BIND 10 #2428: support $INCLUDE in dns::MasterLoader

[BIND 10 Development]

#2428: support $INCLUDE in dns::MasterLoader
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            Reporter:  jinmei        |                        Owner:
                Type:  task          |  vorner
            Priority:  medium        |                       Status:
           Component:  libdns++      |  reviewing
            Keywords:                |                    Milestone:
           Sensitive:  0             |  Sprint-20121218
         Sub-Project:  DNS           |                   Resolution:
Estimated Difficulty:  3             |                 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 jelte):

 * owner:  jelte => vorner


Comment:

 A few more comments:

 We should probably put !InternalException into an unnamed namespace

 master_loader:

 Any specific reason why source_count_ is kept separately and not through
 size() in the internal vector? (something like
 MasterLexer::getSourceCount() { return impl_->sources.size() })

 I don't think BIND9 does this either, but I wonder if we should consider
 limiting the number of $includes that can be nested. One would run out of
 open files quite quickly if a zone file includes itself, but we may want
 to catch that before the system does (so we can error with 'too many
 nested includes' rather than 'too many open files').

 unit tests:

 i see the UNKNOWN 'directive' is checked, should we also check things like
 $INCLUD and $INCLUDES (i.e. 1 letter too little or too much)?

-- 
Ticket URL: <https://bind10.isc.org/ticket/2428#comment:7>
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