Mailing-List: contact j-dev-help@xerces.apache.org; run by ezmlm
Precedence: bulk
Reply-To: j-dev@xerces.apache.org
Date: Sat, 14 May 2011 17:12:47 +0000 (UTC)
From: "Michael Glavassevich (JIRA)" <xerces-j-dev@xml.apache.org>
To: j-dev@xerces.apache.org
Message-ID: 
 <2019025677.13298.1305393167311.JavaMail.tomcat@hel.zones.apache.org>
Subject: [jira] [Commented] (XERCESJ-1421) Temporary inconsistent data
 inside Xerces2-J when removing a first child of a node.
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable


    [ https://issues.apache.org/jira/browse/XERCESJ-1421?page=3Dcom.atlassi=
an.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=3D13=
033581#comment-13033581 ]=20

Michael Glavassevich commented on XERCESJ-1421:
-----------------------------------------------

Ludger and Thiwanka, I agree with both or your assessments. This not only c=
orrects an inconsistent state but is also minor performance improvement for=
 checkNormalizationAfterRemove() when the first child of a node is removed.

> Temporary inconsistent data inside Xerces2-J when removing a first child =
of a node.
> -------------------------------------------------------------------------=
----------
>
>                 Key: XERCESJ-1421
>                 URL: https://issues.apache.org/jira/browse/XERCESJ-1421
>             Project: Xerces2-J
>          Issue Type: Improvement
>          Components: DOM (Level 3 Core)
>    Affects Versions: 2.9.1
>            Reporter: Ludger B=C3=BCnger
>            Assignee: Michael Glavassevich
>            Priority: Minor
>         Attachments: PreviousSiblingInconsistentDataPatch.txt
>
>
> When removing a first child, currently there is a local field inside Pare=
ntNode.internalRemoveChild that contains inconsistent data.
> Since in this specific case the following code still performs correct, th=
ere is currently no harm done.
> However I think it should be fixed nonetheless since future changes to th=
e code might cause problems.
> And here the description of the issue:
> Xerces2-J uses an internal optimization by overloading the ChildNode.prev=
iousSibling field.
> 1) If a node has a previous sibling, this field contains the previous sib=
ling.
> 2) if a node is the first child of it's parent (and thus has no previous =
sibling), this field is re-used for a different purpose and contains the la=
st sibling thus allowing quick access to the end of a node list
> Now ChildNode.internalRemoveNode stores a reference to the previousSiblin=
g of the removed node for normalization checking purposes in the local fiel=
d oldPreviousSibling.
> However this is done after removal of the node is already done but before=
 null'ing of the tree structure fields of the node.
> Since this node has already been removed, the isFirstChild() check fails =
and instead of 'null' the last sibling is stored in the oldPreviousSibling =
field.
> By chance the normalization checking code still works correct if the prev=
ious sibling field contains the last sibling instead of the correct value '=
null' but this still should be fixed.
> See attached patch.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira

---------------------------------------------------------------------
To unsubscribe, e-mail: j-dev-unsubscribe@xerces.apache.org
For additional commands, e-mail: j-dev-help@xerces.apache.org