BIND 10 #2087: add LabelSequence::getOffsetData() method

[BIND 10 Development]

#2087: add LabelSequence::getOffsetData() method
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                   Reporter:         |                 Owner:  muks
  jinmei                             |                Status:  reviewing
                       Type:  task   |             Milestone:
                   Priority:         |  Sprint-20120717
  medium                             |            Resolution:
                  Component:         |             Sensitive:  0
  libdns++                           |           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 muks):

 Replying to [comment:9 jelte]:
 > if you pull out data and offsets, you cannot use them to create a new
 labelsequence, or at least, not one with the same properties as the one
 you got the data from; the isAbsolute() property is 'reset' to true in the
 new object (because of the way that property is stored/checked). This
 could potentially also change comparison behaviour

 The code that uses this data would have to be careful about it. We could
 add a constructor argument (bool not_absolute), something like this:

 {{{
 diff --git a/src/lib/dns/labelsequence.cc b/src/lib/dns/labelsequence.cc
 index 7627571..31a7bd8 100644
 --- a/src/lib/dns/labelsequence.cc
 +++ b/src/lib/dns/labelsequence.cc
 @@ -25,11 +25,13 @@ namespace dns {

  LabelSequence::LabelSequence(const uint8_t* data,
                               const uint8_t* offsets,
 -                             size_t offsets_size) : data_(data),
 +                             size_t offsets_size,
 +                             bool not_absolute) :   data_(data),
                                                      offsets_(offsets),
 offsets_size_(offsets_size),
                                                      first_label_(0),
 -
 last_label_(offsets_size_)
 +
 last_label_(offsets_size_),
 +
 init_not_absolute_(not_absolute)
  {
      if (data == NULL || offsets == NULL) {
          isc_throw(BadValue, "Null pointer passed to LabelSequence
 constructor");
 @@ -214,7 +216,7 @@ LabelSequence::stripRight(size_t i) {

  bool
  LabelSequence::isAbsolute() const {
 -    return (last_label_ == offsets_size_);
 +    return ((last_label_ == offsets_size_) && (!init_not_absolute_));
  }

  size_t
 diff --git a/src/lib/dns/labelsequence.h b/src/lib/dns/labelsequence.h
 index 48f3241..d5efd27 100644
 --- a/src/lib/dns/labelsequence.h
 +++ b/src/lib/dns/labelsequence.h
 @@ -60,7 +60,8 @@ public:
                                       offsets_(ls.offsets_),
                                       offsets_size_(ls.offsets_size_),
                                       first_label_(ls.first_label_),
 -                                     last_label_(ls.last_label_)
 +                                     last_label_(ls.last_label_),
 +
 init_not_absolute_(ls.init_not_absolute_)
      {}

      /// \brief Constructs a LabelSequence for the given name
 @@ -76,7 +77,8 @@ public:
                                       offsets_(&name.offsets_[0]),
                                       offsets_size_(name.offsets_.size()),
                                       first_label_(0),
 -                                     last_label_(name.getLabelCount())
 +                                     last_label_(name.getLabelCount()),
 +                                     init_not_absolute_(false)
      {}

      /// \brief Constructs a LabelSequence for the given data
 @@ -96,7 +98,8 @@ public:
      /// \param offsets_size The size of the offsets data
      LabelSequence(const uint8_t* data,
                    const uint8_t* offsets,
 -                  size_t offsets_size);
 +                  size_t offsets_size,
 +                  bool not_absolute = false);

      /// \brief Return the wire-format data for this LabelSequence
      ///
 @@ -257,6 +260,7 @@ private:
      size_t offsets_size_;
      size_t first_label_;
      size_t last_label_;
 +    const bool init_not_absolute_;
  };
 }}}

 Let's discuss and if we want this, we'll implement it in a separate
 ticket.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2087#comment:10>
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