Convert the implementation of computeLogicalWidth to work with block-flow

[Dave Hyatt]

Convert the implementation of computeLogicalWidth to work with block-flow.  This bug addresses patching the RenderBox computeLogicalWidth function to be block-flow-aware.  It does not cover positioned elements, marquees, flexible boxes, table, etc... just basic elements.

[Dave Hyatt]

Created attachment 68765 [details]
Patch

[Dave Hyatt]

Created attachment 68766 [details]
Clean up the ChangeLog typos.

[Sam Weinig]

Comment on attachment 68766 [details]
Clean up the ChangeLog typos.

View in context: https://bugs.webkit.org/attachment.cgi?id=68766&action=review

> WebCore/rendering/RenderBox.cpp:1492
> +    // Fieldsets do this.

This comment could be improved.

> WebCore/rendering/RenderBox.cpp:1613
> +    Length marginStartLength = style()->marginStartUsing(containingBlock->style());
> +    Length marginEndLength = style()->marginEndUsing(containingBlock->style());
> +    const RenderStyle* containingBlockStyle = containingBlock->style();
> +
> +    // Case One: The object is being centered in the containing block's available logical width.
> +    if ((marginStartLength.isAuto() && marginEndLength.isAuto() && childWidth < containerWidth)
> +        || (!marginStartLength.isAuto() && !marginEndLength.isAuto() && containingBlock->style()->textAlign() == WEBKIT_CENTER)) {
> +        setMarginStartUsing(containingBlockStyle, max(0, (containerWidth - childWidth) / 2));
> +        setMarginEndUsing(containingBlockStyle, containerWidth - childWidth - marginStartUsing(containingBlockStyle));
> +        return;
> +    } 
> +    
> +    // Case Two: The object is being pushed to the start of the containing block's available logical width.
> +    if (marginEndLength.isAuto() && childWidth < containerWidth) {
> +        setMarginStartUsing(containingBlockStyle, marginStartLength.calcValue(containerWidth));
> +        setMarginEndUsing(containingBlockStyle, containerWidth - childWidth - marginStartUsing(containingBlockStyle));
> +        return;
> +    } 
> +    
> +    // Case Three: The object is being pushed to the end of the containing block's available logical width.
> +    bool pushToEndFromTextAlign = !marginEndLength.isAuto() && ((containingBlockStyle->direction() == RTL && containingBlockStyle->textAlign() == WEBKIT_LEFT)
> +        || (containingBlockStyle->direction() == LTR && containingBlockStyle->textAlign() == WEBKIT_RIGHT));
> +    if ((marginStartLength.isAuto() && childWidth < containerWidth) || pushToEndFromTextAlign) {
> +        setMarginEndUsing(containingBlockStyle, marginEndLength.calcValue(containerWidth));
> +        setMarginStartUsing(containingBlockStyle, containerWidth - childWidth - marginEndUsing(containingBlockStyle));
> +        return;
> +    } 
> +    
> +    // Case Four: No auto margins. Just compute normally.
> +    // This makes auto margins 0 if we failed a logicalWidth() < containerWidth test above (css2.1, 10.3.3).
> +    setMarginStartUsing(containingBlockStyle, marginStartLength.calcMinValue(containerWidth));
> +    setMarginEndUsing(containingBlockStyle, marginEndLength.calcMinValue(containerWidth));

I am not sure how hot these functions are, but we could avoid some branches by adding marginStartAndEndUsing()/setMarginStartAndEndUsing() style functions to get/set both at once. You might also consider having the setMargin functions return the length they set, since you often use it on the next line.

> WebCore/rendering/RenderBox.h:198
> +    // of the containing block..

Typo. Double period.

[Dave Hyatt]

Fixed in r68362.