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"""The asyncio package, tracking PEP 3156."""
# flake8: noqa
import sys
# This relies on each of the submodules having an __all__ variable.
from .base_events import *
from .coroutines import *
from .events import *
from .exceptions import *
from .futures import *
from .locks import *
from .protocols import *
from .runners import *
from .queues import *
from .streams import *
from .subprocess import *
from .tasks import *
from .threads import *
from .transports import *
# Exposed for _asynciomodule.c to implement now deprecated
# Task.all_tasks() method. This function will be removed in 3.9.
from .tasks import _all_tasks_compat # NoQA
__all__ = (base_events.__all__ +
coroutines.__all__ +
events.__all__ +
exceptions.__all__ +
futures.__all__ +
locks.__all__ +
protocols.__all__ +
runners.__all__ +
queues.__all__ +
streams.__all__ +
subprocess.__all__ +
tasks.__all__ +
threads.__all__ +
transports.__all__)
if sys.platform == 'win32': # pragma: no cover
from .windows_events import *
__all__ += windows_events.__all__
else:
from .unix_events import * # pragma: no cover
__all__ += unix_events.__all__

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import ast
import asyncio
import code
import concurrent.futures
import inspect
import sys
import threading
import types
import warnings
from . import futures
class AsyncIOInteractiveConsole(code.InteractiveConsole):
def __init__(self, locals, loop):
super().__init__(locals)
self.compile.compiler.flags |= ast.PyCF_ALLOW_TOP_LEVEL_AWAIT
self.loop = loop
def runcode(self, code):
future = concurrent.futures.Future()
def callback():
global repl_future
global repl_future_interrupted
repl_future = None
repl_future_interrupted = False
func = types.FunctionType(code, self.locals)
try:
coro = func()
except SystemExit:
raise
except KeyboardInterrupt as ex:
repl_future_interrupted = True
future.set_exception(ex)
return
except BaseException as ex:
future.set_exception(ex)
return
if not inspect.iscoroutine(coro):
future.set_result(coro)
return
try:
repl_future = self.loop.create_task(coro)
futures._chain_future(repl_future, future)
except BaseException as exc:
future.set_exception(exc)
loop.call_soon_threadsafe(callback)
try:
return future.result()
except SystemExit:
raise
except BaseException:
if repl_future_interrupted:
self.write("\nKeyboardInterrupt\n")
else:
self.showtraceback()
class REPLThread(threading.Thread):
def run(self):
try:
banner = (
f'asyncio REPL {sys.version} on {sys.platform}\n'
f'Use "await" directly instead of "asyncio.run()".\n'
f'Type "help", "copyright", "credits" or "license" '
f'for more information.\n'
f'{getattr(sys, "ps1", ">>> ")}import asyncio'
)
console.interact(
banner=banner,
exitmsg='exiting asyncio REPL...')
finally:
warnings.filterwarnings(
'ignore',
message=r'^coroutine .* was never awaited$',
category=RuntimeWarning)
loop.call_soon_threadsafe(loop.stop)
if __name__ == '__main__':
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
repl_locals = {'asyncio': asyncio}
for key in {'__name__', '__package__',
'__loader__', '__spec__',
'__builtins__', '__file__'}:
repl_locals[key] = locals()[key]
console = AsyncIOInteractiveConsole(repl_locals, loop)
repl_future = None
repl_future_interrupted = False
try:
import readline # NoQA
except ImportError:
pass
repl_thread = REPLThread()
repl_thread.daemon = True
repl_thread.start()
while True:
try:
loop.run_forever()
except KeyboardInterrupt:
if repl_future and not repl_future.done():
repl_future.cancel()
repl_future_interrupted = True
continue
else:
break

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__all__ = ()
import reprlib
from _thread import get_ident
from . import format_helpers
# States for Future.
_PENDING = 'PENDING'
_CANCELLED = 'CANCELLED'
_FINISHED = 'FINISHED'
def isfuture(obj):
"""Check for a Future.
This returns True when obj is a Future instance or is advertising
itself as duck-type compatible by setting _asyncio_future_blocking.
See comment in Future for more details.
"""
return (hasattr(obj.__class__, '_asyncio_future_blocking') and
obj._asyncio_future_blocking is not None)
def _format_callbacks(cb):
"""helper function for Future.__repr__"""
size = len(cb)
if not size:
cb = ''
def format_cb(callback):
return format_helpers._format_callback_source(callback, ())
if size == 1:
cb = format_cb(cb[0][0])
elif size == 2:
cb = '{}, {}'.format(format_cb(cb[0][0]), format_cb(cb[1][0]))
elif size > 2:
cb = '{}, <{} more>, {}'.format(format_cb(cb[0][0]),
size - 2,
format_cb(cb[-1][0]))
return f'cb=[{cb}]'
# bpo-42183: _repr_running is needed for repr protection
# when a Future or Task result contains itself directly or indirectly.
# The logic is borrowed from @reprlib.recursive_repr decorator.
# Unfortunately, the direct decorator usage is impossible because of
# AttributeError: '_asyncio.Task' object has no attribute '__module__' error.
#
# After fixing this thing we can return to the decorator based approach.
_repr_running = set()
def _future_repr_info(future):
# (Future) -> str
"""helper function for Future.__repr__"""
info = [future._state.lower()]
if future._state == _FINISHED:
if future._exception is not None:
info.append(f'exception={future._exception!r}')
else:
key = id(future), get_ident()
if key in _repr_running:
result = '...'
else:
_repr_running.add(key)
try:
# use reprlib to limit the length of the output, especially
# for very long strings
result = reprlib.repr(future._result)
finally:
_repr_running.discard(key)
info.append(f'result={result}')
if future._callbacks:
info.append(_format_callbacks(future._callbacks))
if future._source_traceback:
frame = future._source_traceback[-1]
info.append(f'created at {frame[0]}:{frame[1]}')
return info

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import collections
import subprocess
import warnings
from . import protocols
from . import transports
from .log import logger
class BaseSubprocessTransport(transports.SubprocessTransport):
def __init__(self, loop, protocol, args, shell,
stdin, stdout, stderr, bufsize,
waiter=None, extra=None, **kwargs):
super().__init__(extra)
self._closed = False
self._protocol = protocol
self._loop = loop
self._proc = None
self._pid = None
self._returncode = None
self._exit_waiters = []
self._pending_calls = collections.deque()
self._pipes = {}
self._finished = False
if stdin == subprocess.PIPE:
self._pipes[0] = None
if stdout == subprocess.PIPE:
self._pipes[1] = None
if stderr == subprocess.PIPE:
self._pipes[2] = None
# Create the child process: set the _proc attribute
try:
self._start(args=args, shell=shell, stdin=stdin, stdout=stdout,
stderr=stderr, bufsize=bufsize, **kwargs)
except:
self.close()
raise
self._pid = self._proc.pid
self._extra['subprocess'] = self._proc
if self._loop.get_debug():
if isinstance(args, (bytes, str)):
program = args
else:
program = args[0]
logger.debug('process %r created: pid %s',
program, self._pid)
self._loop.create_task(self._connect_pipes(waiter))
def __repr__(self):
info = [self.__class__.__name__]
if self._closed:
info.append('closed')
if self._pid is not None:
info.append(f'pid={self._pid}')
if self._returncode is not None:
info.append(f'returncode={self._returncode}')
elif self._pid is not None:
info.append('running')
else:
info.append('not started')
stdin = self._pipes.get(0)
if stdin is not None:
info.append(f'stdin={stdin.pipe}')
stdout = self._pipes.get(1)
stderr = self._pipes.get(2)
if stdout is not None and stderr is stdout:
info.append(f'stdout=stderr={stdout.pipe}')
else:
if stdout is not None:
info.append(f'stdout={stdout.pipe}')
if stderr is not None:
info.append(f'stderr={stderr.pipe}')
return '<{}>'.format(' '.join(info))
def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
raise NotImplementedError
def set_protocol(self, protocol):
self._protocol = protocol
def get_protocol(self):
return self._protocol
def is_closing(self):
return self._closed
def close(self):
if self._closed:
return
self._closed = True
for proto in self._pipes.values():
if proto is None:
continue
proto.pipe.close()
if (self._proc is not None and
# has the child process finished?
self._returncode is None and
# the child process has finished, but the
# transport hasn't been notified yet?
self._proc.poll() is None):
if self._loop.get_debug():
logger.warning('Close running child process: kill %r', self)
try:
self._proc.kill()
except ProcessLookupError:
pass
# Don't clear the _proc reference yet: _post_init() may still run
def __del__(self, _warn=warnings.warn):
if not self._closed:
_warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
self.close()
def get_pid(self):
return self._pid
def get_returncode(self):
return self._returncode
def get_pipe_transport(self, fd):
if fd in self._pipes:
return self._pipes[fd].pipe
else:
return None
def _check_proc(self):
if self._proc is None:
raise ProcessLookupError()
def send_signal(self, signal):
self._check_proc()
self._proc.send_signal(signal)
def terminate(self):
self._check_proc()
self._proc.terminate()
def kill(self):
self._check_proc()
self._proc.kill()
async def _connect_pipes(self, waiter):
try:
proc = self._proc
loop = self._loop
if proc.stdin is not None:
_, pipe = await loop.connect_write_pipe(
lambda: WriteSubprocessPipeProto(self, 0),
proc.stdin)
self._pipes[0] = pipe
if proc.stdout is not None:
_, pipe = await loop.connect_read_pipe(
lambda: ReadSubprocessPipeProto(self, 1),
proc.stdout)
self._pipes[1] = pipe
if proc.stderr is not None:
_, pipe = await loop.connect_read_pipe(
lambda: ReadSubprocessPipeProto(self, 2),
proc.stderr)
self._pipes[2] = pipe
assert self._pending_calls is not None
loop.call_soon(self._protocol.connection_made, self)
for callback, data in self._pending_calls:
loop.call_soon(callback, *data)
self._pending_calls = None
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
if waiter is not None and not waiter.cancelled():
waiter.set_exception(exc)
else:
if waiter is not None and not waiter.cancelled():
waiter.set_result(None)
def _call(self, cb, *data):
if self._pending_calls is not None:
self._pending_calls.append((cb, data))
else:
self._loop.call_soon(cb, *data)
def _pipe_connection_lost(self, fd, exc):
self._call(self._protocol.pipe_connection_lost, fd, exc)
self._try_finish()
def _pipe_data_received(self, fd, data):
self._call(self._protocol.pipe_data_received, fd, data)
def _process_exited(self, returncode):
assert returncode is not None, returncode
assert self._returncode is None, self._returncode
if self._loop.get_debug():
logger.info('%r exited with return code %r', self, returncode)
self._returncode = returncode
if self._proc.returncode is None:
# asyncio uses a child watcher: copy the status into the Popen
# object. On Python 3.6, it is required to avoid a ResourceWarning.
self._proc.returncode = returncode
self._call(self._protocol.process_exited)
self._try_finish()
# wake up futures waiting for wait()
for waiter in self._exit_waiters:
if not waiter.cancelled():
waiter.set_result(returncode)
self._exit_waiters = None
async def _wait(self):
"""Wait until the process exit and return the process return code.
This method is a coroutine."""
if self._returncode is not None:
return self._returncode
waiter = self._loop.create_future()
self._exit_waiters.append(waiter)
return await waiter
def _try_finish(self):
assert not self._finished
if self._returncode is None:
return
if all(p is not None and p.disconnected
for p in self._pipes.values()):
self._finished = True
self._call(self._call_connection_lost, None)
def _call_connection_lost(self, exc):
try:
self._protocol.connection_lost(exc)
finally:
self._loop = None
self._proc = None
self._protocol = None
class WriteSubprocessPipeProto(protocols.BaseProtocol):
def __init__(self, proc, fd):
self.proc = proc
self.fd = fd
self.pipe = None
self.disconnected = False
def connection_made(self, transport):
self.pipe = transport
def __repr__(self):
return f'<{self.__class__.__name__} fd={self.fd} pipe={self.pipe!r}>'
def connection_lost(self, exc):
self.disconnected = True
self.proc._pipe_connection_lost(self.fd, exc)
self.proc = None
def pause_writing(self):
self.proc._protocol.pause_writing()
def resume_writing(self):
self.proc._protocol.resume_writing()
class ReadSubprocessPipeProto(WriteSubprocessPipeProto,
protocols.Protocol):
def data_received(self, data):
self.proc._pipe_data_received(self.fd, data)

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import linecache
import traceback
from . import base_futures
from . import coroutines
def _task_repr_info(task):
info = base_futures._future_repr_info(task)
if task._must_cancel:
# replace status
info[0] = 'cancelling'
info.insert(1, 'name=%r' % task.get_name())
coro = coroutines._format_coroutine(task._coro)
info.insert(2, f'coro=<{coro}>')
if task._fut_waiter is not None:
info.insert(3, f'wait_for={task._fut_waiter!r}')
return info
def _task_get_stack(task, limit):
frames = []
if hasattr(task._coro, 'cr_frame'):
# case 1: 'async def' coroutines
f = task._coro.cr_frame
elif hasattr(task._coro, 'gi_frame'):
# case 2: legacy coroutines
f = task._coro.gi_frame
elif hasattr(task._coro, 'ag_frame'):
# case 3: async generators
f = task._coro.ag_frame
else:
# case 4: unknown objects
f = None
if f is not None:
while f is not None:
if limit is not None:
if limit <= 0:
break
limit -= 1
frames.append(f)
f = f.f_back
frames.reverse()
elif task._exception is not None:
tb = task._exception.__traceback__
while tb is not None:
if limit is not None:
if limit <= 0:
break
limit -= 1
frames.append(tb.tb_frame)
tb = tb.tb_next
return frames
def _task_print_stack(task, limit, file):
extracted_list = []
checked = set()
for f in task.get_stack(limit=limit):
lineno = f.f_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
if filename not in checked:
checked.add(filename)
linecache.checkcache(filename)
line = linecache.getline(filename, lineno, f.f_globals)
extracted_list.append((filename, lineno, name, line))
exc = task._exception
if not extracted_list:
print(f'No stack for {task!r}', file=file)
elif exc is not None:
print(f'Traceback for {task!r} (most recent call last):', file=file)
else:
print(f'Stack for {task!r} (most recent call last):', file=file)
traceback.print_list(extracted_list, file=file)
if exc is not None:
for line in traceback.format_exception_only(exc.__class__, exc):
print(line, file=file, end='')

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import enum
# After the connection is lost, log warnings after this many write()s.
LOG_THRESHOLD_FOR_CONNLOST_WRITES = 5
# Seconds to wait before retrying accept().
ACCEPT_RETRY_DELAY = 1
# Number of stack entries to capture in debug mode.
# The larger the number, the slower the operation in debug mode
# (see extract_stack() in format_helpers.py).
DEBUG_STACK_DEPTH = 10
# Number of seconds to wait for SSL handshake to complete
# The default timeout matches that of Nginx.
SSL_HANDSHAKE_TIMEOUT = 60.0
# Used in sendfile fallback code. We use fallback for platforms
# that don't support sendfile, or for TLS connections.
SENDFILE_FALLBACK_READBUFFER_SIZE = 1024 * 256
# The enum should be here to break circular dependencies between
# base_events and sslproto
class _SendfileMode(enum.Enum):
UNSUPPORTED = enum.auto()
TRY_NATIVE = enum.auto()
FALLBACK = enum.auto()

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__all__ = 'coroutine', 'iscoroutinefunction', 'iscoroutine'
import collections.abc
import functools
import inspect
import os
import sys
import traceback
import types
import warnings
from . import base_futures
from . import constants
from . import format_helpers
from .log import logger
def _is_debug_mode():
# If you set _DEBUG to true, @coroutine will wrap the resulting
# generator objects in a CoroWrapper instance (defined below). That
# instance will log a message when the generator is never iterated
# over, which may happen when you forget to use "await" or "yield from"
# with a coroutine call.
# Note that the value of the _DEBUG flag is taken
# when the decorator is used, so to be of any use it must be set
# before you define your coroutines. A downside of using this feature
# is that tracebacks show entries for the CoroWrapper.__next__ method
# when _DEBUG is true.
return sys.flags.dev_mode or (not sys.flags.ignore_environment and
bool(os.environ.get('PYTHONASYNCIODEBUG')))
_DEBUG = _is_debug_mode()
class CoroWrapper:
# Wrapper for coroutine object in _DEBUG mode.
def __init__(self, gen, func=None):
assert inspect.isgenerator(gen) or inspect.iscoroutine(gen), gen
self.gen = gen
self.func = func # Used to unwrap @coroutine decorator
self._source_traceback = format_helpers.extract_stack(sys._getframe(1))
self.__name__ = getattr(gen, '__name__', None)
self.__qualname__ = getattr(gen, '__qualname__', None)
def __repr__(self):
coro_repr = _format_coroutine(self)
if self._source_traceback:
frame = self._source_traceback[-1]
coro_repr += f', created at {frame[0]}:{frame[1]}'
return f'<{self.__class__.__name__} {coro_repr}>'
def __iter__(self):
return self
def __next__(self):
return self.gen.send(None)
def send(self, value):
return self.gen.send(value)
def throw(self, type, value=None, traceback=None):
return self.gen.throw(type, value, traceback)
def close(self):
return self.gen.close()
@property
def gi_frame(self):
return self.gen.gi_frame
@property
def gi_running(self):
return self.gen.gi_running
@property
def gi_code(self):
return self.gen.gi_code
def __await__(self):
return self
@property
def gi_yieldfrom(self):
return self.gen.gi_yieldfrom
def __del__(self):
# Be careful accessing self.gen.frame -- self.gen might not exist.
gen = getattr(self, 'gen', None)
frame = getattr(gen, 'gi_frame', None)
if frame is not None and frame.f_lasti == -1:
msg = f'{self!r} was never yielded from'
tb = getattr(self, '_source_traceback', ())
if tb:
tb = ''.join(traceback.format_list(tb))
msg += (f'\nCoroutine object created at '
f'(most recent call last, truncated to '
f'{constants.DEBUG_STACK_DEPTH} last lines):\n')
msg += tb.rstrip()
logger.error(msg)
def coroutine(func):
"""Decorator to mark coroutines.
If the coroutine is not yielded from before it is destroyed,
an error message is logged.
"""
warnings.warn('"@coroutine" decorator is deprecated since Python 3.8, use "async def" instead',
DeprecationWarning,
stacklevel=2)
if inspect.iscoroutinefunction(func):
# In Python 3.5 that's all we need to do for coroutines
# defined with "async def".
return func
if inspect.isgeneratorfunction(func):
coro = func
else:
@functools.wraps(func)
def coro(*args, **kw):
res = func(*args, **kw)
if (base_futures.isfuture(res) or inspect.isgenerator(res) or
isinstance(res, CoroWrapper)):
res = yield from res
else:
# If 'res' is an awaitable, run it.
try:
await_meth = res.__await__
except AttributeError:
pass
else:
if isinstance(res, collections.abc.Awaitable):
res = yield from await_meth()
return res
coro = types.coroutine(coro)
if not _DEBUG:
wrapper = coro
else:
@functools.wraps(func)
def wrapper(*args, **kwds):
w = CoroWrapper(coro(*args, **kwds), func=func)
if w._source_traceback:
del w._source_traceback[-1]
# Python < 3.5 does not implement __qualname__
# on generator objects, so we set it manually.
# We use getattr as some callables (such as
# functools.partial may lack __qualname__).
w.__name__ = getattr(func, '__name__', None)
w.__qualname__ = getattr(func, '__qualname__', None)
return w
wrapper._is_coroutine = _is_coroutine # For iscoroutinefunction().
return wrapper
# A marker for iscoroutinefunction.
_is_coroutine = object()
def iscoroutinefunction(func):
"""Return True if func is a decorated coroutine function."""
return (inspect.iscoroutinefunction(func) or
getattr(func, '_is_coroutine', None) is _is_coroutine)
# Prioritize native coroutine check to speed-up
# asyncio.iscoroutine.
_COROUTINE_TYPES = (types.CoroutineType, types.GeneratorType,
collections.abc.Coroutine, CoroWrapper)
_iscoroutine_typecache = set()
def iscoroutine(obj):
"""Return True if obj is a coroutine object."""
if type(obj) in _iscoroutine_typecache:
return True
if isinstance(obj, _COROUTINE_TYPES):
# Just in case we don't want to cache more than 100
# positive types. That shouldn't ever happen, unless
# someone stressing the system on purpose.
if len(_iscoroutine_typecache) < 100:
_iscoroutine_typecache.add(type(obj))
return True
else:
return False
def _format_coroutine(coro):
assert iscoroutine(coro)
is_corowrapper = isinstance(coro, CoroWrapper)
def get_name(coro):
# Coroutines compiled with Cython sometimes don't have
# proper __qualname__ or __name__. While that is a bug
# in Cython, asyncio shouldn't crash with an AttributeError
# in its __repr__ functions.
if is_corowrapper:
return format_helpers._format_callback(coro.func, (), {})
if hasattr(coro, '__qualname__') and coro.__qualname__:
coro_name = coro.__qualname__
elif hasattr(coro, '__name__') and coro.__name__:
coro_name = coro.__name__
else:
# Stop masking Cython bugs, expose them in a friendly way.
coro_name = f'<{type(coro).__name__} without __name__>'
return f'{coro_name}()'
def is_running(coro):
try:
return coro.cr_running
except AttributeError:
try:
return coro.gi_running
except AttributeError:
return False
coro_code = None
if hasattr(coro, 'cr_code') and coro.cr_code:
coro_code = coro.cr_code
elif hasattr(coro, 'gi_code') and coro.gi_code:
coro_code = coro.gi_code
coro_name = get_name(coro)
if not coro_code:
# Built-in types might not have __qualname__ or __name__.
if is_running(coro):
return f'{coro_name} running'
else:
return coro_name
coro_frame = None
if hasattr(coro, 'gi_frame') and coro.gi_frame:
coro_frame = coro.gi_frame
elif hasattr(coro, 'cr_frame') and coro.cr_frame:
coro_frame = coro.cr_frame
# If Cython's coroutine has a fake code object without proper
# co_filename -- expose that.
filename = coro_code.co_filename or '<empty co_filename>'
lineno = 0
if (is_corowrapper and
coro.func is not None and
not inspect.isgeneratorfunction(coro.func)):
source = format_helpers._get_function_source(coro.func)
if source is not None:
filename, lineno = source
if coro_frame is None:
coro_repr = f'{coro_name} done, defined at {filename}:{lineno}'
else:
coro_repr = f'{coro_name} running, defined at {filename}:{lineno}'
elif coro_frame is not None:
lineno = coro_frame.f_lineno
coro_repr = f'{coro_name} running at {filename}:{lineno}'
else:
lineno = coro_code.co_firstlineno
coro_repr = f'{coro_name} done, defined at {filename}:{lineno}'
return coro_repr

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@ -0,0 +1,795 @@
"""Event loop and event loop policy."""
__all__ = (
'AbstractEventLoopPolicy',
'AbstractEventLoop', 'AbstractServer',
'Handle', 'TimerHandle',
'get_event_loop_policy', 'set_event_loop_policy',
'get_event_loop', 'set_event_loop', 'new_event_loop',
'get_child_watcher', 'set_child_watcher',
'_set_running_loop', 'get_running_loop',
'_get_running_loop',
)
import contextvars
import os
import socket
import subprocess
import sys
import threading
from . import format_helpers
class Handle:
"""Object returned by callback registration methods."""
__slots__ = ('_callback', '_args', '_cancelled', '_loop',
'_source_traceback', '_repr', '__weakref__',
'_context')
def __init__(self, callback, args, loop, context=None):
if context is None:
context = contextvars.copy_context()
self._context = context
self._loop = loop
self._callback = callback
self._args = args
self._cancelled = False
self._repr = None
if self._loop.get_debug():
self._source_traceback = format_helpers.extract_stack(
sys._getframe(1))
else:
self._source_traceback = None
def _repr_info(self):
info = [self.__class__.__name__]
if self._cancelled:
info.append('cancelled')
if self._callback is not None:
info.append(format_helpers._format_callback_source(
self._callback, self._args))
if self._source_traceback:
frame = self._source_traceback[-1]
info.append(f'created at {frame[0]}:{frame[1]}')
return info
def __repr__(self):
if self._repr is not None:
return self._repr
info = self._repr_info()
return '<{}>'.format(' '.join(info))
def cancel(self):
if not self._cancelled:
self._cancelled = True
if self._loop.get_debug():
# Keep a representation in debug mode to keep callback and
# parameters. For example, to log the warning
# "Executing <Handle...> took 2.5 second"
self._repr = repr(self)
self._callback = None
self._args = None
def cancelled(self):
return self._cancelled
def _run(self):
try:
self._context.run(self._callback, *self._args)
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
cb = format_helpers._format_callback_source(
self._callback, self._args)
msg = f'Exception in callback {cb}'
context = {
'message': msg,
'exception': exc,
'handle': self,
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
self = None # Needed to break cycles when an exception occurs.
class TimerHandle(Handle):
"""Object returned by timed callback registration methods."""
__slots__ = ['_scheduled', '_when']
def __init__(self, when, callback, args, loop, context=None):
assert when is not None
super().__init__(callback, args, loop, context)
if self._source_traceback:
del self._source_traceback[-1]
self._when = when
self._scheduled = False
def _repr_info(self):
info = super()._repr_info()
pos = 2 if self._cancelled else 1
info.insert(pos, f'when={self._when}')
return info
def __hash__(self):
return hash(self._when)
def __lt__(self, other):
if isinstance(other, TimerHandle):
return self._when < other._when
return NotImplemented
def __le__(self, other):
if isinstance(other, TimerHandle):
return self._when < other._when or self.__eq__(other)
return NotImplemented
def __gt__(self, other):
if isinstance(other, TimerHandle):
return self._when > other._when
return NotImplemented
def __ge__(self, other):
if isinstance(other, TimerHandle):
return self._when > other._when or self.__eq__(other)
return NotImplemented
def __eq__(self, other):
if isinstance(other, TimerHandle):
return (self._when == other._when and
self._callback == other._callback and
self._args == other._args and
self._cancelled == other._cancelled)
return NotImplemented
def cancel(self):
if not self._cancelled:
self._loop._timer_handle_cancelled(self)
super().cancel()
def when(self):
"""Return a scheduled callback time.
The time is an absolute timestamp, using the same time
reference as loop.time().
"""
return self._when
class AbstractServer:
"""Abstract server returned by create_server()."""
def close(self):
"""Stop serving. This leaves existing connections open."""
raise NotImplementedError
def get_loop(self):
"""Get the event loop the Server object is attached to."""
raise NotImplementedError
def is_serving(self):
"""Return True if the server is accepting connections."""
raise NotImplementedError
async def start_serving(self):
"""Start accepting connections.
This method is idempotent, so it can be called when
the server is already being serving.
"""
raise NotImplementedError
async def serve_forever(self):
"""Start accepting connections until the coroutine is cancelled.
The server is closed when the coroutine is cancelled.
"""
raise NotImplementedError
async def wait_closed(self):
"""Coroutine to wait until service is closed."""
raise NotImplementedError
async def __aenter__(self):
return self
async def __aexit__(self, *exc):
self.close()
await self.wait_closed()
class AbstractEventLoop:
"""Abstract event loop."""
# Running and stopping the event loop.
def run_forever(self):
"""Run the event loop until stop() is called."""
raise NotImplementedError
def run_until_complete(self, future):
"""Run the event loop until a Future is done.
Return the Future's result, or raise its exception.
"""
raise NotImplementedError
def stop(self):
"""Stop the event loop as soon as reasonable.
Exactly how soon that is may depend on the implementation, but
no more I/O callbacks should be scheduled.
"""
raise NotImplementedError
def is_running(self):
"""Return whether the event loop is currently running."""
raise NotImplementedError
def is_closed(self):
"""Returns True if the event loop was closed."""
raise NotImplementedError
def close(self):
"""Close the loop.
The loop should not be running.
This is idempotent and irreversible.
No other methods should be called after this one.
"""
raise NotImplementedError
async def shutdown_asyncgens(self):
"""Shutdown all active asynchronous generators."""
raise NotImplementedError
async def shutdown_default_executor(self):
"""Schedule the shutdown of the default executor."""
raise NotImplementedError
# Methods scheduling callbacks. All these return Handles.
def _timer_handle_cancelled(self, handle):
"""Notification that a TimerHandle has been cancelled."""
raise NotImplementedError
def call_soon(self, callback, *args):
return self.call_later(0, callback, *args)
def call_later(self, delay, callback, *args):
raise NotImplementedError
def call_at(self, when, callback, *args):
raise NotImplementedError
def time(self):
raise NotImplementedError
def create_future(self):
raise NotImplementedError
# Method scheduling a coroutine object: create a task.
def create_task(self, coro, *, name=None):
raise NotImplementedError
# Methods for interacting with threads.
def call_soon_threadsafe(self, callback, *args):
raise NotImplementedError
def run_in_executor(self, executor, func, *args):
raise NotImplementedError
def set_default_executor(self, executor):
raise NotImplementedError
# Network I/O methods returning Futures.
async def getaddrinfo(self, host, port, *,
family=0, type=0, proto=0, flags=0):
raise NotImplementedError
async def getnameinfo(self, sockaddr, flags=0):
raise NotImplementedError
async def create_connection(
self, protocol_factory, host=None, port=None,
*, ssl=None, family=0, proto=0,
flags=0, sock=None, local_addr=None,
server_hostname=None,
ssl_handshake_timeout=None,
happy_eyeballs_delay=None, interleave=None):
raise NotImplementedError
async def create_server(
self, protocol_factory, host=None, port=None,
*, family=socket.AF_UNSPEC,
flags=socket.AI_PASSIVE, sock=None, backlog=100,
ssl=None, reuse_address=None, reuse_port=None,
ssl_handshake_timeout=None,
start_serving=True):
"""A coroutine which creates a TCP server bound to host and port.
The return value is a Server object which can be used to stop
the service.
If host is an empty string or None all interfaces are assumed
and a list of multiple sockets will be returned (most likely
one for IPv4 and another one for IPv6). The host parameter can also be
a sequence (e.g. list) of hosts to bind to.
family can be set to either AF_INET or AF_INET6 to force the
socket to use IPv4 or IPv6. If not set it will be determined
from host (defaults to AF_UNSPEC).
flags is a bitmask for getaddrinfo().
sock can optionally be specified in order to use a preexisting
socket object.
backlog is the maximum number of queued connections passed to
listen() (defaults to 100).
ssl can be set to an SSLContext to enable SSL over the
accepted connections.
reuse_address tells the kernel to reuse a local socket in
TIME_WAIT state, without waiting for its natural timeout to
expire. If not specified will automatically be set to True on
UNIX.
reuse_port tells the kernel to allow this endpoint to be bound to
the same port as other existing endpoints are bound to, so long as
they all set this flag when being created. This option is not
supported on Windows.
ssl_handshake_timeout is the time in seconds that an SSL server
will wait for completion of the SSL handshake before aborting the
connection. Default is 60s.
start_serving set to True (default) causes the created server
to start accepting connections immediately. When set to False,
the user should await Server.start_serving() or Server.serve_forever()
to make the server to start accepting connections.
"""
raise NotImplementedError
async def sendfile(self, transport, file, offset=0, count=None,
*, fallback=True):
"""Send a file through a transport.
Return an amount of sent bytes.
"""
raise NotImplementedError
async def start_tls(self, transport, protocol, sslcontext, *,
server_side=False,
server_hostname=None,
ssl_handshake_timeout=None):
"""Upgrade a transport to TLS.
Return a new transport that *protocol* should start using
immediately.
"""
raise NotImplementedError
async def create_unix_connection(
self, protocol_factory, path=None, *,
ssl=None, sock=None,
server_hostname=None,
ssl_handshake_timeout=None):
raise NotImplementedError
async def create_unix_server(
self, protocol_factory, path=None, *,
sock=None, backlog=100, ssl=None,
ssl_handshake_timeout=None,
start_serving=True):
"""A coroutine which creates a UNIX Domain Socket server.
The return value is a Server object, which can be used to stop
the service.
path is a str, representing a file system path to bind the
server socket to.
sock can optionally be specified in order to use a preexisting
socket object.
backlog is the maximum number of queued connections passed to
listen() (defaults to 100).
ssl can be set to an SSLContext to enable SSL over the
accepted connections.
ssl_handshake_timeout is the time in seconds that an SSL server
will wait for the SSL handshake to complete (defaults to 60s).
start_serving set to True (default) causes the created server
to start accepting connections immediately. When set to False,
the user should await Server.start_serving() or Server.serve_forever()
to make the server to start accepting connections.
"""
raise NotImplementedError
async def create_datagram_endpoint(self, protocol_factory,
local_addr=None, remote_addr=None, *,
family=0, proto=0, flags=0,
reuse_address=None, reuse_port=None,
allow_broadcast=None, sock=None):
"""A coroutine which creates a datagram endpoint.
This method will try to establish the endpoint in the background.
When successful, the coroutine returns a (transport, protocol) pair.
protocol_factory must be a callable returning a protocol instance.
socket family AF_INET, socket.AF_INET6 or socket.AF_UNIX depending on
host (or family if specified), socket type SOCK_DGRAM.
reuse_address tells the kernel to reuse a local socket in
TIME_WAIT state, without waiting for its natural timeout to
expire. If not specified it will automatically be set to True on
UNIX.
reuse_port tells the kernel to allow this endpoint to be bound to
the same port as other existing endpoints are bound to, so long as
they all set this flag when being created. This option is not
supported on Windows and some UNIX's. If the
:py:data:`~socket.SO_REUSEPORT` constant is not defined then this
capability is unsupported.
allow_broadcast tells the kernel to allow this endpoint to send
messages to the broadcast address.
sock can optionally be specified in order to use a preexisting
socket object.
"""
raise NotImplementedError
# Pipes and subprocesses.
async def connect_read_pipe(self, protocol_factory, pipe):
"""Register read pipe in event loop. Set the pipe to non-blocking mode.
protocol_factory should instantiate object with Protocol interface.
pipe is a file-like object.
Return pair (transport, protocol), where transport supports the
ReadTransport interface."""
# The reason to accept file-like object instead of just file descriptor
# is: we need to own pipe and close it at transport finishing
# Can got complicated errors if pass f.fileno(),
# close fd in pipe transport then close f and vise versa.
raise NotImplementedError
async def connect_write_pipe(self, protocol_factory, pipe):
"""Register write pipe in event loop.
protocol_factory should instantiate object with BaseProtocol interface.
Pipe is file-like object already switched to nonblocking.
Return pair (transport, protocol), where transport support
WriteTransport interface."""
# The reason to accept file-like object instead of just file descriptor
# is: we need to own pipe and close it at transport finishing
# Can got complicated errors if pass f.fileno(),
# close fd in pipe transport then close f and vise versa.
raise NotImplementedError
async def subprocess_shell(self, protocol_factory, cmd, *,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
**kwargs):
raise NotImplementedError
async def subprocess_exec(self, protocol_factory, *args,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
**kwargs):
raise NotImplementedError
# Ready-based callback registration methods.
# The add_*() methods return None.
# The remove_*() methods return True if something was removed,
# False if there was nothing to delete.
def add_reader(self, fd, callback, *args):
raise NotImplementedError
def remove_reader(self, fd):
raise NotImplementedError
def add_writer(self, fd, callback, *args):
raise NotImplementedError
def remove_writer(self, fd):
raise NotImplementedError
# Completion based I/O methods returning Futures.
async def sock_recv(self, sock, nbytes):
raise NotImplementedError
async def sock_recv_into(self, sock, buf):
raise NotImplementedError
async def sock_sendall(self, sock, data):
raise NotImplementedError
async def sock_connect(self, sock, address):
raise NotImplementedError
async def sock_accept(self, sock):
raise NotImplementedError
async def sock_sendfile(self, sock, file, offset=0, count=None,
*, fallback=None):
raise NotImplementedError
# Signal handling.
def add_signal_handler(self, sig, callback, *args):
raise NotImplementedError
def remove_signal_handler(self, sig):
raise NotImplementedError
# Task factory.
def set_task_factory(self, factory):
raise NotImplementedError
def get_task_factory(self):
raise NotImplementedError
# Error handlers.
def get_exception_handler(self):
raise NotImplementedError
def set_exception_handler(self, handler):
raise NotImplementedError
def default_exception_handler(self, context):
raise NotImplementedError
def call_exception_handler(self, context):
raise NotImplementedError
# Debug flag management.
def get_debug(self):
raise NotImplementedError
def set_debug(self, enabled):
raise NotImplementedError
class AbstractEventLoopPolicy:
"""Abstract policy for accessing the event loop."""
def get_event_loop(self):
"""Get the event loop for the current context.
Returns an event loop object implementing the BaseEventLoop interface,
or raises an exception in case no event loop has been set for the
current context and the current policy does not specify to create one.
It should never return None."""
raise NotImplementedError
def set_event_loop(self, loop):
"""Set the event loop for the current context to loop."""
raise NotImplementedError
def new_event_loop(self):
"""Create and return a new event loop object according to this
policy's rules. If there's need to set this loop as the event loop for
the current context, set_event_loop must be called explicitly."""
raise NotImplementedError
# Child processes handling (Unix only).
def get_child_watcher(self):
"Get the watcher for child processes."
raise NotImplementedError
def set_child_watcher(self, watcher):
"""Set the watcher for child processes."""
raise NotImplementedError
class BaseDefaultEventLoopPolicy(AbstractEventLoopPolicy):
"""Default policy implementation for accessing the event loop.
In this policy, each thread has its own event loop. However, we
only automatically create an event loop by default for the main
thread; other threads by default have no event loop.
Other policies may have different rules (e.g. a single global
event loop, or automatically creating an event loop per thread, or
using some other notion of context to which an event loop is
associated).
"""
_loop_factory = None
class _Local(threading.local):
_loop = None
_set_called = False
def __init__(self):
self._local = self._Local()
def get_event_loop(self):
"""Get the event loop for the current context.
Returns an instance of EventLoop or raises an exception.
"""
if (self._local._loop is None and
not self._local._set_called and
threading.current_thread() is threading.main_thread()):
self.set_event_loop(self.new_event_loop())
if self._local._loop is None:
raise RuntimeError('There is no current event loop in thread %r.'
% threading.current_thread().name)
return self._local._loop
def set_event_loop(self, loop):
"""Set the event loop."""
self._local._set_called = True
assert loop is None or isinstance(loop, AbstractEventLoop)
self._local._loop = loop
def new_event_loop(self):
"""Create a new event loop.
You must call set_event_loop() to make this the current event
loop.
"""
return self._loop_factory()
# Event loop policy. The policy itself is always global, even if the
# policy's rules say that there is an event loop per thread (or other
# notion of context). The default policy is installed by the first
# call to get_event_loop_policy().
_event_loop_policy = None
# Lock for protecting the on-the-fly creation of the event loop policy.
_lock = threading.Lock()
# A TLS for the running event loop, used by _get_running_loop.
class _RunningLoop(threading.local):
loop_pid = (None, None)
_running_loop = _RunningLoop()
def get_running_loop():
"""Return the running event loop. Raise a RuntimeError if there is none.
This function is thread-specific.
"""
# NOTE: this function is implemented in C (see _asynciomodule.c)
loop = _get_running_loop()
if loop is None:
raise RuntimeError('no running event loop')
return loop
def _get_running_loop():
"""Return the running event loop or None.
This is a low-level function intended to be used by event loops.
This function is thread-specific.
"""
# NOTE: this function is implemented in C (see _asynciomodule.c)
running_loop, pid = _running_loop.loop_pid
if running_loop is not None and pid == os.getpid():
return running_loop
def _set_running_loop(loop):
"""Set the running event loop.
This is a low-level function intended to be used by event loops.
This function is thread-specific.
"""
# NOTE: this function is implemented in C (see _asynciomodule.c)
_running_loop.loop_pid = (loop, os.getpid())
def _init_event_loop_policy():
global _event_loop_policy
with _lock:
if _event_loop_policy is None: # pragma: no branch
from . import DefaultEventLoopPolicy
_event_loop_policy = DefaultEventLoopPolicy()
def get_event_loop_policy():
"""Get the current event loop policy."""
if _event_loop_policy is None:
_init_event_loop_policy()
return _event_loop_policy
def set_event_loop_policy(policy):
"""Set the current event loop policy.
If policy is None, the default policy is restored."""
global _event_loop_policy
assert policy is None or isinstance(policy, AbstractEventLoopPolicy)
_event_loop_policy = policy
def get_event_loop():
"""Return an asyncio event loop.
When called from a coroutine or a callback (e.g. scheduled with call_soon
or similar API), this function will always return the running event loop.
If there is no running event loop set, the function will return
the result of `get_event_loop_policy().get_event_loop()` call.
"""
# NOTE: this function is implemented in C (see _asynciomodule.c)
current_loop = _get_running_loop()
if current_loop is not None:
return current_loop
return get_event_loop_policy().get_event_loop()
def set_event_loop(loop):
"""Equivalent to calling get_event_loop_policy().set_event_loop(loop)."""
get_event_loop_policy().set_event_loop(loop)
def new_event_loop():
"""Equivalent to calling get_event_loop_policy().new_event_loop()."""
return get_event_loop_policy().new_event_loop()
def get_child_watcher():
"""Equivalent to calling get_event_loop_policy().get_child_watcher()."""
return get_event_loop_policy().get_child_watcher()
def set_child_watcher(watcher):
"""Equivalent to calling
get_event_loop_policy().set_child_watcher(watcher)."""
return get_event_loop_policy().set_child_watcher(watcher)
# Alias pure-Python implementations for testing purposes.
_py__get_running_loop = _get_running_loop
_py__set_running_loop = _set_running_loop
_py_get_running_loop = get_running_loop
_py_get_event_loop = get_event_loop
try:
# get_event_loop() is one of the most frequently called
# functions in asyncio. Pure Python implementation is
# about 4 times slower than C-accelerated.
from _asyncio import (_get_running_loop, _set_running_loop,
get_running_loop, get_event_loop)
except ImportError:
pass
else:
# Alias C implementations for testing purposes.
_c__get_running_loop = _get_running_loop
_c__set_running_loop = _set_running_loop
_c_get_running_loop = get_running_loop
_c_get_event_loop = get_event_loop

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@ -0,0 +1,58 @@
"""asyncio exceptions."""
__all__ = ('CancelledError', 'InvalidStateError', 'TimeoutError',
'IncompleteReadError', 'LimitOverrunError',
'SendfileNotAvailableError')
class CancelledError(BaseException):
"""The Future or Task was cancelled."""
class TimeoutError(Exception):
"""The operation exceeded the given deadline."""
class InvalidStateError(Exception):
"""The operation is not allowed in this state."""
class SendfileNotAvailableError(RuntimeError):
"""Sendfile syscall is not available.
Raised if OS does not support sendfile syscall for given socket or
file type.
"""
class IncompleteReadError(EOFError):
"""
Incomplete read error. Attributes:
- partial: read bytes string before the end of stream was reached
- expected: total number of expected bytes (or None if unknown)
"""
def __init__(self, partial, expected):
r_expected = 'undefined' if expected is None else repr(expected)
super().__init__(f'{len(partial)} bytes read on a total of '
f'{r_expected} expected bytes')
self.partial = partial
self.expected = expected
def __reduce__(self):
return type(self), (self.partial, self.expected)
class LimitOverrunError(Exception):
"""Reached the buffer limit while looking for a separator.
Attributes:
- consumed: total number of to be consumed bytes.
"""
def __init__(self, message, consumed):
super().__init__(message)
self.consumed = consumed
def __reduce__(self):
return type(self), (self.args[0], self.consumed)

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@ -0,0 +1,76 @@
import functools
import inspect
import reprlib
import sys
import traceback
from . import constants
def _get_function_source(func):
func = inspect.unwrap(func)
if inspect.isfunction(func):
code = func.__code__
return (code.co_filename, code.co_firstlineno)
if isinstance(func, functools.partial):
return _get_function_source(func.func)
if isinstance(func, functools.partialmethod):
return _get_function_source(func.func)
return None
def _format_callback_source(func, args):
func_repr = _format_callback(func, args, None)
source = _get_function_source(func)
if source:
func_repr += f' at {source[0]}:{source[1]}'
return func_repr
def _format_args_and_kwargs(args, kwargs):
"""Format function arguments and keyword arguments.
Special case for a single parameter: ('hello',) is formatted as ('hello').
"""
# use reprlib to limit the length of the output
items = []
if args:
items.extend(reprlib.repr(arg) for arg in args)
if kwargs:
items.extend(f'{k}={reprlib.repr(v)}' for k, v in kwargs.items())
return '({})'.format(', '.join(items))
def _format_callback(func, args, kwargs, suffix=''):
if isinstance(func, functools.partial):
suffix = _format_args_and_kwargs(args, kwargs) + suffix
return _format_callback(func.func, func.args, func.keywords, suffix)
if hasattr(func, '__qualname__') and func.__qualname__:
func_repr = func.__qualname__
elif hasattr(func, '__name__') and func.__name__:
func_repr = func.__name__
else:
func_repr = repr(func)
func_repr += _format_args_and_kwargs(args, kwargs)
if suffix:
func_repr += suffix
return func_repr
def extract_stack(f=None, limit=None):
"""Replacement for traceback.extract_stack() that only does the
necessary work for asyncio debug mode.
"""
if f is None:
f = sys._getframe().f_back
if limit is None:
# Limit the amount of work to a reasonable amount, as extract_stack()
# can be called for each coroutine and future in debug mode.
limit = constants.DEBUG_STACK_DEPTH
stack = traceback.StackSummary.extract(traceback.walk_stack(f),
limit=limit,
lookup_lines=False)
stack.reverse()
return stack

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@ -0,0 +1,423 @@
"""A Future class similar to the one in PEP 3148."""
__all__ = (
'Future', 'wrap_future', 'isfuture',
)
import concurrent.futures
import contextvars
import logging
import sys
from . import base_futures
from . import events
from . import exceptions
from . import format_helpers
isfuture = base_futures.isfuture
_PENDING = base_futures._PENDING
_CANCELLED = base_futures._CANCELLED
_FINISHED = base_futures._FINISHED
STACK_DEBUG = logging.DEBUG - 1 # heavy-duty debugging
class Future:
"""This class is *almost* compatible with concurrent.futures.Future.
Differences:
- This class is not thread-safe.
- result() and exception() do not take a timeout argument and
raise an exception when the future isn't done yet.
- Callbacks registered with add_done_callback() are always called
via the event loop's call_soon().
- This class is not compatible with the wait() and as_completed()
methods in the concurrent.futures package.
(In Python 3.4 or later we may be able to unify the implementations.)
"""
# Class variables serving as defaults for instance variables.
_state = _PENDING
_result = None
_exception = None
_loop = None
_source_traceback = None
_cancel_message = None
# A saved CancelledError for later chaining as an exception context.
_cancelled_exc = None
# This field is used for a dual purpose:
# - Its presence is a marker to declare that a class implements
# the Future protocol (i.e. is intended to be duck-type compatible).
# The value must also be not-None, to enable a subclass to declare
# that it is not compatible by setting this to None.
# - It is set by __iter__() below so that Task._step() can tell
# the difference between
# `await Future()` or`yield from Future()` (correct) vs.
# `yield Future()` (incorrect).
_asyncio_future_blocking = False
__log_traceback = False
def __init__(self, *, loop=None):
"""Initialize the future.
The optional event_loop argument allows explicitly setting the event
loop object used by the future. If it's not provided, the future uses
the default event loop.
"""
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
self._callbacks = []
if self._loop.get_debug():
self._source_traceback = format_helpers.extract_stack(
sys._getframe(1))
_repr_info = base_futures._future_repr_info
def __repr__(self):
return '<{} {}>'.format(self.__class__.__name__,
' '.join(self._repr_info()))
def __del__(self):
if not self.__log_traceback:
# set_exception() was not called, or result() or exception()
# has consumed the exception
return
exc = self._exception
context = {
'message':
f'{self.__class__.__name__} exception was never retrieved',
'exception': exc,
'future': self,
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
def __class_getitem__(cls, type):
return cls
@property
def _log_traceback(self):
return self.__log_traceback
@_log_traceback.setter
def _log_traceback(self, val):
if bool(val):
raise ValueError('_log_traceback can only be set to False')
self.__log_traceback = False
def get_loop(self):
"""Return the event loop the Future is bound to."""
loop = self._loop
if loop is None:
raise RuntimeError("Future object is not initialized.")
return loop
def _make_cancelled_error(self):
"""Create the CancelledError to raise if the Future is cancelled.
This should only be called once when handling a cancellation since
it erases the saved context exception value.
"""
if self._cancel_message is None:
exc = exceptions.CancelledError()
else:
exc = exceptions.CancelledError(self._cancel_message)
exc.__context__ = self._cancelled_exc
# Remove the reference since we don't need this anymore.
self._cancelled_exc = None
return exc
def cancel(self, msg=None):
"""Cancel the future and schedule callbacks.
If the future is already done or cancelled, return False. Otherwise,
change the future's state to cancelled, schedule the callbacks and
return True.
"""
self.__log_traceback = False
if self._state != _PENDING:
return False
self._state = _CANCELLED
self._cancel_message = msg
self.__schedule_callbacks()
return True
def __schedule_callbacks(self):
"""Internal: Ask the event loop to call all callbacks.
The callbacks are scheduled to be called as soon as possible. Also
clears the callback list.
"""
callbacks = self._callbacks[:]
if not callbacks:
return
self._callbacks[:] = []
for callback, ctx in callbacks:
self._loop.call_soon(callback, self, context=ctx)
def cancelled(self):
"""Return True if the future was cancelled."""
return self._state == _CANCELLED
# Don't implement running(); see http://bugs.python.org/issue18699
def done(self):
"""Return True if the future is done.
Done means either that a result / exception are available, or that the
future was cancelled.
"""
return self._state != _PENDING
def result(self):
"""Return the result this future represents.
If the future has been cancelled, raises CancelledError. If the
future's result isn't yet available, raises InvalidStateError. If
the future is done and has an exception set, this exception is raised.
"""
if self._state == _CANCELLED:
exc = self._make_cancelled_error()
raise exc
if self._state != _FINISHED:
raise exceptions.InvalidStateError('Result is not ready.')
self.__log_traceback = False
if self._exception is not None:
raise self._exception
return self._result
def exception(self):
"""Return the exception that was set on this future.
The exception (or None if no exception was set) is returned only if
the future is done. If the future has been cancelled, raises
CancelledError. If the future isn't done yet, raises
InvalidStateError.
"""
if self._state == _CANCELLED:
exc = self._make_cancelled_error()
raise exc
if self._state != _FINISHED:
raise exceptions.InvalidStateError('Exception is not set.')
self.__log_traceback = False
return self._exception
def add_done_callback(self, fn, *, context=None):
"""Add a callback to be run when the future becomes done.
The callback is called with a single argument - the future object. If
the future is already done when this is called, the callback is
scheduled with call_soon.
"""
if self._state != _PENDING:
self._loop.call_soon(fn, self, context=context)
else:
if context is None:
context = contextvars.copy_context()
self._callbacks.append((fn, context))
# New method not in PEP 3148.
def remove_done_callback(self, fn):
"""Remove all instances of a callback from the "call when done" list.
Returns the number of callbacks removed.
"""
filtered_callbacks = [(f, ctx)
for (f, ctx) in self._callbacks
if f != fn]
removed_count = len(self._callbacks) - len(filtered_callbacks)
if removed_count:
self._callbacks[:] = filtered_callbacks
return removed_count
# So-called internal methods (note: no set_running_or_notify_cancel()).
def set_result(self, result):
"""Mark the future done and set its result.
If the future is already done when this method is called, raises
InvalidStateError.
"""
if self._state != _PENDING:
raise exceptions.InvalidStateError(f'{self._state}: {self!r}')
self._result = result
self._state = _FINISHED
self.__schedule_callbacks()
def set_exception(self, exception):
"""Mark the future done and set an exception.
If the future is already done when this method is called, raises
InvalidStateError.
"""
if self._state != _PENDING:
raise exceptions.InvalidStateError(f'{self._state}: {self!r}')
if isinstance(exception, type):
exception = exception()
if type(exception) is StopIteration:
raise TypeError("StopIteration interacts badly with generators "
"and cannot be raised into a Future")
self._exception = exception
self._state = _FINISHED
self.__schedule_callbacks()
self.__log_traceback = True
def __await__(self):
if not self.done():
self._asyncio_future_blocking = True
yield self # This tells Task to wait for completion.
if not self.done():
raise RuntimeError("await wasn't used with future")
return self.result() # May raise too.
__iter__ = __await__ # make compatible with 'yield from'.
# Needed for testing purposes.
_PyFuture = Future
def _get_loop(fut):
# Tries to call Future.get_loop() if it's available.
# Otherwise fallbacks to using the old '_loop' property.
try:
get_loop = fut.get_loop
except AttributeError:
pass
else:
return get_loop()
return fut._loop
def _set_result_unless_cancelled(fut, result):
"""Helper setting the result only if the future was not cancelled."""
if fut.cancelled():
return
fut.set_result(result)
def _convert_future_exc(exc):
exc_class = type(exc)
if exc_class is concurrent.futures.CancelledError:
return exceptions.CancelledError(*exc.args)
elif exc_class is concurrent.futures.TimeoutError:
return exceptions.TimeoutError(*exc.args)
elif exc_class is concurrent.futures.InvalidStateError:
return exceptions.InvalidStateError(*exc.args)
else:
return exc
def _set_concurrent_future_state(concurrent, source):
"""Copy state from a future to a concurrent.futures.Future."""
assert source.done()
if source.cancelled():
concurrent.cancel()
if not concurrent.set_running_or_notify_cancel():
return
exception = source.exception()
if exception is not None:
concurrent.set_exception(_convert_future_exc(exception))
else:
result = source.result()
concurrent.set_result(result)
def _copy_future_state(source, dest):
"""Internal helper to copy state from another Future.
The other Future may be a concurrent.futures.Future.
"""
assert source.done()
if dest.cancelled():
return
assert not dest.done()
if source.cancelled():
dest.cancel()
else:
exception = source.exception()
if exception is not None:
dest.set_exception(_convert_future_exc(exception))
else:
result = source.result()
dest.set_result(result)
def _chain_future(source, destination):
"""Chain two futures so that when one completes, so does the other.
The result (or exception) of source will be copied to destination.
If destination is cancelled, source gets cancelled too.
Compatible with both asyncio.Future and concurrent.futures.Future.
"""
if not isfuture(source) and not isinstance(source,
concurrent.futures.Future):
raise TypeError('A future is required for source argument')
if not isfuture(destination) and not isinstance(destination,
concurrent.futures.Future):
raise TypeError('A future is required for destination argument')
source_loop = _get_loop(source) if isfuture(source) else None
dest_loop = _get_loop(destination) if isfuture(destination) else None
def _set_state(future, other):
if isfuture(future):
_copy_future_state(other, future)
else:
_set_concurrent_future_state(future, other)
def _call_check_cancel(destination):
if destination.cancelled():
if source_loop is None or source_loop is dest_loop:
source.cancel()
else:
source_loop.call_soon_threadsafe(source.cancel)
def _call_set_state(source):
if (destination.cancelled() and
dest_loop is not None and dest_loop.is_closed()):
return
if dest_loop is None or dest_loop is source_loop:
_set_state(destination, source)
else:
dest_loop.call_soon_threadsafe(_set_state, destination, source)
destination.add_done_callback(_call_check_cancel)
source.add_done_callback(_call_set_state)
def wrap_future(future, *, loop=None):
"""Wrap concurrent.futures.Future object."""
if isfuture(future):
return future
assert isinstance(future, concurrent.futures.Future), \
f'concurrent.futures.Future is expected, got {future!r}'
if loop is None:
loop = events.get_event_loop()
new_future = loop.create_future()
_chain_future(future, new_future)
return new_future
try:
import _asyncio
except ImportError:
pass
else:
# _CFuture is needed for tests.
Future = _CFuture = _asyncio.Future

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@ -0,0 +1,451 @@
"""Synchronization primitives."""
__all__ = ('Lock', 'Event', 'Condition', 'Semaphore', 'BoundedSemaphore')
import collections
import warnings
from . import events
from . import exceptions
class _ContextManagerMixin:
async def __aenter__(self):
await self.acquire()
# We have no use for the "as ..." clause in the with
# statement for locks.
return None
async def __aexit__(self, exc_type, exc, tb):
self.release()
class Lock(_ContextManagerMixin):
"""Primitive lock objects.
A primitive lock is a synchronization primitive that is not owned
by a particular coroutine when locked. A primitive lock is in one
of two states, 'locked' or 'unlocked'.
It is created in the unlocked state. It has two basic methods,
acquire() and release(). When the state is unlocked, acquire()
changes the state to locked and returns immediately. When the
state is locked, acquire() blocks until a call to release() in
another coroutine changes it to unlocked, then the acquire() call
resets it to locked and returns. The release() method should only
be called in the locked state; it changes the state to unlocked
and returns immediately. If an attempt is made to release an
unlocked lock, a RuntimeError will be raised.
When more than one coroutine is blocked in acquire() waiting for
the state to turn to unlocked, only one coroutine proceeds when a
release() call resets the state to unlocked; first coroutine which
is blocked in acquire() is being processed.
acquire() is a coroutine and should be called with 'await'.
Locks also support the asynchronous context management protocol.
'async with lock' statement should be used.
Usage:
lock = Lock()
...
await lock.acquire()
try:
...
finally:
lock.release()
Context manager usage:
lock = Lock()
...
async with lock:
...
Lock objects can be tested for locking state:
if not lock.locked():
await lock.acquire()
else:
# lock is acquired
...
"""
def __init__(self, *, loop=None):
self._waiters = None
self._locked = False
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
def __repr__(self):
res = super().__repr__()
extra = 'locked' if self._locked else 'unlocked'
if self._waiters:
extra = f'{extra}, waiters:{len(self._waiters)}'
return f'<{res[1:-1]} [{extra}]>'
def locked(self):
"""Return True if lock is acquired."""
return self._locked
async def acquire(self):
"""Acquire a lock.
This method blocks until the lock is unlocked, then sets it to
locked and returns True.
"""
if (not self._locked and (self._waiters is None or
all(w.cancelled() for w in self._waiters))):
self._locked = True
return True
if self._waiters is None:
self._waiters = collections.deque()
fut = self._loop.create_future()
self._waiters.append(fut)
# Finally block should be called before the CancelledError
# handling as we don't want CancelledError to call
# _wake_up_first() and attempt to wake up itself.
try:
try:
await fut
finally:
self._waiters.remove(fut)
except exceptions.CancelledError:
if not self._locked:
self._wake_up_first()
raise
self._locked = True
return True
def release(self):
"""Release a lock.
When the lock is locked, reset it to unlocked, and return.
If any other coroutines are blocked waiting for the lock to become
unlocked, allow exactly one of them to proceed.
When invoked on an unlocked lock, a RuntimeError is raised.
There is no return value.
"""
if self._locked:
self._locked = False
self._wake_up_first()
else:
raise RuntimeError('Lock is not acquired.')
def _wake_up_first(self):
"""Wake up the first waiter if it isn't done."""
if not self._waiters:
return
try:
fut = next(iter(self._waiters))
except StopIteration:
return
# .done() necessarily means that a waiter will wake up later on and
# either take the lock, or, if it was cancelled and lock wasn't
# taken already, will hit this again and wake up a new waiter.
if not fut.done():
fut.set_result(True)
class Event:
"""Asynchronous equivalent to threading.Event.
Class implementing event objects. An event manages a flag that can be set
to true with the set() method and reset to false with the clear() method.
The wait() method blocks until the flag is true. The flag is initially
false.
"""
def __init__(self, *, loop=None):
self._waiters = collections.deque()
self._value = False
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
def __repr__(self):
res = super().__repr__()
extra = 'set' if self._value else 'unset'
if self._waiters:
extra = f'{extra}, waiters:{len(self._waiters)}'
return f'<{res[1:-1]} [{extra}]>'
def is_set(self):
"""Return True if and only if the internal flag is true."""
return self._value
def set(self):
"""Set the internal flag to true. All coroutines waiting for it to
become true are awakened. Coroutine that call wait() once the flag is
true will not block at all.
"""
if not self._value:
self._value = True
for fut in self._waiters:
if not fut.done():
fut.set_result(True)
def clear(self):
"""Reset the internal flag to false. Subsequently, coroutines calling
wait() will block until set() is called to set the internal flag
to true again."""
self._value = False
async def wait(self):
"""Block until the internal flag is true.
If the internal flag is true on entry, return True
immediately. Otherwise, block until another coroutine calls
set() to set the flag to true, then return True.
"""
if self._value:
return True
fut = self._loop.create_future()
self._waiters.append(fut)
try:
await fut
return True
finally:
self._waiters.remove(fut)
class Condition(_ContextManagerMixin):
"""Asynchronous equivalent to threading.Condition.
This class implements condition variable objects. A condition variable
allows one or more coroutines to wait until they are notified by another
coroutine.
A new Lock object is created and used as the underlying lock.
"""
def __init__(self, lock=None, *, loop=None):
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
if lock is None:
lock = Lock(loop=loop)
elif lock._loop is not self._loop:
raise ValueError("loop argument must agree with lock")
self._lock = lock
# Export the lock's locked(), acquire() and release() methods.
self.locked = lock.locked
self.acquire = lock.acquire
self.release = lock.release
self._waiters = collections.deque()
def __repr__(self):
res = super().__repr__()
extra = 'locked' if self.locked() else 'unlocked'
if self._waiters:
extra = f'{extra}, waiters:{len(self._waiters)}'
return f'<{res[1:-1]} [{extra}]>'
async def wait(self):
"""Wait until notified.
If the calling coroutine has not acquired the lock when this
method is called, a RuntimeError is raised.
This method releases the underlying lock, and then blocks
until it is awakened by a notify() or notify_all() call for
the same condition variable in another coroutine. Once
awakened, it re-acquires the lock and returns True.
"""
if not self.locked():
raise RuntimeError('cannot wait on un-acquired lock')
self.release()
try:
fut = self._loop.create_future()
self._waiters.append(fut)
try:
await fut
return True
finally:
self._waiters.remove(fut)
finally:
# Must reacquire lock even if wait is cancelled
cancelled = False
while True:
try:
await self.acquire()
break
except exceptions.CancelledError:
cancelled = True
if cancelled:
raise exceptions.CancelledError
async def wait_for(self, predicate):
"""Wait until a predicate becomes true.
The predicate should be a callable which result will be
interpreted as a boolean value. The final predicate value is
the return value.
"""
result = predicate()
while not result:
await self.wait()
result = predicate()
return result
def notify(self, n=1):
"""By default, wake up one coroutine waiting on this condition, if any.
If the calling coroutine has not acquired the lock when this method
is called, a RuntimeError is raised.
This method wakes up at most n of the coroutines waiting for the
condition variable; it is a no-op if no coroutines are waiting.
Note: an awakened coroutine does not actually return from its
wait() call until it can reacquire the lock. Since notify() does
not release the lock, its caller should.
"""
if not self.locked():
raise RuntimeError('cannot notify on un-acquired lock')
idx = 0
for fut in self._waiters:
if idx >= n:
break
if not fut.done():
idx += 1
fut.set_result(False)
def notify_all(self):
"""Wake up all threads waiting on this condition. This method acts
like notify(), but wakes up all waiting threads instead of one. If the
calling thread has not acquired the lock when this method is called,
a RuntimeError is raised.
"""
self.notify(len(self._waiters))
class Semaphore(_ContextManagerMixin):
"""A Semaphore implementation.
A semaphore manages an internal counter which is decremented by each
acquire() call and incremented by each release() call. The counter
can never go below zero; when acquire() finds that it is zero, it blocks,
waiting until some other thread calls release().
Semaphores also support the context management protocol.
The optional argument gives the initial value for the internal
counter; it defaults to 1. If the value given is less than 0,
ValueError is raised.
"""
def __init__(self, value=1, *, loop=None):
if value < 0:
raise ValueError("Semaphore initial value must be >= 0")
self._value = value
self._waiters = collections.deque()
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
def __repr__(self):
res = super().__repr__()
extra = 'locked' if self.locked() else f'unlocked, value:{self._value}'
if self._waiters:
extra = f'{extra}, waiters:{len(self._waiters)}'
return f'<{res[1:-1]} [{extra}]>'
def _wake_up_next(self):
while self._waiters:
waiter = self._waiters.popleft()
if not waiter.done():
waiter.set_result(None)
return
def locked(self):
"""Returns True if semaphore can not be acquired immediately."""
return self._value == 0
async def acquire(self):
"""Acquire a semaphore.
If the internal counter is larger than zero on entry,
decrement it by one and return True immediately. If it is
zero on entry, block, waiting until some other coroutine has
called release() to make it larger than 0, and then return
True.
"""
while self._value <= 0:
fut = self._loop.create_future()
self._waiters.append(fut)
try:
await fut
except:
# See the similar code in Queue.get.
fut.cancel()
if self._value > 0 and not fut.cancelled():
self._wake_up_next()
raise
self._value -= 1
return True
def release(self):
"""Release a semaphore, incrementing the internal counter by one.
When it was zero on entry and another coroutine is waiting for it to
become larger than zero again, wake up that coroutine.
"""
self._value += 1
self._wake_up_next()
class BoundedSemaphore(Semaphore):
"""A bounded semaphore implementation.
This raises ValueError in release() if it would increase the value
above the initial value.
"""
def __init__(self, value=1, *, loop=None):
if loop:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
self._bound_value = value
super().__init__(value, loop=loop)
def release(self):
if self._value >= self._bound_value:
raise ValueError('BoundedSemaphore released too many times')
super().release()

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"""Logging configuration."""
import logging
# Name the logger after the package.
logger = logging.getLogger(__package__)

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"""Event loop using a proactor and related classes.
A proactor is a "notify-on-completion" multiplexer. Currently a
proactor is only implemented on Windows with IOCP.
"""
__all__ = 'BaseProactorEventLoop',
import io
import os
import socket
import warnings
import signal
import threading
import collections
from . import base_events
from . import constants
from . import futures
from . import exceptions
from . import protocols
from . import sslproto
from . import transports
from . import trsock
from .log import logger
def _set_socket_extra(transport, sock):
transport._extra['socket'] = trsock.TransportSocket(sock)
try:
transport._extra['sockname'] = sock.getsockname()
except socket.error:
if transport._loop.get_debug():
logger.warning(
"getsockname() failed on %r", sock, exc_info=True)
if 'peername' not in transport._extra:
try:
transport._extra['peername'] = sock.getpeername()
except socket.error:
# UDP sockets may not have a peer name
transport._extra['peername'] = None
class _ProactorBasePipeTransport(transports._FlowControlMixin,
transports.BaseTransport):
"""Base class for pipe and socket transports."""
def __init__(self, loop, sock, protocol, waiter=None,
extra=None, server=None):
super().__init__(extra, loop)
self._set_extra(sock)
self._sock = sock
self.set_protocol(protocol)
self._server = server
self._buffer = None # None or bytearray.
self._read_fut = None
self._write_fut = None
self._pending_write = 0
self._conn_lost = 0
self._closing = False # Set when close() called.
self._eof_written = False
if self._server is not None:
self._server._attach()
self._loop.call_soon(self._protocol.connection_made, self)
if waiter is not None:
# only wake up the waiter when connection_made() has been called
self._loop.call_soon(futures._set_result_unless_cancelled,
waiter, None)
def __repr__(self):
info = [self.__class__.__name__]
if self._sock is None:
info.append('closed')
elif self._closing:
info.append('closing')
if self._sock is not None:
info.append(f'fd={self._sock.fileno()}')
if self._read_fut is not None:
info.append(f'read={self._read_fut!r}')
if self._write_fut is not None:
info.append(f'write={self._write_fut!r}')
if self._buffer:
info.append(f'write_bufsize={len(self._buffer)}')
if self._eof_written:
info.append('EOF written')
return '<{}>'.format(' '.join(info))
def _set_extra(self, sock):
self._extra['pipe'] = sock
def set_protocol(self, protocol):
self._protocol = protocol
def get_protocol(self):
return self._protocol
def is_closing(self):
return self._closing
def close(self):
if self._closing:
return
self._closing = True
self._conn_lost += 1
if not self._buffer and self._write_fut is None:
self._loop.call_soon(self._call_connection_lost, None)
if self._read_fut is not None:
self._read_fut.cancel()
self._read_fut = None
def __del__(self, _warn=warnings.warn):
if self._sock is not None:
_warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
self.close()
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
try:
if isinstance(exc, OSError):
if self._loop.get_debug():
logger.debug("%r: %s", self, message, exc_info=True)
else:
self._loop.call_exception_handler({
'message': message,
'exception': exc,
'transport': self,
'protocol': self._protocol,
})
finally:
self._force_close(exc)
def _force_close(self, exc):
if self._empty_waiter is not None and not self._empty_waiter.done():
if exc is None:
self._empty_waiter.set_result(None)
else:
self._empty_waiter.set_exception(exc)
if self._closing:
return
self._closing = True
self._conn_lost += 1
if self._write_fut:
self._write_fut.cancel()
self._write_fut = None
if self._read_fut:
self._read_fut.cancel()
self._read_fut = None
self._pending_write = 0
self._buffer = None
self._loop.call_soon(self._call_connection_lost, exc)
def _call_connection_lost(self, exc):
try:
self._protocol.connection_lost(exc)
finally:
# XXX If there is a pending overlapped read on the other
# end then it may fail with ERROR_NETNAME_DELETED if we
# just close our end. First calling shutdown() seems to
# cure it, but maybe using DisconnectEx() would be better.
if hasattr(self._sock, 'shutdown'):
self._sock.shutdown(socket.SHUT_RDWR)
self._sock.close()
self._sock = None
server = self._server
if server is not None:
server._detach()
self._server = None
def get_write_buffer_size(self):
size = self._pending_write
if self._buffer is not None:
size += len(self._buffer)
return size
class _ProactorReadPipeTransport(_ProactorBasePipeTransport,
transports.ReadTransport):
"""Transport for read pipes."""
def __init__(self, loop, sock, protocol, waiter=None,
extra=None, server=None):
self._pending_data = None
self._paused = True
super().__init__(loop, sock, protocol, waiter, extra, server)
self._loop.call_soon(self._loop_reading)
self._paused = False
def is_reading(self):
return not self._paused and not self._closing
def pause_reading(self):
if self._closing or self._paused:
return
self._paused = True
# bpo-33694: Don't cancel self._read_fut because cancelling an
# overlapped WSASend() loss silently data with the current proactor
# implementation.
#
# If CancelIoEx() fails with ERROR_NOT_FOUND, it means that WSASend()
# completed (even if HasOverlappedIoCompleted() returns 0), but
# Overlapped.cancel() currently silently ignores the ERROR_NOT_FOUND
# error. Once the overlapped is ignored, the IOCP loop will ignores the
# completion I/O event and so not read the result of the overlapped
# WSARecv().
if self._loop.get_debug():
logger.debug("%r pauses reading", self)
def resume_reading(self):
if self._closing or not self._paused:
return
self._paused = False
if self._read_fut is None:
self._loop.call_soon(self._loop_reading, None)
data = self._pending_data
self._pending_data = None
if data is not None:
# Call the protocol methode after calling _loop_reading(),
# since the protocol can decide to pause reading again.
self._loop.call_soon(self._data_received, data)
if self._loop.get_debug():
logger.debug("%r resumes reading", self)
def _eof_received(self):
if self._loop.get_debug():
logger.debug("%r received EOF", self)
try:
keep_open = self._protocol.eof_received()
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self._fatal_error(
exc, 'Fatal error: protocol.eof_received() call failed.')
return
if not keep_open:
self.close()
def _data_received(self, data):
if self._paused:
# Don't call any protocol method while reading is paused.
# The protocol will be called on resume_reading().
assert self._pending_data is None
self._pending_data = data
return
if not data:
self._eof_received()
return
if isinstance(self._protocol, protocols.BufferedProtocol):
try:
protocols._feed_data_to_buffered_proto(self._protocol, data)
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self._fatal_error(exc,
'Fatal error: protocol.buffer_updated() '
'call failed.')
return
else:
self._protocol.data_received(data)
def _loop_reading(self, fut=None):
data = None
try:
if fut is not None:
assert self._read_fut is fut or (self._read_fut is None and
self._closing)
self._read_fut = None
if fut.done():
# deliver data later in "finally" clause
data = fut.result()
else:
# the future will be replaced by next proactor.recv call
fut.cancel()
if self._closing:
# since close() has been called we ignore any read data
data = None
return
if data == b'':
# we got end-of-file so no need to reschedule a new read
return
# bpo-33694: buffer_updated() has currently no fast path because of
# a data loss issue caused by overlapped WSASend() cancellation.
if not self._paused:
# reschedule a new read
self._read_fut = self._loop._proactor.recv(self._sock, 32768)
except ConnectionAbortedError as exc:
if not self._closing:
self._fatal_error(exc, 'Fatal read error on pipe transport')
elif self._loop.get_debug():
logger.debug("Read error on pipe transport while closing",
exc_info=True)
except ConnectionResetError as exc:
self._force_close(exc)
except OSError as exc:
self._fatal_error(exc, 'Fatal read error on pipe transport')
except exceptions.CancelledError:
if not self._closing:
raise
else:
if not self._paused:
self._read_fut.add_done_callback(self._loop_reading)
finally:
if data is not None:
self._data_received(data)
class _ProactorBaseWritePipeTransport(_ProactorBasePipeTransport,
transports.WriteTransport):
"""Transport for write pipes."""
_start_tls_compatible = True
def __init__(self, *args, **kw):
super().__init__(*args, **kw)
self._empty_waiter = None
def write(self, data):
if not isinstance(data, (bytes, bytearray, memoryview)):
raise TypeError(
f"data argument must be a bytes-like object, "
f"not {type(data).__name__}")
if self._eof_written:
raise RuntimeError('write_eof() already called')
if self._empty_waiter is not None:
raise RuntimeError('unable to write; sendfile is in progress')
if not data:
return
if self._conn_lost:
if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
logger.warning('socket.send() raised exception.')
self._conn_lost += 1
return
# Observable states:
# 1. IDLE: _write_fut and _buffer both None
# 2. WRITING: _write_fut set; _buffer None
# 3. BACKED UP: _write_fut set; _buffer a bytearray
# We always copy the data, so the caller can't modify it
# while we're still waiting for the I/O to happen.
if self._write_fut is None: # IDLE -> WRITING
assert self._buffer is None
# Pass a copy, except if it's already immutable.
self._loop_writing(data=bytes(data))
elif not self._buffer: # WRITING -> BACKED UP
# Make a mutable copy which we can extend.
self._buffer = bytearray(data)
self._maybe_pause_protocol()
else: # BACKED UP
# Append to buffer (also copies).
self._buffer.extend(data)
self._maybe_pause_protocol()
def _loop_writing(self, f=None, data=None):
try:
if f is not None and self._write_fut is None and self._closing:
# XXX most likely self._force_close() has been called, and
# it has set self._write_fut to None.
return
assert f is self._write_fut
self._write_fut = None
self._pending_write = 0
if f:
f.result()
if data is None:
data = self._buffer
self._buffer = None
if not data:
if self._closing:
self._loop.call_soon(self._call_connection_lost, None)
if self._eof_written:
self._sock.shutdown(socket.SHUT_WR)
# Now that we've reduced the buffer size, tell the
# protocol to resume writing if it was paused. Note that
# we do this last since the callback is called immediately
# and it may add more data to the buffer (even causing the
# protocol to be paused again).
self._maybe_resume_protocol()
else:
self._write_fut = self._loop._proactor.send(self._sock, data)
if not self._write_fut.done():
assert self._pending_write == 0
self._pending_write = len(data)
self._write_fut.add_done_callback(self._loop_writing)
self._maybe_pause_protocol()
else:
self._write_fut.add_done_callback(self._loop_writing)
if self._empty_waiter is not None and self._write_fut is None:
self._empty_waiter.set_result(None)
except ConnectionResetError as exc:
self._force_close(exc)
except OSError as exc:
self._fatal_error(exc, 'Fatal write error on pipe transport')
def can_write_eof(self):
return True
def write_eof(self):
self.close()
def abort(self):
self._force_close(None)
def _make_empty_waiter(self):
if self._empty_waiter is not None:
raise RuntimeError("Empty waiter is already set")
self._empty_waiter = self._loop.create_future()
if self._write_fut is None:
self._empty_waiter.set_result(None)
return self._empty_waiter
def _reset_empty_waiter(self):
self._empty_waiter = None
class _ProactorWritePipeTransport(_ProactorBaseWritePipeTransport):
def __init__(self, *args, **kw):
super().__init__(*args, **kw)
self._read_fut = self._loop._proactor.recv(self._sock, 16)
self._read_fut.add_done_callback(self._pipe_closed)
def _pipe_closed(self, fut):
if fut.cancelled():
# the transport has been closed
return
assert fut.result() == b''
if self._closing:
assert self._read_fut is None
return
assert fut is self._read_fut, (fut, self._read_fut)
self._read_fut = None
if self._write_fut is not None:
self._force_close(BrokenPipeError())
else:
self.close()
class _ProactorDatagramTransport(_ProactorBasePipeTransport):
max_size = 256 * 1024
def __init__(self, loop, sock, protocol, address=None,
waiter=None, extra=None):
self._address = address
self._empty_waiter = None
# We don't need to call _protocol.connection_made() since our base
# constructor does it for us.
super().__init__(loop, sock, protocol, waiter=waiter, extra=extra)
# The base constructor sets _buffer = None, so we set it here
self._buffer = collections.deque()
self._loop.call_soon(self._loop_reading)
def _set_extra(self, sock):
_set_socket_extra(self, sock)
def get_write_buffer_size(self):
return sum(len(data) for data, _ in self._buffer)
def abort(self):
self._force_close(None)
def sendto(self, data, addr=None):
if not isinstance(data, (bytes, bytearray, memoryview)):
raise TypeError('data argument must be bytes-like object (%r)',
type(data))
if not data:
return
if self._address is not None and addr not in (None, self._address):
raise ValueError(
f'Invalid address: must be None or {self._address}')
if self._conn_lost and self._address:
if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
logger.warning('socket.sendto() raised exception.')
self._conn_lost += 1
return
# Ensure that what we buffer is immutable.
self._buffer.append((bytes(data), addr))
if self._write_fut is None:
# No current write operations are active, kick one off
self._loop_writing()
# else: A write operation is already kicked off
self._maybe_pause_protocol()
def _loop_writing(self, fut=None):
try:
if self._conn_lost:
return
assert fut is self._write_fut
self._write_fut = None
if fut:
# We are in a _loop_writing() done callback, get the result
fut.result()
if not self._buffer or (self._conn_lost and self._address):
# The connection has been closed
if self._closing:
self._loop.call_soon(self._call_connection_lost, None)
return
data, addr = self._buffer.popleft()
if self._address is not None:
self._write_fut = self._loop._proactor.send(self._sock,
data)
else:
self._write_fut = self._loop._proactor.sendto(self._sock,
data,
addr=addr)
except OSError as exc:
self._protocol.error_received(exc)
except Exception as exc:
self._fatal_error(exc, 'Fatal write error on datagram transport')
else:
self._write_fut.add_done_callback(self._loop_writing)
self._maybe_resume_protocol()
def _loop_reading(self, fut=None):
data = None
try:
if self._conn_lost:
return
assert self._read_fut is fut or (self._read_fut is None and
self._closing)
self._read_fut = None
if fut is not None:
res = fut.result()
if self._closing:
# since close() has been called we ignore any read data
data = None
return
if self._address is not None:
data, addr = res, self._address
else:
data, addr = res
if self._conn_lost:
return
if self._address is not None:
self._read_fut = self._loop._proactor.recv(self._sock,
self.max_size)
else:
self._read_fut = self._loop._proactor.recvfrom(self._sock,
self.max_size)
except OSError as exc:
self._protocol.error_received(exc)
except exceptions.CancelledError:
if not self._closing:
raise
else:
if self._read_fut is not None:
self._read_fut.add_done_callback(self._loop_reading)
finally:
if data:
self._protocol.datagram_received(data, addr)
class _ProactorDuplexPipeTransport(_ProactorReadPipeTransport,
_ProactorBaseWritePipeTransport,
transports.Transport):
"""Transport for duplex pipes."""
def can_write_eof(self):
return False
def write_eof(self):
raise NotImplementedError
class _ProactorSocketTransport(_ProactorReadPipeTransport,
_ProactorBaseWritePipeTransport,
transports.Transport):
"""Transport for connected sockets."""
_sendfile_compatible = constants._SendfileMode.TRY_NATIVE
def __init__(self, loop, sock, protocol, waiter=None,
extra=None, server=None):
super().__init__(loop, sock, protocol, waiter, extra, server)
base_events._set_nodelay(sock)
def _set_extra(self, sock):
_set_socket_extra(self, sock)
def can_write_eof(self):
return True
def write_eof(self):
if self._closing or self._eof_written:
return
self._eof_written = True
if self._write_fut is None:
self._sock.shutdown(socket.SHUT_WR)
class BaseProactorEventLoop(base_events.BaseEventLoop):
def __init__(self, proactor):
super().__init__()
logger.debug('Using proactor: %s', proactor.__class__.__name__)
self._proactor = proactor
self._selector = proactor # convenient alias
self._self_reading_future = None
self._accept_futures = {} # socket file descriptor => Future
proactor.set_loop(self)
self._make_self_pipe()
if threading.current_thread() is threading.main_thread():
# wakeup fd can only be installed to a file descriptor from the main thread
signal.set_wakeup_fd(self._csock.fileno())
def _make_socket_transport(self, sock, protocol, waiter=None,
extra=None, server=None):
return _ProactorSocketTransport(self, sock, protocol, waiter,
extra, server)
def _make_ssl_transport(
self, rawsock, protocol, sslcontext, waiter=None,
*, server_side=False, server_hostname=None,
extra=None, server=None,
ssl_handshake_timeout=None):
ssl_protocol = sslproto.SSLProtocol(
self, protocol, sslcontext, waiter,
server_side, server_hostname,
ssl_handshake_timeout=ssl_handshake_timeout)
_ProactorSocketTransport(self, rawsock, ssl_protocol,
extra=extra, server=server)
return ssl_protocol._app_transport
def _make_datagram_transport(self, sock, protocol,
address=None, waiter=None, extra=None):
return _ProactorDatagramTransport(self, sock, protocol, address,
waiter, extra)
def _make_duplex_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
return _ProactorDuplexPipeTransport(self,
sock, protocol, waiter, extra)
def _make_read_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
return _ProactorReadPipeTransport(self, sock, protocol, waiter, extra)
def _make_write_pipe_transport(self, sock, protocol, waiter=None,
extra=None):
# We want connection_lost() to be called when other end closes
return _ProactorWritePipeTransport(self,
sock, protocol, waiter, extra)
def close(self):
if self.is_running():
raise RuntimeError("Cannot close a running event loop")
if self.is_closed():
return
if threading.current_thread() is threading.main_thread():
signal.set_wakeup_fd(-1)
# Call these methods before closing the event loop (before calling
# BaseEventLoop.close), because they can schedule callbacks with
# call_soon(), which is forbidden when the event loop is closed.
self._stop_accept_futures()
self._close_self_pipe()
self._proactor.close()
self._proactor = None
self._selector = None
# Close the event loop
super().close()
async def sock_recv(self, sock, n):
return await self._proactor.recv(sock, n)
async def sock_recv_into(self, sock, buf):
return await self._proactor.recv_into(sock, buf)
async def sock_sendall(self, sock, data):
return await self._proactor.send(sock, data)
async def sock_connect(self, sock, address):
return await self._proactor.connect(sock, address)
async def sock_accept(self, sock):
return await self._proactor.accept(sock)
async def _sock_sendfile_native(self, sock, file, offset, count):
try:
fileno = file.fileno()
except (AttributeError, io.UnsupportedOperation) as err:
raise exceptions.SendfileNotAvailableError("not a regular file")
try:
fsize = os.fstat(fileno).st_size
except OSError:
raise exceptions.SendfileNotAvailableError("not a regular file")
blocksize = count if count else fsize
if not blocksize:
return 0 # empty file
blocksize = min(blocksize, 0xffff_ffff)
end_pos = min(offset + count, fsize) if count else fsize
offset = min(offset, fsize)
total_sent = 0
try:
while True:
blocksize = min(end_pos - offset, blocksize)
if blocksize <= 0:
return total_sent
await self._proactor.sendfile(sock, file, offset, blocksize)
offset += blocksize
total_sent += blocksize
finally:
if total_sent > 0:
file.seek(offset)
async def _sendfile_native(self, transp, file, offset, count):
resume_reading = transp.is_reading()
transp.pause_reading()
await transp._make_empty_waiter()
try:
return await self.sock_sendfile(transp._sock, file, offset, count,
fallback=False)
finally:
transp._reset_empty_waiter()
if resume_reading:
transp.resume_reading()
def _close_self_pipe(self):
if self._self_reading_future is not None:
self._self_reading_future.cancel()
self._self_reading_future = None
self._ssock.close()
self._ssock = None
self._csock.close()
self._csock = None
self._internal_fds -= 1
def _make_self_pipe(self):
# A self-socket, really. :-)
self._ssock, self._csock = socket.socketpair()
self._ssock.setblocking(False)
self._csock.setblocking(False)
self._internal_fds += 1
def _loop_self_reading(self, f=None):
try:
if f is not None:
f.result() # may raise
if self._self_reading_future is not f:
# When we scheduled this Future, we assigned it to
# _self_reading_future. If it's not there now, something has
# tried to cancel the loop while this callback was still in the
# queue (see windows_events.ProactorEventLoop.run_forever). In
# that case stop here instead of continuing to schedule a new
# iteration.
return
f = self._proactor.recv(self._ssock, 4096)
except exceptions.CancelledError:
# _close_self_pipe() has been called, stop waiting for data
return
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self.call_exception_handler({
'message': 'Error on reading from the event loop self pipe',
'exception': exc,
'loop': self,
})
else:
self._self_reading_future = f
f.add_done_callback(self._loop_self_reading)
def _write_to_self(self):
# This may be called from a different thread, possibly after
# _close_self_pipe() has been called or even while it is
# running. Guard for self._csock being None or closed. When
# a socket is closed, send() raises OSError (with errno set to
# EBADF, but let's not rely on the exact error code).
csock = self._csock
if csock is None:
return
try:
csock.send(b'\0')
except OSError:
if self._debug:
logger.debug("Fail to write a null byte into the "
"self-pipe socket",
exc_info=True)
def _start_serving(self, protocol_factory, sock,
sslcontext=None, server=None, backlog=100,
ssl_handshake_timeout=None):
def loop(f=None):
try:
if f is not None:
conn, addr = f.result()
if self._debug:
logger.debug("%r got a new connection from %r: %r",
server, addr, conn)
protocol = protocol_factory()
if sslcontext is not None:
self._make_ssl_transport(
conn, protocol, sslcontext, server_side=True,
extra={'peername': addr}, server=server,
ssl_handshake_timeout=ssl_handshake_timeout)
else:
self._make_socket_transport(
conn, protocol,
extra={'peername': addr}, server=server)
if self.is_closed():
return
f = self._proactor.accept(sock)
except OSError as exc:
if sock.fileno() != -1:
self.call_exception_handler({
'message': 'Accept failed on a socket',
'exception': exc,
'socket': trsock.TransportSocket(sock),
})
sock.close()
elif self._debug:
logger.debug("Accept failed on socket %r",
sock, exc_info=True)
except exceptions.CancelledError:
sock.close()
else:
self._accept_futures[sock.fileno()] = f
f.add_done_callback(loop)
self.call_soon(loop)
def _process_events(self, event_list):
# Events are processed in the IocpProactor._poll() method
pass
def _stop_accept_futures(self):
for future in self._accept_futures.values():
future.cancel()
self._accept_futures.clear()
def _stop_serving(self, sock):
future = self._accept_futures.pop(sock.fileno(), None)
if future:
future.cancel()
self._proactor._stop_serving(sock)
sock.close()

View File

@ -0,0 +1,220 @@
"""Abstract Protocol base classes."""
__all__ = (
'BaseProtocol', 'Protocol', 'DatagramProtocol',
'SubprocessProtocol', 'BufferedProtocol',
)
class BaseProtocol:
"""Common base class for protocol interfaces.
Usually user implements protocols that derived from BaseProtocol
like Protocol or ProcessProtocol.
The only case when BaseProtocol should be implemented directly is
write-only transport like write pipe
"""
__slots__ = ()
def connection_made(self, transport):
"""Called when a connection is made.
The argument is the transport representing the pipe connection.
To receive data, wait for data_received() calls.
When the connection is closed, connection_lost() is called.
"""
def connection_lost(self, exc):
"""Called when the connection is lost or closed.
The argument is an exception object or None (the latter
meaning a regular EOF is received or the connection was
aborted or closed).
"""
def pause_writing(self):
"""Called when the transport's buffer goes over the high-water mark.
Pause and resume calls are paired -- pause_writing() is called
once when the buffer goes strictly over the high-water mark
(even if subsequent writes increases the buffer size even
more), and eventually resume_writing() is called once when the
buffer size reaches the low-water mark.
Note that if the buffer size equals the high-water mark,
pause_writing() is not called -- it must go strictly over.
Conversely, resume_writing() is called when the buffer size is
equal or lower than the low-water mark. These end conditions
are important to ensure that things go as expected when either
mark is zero.
NOTE: This is the only Protocol callback that is not called
through EventLoop.call_soon() -- if it were, it would have no
effect when it's most needed (when the app keeps writing
without yielding until pause_writing() is called).
"""
def resume_writing(self):
"""Called when the transport's buffer drains below the low-water mark.
See pause_writing() for details.
"""
class Protocol(BaseProtocol):
"""Interface for stream protocol.
The user should implement this interface. They can inherit from
this class but don't need to. The implementations here do
nothing (they don't raise exceptions).
When the user wants to requests a transport, they pass a protocol
factory to a utility function (e.g., EventLoop.create_connection()).
When the connection is made successfully, connection_made() is
called with a suitable transport object. Then data_received()
will be called 0 or more times with data (bytes) received from the
transport; finally, connection_lost() will be called exactly once
with either an exception object or None as an argument.
State machine of calls:
start -> CM [-> DR*] [-> ER?] -> CL -> end
* CM: connection_made()
* DR: data_received()
* ER: eof_received()
* CL: connection_lost()
"""
__slots__ = ()
def data_received(self, data):
"""Called when some data is received.
The argument is a bytes object.
"""
def eof_received(self):
"""Called when the other end calls write_eof() or equivalent.
If this returns a false value (including None), the transport
will close itself. If it returns a true value, closing the
transport is up to the protocol.
"""
class BufferedProtocol(BaseProtocol):
"""Interface for stream protocol with manual buffer control.
Important: this has been added to asyncio in Python 3.7
*on a provisional basis*! Consider it as an experimental API that
might be changed or removed in Python 3.8.
Event methods, such as `create_server` and `create_connection`,
accept factories that return protocols that implement this interface.
The idea of BufferedProtocol is that it allows to manually allocate
and control the receive buffer. Event loops can then use the buffer
provided by the protocol to avoid unnecessary data copies. This
can result in noticeable performance improvement for protocols that
receive big amounts of data. Sophisticated protocols can allocate
the buffer only once at creation time.
State machine of calls:
start -> CM [-> GB [-> BU?]]* [-> ER?] -> CL -> end
* CM: connection_made()
* GB: get_buffer()
* BU: buffer_updated()
* ER: eof_received()
* CL: connection_lost()
"""
__slots__ = ()
def get_buffer(self, sizehint):
"""Called to allocate a new receive buffer.
*sizehint* is a recommended minimal size for the returned
buffer. When set to -1, the buffer size can be arbitrary.
Must return an object that implements the
:ref:`buffer protocol <bufferobjects>`.
It is an error to return a zero-sized buffer.
"""
def buffer_updated(self, nbytes):
"""Called when the buffer was updated with the received data.
*nbytes* is the total number of bytes that were written to
the buffer.
"""
def eof_received(self):
"""Called when the other end calls write_eof() or equivalent.
If this returns a false value (including None), the transport
will close itself. If it returns a true value, closing the
transport is up to the protocol.
"""
class DatagramProtocol(BaseProtocol):
"""Interface for datagram protocol."""
__slots__ = ()
def datagram_received(self, data, addr):
"""Called when some datagram is received."""
def error_received(self, exc):
"""Called when a send or receive operation raises an OSError.
(Other than BlockingIOError or InterruptedError.)
"""
class SubprocessProtocol(BaseProtocol):
"""Interface for protocol for subprocess calls."""
__slots__ = ()
def pipe_data_received(self, fd, data):
"""Called when the subprocess writes data into stdout/stderr pipe.
fd is int file descriptor.
data is bytes object.
"""
def pipe_connection_lost(self, fd, exc):
"""Called when a file descriptor associated with the child process is
closed.
fd is the int file descriptor that was closed.
"""
def process_exited(self):
"""Called when subprocess has exited."""
def _feed_data_to_buffered_proto(proto, data):
data_len = len(data)
while data_len:
buf = proto.get_buffer(data_len)
buf_len = len(buf)
if not buf_len:
raise RuntimeError('get_buffer() returned an empty buffer')
if buf_len >= data_len:
buf[:data_len] = data
proto.buffer_updated(data_len)
return
else:
buf[:buf_len] = data[:buf_len]
proto.buffer_updated(buf_len)
data = data[buf_len:]
data_len = len(data)

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__all__ = ('Queue', 'PriorityQueue', 'LifoQueue', 'QueueFull', 'QueueEmpty')
import collections
import heapq
import warnings
from . import events
from . import locks
class QueueEmpty(Exception):
"""Raised when Queue.get_nowait() is called on an empty Queue."""
pass
class QueueFull(Exception):
"""Raised when the Queue.put_nowait() method is called on a full Queue."""
pass
class Queue:
"""A queue, useful for coordinating producer and consumer coroutines.
If maxsize is less than or equal to zero, the queue size is infinite. If it
is an integer greater than 0, then "await put()" will block when the
queue reaches maxsize, until an item is removed by get().
Unlike the standard library Queue, you can reliably know this Queue's size
with qsize(), since your single-threaded asyncio application won't be
interrupted between calling qsize() and doing an operation on the Queue.
"""
def __init__(self, maxsize=0, *, loop=None):
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
self._maxsize = maxsize
# Futures.
self._getters = collections.deque()
# Futures.
self._putters = collections.deque()
self._unfinished_tasks = 0
self._finished = locks.Event(loop=loop)
self._finished.set()
self._init(maxsize)
# These three are overridable in subclasses.
def _init(self, maxsize):
self._queue = collections.deque()
def _get(self):
return self._queue.popleft()
def _put(self, item):
self._queue.append(item)
# End of the overridable methods.
def _wakeup_next(self, waiters):
# Wake up the next waiter (if any) that isn't cancelled.
while waiters:
waiter = waiters.popleft()
if not waiter.done():
waiter.set_result(None)
break
def __repr__(self):
return f'<{type(self).__name__} at {id(self):#x} {self._format()}>'
def __str__(self):
return f'<{type(self).__name__} {self._format()}>'
def __class_getitem__(cls, type):
return cls
def _format(self):
result = f'maxsize={self._maxsize!r}'
if getattr(self, '_queue', None):
result += f' _queue={list(self._queue)!r}'
if self._getters:
result += f' _getters[{len(self._getters)}]'
if self._putters:
result += f' _putters[{len(self._putters)}]'
if self._unfinished_tasks:
result += f' tasks={self._unfinished_tasks}'
return result
def qsize(self):
"""Number of items in the queue."""
return len(self._queue)
@property
def maxsize(self):
"""Number of items allowed in the queue."""
return self._maxsize
def empty(self):
"""Return True if the queue is empty, False otherwise."""
return not self._queue
def full(self):
"""Return True if there are maxsize items in the queue.
Note: if the Queue was initialized with maxsize=0 (the default),
then full() is never True.
"""
if self._maxsize <= 0:
return False
else:
return self.qsize() >= self._maxsize
async def put(self, item):
"""Put an item into the queue.
Put an item into the queue. If the queue is full, wait until a free
slot is available before adding item.
"""
while self.full():
putter = self._loop.create_future()
self._putters.append(putter)
try:
await putter
except:
putter.cancel() # Just in case putter is not done yet.
try:
# Clean self._putters from canceled putters.
self._putters.remove(putter)
except ValueError:
# The putter could be removed from self._putters by a
# previous get_nowait call.
pass
if not self.full() and not putter.cancelled():
# We were woken up by get_nowait(), but can't take
# the call. Wake up the next in line.
self._wakeup_next(self._putters)
raise
return self.put_nowait(item)
def put_nowait(self, item):
"""Put an item into the queue without blocking.
If no free slot is immediately available, raise QueueFull.
"""
if self.full():
raise QueueFull
self._put(item)
self._unfinished_tasks += 1
self._finished.clear()
self._wakeup_next(self._getters)
async def get(self):
"""Remove and return an item from the queue.
If queue is empty, wait until an item is available.
"""
while self.empty():
getter = self._loop.create_future()
self._getters.append(getter)
try:
await getter
except:
getter.cancel() # Just in case getter is not done yet.
try:
# Clean self._getters from canceled getters.
self._getters.remove(getter)
except ValueError:
# The getter could be removed from self._getters by a
# previous put_nowait call.
pass
if not self.empty() and not getter.cancelled():
# We were woken up by put_nowait(), but can't take
# the call. Wake up the next in line.
self._wakeup_next(self._getters)
raise
return self.get_nowait()
def get_nowait(self):
"""Remove and return an item from the queue.
Return an item if one is immediately available, else raise QueueEmpty.
"""
if self.empty():
raise QueueEmpty
item = self._get()
self._wakeup_next(self._putters)
return item
def task_done(self):
"""Indicate that a formerly enqueued task is complete.
Used by queue consumers. For each get() used to fetch a task,
a subsequent call to task_done() tells the queue that the processing
on the task is complete.
If a join() is currently blocking, it will resume when all items have
been processed (meaning that a task_done() call was received for every
item that had been put() into the queue).
Raises ValueError if called more times than there were items placed in
the queue.
"""
if self._unfinished_tasks <= 0:
raise ValueError('task_done() called too many times')
self._unfinished_tasks -= 1
if self._unfinished_tasks == 0:
self._finished.set()
async def join(self):
"""Block until all items in the queue have been gotten and processed.
The count of unfinished tasks goes up whenever an item is added to the
queue. The count goes down whenever a consumer calls task_done() to
indicate that the item was retrieved and all work on it is complete.
When the count of unfinished tasks drops to zero, join() unblocks.
"""
if self._unfinished_tasks > 0:
await self._finished.wait()
class PriorityQueue(Queue):
"""A subclass of Queue; retrieves entries in priority order (lowest first).
Entries are typically tuples of the form: (priority number, data).
"""
def _init(self, maxsize):
self._queue = []
def _put(self, item, heappush=heapq.heappush):
heappush(self._queue, item)
def _get(self, heappop=heapq.heappop):
return heappop(self._queue)
class LifoQueue(Queue):
"""A subclass of Queue that retrieves most recently added entries first."""
def _init(self, maxsize):
self._queue = []
def _put(self, item):
self._queue.append(item)
def _get(self):
return self._queue.pop()

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__all__ = 'run',
from . import coroutines
from . import events
from . import tasks
def run(main, *, debug=None):
"""Execute the coroutine and return the result.
This function runs the passed coroutine, taking care of
managing the asyncio event loop and finalizing asynchronous
generators.
This function cannot be called when another asyncio event loop is
running in the same thread.
If debug is True, the event loop will be run in debug mode.
This function always creates a new event loop and closes it at the end.
It should be used as a main entry point for asyncio programs, and should
ideally only be called once.
Example:
async def main():
await asyncio.sleep(1)
print('hello')
asyncio.run(main())
"""
if events._get_running_loop() is not None:
raise RuntimeError(
"asyncio.run() cannot be called from a running event loop")
if not coroutines.iscoroutine(main):
raise ValueError("a coroutine was expected, got {!r}".format(main))
loop = events.new_event_loop()
try:
events.set_event_loop(loop)
if debug is not None:
loop.set_debug(debug)
return loop.run_until_complete(main)
finally:
try:
_cancel_all_tasks(loop)
loop.run_until_complete(loop.shutdown_asyncgens())
loop.run_until_complete(loop.shutdown_default_executor())
finally:
events.set_event_loop(None)
loop.close()
def _cancel_all_tasks(loop):
to_cancel = tasks.all_tasks(loop)
if not to_cancel:
return
for task in to_cancel:
task.cancel()
loop.run_until_complete(
tasks.gather(*to_cancel, loop=loop, return_exceptions=True))
for task in to_cancel:
if task.cancelled():
continue
if task.exception() is not None:
loop.call_exception_handler({
'message': 'unhandled exception during asyncio.run() shutdown',
'exception': task.exception(),
'task': task,
})

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import collections
import warnings
try:
import ssl
except ImportError: # pragma: no cover
ssl = None
from . import constants
from . import protocols
from . import transports
from .log import logger
def _create_transport_context(server_side, server_hostname):
if server_side:
raise ValueError('Server side SSL needs a valid SSLContext')
# Client side may pass ssl=True to use a default
# context; in that case the sslcontext passed is None.
# The default is secure for client connections.
# Python 3.4+: use up-to-date strong settings.
sslcontext = ssl.create_default_context()
if not server_hostname:
sslcontext.check_hostname = False
return sslcontext
# States of an _SSLPipe.
_UNWRAPPED = "UNWRAPPED"
_DO_HANDSHAKE = "DO_HANDSHAKE"
_WRAPPED = "WRAPPED"
_SHUTDOWN = "SHUTDOWN"
class _SSLPipe(object):
"""An SSL "Pipe".
An SSL pipe allows you to communicate with an SSL/TLS protocol instance
through memory buffers. It can be used to implement a security layer for an
existing connection where you don't have access to the connection's file
descriptor, or for some reason you don't want to use it.
An SSL pipe can be in "wrapped" and "unwrapped" mode. In unwrapped mode,
data is passed through untransformed. In wrapped mode, application level
data is encrypted to SSL record level data and vice versa. The SSL record
level is the lowest level in the SSL protocol suite and is what travels
as-is over the wire.
An SslPipe initially is in "unwrapped" mode. To start SSL, call
do_handshake(). To shutdown SSL again, call unwrap().
"""
max_size = 256 * 1024 # Buffer size passed to read()
def __init__(self, context, server_side, server_hostname=None):
"""
The *context* argument specifies the ssl.SSLContext to use.
The *server_side* argument indicates whether this is a server side or
client side transport.
The optional *server_hostname* argument can be used to specify the
hostname you are connecting to. You may only specify this parameter if
the _ssl module supports Server Name Indication (SNI).
"""
self._context = context
self._server_side = server_side
self._server_hostname = server_hostname
self._state = _UNWRAPPED
self._incoming = ssl.MemoryBIO()
self._outgoing = ssl.MemoryBIO()
self._sslobj = None
self._need_ssldata = False
self._handshake_cb = None
self._shutdown_cb = None
@property
def context(self):
"""The SSL context passed to the constructor."""
return self._context
@property
def ssl_object(self):
"""The internal ssl.SSLObject instance.
Return None if the pipe is not wrapped.
"""
return self._sslobj
@property
def need_ssldata(self):
"""Whether more record level data is needed to complete a handshake
that is currently in progress."""
return self._need_ssldata
@property
def wrapped(self):
"""
Whether a security layer is currently in effect.
Return False during handshake.
"""
return self._state == _WRAPPED
def do_handshake(self, callback=None):
"""Start the SSL handshake.
Return a list of ssldata. A ssldata element is a list of buffers
The optional *callback* argument can be used to install a callback that
will be called when the handshake is complete. The callback will be
called with None if successful, else an exception instance.
"""
if self._state != _UNWRAPPED:
raise RuntimeError('handshake in progress or completed')
self._sslobj = self._context.wrap_bio(
self._incoming, self._outgoing,
server_side=self._server_side,
server_hostname=self._server_hostname)
self._state = _DO_HANDSHAKE
self._handshake_cb = callback
ssldata, appdata = self.feed_ssldata(b'', only_handshake=True)
assert len(appdata) == 0
return ssldata
def shutdown(self, callback=None):
"""Start the SSL shutdown sequence.
Return a list of ssldata. A ssldata element is a list of buffers
The optional *callback* argument can be used to install a callback that
will be called when the shutdown is complete. The callback will be
called without arguments.
"""
if self._state == _UNWRAPPED:
raise RuntimeError('no security layer present')
if self._state == _SHUTDOWN:
raise RuntimeError('shutdown in progress')
assert self._state in (_WRAPPED, _DO_HANDSHAKE)
self._state = _SHUTDOWN
self._shutdown_cb = callback
ssldata, appdata = self.feed_ssldata(b'')
assert appdata == [] or appdata == [b'']
return ssldata
def feed_eof(self):
"""Send a potentially "ragged" EOF.
This method will raise an SSL_ERROR_EOF exception if the EOF is
unexpected.
"""
self._incoming.write_eof()
ssldata, appdata = self.feed_ssldata(b'')
assert appdata == [] or appdata == [b'']
def feed_ssldata(self, data, only_handshake=False):
"""Feed SSL record level data into the pipe.
The data must be a bytes instance. It is OK to send an empty bytes
instance. This can be used to get ssldata for a handshake initiated by
this endpoint.
Return a (ssldata, appdata) tuple. The ssldata element is a list of
buffers containing SSL data that needs to be sent to the remote SSL.
The appdata element is a list of buffers containing plaintext data that
needs to be forwarded to the application. The appdata list may contain
an empty buffer indicating an SSL "close_notify" alert. This alert must
be acknowledged by calling shutdown().
"""
if self._state == _UNWRAPPED:
# If unwrapped, pass plaintext data straight through.
if data:
appdata = [data]
else:
appdata = []
return ([], appdata)
self._need_ssldata = False
if data:
self._incoming.write(data)
ssldata = []
appdata = []
try:
if self._state == _DO_HANDSHAKE:
# Call do_handshake() until it doesn't raise anymore.
self._sslobj.do_handshake()
self._state = _WRAPPED
if self._handshake_cb:
self._handshake_cb(None)
if only_handshake:
return (ssldata, appdata)
# Handshake done: execute the wrapped block
if self._state == _WRAPPED:
# Main state: read data from SSL until close_notify
while True:
chunk = self._sslobj.read(self.max_size)
appdata.append(chunk)
if not chunk: # close_notify
break
elif self._state == _SHUTDOWN:
# Call shutdown() until it doesn't raise anymore.
self._sslobj.unwrap()
self._sslobj = None
self._state = _UNWRAPPED
if self._shutdown_cb:
self._shutdown_cb()
elif self._state == _UNWRAPPED:
# Drain possible plaintext data after close_notify.
appdata.append(self._incoming.read())
except (ssl.SSLError, ssl.CertificateError) as exc:
exc_errno = getattr(exc, 'errno', None)
if exc_errno not in (
ssl.SSL_ERROR_WANT_READ, ssl.SSL_ERROR_WANT_WRITE,
ssl.SSL_ERROR_SYSCALL):
if self._state == _DO_HANDSHAKE and self._handshake_cb:
self._handshake_cb(exc)
raise
self._need_ssldata = (exc_errno == ssl.SSL_ERROR_WANT_READ)
# Check for record level data that needs to be sent back.
# Happens for the initial handshake and renegotiations.
if self._outgoing.pending:
ssldata.append(self._outgoing.read())
return (ssldata, appdata)
def feed_appdata(self, data, offset=0):
"""Feed plaintext data into the pipe.
Return an (ssldata, offset) tuple. The ssldata element is a list of
buffers containing record level data that needs to be sent to the
remote SSL instance. The offset is the number of plaintext bytes that
were processed, which may be less than the length of data.
NOTE: In case of short writes, this call MUST be retried with the SAME
buffer passed into the *data* argument (i.e. the id() must be the
same). This is an OpenSSL requirement. A further particularity is that
a short write will always have offset == 0, because the _ssl module
does not enable partial writes. And even though the offset is zero,
there will still be encrypted data in ssldata.
"""
assert 0 <= offset <= len(data)
if self._state == _UNWRAPPED:
# pass through data in unwrapped mode
if offset < len(data):
ssldata = [data[offset:]]
else:
ssldata = []
return (ssldata, len(data))
ssldata = []
view = memoryview(data)
while True:
self._need_ssldata = False
try:
if offset < len(view):
offset += self._sslobj.write(view[offset:])
except ssl.SSLError as exc:
# It is not allowed to call write() after unwrap() until the
# close_notify is acknowledged. We return the condition to the
# caller as a short write.
exc_errno = getattr(exc, 'errno', None)
if exc.reason == 'PROTOCOL_IS_SHUTDOWN':
exc_errno = exc.errno = ssl.SSL_ERROR_WANT_READ
if exc_errno not in (ssl.SSL_ERROR_WANT_READ,
ssl.SSL_ERROR_WANT_WRITE,
ssl.SSL_ERROR_SYSCALL):
raise
self._need_ssldata = (exc_errno == ssl.SSL_ERROR_WANT_READ)
# See if there's any record level data back for us.
if self._outgoing.pending:
ssldata.append(self._outgoing.read())
if offset == len(view) or self._need_ssldata:
break
return (ssldata, offset)
class _SSLProtocolTransport(transports._FlowControlMixin,
transports.Transport):
_sendfile_compatible = constants._SendfileMode.FALLBACK
def __init__(self, loop, ssl_protocol):
self._loop = loop
# SSLProtocol instance
self._ssl_protocol = ssl_protocol
self._closed = False
def get_extra_info(self, name, default=None):
"""Get optional transport information."""
return self._ssl_protocol._get_extra_info(name, default)
def set_protocol(self, protocol):
self._ssl_protocol._set_app_protocol(protocol)
def get_protocol(self):
return self._ssl_protocol._app_protocol
def is_closing(self):
return self._closed
def close(self):
"""Close the transport.
Buffered data will be flushed asynchronously. No more data
will be received. After all buffered data is flushed, the
protocol's connection_lost() method will (eventually) called
with None as its argument.
"""
self._closed = True
self._ssl_protocol._start_shutdown()
def __del__(self, _warn=warnings.warn):
if not self._closed:
_warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
self.close()
def is_reading(self):
tr = self._ssl_protocol._transport
if tr is None:
raise RuntimeError('SSL transport has not been initialized yet')
return tr.is_reading()
def pause_reading(self):
"""Pause the receiving end.
No data will be passed to the protocol's data_received()
method until resume_reading() is called.
"""
self._ssl_protocol._transport.pause_reading()
def resume_reading(self):
"""Resume the receiving end.
Data received will once again be passed to the protocol's
data_received() method.
"""
self._ssl_protocol._transport.resume_reading()
def set_write_buffer_limits(self, high=None, low=None):
"""Set the high- and low-water limits for write flow control.
These two values control when to call the protocol's
pause_writing() and resume_writing() methods. If specified,
the low-water limit must be less than or equal to the
high-water limit. Neither value can be negative.
The defaults are implementation-specific. If only the
high-water limit is given, the low-water limit defaults to an
implementation-specific value less than or equal to the
high-water limit. Setting high to zero forces low to zero as
well, and causes pause_writing() to be called whenever the
buffer becomes non-empty. Setting low to zero causes
resume_writing() to be called only once the buffer is empty.
Use of zero for either limit is generally sub-optimal as it
reduces opportunities for doing I/O and computation
concurrently.
"""
self._ssl_protocol._transport.set_write_buffer_limits(high, low)
def get_write_buffer_size(self):
"""Return the current size of the write buffer."""
return self._ssl_protocol._transport.get_write_buffer_size()
@property
def _protocol_paused(self):
# Required for sendfile fallback pause_writing/resume_writing logic
return self._ssl_protocol._transport._protocol_paused
def write(self, data):
"""Write some data bytes to the transport.
This does not block; it buffers the data and arranges for it
to be sent out asynchronously.
"""
if not isinstance(data, (bytes, bytearray, memoryview)):
raise TypeError(f"data: expecting a bytes-like instance, "
f"got {type(data).__name__}")
if not data:
return
self._ssl_protocol._write_appdata(data)
def can_write_eof(self):
"""Return True if this transport supports write_eof(), False if not."""
return False
def abort(self):
"""Close the transport immediately.
Buffered data will be lost. No more data will be received.
The protocol's connection_lost() method will (eventually) be
called with None as its argument.
"""
self._ssl_protocol._abort()
self._closed = True
class SSLProtocol(protocols.Protocol):
"""SSL protocol.
Implementation of SSL on top of a socket using incoming and outgoing
buffers which are ssl.MemoryBIO objects.
"""
def __init__(self, loop, app_protocol, sslcontext, waiter,
server_side=False, server_hostname=None,
call_connection_made=True,
ssl_handshake_timeout=None):
if ssl is None:
raise RuntimeError('stdlib ssl module not available')
if ssl_handshake_timeout is None:
ssl_handshake_timeout = constants.SSL_HANDSHAKE_TIMEOUT
elif ssl_handshake_timeout <= 0:
raise ValueError(
f"ssl_handshake_timeout should be a positive number, "
f"got {ssl_handshake_timeout}")
if not sslcontext:
sslcontext = _create_transport_context(
server_side, server_hostname)
self._server_side = server_side
if server_hostname and not server_side:
self._server_hostname = server_hostname
else:
self._server_hostname = None
self._sslcontext = sslcontext
# SSL-specific extra info. More info are set when the handshake
# completes.
self._extra = dict(sslcontext=sslcontext)
# App data write buffering
self._write_backlog = collections.deque()
self._write_buffer_size = 0
self._waiter = waiter
self._loop = loop
self._set_app_protocol(app_protocol)
self._app_transport = _SSLProtocolTransport(self._loop, self)
# _SSLPipe instance (None until the connection is made)
self._sslpipe = None
self._session_established = False
self._in_handshake = False
self._in_shutdown = False
# transport, ex: SelectorSocketTransport
self._transport = None
self._call_connection_made = call_connection_made
self._ssl_handshake_timeout = ssl_handshake_timeout
def _set_app_protocol(self, app_protocol):
self._app_protocol = app_protocol
self._app_protocol_is_buffer = \
isinstance(app_protocol, protocols.BufferedProtocol)
def _wakeup_waiter(self, exc=None):
if self._waiter is None:
return
if not self._waiter.cancelled():
if exc is not None:
self._waiter.set_exception(exc)
else:
self._waiter.set_result(None)
self._waiter = None
def connection_made(self, transport):
"""Called when the low-level connection is made.
Start the SSL handshake.
"""
self._transport = transport
self._sslpipe = _SSLPipe(self._sslcontext,
self._server_side,
self._server_hostname)
self._start_handshake()
def connection_lost(self, exc):
"""Called when the low-level connection is lost or closed.
The argument is an exception object or None (the latter
meaning a regular EOF is received or the connection was
aborted or closed).
"""
if self._session_established:
self._session_established = False
self._loop.call_soon(self._app_protocol.connection_lost, exc)
else:
# Most likely an exception occurred while in SSL handshake.
# Just mark the app transport as closed so that its __del__
# doesn't complain.
if self._app_transport is not None:
self._app_transport._closed = True
self._transport = None
self._app_transport = None
if getattr(self, '_handshake_timeout_handle', None):
self._handshake_timeout_handle.cancel()
self._wakeup_waiter(exc)
self._app_protocol = None
self._sslpipe = None
def pause_writing(self):
"""Called when the low-level transport's buffer goes over
the high-water mark.
"""
self._app_protocol.pause_writing()
def resume_writing(self):
"""Called when the low-level transport's buffer drains below
the low-water mark.
"""
self._app_protocol.resume_writing()
def data_received(self, data):
"""Called when some SSL data is received.
The argument is a bytes object.
"""
if self._sslpipe is None:
# transport closing, sslpipe is destroyed
return
try:
ssldata, appdata = self._sslpipe.feed_ssldata(data)
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as e:
self._fatal_error(e, 'SSL error in data received')
return
for chunk in ssldata:
self._transport.write(chunk)
for chunk in appdata:
if chunk:
try:
if self._app_protocol_is_buffer:
protocols._feed_data_to_buffered_proto(
self._app_protocol, chunk)
else:
self._app_protocol.data_received(chunk)
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as ex:
self._fatal_error(
ex, 'application protocol failed to receive SSL data')
return
else:
self._start_shutdown()
break
def eof_received(self):
"""Called when the other end of the low-level stream
is half-closed.
If this returns a false value (including None), the transport
will close itself. If it returns a true value, closing the
transport is up to the protocol.
"""
try:
if self._loop.get_debug():
logger.debug("%r received EOF", self)
self._wakeup_waiter(ConnectionResetError)
if not self._in_handshake:
keep_open = self._app_protocol.eof_received()
if keep_open:
logger.warning('returning true from eof_received() '
'has no effect when using ssl')
finally:
self._transport.close()
def _get_extra_info(self, name, default=None):
if name in self._extra:
return self._extra[name]
elif self._transport is not None:
return self._transport.get_extra_info(name, default)
else:
return default
def _start_shutdown(self):
if self._in_shutdown:
return
if self._in_handshake:
self._abort()
else:
self._in_shutdown = True
self._write_appdata(b'')
def _write_appdata(self, data):
self._write_backlog.append((data, 0))
self._write_buffer_size += len(data)
self._process_write_backlog()
def _start_handshake(self):
if self._loop.get_debug():
logger.debug("%r starts SSL handshake", self)
self._handshake_start_time = self._loop.time()
else:
self._handshake_start_time = None
self._in_handshake = True
# (b'', 1) is a special value in _process_write_backlog() to do
# the SSL handshake
self._write_backlog.append((b'', 1))
self._handshake_timeout_handle = \
self._loop.call_later(self._ssl_handshake_timeout,
self._check_handshake_timeout)
self._process_write_backlog()
def _check_handshake_timeout(self):
if self._in_handshake is True:
msg = (
f"SSL handshake is taking longer than "
f"{self._ssl_handshake_timeout} seconds: "
f"aborting the connection"
)
self._fatal_error(ConnectionAbortedError(msg))
def _on_handshake_complete(self, handshake_exc):
self._in_handshake = False
self._handshake_timeout_handle.cancel()
sslobj = self._sslpipe.ssl_object
try:
if handshake_exc is not None:
raise handshake_exc
peercert = sslobj.getpeercert()
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
if isinstance(exc, ssl.CertificateError):
msg = 'SSL handshake failed on verifying the certificate'
else:
msg = 'SSL handshake failed'
self._fatal_error(exc, msg)
return
if self._loop.get_debug():
dt = self._loop.time() - self._handshake_start_time
logger.debug("%r: SSL handshake took %.1f ms", self, dt * 1e3)
# Add extra info that becomes available after handshake.
self._extra.update(peercert=peercert,
cipher=sslobj.cipher(),
compression=sslobj.compression(),
ssl_object=sslobj,
)
if self._call_connection_made:
self._app_protocol.connection_made(self._app_transport)
self._wakeup_waiter()
self._session_established = True
# In case transport.write() was already called. Don't call
# immediately _process_write_backlog(), but schedule it:
# _on_handshake_complete() can be called indirectly from
# _process_write_backlog(), and _process_write_backlog() is not
# reentrant.
self._loop.call_soon(self._process_write_backlog)
def _process_write_backlog(self):
# Try to make progress on the write backlog.
if self._transport is None or self._sslpipe is None:
return
try:
for i in range(len(self._write_backlog)):
data, offset = self._write_backlog[0]
if data:
ssldata, offset = self._sslpipe.feed_appdata(data, offset)
elif offset:
ssldata = self._sslpipe.do_handshake(
self._on_handshake_complete)
offset = 1
else:
ssldata = self._sslpipe.shutdown(self._finalize)
offset = 1
for chunk in ssldata:
self._transport.write(chunk)
if offset < len(data):
self._write_backlog[0] = (data, offset)
# A short write means that a write is blocked on a read
# We need to enable reading if it is paused!
assert self._sslpipe.need_ssldata
if self._transport._paused:
self._transport.resume_reading()
break
# An entire chunk from the backlog was processed. We can
# delete it and reduce the outstanding buffer size.
del self._write_backlog[0]
self._write_buffer_size -= len(data)
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
if self._in_handshake:
# Exceptions will be re-raised in _on_handshake_complete.
self._on_handshake_complete(exc)
else:
self._fatal_error(exc, 'Fatal error on SSL transport')
def _fatal_error(self, exc, message='Fatal error on transport'):
if isinstance(exc, OSError):
if self._loop.get_debug():
logger.debug("%r: %s", self, message, exc_info=True)
else:
self._loop.call_exception_handler({
'message': message,
'exception': exc,
'transport': self._transport,
'protocol': self,
})
if self._transport:
self._transport._force_close(exc)
def _finalize(self):
self._sslpipe = None
if self._transport is not None:
self._transport.close()
def _abort(self):
try:
if self._transport is not None:
self._transport.abort()
finally:
self._finalize()

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@ -0,0 +1,149 @@
"""Support for running coroutines in parallel with staggered start times."""
__all__ = 'staggered_race',
import contextlib
import typing
from . import events
from . import exceptions as exceptions_mod
from . import locks
from . import tasks
async def staggered_race(
coro_fns: typing.Iterable[typing.Callable[[], typing.Awaitable]],
delay: typing.Optional[float],
*,
loop: events.AbstractEventLoop = None,
) -> typing.Tuple[
typing.Any,
typing.Optional[int],
typing.List[typing.Optional[Exception]]
]:
"""Run coroutines with staggered start times and take the first to finish.
This method takes an iterable of coroutine functions. The first one is
started immediately. From then on, whenever the immediately preceding one
fails (raises an exception), or when *delay* seconds has passed, the next
coroutine is started. This continues until one of the coroutines complete
successfully, in which case all others are cancelled, or until all
coroutines fail.
The coroutines provided should be well-behaved in the following way:
* They should only ``return`` if completed successfully.
* They should always raise an exception if they did not complete
successfully. In particular, if they handle cancellation, they should
probably reraise, like this::
try:
# do work
except asyncio.CancelledError:
# undo partially completed work
raise
Args:
coro_fns: an iterable of coroutine functions, i.e. callables that
return a coroutine object when called. Use ``functools.partial`` or
lambdas to pass arguments.
delay: amount of time, in seconds, between starting coroutines. If
``None``, the coroutines will run sequentially.
loop: the event loop to use.
Returns:
tuple *(winner_result, winner_index, exceptions)* where
- *winner_result*: the result of the winning coroutine, or ``None``
if no coroutines won.
- *winner_index*: the index of the winning coroutine in
``coro_fns``, or ``None`` if no coroutines won. If the winning
coroutine may return None on success, *winner_index* can be used
to definitively determine whether any coroutine won.
- *exceptions*: list of exceptions returned by the coroutines.
``len(exceptions)`` is equal to the number of coroutines actually
started, and the order is the same as in ``coro_fns``. The winning
coroutine's entry is ``None``.
"""
# TODO: when we have aiter() and anext(), allow async iterables in coro_fns.
loop = loop or events.get_running_loop()
enum_coro_fns = enumerate(coro_fns)
winner_result = None
winner_index = None
exceptions = []
running_tasks = []
async def run_one_coro(
previous_failed: typing.Optional[locks.Event]) -> None:
# Wait for the previous task to finish, or for delay seconds
if previous_failed is not None:
with contextlib.suppress(exceptions_mod.TimeoutError):
# Use asyncio.wait_for() instead of asyncio.wait() here, so
# that if we get cancelled at this point, Event.wait() is also
# cancelled, otherwise there will be a "Task destroyed but it is
# pending" later.
await tasks.wait_for(previous_failed.wait(), delay)
# Get the next coroutine to run
try:
this_index, coro_fn = next(enum_coro_fns)
except StopIteration:
return
# Start task that will run the next coroutine
this_failed = locks.Event()
next_task = loop.create_task(run_one_coro(this_failed))
running_tasks.append(next_task)
assert len(running_tasks) == this_index + 2
# Prepare place to put this coroutine's exceptions if not won
exceptions.append(None)
assert len(exceptions) == this_index + 1
try:
result = await coro_fn()
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as e:
exceptions[this_index] = e
this_failed.set() # Kickstart the next coroutine
else:
# Store winner's results
nonlocal winner_index, winner_result
assert winner_index is None
winner_index = this_index
winner_result = result
# Cancel all other tasks. We take care to not cancel the current
# task as well. If we do so, then since there is no `await` after
# here and CancelledError are usually thrown at one, we will
# encounter a curious corner case where the current task will end
# up as done() == True, cancelled() == False, exception() ==
# asyncio.CancelledError. This behavior is specified in
# https://bugs.python.org/issue30048
for i, t in enumerate(running_tasks):
if i != this_index:
t.cancel()
first_task = loop.create_task(run_one_coro(None))
running_tasks.append(first_task)
try:
# Wait for a growing list of tasks to all finish: poor man's version of
# curio's TaskGroup or trio's nursery
done_count = 0
while done_count != len(running_tasks):
done, _ = await tasks.wait(running_tasks)
done_count = len(done)
# If run_one_coro raises an unhandled exception, it's probably a
# programming error, and I want to see it.
if __debug__:
for d in done:
if d.done() and not d.cancelled() and d.exception():
raise d.exception()
return winner_result, winner_index, exceptions
finally:
# Make sure no tasks are left running if we leave this function
for t in running_tasks:
t.cancel()

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@ -0,0 +1,741 @@
__all__ = (
'StreamReader', 'StreamWriter', 'StreamReaderProtocol',
'open_connection', 'start_server')
import socket
import sys
import warnings
import weakref
if hasattr(socket, 'AF_UNIX'):
__all__ += ('open_unix_connection', 'start_unix_server')
from . import coroutines
from . import events
from . import exceptions
from . import format_helpers
from . import protocols
from .log import logger
from .tasks import sleep
_DEFAULT_LIMIT = 2 ** 16 # 64 KiB
async def open_connection(host=None, port=None, *,
loop=None, limit=_DEFAULT_LIMIT, **kwds):
"""A wrapper for create_connection() returning a (reader, writer) pair.
The reader returned is a StreamReader instance; the writer is a
StreamWriter instance.
The arguments are all the usual arguments to create_connection()
except protocol_factory; most common are positional host and port,
with various optional keyword arguments following.
Additional optional keyword arguments are loop (to set the event loop
instance to use) and limit (to set the buffer limit passed to the
StreamReader).
(If you want to customize the StreamReader and/or
StreamReaderProtocol classes, just copy the code -- there's
really nothing special here except some convenience.)
"""
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
reader = StreamReader(limit=limit, loop=loop)
protocol = StreamReaderProtocol(reader, loop=loop)
transport, _ = await loop.create_connection(
lambda: protocol, host, port, **kwds)
writer = StreamWriter(transport, protocol, reader, loop)
return reader, writer
async def start_server(client_connected_cb, host=None, port=None, *,
loop=None, limit=_DEFAULT_LIMIT, **kwds):
"""Start a socket server, call back for each client connected.
The first parameter, `client_connected_cb`, takes two parameters:
client_reader, client_writer. client_reader is a StreamReader
object, while client_writer is a StreamWriter object. This
parameter can either be a plain callback function or a coroutine;
if it is a coroutine, it will be automatically converted into a
Task.
The rest of the arguments are all the usual arguments to
loop.create_server() except protocol_factory; most common are
positional host and port, with various optional keyword arguments
following. The return value is the same as loop.create_server().
Additional optional keyword arguments are loop (to set the event loop
instance to use) and limit (to set the buffer limit passed to the
StreamReader).
The return value is the same as loop.create_server(), i.e. a
Server object which can be used to stop the service.
"""
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
def factory():
reader = StreamReader(limit=limit, loop=loop)
protocol = StreamReaderProtocol(reader, client_connected_cb,
loop=loop)
return protocol
return await loop.create_server(factory, host, port, **kwds)
if hasattr(socket, 'AF_UNIX'):
# UNIX Domain Sockets are supported on this platform
async def open_unix_connection(path=None, *,
loop=None, limit=_DEFAULT_LIMIT, **kwds):
"""Similar to `open_connection` but works with UNIX Domain Sockets."""
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
reader = StreamReader(limit=limit, loop=loop)
protocol = StreamReaderProtocol(reader, loop=loop)
transport, _ = await loop.create_unix_connection(
lambda: protocol, path, **kwds)
writer = StreamWriter(transport, protocol, reader, loop)
return reader, writer
async def start_unix_server(client_connected_cb, path=None, *,
loop=None, limit=_DEFAULT_LIMIT, **kwds):
"""Similar to `start_server` but works with UNIX Domain Sockets."""
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
def factory():
reader = StreamReader(limit=limit, loop=loop)
protocol = StreamReaderProtocol(reader, client_connected_cb,
loop=loop)
return protocol
return await loop.create_unix_server(factory, path, **kwds)
class FlowControlMixin(protocols.Protocol):
"""Reusable flow control logic for StreamWriter.drain().
This implements the protocol methods pause_writing(),
resume_writing() and connection_lost(). If the subclass overrides
these it must call the super methods.
StreamWriter.drain() must wait for _drain_helper() coroutine.
"""
def __init__(self, loop=None):
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
self._paused = False
self._drain_waiter = None
self._connection_lost = False
def pause_writing(self):
assert not self._paused
self._paused = True
if self._loop.get_debug():
logger.debug("%r pauses writing", self)
def resume_writing(self):
assert self._paused
self._paused = False
if self._loop.get_debug():
logger.debug("%r resumes writing", self)
waiter = self._drain_waiter
if waiter is not None:
self._drain_waiter = None
if not waiter.done():
waiter.set_result(None)
def connection_lost(self, exc):
self._connection_lost = True
# Wake up the writer if currently paused.
if not self._paused:
return
waiter = self._drain_waiter
if waiter is None:
return
self._drain_waiter = None
if waiter.done():
return
if exc is None:
waiter.set_result(None)
else:
waiter.set_exception(exc)
async def _drain_helper(self):
if self._connection_lost:
raise ConnectionResetError('Connection lost')
if not self._paused:
return
waiter = self._drain_waiter
assert waiter is None or waiter.cancelled()
waiter = self._loop.create_future()
self._drain_waiter = waiter
await waiter
def _get_close_waiter(self, stream):
raise NotImplementedError
class StreamReaderProtocol(FlowControlMixin, protocols.Protocol):
"""Helper class to adapt between Protocol and StreamReader.
(This is a helper class instead of making StreamReader itself a
Protocol subclass, because the StreamReader has other potential
uses, and to prevent the user of the StreamReader to accidentally
call inappropriate methods of the protocol.)
"""
_source_traceback = None
def __init__(self, stream_reader, client_connected_cb=None, loop=None):
super().__init__(loop=loop)
if stream_reader is not None:
self._stream_reader_wr = weakref.ref(stream_reader)
self._source_traceback = stream_reader._source_traceback
else:
self._stream_reader_wr = None
if client_connected_cb is not None:
# This is a stream created by the `create_server()` function.
# Keep a strong reference to the reader until a connection
# is established.
self._strong_reader = stream_reader
self._reject_connection = False
self._stream_writer = None
self._transport = None
self._client_connected_cb = client_connected_cb
self._over_ssl = False
self._closed = self._loop.create_future()
@property
def _stream_reader(self):
if self._stream_reader_wr is None:
return None
return self._stream_reader_wr()
def connection_made(self, transport):
if self._reject_connection:
context = {
'message': ('An open stream was garbage collected prior to '
'establishing network connection; '
'call "stream.close()" explicitly.')
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
transport.abort()
return
self._transport = transport
reader = self._stream_reader
if reader is not None:
reader.set_transport(transport)
self._over_ssl = transport.get_extra_info('sslcontext') is not None
if self._client_connected_cb is not None:
self._stream_writer = StreamWriter(transport, self,
reader,
self._loop)
res = self._client_connected_cb(reader,
self._stream_writer)
if coroutines.iscoroutine(res):
self._loop.create_task(res)
self._strong_reader = None
def connection_lost(self, exc):
reader = self._stream_reader
if reader is not None:
if exc is None:
reader.feed_eof()
else:
reader.set_exception(exc)
if not self._closed.done():
if exc is None:
self._closed.set_result(None)
else:
self._closed.set_exception(exc)
super().connection_lost(exc)
self._stream_reader_wr = None
self._stream_writer = None
self._transport = None
def data_received(self, data):
reader = self._stream_reader
if reader is not None:
reader.feed_data(data)
def eof_received(self):
reader = self._stream_reader
if reader is not None:
reader.feed_eof()
if self._over_ssl:
# Prevent a warning in SSLProtocol.eof_received:
# "returning true from eof_received()
# has no effect when using ssl"
return False
return True
def _get_close_waiter(self, stream):
return self._closed
def __del__(self):
# Prevent reports about unhandled exceptions.
# Better than self._closed._log_traceback = False hack
closed = self._closed
if closed.done() and not closed.cancelled():
closed.exception()
class StreamWriter:
"""Wraps a Transport.
This exposes write(), writelines(), [can_]write_eof(),
get_extra_info() and close(). It adds drain() which returns an
optional Future on which you can wait for flow control. It also
adds a transport property which references the Transport
directly.
"""
def __init__(self, transport, protocol, reader, loop):
self._transport = transport
self._protocol = protocol
# drain() expects that the reader has an exception() method
assert reader is None or isinstance(reader, StreamReader)
self._reader = reader
self._loop = loop
self._complete_fut = self._loop.create_future()
self._complete_fut.set_result(None)
def __repr__(self):
info = [self.__class__.__name__, f'transport={self._transport!r}']
if self._reader is not None:
info.append(f'reader={self._reader!r}')
return '<{}>'.format(' '.join(info))
@property
def transport(self):
return self._transport
def write(self, data):
self._transport.write(data)
def writelines(self, data):
self._transport.writelines(data)
def write_eof(self):
return self._transport.write_eof()
def can_write_eof(self):
return self._transport.can_write_eof()
def close(self):
return self._transport.close()
def is_closing(self):
return self._transport.is_closing()
async def wait_closed(self):
await self._protocol._get_close_waiter(self)
def get_extra_info(self, name, default=None):
return self._transport.get_extra_info(name, default)
async def drain(self):
"""Flush the write buffer.
The intended use is to write
w.write(data)
await w.drain()
"""
if self._reader is not None:
exc = self._reader.exception()
if exc is not None:
raise exc
if self._transport.is_closing():
# Wait for protocol.connection_lost() call
# Raise connection closing error if any,
# ConnectionResetError otherwise
# Yield to the event loop so connection_lost() may be
# called. Without this, _drain_helper() would return
# immediately, and code that calls
# write(...); await drain()
# in a loop would never call connection_lost(), so it
# would not see an error when the socket is closed.
await sleep(0)
await self._protocol._drain_helper()
class StreamReader:
_source_traceback = None
def __init__(self, limit=_DEFAULT_LIMIT, loop=None):
# The line length limit is a security feature;
# it also doubles as half the buffer limit.
if limit <= 0:
raise ValueError('Limit cannot be <= 0')
self._limit = limit
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
self._buffer = bytearray()
self._eof = False # Whether we're done.
self._waiter = None # A future used by _wait_for_data()
self._exception = None
self._transport = None
self._paused = False
if self._loop.get_debug():
self._source_traceback = format_helpers.extract_stack(
sys._getframe(1))
def __repr__(self):
info = ['StreamReader']
if self._buffer:
info.append(f'{len(self._buffer)} bytes')
if self._eof:
info.append('eof')
if self._limit != _DEFAULT_LIMIT:
info.append(f'limit={self._limit}')
if self._waiter:
info.append(f'waiter={self._waiter!r}')
if self._exception:
info.append(f'exception={self._exception!r}')
if self._transport:
info.append(f'transport={self._transport!r}')
if self._paused:
info.append('paused')
return '<{}>'.format(' '.join(info))
def exception(self):
return self._exception
def set_exception(self, exc):
self._exception = exc
waiter = self._waiter
if waiter is not None:
self._waiter = None
if not waiter.cancelled():
waiter.set_exception(exc)
def _wakeup_waiter(self):
"""Wakeup read*() functions waiting for data or EOF."""
waiter = self._waiter
if waiter is not None:
self._waiter = None
if not waiter.cancelled():
waiter.set_result(None)
def set_transport(self, transport):
assert self._transport is None, 'Transport already set'
self._transport = transport
def _maybe_resume_transport(self):
if self._paused and len(self._buffer) <= self._limit:
self._paused = False
self._transport.resume_reading()
def feed_eof(self):
self._eof = True
self._wakeup_waiter()
def at_eof(self):
"""Return True if the buffer is empty and 'feed_eof' was called."""
return self._eof and not self._buffer
def feed_data(self, data):
assert not self._eof, 'feed_data after feed_eof'
if not data:
return
self._buffer.extend(data)
self._wakeup_waiter()
if (self._transport is not None and
not self._paused and
len(self._buffer) > 2 * self._limit):
try:
self._transport.pause_reading()
except NotImplementedError:
# The transport can't be paused.
# We'll just have to buffer all data.
# Forget the transport so we don't keep trying.
self._transport = None
else:
self._paused = True
async def _wait_for_data(self, func_name):
"""Wait until feed_data() or feed_eof() is called.
If stream was paused, automatically resume it.
"""
# StreamReader uses a future to link the protocol feed_data() method
# to a read coroutine. Running two read coroutines at the same time
# would have an unexpected behaviour. It would not possible to know
# which coroutine would get the next data.
if self._waiter is not None:
raise RuntimeError(
f'{func_name}() called while another coroutine is '
f'already waiting for incoming data')
assert not self._eof, '_wait_for_data after EOF'
# Waiting for data while paused will make deadlock, so prevent it.
# This is essential for readexactly(n) for case when n > self._limit.
if self._paused:
self._paused = False
self._transport.resume_reading()
self._waiter = self._loop.create_future()
try:
await self._waiter
finally:
self._waiter = None
async def readline(self):
"""Read chunk of data from the stream until newline (b'\n') is found.
On success, return chunk that ends with newline. If only partial
line can be read due to EOF, return incomplete line without
terminating newline. When EOF was reached while no bytes read, empty
bytes object is returned.
If limit is reached, ValueError will be raised. In that case, if
newline was found, complete line including newline will be removed
from internal buffer. Else, internal buffer will be cleared. Limit is
compared against part of the line without newline.
If stream was paused, this function will automatically resume it if
needed.
"""
sep = b'\n'
seplen = len(sep)
try:
line = await self.readuntil(sep)
except exceptions.IncompleteReadError as e:
return e.partial
except exceptions.LimitOverrunError as e:
if self._buffer.startswith(sep, e.consumed):
del self._buffer[:e.consumed + seplen]
else:
self._buffer.clear()
self._maybe_resume_transport()
raise ValueError(e.args[0])
return line
async def readuntil(self, separator=b'\n'):
"""Read data from the stream until ``separator`` is found.
On success, the data and separator will be removed from the
internal buffer (consumed). Returned data will include the
separator at the end.
Configured stream limit is used to check result. Limit sets the
maximal length of data that can be returned, not counting the
separator.
If an EOF occurs and the complete separator is still not found,
an IncompleteReadError exception will be raised, and the internal
buffer will be reset. The IncompleteReadError.partial attribute
may contain the separator partially.
If the data cannot be read because of over limit, a
LimitOverrunError exception will be raised, and the data
will be left in the internal buffer, so it can be read again.
"""
seplen = len(separator)
if seplen == 0:
raise ValueError('Separator should be at least one-byte string')
if self._exception is not None:
raise self._exception
# Consume whole buffer except last bytes, which length is
# one less than seplen. Let's check corner cases with
# separator='SEPARATOR':
# * we have received almost complete separator (without last
# byte). i.e buffer='some textSEPARATO'. In this case we
# can safely consume len(separator) - 1 bytes.
# * last byte of buffer is first byte of separator, i.e.
# buffer='abcdefghijklmnopqrS'. We may safely consume
# everything except that last byte, but this require to
# analyze bytes of buffer that match partial separator.
# This is slow and/or require FSM. For this case our
# implementation is not optimal, since require rescanning
# of data that is known to not belong to separator. In
# real world, separator will not be so long to notice
# performance problems. Even when reading MIME-encoded
# messages :)
# `offset` is the number of bytes from the beginning of the buffer
# where there is no occurrence of `separator`.
offset = 0
# Loop until we find `separator` in the buffer, exceed the buffer size,
# or an EOF has happened.
while True:
buflen = len(self._buffer)
# Check if we now have enough data in the buffer for `separator` to
# fit.
if buflen - offset >= seplen:
isep = self._buffer.find(separator, offset)
if isep != -1:
# `separator` is in the buffer. `isep` will be used later
# to retrieve the data.
break
# see upper comment for explanation.
offset = buflen + 1 - seplen
if offset > self._limit:
raise exceptions.LimitOverrunError(
'Separator is not found, and chunk exceed the limit',
offset)
# Complete message (with full separator) may be present in buffer
# even when EOF flag is set. This may happen when the last chunk
# adds data which makes separator be found. That's why we check for
# EOF *ater* inspecting the buffer.
if self._eof:
chunk = bytes(self._buffer)
self._buffer.clear()
raise exceptions.IncompleteReadError(chunk, None)
# _wait_for_data() will resume reading if stream was paused.
await self._wait_for_data('readuntil')
if isep > self._limit:
raise exceptions.LimitOverrunError(
'Separator is found, but chunk is longer than limit', isep)
chunk = self._buffer[:isep + seplen]
del self._buffer[:isep + seplen]
self._maybe_resume_transport()
return bytes(chunk)
async def read(self, n=-1):
"""Read up to `n` bytes from the stream.
If n is not provided, or set to -1, read until EOF and return all read
bytes. If the EOF was received and the internal buffer is empty, return
an empty bytes object.
If n is zero, return empty bytes object immediately.
If n is positive, this function try to read `n` bytes, and may return
less or equal bytes than requested, but at least one byte. If EOF was
received before any byte is read, this function returns empty byte
object.
Returned value is not limited with limit, configured at stream
creation.
If stream was paused, this function will automatically resume it if
needed.
"""
if self._exception is not None:
raise self._exception
if n == 0:
return b''
if n < 0:
# This used to just loop creating a new waiter hoping to
# collect everything in self._buffer, but that would
# deadlock if the subprocess sends more than self.limit
# bytes. So just call self.read(self._limit) until EOF.
blocks = []
while True:
block = await self.read(self._limit)
if not block:
break
blocks.append(block)
return b''.join(blocks)
if not self._buffer and not self._eof:
await self._wait_for_data('read')
# This will work right even if buffer is less than n bytes
data = bytes(self._buffer[:n])
del self._buffer[:n]
self._maybe_resume_transport()
return data
async def readexactly(self, n):
"""Read exactly `n` bytes.
Raise an IncompleteReadError if EOF is reached before `n` bytes can be
read. The IncompleteReadError.partial attribute of the exception will
contain the partial read bytes.
if n is zero, return empty bytes object.
Returned value is not limited with limit, configured at stream
creation.
If stream was paused, this function will automatically resume it if
needed.
"""
if n < 0:
raise ValueError('readexactly size can not be less than zero')
if self._exception is not None:
raise self._exception
if n == 0:
return b''
while len(self._buffer) < n:
if self._eof:
incomplete = bytes(self._buffer)
self._buffer.clear()
raise exceptions.IncompleteReadError(incomplete, n)
await self._wait_for_data('readexactly')
if len(self._buffer) == n:
data = bytes(self._buffer)
self._buffer.clear()
else:
data = bytes(self._buffer[:n])
del self._buffer[:n]
self._maybe_resume_transport()
return data
def __aiter__(self):
return self
async def __anext__(self):
val = await self.readline()
if val == b'':
raise StopAsyncIteration
return val

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@ -0,0 +1,241 @@
__all__ = 'create_subprocess_exec', 'create_subprocess_shell'
import subprocess
import warnings
from . import events
from . import protocols
from . import streams
from . import tasks
from .log import logger
PIPE = subprocess.PIPE
STDOUT = subprocess.STDOUT
DEVNULL = subprocess.DEVNULL
class SubprocessStreamProtocol(streams.FlowControlMixin,
protocols.SubprocessProtocol):
"""Like StreamReaderProtocol, but for a subprocess."""
def __init__(self, limit, loop):
super().__init__(loop=loop)
self._limit = limit
self.stdin = self.stdout = self.stderr = None
self._transport = None
self._process_exited = False
self._pipe_fds = []
self._stdin_closed = self._loop.create_future()
def __repr__(self):
info = [self.__class__.__name__]
if self.stdin is not None:
info.append(f'stdin={self.stdin!r}')
if self.stdout is not None:
info.append(f'stdout={self.stdout!r}')
if self.stderr is not None:
info.append(f'stderr={self.stderr!r}')
return '<{}>'.format(' '.join(info))
def connection_made(self, transport):
self._transport = transport
stdout_transport = transport.get_pipe_transport(1)
if stdout_transport is not None:
self.stdout = streams.StreamReader(limit=self._limit,
loop=self._loop)
self.stdout.set_transport(stdout_transport)
self._pipe_fds.append(1)
stderr_transport = transport.get_pipe_transport(2)
if stderr_transport is not None:
self.stderr = streams.StreamReader(limit=self._limit,
loop=self._loop)
self.stderr.set_transport(stderr_transport)
self._pipe_fds.append(2)
stdin_transport = transport.get_pipe_transport(0)
if stdin_transport is not None:
self.stdin = streams.StreamWriter(stdin_transport,
protocol=self,
reader=None,
loop=self._loop)
def pipe_data_received(self, fd, data):
if fd == 1:
reader = self.stdout
elif fd == 2:
reader = self.stderr
else:
reader = None
if reader is not None:
reader.feed_data(data)
def pipe_connection_lost(self, fd, exc):
if fd == 0:
pipe = self.stdin
if pipe is not None:
pipe.close()
self.connection_lost(exc)
if exc is None:
self._stdin_closed.set_result(None)
else:
self._stdin_closed.set_exception(exc)
return
if fd == 1:
reader = self.stdout
elif fd == 2:
reader = self.stderr
else:
reader = None
if reader is not None:
if exc is None:
reader.feed_eof()
else:
reader.set_exception(exc)
if fd in self._pipe_fds:
self._pipe_fds.remove(fd)
self._maybe_close_transport()
def process_exited(self):
self._process_exited = True
self._maybe_close_transport()
def _maybe_close_transport(self):
if len(self._pipe_fds) == 0 and self._process_exited:
self._transport.close()
self._transport = None
def _get_close_waiter(self, stream):
if stream is self.stdin:
return self._stdin_closed
class Process:
def __init__(self, transport, protocol, loop):
self._transport = transport
self._protocol = protocol
self._loop = loop
self.stdin = protocol.stdin
self.stdout = protocol.stdout
self.stderr = protocol.stderr
self.pid = transport.get_pid()
def __repr__(self):
return f'<{self.__class__.__name__} {self.pid}>'
@property
def returncode(self):
return self._transport.get_returncode()
async def wait(self):
"""Wait until the process exit and return the process return code."""
return await self._transport._wait()
def send_signal(self, signal):
self._transport.send_signal(signal)
def terminate(self):
self._transport.terminate()
def kill(self):
self._transport.kill()
async def _feed_stdin(self, input):
debug = self._loop.get_debug()
self.stdin.write(input)
if debug:
logger.debug(
'%r communicate: feed stdin (%s bytes)', self, len(input))
try:
await self.stdin.drain()
except (BrokenPipeError, ConnectionResetError) as exc:
# communicate() ignores BrokenPipeError and ConnectionResetError
if debug:
logger.debug('%r communicate: stdin got %r', self, exc)
if debug:
logger.debug('%r communicate: close stdin', self)
self.stdin.close()
async def _noop(self):
return None
async def _read_stream(self, fd):
transport = self._transport.get_pipe_transport(fd)
if fd == 2:
stream = self.stderr
else:
assert fd == 1
stream = self.stdout
if self._loop.get_debug():
name = 'stdout' if fd == 1 else 'stderr'
logger.debug('%r communicate: read %s', self, name)
output = await stream.read()
if self._loop.get_debug():
name = 'stdout' if fd == 1 else 'stderr'
logger.debug('%r communicate: close %s', self, name)
transport.close()
return output
async def communicate(self, input=None):
if input is not None:
stdin = self._feed_stdin(input)
else:
stdin = self._noop()
if self.stdout is not None:
stdout = self._read_stream(1)
else:
stdout = self._noop()
if self.stderr is not None:
stderr = self._read_stream(2)
else:
stderr = self._noop()
stdin, stdout, stderr = await tasks.gather(stdin, stdout, stderr,
loop=self._loop)
await self.wait()
return (stdout, stderr)
async def create_subprocess_shell(cmd, stdin=None, stdout=None, stderr=None,
loop=None, limit=streams._DEFAULT_LIMIT,
**kwds):
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8 "
"and scheduled for removal in Python 3.10.",
DeprecationWarning,
stacklevel=2
)
protocol_factory = lambda: SubprocessStreamProtocol(limit=limit,
loop=loop)
transport, protocol = await loop.subprocess_shell(
protocol_factory,
cmd, stdin=stdin, stdout=stdout,
stderr=stderr, **kwds)
return Process(transport, protocol, loop)
async def create_subprocess_exec(program, *args, stdin=None, stdout=None,
stderr=None, loop=None,
limit=streams._DEFAULT_LIMIT, **kwds):
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8 "
"and scheduled for removal in Python 3.10.",
DeprecationWarning,
stacklevel=2
)
protocol_factory = lambda: SubprocessStreamProtocol(limit=limit,
loop=loop)
transport, protocol = await loop.subprocess_exec(
protocol_factory,
program, *args,
stdin=stdin, stdout=stdout,
stderr=stderr, **kwds)
return Process(transport, protocol, loop)

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@ -0,0 +1,985 @@
"""Support for tasks, coroutines and the scheduler."""
__all__ = (
'Task', 'create_task',
'FIRST_COMPLETED', 'FIRST_EXCEPTION', 'ALL_COMPLETED',
'wait', 'wait_for', 'as_completed', 'sleep',
'gather', 'shield', 'ensure_future', 'run_coroutine_threadsafe',
'current_task', 'all_tasks',
'_register_task', '_unregister_task', '_enter_task', '_leave_task',
)
import concurrent.futures
import contextvars
import functools
import inspect
import itertools
import types
import warnings
import weakref
from . import base_tasks
from . import coroutines
from . import events
from . import exceptions
from . import futures
from .coroutines import _is_coroutine
# Helper to generate new task names
# This uses itertools.count() instead of a "+= 1" operation because the latter
# is not thread safe. See bpo-11866 for a longer explanation.
_task_name_counter = itertools.count(1).__next__
def current_task(loop=None):
"""Return a currently executed task."""
if loop is None:
loop = events.get_running_loop()
return _current_tasks.get(loop)
def all_tasks(loop=None):
"""Return a set of all tasks for the loop."""
if loop is None:
loop = events.get_running_loop()
# Looping over a WeakSet (_all_tasks) isn't safe as it can be updated from another
# thread while we do so. Therefore we cast it to list prior to filtering. The list
# cast itself requires iteration, so we repeat it several times ignoring
# RuntimeErrors (which are not very likely to occur). See issues 34970 and 36607 for
# details.
i = 0
while True:
try:
tasks = list(_all_tasks)
except RuntimeError:
i += 1
if i >= 1000:
raise
else:
break
return {t for t in tasks
if futures._get_loop(t) is loop and not t.done()}
def _all_tasks_compat(loop=None):
# Different from "all_task()" by returning *all* Tasks, including
# the completed ones. Used to implement deprecated "Tasks.all_task()"
# method.
if loop is None:
loop = events.get_event_loop()
# Looping over a WeakSet (_all_tasks) isn't safe as it can be updated from another
# thread while we do so. Therefore we cast it to list prior to filtering. The list
# cast itself requires iteration, so we repeat it several times ignoring
# RuntimeErrors (which are not very likely to occur). See issues 34970 and 36607 for
# details.
i = 0
while True:
try:
tasks = list(_all_tasks)
except RuntimeError:
i += 1
if i >= 1000:
raise
else:
break
return {t for t in tasks if futures._get_loop(t) is loop}
def _set_task_name(task, name):
if name is not None:
try:
set_name = task.set_name
except AttributeError:
pass
else:
set_name(name)
class Task(futures._PyFuture): # Inherit Python Task implementation
# from a Python Future implementation.
"""A coroutine wrapped in a Future."""
# An important invariant maintained while a Task not done:
#
# - Either _fut_waiter is None, and _step() is scheduled;
# - or _fut_waiter is some Future, and _step() is *not* scheduled.
#
# The only transition from the latter to the former is through
# _wakeup(). When _fut_waiter is not None, one of its callbacks
# must be _wakeup().
# If False, don't log a message if the task is destroyed whereas its
# status is still pending
_log_destroy_pending = True
def __init__(self, coro, *, loop=None, name=None):
super().__init__(loop=loop)
if self._source_traceback:
del self._source_traceback[-1]
if not coroutines.iscoroutine(coro):
# raise after Future.__init__(), attrs are required for __del__
# prevent logging for pending task in __del__
self._log_destroy_pending = False
raise TypeError(f"a coroutine was expected, got {coro!r}")
if name is None:
self._name = f'Task-{_task_name_counter()}'
else:
self._name = str(name)
self._must_cancel = False
self._fut_waiter = None
self._coro = coro
self._context = contextvars.copy_context()
self._loop.call_soon(self.__step, context=self._context)
_register_task(self)
def __del__(self):
if self._state == futures._PENDING and self._log_destroy_pending:
context = {
'task': self,
'message': 'Task was destroyed but it is pending!',
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
super().__del__()
def __class_getitem__(cls, type):
return cls
def _repr_info(self):
return base_tasks._task_repr_info(self)
def get_coro(self):
return self._coro
def get_name(self):
return self._name
def set_name(self, value):
self._name = str(value)
def set_result(self, result):
raise RuntimeError('Task does not support set_result operation')
def set_exception(self, exception):
raise RuntimeError('Task does not support set_exception operation')
def get_stack(self, *, limit=None):
"""Return the list of stack frames for this task's coroutine.
If the coroutine is not done, this returns the stack where it is
suspended. If the coroutine has completed successfully or was
cancelled, this returns an empty list. If the coroutine was
terminated by an exception, this returns the list of traceback
frames.
The frames are always ordered from oldest to newest.
The optional limit gives the maximum number of frames to
return; by default all available frames are returned. Its
meaning differs depending on whether a stack or a traceback is
returned: the newest frames of a stack are returned, but the
oldest frames of a traceback are returned. (This matches the
behavior of the traceback module.)
For reasons beyond our control, only one stack frame is
returned for a suspended coroutine.
"""
return base_tasks._task_get_stack(self, limit)
def print_stack(self, *, limit=None, file=None):
"""Print the stack or traceback for this task's coroutine.
This produces output similar to that of the traceback module,
for the frames retrieved by get_stack(). The limit argument
is passed to get_stack(). The file argument is an I/O stream
to which the output is written; by default output is written
to sys.stderr.
"""
return base_tasks._task_print_stack(self, limit, file)
def cancel(self, msg=None):
"""Request that this task cancel itself.
This arranges for a CancelledError to be thrown into the
wrapped coroutine on the next cycle through the event loop.
The coroutine then has a chance to clean up or even deny
the request using try/except/finally.
Unlike Future.cancel, this does not guarantee that the
task will be cancelled: the exception might be caught and
acted upon, delaying cancellation of the task or preventing
cancellation completely. The task may also return a value or
raise a different exception.
Immediately after this method is called, Task.cancelled() will
not return True (unless the task was already cancelled). A
task will be marked as cancelled when the wrapped coroutine
terminates with a CancelledError exception (even if cancel()
was not called).
"""
self._log_traceback = False
if self.done():
return False
if self._fut_waiter is not None:
if self._fut_waiter.cancel(msg=msg):
# Leave self._fut_waiter; it may be a Task that
# catches and ignores the cancellation so we may have
# to cancel it again later.
return True
# It must be the case that self.__step is already scheduled.
self._must_cancel = True
self._cancel_message = msg
return True
def __step(self, exc=None):
if self.done():
raise exceptions.InvalidStateError(
f'_step(): already done: {self!r}, {exc!r}')
if self._must_cancel:
if not isinstance(exc, exceptions.CancelledError):
exc = self._make_cancelled_error()
self._must_cancel = False
coro = self._coro
self._fut_waiter = None
_enter_task(self._loop, self)
# Call either coro.throw(exc) or coro.send(None).
try:
if exc is None:
# We use the `send` method directly, because coroutines
# don't have `__iter__` and `__next__` methods.
result = coro.send(None)
else:
result = coro.throw(exc)
except StopIteration as exc:
if self._must_cancel:
# Task is cancelled right before coro stops.
self._must_cancel = False
super().cancel(msg=self._cancel_message)
else:
super().set_result(exc.value)
except exceptions.CancelledError as exc:
# Save the original exception so we can chain it later.
self._cancelled_exc = exc
super().cancel() # I.e., Future.cancel(self).
except (KeyboardInterrupt, SystemExit) as exc:
super().set_exception(exc)
raise
except BaseException as exc:
super().set_exception(exc)
else:
blocking = getattr(result, '_asyncio_future_blocking', None)
if blocking is not None:
# Yielded Future must come from Future.__iter__().
if futures._get_loop(result) is not self._loop:
new_exc = RuntimeError(
f'Task {self!r} got Future '
f'{result!r} attached to a different loop')
self._loop.call_soon(
self.__step, new_exc, context=self._context)
elif blocking:
if result is self:
new_exc = RuntimeError(
f'Task cannot await on itself: {self!r}')
self._loop.call_soon(
self.__step, new_exc, context=self._context)
else:
result._asyncio_future_blocking = False
result.add_done_callback(
self.__wakeup, context=self._context)
self._fut_waiter = result
if self._must_cancel:
if self._fut_waiter.cancel(
msg=self._cancel_message):
self._must_cancel = False
else:
new_exc = RuntimeError(
f'yield was used instead of yield from '
f'in task {self!r} with {result!r}')
self._loop.call_soon(
self.__step, new_exc, context=self._context)
elif result is None:
# Bare yield relinquishes control for one event loop iteration.
self._loop.call_soon(self.__step, context=self._context)
elif inspect.isgenerator(result):
# Yielding a generator is just wrong.
new_exc = RuntimeError(
f'yield was used instead of yield from for '
f'generator in task {self!r} with {result!r}')
self._loop.call_soon(
self.__step, new_exc, context=self._context)
else:
# Yielding something else is an error.
new_exc = RuntimeError(f'Task got bad yield: {result!r}')
self._loop.call_soon(
self.__step, new_exc, context=self._context)
finally:
_leave_task(self._loop, self)
self = None # Needed to break cycles when an exception occurs.
def __wakeup(self, future):
try:
future.result()
except BaseException as exc:
# This may also be a cancellation.
self.__step(exc)
else:
# Don't pass the value of `future.result()` explicitly,
# as `Future.__iter__` and `Future.__await__` don't need it.
# If we call `_step(value, None)` instead of `_step()`,
# Python eval loop would use `.send(value)` method call,
# instead of `__next__()`, which is slower for futures
# that return non-generator iterators from their `__iter__`.
self.__step()
self = None # Needed to break cycles when an exception occurs.
_PyTask = Task
try:
import _asyncio
except ImportError:
pass
else:
# _CTask is needed for tests.
Task = _CTask = _asyncio.Task
def create_task(coro, *, name=None):
"""Schedule the execution of a coroutine object in a spawn task.
Return a Task object.
"""
loop = events.get_running_loop()
task = loop.create_task(coro)
_set_task_name(task, name)
return task
# wait() and as_completed() similar to those in PEP 3148.
FIRST_COMPLETED = concurrent.futures.FIRST_COMPLETED
FIRST_EXCEPTION = concurrent.futures.FIRST_EXCEPTION
ALL_COMPLETED = concurrent.futures.ALL_COMPLETED
async def wait(fs, *, loop=None, timeout=None, return_when=ALL_COMPLETED):
"""Wait for the Futures and coroutines given by fs to complete.
The fs iterable must not be empty.
Coroutines will be wrapped in Tasks.
Returns two sets of Future: (done, pending).
Usage:
done, pending = await asyncio.wait(fs)
Note: This does not raise TimeoutError! Futures that aren't done
when the timeout occurs are returned in the second set.
"""
if futures.isfuture(fs) or coroutines.iscoroutine(fs):
raise TypeError(f"expect a list of futures, not {type(fs).__name__}")
if not fs:
raise ValueError('Set of coroutines/Futures is empty.')
if return_when not in (FIRST_COMPLETED, FIRST_EXCEPTION, ALL_COMPLETED):
raise ValueError(f'Invalid return_when value: {return_when}')
if loop is None:
loop = events.get_running_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
fs = set(fs)
if any(coroutines.iscoroutine(f) for f in fs):
warnings.warn("The explicit passing of coroutine objects to "
"asyncio.wait() is deprecated since Python 3.8, and "
"scheduled for removal in Python 3.11.",
DeprecationWarning, stacklevel=2)
fs = {ensure_future(f, loop=loop) for f in fs}
return await _wait(fs, timeout, return_when, loop)
def _release_waiter(waiter, *args):
if not waiter.done():
waiter.set_result(None)
async def wait_for(fut, timeout, *, loop=None):
"""Wait for the single Future or coroutine to complete, with timeout.
Coroutine will be wrapped in Task.
Returns result of the Future or coroutine. When a timeout occurs,
it cancels the task and raises TimeoutError. To avoid the task
cancellation, wrap it in shield().
If the wait is cancelled, the task is also cancelled.
This function is a coroutine.
"""
if loop is None:
loop = events.get_running_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
if timeout is None:
return await fut
if timeout <= 0:
fut = ensure_future(fut, loop=loop)
if fut.done():
return fut.result()
await _cancel_and_wait(fut, loop=loop)
try:
fut.result()
except exceptions.CancelledError as exc:
raise exceptions.TimeoutError() from exc
else:
raise exceptions.TimeoutError()
waiter = loop.create_future()
timeout_handle = loop.call_later(timeout, _release_waiter, waiter)
cb = functools.partial(_release_waiter, waiter)
fut = ensure_future(fut, loop=loop)
fut.add_done_callback(cb)
try:
# wait until the future completes or the timeout
try:
await waiter
except exceptions.CancelledError:
if fut.done():
return fut.result()
else:
fut.remove_done_callback(cb)
# We must ensure that the task is not running
# after wait_for() returns.
# See https://bugs.python.org/issue32751
await _cancel_and_wait(fut, loop=loop)
raise
if fut.done():
return fut.result()
else:
fut.remove_done_callback(cb)
# We must ensure that the task is not running
# after wait_for() returns.
# See https://bugs.python.org/issue32751
await _cancel_and_wait(fut, loop=loop)
# In case task cancellation failed with some
# exception, we should re-raise it
# See https://bugs.python.org/issue40607
try:
fut.result()
except exceptions.CancelledError as exc:
raise exceptions.TimeoutError() from exc
else:
raise exceptions.TimeoutError()
finally:
timeout_handle.cancel()
async def _wait(fs, timeout, return_when, loop):
"""Internal helper for wait().
The fs argument must be a collection of Futures.
"""
assert fs, 'Set of Futures is empty.'
waiter = loop.create_future()
timeout_handle = None
if timeout is not None:
timeout_handle = loop.call_later(timeout, _release_waiter, waiter)
counter = len(fs)
def _on_completion(f):
nonlocal counter
counter -= 1
if (counter <= 0 or
return_when == FIRST_COMPLETED or
return_when == FIRST_EXCEPTION and (not f.cancelled() and
f.exception() is not None)):
if timeout_handle is not None:
timeout_handle.cancel()
if not waiter.done():
waiter.set_result(None)
for f in fs:
f.add_done_callback(_on_completion)
try:
await waiter
finally:
if timeout_handle is not None:
timeout_handle.cancel()
for f in fs:
f.remove_done_callback(_on_completion)
done, pending = set(), set()
for f in fs:
if f.done():
done.add(f)
else:
pending.add(f)
return done, pending
async def _cancel_and_wait(fut, loop):
"""Cancel the *fut* future or task and wait until it completes."""
waiter = loop.create_future()
cb = functools.partial(_release_waiter, waiter)
fut.add_done_callback(cb)
try:
fut.cancel()
# We cannot wait on *fut* directly to make
# sure _cancel_and_wait itself is reliably cancellable.
await waiter
finally:
fut.remove_done_callback(cb)
# This is *not* a @coroutine! It is just an iterator (yielding Futures).
def as_completed(fs, *, loop=None, timeout=None):
"""Return an iterator whose values are coroutines.
When waiting for the yielded coroutines you'll get the results (or
exceptions!) of the original Futures (or coroutines), in the order
in which and as soon as they complete.
This differs from PEP 3148; the proper way to use this is:
for f in as_completed(fs):
result = await f # The 'await' may raise.
# Use result.
If a timeout is specified, the 'await' will raise
TimeoutError when the timeout occurs before all Futures are done.
Note: The futures 'f' are not necessarily members of fs.
"""
if futures.isfuture(fs) or coroutines.iscoroutine(fs):
raise TypeError(f"expect an iterable of futures, not {type(fs).__name__}")
from .queues import Queue # Import here to avoid circular import problem.
done = Queue(loop=loop)
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
todo = {ensure_future(f, loop=loop) for f in set(fs)}
timeout_handle = None
def _on_timeout():
for f in todo:
f.remove_done_callback(_on_completion)
done.put_nowait(None) # Queue a dummy value for _wait_for_one().
todo.clear() # Can't do todo.remove(f) in the loop.
def _on_completion(f):
if not todo:
return # _on_timeout() was here first.
todo.remove(f)
done.put_nowait(f)
if not todo and timeout_handle is not None:
timeout_handle.cancel()
async def _wait_for_one():
f = await done.get()
if f is None:
# Dummy value from _on_timeout().
raise exceptions.TimeoutError
return f.result() # May raise f.exception().
for f in todo:
f.add_done_callback(_on_completion)
if todo and timeout is not None:
timeout_handle = loop.call_later(timeout, _on_timeout)
for _ in range(len(todo)):
yield _wait_for_one()
@types.coroutine
def __sleep0():
"""Skip one event loop run cycle.
This is a private helper for 'asyncio.sleep()', used
when the 'delay' is set to 0. It uses a bare 'yield'
expression (which Task.__step knows how to handle)
instead of creating a Future object.
"""
yield
async def sleep(delay, result=None, *, loop=None):
"""Coroutine that completes after a given time (in seconds)."""
if delay <= 0:
await __sleep0()
return result
if loop is None:
loop = events.get_running_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
future = loop.create_future()
h = loop.call_later(delay,
futures._set_result_unless_cancelled,
future, result)
try:
return await future
finally:
h.cancel()
def ensure_future(coro_or_future, *, loop=None):
"""Wrap a coroutine or an awaitable in a future.
If the argument is a Future, it is returned directly.
"""
if coroutines.iscoroutine(coro_or_future):
if loop is None:
loop = events.get_event_loop()
task = loop.create_task(coro_or_future)
if task._source_traceback:
del task._source_traceback[-1]
return task
elif futures.isfuture(coro_or_future):
if loop is not None and loop is not futures._get_loop(coro_or_future):
raise ValueError('The future belongs to a different loop than '
'the one specified as the loop argument')
return coro_or_future
elif inspect.isawaitable(coro_or_future):
return ensure_future(_wrap_awaitable(coro_or_future), loop=loop)
else:
raise TypeError('An asyncio.Future, a coroutine or an awaitable is '
'required')
@types.coroutine
def _wrap_awaitable(awaitable):
"""Helper for asyncio.ensure_future().
Wraps awaitable (an object with __await__) into a coroutine
that will later be wrapped in a Task by ensure_future().
"""
return (yield from awaitable.__await__())
_wrap_awaitable._is_coroutine = _is_coroutine
class _GatheringFuture(futures.Future):
"""Helper for gather().
This overrides cancel() to cancel all the children and act more
like Task.cancel(), which doesn't immediately mark itself as
cancelled.
"""
def __init__(self, children, *, loop=None):
super().__init__(loop=loop)
self._children = children
self._cancel_requested = False
def cancel(self, msg=None):
if self.done():
return False
ret = False
for child in self._children:
if child.cancel(msg=msg):
ret = True
if ret:
# If any child tasks were actually cancelled, we should
# propagate the cancellation request regardless of
# *return_exceptions* argument. See issue 32684.
self._cancel_requested = True
return ret
def gather(*coros_or_futures, loop=None, return_exceptions=False):
"""Return a future aggregating results from the given coroutines/futures.
Coroutines will be wrapped in a future and scheduled in the event
loop. They will not necessarily be scheduled in the same order as
passed in.
All futures must share the same event loop. If all the tasks are
done successfully, the returned future's result is the list of
results (in the order of the original sequence, not necessarily
the order of results arrival). If *return_exceptions* is True,
exceptions in the tasks are treated the same as successful
results, and gathered in the result list; otherwise, the first
raised exception will be immediately propagated to the returned
future.
Cancellation: if the outer Future is cancelled, all children (that
have not completed yet) are also cancelled. If any child is
cancelled, this is treated as if it raised CancelledError --
the outer Future is *not* cancelled in this case. (This is to
prevent the cancellation of one child to cause other children to
be cancelled.)
If *return_exceptions* is False, cancelling gather() after it
has been marked done won't cancel any submitted awaitables.
For instance, gather can be marked done after propagating an
exception to the caller, therefore, calling ``gather.cancel()``
after catching an exception (raised by one of the awaitables) from
gather won't cancel any other awaitables.
"""
if not coros_or_futures:
if loop is None:
loop = events.get_event_loop()
else:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
outer = loop.create_future()
outer.set_result([])
return outer
def _done_callback(fut):
nonlocal nfinished
nfinished += 1
if outer.done():
if not fut.cancelled():
# Mark exception retrieved.
fut.exception()
return
if not return_exceptions:
if fut.cancelled():
# Check if 'fut' is cancelled first, as
# 'fut.exception()' will *raise* a CancelledError
# instead of returning it.
exc = fut._make_cancelled_error()
outer.set_exception(exc)
return
else:
exc = fut.exception()
if exc is not None:
outer.set_exception(exc)
return
if nfinished == nfuts:
# All futures are done; create a list of results
# and set it to the 'outer' future.
results = []
for fut in children:
if fut.cancelled():
# Check if 'fut' is cancelled first, as 'fut.exception()'
# will *raise* a CancelledError instead of returning it.
# Also, since we're adding the exception return value
# to 'results' instead of raising it, don't bother
# setting __context__. This also lets us preserve
# calling '_make_cancelled_error()' at most once.
res = exceptions.CancelledError(
'' if fut._cancel_message is None else
fut._cancel_message)
else:
res = fut.exception()
if res is None:
res = fut.result()
results.append(res)
if outer._cancel_requested:
# If gather is being cancelled we must propagate the
# cancellation regardless of *return_exceptions* argument.
# See issue 32684.
exc = fut._make_cancelled_error()
outer.set_exception(exc)
else:
outer.set_result(results)
arg_to_fut = {}
children = []
nfuts = 0
nfinished = 0
for arg in coros_or_futures:
if arg not in arg_to_fut:
fut = ensure_future(arg, loop=loop)
if loop is None:
loop = futures._get_loop(fut)
if fut is not arg:
# 'arg' was not a Future, therefore, 'fut' is a new
# Future created specifically for 'arg'. Since the caller
# can't control it, disable the "destroy pending task"
# warning.
fut._log_destroy_pending = False
nfuts += 1
arg_to_fut[arg] = fut
fut.add_done_callback(_done_callback)
else:
# There's a duplicate Future object in coros_or_futures.
fut = arg_to_fut[arg]
children.append(fut)
outer = _GatheringFuture(children, loop=loop)
return outer
def shield(arg, *, loop=None):
"""Wait for a future, shielding it from cancellation.
The statement
res = await shield(something())
is exactly equivalent to the statement
res = await something()
*except* that if the coroutine containing it is cancelled, the
task running in something() is not cancelled. From the POV of
something(), the cancellation did not happen. But its caller is
still cancelled, so the yield-from expression still raises
CancelledError. Note: If something() is cancelled by other means
this will still cancel shield().
If you want to completely ignore cancellation (not recommended)
you can combine shield() with a try/except clause, as follows:
try:
res = await shield(something())
except CancelledError:
res = None
"""
if loop is not None:
warnings.warn("The loop argument is deprecated since Python 3.8, "
"and scheduled for removal in Python 3.10.",
DeprecationWarning, stacklevel=2)
inner = ensure_future(arg, loop=loop)
if inner.done():
# Shortcut.
return inner
loop = futures._get_loop(inner)
outer = loop.create_future()
def _inner_done_callback(inner):
if outer.cancelled():
if not inner.cancelled():
# Mark inner's result as retrieved.
inner.exception()
return
if inner.cancelled():
outer.cancel()
else:
exc = inner.exception()
if exc is not None:
outer.set_exception(exc)
else:
outer.set_result(inner.result())
def _outer_done_callback(outer):
if not inner.done():
inner.remove_done_callback(_inner_done_callback)
inner.add_done_callback(_inner_done_callback)
outer.add_done_callback(_outer_done_callback)
return outer
def run_coroutine_threadsafe(coro, loop):
"""Submit a coroutine object to a given event loop.
Return a concurrent.futures.Future to access the result.
"""
if not coroutines.iscoroutine(coro):
raise TypeError('A coroutine object is required')
future = concurrent.futures.Future()
def callback():
try:
futures._chain_future(ensure_future(coro, loop=loop), future)
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
if future.set_running_or_notify_cancel():
future.set_exception(exc)
raise
loop.call_soon_threadsafe(callback)
return future
# WeakSet containing all alive tasks.
_all_tasks = weakref.WeakSet()
# Dictionary containing tasks that are currently active in
# all running event loops. {EventLoop: Task}
_current_tasks = {}
def _register_task(task):
"""Register a new task in asyncio as executed by loop."""
_all_tasks.add(task)
def _enter_task(loop, task):
current_task = _current_tasks.get(loop)
if current_task is not None:
raise RuntimeError(f"Cannot enter into task {task!r} while another "
f"task {current_task!r} is being executed.")
_current_tasks[loop] = task
def _leave_task(loop, task):
current_task = _current_tasks.get(loop)
if current_task is not task:
raise RuntimeError(f"Leaving task {task!r} does not match "
f"the current task {current_task!r}.")
del _current_tasks[loop]
def _unregister_task(task):
"""Unregister a task."""
_all_tasks.discard(task)
_py_register_task = _register_task
_py_unregister_task = _unregister_task
_py_enter_task = _enter_task
_py_leave_task = _leave_task
try:
from _asyncio import (_register_task, _unregister_task,
_enter_task, _leave_task,
_all_tasks, _current_tasks)
except ImportError:
pass
else:
_c_register_task = _register_task
_c_unregister_task = _unregister_task
_c_enter_task = _enter_task
_c_leave_task = _leave_task

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@ -0,0 +1,25 @@
"""High-level support for working with threads in asyncio"""
import functools
import contextvars
from . import events
__all__ = "to_thread",
async def to_thread(func, /, *args, **kwargs):
"""Asynchronously run function *func* in a separate thread.
Any *args and **kwargs supplied for this function are directly passed
to *func*. Also, the current :class:`contextvars.Context` is propogated,
allowing context variables from the main thread to be accessed in the
separate thread.
Return a coroutine that can be awaited to get the eventual result of *func*.
"""
loop = events.get_running_loop()
ctx = contextvars.copy_context()
func_call = functools.partial(ctx.run, func, *args, **kwargs)
return await loop.run_in_executor(None, func_call)

View File

@ -0,0 +1,329 @@
"""Abstract Transport class."""
__all__ = (
'BaseTransport', 'ReadTransport', 'WriteTransport',
'Transport', 'DatagramTransport', 'SubprocessTransport',
)
class BaseTransport:
"""Base class for transports."""
__slots__ = ('_extra',)
def __init__(self, extra=None):
if extra is None:
extra = {}
self._extra = extra
def get_extra_info(self, name, default=None):
"""Get optional transport information."""
return self._extra.get(name, default)
def is_closing(self):
"""Return True if the transport is closing or closed."""
raise NotImplementedError
def close(self):
"""Close the transport.
Buffered data will be flushed asynchronously. No more data
will be received. After all buffered data is flushed, the
protocol's connection_lost() method will (eventually) be
called with None as its argument.
"""
raise NotImplementedError
def set_protocol(self, protocol):
"""Set a new protocol."""
raise NotImplementedError
def get_protocol(self):
"""Return the current protocol."""
raise NotImplementedError
class ReadTransport(BaseTransport):
"""Interface for read-only transports."""
__slots__ = ()
def is_reading(self):
"""Return True if the transport is receiving."""
raise NotImplementedError
def pause_reading(self):
"""Pause the receiving end.
No data will be passed to the protocol's data_received()
method until resume_reading() is called.
"""
raise NotImplementedError
def resume_reading(self):
"""Resume the receiving end.
Data received will once again be passed to the protocol's
data_received() method.
"""
raise NotImplementedError
class WriteTransport(BaseTransport):
"""Interface for write-only transports."""
__slots__ = ()
def set_write_buffer_limits(self, high=None, low=None):
"""Set the high- and low-water limits for write flow control.
These two values control when to call the protocol's
pause_writing() and resume_writing() methods. If specified,
the low-water limit must be less than or equal to the
high-water limit. Neither value can be negative.
The defaults are implementation-specific. If only the
high-water limit is given, the low-water limit defaults to an
implementation-specific value less than or equal to the
high-water limit. Setting high to zero forces low to zero as
well, and causes pause_writing() to be called whenever the
buffer becomes non-empty. Setting low to zero causes
resume_writing() to be called only once the buffer is empty.
Use of zero for either limit is generally sub-optimal as it
reduces opportunities for doing I/O and computation
concurrently.
"""
raise NotImplementedError
def get_write_buffer_size(self):
"""Return the current size of the write buffer."""
raise NotImplementedError
def write(self, data):
"""Write some data bytes to the transport.
This does not block; it buffers the data and arranges for it
to be sent out asynchronously.
"""
raise NotImplementedError
def writelines(self, list_of_data):
"""Write a list (or any iterable) of data bytes to the transport.
The default implementation concatenates the arguments and
calls write() on the result.
"""
data = b''.join(list_of_data)
self.write(data)
def write_eof(self):
"""Close the write end after flushing buffered data.
(This is like typing ^D into a UNIX program reading from stdin.)
Data may still be received.
"""
raise NotImplementedError
def can_write_eof(self):
"""Return True if this transport supports write_eof(), False if not."""
raise NotImplementedError
def abort(self):
"""Close the transport immediately.
Buffered data will be lost. No more data will be received.
The protocol's connection_lost() method will (eventually) be
called with None as its argument.
"""
raise NotImplementedError
class Transport(ReadTransport, WriteTransport):
"""Interface representing a bidirectional transport.
There may be several implementations, but typically, the user does
not implement new transports; rather, the platform provides some
useful transports that are implemented using the platform's best
practices.
The user never instantiates a transport directly; they call a
utility function, passing it a protocol factory and other
information necessary to create the transport and protocol. (E.g.
EventLoop.create_connection() or EventLoop.create_server().)
The utility function will asynchronously create a transport and a
protocol and hook them up by calling the protocol's
connection_made() method, passing it the transport.
The implementation here raises NotImplemented for every method
except writelines(), which calls write() in a loop.
"""
__slots__ = ()
class DatagramTransport(BaseTransport):
"""Interface for datagram (UDP) transports."""
__slots__ = ()
def sendto(self, data, addr=None):
"""Send data to the transport.
This does not block; it buffers the data and arranges for it
to be sent out asynchronously.
addr is target socket address.
If addr is None use target address pointed on transport creation.
"""
raise NotImplementedError
def abort(self):
"""Close the transport immediately.
Buffered data will be lost. No more data will be received.
The protocol's connection_lost() method will (eventually) be
called with None as its argument.
"""
raise NotImplementedError
class SubprocessTransport(BaseTransport):
__slots__ = ()
def get_pid(self):
"""Get subprocess id."""
raise NotImplementedError
def get_returncode(self):
"""Get subprocess returncode.
See also
http://docs.python.org/3/library/subprocess#subprocess.Popen.returncode
"""
raise NotImplementedError
def get_pipe_transport(self, fd):
"""Get transport for pipe with number fd."""
raise NotImplementedError
def send_signal(self, signal):
"""Send signal to subprocess.
See also:
docs.python.org/3/library/subprocess#subprocess.Popen.send_signal
"""
raise NotImplementedError
def terminate(self):
"""Stop the subprocess.
Alias for close() method.
On Posix OSs the method sends SIGTERM to the subprocess.
On Windows the Win32 API function TerminateProcess()
is called to stop the subprocess.
See also:
http://docs.python.org/3/library/subprocess#subprocess.Popen.terminate
"""
raise NotImplementedError
def kill(self):
"""Kill the subprocess.
On Posix OSs the function sends SIGKILL to the subprocess.
On Windows kill() is an alias for terminate().
See also:
http://docs.python.org/3/library/subprocess#subprocess.Popen.kill
"""
raise NotImplementedError
class _FlowControlMixin(Transport):
"""All the logic for (write) flow control in a mix-in base class.
The subclass must implement get_write_buffer_size(). It must call
_maybe_pause_protocol() whenever the write buffer size increases,
and _maybe_resume_protocol() whenever it decreases. It may also
override set_write_buffer_limits() (e.g. to specify different
defaults).
The subclass constructor must call super().__init__(extra). This
will call set_write_buffer_limits().
The user may call set_write_buffer_limits() and
get_write_buffer_size(), and their protocol's pause_writing() and
resume_writing() may be called.
"""
__slots__ = ('_loop', '_protocol_paused', '_high_water', '_low_water')
def __init__(self, extra=None, loop=None):
super().__init__(extra)
assert loop is not None
self._loop = loop
self._protocol_paused = False
self._set_write_buffer_limits()
def _maybe_pause_protocol(self):
size = self.get_write_buffer_size()
if size <= self._high_water:
return
if not self._protocol_paused:
self._protocol_paused = True
try:
self._protocol.pause_writing()
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self._loop.call_exception_handler({
'message': 'protocol.pause_writing() failed',
'exception': exc,
'transport': self,
'protocol': self._protocol,
})
def _maybe_resume_protocol(self):
if (self._protocol_paused and
self.get_write_buffer_size() <= self._low_water):
self._protocol_paused = False
try:
self._protocol.resume_writing()
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self._loop.call_exception_handler({
'message': 'protocol.resume_writing() failed',
'exception': exc,
'transport': self,
'protocol': self._protocol,
})
def get_write_buffer_limits(self):
return (self._low_water, self._high_water)
def _set_write_buffer_limits(self, high=None, low=None):
if high is None:
if low is None:
high = 64 * 1024
else:
high = 4 * low
if low is None:
low = high // 4
if not high >= low >= 0:
raise ValueError(
f'high ({high!r}) must be >= low ({low!r}) must be >= 0')
self._high_water = high
self._low_water = low
def set_write_buffer_limits(self, high=None, low=None):
self._set_write_buffer_limits(high=high, low=low)
self._maybe_pause_protocol()
def get_write_buffer_size(self):
raise NotImplementedError

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@ -0,0 +1,206 @@
import socket
import warnings
class TransportSocket:
"""A socket-like wrapper for exposing real transport sockets.
These objects can be safely returned by APIs like
`transport.get_extra_info('socket')`. All potentially disruptive
operations (like "socket.close()") are banned.
"""
__slots__ = ('_sock',)
def __init__(self, sock: socket.socket):
self._sock = sock
def _na(self, what):
warnings.warn(
f"Using {what} on sockets returned from get_extra_info('socket') "
f"will be prohibited in asyncio 3.9. Please report your use case "
f"to bugs.python.org.",
DeprecationWarning, source=self)
@property
def family(self):
return self._sock.family
@property
def type(self):
return self._sock.type
@property
def proto(self):
return self._sock.proto
def __repr__(self):
s = (
f"<asyncio.TransportSocket fd={self.fileno()}, "
f"family={self.family!s}, type={self.type!s}, "
f"proto={self.proto}"
)
if self.fileno() != -1:
try:
laddr = self.getsockname()
if laddr:
s = f"{s}, laddr={laddr}"
except socket.error:
pass
try:
raddr = self.getpeername()
if raddr:
s = f"{s}, raddr={raddr}"
except socket.error:
pass
return f"{s}>"
def __getstate__(self):
raise TypeError("Cannot serialize asyncio.TransportSocket object")
def fileno(self):
return self._sock.fileno()
def dup(self):
return self._sock.dup()
def get_inheritable(self):
return self._sock.get_inheritable()
def shutdown(self, how):
# asyncio doesn't currently provide a high-level transport API
# to shutdown the connection.
self._sock.shutdown(how)
def getsockopt(self, *args, **kwargs):
return self._sock.getsockopt(*args, **kwargs)
def setsockopt(self, *args, **kwargs):
self._sock.setsockopt(*args, **kwargs)
def getpeername(self):
return self._sock.getpeername()
def getsockname(self):
return self._sock.getsockname()
def getsockbyname(self):
return self._sock.getsockbyname()
def accept(self):
self._na('accept() method')
return self._sock.accept()
def connect(self, *args, **kwargs):
self._na('connect() method')
return self._sock.connect(*args, **kwargs)
def connect_ex(self, *args, **kwargs):
self._na('connect_ex() method')
return self._sock.connect_ex(*args, **kwargs)
def bind(self, *args, **kwargs):
self._na('bind() method')
return self._sock.bind(*args, **kwargs)
def ioctl(self, *args, **kwargs):
self._na('ioctl() method')
return self._sock.ioctl(*args, **kwargs)
def listen(self, *args, **kwargs):
self._na('listen() method')
return self._sock.listen(*args, **kwargs)
def makefile(self):
self._na('makefile() method')
return self._sock.makefile()
def sendfile(self, *args, **kwargs):
self._na('sendfile() method')
return self._sock.sendfile(*args, **kwargs)
def close(self):
self._na('close() method')
return self._sock.close()
def detach(self):
self._na('detach() method')
return self._sock.detach()
def sendmsg_afalg(self, *args, **kwargs):
self._na('sendmsg_afalg() method')
return self._sock.sendmsg_afalg(*args, **kwargs)
def sendmsg(self, *args, **kwargs):
self._na('sendmsg() method')
return self._sock.sendmsg(*args, **kwargs)
def sendto(self, *args, **kwargs):
self._na('sendto() method')
return self._sock.sendto(*args, **kwargs)
def send(self, *args, **kwargs):
self._na('send() method')
return self._sock.send(*args, **kwargs)
def sendall(self, *args, **kwargs):
self._na('sendall() method')
return self._sock.sendall(*args, **kwargs)
def set_inheritable(self, *args, **kwargs):
self._na('set_inheritable() method')
return self._sock.set_inheritable(*args, **kwargs)
def share(self, process_id):
self._na('share() method')
return self._sock.share(process_id)
def recv_into(self, *args, **kwargs):
self._na('recv_into() method')
return self._sock.recv_into(*args, **kwargs)
def recvfrom_into(self, *args, **kwargs):
self._na('recvfrom_into() method')
return self._sock.recvfrom_into(*args, **kwargs)
def recvmsg_into(self, *args, **kwargs):
self._na('recvmsg_into() method')
return self._sock.recvmsg_into(*args, **kwargs)
def recvmsg(self, *args, **kwargs):
self._na('recvmsg() method')
return self._sock.recvmsg(*args, **kwargs)
def recvfrom(self, *args, **kwargs):
self._na('recvfrom() method')
return self._sock.recvfrom(*args, **kwargs)
def recv(self, *args, **kwargs):
self._na('recv() method')
return self._sock.recv(*args, **kwargs)
def settimeout(self, value):
if value == 0:
return
raise ValueError(
'settimeout(): only 0 timeout is allowed on transport sockets')
def gettimeout(self):
return 0
def setblocking(self, flag):
if not flag:
return
raise ValueError(
'setblocking(): transport sockets cannot be blocking')
def __enter__(self):
self._na('context manager protocol')
return self._sock.__enter__()
def __exit__(self, *err):
self._na('context manager protocol')
return self._sock.__exit__(*err)

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"""Selector and proactor event loops for Windows."""
import _overlapped
import _winapi
import errno
import math
import msvcrt
import socket
import struct
import time
import weakref
from . import events
from . import base_subprocess
from . import futures
from . import exceptions
from . import proactor_events
from . import selector_events
from . import tasks
from . import windows_utils
from .log import logger
__all__ = (
'SelectorEventLoop', 'ProactorEventLoop', 'IocpProactor',
'DefaultEventLoopPolicy', 'WindowsSelectorEventLoopPolicy',
'WindowsProactorEventLoopPolicy',
)
NULL = 0
INFINITE = 0xffffffff
ERROR_CONNECTION_REFUSED = 1225
ERROR_CONNECTION_ABORTED = 1236
# Initial delay in seconds for connect_pipe() before retrying to connect
CONNECT_PIPE_INIT_DELAY = 0.001
# Maximum delay in seconds for connect_pipe() before retrying to connect
CONNECT_PIPE_MAX_DELAY = 0.100
class _OverlappedFuture(futures.Future):
"""Subclass of Future which represents an overlapped operation.
Cancelling it will immediately cancel the overlapped operation.
"""
def __init__(self, ov, *, loop=None):
super().__init__(loop=loop)
if self._source_traceback:
del self._source_traceback[-1]
self._ov = ov
def _repr_info(self):
info = super()._repr_info()
if self._ov is not None:
state = 'pending' if self._ov.pending else 'completed'
info.insert(1, f'overlapped=<{state}, {self._ov.address:#x}>')
return info
def _cancel_overlapped(self):
if self._ov is None:
return
try:
self._ov.cancel()
except OSError as exc:
context = {
'message': 'Cancelling an overlapped future failed',
'exception': exc,
'future': self,
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
self._ov = None
def cancel(self, msg=None):
self._cancel_overlapped()
return super().cancel(msg=msg)
def set_exception(self, exception):
super().set_exception(exception)
self._cancel_overlapped()
def set_result(self, result):
super().set_result(result)
self._ov = None
class _BaseWaitHandleFuture(futures.Future):
"""Subclass of Future which represents a wait handle."""
def __init__(self, ov, handle, wait_handle, *, loop=None):
super().__init__(loop=loop)
if self._source_traceback:
del self._source_traceback[-1]
# Keep a reference to the Overlapped object to keep it alive until the
# wait is unregistered
self._ov = ov
self._handle = handle
self._wait_handle = wait_handle
# Should we call UnregisterWaitEx() if the wait completes
# or is cancelled?
self._registered = True
def _poll(self):
# non-blocking wait: use a timeout of 0 millisecond
return (_winapi.WaitForSingleObject(self._handle, 0) ==
_winapi.WAIT_OBJECT_0)
def _repr_info(self):
info = super()._repr_info()
info.append(f'handle={self._handle:#x}')
if self._handle is not None:
state = 'signaled' if self._poll() else 'waiting'
info.append(state)
if self._wait_handle is not None:
info.append(f'wait_handle={self._wait_handle:#x}')
return info
def _unregister_wait_cb(self, fut):
# The wait was unregistered: it's not safe to destroy the Overlapped
# object
self._ov = None
def _unregister_wait(self):
if not self._registered:
return
self._registered = False
wait_handle = self._wait_handle
self._wait_handle = None
try:
_overlapped.UnregisterWait(wait_handle)
except OSError as exc:
if exc.winerror != _overlapped.ERROR_IO_PENDING:
context = {
'message': 'Failed to unregister the wait handle',
'exception': exc,
'future': self,
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
return
# ERROR_IO_PENDING means that the unregister is pending
self._unregister_wait_cb(None)
def cancel(self, msg=None):
self._unregister_wait()
return super().cancel(msg=msg)
def set_exception(self, exception):
self._unregister_wait()
super().set_exception(exception)
def set_result(self, result):
self._unregister_wait()
super().set_result(result)
class _WaitCancelFuture(_BaseWaitHandleFuture):
"""Subclass of Future which represents a wait for the cancellation of a
_WaitHandleFuture using an event.
"""
def __init__(self, ov, event, wait_handle, *, loop=None):
super().__init__(ov, event, wait_handle, loop=loop)
self._done_callback = None
def cancel(self):
raise RuntimeError("_WaitCancelFuture must not be cancelled")
def set_result(self, result):
super().set_result(result)
if self._done_callback is not None:
self._done_callback(self)
def set_exception(self, exception):
super().set_exception(exception)
if self._done_callback is not None:
self._done_callback(self)
class _WaitHandleFuture(_BaseWaitHandleFuture):
def __init__(self, ov, handle, wait_handle, proactor, *, loop=None):
super().__init__(ov, handle, wait_handle, loop=loop)
self._proactor = proactor
self._unregister_proactor = True
self._event = _overlapped.CreateEvent(None, True, False, None)
self._event_fut = None
def _unregister_wait_cb(self, fut):
if self._event is not None:
_winapi.CloseHandle(self._event)
self._event = None
self._event_fut = None
# If the wait was cancelled, the wait may never be signalled, so
# it's required to unregister it. Otherwise, IocpProactor.close() will
# wait forever for an event which will never come.
#
# If the IocpProactor already received the event, it's safe to call
# _unregister() because we kept a reference to the Overlapped object
# which is used as a unique key.
self._proactor._unregister(self._ov)
self._proactor = None
super()._unregister_wait_cb(fut)
def _unregister_wait(self):
if not self._registered:
return
self._registered = False
wait_handle = self._wait_handle
self._wait_handle = None
try:
_overlapped.UnregisterWaitEx(wait_handle, self._event)
except OSError as exc:
if exc.winerror != _overlapped.ERROR_IO_PENDING:
context = {
'message': 'Failed to unregister the wait handle',
'exception': exc,
'future': self,
}
if self._source_traceback:
context['source_traceback'] = self._source_traceback
self._loop.call_exception_handler(context)
return
# ERROR_IO_PENDING is not an error, the wait was unregistered
self._event_fut = self._proactor._wait_cancel(self._event,
self._unregister_wait_cb)
class PipeServer(object):
"""Class representing a pipe server.
This is much like a bound, listening socket.
"""
def __init__(self, address):
self._address = address
self._free_instances = weakref.WeakSet()
# initialize the pipe attribute before calling _server_pipe_handle()
# because this function can raise an exception and the destructor calls
# the close() method
self._pipe = None
self._accept_pipe_future = None
self._pipe = self._server_pipe_handle(True)
def _get_unconnected_pipe(self):
# Create new instance and return previous one. This ensures
# that (until the server is closed) there is always at least
# one pipe handle for address. Therefore if a client attempt
# to connect it will not fail with FileNotFoundError.
tmp, self._pipe = self._pipe, self._server_pipe_handle(False)
return tmp
def _server_pipe_handle(self, first):
# Return a wrapper for a new pipe handle.
if self.closed():
return None
flags = _winapi.PIPE_ACCESS_DUPLEX | _winapi.FILE_FLAG_OVERLAPPED
if first:
flags |= _winapi.FILE_FLAG_FIRST_PIPE_INSTANCE
h = _winapi.CreateNamedPipe(
self._address, flags,
_winapi.PIPE_TYPE_MESSAGE | _winapi.PIPE_READMODE_MESSAGE |
_winapi.PIPE_WAIT,
_winapi.PIPE_UNLIMITED_INSTANCES,
windows_utils.BUFSIZE, windows_utils.BUFSIZE,
_winapi.NMPWAIT_WAIT_FOREVER, _winapi.NULL)
pipe = windows_utils.PipeHandle(h)
self._free_instances.add(pipe)
return pipe
def closed(self):
return (self._address is None)
def close(self):
if self._accept_pipe_future is not None:
self._accept_pipe_future.cancel()
self._accept_pipe_future = None
# Close all instances which have not been connected to by a client.
if self._address is not None:
for pipe in self._free_instances:
pipe.close()
self._pipe = None
self._address = None
self._free_instances.clear()
__del__ = close
class _WindowsSelectorEventLoop(selector_events.BaseSelectorEventLoop):
"""Windows version of selector event loop."""
class ProactorEventLoop(proactor_events.BaseProactorEventLoop):
"""Windows version of proactor event loop using IOCP."""
def __init__(self, proactor=None):
if proactor is None:
proactor = IocpProactor()
super().__init__(proactor)
def run_forever(self):
try:
assert self._self_reading_future is None
self.call_soon(self._loop_self_reading)
super().run_forever()
finally:
if self._self_reading_future is not None:
ov = self._self_reading_future._ov
self._self_reading_future.cancel()
# self_reading_future was just cancelled so if it hasn't been
# finished yet, it never will be (it's possible that it has
# already finished and its callback is waiting in the queue,
# where it could still happen if the event loop is restarted).
# Unregister it otherwise IocpProactor.close will wait for it
# forever
if ov is not None:
self._proactor._unregister(ov)
self._self_reading_future = None
async def create_pipe_connection(self, protocol_factory, address):
f = self._proactor.connect_pipe(address)
pipe = await f
protocol = protocol_factory()
trans = self._make_duplex_pipe_transport(pipe, protocol,
extra={'addr': address})
return trans, protocol
async def start_serving_pipe(self, protocol_factory, address):
server = PipeServer(address)
def loop_accept_pipe(f=None):
pipe = None
try:
if f:
pipe = f.result()
server._free_instances.discard(pipe)
if server.closed():
# A client connected before the server was closed:
# drop the client (close the pipe) and exit
pipe.close()
return
protocol = protocol_factory()
self._make_duplex_pipe_transport(
pipe, protocol, extra={'addr': address})
pipe = server._get_unconnected_pipe()
if pipe is None:
return
f = self._proactor.accept_pipe(pipe)
except OSError as exc:
if pipe and pipe.fileno() != -1:
self.call_exception_handler({
'message': 'Pipe accept failed',
'exception': exc,
'pipe': pipe,
})
pipe.close()
elif self._debug:
logger.warning("Accept pipe failed on pipe %r",
pipe, exc_info=True)
except exceptions.CancelledError:
if pipe:
pipe.close()
else:
server._accept_pipe_future = f
f.add_done_callback(loop_accept_pipe)
self.call_soon(loop_accept_pipe)
return [server]
async def _make_subprocess_transport(self, protocol, args, shell,
stdin, stdout, stderr, bufsize,
extra=None, **kwargs):
waiter = self.create_future()
transp = _WindowsSubprocessTransport(self, protocol, args, shell,
stdin, stdout, stderr, bufsize,
waiter=waiter, extra=extra,
**kwargs)
try:
await waiter
except (SystemExit, KeyboardInterrupt):
raise
except BaseException:
transp.close()
await transp._wait()
raise
return transp
class IocpProactor:
"""Proactor implementation using IOCP."""
def __init__(self, concurrency=0xffffffff):
self._loop = None
self._results = []
self._iocp = _overlapped.CreateIoCompletionPort(
_overlapped.INVALID_HANDLE_VALUE, NULL, 0, concurrency)
self._cache = {}
self._registered = weakref.WeakSet()
self._unregistered = []
self._stopped_serving = weakref.WeakSet()
def _check_closed(self):
if self._iocp is None:
raise RuntimeError('IocpProactor is closed')
def __repr__(self):
info = ['overlapped#=%s' % len(self._cache),
'result#=%s' % len(self._results)]
if self._iocp is None:
info.append('closed')
return '<%s %s>' % (self.__class__.__name__, " ".join(info))
def set_loop(self, loop):
self._loop = loop
def select(self, timeout=None):
if not self._results:
self._poll(timeout)
tmp = self._results
self._results = []
return tmp
def _result(self, value):
fut = self._loop.create_future()
fut.set_result(value)
return fut
def recv(self, conn, nbytes, flags=0):
self._register_with_iocp(conn)
ov = _overlapped.Overlapped(NULL)
try:
if isinstance(conn, socket.socket):
ov.WSARecv(conn.fileno(), nbytes, flags)
else:
ov.ReadFile(conn.fileno(), nbytes)
except BrokenPipeError:
return self._result(b'')
def finish_recv(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror in (_overlapped.ERROR_NETNAME_DELETED,
_overlapped.ERROR_OPERATION_ABORTED):
raise ConnectionResetError(*exc.args)
else:
raise
return self._register(ov, conn, finish_recv)
def recv_into(self, conn, buf, flags=0):
self._register_with_iocp(conn)
ov = _overlapped.Overlapped(NULL)
try:
if isinstance(conn, socket.socket):
ov.WSARecvInto(conn.fileno(), buf, flags)
else:
ov.ReadFileInto(conn.fileno(), buf)
except BrokenPipeError:
return self._result(0)
def finish_recv(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror in (_overlapped.ERROR_NETNAME_DELETED,
_overlapped.ERROR_OPERATION_ABORTED):
raise ConnectionResetError(*exc.args)
else:
raise
return self._register(ov, conn, finish_recv)
def recvfrom(self, conn, nbytes, flags=0):
self._register_with_iocp(conn)
ov = _overlapped.Overlapped(NULL)
try:
ov.WSARecvFrom(conn.fileno(), nbytes, flags)
except BrokenPipeError:
return self._result((b'', None))
def finish_recv(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror in (_overlapped.ERROR_NETNAME_DELETED,
_overlapped.ERROR_OPERATION_ABORTED):
raise ConnectionResetError(*exc.args)
else:
raise
return self._register(ov, conn, finish_recv)
def sendto(self, conn, buf, flags=0, addr=None):
self._register_with_iocp(conn)
ov = _overlapped.Overlapped(NULL)
ov.WSASendTo(conn.fileno(), buf, flags, addr)
def finish_send(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror in (_overlapped.ERROR_NETNAME_DELETED,
_overlapped.ERROR_OPERATION_ABORTED):
raise ConnectionResetError(*exc.args)
else:
raise
return self._register(ov, conn, finish_send)
def send(self, conn, buf, flags=0):
self._register_with_iocp(conn)
ov = _overlapped.Overlapped(NULL)
if isinstance(conn, socket.socket):
ov.WSASend(conn.fileno(), buf, flags)
else:
ov.WriteFile(conn.fileno(), buf)
def finish_send(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror in (_overlapped.ERROR_NETNAME_DELETED,
_overlapped.ERROR_OPERATION_ABORTED):
raise ConnectionResetError(*exc.args)
else:
raise
return self._register(ov, conn, finish_send)
def accept(self, listener):
self._register_with_iocp(listener)
conn = self._get_accept_socket(listener.family)
ov = _overlapped.Overlapped(NULL)
ov.AcceptEx(listener.fileno(), conn.fileno())
def finish_accept(trans, key, ov):
ov.getresult()
# Use SO_UPDATE_ACCEPT_CONTEXT so getsockname() etc work.
buf = struct.pack('@P', listener.fileno())
conn.setsockopt(socket.SOL_SOCKET,
_overlapped.SO_UPDATE_ACCEPT_CONTEXT, buf)
conn.settimeout(listener.gettimeout())
return conn, conn.getpeername()
async def accept_coro(future, conn):
# Coroutine closing the accept socket if the future is cancelled
try:
await future
except exceptions.CancelledError:
conn.close()
raise
future = self._register(ov, listener, finish_accept)
coro = accept_coro(future, conn)
tasks.ensure_future(coro, loop=self._loop)
return future
def connect(self, conn, address):
if conn.type == socket.SOCK_DGRAM:
# WSAConnect will complete immediately for UDP sockets so we don't
# need to register any IOCP operation
_overlapped.WSAConnect(conn.fileno(), address)
fut = self._loop.create_future()
fut.set_result(None)
return fut
self._register_with_iocp(conn)
# The socket needs to be locally bound before we call ConnectEx().
try:
_overlapped.BindLocal(conn.fileno(), conn.family)
except OSError as e:
if e.winerror != errno.WSAEINVAL:
raise
# Probably already locally bound; check using getsockname().
if conn.getsockname()[1] == 0:
raise
ov = _overlapped.Overlapped(NULL)
ov.ConnectEx(conn.fileno(), address)
def finish_connect(trans, key, ov):
ov.getresult()
# Use SO_UPDATE_CONNECT_CONTEXT so getsockname() etc work.
conn.setsockopt(socket.SOL_SOCKET,
_overlapped.SO_UPDATE_CONNECT_CONTEXT, 0)
return conn
return self._register(ov, conn, finish_connect)
def sendfile(self, sock, file, offset, count):
self._register_with_iocp(sock)
ov = _overlapped.Overlapped(NULL)
offset_low = offset & 0xffff_ffff
offset_high = (offset >> 32) & 0xffff_ffff
ov.TransmitFile(sock.fileno(),
msvcrt.get_osfhandle(file.fileno()),
offset_low, offset_high,
count, 0, 0)
def finish_sendfile(trans, key, ov):
try:
return ov.getresult()
except OSError as exc:
if exc.winerror in (_overlapped.ERROR_NETNAME_DELETED,
_overlapped.ERROR_OPERATION_ABORTED):
raise ConnectionResetError(*exc.args)
else:
raise
return self._register(ov, sock, finish_sendfile)
def accept_pipe(self, pipe):
self._register_with_iocp(pipe)
ov = _overlapped.Overlapped(NULL)
connected = ov.ConnectNamedPipe(pipe.fileno())
if connected:
# ConnectNamePipe() failed with ERROR_PIPE_CONNECTED which means
# that the pipe is connected. There is no need to wait for the
# completion of the connection.
return self._result(pipe)
def finish_accept_pipe(trans, key, ov):
ov.getresult()
return pipe
return self._register(ov, pipe, finish_accept_pipe)
async def connect_pipe(self, address):
delay = CONNECT_PIPE_INIT_DELAY
while True:
# Unfortunately there is no way to do an overlapped connect to
# a pipe. Call CreateFile() in a loop until it doesn't fail with
# ERROR_PIPE_BUSY.
try:
handle = _overlapped.ConnectPipe(address)
break
except OSError as exc:
if exc.winerror != _overlapped.ERROR_PIPE_BUSY:
raise
# ConnectPipe() failed with ERROR_PIPE_BUSY: retry later
delay = min(delay * 2, CONNECT_PIPE_MAX_DELAY)
await tasks.sleep(delay)
return windows_utils.PipeHandle(handle)
def wait_for_handle(self, handle, timeout=None):
"""Wait for a handle.
Return a Future object. The result of the future is True if the wait
completed, or False if the wait did not complete (on timeout).
"""
return self._wait_for_handle(handle, timeout, False)
def _wait_cancel(self, event, done_callback):
fut = self._wait_for_handle(event, None, True)
# add_done_callback() cannot be used because the wait may only complete
# in IocpProactor.close(), while the event loop is not running.
fut._done_callback = done_callback
return fut
def _wait_for_handle(self, handle, timeout, _is_cancel):
self._check_closed()
if timeout is None:
ms = _winapi.INFINITE
else:
# RegisterWaitForSingleObject() has a resolution of 1 millisecond,
# round away from zero to wait *at least* timeout seconds.
ms = math.ceil(timeout * 1e3)
# We only create ov so we can use ov.address as a key for the cache.
ov = _overlapped.Overlapped(NULL)
wait_handle = _overlapped.RegisterWaitWithQueue(
handle, self._iocp, ov.address, ms)
if _is_cancel:
f = _WaitCancelFuture(ov, handle, wait_handle, loop=self._loop)
else:
f = _WaitHandleFuture(ov, handle, wait_handle, self,
loop=self._loop)
if f._source_traceback:
del f._source_traceback[-1]
def finish_wait_for_handle(trans, key, ov):
# Note that this second wait means that we should only use
# this with handles types where a successful wait has no
# effect. So events or processes are all right, but locks
# or semaphores are not. Also note if the handle is
# signalled and then quickly reset, then we may return
# False even though we have not timed out.
return f._poll()
self._cache[ov.address] = (f, ov, 0, finish_wait_for_handle)
return f
def _register_with_iocp(self, obj):
# To get notifications of finished ops on this objects sent to the
# completion port, were must register the handle.
if obj not in self._registered:
self._registered.add(obj)
_overlapped.CreateIoCompletionPort(obj.fileno(), self._iocp, 0, 0)
# XXX We could also use SetFileCompletionNotificationModes()
# to avoid sending notifications to completion port of ops
# that succeed immediately.
def _register(self, ov, obj, callback):
self._check_closed()
# Return a future which will be set with the result of the
# operation when it completes. The future's value is actually
# the value returned by callback().
f = _OverlappedFuture(ov, loop=self._loop)
if f._source_traceback:
del f._source_traceback[-1]
if not ov.pending:
# The operation has completed, so no need to postpone the
# work. We cannot take this short cut if we need the
# NumberOfBytes, CompletionKey values returned by
# PostQueuedCompletionStatus().
try:
value = callback(None, None, ov)
except OSError as e:
f.set_exception(e)
else:
f.set_result(value)
# Even if GetOverlappedResult() was called, we have to wait for the
# notification of the completion in GetQueuedCompletionStatus().
# Register the overlapped operation to keep a reference to the
# OVERLAPPED object, otherwise the memory is freed and Windows may
# read uninitialized memory.
# Register the overlapped operation for later. Note that
# we only store obj to prevent it from being garbage
# collected too early.
self._cache[ov.address] = (f, ov, obj, callback)
return f
def _unregister(self, ov):
"""Unregister an overlapped object.
Call this method when its future has been cancelled. The event can
already be signalled (pending in the proactor event queue). It is also
safe if the event is never signalled (because it was cancelled).
"""
self._check_closed()
self._unregistered.append(ov)
def _get_accept_socket(self, family):
s = socket.socket(family)
s.settimeout(0)
return s
def _poll(self, timeout=None):
if timeout is None:
ms = INFINITE
elif timeout < 0:
raise ValueError("negative timeout")
else:
# GetQueuedCompletionStatus() has a resolution of 1 millisecond,
# round away from zero to wait *at least* timeout seconds.
ms = math.ceil(timeout * 1e3)
if ms >= INFINITE:
raise ValueError("timeout too big")
while True:
status = _overlapped.GetQueuedCompletionStatus(self._iocp, ms)
if status is None:
break
ms = 0
err, transferred, key, address = status
try:
f, ov, obj, callback = self._cache.pop(address)
except KeyError:
if self._loop.get_debug():
self._loop.call_exception_handler({
'message': ('GetQueuedCompletionStatus() returned an '
'unexpected event'),
'status': ('err=%s transferred=%s key=%#x address=%#x'
% (err, transferred, key, address)),
})
# key is either zero, or it is used to return a pipe
# handle which should be closed to avoid a leak.
if key not in (0, _overlapped.INVALID_HANDLE_VALUE):
_winapi.CloseHandle(key)
continue
if obj in self._stopped_serving:
f.cancel()
# Don't call the callback if _register() already read the result or
# if the overlapped has been cancelled
elif not f.done():
try:
value = callback(transferred, key, ov)
except OSError as e:
f.set_exception(e)
self._results.append(f)
else:
f.set_result(value)
self._results.append(f)
# Remove unregistered futures
for ov in self._unregistered:
self._cache.pop(ov.address, None)
self._unregistered.clear()
def _stop_serving(self, obj):
# obj is a socket or pipe handle. It will be closed in
# BaseProactorEventLoop._stop_serving() which will make any
# pending operations fail quickly.
self._stopped_serving.add(obj)
def close(self):
if self._iocp is None:
# already closed
return
# Cancel remaining registered operations.
for address, (fut, ov, obj, callback) in list(self._cache.items()):
if fut.cancelled():
# Nothing to do with cancelled futures
pass
elif isinstance(fut, _WaitCancelFuture):
# _WaitCancelFuture must not be cancelled
pass
else:
try:
fut.cancel()
except OSError as exc:
if self._loop is not None:
context = {
'message': 'Cancelling a future failed',
'exception': exc,
'future': fut,
}
if fut._source_traceback:
context['source_traceback'] = fut._source_traceback
self._loop.call_exception_handler(context)
# Wait until all cancelled overlapped complete: don't exit with running
# overlapped to prevent a crash. Display progress every second if the
# loop is still running.
msg_update = 1.0
start_time = time.monotonic()
next_msg = start_time + msg_update
while self._cache:
if next_msg <= time.monotonic():
logger.debug('%r is running after closing for %.1f seconds',
self, time.monotonic() - start_time)
next_msg = time.monotonic() + msg_update
# handle a few events, or timeout
self._poll(msg_update)
self._results = []
_winapi.CloseHandle(self._iocp)
self._iocp = None
def __del__(self):
self.close()
class _WindowsSubprocessTransport(base_subprocess.BaseSubprocessTransport):
def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
self._proc = windows_utils.Popen(
args, shell=shell, stdin=stdin, stdout=stdout, stderr=stderr,
bufsize=bufsize, **kwargs)
def callback(f):
returncode = self._proc.poll()
self._process_exited(returncode)
f = self._loop._proactor.wait_for_handle(int(self._proc._handle))
f.add_done_callback(callback)
SelectorEventLoop = _WindowsSelectorEventLoop
class WindowsSelectorEventLoopPolicy(events.BaseDefaultEventLoopPolicy):
_loop_factory = SelectorEventLoop
class WindowsProactorEventLoopPolicy(events.BaseDefaultEventLoopPolicy):
_loop_factory = ProactorEventLoop
DefaultEventLoopPolicy = WindowsProactorEventLoopPolicy

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@ -0,0 +1,173 @@
"""Various Windows specific bits and pieces."""
import sys
if sys.platform != 'win32': # pragma: no cover
raise ImportError('win32 only')
import _winapi
import itertools
import msvcrt
import os
import subprocess
import tempfile
import warnings
__all__ = 'pipe', 'Popen', 'PIPE', 'PipeHandle'
# Constants/globals
BUFSIZE = 8192
PIPE = subprocess.PIPE
STDOUT = subprocess.STDOUT
_mmap_counter = itertools.count()
# Replacement for os.pipe() using handles instead of fds
def pipe(*, duplex=False, overlapped=(True, True), bufsize=BUFSIZE):
"""Like os.pipe() but with overlapped support and using handles not fds."""
address = tempfile.mktemp(
prefix=r'\\.\pipe\python-pipe-{:d}-{:d}-'.format(
os.getpid(), next(_mmap_counter)))
if duplex:
openmode = _winapi.PIPE_ACCESS_DUPLEX
access = _winapi.GENERIC_READ | _winapi.GENERIC_WRITE
obsize, ibsize = bufsize, bufsize
else:
openmode = _winapi.PIPE_ACCESS_INBOUND
access = _winapi.GENERIC_WRITE
obsize, ibsize = 0, bufsize
openmode |= _winapi.FILE_FLAG_FIRST_PIPE_INSTANCE
if overlapped[0]:
openmode |= _winapi.FILE_FLAG_OVERLAPPED
if overlapped[1]:
flags_and_attribs = _winapi.FILE_FLAG_OVERLAPPED
else:
flags_and_attribs = 0
h1 = h2 = None
try:
h1 = _winapi.CreateNamedPipe(
address, openmode, _winapi.PIPE_WAIT,
1, obsize, ibsize, _winapi.NMPWAIT_WAIT_FOREVER, _winapi.NULL)
h2 = _winapi.CreateFile(
address, access, 0, _winapi.NULL, _winapi.OPEN_EXISTING,
flags_and_attribs, _winapi.NULL)
ov = _winapi.ConnectNamedPipe(h1, overlapped=True)
ov.GetOverlappedResult(True)
return h1, h2
except:
if h1 is not None:
_winapi.CloseHandle(h1)
if h2 is not None:
_winapi.CloseHandle(h2)
raise
# Wrapper for a pipe handle
class PipeHandle:
"""Wrapper for an overlapped pipe handle which is vaguely file-object like.
The IOCP event loop can use these instead of socket objects.
"""
def __init__(self, handle):
self._handle = handle
def __repr__(self):
if self._handle is not None:
handle = f'handle={self._handle!r}'
else:
handle = 'closed'
return f'<{self.__class__.__name__} {handle}>'
@property
def handle(self):
return self._handle
def fileno(self):
if self._handle is None:
raise ValueError("I/O operation on closed pipe")
return self._handle
def close(self, *, CloseHandle=_winapi.CloseHandle):
if self._handle is not None:
CloseHandle(self._handle)
self._handle = None
def __del__(self, _warn=warnings.warn):
if self._handle is not None:
_warn(f"unclosed {self!r}", ResourceWarning, source=self)
self.close()
def __enter__(self):
return self
def __exit__(self, t, v, tb):
self.close()
# Replacement for subprocess.Popen using overlapped pipe handles
class Popen(subprocess.Popen):
"""Replacement for subprocess.Popen using overlapped pipe handles.
The stdin, stdout, stderr are None or instances of PipeHandle.
"""
def __init__(self, args, stdin=None, stdout=None, stderr=None, **kwds):
assert not kwds.get('universal_newlines')
assert kwds.get('bufsize', 0) == 0
stdin_rfd = stdout_wfd = stderr_wfd = None
stdin_wh = stdout_rh = stderr_rh = None
if stdin == PIPE:
stdin_rh, stdin_wh = pipe(overlapped=(False, True), duplex=True)
stdin_rfd = msvcrt.open_osfhandle(stdin_rh, os.O_RDONLY)
else:
stdin_rfd = stdin
if stdout == PIPE:
stdout_rh, stdout_wh = pipe(overlapped=(True, False))
stdout_wfd = msvcrt.open_osfhandle(stdout_wh, 0)
else:
stdout_wfd = stdout
if stderr == PIPE:
stderr_rh, stderr_wh = pipe(overlapped=(True, False))
stderr_wfd = msvcrt.open_osfhandle(stderr_wh, 0)
elif stderr == STDOUT:
stderr_wfd = stdout_wfd
else:
stderr_wfd = stderr
try:
super().__init__(args, stdin=stdin_rfd, stdout=stdout_wfd,
stderr=stderr_wfd, **kwds)
except:
for h in (stdin_wh, stdout_rh, stderr_rh):
if h is not None:
_winapi.CloseHandle(h)
raise
else:
if stdin_wh is not None:
self.stdin = PipeHandle(stdin_wh)
if stdout_rh is not None:
self.stdout = PipeHandle(stdout_rh)
if stderr_rh is not None:
self.stderr = PipeHandle(stderr_rh)
finally:
if stdin == PIPE:
os.close(stdin_rfd)
if stdout == PIPE:
os.close(stdout_wfd)
if stderr == PIPE:
os.close(stderr_wfd)