1 files changed, 58 insertions, 19 deletions

diff --git a/python/google/protobuf/pyext/extension_dict.cc b/python/google/protobuf/pyext/extension_dict.cc
index dbb7bca0..9423c1d8 100644
--- a/python/google/protobuf/pyext/extension_dict.cc
+++ b/python/google/protobuf/pyext/extension_dict.cc
@@ -38,6 +38,7 @@
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/dynamic_message.h>
 #include <google/protobuf/message.h>
+#include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/pyext/descriptor.h>
 #include <google/protobuf/pyext/message.h>
 #include <google/protobuf/pyext/message_factory.h>
@@ -46,6 +47,16 @@
 #include <google/protobuf/pyext/scoped_pyobject_ptr.h>
 #include <google/protobuf/stubs/shared_ptr.h>
 
+#if PY_MAJOR_VERSION >= 3
+  #if PY_VERSION_HEX < 0x03030000
+    #error "Python 3.0 - 3.2 are not supported."
+  #endif
+  #define PyString_AsStringAndSize(ob, charpp, sizep) \
+    (PyUnicode_Check(ob)? \
+       ((*(charpp) = PyUnicode_AsUTF8AndSize(ob, (sizep))) == NULL? -1: 0): \
+       PyBytes_AsStringAndSize(ob, (charpp), (sizep)))
+#endif
+
 namespace google {
 namespace protobuf {
 namespace python {
@@ -90,6 +101,7 @@ PyObject* subscript(ExtensionDict* self, PyObject* key) {
 
   if (descriptor->label() != FieldDescriptor::LABEL_REPEATED &&
       descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+    // TODO(plabatut): consider building the class on the fly!
     PyObject* sub_message = cmessage::InternalGetSubMessage(
         self->parent, descriptor);
     if (sub_message == NULL) {
@@ -101,7 +113,17 @@ PyObject* subscript(ExtensionDict* self, PyObject* key) {
 
   if (descriptor->label() == FieldDescriptor::LABEL_REPEATED) {
     if (descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
-      CMessageClass* message_class = message_factory::GetMessageClass(
+      // On the fly message class creation is needed to support the following
+      // situation:
+      // 1- add FileDescriptor to the pool that contains extensions of a message
+      //    defined by another proto file. Do not create any message classes.
+      // 2- instantiate an extended message, and access the extension using
+      //    the field descriptor.
+      // 3- the extension submessage fails to be returned, because no class has
+      //    been created.
+      // It happens when deserializing text proto format, or when enumerating
+      // fields of a deserialized message.
+      CMessageClass* message_class = message_factory::GetOrCreateMessageClass(
           cmessage::GetFactoryForMessage(self->parent),
           descriptor->message_type());
       if (message_class == NULL) {
@@ -154,34 +176,51 @@ int ass_subscript(ExtensionDict* self, PyObject* key, PyObject* value) {
   return 0;
 }
 
-PyObject* _FindExtensionByName(ExtensionDict* self, PyObject* name) {
-  ScopedPyObjectPtr extensions_by_name(PyObject_GetAttrString(
-      reinterpret_cast<PyObject*>(self->parent), "_extensions_by_name"));
-  if (extensions_by_name == NULL) {
+PyObject* _FindExtensionByName(ExtensionDict* self, PyObject* arg) {
+  char* name;
+  Py_ssize_t name_size;
+  if (PyString_AsStringAndSize(arg, &name, &name_size) < 0) {
     return NULL;
   }
-  PyObject* result = PyDict_GetItem(extensions_by_name.get(), name);
-  if (result == NULL) {
+
+  PyDescriptorPool* pool = cmessage::GetFactoryForMessage(self->parent)->pool;
+  const FieldDescriptor* message_extension =
+      pool->pool->FindExtensionByName(string(name, name_size));
+  if (message_extension == NULL) {
+    // Is is the name of a message set extension?
+    const Descriptor* message_descriptor = pool->pool->FindMessageTypeByName(
+        string(name, name_size));
+    if (message_descriptor && message_descriptor->extension_count() > 0) {
+      const FieldDescriptor* extension = message_descriptor->extension(0);
+      if (extension->is_extension() &&
+          extension->containing_type()->options().message_set_wire_format() &&
+          extension->type() == FieldDescriptor::TYPE_MESSAGE &&
+          extension->label() == FieldDescriptor::LABEL_OPTIONAL) {
+        message_extension = extension;
+      }
+    }
+  }
+  if (message_extension == NULL) {
     Py_RETURN_NONE;
-  } else {
-    Py_INCREF(result);
-    return result;
   }
+
+  return PyFieldDescriptor_FromDescriptor(message_extension);
 }
 
-PyObject* _FindExtensionByNumber(ExtensionDict* self, PyObject* number) {
-  ScopedPyObjectPtr extensions_by_number(PyObject_GetAttrString(
-      reinterpret_cast<PyObject*>(self->parent), "_extensions_by_number"));
-  if (extensions_by_number == NULL) {
+PyObject* _FindExtensionByNumber(ExtensionDict* self, PyObject* arg) {
+  int64 number = PyLong_AsLong(arg);
+  if (number == -1 && PyErr_Occurred()) {
     return NULL;
   }
-  PyObject* result = PyDict_GetItem(extensions_by_number.get(), number);
-  if (result == NULL) {
+
+  PyDescriptorPool* pool = cmessage::GetFactoryForMessage(self->parent)->pool;
+  const FieldDescriptor* message_extension = pool->pool->FindExtensionByNumber(
+      self->parent->message->GetDescriptor(), number);
+  if (message_extension == NULL) {
     Py_RETURN_NONE;
-  } else {
-    Py_INCREF(result);
-    return result;
   }
+
+  return PyFieldDescriptor_FromDescriptor(message_extension);
 }
 
 ExtensionDict* NewExtensionDict(CMessage *parent) {