#!/usr/bin/env python3

"""

Utilities for manging context.

"""

from . import ic # noqa: F401

class _empty_context(object):

"""

A dummy context manager.

"""

def __init__(self):

pass

def __enter__(self):

pass

def __exit__(self, *args): # noqa: U100

pass

class _state_context(object):

"""

Temporarily modify attribute(s) for an arbitrary object.

"""

def __init__(self, obj, **kwargs):

self._obj = obj

self._attrs_new = kwargs

self._attrs_prev = {

key: getattr(obj, key) for key in kwargs if hasattr(obj, key)

}

def __enter__(self):

for key, value in self._attrs_new.items():

setattr(self._obj, key, value)

def __exit__(self, *args): # noqa: U100

for key in self._attrs_new.keys():

if key in self._attrs_prev:

setattr(self._obj, key, self._attrs_prev[key])

else:

delattr(self._obj, key)