53 lines
1.4 KiB
Python
53 lines
1.4 KiB
Python
import threading
|
|
from typing import Any
|
|
|
|
|
|
class Singleton(type):
|
|
"""
|
|
A metaclass that creates a Singleton base class when called.
|
|
"""
|
|
|
|
_instances: dict[type, Any] = {}
|
|
"The singleton instances."
|
|
|
|
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]
|
|
|
|
def _reset_singleton(cls) -> None:
|
|
"""
|
|
Clear the singleton instance for the class.
|
|
Useful for testing purposes.
|
|
"""
|
|
if cls in cls._instances:
|
|
del cls._instances[cls]
|
|
|
|
|
|
class ThreadSafe(type):
|
|
"""
|
|
A metaclass that creates a Singleton base class when called.
|
|
"""
|
|
|
|
_instances: dict[type, Any] = {}
|
|
"The singleton instances."
|
|
|
|
_lock = threading.Lock()
|
|
"A lock to ensure thread-safe singleton creation."
|
|
|
|
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]
|
|
|
|
def _reset_singleton(cls) -> None:
|
|
"""
|
|
Clear the singleton instance for the class.
|
|
Useful for testing purposes.
|
|
"""
|
|
with cls._lock:
|
|
if cls in cls._instances:
|
|
del cls._instances[cls]
|