diff options
Diffstat (limited to '.venv/lib/python3.12/site-packages/openpyxl/compat/singleton.py')
-rw-r--r-- | .venv/lib/python3.12/site-packages/openpyxl/compat/singleton.py | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/openpyxl/compat/singleton.py b/.venv/lib/python3.12/site-packages/openpyxl/compat/singleton.py new file mode 100644 index 00000000..1fe6a908 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/openpyxl/compat/singleton.py @@ -0,0 +1,40 @@ +# Copyright (c) 2010-2024 openpyxl + +import weakref + + +class Singleton(type): + """ + Singleton metaclass + Based on Python Cookbook 3rd Edition Recipe 9.13 + Only one instance of a class can exist. Does not work with __slots__ + """ + + def __init__(self, *args, **kw): + super().__init__(*args, **kw) + self.__instance = None + + def __call__(self, *args, **kw): + if self.__instance is None: + self.__instance = super().__call__(*args, **kw) + return self.__instance + + +class Cached(type): + """ + Caching metaclass + Child classes will only create new instances of themselves if + one doesn't already exist. Does not work with __slots__ + """ + + def __init__(self, *args, **kw): + super().__init__(*args, **kw) + self.__cache = weakref.WeakValueDictionary() + + def __call__(self, *args): + if args in self.__cache: + return self.__cache[args] + + obj = super().__call__(*args) + self.__cache[args] = obj + return obj |