BIND 10 #2105: introduce node deleter of new RBTree

[BIND 10 Development]

#2105: introduce node deleter of new RBTree
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                   Reporter:         |                 Owner:  UnAssigned
  jinmei                             |                Status:  reviewing
                       Type:  task   |             Milestone:
                   Priority:         |  Sprint-20120731
  medium                             |            Resolution:
                  Component:  data   |             Sensitive:  0
  source                             |           Sub-Project:  DNS
                   Keywords:         |  Estimated Difficulty:  4
            Defect Severity:  N/A    |           Total Hours:  0
Feature Depending on Ticket:         |
  scalable inmemory                  |
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Comment (by jinmei):

 (Although I don't think I can take on full review) some things I've
 noticed:
 - it didn't compile for me because `DeleterType` doesn't have the
   constructor explicitly defined.  my compiler rejects a const instant
   of it without the default constructor:
 {{{#!cpp
 class DeleterType {
 public:
     DeleterType() {}
 ...
 };
 }}}
 - I suspect we need to pass a `MemorySegment` to the deleter's
   operator() (or whatever actually deletes the data).  We'll use a
   segment when we actually use it for `RdataSet`.
 - I'm not sure if it's a good behavior to autoamtically delete
   existing data on setData().  I'm also not sure if we can pass NULL
   to the deleter.  please discuss this with the reviwer.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2105#comment:7>
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