32 lines
856 B
Python
32 lines
856 B
Python
import threading
|
|
from typing import Any
|
|
|
|
|
|
class Singleton(type):
|
|
"""
|
|
A metaclass that creates a Singleton base class when called.
|
|
"""
|
|
|
|
_instances: dict[type, Any] = {}
|
|
|
|
def __call__(cls, *args: Any, **kwargs: Any) -> Any:
|
|
if cls not in cls._instances:
|
|
instance = super().__call__(*args, **kwargs)
|
|
cls._instances[cls] = instance
|
|
return cls._instances[cls]
|
|
|
|
|
|
class ThreadSafe(type):
|
|
"""
|
|
A metaclass that creates a Singleton base class when called.
|
|
"""
|
|
|
|
_instances: dict[type, Any] = {}
|
|
_lock = threading.Lock()
|
|
|
|
def __call__(cls, *args: Any, **kwargs: Any) -> Any:
|
|
with cls._lock:
|
|
if cls not in cls._instances:
|
|
instance = super().__call__(*args, **kwargs)
|
|
cls._instances[cls] = instance
|
|
return cls._instances[cls]
|