BIND 10 #2092: RBNode parent pointer updates

[BIND 10 Development]

#2092: RBNode parent pointer updates
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                   Reporter:         |                 Owner:  muks
  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:  2.06
Feature Depending on Ticket:         |
  scalable inmemory                  |
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Changes (by vorner):

 * owner:  vorner => muks
 * totalhours:  0 => 2.06


Comment:

 Hello

 Replying to [comment:17 muks]:
 > Replying to [comment:15 jinmei]:
 > > The code looks mostly OK, but:
 > >  * The rebasing is not good for reviewing. Since rebasing could have
 changed (or you, because of the conflicts) the old commits, I needed to
 review the whole thing once again.
 >
 > I am very sorry. I'll do merges from now on. In this particular case,
 the commits are still identical to the last ones (if that is any
 consolation).

 That's OK. I just wanted to point it out. If you said before the review
 the commits are the same, it would help also.

 > >  * Inspired by what Jinmei mentioned yesterday in Jabber, this (and
 similar ones) looks unsafe:
 > > {{{#!c++
 > > if (parent == parent->getParent()->getLeft())
 > > }}}
 > >    The code checks only that the node is not root, so the parent can
 be. And it could be the root of the top-most tree, in which case the
 parent would be NULL. So parent->getParent() would return NULL and the
 getLeft would segfault. I think this is one of the places where the code
 assumed the link-to-self property of the sentinel.
 >
 > In our trees, root is always black. So the dereference will always work.

 Could you put a comment above the condition, explaining why it is safe?

 After that, please merge.

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Ticket URL: <https://bind10.isc.org/ticket/2092#comment:18>
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