"""
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 socket
import subprocess
import tempfile
import warnings
__all__ = ['socketpair', 'pipe', 'Popen', 'PIPE', 'PipeHandle']
# Constants/globals
BUFSIZE = 8192
PIPE = subprocess.PIPE
STDOUT = subprocess.STDOUT
_mmap_counter = itertools.count()
if hasattr(socket, 'socketpair'):
# Since Python 3.5, socket.socketpair() is now also available on Windows
socketpair = socket.socketpair
else:
# Replacement for socket.socketpair()
def socketpair(family=socket.AF_INET, type=socket.SOCK_STREAM, proto=0):
"""A socket pair usable as a self-pipe, for Windows.
Origin: https://gist.github.com/4325783, by Geert Jansen.
Public domain.
"""
if family == socket.AF_INET:
host = '127.0.0.1'
elif family == socket.AF_INET6:
host = '::1'
else:
raise ValueError("Only AF_INET and AF_INET6 socket address "
"families are supported")
if type != socket.SOCK_STREAM:
raise ValueError("Only SOCK_STREAM socket type is supported")
if proto != 0:
raise ValueError("Only protocol zero is supported")
# We create a connected TCP socket. Note the trick with setblocking(0)
# that prevents us from having to create a thread.
lsock = socket.socket(family, type, proto)
try:
lsock.bind((host, 0))
lsock.listen(1)
# On IPv6, ignore flow_info and scope_id
addr, port = lsock.getsockname()[:2]
csock = socket.socket(family, type, proto)
try:
csock.setblocking(False)
try:
csock.connect((addr, port))
except (BlockingIOError, InterruptedError):
pass
csock.setblocking(True)
ssock, _ = lsock.accept()
except:
csock.close()
raise
finally:
lsock.close()
return (ssock, csock)
# 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-' %
(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 = 'handle=%r' % self._handle
else:
handle = 'closed'
return '<%s %s>' % (self.__class__.__name__, handle)
@property
def handle(self):
return self._handle
def fileno(self):
if self._handle is None:
raise ValueError("I/O operatioon 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):
if self._handle is not None:
warnings.warn("unclosed %r" % self, 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)