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pyfec: import a copy of fileutil.py from the pyutil library
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186
pyfec/fec/util/fileutil.py
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186
pyfec/fec/util/fileutil.py
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# Copyright (c) 2000 Autonomous Zone Industries
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# Copyright (c) 2002-2007 Bryce "Zooko" Wilcox-O'Hearn
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# This file is licensed under the
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# GNU Lesser General Public License v2.1.
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# See the file COPYING or visit http://www.gnu.org/ for details.
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# Portions snarfed out of the Python standard library.
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# The du part is due to Jim McCoy.
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"""
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Futz with files like a pro.
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"""
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import exceptions, os, stat, tempfile, time
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try:
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from twisted.python import log
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except ImportError:
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class DummyLog:
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def msg(self, *args, **kwargs):
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pass
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log = DummyLog()
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def rename(src, dst, tries=4, basedelay=0.1):
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""" Here is a superkludge to workaround the fact that occasionally on
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Windows some other process (e.g. an anti-virus scanner, a local search
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engine, etc.) is looking at your file when you want to delete or move it,
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and hence you can't. The horrible workaround is to sit and spin, trying
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to delete it, for a short time and then give up.
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With the default values of tries and basedelay this can block for less
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than a second.
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@param tries: number of tries -- each time after the first we wait twice
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as long as the previous wait
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@param basedelay: how long to wait before the second try
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"""
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for i in range(tries-1):
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try:
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return os.rename(src, dst)
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except EnvironmentError, le:
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# XXX Tighten this to check if this is a permission denied error (possibly due to another Windows process having the file open and execute the superkludge only in this case.
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log.msg("XXX KLUDGE Attempting to move file %s => %s; got %s; sleeping %s seconds" % (src, dst, le, basedelay,))
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time.sleep(basedelay)
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basedelay *= 2
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return os.rename(src, dst) # The last try.
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def remove(f, tries=4, basedelay=0.1):
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""" Here is a superkludge to workaround the fact that occasionally on
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Windows some other process (e.g. an anti-virus scanner, a local search
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engine, etc.) is looking at your file when you want to delete or move it,
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and hence you can't. The horrible workaround is to sit and spin, trying
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to delete it, for a short time and then give up.
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With the default values of tries and basedelay this can block for less
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than a second.
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@param tries: number of tries -- each time after the first we wait twice
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as long as the previous wait
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@param basedelay: how long to wait before the second try
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"""
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try:
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os.chmod(f, stat.S_IWRITE | stat.S_IEXEC | stat.S_IREAD)
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except:
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pass
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for i in range(tries-1):
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try:
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return os.remove(f)
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except EnvironmentError, le:
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# XXX Tighten this to check if this is a permission denied error (possibly due to another Windows process having the file open and execute the superkludge only in this case.
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if not os.path.exists(f):
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return
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log.msg("XXX KLUDGE Attempting to remove file %s; got %s; sleeping %s seconds" % (f, le, basedelay,))
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time.sleep(basedelay)
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basedelay *= 2
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return os.remove(f) # The last try.
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class NamedTemporaryDirectory:
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"""
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This calls tempfile.mkdtemp(), stores the name of the dir in
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self.name, and rmrf's the dir when it gets garbage collected or
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"shutdown()".
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"""
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def __init__(self, cleanup=True, *args, **kwargs):
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""" If cleanup, then the directory will be rmrf'ed when the object is shutdown. """
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self.cleanup = cleanup
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self.name = tempfile.mkdtemp(*args, **kwargs)
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def __repr__(self):
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return "<%s instance at %x %s>" % (self.__class__.__name__, id(self), self.name)
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def __str__(self):
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return self.__repr__()
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def __del__(self):
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try:
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self.shutdown()
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except:
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import traceback
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traceback.print_exc()
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def shutdown(self):
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if self.cleanup and hasattr(self, 'name'):
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rm_dir(self.name)
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def make_dirs(dirname, mode=0777, strictmode=False):
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"""
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A threadsafe and idempotent version of os.makedirs(). If the dir already
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exists, do nothing and return without raising an exception. If this call
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creates the dir, return without raising an exception. If there is an
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error that prevents creation or if the directory gets deleted after
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make_dirs() creates it and before make_dirs() checks that it exists, raise
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an exception.
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@param strictmode if true, then make_dirs() will raise an exception if the
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directory doesn't have the desired mode. For example, if the
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directory already exists, and has a different mode than the one
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specified by the mode parameter, then if strictmode is true,
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make_dirs() will raise an exception, else it will ignore the
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discrepancy.
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"""
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tx = None
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try:
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os.makedirs(dirname, mode)
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except OSError, x:
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tx = x
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if not os.path.isdir(dirname):
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if tx:
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raise tx
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raise exceptions.IOError, "unknown error prevented creation of directory, or deleted the directory immediately after creation: %s" % dirname # careful not to construct an IOError with a 2-tuple, as that has a special meaning...
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tx = None
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if hasattr(os, 'chmod'):
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try:
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os.chmod(dirname, mode)
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except OSError, x:
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tx = x
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if strictmode and hasattr(os, 'stat'):
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s = os.stat(dirname)
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resmode = stat.S_IMODE(s.st_mode)
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if resmode != mode:
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if tx:
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raise tx
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raise exceptions.IOError, "unknown error prevented setting correct mode of directory, or changed mode of the directory immediately after creation. dirname: %s, mode: %04o, resmode: %04o" % (dirname, mode, resmode,) # careful not to construct an IOError with a 2-tuple, as that has a special meaning...
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def rm_dir(dirname):
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"""
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A threadsafe and idempotent version of shutil.rmtree(). If the dir is
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already gone, do nothing and return without raising an exception. If this
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call removes the dir, return without raising an exception. If there is an
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error that prevents deletion or if the directory gets created again after
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rm_dir() deletes it and before rm_dir() checks that it is gone, raise an
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exception.
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"""
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excs = []
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try:
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os.chmod(dirname, stat.S_IWRITE | stat.S_IEXEC | stat.S_IREAD)
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for f in os.listdir(dirname):
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fullname = os.path.join(dirname, f)
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if os.path.isdir(fullname):
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rm_dir(fullname)
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else:
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remove(fullname)
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os.rmdir(dirname)
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except Exception, le:
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# Ignore "No such file or directory"
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if (not isinstance(le, OSError)) or le.args[0] != 2:
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excs.append(le)
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# Okay, now we've recursively removed everything, ignoring any "No
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# such file or directory" errors, and collecting any other errors.
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if os.path.exists(dirname):
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if len(excs) == 1:
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raise excs[0]
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if len(excs) == 0:
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raise OSError, "Failed to remove dir for unknown reason."
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raise OSError, excs
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def remove_if_possible(f):
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try:
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remove(f)
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except:
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pass
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