Spaces:
Running
Running
File size: 2,173 Bytes
f5f3483 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 |
# Copyright 2024 The etils Authors.
#
# 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.
"""Contextmanager utils."""
from __future__ import annotations
import abc
import contextlib
from typing import Generic, Iterable, TypeVar
_T = TypeVar('_T')
# TODO(epot): Support
# * Per-instance (done)
# * Inheritance with `super()`
# * Multi-thread
# * Covariable
# * Re-entry
# * Immutable classes
class ContextManager(abc.ABC, Generic[_T]):
"""ContextManager allows to define contextmanager class using yield-syntax.
Example:
```python
class A(epy.ContextManager):
def __contextmanager__(self) -> Iterable[A]:
yield self
with A() as a:
pass
```
One the code is more mature, this could be merged to `contextlib` directly.
https://discuss.python.org/t/yield-based-contextmanager-for-classes/8453
"""
def __init_subclass__(cls, **kwargs):
super().__init_subclass__(**kwargs)
# Check whether the class is already wrapped in a CM
if not hasattr(cls.__contextmanager__, '_cm_added'):
cls.__contextmanager__ = contextlib.contextmanager(cls.__contextmanager__)
cls.__contextmanager__._cm_added = (
True # pylint: disable=protected-access
)
@abc.abstractmethod
def __contextmanager__(self) -> Iterable[_T]:
pass
__contextmanager__._cm_added = True # pylint: disable=protected-access
def __enter__(self) -> _T:
self._epy_cm = self.__contextmanager__()
return self._epy_cm.__enter__() # pytype: disable=attribute-error
def __exit__(self, exc_type, exc_value, traceback) -> None:
return self._epy_cm.__exit__(exc_type, exc_value, traceback) # pytype: disable=attribute-error
|