Down-integrate from internal code base.

1 files changed, 16 insertions, 6 deletions

diff --git a/python/google/protobuf/pyext/extension_dict.h b/python/google/protobuf/pyext/extension_dict.h
index 13c874a4..47625e23 100644
--- a/python/google/protobuf/pyext/extension_dict.h
+++ b/python/google/protobuf/pyext/extension_dict.h
@@ -53,13 +53,26 @@ using internal::shared_ptr;
 namespace python {
 
 struct CMessage;
-struct CFieldDescriptor;
 
 typedef struct ExtensionDict {
   PyObject_HEAD;
+
+  // This is the top-level C++ Message object that owns the whole
+  // proto tree.  Every Python container class holds a
+  // reference to it in order to keep it alive as long as there's a
+  // Python object that references any part of the tree.
   shared_ptr<Message> owner;
+
+  // Weak reference to parent message. Used to make sure
+  // the parent is writable when an extension field is modified.
   CMessage* parent;
+
+  // Pointer to the C++ Message that this ExtensionDict extends.
+  // Not owned by us.
   Message* message;
+
+  // A dict of child messages, indexed by Extension descriptors.
+  // Similar to CMessage::composite_fields.
   PyObject* values;
 } ExtensionDict;
 
@@ -67,11 +80,8 @@ extern PyTypeObject ExtensionDict_Type;
 
 namespace extension_dict {
 
-// Gets the _cdescriptor reference to a CFieldDescriptor object given a
-// python descriptor object.
-//
-// Returns a new reference.
-CFieldDescriptor* InternalGetCDescriptorFromExtension(PyObject* extension);
+// Builds an Extensions dict for a specific message.
+ExtensionDict* NewExtensionDict(CMessage *parent);
 
 // Gets the number of extension values in this ExtensionDict as a python object.
 //