Mike Taylor: > Having recently discovered UseCounters.conf[1], I'd like to add use > counters for all CSS properties, starting with prefixed props. And > likewise for Moz-prefixed DOM props and methods. > > Ultimately, I'd like us to have a Firefox equivalent to > https://www.chromestatus.com/metrics/css/popularity to help us make > decisions around removing support for non-standard-isms without > breaking the web. > > (https://platform-status.mozilla.org/ seems like a good home for > this kind of data) > > Before I start writing patches, is there any reason to not do this?
Recording use counter information as we parse CSS is not too expensive, although if we were doing it for all ~300 properties I’d be wanting to check that we don’t slow sheet parsing speed down appreciably. It’s probably fine, but see the work that is done when recording one here: https://dxr.mozilla.org/mozilla-central/source/dom/base/nsDocument.cpp#13129 We use a std::bitset<> on the document to store the “use counted or not” for each use counter so the memory overhead is low. Someone with more familiarity about the actual Telemetry payload can say whether it would be alarming to have ~300 new entries, if you plan to eventually include all properties. But starting with recording all of our non-standard property usage sounds fine. Note that UseCounters.conf only supports longhand properties currently, since we record them in here, where we’ve already expanded shorthands out to their component longhands: https://dxr.mozilla.org/mozilla-central/source/layout/style/nsCSSDataBlock.cpp#712 We could handle shorthands by recording them earlier, up in nsCSSParser somewhere. -- Cameron McCormack ≝ http://mcc.id.au/ _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
