332321 - Eliminate nsRuleNode::Get##struct##Data

Status: RESOLVED WONTFIX

(Core :: CSS Parsing and Computation, defect)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

The nsRuleNode::GetStructData can be removed -- I've been wanting to remove them for ages.  This gets rid of an if-else chain that's a performance issue and also is a step towards making the computation table-driven, which we'll need to do for css3-values features that I'd like to implement.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

So it turns out I can't actually do this without doing the whole table-driven thing.

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: work so far

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Actually, if the constructors of the nsRuleData* were all equivalent to memset-to-zero (probably true) and the destructors were all no-op (probably not, due to refcounting, but perhaps doable), then this wouldn't need bug 332335.  And only part of bug 332335 is really need for the css3-values stuff I want to do.

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

See bug 360870 for some changes in this area that we may want to partly revert when doing this.

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

We could probably do this without table-driven stuff, but we'd want to change the ownership model of the data inside nsCSSStruct (to user manages).

Also, the nsRuleNode::GetStyleData code would need to look like:

  nsStyleSet *set = mPresContext->PresShell()->StyleSet();

  nsRuleData *ruleData = set->PushWalkingRuleData();

  ... WalkRuleTree(...)

  set->PopWalkingRuleData();

since we can recur into this code.

Comment 6

[Xidorn Quan [:xidorn] UTC+11]

nsRuleNode is gone.