[webkit-reviews] review granted: [Bug 99254] Make ScrollingTree an actual tree of nodes, and have it reflect the ScrollingStateTree : [Attachment 168564] Patch

[bugzilla-daemon at webkit.org]

Simon Fraser (smfr) <simon.fraser at apple.com> has granted Beth Dakin
<bdakin at apple.com>'s request for review:
Bug 99254: Make ScrollingTree an actual tree of nodes, and have it reflect the
ScrollingStateTree
https://bugs.webkit.org/show_bug.cgi?id=99254

Attachment 168564: Patch
https://bugs.webkit.org/attachment.cgi?id=168564&action=review

------- Additional Comments from Simon Fraser (smfr) <simon.fraser at apple.com>
View in context: https://bugs.webkit.org/attachment.cgi?id=168564&action=review


I'm starting to get nervous that none of this is covered by LayoutTests, and
we've already had a couple of crashes in this code. I strongly suggest figuring
out how to test this.

> Source/WebCore/page/scrolling/ScrollingTree.cpp:147
> +void ScrollingTree::updateNodesFromStateNode(ScrollingStateNode* stateNode)

I'd call this updateTreeFromStateNode to make it clearer that it consults
stateNode and its children.

> Source/WebCore/page/scrolling/ScrollingTree.cpp:151
> +    HashMap<ScrollingNodeID, ScrollingTreeNode*>::const_iterator it =
m_nodeMap.find(stateNode->scrollingNodeID());

You should make a typedef for HashMap<ScrollingNodeID, ScrollingTreeNode*>

> Source/WebCore/page/scrolling/ScrollingTree.cpp:175
> +	       HashMap<ScrollingNodeID, ScrollingTreeNode*>::const_iterator it
= m_nodeMap.find(stateNode->parent()->scrollingNodeID());
> +	       if (it != m_nodeMap.end()) {
> +		   ScrollingTreeNode* parent = it->value;
> +		   newNode->setParent(parent);
> +		   parent->appendChild(newNode.release());
> +	       }

If we don't find the parent, what then? Is that an error? Should it assert?