refactor backend module architecture

app/foundation/singleton.py

@@ -0,0 +1,70 @@
+import abc
+import threading
+import weakref
+
+
+class Singleton(abc.ABCMeta, type):
+    """
+    类单例模式（按参数）
+    """
+
+    _instances: dict = {}
+
+    def get_existing_instance(cls, *args, **kwargs):
+        """按相同参数返回已创建实例，不触发初始化"""
+        key = (cls, args, frozenset(kwargs.items()))
+        return cls._instances.get(key)
+
+    def __call__(cls, *args, **kwargs):
+        """按类和构造参数创建或复用实例。"""
+        key = (cls, args, frozenset(kwargs.items()))
+        if key not in cls._instances:
+            cls._instances[key] = super().__call__(*args, **kwargs)
+        return cls._instances[key]
+
+
+class AbstractSingleton(abc.ABC, metaclass=Singleton):
+    """
+    抽像类单例模式
+    """
+    pass
+
+
+class SingletonClass(abc.ABCMeta, type):
+    """
+    类单例模式（按类）
+    """
+
+    _instances: dict = {}
+
+    def get_existing_instance(cls):
+        """返回已创建实例，不触发初始化"""
+        return cls._instances.get(cls)
+
+    def __call__(cls, *args, **kwargs):
+        """按类创建或复用唯一实例。"""
+        if cls not in cls._instances:
+            cls._instances[cls] = super().__call__(*args, **kwargs)
+        return cls._instances[cls]
+
+
+class AbstractSingletonClass(abc.ABC, metaclass=SingletonClass):
+    """
+    抽像类单例模式（按类）
+    """
+    pass
+
+
+class WeakSingleton(abc.ABCMeta, type):
+    """
+    弱引用单例模式 - 当没有强引用时自动清理
+    """
+    _instances: weakref.WeakKeyDictionary = weakref.WeakKeyDictionary()
+    _lock = threading.RLock()
+
+    def __call__(cls, *args, **kwargs):
+        """按类创建或复用仍有强引用的实例。"""
+        with cls._lock:
+            if cls not in cls._instances:
+                cls._instances[cls] = super().__call__(*args, **kwargs)
+            return cls._instances[cls]