Source code for mmengine.registry.default_scope
# Copyright (c) OpenMMLab. All rights reserved.
import copy
import time
from contextlib import contextmanager
from typing import Generator, Optional
from mmengine.utils.manager import ManagerMixin, _accquire_lock, _release_lock
[docs]class DefaultScope(ManagerMixin):
"""Scope of current task used to reset the current registry, which can be
accessed globally.
Consider the case of resetting the current ``Registry`` by
``default_scope`` in the internal module which cannot access runner
directly, it is difficult to get the ``default_scope`` defined in
``Runner``. However, if ``Runner`` created ``DefaultScope`` instance
by given ``default_scope``, the internal module can get
``default_scope`` by ``DefaultScope.get_current_instance`` everywhere.
Args:
name (str): Name of default scope for global access.
scope_name (str): Scope of current task.
Examples:
>>> from mmengine.model import MODELS
>>> # Define default scope in runner.
>>> DefaultScope.get_instance('task', scope_name='mmdet')
>>> # Get default scope globally.
>>> scope_name = DefaultScope.get_instance('task').scope_name
"""
def __init__(self, name: str, scope_name: str):
super().__init__(name)
assert isinstance(
scope_name,
str), (f'scope_name should be a string, but got {scope_name}')
self._scope_name = scope_name
@property
def scope_name(self) -> str:
"""
Returns:
str: Get current scope.
"""
return self._scope_name
[docs] @classmethod
def get_current_instance(cls) -> Optional['DefaultScope']:
"""Get latest created default scope.
Since default_scope is an optional argument for ``Registry.build``.
``get_current_instance`` should return ``None`` if there is no
``DefaultScope`` created.
Examples:
>>> default_scope = DefaultScope.get_current_instance()
>>> # There is no `DefaultScope` created yet,
>>> # `get_current_instance` return `None`.
>>> default_scope = DefaultScope.get_instance(
>>> 'instance_name', scope_name='mmengine')
>>> default_scope.scope_name
mmengine
>>> default_scope = DefaultScope.get_current_instance()
>>> default_scope.scope_name
mmengine
Returns:
Optional[DefaultScope]: Return None If there has not been
``DefaultScope`` instance created yet, otherwise return the
latest created DefaultScope instance.
"""
_accquire_lock()
if cls._instance_dict:
instance = super().get_current_instance()
else:
instance = None
_release_lock()
return instance
[docs] @classmethod
@contextmanager
def overwrite_default_scope(cls, scope_name: Optional[str]) -> Generator:
"""Overwrite the current default scope with `scope_name`"""
if scope_name is None:
yield
else:
tmp = copy.deepcopy(cls._instance_dict)
# To avoid create an instance with the same name.
time.sleep(1e-6)
cls.get_instance(f'overwrite-{time.time()}', scope_name=scope_name)
try:
yield
finally:
cls._instance_dict = tmp