first init

.venv/lib/python3.9/site-packages/smartcard/Observer.py

@@ -0,0 +1,93 @@
+"""
+from Thinking in Python, Bruce Eckel
+https://python-3-patterns-idioms-test.readthedocs.io/en/latest/Observer.html
+
+(c) Copyright 2008, Creative Commons Attribution-Share Alike 3.0.
+
+Class support for "observer" pattern.
+
+The observer class is the base class
+for all smartcard package observers.
+"""
+
+from __future__ import annotations
+
+import typing
+
+from smartcard.Synchronization import Synchronization, synchronize
+
+# pylint: disable=too-few-public-methods
+
+
+class Observer:
+    """Observer"""
+
+    def update(self, observable: Observable, handlers: typing.Any) -> None:
+        """Called when the observed object is
+        modified. You call an Observable object's
+        notifyObservers method to notify all the
+        object's observers of the change."""
+
+
+class Observable(Synchronization):
+    """Observable"""
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.obs: list[Observer] = []
+        self.changed = 0
+
+    def addObserver(self, observer: Observer) -> None:
+        """Add an observer"""
+        if observer not in self.obs:
+            self.obs.append(observer)
+
+    def deleteObserver(self, observer: Observer) -> None:
+        """Remove an observer"""
+        self.obs.remove(observer)
+
+    def notifyObservers(self, handlers: typing.Any = None) -> None:
+        """If 'changed' indicates that this object
+        has changed, notify all its observers, then
+        call clearChanged(). Each observer has its
+        update() called with two arguments: this
+        observable object and the generic 'handlers'."""
+
+        with self.mutex:
+            if not self.changed:
+                return
+            # Make a copy of the observer list.
+            observers = self.obs.copy()
+            self.changed = 0
+
+        # Update observers
+        for observer in observers:
+            observer.update(self, handlers)
+
+    def deleteObservers(self) -> None:
+        """Remove all observers"""
+        self.obs = []
+
+    def setChanged(self) -> None:
+        """Set the change flag"""
+        self.changed = 1
+
+    def clearChanged(self) -> None:
+        """Clear the change flag"""
+        self.changed = 0
+
+    def hasChanged(self) -> int:
+        """Somethig has changed?"""
+        return self.changed
+
+    def countObservers(self) -> int:
+        """Return the number of Observers"""
+        return len(self.obs)
+
+
+synchronize(
+    Observable,
+    "addObserver deleteObserver deleteObservers "
+    + "setChanged clearChanged hasChanged "
+    + "countObservers",
+)