |
| 446 | break |
| 447 | else: |
| 448 | raise exceptions[0] |
| 449 | |
| 450 | protocol = protocol_factory() |
| 451 | transport = self._make_datagram_transport(sock, protocol, r_addr) |
| 452 | return transport, protocol |
| 453 | |
| 454 | @tasks.coroutine |
| 455 | def create_server(self, protocol_factory, host=None, port=None, |
| 456 | *, |
| 457 | family=socket.AF_UNSPEC, |
| 458 | flags=socket.AI_PASSIVE, |
| 459 | sock=None, |
| 460 | backlog=100, |
| 461 | ssl=None, |
| 462 | reuse_address=None): |
| 463 | """XXX""" |
| 464 | if host is not None or port is not None: |
| 465 | if sock is not None: |
| 466 | raise ValueError( |
| 467 | 'host/port and sock can not be specified at the same time') |
| 468 | |
| 469 | AF_INET6 = getattr(socket, 'AF_INET6', 0) |
| 470 | if reuse_address is None: |
| 471 | reuse_address = os.name == 'posix' and sys.platform != 'cygwin' |
| 472 | sockets = [] |
| 473 | if host == '': |
| 474 | host = None |
| 475 | |
| 476 | infos = yield from self.getaddrinfo( |
| 477 | host, port, family=family, |
| 478 | type=socket.SOCK_STREAM, proto=0, flags=flags) |
| 479 | if not infos: |
| 480 | raise OSError('getaddrinfo() returned empty list') |
| 481 | |
| 482 | completed = False |
| 483 | try: |
| 484 | for res in infos: |
| 485 | af, socktype, proto, canonname, sa = res |
Guido van Rossum | 32e4685 | 2013-10-19 17:04:25 -0700 | [diff] [blame] | 486 | try: |
| 487 | sock = socket.socket(af, socktype, proto) |
| 488 | except socket.error: |
| 489 | # Assume it's a bad family/type/protocol combination. |
| 490 | continue |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 491 | sockets.append(sock) |
| 492 | if reuse_address: |
| 493 | sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, |
| 494 | True) |
| 495 | # Disable IPv4/IPv6 dual stack support (enabled by |
| 496 | # default on Linux) which makes a single socket |
| 497 | # listen on both address families. |
| 498 | if af == AF_INET6 and hasattr(socket, 'IPPROTO_IPV6'): |
| 499 | sock.setsockopt(socket.IPPROTO_IPV6, |
| 500 | socket.IPV6_V6ONLY, |
| 501 | True) |
| 502 | try: |
| 503 | sock.bind(sa) |
| 504 | except OSError as err: |
| 505 | raise OSError(err.errno, 'error while attempting ' |
| 506 | 'to bind on address %r: %s' |
| 507 | % (sa, err.strerror.lower())) |
| 508 | completed = True |
| 509 | finally: |
| 510 | if not completed: |
| 511 | for sock in sockets: |
| 512 | sock.close() |
| 513 | else: |
| 514 | if sock is None: |
| 515 | raise ValueError( |
| 516 | 'host and port was not specified and no sock specified') |
| 517 | sockets = [sock] |
| 518 | |
| 519 | server = Server(self, sockets) |
| 520 | for sock in sockets: |
| 521 | sock.listen(backlog) |
| 522 | sock.setblocking(False) |
| 523 | self._start_serving(protocol_factory, sock, ssl, server) |
| 524 | return server |
| 525 | |
| 526 | @tasks.coroutine |
| 527 | def connect_read_pipe(self, protocol_factory, pipe): |
| 528 | protocol = protocol_factory() |
| 529 | waiter = futures.Future(loop=self) |
| 530 | transport = self._make_read_pipe_transport(pipe, protocol, waiter) |
| 531 | yield from waiter |
| 532 | return transport, protocol |
| 533 | |
| 534 | @tasks.coroutine |
| 535 | def connect_write_pipe(self, protocol_factory, pipe): |
| 536 | protocol = protocol_factory() |
| 537 | waiter = futures.Future(loop=self) |
| 538 | transport = self._make_write_pipe_transport(pipe, protocol, waiter) |
| 539 | yield from waiter |
| 540 | return transport, protocol |
| 541 | |
| 542 | @tasks.coroutine |
| 543 | def subprocess_shell(self, protocol_factory, cmd, *, stdin=subprocess.PIPE, |
| 544 | stdout=subprocess.PIPE, stderr=subprocess.PIPE, |
| 545 | universal_newlines=False, shell=True, bufsize=0, |
| 546 | **kwargs): |
| 547 | assert not universal_newlines, "universal_newlines must be False" |
| 548 | assert shell, "shell must be True" |
| 549 | assert isinstance(cmd, str), cmd |
| 550 | protocol = protocol_factory() |
| 551 | transport = yield from self._make_subprocess_transport( |
| 552 | protocol, cmd, True, stdin, stdout, stderr, bufsize, **kwargs) |
| 553 | return transport, protocol |
| 554 | |
| 555 | @tasks.coroutine |
| 556 | def subprocess_exec(self, protocol_factory, *args, stdin=subprocess.PIPE, |
| 557 | stdout=subprocess.PIPE, stderr=subprocess.PIPE, |
| 558 | universal_newlines=False, shell=False, bufsize=0, |
| 559 | **kwargs): |
| 560 | assert not universal_newlines, "universal_newlines must be False" |
| 561 | assert not shell, "shell must be False" |
| 562 | protocol = protocol_factory() |
| 563 | transport = yield from self._make_subprocess_transport( |
| 564 | protocol, args, False, stdin, stdout, stderr, bufsize, **kwargs) |
| 565 | return transport, protocol |
| 566 | |
| 567 | def _add_callback(self, handle): |
| 568 | """Add a Handle to ready or scheduled.""" |
| 569 | assert isinstance(handle, events.Handle), 'A Handle is required here' |
| 570 | if handle._cancelled: |
| 571 | return |
| 572 | if isinstance(handle, events.TimerHandle): |
| 573 | heapq.heappush(self._scheduled, handle) |
| 574 | else: |
| 575 | self._ready.append(handle) |
| 576 | |
| 577 | def _add_callback_signalsafe(self, handle): |
| 578 | """Like _add_callback() but called from a signal handler.""" |
| 579 | self._add_callback(handle) |
| 580 | self._write_to_self() |
| 581 | |
| 582 | def _run_once(self): |
| 583 | """Run one full iteration of the event loop. |
| 584 | |
| 585 | This calls all currently ready callbacks, polls for I/O, |
| 586 | schedules the resulting callbacks, and finally schedules |
| 587 | 'call_later' callbacks. |
| 588 | """ |
| 589 | # Remove delayed calls that were cancelled from head of queue. |
| 590 | while self._scheduled and self._scheduled[0]._cancelled: |
| 591 | heapq.heappop(self._scheduled) |
| 592 | |
| 593 | timeout = None |
| 594 | if self._ready: |
| 595 | timeout = 0 |
| 596 | elif self._scheduled: |
| 597 | # Compute the desired timeout. |
| 598 | when = self._scheduled[0]._when |
| 599 | deadline = max(0, when - self.time()) |
| 600 | if timeout is None: |
| 601 | timeout = deadline |
| 602 | else: |
| 603 | timeout = min(timeout, deadline) |
| 604 | |
| 605 | # TODO: Instrumentation only in debug mode? |
| 606 | t0 = self.time() |
| 607 | event_list = self._selector.select(timeout) |
| 608 | t1 = self.time() |
| 609 | argstr = '' if timeout is None else '{:.3f}'.format(timeout) |
| 610 | if t1-t0 >= 1: |
| 611 | level = logging.INFO |
| 612 | else: |
| 613 | level = logging.DEBUG |
Guido van Rossum | fc29e0f | 2013-10-17 15:39:45 -0700 | [diff] [blame] | 614 | logger.log(level, 'poll%s took %.3f seconds', argstr, t1-t0) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 615 | self._process_events(event_list) |
| 616 | |
| 617 | # Handle 'later' callbacks that are ready. |
| 618 | now = self.time() |
| 619 | while self._scheduled: |
| 620 | handle = self._scheduled[0] |
| 621 | if handle._when > now: |
| 622 | break |
| 623 | handle = heapq.heappop(self._scheduled) |
| 624 | self._ready.append(handle) |
| 625 | |
| 626 | # This is the only place where callbacks are actually *called*. |
| 627 | # All other places just add them to ready. |
| 628 | # Note: We run all currently scheduled callbacks, but not any |
| 629 | # callbacks scheduled by callbacks run this time around -- |
| 630 | # they will be run the next time (after another I/O poll). |
| 631 | # Use an idiom that is threadsafe without using locks. |
| 632 | ntodo = len(self._ready) |
| 633 | for i in range(ntodo): |
| 634 | handle = self._ready.popleft() |
| 635 | if not handle._cancelled: |
| 636 | handle._run() |
| 637 | handle = None # Needed to break cycles when an exception occurs. |