.

bigfile/_file_zodb.pyx

 # -*- coding: utf-8 -*-
-# Wendelin.bigfile | BigFile ZODB backend
+# Wendelin.bigfile | WCFS part of BigFile ZODB backend
 # Copyright (C) 2014-2019  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
@@ -53,11 +53,14 @@ cdef extern from *:
 from wcfs.internal cimport _wcfs as wcfs
 from golang cimport nil
 
+from ZODB.utils import u64
+
 # helper for ZBigFile - just redirect loadblk/storeblk back
 # (because it is not possible to inherit from both Persistent and BigFile at
 #  the same time - see below)
 cdef class _ZBigFile(BigFile):
     cdef object     zself   # reference to ZBigFile
+    cdef wcfs.Oid   foid    # = .zself._p_oid
     cdef wcfs.Conn  wconn   # WCFS connection   XXX -> zconn instead ?  XXX wconn is shared between files
 
     # XXX Cython does not allow __new__ nor to change arguments passed to __cinit__ / __init__
@@ -65,6 +68,8 @@ cdef class _ZBigFile(BigFile):
     def _new(zself, blksize):
         cdef _ZBigFile obj = _ZBigFile.__new__(_ZBigFile, blksize)
         obj.zself = zself
+        obj.foid  = -1  # Note: zself._p_oid could be yet None for newly created ZBigFile
+        obj.wconn = nil # XXX
         return obj
 
     def __dealloc__(_ZBigFile zf):