| # Copyright (c) cocotb contributors | |
| # All rights reserved. | |
| # | |
| # Redistribution and use in source and binary forms, with or without | |
| # modification, are permitted provided that the following conditions are met: | |
| # * Redistributions of source code must retain the above copyright | |
| # notice, this list of conditions and the following disclaimer. | |
| # * 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. | |
| # * Neither the name of the copyright holder nor the | |
| # names of its contributors may be used to endorse or promote products | |
| # derived from this software without specific prior written permission. | |
| # | |
| # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 POTENTIAL VENTURES LTD BE LIABLE FOR ANY | |
| # DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
| # (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND | |
| # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
| # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| """ | |
| Backports and compatibility shims for newer python features. | |
| These are for internal use - users should use a third party library like `six` | |
| if they want to use these shims in their own code | |
| """ | |
| import sys | |
| # backport of Python 3.7's contextlib.nullcontext | |
| class nullcontext: | |
| """Context manager that does no additional processing. | |
| Used as a stand-in for a normal context manager, when a particular | |
| block of code is only sometimes used with a normal context manager: | |
| cm = optional_cm if condition else nullcontext() | |
| with cm: | |
| # Perform operation, using optional_cm if condition is True | |
| """ | |
| def __init__(self, enter_result=None): | |
| self.enter_result = enter_result | |
| def __enter__(self): | |
| return self.enter_result | |
| def __exit__(self, *excinfo): | |
| pass | |
| # On python 3.7 onwards, `dict` is guaranteed to preserve insertion order. | |
| # Since `OrderedDict` is a little slower that `dict`, we prefer the latter | |
| # when possible. | |
| if sys.version_info[:2] >= (3, 7): # noqa: UP036 | bug in ruff | |
| insertion_ordered_dict = dict | |
| else: | |
| import collections | |
| insertion_ordered_dict = collections.OrderedDict | |
| # simple, but less than optimal backport of Python 3.8's cached_property | |
| if sys.version_info >= (3, 8): | |
| from functools import cached_property | |
| else: | |
| from functools import lru_cache | |
| def cached_property(meth): | |
| return property(lru_cache(maxsize=None)(meth)) | |