mirror of
https://github.com/jxxghp/MoviePilot.git
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95 lines
3.1 KiB
Python
95 lines
3.1 KiB
Python
import abc
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import threading
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import weakref
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class Singleton(abc.ABCMeta, type):
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"""
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类单例模式（按参数）
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"""
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_instances: dict = {}
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_lock = threading.RLock()
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def get_existing_instance(cls, *args, **kwargs):
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"""按相同参数返回已创建实例，不触发初始化"""
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key = (cls, args, frozenset(kwargs.items()))
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with cls._lock:
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return cls._instances.get(key)
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def __call__(cls, *args, **kwargs):
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"""按类和构造参数创建或复用实例。"""
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key = (cls, args, frozenset(kwargs.items()))
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with cls._lock:
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if key not in cls._instances:
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if getattr(cls, "_retain_failed_singleton", False):
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# 启动线程的 lifecycle owner 必须先发布身份再执行 __init__；
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# 构造中途抛错时保留实例，启动失败清理才能找到已创建的 owner。
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instance = cls.__new__(cls, *args, **kwargs)
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if not isinstance(instance, cls):
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return instance
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cls._instances[key] = instance
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cls.__init__(instance, *args, **kwargs)
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else:
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cls._instances[key] = super().__call__(*args, **kwargs)
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return cls._instances[key]
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class AbstractSingleton(abc.ABC, metaclass=Singleton):
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"""
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抽像类单例模式
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"""
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pass
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class SingletonClass(abc.ABCMeta, type):
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"""
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类单例模式（按类）
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"""
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_instances: dict = {}
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_lock = threading.RLock()
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def get_existing_instance(cls):
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"""返回已创建实例，不触发初始化"""
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with cls._lock:
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return cls._instances.get(cls)
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def __call__(cls, *args, **kwargs):
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"""按类创建或复用唯一实例。"""
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with cls._lock:
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if cls not in cls._instances:
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if getattr(cls, "_retain_failed_singleton", False):
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# 与参数化单例保持相同的 owner 发布顺序；锁会阻止其他线程
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# 在 __init__ 返回或抛错前读取半构造实例。
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instance = cls.__new__(cls, *args, **kwargs)
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if not isinstance(instance, cls):
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return instance
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cls._instances[cls] = instance
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cls.__init__(instance, *args, **kwargs)
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else:
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cls._instances[cls] = super().__call__(*args, **kwargs)
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return cls._instances[cls]
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class AbstractSingletonClass(abc.ABC, metaclass=SingletonClass):
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"""
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抽像类单例模式（按类）
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"""
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pass
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class WeakSingleton(abc.ABCMeta, type):
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"""
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弱引用单例模式 - 当没有强引用时自动清理
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"""
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_instances: weakref.WeakKeyDictionary = weakref.WeakKeyDictionary()
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_lock = threading.RLock()
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def __call__(cls, *args, **kwargs):
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"""按类创建或复用仍有强引用的实例。"""
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with cls._lock:
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if cls not in cls._instances:
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cls._instances[cls] = super().__call__(*args, **kwargs)
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return cls._instances[cls]
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