BIND 10 #1060: introduce the abstract DataSourceClient and ZoneHandle classes

[BIND 10 Development]

#1060: introduce the abstract DataSourceClient and ZoneHandle classes
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                   Reporter:         |                 Owner:  jinmei
  jinmei                             |                Status:  reviewing
                       Type:  task   |             Milestone:
                   Priority:  major  |  Sprint-20110802
                  Component:  data   |            Resolution:
  source                             |             Sensitive:  0
                   Keywords:         |           Sub-Project:  DNS
            Defect Severity:  N/A    |  Estimated Difficulty:  5.0
Feature Depending on Ticket:         |           Total Hours:  0
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Comment (by jinmei):

 Replying to [comment:7 vorner]:
 > I think it should be ready for review. The in-memory data source is
 inherited from it, with some renaming, etc.
 >
 > However, the DataSourceClient class is not complete, I didn't add any of
 the functions allowing modifications or iterating trough the whole zone. I
 think these can be added when they are needed (either when they are used
 or when some backend would like to implement it), as I wouldn't guess the
 interface right anyway.
 >
 > I hope I understand the general direction of refactoring correctly. If
 not, please point it out.

 Thanks for taking this on.  Your changes generally look good.

 I've made some additional documentation fixes to the branch directly.
 In addition to trivial fixes like correcting typo, it contains:
 - more detailed and more complete documentation for the DataSourceClient
 class
 - update the text around ZoneFinder - no that it's an accessor rather than
   a zone itself, some of the original text like "NS record in ZoneFinder"
   do not really make sense.  I've updated those.
 I suspect there are other cases where we'd need to make this type of
 changes, but since this is a blocking ticket and it's unlikely for me
 to find time for comprehensive re-read and fix, I suggest we move on
 and fix them in subsequent tickets as we find them.

 A few more points:
 - maybe we shoud rename variables like 'zone' to 'zone_finder' (or if
   it's too long something like 'zfinder')
 - MemoryZoneFinder should be named InMemoryZoneFinder (for
   consistency)?
 - I think InMemoryClient::addZone() should better take
   MemoryZoneFinder (because it's specific to this derived class), but
   I found it would require changes to auth server tests and may make
   this branch unnecessarily big.  So I'm okay to defer it to a
   separate ticket.

-- 
Ticket URL: <http://bind10.isc.org/ticket/1060#comment:9>
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