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# IVLE - Informatics Virtual Learning Environment
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# Copyright (C) 2007-2008 The University of Melbourne
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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# Contains common utility functions.
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class IVLEError(Exception):
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"""Legacy general IVLE exception.
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This is the old "standard" exception class for IVLE errors. It is only
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used in fileservice, and should not be used in any new code.
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def __init__(self, httpcode, message=None):
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self.httpcode = httpcode
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self.message = message
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self.args = (httpcode, message)
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class IVLEJailError(Exception):
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"""Exception proxying an in-jail error.
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This exception indicates an error that occurred inside an IVLE CGI script
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inside the jail. It should never be raised directly - only by the
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Information will be retrieved from it, and then treated as a normal
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def __init__(self, type_str, message, info):
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self.type_str = type_str
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self.message = message
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class FakeObject(object):
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""" A representation of an object that can't be Pickled """
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def __init__(self, type, name, attrib={}):
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return "<Fake %s %s>"%(self.type, self.name)
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"""Given a path, returns a tuple consisting of the top-level directory in
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the path, and the rest of the path. Note that both items in the tuple will
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NOT begin with a slash, regardless of whether the original path did. Also
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Always returns a pair of strings, except for one special case, in which
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the path is completely empty (or just a single slash). In this case the
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return value will be (None, ''). But still always returns a pair.
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>>> split_path("home")
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>>> split_path("home/docs/files")
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('home', 'docs/files')
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>>> split_path("//home/docs/files")
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('', 'home/docs/files')
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path = os.path.normpath(path)
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# Ignore the opening slash
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if path.startswith(os.sep):
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path = path[len(os.sep):]
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if path == '' or path == '.':
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splitpath = path.split(os.sep, 1)
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if len(splitpath) == 1:
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return (splitpath[0], '')
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return tuple(splitpath)
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def relpath(path, start=os.path.curdir):
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"""Return a relative version of a path.
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XXX Backported from Python 2.6 posixpath.py.
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raise ValueError("no path specified")
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start_list = os.path.abspath(start).split(os.path.sep)
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path_list = os.path.abspath(path).split(os.path.sep)
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# Work out how much of the filepath is shared by start and path.
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i = len(os.path.commonprefix([start_list, path_list]))
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rel_list = [os.path.pardir] * (len(start_list)-i) + path_list[i:]
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return os.path.curdir
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return os.path.join(*rel_list)
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def incomplete_utf8_sequence(byteseq):
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"""Calculate the completeness of a UTF-8 encoded string.
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Given a UTF-8-encoded byte sequence (str), returns the number of bytes at
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the end of the string which comprise an incomplete UTF-8 character
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If the string is empty or ends with a complete character OR INVALID
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Otherwise, returns 1-3 indicating the number of bytes in the final
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incomplete (but valid) character sequence.
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Does not check any bytes before the final sequence for correctness.
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>>> incomplete_utf8_sequence("")
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>>> incomplete_utf8_sequence("xy")
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>>> incomplete_utf8_sequence("xy\xc3\xbc")
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>>> incomplete_utf8_sequence("\xc3")
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>>> incomplete_utf8_sequence("\xbc\xc3")
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>>> incomplete_utf8_sequence("xy\xbc\xc3")
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>>> incomplete_utf8_sequence("xy\xe0\xa0")
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>>> incomplete_utf8_sequence("xy\xf4")
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>>> incomplete_utf8_sequence("xy\xf4\x8f")
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>>> incomplete_utf8_sequence("xy\xf4\x8f\xa0")
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for b in byteseq[::-1]:
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# 0xxxxxxx (single-byte character)
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elif b & 0xc0 == 0x80:
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# 10xxxxxx (subsequent byte)
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elif b & 0xe0 == 0xc0:
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# 110xxxxx (start of 2-byte sequence)
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elif b & 0xf0 == 0xe0:
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# 1110xxxx (start of 3-byte sequence)
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elif b & 0xf8 == 0xf0:
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# 11110xxx (start of 4-byte sequence)
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# Seen too many "subsequent bytes", invalid
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# We never saw a "first byte", invalid
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# We now know expect and count
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# Complete, or we saw an invalid sequence
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def object_to_dict(attrnames, obj):
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"""Convert an object into a dictionary.
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This takes a shallow copy of the object.
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@param attrnames: Set (or iterable) of names of attributes to be copied
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into the dictionary. (We don't auto-lookup, because this
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function needs to be used on magical objects).
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return dict((k, getattr(obj, k))
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for k in attrnames if not k.startswith('_'))
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def safe_rmtree(path, ignore_errors=False, onerror=None):
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"""Recursively delete a directory tree.
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Copied from shutil.rmtree from Python 2.6, which does not follow symbolic
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links (it is otherwise unsafe to call as root on untrusted directories; do
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not use shutil.rmtree in this case, as you may be running Python 2.5).
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If ignore_errors is set, errors are ignored; otherwise, if onerror
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is set, it is called to handle the error with arguments (func,
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path, exc_info) where func is os.listdir, os.remove, or os.rmdir;
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path is the argument to that function that caused it to fail; and
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exc_info is a tuple returned by sys.exc_info(). If ignore_errors
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is false and onerror is None, an exception is raised.
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elif onerror is None:
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if os.path.islink(path):
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# symlinks to directories are forbidden, see bug #1669
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raise OSError("Cannot call safe_rmtree on a symbolic link")
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onerror(os.path.islink, path, sys.exc_info())
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# can't continue even if onerror hook returns
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names = os.listdir(path)
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except os.error, err:
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onerror(os.listdir, path, sys.exc_info())
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fullname = os.path.join(path, name)
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mode = os.lstat(fullname).st_mode
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if stat.S_ISDIR(mode):
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safe_rmtree(fullname, ignore_errors, onerror)
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except os.error, err:
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onerror(os.remove, fullname, sys.exc_info())
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onerror(os.rmdir, path, sys.exc_info())
added
removed
ivle/util.py
