[tahoe-dev] [tahoe-lafs] #329: dirnodes could cache encrypted/serialized entries for speed

[tahoe-lafs]

#329: dirnodes could cache encrypted/serialized entries for speed
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 Reporter:  warner         |           Owner:  kevan    
     Type:  enhancement    |          Status:  new      
 Priority:  minor          |       Milestone:  undecided
Component:  code-dirnodes  |         Version:  0.8.0    
 Keywords:  dirnode        |   Launchpad_bug:           
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Comment(by kevan):

 That fixed the issue -- thanks.

 Just so I'm clear on the next part:

 Currently, {{{_unpack_contents}}} returns a dictionary mapping the name of
 each child node to a pair {{{(child node instance, metadata)}}}, where
 metadata is a dictionary of metadata. {{{_pack_contents}}} gets the
 {{{rocap}}} and {{{rwcap}}} (if present) from the child node instance.
 What we want to do is

  * Modify {{{_unpack_contents}}} to return a dict mapping the name of each
 child node to a triple {{{(child node instance, metadata, serialized)}}},
 where child node instance and metadata are as they are now, and serialized
 is the serialized from of the other data.
  * Modify {{{_pack_contents}}} to deal with this new representation;
 specifically, to use {{{serialized}}} if present instead of serializing
 the other data, which we think is expensive.
  * Modify {{{Adder}}}, {{{MetadataSetter}}} and {{{Deleter}}} to work with
 these changes; specifically, they should, when modifying a node, set the
 corresponding {{{serialized}}} value to None, which will tell
 {{{_pack_contents}}} that it needs to re-serialize that node.
  * Write tests to make sure that all of this works (probably before doing
 the first 3 items). In particular,
    * If we pass contents packed with an unmodified {{{_pack_contents}}} to
 the new {{{_unpack_contents}}}, we should get the same underlying
 directory structure back (i.e.: all expected child node names are present,
 and metadata values are as they should be. Is there anything else we'd
 want to check?)
    * The output of the new {{{_pack_contents}}} should be the same as the
 output from the old one, given the same directory structure.
    * We should be able to interact with {{{Adder}}}, {{{Deleter}}}, and
 {{{MetadataSetter}}} in the same way that we do now. Are there already
 tests to adequately verify this, or should I plan on writing those, too?

 (apologies if this is pedantic, but I'm still getting the hang of tahoe,
 and don't want to go off on an irrelevant tangent because I've made a bad
 assumption somewhere)

-- 
Ticket URL: <http://allmydata.org/trac/tahoe/ticket/329#comment:9>
tahoe-lafs <http://allmydata.org>
secure decentralized file storage grid