On Thu, Feb 16, 2017, at 10:25 PM, Gijs Kruitbosch wrote: > On 16/02/2017 06:51, Xidorn Quan wrote: > > Tracking bug: https://bugzilla.mozilla.org/show_bug.cgi?id=903372 > > > > Summary: > > * It has been removed from the spec years ago. > > * No other browser supports it. > > * We pay performance penalty for it. > > * It makes things trickier for stylo to handle URL values. > > > > The tricky thing is that nsParserUtils::ParseFragment currently relies > > on xml:base. That is going to be fixed in > > https://bugzilla.mozilla.org/show_bug.cgi?id=1313278 > > > > Are there any objections? > > No objection, just a caveat that this looks like it will affect Reader > Mode, and there isn't great test coverage for this because Reader Mode > itself already does URL rewriting in addition to what parsefragment > does. bug 1280888 is relevant reading.
Thanks for the pointer. > Furthermore, a question about how this relates to the HTML <base> > element - is that going to continue to be supported and/or does it imply > similar perf penalties / trickiness? This doesn't affect the <base> element. It would continue to be supported. It doesn't have similar pref penalty given that it is a document-wide URL. The perf penalty of xml:base is basically that we have to dynamically construct a URL from bottom to top along the tree whenever we need a base URL of an element. And since this URL may be constructed dynamically, the caller would have to hold a strong reference to it, and thus an additional refcount manipulation. So a URL not dynamically generated would be enough to avoid that penalty. - Xidorn _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
