.

bigfile/file_zodb.py

@@ -127,6 +127,27 @@ will be our future approach after we teach NEO about object deduplication.
 #
 # TODO add top-level overview
 #
+#   zfile   (ZBigFile)
+#       .blksize
+#       .blktab     LOBTree #blk -> ZBlk*
+#
+#       ._v_file        _ZBigFile
+#       ._v_filehset    weakset(_ZBigFileH) created for zfile
+#
+#   zfileh  (_ZBigFileH)
+#
+# ZBigFile is kept as Live persistent because XXX
+#
+#
+#   DB -> ZBlk.blkdata  (-> memory-page)
+#   (DB <- )  ZBlk.blkdata <- memory-page
+#
+#   (DB -> invalidate ZBlk.blkdata -> invalidate memory-page)
+#   + FIXME topology changes are not handled correctly
+#   + FIXME ZBlk is ghostified
+#
+#
+#
 # As file pages are changed in RAM with changes being managed by virtmem
 # subsystem, we need to propagate the changes to ZODB objects back at some time.
 #
@@ -630,6 +651,9 @@ class ZBigFile(LivePersistent):
     # - True    -> use wcfs
     # - False   -> don't use wcfs
     # - not set -> behave according to global default
+    #
+    # XXX several fileh could be opened for one ZBigFile. Is it useful at all?
+    #     normally in one zconn there is only one zfileh opened for zfile.
     def fileh_open(self, _use_wcfs=None):
         if _use_wcfs is None:
             _use_wcfs = self._default_use_wcfs()
@@ -730,13 +754,12 @@ Connection.open = Connection_open
 @implementer(ISynchronizer)
 class _ZBigFileH(object):
     # .zfile        ZBigFile we were opened for
-#   # .wcfileh      handle for ZBigFile in wcfs | None
+    # .wcfileh      handle for ZBigFile in wcfs | None
     # .zfileh       handle for ZBigFile (overlayed over .wcfileh if .wcfileh != ø)
 
-#   def __init__(self, zfile, wcfileh):
-    def __init__(self, zfile, wc):  # wc: wcfs.WCFS | None
+    def __init__(self, zfile, wcfileh):
         self.zfile   = zfile
-#       self.wcfileh = wcfileh
+        self.wcfileh = wcfileh
         self.zfileh = zfile._v_file.fileh_open()    # XXX pass wcfileh in
 
         # FIXME zfile._p_jar could be None (ex. ZBigFile is newly created