| import os |
| import subprocess |
| import sys |
| |
| |
| # Backport of the Python 2.7 subprocess.CalledProcessError, including |
| # an `output` attribute. |
| class CalledProcessError(subprocess.CalledProcessError): |
| def __init__(self, returncode, cmd, output=None): |
| super(CalledProcessError, self).__init__(returncode, cmd) |
| self.output = output |
| |
| |
| # Backport of the Python 2.7 subprocess.check_output. Taken from |
| # http://hg.python.org/cpython/file/71cb8f605f77/Lib/subprocess.py |
| # Copyright (c) 2003-2005 by Peter Astrand <astrand@lysator.liu.se> |
| # Licensed to PSF under a Contributor Agreement. |
| # See http://www.python.org/2.4/license for licensing details. |
| def check_output(*popenargs, **kwargs): |
| if 'stdout' in kwargs: |
| raise ValueError('stdout argument not allowed, it will be overridden.') |
| process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs) |
| output, unused_err = process.communicate() |
| retcode = process.poll() |
| if retcode: |
| cmd = kwargs.get("args") |
| if cmd is None: |
| cmd = popenargs[0] |
| raise CalledProcessError(retcode, cmd, output=output) |
| return output |
| |
| |
| # |
| # an almost exact copy of the shutil.which() implementation from python3.4 |
| # |
| def which(cmd, mode=os.F_OK | os.X_OK, path=None): |
| """Given a command, mode, and a PATH string, return the path which |
| conforms to the given mode on the PATH, or None if there is no such |
| file. |
| |
| `mode` defaults to os.F_OK | os.X_OK. `path` defaults to the result |
| of os.environ.get("PATH"), or can be overridden with a custom search |
| path. |
| |
| """ |
| # Check that a given file can be accessed with the correct mode. |
| # Additionally check that `file` is not a directory, as on Windows |
| # directories pass the os.access check. |
| def _access_check(fn, mode): |
| return (os.path.exists(fn) and os.access(fn, mode) |
| and not os.path.isdir(fn)) |
| |
| # If we're given a path with a directory part, look it up directly rather |
| # than referring to PATH directories. This includes checking relative to |
| # the current directory, e.g. ./script |
| if os.path.dirname(cmd): |
| if _access_check(cmd, mode): |
| return cmd |
| return None |
| |
| if path is None: |
| path = os.environ.get("PATH", os.defpath) |
| if not path: |
| return None |
| path = path.split(os.pathsep) |
| |
| if sys.platform == "win32": |
| # The current directory takes precedence on Windows. |
| if os.curdir not in path: |
| path.insert(0, os.curdir) |
| |
| # PATHEXT is necessary to check on Windows. |
| pathext = os.environ.get("PATHEXT", "").split(os.pathsep) |
| # See if the given file matches any of the expected path extensions. |
| # This will allow us to short circuit when given "python.exe". |
| # If it does match, only test that one, otherwise we have to try |
| # others. |
| if any(cmd.lower().endswith(ext.lower()) for ext in pathext): |
| files = [cmd] |
| else: |
| files = [cmd + ext for ext in pathext] |
| else: |
| # On other platforms you don't have things like PATHEXT to tell you |
| # what file suffixes are executable, so just pass on cmd as-is. |
| files = [cmd] |
| |
| seen = set() |
| for dir in path: |
| normdir = os.path.normcase(dir) |
| if normdir not in seen: |
| seen.add(normdir) |
| for thefile in files: |
| name = os.path.join(dir, thefile) |
| if _access_check(name, mode): |
| return name |
| return None |