| from contextlib import contextmanager |
| |
| from pip._vendor.contextlib2 import ExitStack |
| |
| from pip._internal.utils.typing import MYPY_CHECK_RUNNING |
| |
| if MYPY_CHECK_RUNNING: |
| from typing import Iterator, ContextManager, TypeVar |
| |
| _T = TypeVar('_T', covariant=True) |
| |
| |
| class CommandContextMixIn(object): |
| def __init__(self): |
| # type: () -> None |
| super(CommandContextMixIn, self).__init__() |
| self._in_main_context = False |
| self._main_context = ExitStack() |
| |
| @contextmanager |
| def main_context(self): |
| # type: () -> Iterator[None] |
| assert not self._in_main_context |
| |
| self._in_main_context = True |
| try: |
| with self._main_context: |
| yield |
| finally: |
| self._in_main_context = False |
| |
| def enter_context(self, context_provider): |
| # type: (ContextManager[_T]) -> _T |
| assert self._in_main_context |
| |
| return self._main_context.enter_context(context_provider) |