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ensure a fallback exists, so use local std{in,out,err}...
ensure a fallback exists, so use local std{in,out,err} Since IOStream instances require a valid fallback stream, use the locally defined std{in,out,err} instead of sys.std{in,out,err} in IOTerm's __init__ method. Note that the local std{in,out,err} are IOStream instances as well, that fall back to os.devnull

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"""Windows-specific implementation of process utilities.
This file is only meant to be imported by process.py, not by end-users.
# Copyright (C) 2010-2011 The IPython Development Team
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
# Imports
from __future__ import print_function
# stdlib
import os
import sys
import ctypes
import msvcrt
from ctypes import c_int, POINTER
from ctypes.wintypes import LPCWSTR, HLOCAL
from subprocess import STDOUT
# our own imports
from ._process_common import read_no_interrupt, process_handler, arg_split as py_arg_split
from . import py3compat
from . import text
# Function definitions
class AvoidUNCPath(object):
"""A context manager to protect command execution from UNC paths.
In the Win32 API, commands can't be invoked with the cwd being a UNC path.
This context manager temporarily changes directory to the 'C:' drive on
entering, and restores the original working directory on exit.
The context manager returns the starting working directory *if* it made a
change and None otherwise, so that users can apply the necessary adjustment
to their system calls in the event of a change.
cmd = 'dir'
with AvoidUNCPath() as path:
if path is not None:
cmd = '"pushd %s &&"%s' % (path, cmd)
def __enter__(self):
self.path = os.getcwdu()
self.is_unc_path = self.path.startswith(r"\\")
if self.is_unc_path:
# change to c drive (as cmd.exe cannot handle UNC addresses)
return self.path
# We return None to signal that there was no change in the working
# directory
return None
def __exit__(self, exc_type, exc_value, traceback):
if self.is_unc_path:
def _find_cmd(cmd):
"""Find the full path to a .bat or .exe using the win32api module."""
from win32api import SearchPath
except ImportError:
raise ImportError('you need to have pywin32 installed for this to work')
PATH = os.environ['PATH']
extensions = ['.exe', '.com', '.bat', '.py']
path = None
for ext in extensions:
path = SearchPath(PATH, cmd + ext)[0]
if path is None:
raise OSError("command %r not found" % cmd)
return path
def _system_body(p):
"""Callback for _system."""
enc = text.getdefaultencoding()
for line in read_no_interrupt(p.stdout).splitlines():
line = line.decode(enc, 'replace')
print(line, file=sys.stdout)
for line in read_no_interrupt(p.stderr).splitlines():
line = line.decode(enc, 'replace')
print(line, file=sys.stderr)
# Wait to finish for returncode
return p.wait()
def system(cmd):
"""Win32 version of os.system() that works with network shares.
Note that this implementation returns None, as meant for use in IPython.
cmd : str
A command to be executed in the system shell.
None : we explicitly do NOT return the subprocess status code, as this
utility is meant to be used extensively in IPython, where any return value
would trigger :func:`sys.displayhook` calls.
# The controller provides interactivity with both
# stdin and stdout
import _process_win32_controller
def getoutput(cmd):
"""Return standard output of executing cmd in a shell.
Accepts the same arguments as os.system().
cmd : str
A command to be executed in the system shell.
stdout : str
with AvoidUNCPath() as path:
if path is not None:
cmd = '"pushd %s &&"%s' % (path, cmd)
out = process_handler(cmd, lambda p: p.communicate()[0], STDOUT)
if out is None:
out = ''
return out
CommandLineToArgvW = ctypes.windll.shell32.CommandLineToArgvW
CommandLineToArgvW.arg_types = [LPCWSTR, POINTER(c_int)]
CommandLineToArgvW.res_types = [POINTER(LPCWSTR)]
LocalFree = ctypes.windll.kernel32.LocalFree
LocalFree.res_type = HLOCAL
LocalFree.arg_types = [HLOCAL]
def arg_split(commandline, posix=False, strict=True):
"""Split a command line's arguments in a shell-like manner.
This is a special version for windows that use a ctypes call to CommandLineToArgvW
to do the argv splitting. The posix paramter is ignored.
If strict=False, process_common.arg_split(...strict=False) is used instead.
#CommandLineToArgvW returns path to executable if called with empty string.
if commandline.strip() == "":
return []
if not strict:
# not really a cl-arg, fallback on _process_common
return py_arg_split(commandline, posix=posix, strict=strict)
argvn = c_int()
result_pointer = CommandLineToArgvW(py3compat.cast_unicode(commandline.lstrip()), ctypes.byref(argvn))
result_array_type = LPCWSTR * argvn.value
result = [arg for arg in result_array_type.from_address(result_pointer)]
retval = LocalFree(result_pointer)
return result
except AttributeError:
arg_split = py_arg_split