BIND 10 #2440: add support for "merging" RRsets into memory::RdataSet

[BIND 10 Development]

#2440: add support for "merging" RRsets into memory::RdataSet
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            Reporter:  jinmei        |                        Owner:
                Type:  task          |  jinmei
            Priority:  medium        |                       Status:
           Component:  data source   |  reviewing
            Keywords:                |                    Milestone:
           Sensitive:  0             |  Sprint-20130305
         Sub-Project:  DNS           |                   Resolution:
Estimated Difficulty:  6             |                 CVSS Scoring:
         Total Hours:  0             |              Defect Severity:  N/A
                                     |  Feature Depending on Ticket:
                                     |  loadzone-ng
                                     |          Add Hours to Ticket:  0
                                     |                    Internal?:  0
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Changes (by vorner):

 * owner:  vorner => jinmei


Comment:

 Just the usual list of details:

 Here, the use of bind seems unnecessary. I believe `boost::function`
 accept direct function objects and this binds no variables, so the
 creation of the object is just overhead:
 {{{#!c++
                          rdatas_(boost::bind(RdataLess, _1, _2)),
                          rrsigs_(boost::bind(RdataLess, _1, _2))
 }}}

 In this bit of code, I started to wonder if you want to sum the lengths
 with or without the duplicities. After a while, I found out it doesn't
 matter, because the serialized data should contain no duplicate records.
 However, there might be a note in the code pointing this out, it would
 have saved me some time.

 Description of the new start does say the old data must stay valid for the
 whole time of rendering. But I believe it is worth noting the old data can
 be freed after the rendering is done. I'd otherwise wonder if the data is
 copied or just referenced from the new representation, or if the data is
 somehow reused.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2440#comment:19>
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