Mini Shell

# Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Copyright (C) 2013 Association of Universities for Research in Astronomy
#                    (AURA)
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#     1. Redistributions of source code must retain the above copyright
#        notice, this list of conditions and the following disclaimer.
#
#     2. Redistributions in binary form must reproduce the above
#        copyright notice, this list of conditions and the following
#        disclaimer in the documentation and/or other materials provided
#        with the distribution.
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#     3. The name of AURA and its representatives may not be used to
#        endorse or promote products derived from this software without
#        specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY AURA ``AS IS'' AND ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL AURA BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS

import contextlib
import os
import shutil
import stat
import sys

try:
    import ConfigParser as configparser
except ImportError:
    import configparser


@contextlib.contextmanager
def open_config(filename):
    if sys.version_info >= (3, 2):
        cfg = configparser.ConfigParser()
    else:
        cfg = configparser.SafeConfigParser()
    cfg.read(filename)
    yield cfg
    with open(filename, 'w') as fp:
        cfg.write(fp)


def rmtree(path):
    """shutil.rmtree() with error handler.

    Handle 'access denied' from trying to delete read-only files.
    """

    def onerror(func, path, exc_info):
        if not os.access(path, os.W_OK):
            os.chmod(path, stat.S_IWUSR)
            func(path)
        else:
            raise

    return shutil.rmtree(path, onerror=onerror)