Bug 26194 – DeprecatedPtrList should be removed

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: DOM

[Eric Seidel (no email)]

DeprecatedPtrList should be removed

The last client is on RenderBlock:
    DeprecatedPtrList<FloatingObject>* m_floatingObjects;

And the only times its used, it would work as well or better as a Vector.  See the attached list of uses in the code.  Note that we never insert or remove from the middle of the list.  A vector will be more space efficient!

I'll post a patch to do this tomorrow if no one beats me to it.

[Eric Seidel (no email)]

Created attachment 30953 [details]
list of places that DeprecatedPtrList is used

[Eric Seidel (no email)]

Ok, I lied.  There is one removeRef call in:
void RenderBlock::removeFloatingObject(RenderBox* o)

which does remove from the middle of the list.

That's called from:
void RenderBlock::markAllDescendantsWithFloatsForLayout(RenderBox* floatToRemove, bool inLayout)

which I would expect is expected to be O(N), not O(N^2) as it could be if we moved to a Vector here.  Hum...

[Eric Seidel (no email)]

The only time floatToRemove is ever non-null is from:
void RenderBox::removeFloatingOrPositionedChildFromBlockLists()

Which is only called when an object is losing float status in a styleWillChange or the like.

I was also wrong above.  This will not turn this from O(N) to O(N^2) because we're only going to remove it once.  This will cause pages which make things floating-and-then-not-again slower, but I doubt anyone would notice.  I do expect the iPhone will notice the memory savings on all pages which include floats! :)  So I still think this change is a good one.

[Sam Weinig]

*** This bug has been marked as a duplicate of bug 17425 ***