Bug 64072 - [Meta] "Flattened tree" concept should be explicit in the code
: [Meta] "Flattened tree" concept should be explicit in the code
Status: RESOLVED DUPLICATE of bug 79197
: WebKit
HTML DOM
: 528+ (Nightly build)
: Unspecified Unspecified
: P2 Normal
Assigned To:
:
:
: 61110 64144 64251 64849 64850
: 63522 72352
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Reported: 2011-07-07 01:13 PST by
Modified: 2012-02-27 19:02 PST (History)


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Description From 2011-07-07 01:13:03 PST
Working on Bug 63977, It became clear that we should have a way to beware "flattened tree" concept in XBL mean.

Here is a rough idea:
- At first, extract NodeFlattener from NodeRenderingContext.
- Then expand its usage to where we should care about flattened tree:
  - Focus handling,
  - Text iteration,
  - And possibly more!

NodeFlattener would look like this:
----
class NodeFlattener
{
public:
    Node* nextSibling() const;
    Node* previousSibling() const;
    Node* parent() const;
    Node* next() const; // dfs traversal like traverseNextNode()

    void moveToNextSibling();
    .... // more moveTo family will come here.
private:
    Node* m_node;
   ... // Pull a part of NodeRenderingContext state here.
};
----

NodeFlattener is like TreeWalker, but should be more lightweight.
- It doesn't have script binding.
- It's stack-based.
Ideally, it would be great if the flattener can be used as a smart pointer for the node.
But I think it isn't feasible because it has a many state
which makes a copy operation bit expensive.
------- Comment #1 From 2011-07-07 01:33:36 PST -------
Bug 61110 might relates.
------- Comment #2 From 2011-07-07 07:52:31 PST -------
I think "Flattener" is a completely wrong term here. It's just a tree walker, aware of shadow DOM subtrees.

Can we call it TreeIterator instead?
------- Comment #3 From 2011-07-07 18:33:52 PST -------
(In reply to comment #2)
> I think "Flattener" is a completely wrong term here. It's just a tree walker, aware of shadow DOM subtrees.
> 
> Can we call it TreeIterator instead?
That sounds fine. It's a bit too generic though.
We would also want to have non-shadow aware iterator... FlatTreeIterator?
------- Comment #4 From 2011-07-11 02:07:58 PST -------
I found that this change is hard to be done with only naive refactoring
because there is no link from forwarded nodes to content elements.
So I'm trying to introduce that link, which is tracked on Bug 64251 and Bug 64252.
------- Comment #5 From 2012-02-27 19:02:50 PST -------
I marked it DUPLICATE in favor of bug79197.
https://bugs.webkit.org/show_bug.cgi?id=79197

If you have any concerns, please reopen this.

*** This bug has been marked as a duplicate of bug 79197 ***