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Issue #23293, asyncio: Rewrite IocpProactor.connect_pipe()

Browse source 
Add _overlapped.ConnectPipe() which tries to connect to the pipe for
asynchronous I/O (overlapped): call CreateFile() in a loop until it doesn't
fail with ERROR_PIPE_BUSY. Use an increasing delay between 1 ms and 100 ms.

Remove Overlapped.WaitNamedPipeAndConnect() which is no more used.
This commit is contained in:
Victor Stinner 2015-01-22 22:55:08 +01:00
parent 752aba7f99
commit 7ffa2c5fdd
2 changed files with 48 additions and 110 deletions
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43
Lib/asyncio/windows_events.py
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@ -29,6 +29,12 @@ 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.
@ -495,25 +501,28 @@ class IocpProactor:
return self._register(ov, pipe, finish_accept_pipe,
register=False)
def connect_pipe(self, address):
ov = _overlapped.Overlapped(NULL)
ov.WaitNamedPipeAndConnect(address, self._iocp, ov.address)
def finish_connect_pipe(err, handle, ov):
# err, handle were arguments passed to PostQueuedCompletionStatus()
# in a function run in a thread pool.
if err == _overlapped.ERROR_SEM_TIMEOUT:
# Connection did not succeed within time limit.
msg = _overlapped.FormatMessage(err)
raise ConnectionRefusedError(0, msg, None, err)
elif err != 0:
msg = _overlapped.FormatMessage(err)
raise OSError(0, msg, None, err)
def _connect_pipe(self, fut, address, delay):
# 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)
except OSError as exc:
if exc.winerror == _overlapped.ERROR_PIPE_BUSY:
# Polling: retry later
delay = min(delay * 2, CONNECT_PIPE_MAX_DELAY)
self._loop.call_later(delay,
self._connect_pipe, fut, address, delay)
else:
return windows_utils.PipeHandle(handle)
fut.set_exception(exc)
else:
pipe = windows_utils.PipeHandle(handle)
fut.set_result(pipe)
return self._register(ov, None, finish_connect_pipe,
wait_for_post=True)
def connect_pipe(self, address):
fut = futures.Future(loop=self._loop)
self._connect_pipe(fut, address, CONNECT_PIPE_INIT_DELAY)
return fut
def wait_for_handle(self, handle, timeout=None):
"""Wait for a handle.