443978 - Support mutation of CSSFontFaceRule DOM objects from JavaScript

Status: NEW

(Core :: DOM: CSS Object Model, defect, P3)

Description

[Zack Weinberg (:zwol)]

The initial implementation of CSSFontFaceRule DOM objects as coded in bug 441469 does not include support for modifying those objects from JavaScript.  Specifically, there are stub methods for three interfaces, that always return NS_ERROR_NOT_IMPLEMENTED:

 nsIDOMCSSFontFaceRule::SetCssText
 nsIDOMCSSStyleDeclaration::SetCssText
 nsIDOMCSSStyleDeclaration::SetProperty

(note that there is a custom implementation of nsIDOMCSSStyleDeclaration for CSSFontFaceRule objects, currently called CSSFontDescriptorBlock and hidden away in nsCSSRules.cpp).

These are not technically difficult to implement but are not necessary for people to proceed with bug 441473, and so I am splitting their implementation from bug 441469.

Comment 1

[Zack Weinberg (:zwol)]

These are actually much harder to implement than I thought, because we don't have a good way to make consumers of style data aware that font-face descriptors have changed.  And we're running out of time for feature work, so I'm taking this off the 1.9.1 radar.

Comment 2

[Zack Weinberg (:zwol)]

I no longer work for Mozilla, I am deassigning myself from bugs I have no intention of working on as a volunteer.

Comment 3

[Daniel Glazman (:glazou) (not active in Mozilla any more)]

Sigh. This is severely blocking BlueGriffon's CSS Pro Editor...

Comment 4

[Emilio Cobos Álvarez (:emilio)]

This makes testability of some @font-face bits much harder, and shouldn't be hard now, I'd think...

See https://github.com/w3c/csswg-drafts/issues/3588.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 443978 - Allow mutation of DOM font-face declarations. r=#style

And fix change handling for RemoveProperty, which was supported but didn't
invalidate anything.