🚫🥒 do not pickle the unpickleable RWLock (#199)

* 🚫🥒 do not pickle the unpickleable RWLock

* As requested, acquired the lock before copying PointJacobi. When failing to acquire the lock, it now returns None. Think that's fine or prefer something else?

Added `__ne__` for CurveFp.

I think `test_inaquality_points_diff_types` from test_ellipticcurve.py was not actually testing equality. Because there was no `__ne__`, it was falling back to identity comparison, causing the test to pass. Now that there's a `__ne__`, it was getting NotImplemented which surprisingly bool casts to True. I changed the `__eq__` to return False for different types.

Fix typo in `test_inaquality_points_diff_types` name.

As requested, ran black on modified files. It reformmated some lines I hadn't modified.

* ran black with `--line-length 79` as configured in travis-ci for the project

* Revert to returning NotImplemented.
For __ne__ use == instead of __eq__ so it handles NotImplemented when the types are different.
Remove the not needed state declaration.

Author: adhintz

src/ecdsa/ellipticcurve.py

@@ -101,6 +101,9 @@ def __eq__(self, other):
             )
         return NotImplemented
 
+    def __ne__(self, other):
+        return not (self == other)
+
     def __hash__(self):
         return hash((self.__p, self.__a, self.__b))
 
@@ -185,6 +188,19 @@ def __init__(self, curve, x, y, z, order=None, generator=False):
                 doubler = doubler.double().scale()
                 self.__precompute.append((doubler.x(), doubler.y()))
 
+    def __getstate__(self):
+        try:
+            self._scale_lock.reader_acquire()
+            state = self.__dict__.copy()
+        finally:
+            self._scale_lock.reader_release()
+        del state["_scale_lock"]
+        return state
+
+    def __setstate__(self, state):
+        self.__dict__.update(state)
+        self._scale_lock = RWLock()
+
     def __eq__(self, other):
         """Compare two points with each-other."""
         try:

src/ecdsa/test_ellipticcurve.py

@@ -195,6 +195,6 @@ def test_inequality_points(self):
         p = Point(c, 100, 100, 100)
         self.assertNotEqual(self.g_23, p)
 
-    def test_inaquality_points_diff_types(self):
+    def test_inequality_points_diff_types(self):
         c = CurveFp(100, -3, 100)
         self.assertNotEqual(self.g_23, c)

src/ecdsa/test_jacobi.py

@@ -1,3 +1,5 @@
+import pickle
+
 try:
     import unittest2 as unittest
 except ImportError:
@@ -6,7 +8,7 @@
 import hypothesis.strategies as st
 from hypothesis import given, assume, settings, example
 
-from .ellipticcurve import Point, PointJacobi, INFINITY
+from .ellipticcurve import CurveFp, Point, PointJacobi, INFINITY
 from .ecdsa import generator_256, curve_256, generator_224
 from .numbertheory import inverse_mod
 
@@ -384,3 +386,12 @@ def test_mul_add_large(self):
         self.assertEqual(
             j_g * (0xFF00 + 255 * 0xF0F0), j_g.mul_add(0xFF00, b, 0xF0F0)
         )
+
+    def test_equality(self):
+        pj1 = PointJacobi(curve=CurveFp(23, 1, 1, 1), x=2, y=3, z=1, order=1)
+        pj2 = PointJacobi(curve=CurveFp(23, 1, 1, 1), x=2, y=3, z=1, order=1)
+        self.assertEqual(pj1, pj2)
+
+    def test_pickle(self):
+        pj = PointJacobi(curve=CurveFp(23, 1, 1, 1), x=2, y=3, z=1, order=1)
+        self.assertEqual(pickle.loads(pickle.dumps(pj)), pj)