# -*- coding: latin-1 -*-
#!/usr/bin/env python
# PySys System Test Framework, Copyright (C) 2006-2020 M.B. Grieve
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""
File and directory handling utility functions such as mkdir and deletedir, with enhanced error handling and
support for long paths on Windows.
"""
import os, shutil, time, locale
from pysys.constants import IS_WINDOWS
from pysys.utils.pycompat import PY2
[docs]def toLongPathSafe(path, onlyIfNeeded=False):
"""
Converts the specified path string to a form suitable for passing to API
calls if it exceeds the maximum path length on this OS.
Currently, this is necessary only on Windows, where a unicode string
starting with \\?\ must be used to get correct behaviour for long paths.
On Windows this function also normalizes the capitalization of drive
letters so they are always upper case regardless of OS version and current
working directory.
:param path: A path. Must not be a relative path. Can be None/empty. Can
contain ".." sequences. If possible, use a unicode character string.
On Python 2, byte strings are permitted and converted using
``locale.getpreferredencoding()``.
:param onlyIfNeeded: Set to True to only adds the long path support if this
path exceeds the maximum length on this OS (e.g. 256 chars). You must keep
this at False if you will be adding extra characters on to the end of the
returned string.
:return: The passed-in path, possibly with a ``\\?\`` prefix added,
forward slashes converted to backslashes on Windows, and converted to
a unicode string. Trailing slashes may be removed.
Note that the conversion to unicode requires a lot of care on Python 2
where byte strings are more common, since it is not possible to combine
unicode and byte strings (if they have non-ascii characters), for example
for a log statement.
"""
if (not IS_WINDOWS) or (not path): return path
if path[0] != path[0].upper(): path = path[0].upper()+path[1:]
if onlyIfNeeded and len(path)<255: return path
if path.startswith('\\\\?\\'): return path
inputpath = path
# ".." is not permitted in \\?\ paths; normpath is expensive so don't do this unless we have to
if '.' in path:
path = os.path.normpath(path)
else:
# path is most likely to contain / so more efficient to conditionalize this
path = path.replace('/','\\')
if '\\\\' in path:
# consecutive \ separators are not permitted in \\?\ paths
path = path.replace('\\\\','\\')
if PY2 and isinstance(path, str):
path = path.decode(locale.getpreferredencoding())
if path.startswith(u'\\\\'):
path = u'\\\\?\\UNC\\'+path.lstrip('\\') # \\?\UNC\server\share
else:
path = u'\\\\?\\'+path
return path
[docs]def fromLongPathSafe(path):
"""
Strip off ``\\?\`` prefixes added by L{toLongPathSafe}.
Note that this function does not convert unicode strings back to byte
strings, so if you want a complete reversal of toLongPathSafe you will
additionally have to call C{result.encode(locale.getpreferredencoding())}.
"""
if not path: return path
if not path.startswith('\\\\?\\'): return path
if path.startswith('\\\\?\\UNC\\'):
result = '\\'+path[7:]
else:
result = path[4:]
return result
[docs]def pathexists(path):
""" Returns True if the specified path is an existing file or directory,
as returned by C{os.path.exists}.
This method is safe to call on paths that may be over the Windows 256
character limit.
:param path: If None or empty, returns True. Only Python 2, can be a
unicode or byte string.
"""
return path and os.path.exists(toLongPathSafe(path))
[docs]def mkdir(path):
"""
Create a directory, with recursive creation of any parent directories.
This function is a no-op (does not throw) if the directory already exists.
:return: Returns the path passed in.
"""
origpath = path
path = toLongPathSafe(path, onlyIfNeeded=True)
try:
os.makedirs(path)
except Exception as e:
if not os.path.isdir(path):
# occasionally fails on windows for no reason, so add retry
time.sleep(0.1)
os.makedirs(path)
return origpath
[docs]def deletedir(path, retries=1, ignore_errors=False, onerror=None):
"""
Recursively delete the specified directory, with optional retries.
Does nothing if it does not exist. Raises an exception if the deletion fails (unless ``onerror=`` is specified),
but deletes as many files as possible before doing so.
:param retries: The number of retries to attempt. This can be useful to
work around temporary failures causes by Windows file locking.
:param ignore_errors: If True, an exception is raised if the path exists but cannot be deleted.
:param onerror: A callable that with arguments (function, path, excinfo), called when an error occurs while
deleting. See the documentation for ``shutil.rmtree`` for more information.
"""
if ignore_errors: assert onerror==None, 'cannot set onerror and also ignore_errors'
path = toLongPathSafe(path)
try:
# delete as many files as we can first, so if there's an error deleting some files (e.g. due to windows file
# locking) we don't use any more disk space than we need to
shutil.rmtree(path, ignore_errors=True)
# then try again, being more careful
if os.path.exists(path) and not ignore_errors:
shutil.rmtree(path, onerror=onerror)
except Exception: # pragma: no cover
if not os.path.exists(path): return # nothing to do
if retries <= 0:
raise
time.sleep(0.5) # work around windows file-locking issues
deletedir(path, retries = retries-1, onerror=onerror)