Bug 210415 – [LFC][TFC] Pre-fill columnIntrinsicWidths vector

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[zalan]

it's less error prone than the current append logic.

[zalan]

Created attachment 396252 [details]
Patch

[Sam Weinig]

Comment on attachment 396252 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=396252&action=review

> Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:281
>      Vector<FormattingContext::IntrinsicWidthConstraints> columnIntrinsicWidths;
> +    columnIntrinsicWidths.fill({ }, columnList.size());

I think this can be slightly more efficient if you use the Vector constructor that takes a size + value to fill:

Vector<FormattingContext::IntrinsicWidthConstraints> columnIntrinsicWidths(columnList.size(), { });

 (or, if std::is_pod<FormattingContext::IntrinsicWidthConstraints>::value is true, you can just pass the size).

> Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:341
>          Vector<ColumnMinimumWidth> columnMinimumWidths;
> +        columnMinimumWidths.fill({ }, columns.size());

Same here.

[Sam Weinig]

(In reply to Sam Weinig from comment #2)
> Comment on attachment 396252 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=396252&action=review
> 
> > Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:281
> >      Vector<FormattingContext::IntrinsicWidthConstraints> columnIntrinsicWidths;
> > +    columnIntrinsicWidths.fill({ }, columnList.size());
> 
> I think this can be slightly more efficient if you use the Vector
> constructor that takes a size + value to fill:
> 
> Vector<FormattingContext::IntrinsicWidthConstraints>
> columnIntrinsicWidths(columnList.size(), { });
> 
>  (or, if std::is_pod<FormattingContext::IntrinsicWidthConstraints>::value is
> true, you can just pass the size).
> 
> > Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:341
> >          Vector<ColumnMinimumWidth> columnMinimumWidths;
> > +        columnMinimumWidths.fill({ }, columns.size());
> 
> Same here.

(yes, it now annoys me that the Vector::fill() and the filling Vector constructor take their arguments in opposite order).

[zalan]

(In reply to Sam Weinig from comment #2)
> Comment on attachment 396252 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=396252&action=review
> 
> > Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:281
> >      Vector<FormattingContext::IntrinsicWidthConstraints> columnIntrinsicWidths;
> > +    columnIntrinsicWidths.fill({ }, columnList.size());
> 
> I think this can be slightly more efficient if you use the Vector
> constructor that takes a size + value to fill:
> 
> Vector<FormattingContext::IntrinsicWidthConstraints>
> columnIntrinsicWidths(columnList.size(), { });
> 
>  (or, if std::is_pod<FormattingContext::IntrinsicWidthConstraints>::value is
> true, you can just pass the size).
> 
> > Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:341
> >          Vector<ColumnMinimumWidth> columnMinimumWidths;
> > +        columnMinimumWidths.fill({ }, columns.size());
> 
> Same here.
Thanks Sam. Yeah, I should have looked at the c'tors (funny side note; whenever I try to use some WTF APIs, someone tells me there's a more efficient way to do it.:)

[zalan]

Created attachment 396277 [details]
Patch

[EWS]

ChangeLog entry in LayoutTests/ChangeLog contains OOPS!.

[zalan]

Created attachment 396279 [details]
Patch

[EWS]

Committed r260009: <https://trac.webkit.org/changeset/260009>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 396279 [details].

[Radar WebKit Bug Importer]

<rdar://problem/61718322>

[Sam Weinig]

(In reply to zalan from comment #4)
> (In reply to Sam Weinig from comment #2)
> > Comment on attachment 396252 [details]
> > Patch
> > 
> > View in context:
> > https://bugs.webkit.org/attachment.cgi?id=396252&action=review
> > 
> > > Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:281
> > >      Vector<FormattingContext::IntrinsicWidthConstraints> columnIntrinsicWidths;
> > > +    columnIntrinsicWidths.fill({ }, columnList.size());
> > 
> > I think this can be slightly more efficient if you use the Vector
> > constructor that takes a size + value to fill:
> > 
> > Vector<FormattingContext::IntrinsicWidthConstraints>
> > columnIntrinsicWidths(columnList.size(), { });
> > 
> >  (or, if std::is_pod<FormattingContext::IntrinsicWidthConstraints>::value is
> > true, you can just pass the size).
> > 
> > > Source/WebCore/layout/tableformatting/TableFormattingContext.cpp:341
> > >          Vector<ColumnMinimumWidth> columnMinimumWidths;
> > > +        columnMinimumWidths.fill({ }, columns.size());
> > 
> > Same here.
> Thanks Sam. Yeah, I should have looked at the c'tors (funny side note;
> whenever I try to use some WTF APIs, someone tells me there's a more
> efficient way to do it.:)

(Alas, we have been adding little optimizations for years here. Admittedly, most are around avoid extra size checks when we know things are uninitialized and who knows if compilers right now might be able to do that for us, but alas, here we are).