49 lines
1.3 KiB
Python
49 lines
1.3 KiB
Python
import threading
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from typing import Any
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class Singleton(type):
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"""
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A metaclass that creates a Singleton base class when called.
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"""
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_instances: dict[type, Any] = {}
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def __call__(cls, *args: Any, **kwargs: Any) -> Any:
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if cls not in cls._instances:
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instance = super().__call__(*args, **kwargs)
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cls._instances[cls] = instance
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return cls._instances[cls]
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def _reset_singleton(cls) -> None:
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"""
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Clear the singleton instance for the class.
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Useful for testing purposes.
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"""
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if cls in cls._instances:
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del cls._instances[cls]
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class ThreadSafe(type):
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"""
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A metaclass that creates a Singleton base class when called.
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"""
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_instances: dict[type, Any] = {}
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_lock = threading.Lock()
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def __call__(cls, *args: Any, **kwargs: Any) -> Any:
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with cls._lock:
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if cls not in cls._instances:
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instance = super().__call__(*args, **kwargs)
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cls._instances[cls] = instance
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return cls._instances[cls]
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def _reset_singleton(cls) -> None:
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"""
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Clear the singleton instance for the class.
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Useful for testing purposes.
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"""
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with cls._lock:
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if cls in cls._instances:
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del cls._instances[cls]
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