third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/python/google/protobuf/pyext/message.cc

Index: third_party/protobuf/python/google/protobuf/pyext/message.cc
diff --git a/third_party/protobuf/python/google/protobuf/pyext/message.cc b/third_party/protobuf/python/google/protobuf/pyext/message.cc
index 83c151ff626aabab287e8bfe39b4b8b80e99791f..4f3abc84bedce3584629ef4d98d52792e3dcbdaa 100644
--- a/third_party/protobuf/python/google/protobuf/pyext/message.cc
+++ b/third_party/protobuf/python/google/protobuf/pyext/message.cc
@@ -63,11 +63,12 @@
 #include <google/protobuf/pyext/repeated_composite_container.h>
 #include <google/protobuf/pyext/repeated_scalar_container.h>
 #include <google/protobuf/pyext/map_container.h>
+#include <google/protobuf/pyext/message_factory.h>
+#include <google/protobuf/pyext/safe_numerics.h>
 #include <google/protobuf/pyext/scoped_pyobject_ptr.h>
 #include <google/protobuf/stubs/strutil.h>
 
 #if PY_MAJOR_VERSION >= 3
-  #define PyInt_Check PyLong_Check
   #define PyInt_AsLong PyLong_AsLong
   #define PyInt_FromLong PyLong_FromLong
   #define PyInt_FromSize_t PyLong_FromSize_t
@@ -91,8 +92,6 @@ namespace protobuf {
 namespace python {
 
 static PyObject* kDESCRIPTOR;
-static PyObject* k_extensions_by_name;
-static PyObject* k_extensions_by_number;
 PyObject* EnumTypeWrapper_class;
 static PyObject* PythonMessage_class;
 static PyObject* kEmptyWeakref;
@@ -127,19 +126,6 @@ static bool AddFieldNumberToClass(
 
 // Finalize the creation of the Message class.
 static int AddDescriptors(PyObject* cls, const Descriptor* descriptor) {
-  // If there are extension_ranges, the message is "extendable", and extension
-  // classes will register themselves in this class.
-  if (descriptor->extension_range_count() > 0) {
-    ScopedPyObjectPtr by_name(PyDict_New());
-    if (PyObject_SetAttr(cls, k_extensions_by_name, by_name.get()) < 0) {
-      return -1;
-    }
-    ScopedPyObjectPtr by_number(PyDict_New());
-    if (PyObject_SetAttr(cls, k_extensions_by_number, by_number.get()) < 0) {
-      return -1;
-    }
-  }
-
   // For each field set: cls.<field>_FIELD_NUMBER = <number>
   for (int i = 0; i < descriptor->field_count(); ++i) {
     if (!AddFieldNumberToClass(cls, descriptor->field(i))) {
@@ -244,6 +230,12 @@ static PyObject* New(PyTypeObject* type,
     return NULL;
   }
 
+  // Messages have no __dict__
+  ScopedPyObjectPtr slots(PyTuple_New(0));
+  if (PyDict_SetItemString(dict, "__slots__", slots.get()) < 0) {
+    return NULL;
+  }
+
   // Build the arguments to the base metaclass.
   // We change the __bases__ classes.
   ScopedPyObjectPtr new_args;
@@ -300,16 +292,19 @@ static PyObject* New(PyTypeObject* type,
   newtype->message_descriptor = descriptor;
   // TODO(amauryfa): Don't always use the canonical pool of the descriptor,
   // use the MessageFactory optionally passed in the class dict.
-  newtype->py_descriptor_pool = GetDescriptorPool_FromPool(
-      descriptor->file()->pool());
-  if (newtype->py_descriptor_pool == NULL) {
+  PyDescriptorPool* py_descriptor_pool =
+      GetDescriptorPool_FromPool(descriptor->file()->pool());
+  if (py_descriptor_pool == NULL) {
     return NULL;
   }
-  Py_INCREF(newtype->py_descriptor_pool);
+  newtype->py_message_factory = py_descriptor_pool->py_message_factory;
+  Py_INCREF(newtype->py_message_factory);
 
-  // Add the message to the DescriptorPool.
-  if (cdescriptor_pool::RegisterMessageClass(newtype->py_descriptor_pool,
-                                             descriptor, newtype) < 0) {
+  // Register the message in the MessageFactory.
+  // TODO(amauryfa): Move this call to MessageFactory.GetPrototype() when the
+  // MessageFactory is fully implemented in C++.
+  if (message_factory::RegisterMessageClass(newtype->py_message_factory,
+                                            descriptor, newtype) < 0) {
     return NULL;
   }
 
@@ -321,8 +316,8 @@ static PyObject* New(PyTypeObject* type,
 }
 
 static void Dealloc(CMessageClass *self) {
-  Py_DECREF(self->py_message_descriptor);
-  Py_DECREF(self->py_descriptor_pool);
+  Py_XDECREF(self->py_message_descriptor);
+  Py_XDECREF(self->py_message_factory);
   Py_TYPE(self)->tp_free(reinterpret_cast<PyObject*>(self));
 }
 
@@ -347,6 +342,61 @@ static int InsertEmptyWeakref(PyTypeObject *base_type) {
 #endif  // PY_MAJOR_VERSION >= 3
 }
 
+// The _extensions_by_name dictionary is built on every access.
+// TODO(amauryfa): Migrate all users to pool.FindAllExtensions()
+static PyObject* GetExtensionsByName(CMessageClass *self, void *closure) {
+  const PyDescriptorPool* pool = self->py_message_factory->pool;
+
+  std::vector<const FieldDescriptor*> extensions;
+  pool->pool->FindAllExtensions(self->message_descriptor, &extensions);
+
+  ScopedPyObjectPtr result(PyDict_New());
+  for (int i = 0; i < extensions.size(); i++) {
+    ScopedPyObjectPtr extension(
+        PyFieldDescriptor_FromDescriptor(extensions[i]));
+    if (extension == NULL) {
+      return NULL;
+    }
+    if (PyDict_SetItemString(result.get(), extensions[i]->full_name().c_str(),
+                             extension.get()) < 0) {
+      return NULL;
+    }
+  }
+  return result.release();
+}
+
+// The _extensions_by_number dictionary is built on every access.
+// TODO(amauryfa): Migrate all users to pool.FindExtensionByNumber()
+static PyObject* GetExtensionsByNumber(CMessageClass *self, void *closure) {
+  const PyDescriptorPool* pool = self->py_message_factory->pool;
+
+  std::vector<const FieldDescriptor*> extensions;
+  pool->pool->FindAllExtensions(self->message_descriptor, &extensions);
+
+  ScopedPyObjectPtr result(PyDict_New());
+  for (int i = 0; i < extensions.size(); i++) {
+    ScopedPyObjectPtr extension(
+        PyFieldDescriptor_FromDescriptor(extensions[i]));
+    if (extension == NULL) {
+      return NULL;
+    }
+    ScopedPyObjectPtr number(PyInt_FromLong(extensions[i]->number()));
+    if (number == NULL) {
+      return NULL;
+    }
+    if (PyDict_SetItem(result.get(), number.get(), extension.get()) < 0) {
+      return NULL;
+    }
+  }
+  return result.release();
+}
+
+static PyGetSetDef Getters[] = {
+  {"_extensions_by_name", (getter)GetExtensionsByName, NULL},
+  {"_extensions_by_number", (getter)GetExtensionsByNumber, NULL},
+  {NULL}
+};
+
 }  // namespace message_meta
 
 PyTypeObject CMessageClass_Type = {
@@ -379,7 +429,7 @@ PyTypeObject CMessageClass_Type = {
   0,                                   // tp_iternext
   0,                                   // tp_methods
   0,                                   // tp_members
-  0,                                   // tp_getset
+  message_meta::Getters,               // tp_getset
   0,                                   // tp_base
   0,                                   // tp_dict
   0,                                   // tp_descr_get
@@ -515,23 +565,10 @@ int ForEachCompositeField(CMessage* self, Visitor visitor) {
 
 // ---------------------------------------------------------------------
 
-// Constants used for integer type range checking.
-PyObject* kPythonZero;
-PyObject* kint32min_py;
-PyObject* kint32max_py;
-PyObject* kuint32max_py;
-PyObject* kint64min_py;
-PyObject* kint64max_py;
-PyObject* kuint64max_py;
-
 PyObject* EncodeError_class;
 PyObject* DecodeError_class;
 PyObject* PickleError_class;
 
-// Constant PyString values used for GetAttr/GetItem.
-static PyObject* k_cdescriptor;
-static PyObject* kfull_name;
-
 /* Is 64bit */
 void FormatTypeError(PyObject* arg, char* expected_types) {
   PyObject* repr = PyObject_Repr(arg);
@@ -545,68 +582,126 @@ void FormatTypeError(PyObject* arg, char* expected_types) {
   }
 }
 
-template<class T>
-bool CheckAndGetInteger(
-    PyObject* arg, T* value, PyObject* min, PyObject* max) {
-  bool is_long = PyLong_Check(arg);
-#if PY_MAJOR_VERSION < 3
-  if (!PyInt_Check(arg) && !is_long) {
-    FormatTypeError(arg, "int, long");
-    return false;
+void OutOfRangeError(PyObject* arg) {
+  PyObject *s = PyObject_Str(arg);
+  if (s) {
+    PyErr_Format(PyExc_ValueError,
+                 "Value out of range: %s",
+                 PyString_AsString(s));
+    Py_DECREF(s);
   }
-  if (PyObject_Compare(min, arg) > 0 || PyObject_Compare(max, arg) < 0) {
-#else
-  if (!is_long) {
-    FormatTypeError(arg, "int");
+}
+
+template<class RangeType, class ValueType>
+bool VerifyIntegerCastAndRange(PyObject* arg, ValueType value) {
+  if GOOGLE_PREDICT_FALSE(value == -1 && PyErr_Occurred()) {
+    if (PyErr_ExceptionMatches(PyExc_OverflowError)) {
+      // Replace it with the same ValueError as pure python protos instead of
+      // the default one.
+      PyErr_Clear();
+      OutOfRangeError(arg);
+    }  // Otherwise propagate existing error.
     return false;
   }
-  if (PyObject_RichCompareBool(min, arg, Py_LE) != 1 ||
-      PyObject_RichCompareBool(max, arg, Py_GE) != 1) {
-#endif
-    if (!PyErr_Occurred()) {
-      PyObject *s = PyObject_Str(arg);
-      if (s) {
-        PyErr_Format(PyExc_ValueError,
-                     "Value out of range: %s",
-                     PyString_AsString(s));
-        Py_DECREF(s);
-      }
-    }
+  if GOOGLE_PREDICT_FALSE(!IsValidNumericCast<RangeType>(value)) {
+    OutOfRangeError(arg);
     return false;
   }
+  return true;
+}
+
+template<class T>
+bool CheckAndGetInteger(PyObject* arg, T* value) {
+  // The fast path.
 #if PY_MAJOR_VERSION < 3
-  if (!is_long) {
-    *value = static_cast<T>(PyInt_AsLong(arg));
-  } else  // NOLINT
+  // For the typical case, offer a fast path.
+  if GOOGLE_PREDICT_TRUE(PyInt_Check(arg)) {
+    long int_result =  PyInt_AsLong(arg);
+    if GOOGLE_PREDICT_TRUE(IsValidNumericCast<T>(int_result)) {
+      *value = static_cast<T>(int_result);
+      return true;
+    } else {
+      OutOfRangeError(arg);
+      return false;
+    }
+  }
 #endif
-  {
-    if (min == kPythonZero) {
-      *value = static_cast<T>(PyLong_AsUnsignedLongLong(arg));
+  // This effectively defines an integer as "an object that can be cast as
+  // an integer and can be used as an ordinal number".
+  // This definition includes everything that implements numbers.Integral
+  // and shouldn't cast the net too wide.
+  if GOOGLE_PREDICT_FALSE(!PyIndex_Check(arg)) {
+    FormatTypeError(arg, "int, long");
+    return false;
+  }
+
+  // Now we have an integral number so we can safely use PyLong_ functions.
+  // We need to treat the signed and unsigned cases differently in case arg is
+  // holding a value above the maximum for signed longs.
+  if (std::numeric_limits<T>::min() == 0) {
+    // Unsigned case.
+    unsigned PY_LONG_LONG ulong_result;
+    if (PyLong_Check(arg)) {
+      ulong_result = PyLong_AsUnsignedLongLong(arg);
     } else {
-      *value = static_cast<T>(PyLong_AsLongLong(arg));
+      // Unlike PyLong_AsLongLong, PyLong_AsUnsignedLongLong is very
+      // picky about the exact type.
+      PyObject* casted = PyNumber_Long(arg);
+      if GOOGLE_PREDICT_FALSE(casted == NULL) {
+        // Propagate existing error.
+        return false;
+      }
+      ulong_result = PyLong_AsUnsignedLongLong(casted);
+      Py_DECREF(casted);
+    }
+    if (VerifyIntegerCastAndRange<T, unsigned PY_LONG_LONG>(arg,
+                                                            ulong_result)) {
+      *value = static_cast<T>(ulong_result);
+    } else {
+      return false;
+    }
+  } else {
+    // Signed case.
+    PY_LONG_LONG long_result;
+    PyNumberMethods *nb;
+    if ((nb = arg->ob_type->tp_as_number) != NULL && nb->nb_int != NULL) {
+      // PyLong_AsLongLong requires it to be a long or to have an __int__()
+      // method.
+      long_result = PyLong_AsLongLong(arg);
+    } else {
+      // Valid subclasses of numbers.Integral should have a __long__() method
+      // so fall back to that.
+      PyObject* casted = PyNumber_Long(arg);
+      if GOOGLE_PREDICT_FALSE(casted == NULL) {
+        // Propagate existing error.
+        return false;
+      }
+      long_result = PyLong_AsLongLong(casted);
+      Py_DECREF(casted);
+    }
+    if (VerifyIntegerCastAndRange<T, PY_LONG_LONG>(arg, long_result)) {
+      *value = static_cast<T>(long_result);
+    } else {
+      return false;
     }
   }
+
   return true;
 }
 
 // These are referenced by repeated_scalar_container, and must
 // be explicitly instantiated.
-template bool CheckAndGetInteger<int32>(
-    PyObject*, int32*, PyObject*, PyObject*);
-template bool CheckAndGetInteger<int64>(
-    PyObject*, int64*, PyObject*, PyObject*);
-template bool CheckAndGetInteger<uint32>(
-    PyObject*, uint32*, PyObject*, PyObject*);
-template bool CheckAndGetInteger<uint64>(
-    PyObject*, uint64*, PyObject*, PyObject*);
+template bool CheckAndGetInteger<int32>(PyObject*, int32*);
+template bool CheckAndGetInteger<int64>(PyObject*, int64*);
+template bool CheckAndGetInteger<uint32>(PyObject*, uint32*);
+template bool CheckAndGetInteger<uint64>(PyObject*, uint64*);
 
 bool CheckAndGetDouble(PyObject* arg, double* value) {
-  if (!PyInt_Check(arg) && !PyLong_Check(arg) &&
-      !PyFloat_Check(arg)) {
+  *value = PyFloat_AsDouble(arg);
+  if GOOGLE_PREDICT_FALSE(*value == -1 && PyErr_Occurred()) {
     FormatTypeError(arg, "int, long, float");
     return false;
   }
-  *value = PyFloat_AsDouble(arg);
   return true;
 }
 
@@ -620,11 +715,13 @@ bool CheckAndGetFloat(PyObject* arg, float* value) {
 }
 
 bool CheckAndGetBool(PyObject* arg, bool* value) {
-  if (!PyInt_Check(arg) && !PyBool_Check(arg) && !PyLong_Check(arg)) {
+  long long_value = PyInt_AsLong(arg);
+  if (long_value == -1 && PyErr_Occurred()) {
     FormatTypeError(arg, "int, long, bool");
     return false;
   }
-  *value = static_cast<bool>(PyInt_AsLong(arg));
+  *value = static_cast<bool>(long_value);
+
   return true;
 }
 
@@ -752,15 +849,9 @@ bool CheckFieldBelongsToMessage(const FieldDescriptor* field_descriptor,
 
 namespace cmessage {
 
-PyDescriptorPool* GetDescriptorPoolForMessage(CMessage* message) {
-  // No need to check the type: the type of instances of CMessage is always
-  // an instance of CMessageClass. Let's prove it with a debug-only check.
+PyMessageFactory* GetFactoryForMessage(CMessage* message) {
   GOOGLE_DCHECK(PyObject_TypeCheck(message, &CMessage_Type));
-  return reinterpret_cast<CMessageClass*>(Py_TYPE(message))->py_descriptor_pool;
-}
-
-MessageFactory* GetFactoryForMessage(CMessage* message) {
-  return GetDescriptorPoolForMessage(message)->message_factory;
+  return reinterpret_cast<CMessageClass*>(Py_TYPE(message))->py_message_factory;
 }
 
 static int MaybeReleaseOverlappingOneofField(
@@ -813,7 +904,8 @@ static Message* GetMutableMessage(
     return NULL;
   }
   return reflection->MutableMessage(
-      parent_message, parent_field, GetFactoryForMessage(parent));
+      parent_message, parent_field,
+      GetFactoryForMessage(parent)->message_factory);
 }
 
 struct FixupMessageReference : public ChildVisitor {
@@ -961,20 +1053,7 @@ int InternalDeleteRepeatedField(
   int min, max;
   length = reflection->FieldSize(*message, field_descriptor);
 
-  if (PyInt_Check(slice) || PyLong_Check(slice)) {
-    from = to = PyLong_AsLong(slice);
-    if (from < 0) {
-      from = to = length + from;
-    }
-    step = 1;
-    min = max = from;
-
-    // Range check.
-    if (from < 0 || from >= length) {
-      PyErr_Format(PyExc_IndexError, "list assignment index out of range");
-      return -1;
-    }
-  } else if (PySlice_Check(slice)) {
+  if (PySlice_Check(slice)) {
     from = to = step = slice_length = 0;
     PySlice_GetIndicesEx(
 #if PY_MAJOR_VERSION < 3
@@ -991,8 +1070,23 @@ int InternalDeleteRepeatedField(
       max = from;
     }
   } else {
-    PyErr_SetString(PyExc_TypeError, "list indices must be integers");
-    return -1;
+    from = to = PyLong_AsLong(slice);
+    if (from == -1 && PyErr_Occurred()) {
+      PyErr_SetString(PyExc_TypeError, "list indices must be integers");
+      return -1;
+    }
+
+    if (from < 0) {
+      from = to = length + from;
+    }
+    step = 1;
+    min = max = from;
+
+    // Range check.
+    if (from < 0 || from >= length) {
+      PyErr_Format(PyExc_IndexError, "list assignment index out of range");
+      return -1;
+    }
   }
 
   Py_ssize_t i = from;
@@ -1041,7 +1135,12 @@ int InternalDeleteRepeatedField(
 }
 
 // Initializes fields of a message. Used in constructors.
-int InitAttributes(CMessage* self, PyObject* kwargs) {
+int InitAttributes(CMessage* self, PyObject* args, PyObject* kwargs) {
+  if (args != NULL && PyTuple_Size(args) != 0) {
+    PyErr_SetString(PyExc_TypeError, "No positional arguments allowed");
+    return -1;
+  }
+
   if (kwargs == NULL) {
     return 0;
   }
@@ -1167,7 +1266,9 @@ int InitAttributes(CMessage* self, PyObject* kwargs) {
       }
       CMessage* cmessage = reinterpret_cast<CMessage*>(message.get());
       if (PyDict_Check(value)) {
-        if (InitAttributes(cmessage, value) < 0) {
+        // Make the message exist even if the dict is empty.
+        AssureWritable(cmessage);
+        if (InitAttributes(cmessage, NULL, value) < 0) {
           return -1;
         }
       } else {
@@ -1226,7 +1327,7 @@ static PyObject* New(PyTypeObject* cls,
   if (message_descriptor == NULL) {
     return NULL;
   }
-  const Message* default_message = type->py_descriptor_pool->message_factory
+  const Message* default_message = type->py_message_factory->message_factory
                                    ->GetPrototype(message_descriptor);
   if (default_message == NULL) {
     PyErr_SetString(PyExc_TypeError, message_descriptor->full_name().c_str());
@@ -1245,12 +1346,7 @@ static PyObject* New(PyTypeObject* cls,
 // The __init__ method of Message classes.
 // It initializes fields from keywords passed to the constructor.
 static int Init(CMessage* self, PyObject* args, PyObject* kwargs) {
-  if (PyTuple_Size(args) != 0) {
-    PyErr_SetString(PyExc_TypeError, "No positional arguments allowed");
-    return -1;
-  }
-
-  return InitAttributes(self, kwargs);
+  return InitAttributes(self, args, kwargs);
 }
 
 // ---------------------------------------------------------------------
@@ -1292,6 +1388,9 @@ struct ClearWeakReferences : public ChildVisitor {
 };
 
 static void Dealloc(CMessage* self) {
+  if (self->weakreflist) {
+    PyObject_ClearWeakRefs(reinterpret_cast<PyObject*>(self));
+  }
   // Null out all weak references from children to this message.
   GOOGLE_CHECK_EQ(0, ForEachCompositeField(self, ClearWeakReferences()));
   if (self->extensions) {
@@ -1459,18 +1558,20 @@ PyObject* HasField(CMessage* self, PyObject* arg) {
 }
 
 PyObject* ClearExtension(CMessage* self, PyObject* extension) {
+  const FieldDescriptor* descriptor = GetExtensionDescriptor(extension);
+  if (descriptor == NULL) {
+    return NULL;
+  }
   if (self->extensions != NULL) {
-    return extension_dict::ClearExtension(self->extensions, extension);
-  } else {
-    const FieldDescriptor* descriptor = GetExtensionDescriptor(extension);
-    if (descriptor == NULL) {
-      return NULL;
-    }
-    if (ScopedPyObjectPtr(ClearFieldByDescriptor(self, descriptor)) == NULL) {
-      return NULL;
+    PyObject* value = PyDict_GetItem(self->extensions->values, extension);
+    if (value != NULL) {
+      if (InternalReleaseFieldByDescriptor(self, descriptor, value) < 0) {
+        return NULL;
+      }
+      PyDict_DelItem(self->extensions->values, extension);
     }
   }
-  Py_RETURN_NONE;
+  return ClearFieldByDescriptor(self, descriptor);
 }
 
 PyObject* HasExtension(CMessage* self, PyObject* extension) {
@@ -1556,7 +1657,7 @@ int SetOwner(CMessage* self, const shared_ptr<Message>& new_owner) {
 Message* ReleaseMessage(CMessage* self,
                         const Descriptor* descriptor,
                         const FieldDescriptor* field_descriptor) {
-  MessageFactory* message_factory = GetFactoryForMessage(self);
+  MessageFactory* message_factory = GetFactoryForMessage(self)->message_factory;
   Message* released_message = self->message->GetReflection()->ReleaseMessage(
       self->message, field_descriptor, message_factory);
   // ReleaseMessage will return NULL which differs from
@@ -1593,23 +1694,20 @@ struct ReleaseChild : public ChildVisitor {
       parent_(parent) {}
 
   int VisitRepeatedCompositeContainer(RepeatedCompositeContainer* container) {
-    return repeated_composite_container::Release(
-        reinterpret_cast<RepeatedCompositeContainer*>(container));
+    return repeated_composite_container::Release(container);
   }
 
   int VisitRepeatedScalarContainer(RepeatedScalarContainer* container) {
-    return repeated_scalar_container::Release(
-        reinterpret_cast<RepeatedScalarContainer*>(container));
+    return repeated_scalar_container::Release(container);
   }
 
   int VisitMapContainer(MapContainer* container) {
-    return reinterpret_cast<MapContainer*>(container)->Release();
+    return container->Release();
   }
 
   int VisitCMessage(CMessage* cmessage,
                     const FieldDescriptor* field_descriptor) {
-    return ReleaseSubMessage(parent_, field_descriptor,
-        reinterpret_cast<CMessage*>(cmessage));
+    return ReleaseSubMessage(parent_, field_descriptor, cmessage);
   }
 
   CMessage* parent_;
@@ -1627,12 +1725,19 @@ int InternalReleaseFieldByDescriptor(
 
 PyObject* ClearFieldByDescriptor(
     CMessage* self,
-    const FieldDescriptor* descriptor) {
-  if (!CheckFieldBelongsToMessage(descriptor, self->message)) {
+    const FieldDescriptor* field_descriptor) {
+  if (!CheckFieldBelongsToMessage(field_descriptor, self->message)) {
     return NULL;
   }
   AssureWritable(self);
-  self->message->GetReflection()->ClearField(self->message, descriptor);
+  Message* message = self->message;
+  message->GetReflection()->ClearField(message, field_descriptor);
+  if (field_descriptor->cpp_type() == FieldDescriptor::CPPTYPE_ENUM &&
+      !message->GetReflection()->SupportsUnknownEnumValues()) {
+    UnknownFieldSet* unknown_field_set =
+        message->GetReflection()->MutableUnknownFields(message);
+    unknown_field_set->DeleteByNumber(field_descriptor->number());
+  }
   Py_RETURN_NONE;
 }
 
@@ -1668,27 +1773,17 @@ PyObject* ClearField(CMessage* self, PyObject* arg) {
     arg = arg_in_oneof.get();
   }
 
-  PyObject* composite_field = self->composite_fields ?
-      PyDict_GetItem(self->composite_fields, arg) : NULL;
-
-  // Only release the field if there's a possibility that there are
-  // references to it.
-  if (composite_field != NULL) {
-    if (InternalReleaseFieldByDescriptor(self, field_descriptor,
-                                         composite_field) < 0) {
-      return NULL;
+  // Release the field if it exists in the dict of composite fields.
+  if (self->composite_fields) {
+    PyObject* value = PyDict_GetItem(self->composite_fields, arg);
+    if (value != NULL) {
+      if (InternalReleaseFieldByDescriptor(self, field_descriptor, value) < 0) {
+        return NULL;
+      }
+      PyDict_DelItem(self->composite_fields, arg);
     }
-    PyDict_DelItem(self->composite_fields, arg);
-  }
-  message->GetReflection()->ClearField(message, field_descriptor);
-  if (field_descriptor->cpp_type() == FieldDescriptor::CPPTYPE_ENUM &&
-      !message->GetReflection()->SupportsUnknownEnumValues()) {
-    UnknownFieldSet* unknown_field_set =
-        message->GetReflection()->MutableUnknownFields(message);
-    unknown_field_set->DeleteByNumber(field_descriptor->number());
   }
-
-  Py_RETURN_NONE;
+  return ClearFieldByDescriptor(self, field_descriptor);
 }
 
 PyObject* Clear(CMessage* self) {
@@ -1899,11 +1994,15 @@ static PyObject* CopyFrom(CMessage* self, PyObject* arg) {
 // get OOM errors. The protobuf APIs do not provide any tools for processing
 // protobufs in chunks.  If you have protos this big you should break them up if
 // it is at all convenient to do so.
+#ifdef PROTOBUF_PYTHON_ALLOW_OVERSIZE_PROTOS
+static bool allow_oversize_protos = true;
+#else
 static bool allow_oversize_protos = false;
+#endif
 
 // Provide a method in the module to set allow_oversize_protos to a boolean
 // value. This method returns the newly value of allow_oversize_protos.
-static PyObject* SetAllowOversizeProtos(PyObject* m, PyObject* arg) {
+PyObject* SetAllowOversizeProtos(PyObject* m, PyObject* arg) {
   if (!arg || !PyBool_Check(arg)) {
     PyErr_SetString(PyExc_TypeError,
                     "Argument to SetAllowOversizeProtos must be boolean");
@@ -1930,8 +2029,8 @@ static PyObject* MergeFromString(CMessage* self, PyObject* arg) {
   if (allow_oversize_protos) {
     input.SetTotalBytesLimit(INT_MAX, INT_MAX);
   }
-  PyDescriptorPool* pool = GetDescriptorPoolForMessage(self);
-  input.SetExtensionRegistry(pool->pool, pool->message_factory);
+  PyMessageFactory* factory = GetFactoryForMessage(self);
+  input.SetExtensionRegistry(factory->pool->pool, factory->message_factory);
   bool success = self->message->MergePartialFromCodedStream(&input);
   if (success) {
     return PyInt_FromLong(input.CurrentPosition());
@@ -1952,99 +2051,29 @@ static PyObject* ByteSize(CMessage* self, PyObject* args) {
   return PyLong_FromLong(self->message->ByteSize());
 }
 
-static PyObject* RegisterExtension(PyObject* cls,
-                                   PyObject* extension_handle) {
+PyObject* RegisterExtension(PyObject* cls, PyObject* extension_handle) {
   const FieldDescriptor* descriptor =
       GetExtensionDescriptor(extension_handle);
   if (descriptor == NULL) {
     return NULL;
   }
-
-  ScopedPyObjectPtr extensions_by_name(
-      PyObject_GetAttr(cls, k_extensions_by_name));
-  if (extensions_by_name == NULL) {
-    PyErr_SetString(PyExc_TypeError, "no extensions_by_name on class");
+  if (!PyObject_TypeCheck(cls, &CMessageClass_Type)) {
+    PyErr_Format(PyExc_TypeError, "Expected a message class, got %s",
+                 cls->ob_type->tp_name);
     return NULL;
   }
-  ScopedPyObjectPtr full_name(PyObject_GetAttr(extension_handle, kfull_name));
-  if (full_name == NULL) {
+  CMessageClass *message_class = reinterpret_cast<CMessageClass*>(cls);
+  if (message_class == NULL) {
     return NULL;
   }
-
   // If the extension was already registered, check that it is the same.
-  PyObject* existing_extension =
-      PyDict_GetItem(extensions_by_name.get(), full_name.get());
-  if (existing_extension != NULL) {
-    const FieldDescriptor* existing_extension_descriptor =
-        GetExtensionDescriptor(existing_extension);
-    if (existing_extension_descriptor != descriptor) {
-      PyErr_SetString(PyExc_ValueError, "Double registration of Extensions");
-      return NULL;
-    }
-    // Nothing else to do.
-    Py_RETURN_NONE;
-  }
-
-  if (PyDict_SetItem(extensions_by_name.get(), full_name.get(),
-                     extension_handle) < 0) {
-    return NULL;
-  }
-
-  // Also store a mapping from extension number to implementing class.
-  ScopedPyObjectPtr extensions_by_number(
-      PyObject_GetAttr(cls, k_extensions_by_number));
-  if (extensions_by_number == NULL) {
-    PyErr_SetString(PyExc_TypeError, "no extensions_by_number on class");
+  const FieldDescriptor* existing_extension =
+      message_class->py_message_factory->pool->pool->FindExtensionByNumber(
+          descriptor->containing_type(), descriptor->number());
+  if (existing_extension != NULL && existing_extension != descriptor) {
+    PyErr_SetString(PyExc_ValueError, "Double registration of Extensions");
     return NULL;
   }
-
-  ScopedPyObjectPtr number(PyObject_GetAttrString(extension_handle, "number"));
-  if (number == NULL) {
-    return NULL;
-  }
-
-  // If the extension was already registered by number, check that it is the
-  // same.
-  existing_extension = PyDict_GetItem(extensions_by_number.get(), number.get());
-  if (existing_extension != NULL) {
-    const FieldDescriptor* existing_extension_descriptor =
-        GetExtensionDescriptor(existing_extension);
-    if (existing_extension_descriptor != descriptor) {
-      const Descriptor* msg_desc = GetMessageDescriptor(
-          reinterpret_cast<PyTypeObject*>(cls));
-      PyErr_Format(
-          PyExc_ValueError,
-          "Extensions \"%s\" and \"%s\" both try to extend message type "
-          "\"%s\" with field number %ld.",
-          existing_extension_descriptor->full_name().c_str(),
-          descriptor->full_name().c_str(),
-          msg_desc->full_name().c_str(),
-          PyInt_AsLong(number.get()));
-      return NULL;
-    }
-    // Nothing else to do.
-    Py_RETURN_NONE;
-  }
-  if (PyDict_SetItem(extensions_by_number.get(), number.get(),
-                     extension_handle) < 0) {
-    return NULL;
-  }
-
-  // Check if it's a message set
-  if (descriptor->is_extension() &&
-      descriptor->containing_type()->options().message_set_wire_format() &&
-      descriptor->type() == FieldDescriptor::TYPE_MESSAGE &&
-      descriptor->label() == FieldDescriptor::LABEL_OPTIONAL) {
-    ScopedPyObjectPtr message_name(PyString_FromStringAndSize(
-        descriptor->message_type()->full_name().c_str(),
-        descriptor->message_type()->full_name().size()));
-    if (message_name == NULL) {
-      return NULL;
-    }
-    PyDict_SetItem(extensions_by_name.get(), message_name.get(),
-                   extension_handle);
-  }
-
   Py_RETURN_NONE;
 }
 
@@ -2081,7 +2110,7 @@ static PyObject* WhichOneof(CMessage* self, PyObject* arg) {
 static PyObject* GetExtensionDict(CMessage* self, void *closure);
 
 static PyObject* ListFields(CMessage* self) {
-  vector<const FieldDescriptor*> fields;
+  std::vector<const FieldDescriptor*> fields;
   self->message->GetReflection()->ListFields(*self->message, &fields);
 
   // Normally, the list will be exactly the size of the fields.
@@ -2111,8 +2140,8 @@ static PyObject* ListFields(CMessage* self) {
       // is no message class and we cannot retrieve the value.
       // TODO(amauryfa): consider building the class on the fly!
       if (fields[i]->message_type() != NULL &&
-          cdescriptor_pool::GetMessageClass(
-              GetDescriptorPoolForMessage(self),
+          message_factory::GetMessageClass(
+              GetFactoryForMessage(self),
               fields[i]->message_type()) == NULL) {
         PyErr_Clear();
         continue;
@@ -2172,7 +2201,7 @@ static PyObject* DiscardUnknownFields(CMessage* self) {
 
 PyObject* FindInitializationErrors(CMessage* self) {
   Message* message = self->message;
-  vector<string> errors;
+  std::vector<string> errors;
   message->FindInitializationErrors(&errors);
 
   PyObject* error_list = PyList_New(errors.size());
@@ -2309,12 +2338,12 @@ PyObject* InternalGetScalar(const Message* message,
 PyObject* InternalGetSubMessage(
     CMessage* self, const FieldDescriptor* field_descriptor) {
   const Reflection* reflection = self->message->GetReflection();
-  PyDescriptorPool* pool = GetDescriptorPoolForMessage(self);
+  PyMessageFactory* factory = GetFactoryForMessage(self);
   const Message& sub_message = reflection->GetMessage(
-      *self->message, field_descriptor, pool->message_factory);
+      *self->message, field_descriptor, factory->message_factory);
 
-  CMessageClass* message_class = cdescriptor_pool::GetMessageClass(
-      pool, field_descriptor->message_type());
+  CMessageClass* message_class = message_factory::GetMessageClass(
+      factory, field_descriptor->message_type());
   if (message_class == NULL) {
     return NULL;
   }
@@ -2564,11 +2593,24 @@ static PyObject* GetExtensionDict(CMessage* self, void *closure) {
   return NULL;
 }
 
+static PyObject* GetExtensionsByName(CMessage *self, void *closure) {
+  return message_meta::GetExtensionsByName(
+      reinterpret_cast<CMessageClass*>(Py_TYPE(self)), closure);
+}
+
+static PyObject* GetExtensionsByNumber(CMessage *self, void *closure) {
+  return message_meta::GetExtensionsByNumber(
+      reinterpret_cast<CMessageClass*>(Py_TYPE(self)), closure);
+}
+
 static PyGetSetDef Getters[] = {
   {"Extensions", (getter)GetExtensionDict, NULL, "Extension dict"},
+  {"_extensions_by_name", (getter)GetExtensionsByName, NULL},
+  {"_extensions_by_number", (getter)GetExtensionsByNumber, NULL},
   {NULL}
 };
 
+
 static PyMethodDef Methods[] = {
   { "__deepcopy__", (PyCFunction)DeepCopy, METH_VARARGS,
     "Makes a deep copy of the class." },
@@ -2659,8 +2701,8 @@ PyObject* GetAttr(CMessage* self, PyObject* name) {
     const Descriptor* entry_type = field_descriptor->message_type();
     const FieldDescriptor* value_type = entry_type->FindFieldByName("value");
     if (value_type->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
-      CMessageClass* value_class = cdescriptor_pool::GetMessageClass(
-          GetDescriptorPoolForMessage(self), value_type->message_type());
+      CMessageClass* value_class = message_factory::GetMessageClass(
+          GetFactoryForMessage(self), value_type->message_type());
       if (value_class == NULL) {
         return NULL;
       }
@@ -2682,8 +2724,8 @@ PyObject* GetAttr(CMessage* self, PyObject* name) {
   if (field_descriptor->label() == FieldDescriptor::LABEL_REPEATED) {
     PyObject* py_container = NULL;
     if (field_descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
-      CMessageClass* message_class = cdescriptor_pool::GetMessageClass(
-          GetDescriptorPoolForMessage(self), field_descriptor->message_type());
+      CMessageClass* message_class = message_factory::GetMessageClass(
+          GetFactoryForMessage(self), field_descriptor->message_type());
       if (message_class == NULL) {
         return NULL;
       }
@@ -2778,7 +2820,7 @@ PyTypeObject CMessage_Type = {
   0,                                   //  tp_traverse
   0,                                   //  tp_clear
   (richcmpfunc)cmessage::RichCompare,  //  tp_richcompare
-  0,                                   //  tp_weaklistoffset
+  offsetof(CMessage, weakreflist),     //  tp_weaklistoffset
   0,                                   //  tp_iter
   0,                                   //  tp_iternext
   cmessage::Methods,                   //  tp_methods
@@ -2825,30 +2867,11 @@ static Message* MutableCProtoInsidePyProtoImpl(PyObject* msg) {
   return cmsg->message;
 }
 
-static const char module_docstring[] =
-"python-proto2 is a module that can be used to enhance proto2 Python API\n"
-"performance.\n"
-"\n"
-"It provides access to the protocol buffers C++ reflection API that\n"
-"implements the basic protocol buffer functions.";
-
 void InitGlobals() {
   // TODO(gps): Check all return values in this function for NULL and propagate
   // the error (MemoryError) on up to result in an import failure.  These should
   // also be freed and reset to NULL during finalization.
-  kPythonZero = PyInt_FromLong(0);
-  kint32min_py = PyInt_FromLong(kint32min);
-  kint32max_py = PyInt_FromLong(kint32max);
-  kuint32max_py = PyLong_FromLongLong(kuint32max);
-  kint64min_py = PyLong_FromLongLong(kint64min);
-  kint64max_py = PyLong_FromLongLong(kint64max);
-  kuint64max_py = PyLong_FromUnsignedLongLong(kuint64max);
-
   kDESCRIPTOR = PyString_FromString("DESCRIPTOR");
-  k_cdescriptor = PyString_FromString("_cdescriptor");
-  kfull_name = PyString_FromString("full_name");
-  k_extensions_by_name = PyString_FromString("_extensions_by_name");
-  k_extensions_by_number = PyString_FromString("_extensions_by_number");
 
   PyObject *dummy_obj = PySet_New(NULL);
   kEmptyWeakref = PyWeakref_NewRef(dummy_obj, NULL);
@@ -2866,6 +2889,11 @@ bool InitProto2MessageModule(PyObject *m) {
     return false;
   }
 
+  // Initialize types and globals in message_factory.cc
+  if (!InitMessageFactory()) {
+    return false;
+  }
+
   // Initialize constants defined in this file.
   InitGlobals();
 
@@ -2883,25 +2911,6 @@ bool InitProto2MessageModule(PyObject *m) {
   // DESCRIPTOR is set on each protocol buffer message class elsewhere, but set
   // it here as well to document that subclasses need to set it.
   PyDict_SetItem(CMessage_Type.tp_dict, kDESCRIPTOR, Py_None);
-  // Subclasses with message extensions will override _extensions_by_name and
-  // _extensions_by_number with fresh mutable dictionaries in AddDescriptors.
-  // All other classes can share this same immutable mapping.
-  ScopedPyObjectPtr empty_dict(PyDict_New());
-  if (empty_dict == NULL) {
-    return false;
-  }
-  ScopedPyObjectPtr immutable_dict(PyDictProxy_New(empty_dict.get()));
-  if (immutable_dict == NULL) {
-    return false;
-  }
-  if (PyDict_SetItem(CMessage_Type.tp_dict,
-                     k_extensions_by_name, immutable_dict.get()) < 0) {
-    return false;
-  }
-  if (PyDict_SetItem(CMessage_Type.tp_dict,
-                     k_extensions_by_number, immutable_dict.get()) < 0) {
-    return false;
-  }
 
   PyModule_AddObject(m, "Message", reinterpret_cast<PyObject*>(&CMessage_Type));
 
@@ -2947,69 +2956,15 @@ bool InitProto2MessageModule(PyObject *m) {
   }
 
   // Initialize Map container types.
-  {
-    // ScalarMapContainer_Type derives from our MutableMapping type.
-    ScopedPyObjectPtr containers(PyImport_ImportModule(
-        "google.protobuf.internal.containers"));
-    if (containers == NULL) {
-      return false;
-    }
-
-    ScopedPyObjectPtr mutable_mapping(
-        PyObject_GetAttrString(containers.get(), "MutableMapping"));
-    if (mutable_mapping == NULL) {
-      return false;
-    }
-
-    if (!PyObject_TypeCheck(mutable_mapping.get(), &PyType_Type)) {
-      return false;
-    }
-
-    Py_INCREF(mutable_mapping.get());
-#if PY_MAJOR_VERSION >= 3
-    PyObject* bases = PyTuple_New(1);
-    PyTuple_SET_ITEM(bases, 0, mutable_mapping.get());
-
-    ScalarMapContainer_Type = 
-        PyType_FromSpecWithBases(&ScalarMapContainer_Type_spec, bases);
-    PyModule_AddObject(m, "ScalarMapContainer", ScalarMapContainer_Type);
-#else
-    ScalarMapContainer_Type.tp_base =
-        reinterpret_cast<PyTypeObject*>(mutable_mapping.get());
-
-    if (PyType_Ready(&ScalarMapContainer_Type) < 0) {
-      return false;
-    }
-
-    PyModule_AddObject(m, "ScalarMapContainer",
-                       reinterpret_cast<PyObject*>(&ScalarMapContainer_Type));
-#endif
-
-    if (PyType_Ready(&MapIterator_Type) < 0) {
-      return false;
-    }
-
-    PyModule_AddObject(m, "MapIterator",
-                       reinterpret_cast<PyObject*>(&MapIterator_Type));
-
-
-#if PY_MAJOR_VERSION >= 3
-    MessageMapContainer_Type = 
-        PyType_FromSpecWithBases(&MessageMapContainer_Type_spec, bases);
-    PyModule_AddObject(m, "MessageMapContainer", MessageMapContainer_Type);
-#else
-    Py_INCREF(mutable_mapping.get());
-    MessageMapContainer_Type.tp_base =
-        reinterpret_cast<PyTypeObject*>(mutable_mapping.get());
-
-    if (PyType_Ready(&MessageMapContainer_Type) < 0) {
-      return false;
-    }
-
-    PyModule_AddObject(m, "MessageMapContainer",
-                       reinterpret_cast<PyObject*>(&MessageMapContainer_Type));
-#endif
+  if (!InitMapContainers()) {
+    return false;
   }
+  PyModule_AddObject(m, "ScalarMapContainer",
+                     reinterpret_cast<PyObject*>(ScalarMapContainer_Type));
+  PyModule_AddObject(m, "MessageMapContainer",
+                     reinterpret_cast<PyObject*>(MessageMapContainer_Type));
+  PyModule_AddObject(m, "MapIterator",
+                     reinterpret_cast<PyObject*>(&MapIterator_Type));
 
   if (PyType_Ready(&ExtensionDict_Type) < 0) {
     return false;
@@ -3044,6 +2999,10 @@ bool InitProto2MessageModule(PyObject *m) {
       &PyFileDescriptor_Type));
   PyModule_AddObject(m, "OneofDescriptor", reinterpret_cast<PyObject*>(
       &PyOneofDescriptor_Type));
+  PyModule_AddObject(m, "ServiceDescriptor", reinterpret_cast<PyObject*>(
+      &PyServiceDescriptor_Type));
+  PyModule_AddObject(m, "MethodDescriptor", reinterpret_cast<PyObject*>(
+      &PyMethodDescriptor_Type));
 
   PyObject* enum_type_wrapper = PyImport_ImportModule(
       "google.protobuf.internal.enum_type_wrapper");
@@ -3081,53 +3040,4 @@ bool InitProto2MessageModule(PyObject *m) {
 }  // namespace python
 }  // namespace protobuf
 
-static PyMethodDef ModuleMethods[] = {
-  {"SetAllowOversizeProtos",
-    (PyCFunction)google::protobuf::python::cmessage::SetAllowOversizeProtos,
-    METH_O, "Enable/disable oversize proto parsing."},
-  { NULL, NULL}
-};
-
-#if PY_MAJOR_VERSION >= 3
-static struct PyModuleDef _module = {
-  PyModuleDef_HEAD_INIT,
-  "_message",
-  google::protobuf::python::module_docstring,
-  -1,
-  ModuleMethods,  /* m_methods */
-  NULL,
-  NULL,
-  NULL,
-  NULL
-};
-#define INITFUNC PyInit__message
-#define INITFUNC_ERRORVAL NULL
-#else  // Python 2
-#define INITFUNC init_message
-#define INITFUNC_ERRORVAL
-#endif
-
-extern "C" {
-  PyMODINIT_FUNC INITFUNC(void) {
-    PyObject* m;
-#if PY_MAJOR_VERSION >= 3
-    m = PyModule_Create(&_module);
-#else
-    m = Py_InitModule3("_message", ModuleMethods,
-                       google::protobuf::python::module_docstring);
-#endif
-    if (m == NULL) {
-      return INITFUNC_ERRORVAL;
-    }
-
-    if (!google::protobuf::python::InitProto2MessageModule(m)) {
-      Py_DECREF(m);
-      return INITFUNC_ERRORVAL;
-    }
-
-#if PY_MAJOR_VERSION >= 3
-    return m;
-#endif
-  }
-}
 }  // namespace google