[Python] Make Cantera objects explicitly non-picklable and uncopyable.

Attempting to copy or pickle Cantera objects with an underlying C++ object
previously led to unexpected errors. These operations will not raise excptions
indicating the unimplemented feature.

Resolves Issue 205.

interfaces/cython/cantera/base.pyx

@@ -76,6 +76,12 @@ cdef class _SolutionBase:
             for i,spec in enumerate(species):
                 self._selected_species[i] = self.species_index(spec)
 
+    def __reduce__(self):
+        raise NotImplementedError('Solution object is not picklable')
+
+    def __copy__(self):
+        raise NotImplementedError('Solution object is not copyable')
+
     def __dealloc__(self):
         # only delete the C++ objects if this is the parent object
         if self.parent is None:

interfaces/cython/cantera/func1.pyx

@@ -71,3 +71,9 @@ cdef class Func1:
 
     def __call__(self, t):
         return self.func.eval(t)
+
+    def __reduce__(self):
+        raise NotImplementedError('Func1 object is not picklable')
+
+    def __copy__(self):
+        raise NotImplementedError('Func1 object is not copyable')

interfaces/cython/cantera/onedim.pyx

@@ -160,6 +160,11 @@ cdef class Domain1D:
         def __set__(self, desc):
             self.domain.setDesc(stringify(desc))
 
+    def __reduce__(self):
+        raise NotImplementedError('Domain1D object is not picklable')
+
+    def __copy__(self):
+        raise NotImplementedError('Domain1D object is not copyable')
 
 cdef class Boundary1D(Domain1D):
     """

interfaces/cython/cantera/reactor.pyx

@@ -115,6 +115,12 @@ cdef class ReactorBase:
         """
         self._walls.append(wall)
 
+    def __reduce__(self):
+        raise NotImplementedError('Reactor object is not picklable')
+
+    def __copy__(self):
+        raise NotImplementedError('Reactor object is not copyable')
+
 
 cdef class Reactor(ReactorBase):
     """
@@ -888,3 +894,9 @@ cdef class ReactorNet:
         """
         def __get__(self):
             return self.net.neq()
+
+    def __reduce__(self):
+        raise NotImplementedError('ReactorNet object is not picklable')
+
+    def __copy__(self):
+        raise NotImplementedError('ReactorNet object is not copyable')

interfaces/cython/cantera/test/test_func1.py

@@ -39,3 +39,15 @@ class TestFunc1(utilities.CanteraTest):
 
         f = ct.Func1(fails)
         self.assertRaises(ValueError, f, 0.1)
+
+    def test_unpicklable(self):
+        import pickle
+        f = ct.Func1(np.sin)
+        with self.assertRaises(NotImplementedError):
+            pickle.dumps(f)
+
+    def test_uncopyable(self):
+        import copy
+        f = ct.Func1(np.sin)
+        with self.assertRaises(NotImplementedError):
+            copy.copy(f)

interfaces/cython/cantera/test/test_onedim.py

@@ -47,6 +47,20 @@ class TestOnedim(utilities.CanteraTest):
         self.assertArrayNear(inlet.X, Xref)
         self.assertArrayNear(inlet.Y, Yref)
 
+    def test_unpicklable(self):
+        import pickle
+        gas = ct.Solution('h2o2.xml')
+        flame = ct.FreeFlow(gas)
+        with self.assertRaises(NotImplementedError):
+            pickle.dumps(flame)
+
+    def test_uncopyable(self):
+        import copy
+        gas = ct.Solution('h2o2.xml')
+        flame = ct.FreeFlow(gas)
+        with self.assertRaises(NotImplementedError):
+            copy.copy(flame)
+
 
 class TestFreeFlame(utilities.CanteraTest):
     tol_ss = [1.0e-5, 1.0e-14]  # [rtol atol] for steady-state problem

interfaces/cython/cantera/test/test_reactor.py

@@ -474,6 +474,23 @@ class TestReactor(utilities.CanteraTest):
         self.assertNear(p1a, p1b)
         self.assertNear(p2a, p2b)
 
+    def test_unpicklable(self):
+        self.make_reactors()
+        import pickle
+        with self.assertRaises(NotImplementedError):
+            pickle.dumps(self.r1)
+        with self.assertRaises(NotImplementedError):
+            pickle.dumps(self.net)
+
+    def test_uncopyable(self):
+        self.make_reactors()
+        import copy
+        with self.assertRaises(NotImplementedError):
+            copy.copy(self.r1)
+        with self.assertRaises(NotImplementedError):
+            copy.copy(self.net)
+
+
 class TestIdealGasReactor(TestReactor):
     reactorClass = ct.IdealGasReactor
 

interfaces/cython/cantera/test/test_thermo.py

@@ -307,6 +307,16 @@ class TestThermoPhase(utilities.CanteraTest):
         self.assertNear(self.phase.min_temp, 300.0)
         self.assertNear(self.phase.max_temp, 3500.0)
 
+    def test_unpicklable(self):
+        import pickle
+        with self.assertRaises(NotImplementedError):
+            pickle.dumps(self.phase)
+
+    def test_uncopyable(self):
+        import copy
+        with self.assertRaises(NotImplementedError):
+            copy.copy(self.phase)
+
 
 class TestThermo(utilities.CanteraTest):
     def setUp(self):