BIND 10 #1775: update in-memory getAdditional() to handle wildcard match for additional names

[BIND 10 Development]

#1775: update in-memory getAdditional() to handle wildcard match for additional
names
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                   Reporter:         |                 Owner:  jinmei
  jinmei                             |                Status:  accepted
                       Type:  task   |             Milestone:
                   Priority:  high   |  Sprint-20120403
                  Component:         |            Resolution:
  Unclassified                       |             Sensitive:  0
                   Keywords:         |           Sub-Project:  DNS
            Defect Severity:  N/A    |  Estimated Difficulty:  5
Feature Depending on Ticket:  auth   |           Total Hours:  0
  performance                        |
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Comment (by jinmei):

 trac1775 is ready for review.

 The first 3 commits are actually just set up.  It's basically an
 internal refactoring so we can share the code logic of identifying
 the bestmaching node for a given name in the zone.  To do so
 I extracted the first part of InMemoryZoneFinderImpl::find() to
 a separate function and moved it to the ZoneData structure.
 The first commit (beb36d9) is the main part of this refactoring,
 and it should essentially be straightforward extraction.  The diff
 of this commit itself is pretty large, however, so it's probably
 easier to review the branch if this commit is first checked
 separately.

 I also believe this refactoring is a good cleanup even if it's not for
 this task so the find() function is more concise and readable (see
 also #578).

 The 2nd and 3rd commits are setup for the main change by changing
 addAdditional() to use the extracted function.

 The last commit was the main change.  I believe this one is pretty
 easy to understand.  As noted, this change involves heavy copies that
 could be avoided if our goal is to minimize memory footprint.  But
 also as noted, I believe this should actually be a pretty rare case in
 practice, so I think it should be acceptable.  (Total memory footprint
 is still an issue, but that applies for the entire data structure, and
 we'll need to revisit the whole design fundamentally anyway.  We can
 revisit the memory footprint for this particular point at that point).

 I don't plan to add a changelog for this task.

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Ticket URL: <http://bind10.isc.org/ticket/1775#comment:4>
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