[tahoe-lafs-trac-stream] [tahoe-lafs] #393: mutable: implement MDMF

[tahoe-lafs]

#393: mutable: implement MDMF
-------------------------+-------------------------------------------------
     Reporter:  warner   |      Owner:  zooko
         Type:           |     Status:  new
  enhancement            |  Milestone:  1.9.0
     Priority:  major    |    Version:  1.0.0
    Component:  code-    |   Keywords:  newcaps performance random-access
  mutable                |  privacy gsoc mdmf mutable backward-
   Resolution:           |  compatibility forward-compatibility review-
Launchpad Bug:           |  needed
-------------------------+-------------------------------------------------

Comment (by zooko):

 No sooner had I posted attachment:choose_segs.py than I realized I had
 forgotten an important case—the case where your write doesn't overwrite
 the entire last segment of your write, but it is also the last segment of
 the current version of the file and your write overwrites all of the bytes
 in the current version of the file.

 So then no sooner had I posted attachment:choose_segs2.py, which fixed
 that, that I realized I had also forgotten the case that your write of the
 ''first'' segment is not overwriting the entire segment but is overwriting
 all of the bytes in that segment in the current version of the file
 (because it is also the last segment of your write and the last segment of
 the current version of the file). So here is attachment:choose_segs3.py.
 This sort of arithmetic is annoyingly hard, and I'm sleepy, so I wouldn't
 be surprised if there are more mistakes like that in there.

 Still no tests. Perhaps attachment:choose_segs3.py could ''be'' the tests
 for
 [source:trunk/src/allmydata/mutable/publish.py?annotate=blame&rev=5231#L1266
 TransformingUploadable]...

-- 
Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/393#comment:162>
tahoe-lafs <http://tahoe-lafs.org>
secure decentralized storage