1 files changed, 75 insertions, 0 deletions
diff --git a/libmproxy/stateobject.py b/libmproxy/stateobject.py
new file mode 100644
index 00000000..ef8879b8
--- /dev/null
+++ b/libmproxy/stateobject.py
@@ -0,0 +1,75 @@
+class StateObject:
+    def _get_state(self):
+        raise NotImplementedError
+
+    def _load_state(self, state):
+        raise NotImplementedError
+
+    @classmethod
+    def _from_state(cls, state):
+        raise NotImplementedError
+
+    def __eq__(self, other):
+        try:
+            return self._get_state() == other._get_state()
+        except AttributeError:  # we may compare with something that's not a StateObject
+            return False
+
+
+class SimpleStateObject(StateObject):
+    """
+    A StateObject with opionated conventions that tries to keep everything DRY.
+
+    Simply put, you agree on a list of attributes and their type.
+    Attributes can either be primitive types(str, tuple, bool, ...) or StateObject instances themselves.
+    SimpleStateObject uses this information for the default _get_state(), _from_state(s) and _load_state(s) methods.
+    Overriding _get_state or _load_state to add custom adjustments is always possible.
+    """
+
+    _stateobject_attributes = None  # none by default to raise an exception if definition was forgotten
+    """
+    An attribute-name -> class-or-type dict containing all attributes that should be serialized
+    If the attribute is a class, this class must be a subclass of StateObject.
+    """
+
+    def _get_state(self):
+        return {attr: self._get_state_attr(attr, cls)
+                for attr, cls in self._stateobject_attributes.iteritems()}
+
+    def _get_state_attr(self, attr, cls):
+        """
+        helper for _get_state.
+        returns the value of the given attribute
+        """
+        val = getattr(self, attr)
+        if hasattr(val, "_get_state"):
+            return val._get_state()
+        else:
+            return val
+
+    def _load_state(self, state):
+        for attr, cls in self._stateobject_attributes.iteritems():
+            self._load_state_attr(attr, cls, state)
+
+    def _load_state_attr(self, attr, cls, state):
+        """
+        helper for _load_state.
+        loads the given attribute from the state.
+        """
+        if state[attr] is None:
+            setattr(self, attr, None)
+            return
+
+        curr = getattr(self, attr)
+        if hasattr(curr, "_load_state"):
+            curr._load_state(state[attr])
+        elif hasattr(cls, "_from_state"):
+            setattr(self, attr, cls._from_state(state[attr]))
+        else:
+            setattr(self, attr, cls(state[attr]))
+
+    @classmethod
+    def _from_state(cls, state):
+        f = cls()  # the default implementation assumes an empty constructor. Override accordingly.
+        f._load_state(state)
+        return f
+\ No newline at end of file