[tahoe-lafs-trac-stream] [tahoe-lafs] #993: refactor download interfaces to treat immutable files and mutable versions more uniformly

[tahoe-lafs]

#993: refactor download interfaces to treat immutable files and mutable versions
more uniformly
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     Reporter:  davidsarah    |      Owner:  kevan
         Type:  enhancement   |     Status:  new
     Priority:  major         |  Milestone:  1.9.0
    Component:  code-mutable  |    Version:  1.6.0
   Resolution:                |   Keywords:  cleanup download mutable
Launchpad Bug:                |
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Comment (by davidsarah):

 In ticket:413#comment:5, zooko said:
 > "roothash" means the root of the Merkle Tree over the (encrypted) shares
 of one specific version of the file, so it is sufficient to uniquely
 identify one version. Yes, everything that talks about "versions" of
 mutable files should specify the version as a {{{(sequence_number,
 roothash)}}} tuple.

 This affects the new {{{IMutableFileversion}}} interface in
 {{{interfaces.py}}}: it should either grow a {{{get_roothash()}}} method,
 or {{{get_sequence_number()}}} should be changed to
 {{{get_sequence_number_and_roothash()}}} (or some more concise name) that
 returns a pair.

 (The object represents a particular version, so a single method returning
 a pair is not necessary to avoid race conditions.)

-- 
Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/993#comment:14>
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