Fix various reference-counting bugs found by gcc-cpychecker

Author: mdboom

src/constants.c

@@ -48,6 +48,7 @@ Py_Constant_cnew(ftpy_ConstantType *type, unsigned long value)
     }
     self = (PyLong_Type.tp_new)((PyTypeObject *)type, args, NULL);
     if (self == NULL) {
+        Py_DECREF(args);
         return NULL;
     }
     Py_DECREF(args);
@@ -252,7 +253,6 @@ static int make_constant_type(
 
     if (PyType_Ready(py_constant_type) < 0)
         return -1;
-    Py_INCREF(py_constant_type);
 
     return 0;
 }
@@ -285,7 +285,6 @@ static int make_bitflag_type(
 
     if (PyType_Ready(py_constant_type) < 0)
         return -1;
-    Py_INCREF(py_constant_type);
 
     return 0;
 }

src/file.c

@@ -153,6 +153,8 @@ PyObject* ftpy_PyFile_OpenFile(PyObject *filename, const char *mode)
     open = PyDict_GetItemString(builtins, "open");
     if (open == NULL) {
         Py_DECREF(builtins);
+        PyErr_SetString(PyExc_AttributeError,
+                        "Internal error: could not get open function");
         return NULL;
     }
     Py_DECREF(builtins);

src/pyutil.c

@@ -133,7 +133,11 @@ int ftpy_setup_type(PyObject *module, PyTypeObject *type)
         return 0;
     } else {
         name = qualified_name_to_name(type->tp_name);
-        return PyModule_AddObject(module, name, (PyObject *)type);
+        if (PyModule_AddObject(module, name, (PyObject *)type)) {
+            Py_DECREF(type);
+            return -1;
+        }
+        return 0;
     }
 }
 
@@ -193,6 +197,7 @@ PyObject *ftpy_PyBuffer_ToList(PyObject *obj)
     list[2] = NULL;
 
     if (PyObject_GetBuffer(obj, &view, 0)) {
+        PyErr_SetString(PyExc_TypeError, "Could not get buffer");
         return NULL;
     }