August 2020 - webkit-dev - lists.webkit.org

PSA: Bit fields won't be packed on Windows if you mix types
by Ryosuke Niwa 04 Sep '20

04 Sep '20

Hi, Unlike gcc and clang, MSVC pads each consecutive member variables of the same type in bitfields. e.g. if you have: struct AB { unsigned m_1 : 31; bool m_2 : 1; } then *MSVC pads m_1 and allocates sizeof(unsigned) * 2 for AB* whereas gcc and clang only allocate sizeof(unsigned) * 1 for AB. This is *not a compiler bug*. It's a spec. compliant behavior, and may in fact have a better run-time performance in some situations. However, for core objects like RenderObject and InlineBox, allocating extra 4-8 bytes per each object is prohibitory expensive. In such cases, please *use the same POD type for all bitfield member variables*. (Storage class classifiers and variable qualifiers seem to have no effect on how variables are packed; e.g. mutable, const, etc...). For example, MSVC will allocate sizeof(unsigned) * 1 for AB if we rewrite the above code as: struct AB { unsigned m_1 : 31; unsigned m_2 : 1; } When you're making this change, *be sure to audit all code that assigns a non-boolean value to m_2* because implicit type coercion into boolean is no longer in effect. For example, AB ab; ab.m_2 = 2; puts(ab.m_2 ? "true" : "false"); will print "true" before the change and will print "false" after the change. An easy way to ensure you've audited all such code is to add getters and setters for all bitfield member variables or wrap them in a special structure or class as done in http://trac.webkit.org/changeset/103353 and http://trac.webkit.org/changeset/104254. Best regards, Ryosuke Niwa Software Engineer Google Inc.

4 8

Request for position on hasDroppedEntry in PerformanceObserverCallback
by Nicolás Peña 01 Sep '20

01 Sep '20

Hi, We'd like to request an official position on a very small addition to PerformanceTimeline specification. We've added a hasDroppedEntry parameter to PerformanceObserverCallback, which is in https://w3c.github.io/performance-timeline/#the-performanceobserver-interfa…, and logic for it in https://w3c.github.io/performance-timeline/#queue-the-performanceobserver-t…. It lets a developer know when an entry has been dropped from a buffer that the PerformanceObserver cares about. We reached this solution when discussing https://github.com/w3c/performance-timeline/issues/169 in a WebPerf WG call.

2 1

Request for position on Storage Buckets API
by Ayu Ishii 31 Aug '20

31 Aug '20

Hi WebKit-dev, We would like to ask for WebKit's early position on Storage Buckets API. Storage Buckets API grants sites the ability to create multiple storage buckets[1], where the user agent may choose to delete each bucket independently of other buckets. By contrast, today's user agents have a binary choice of either persisting or deleting all the data stored by a site. Chrome is preparing to prototype. Early discussions of Storage Buckets API have been held at TPAC 2019 attended by Youenn from the WebKit team. Notes from this discussion have been linked below. Relevant links: * Explainer: https://github.com/WICG/storage-buckets/blob/gh-pages/explainer.md * TPAC 2019 Discussion: https://docs.google.com/document/d/1eBWhY91nUfdT2mys3GaNKX4fKPei79Wk-KlWHYf… * ChromeStatus: https://chromestatus.com/feature/5739224579964928 [1] Storage Buckets: https://storage.spec.whatwg.org/#buckets Thank you for your time! - Ayu I.

1 0

Feedback on Blink's text fragment directive proposal
by David Bokan 31 Aug '20

31 Aug '20

Hello webkit-dev, I'd like to solicit feedback as well as an official position from Webkit on our proposal for the text fragment directive: https://github.com/WICG/ScrollToTextFragment. In summary: this is a feature that allows authors and users to craft URLs to pages and specify a snippet of text on the page as a subresource (visually highlighting it and scrolling it into view). Analogous to element-id based fragment anchors but for text. You can try this out today in Chrome Beta by enabling chrome://flags/#enable-text-fragment-anchor. Here's an example link: https://en.wikipedia.org/wiki/Uniform_Resource_Identifier#:~:text=An%20opti… Relevant Links: <https://github.com/WICG/ScrollToTextFragment/blob/master/README.md> Explainer <https://github.com/WICG/ScrollToTextFragment/blob/master/README.md> Spec <https://wicg.github.io/ScrollToTextFragment/> TAG Review <https://github.com/w3ctag/design-reviews/issues/392> (Currently Suspended) Blink Intent Thread <https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/zlLSxQ9BA8Y/…> Issue on Mozilla standards-positions <https://github.com/mozilla/standards-positions/issues/194> We've been using the GitHub repo for issue tracking but happy to take feedback (official or otherwise) in any form. Thank you! David

4 4

How do I set unicode ranges in fonts used by Webkit?
by marcoricci2012＠yahoo.com 31 Aug '20

31 Aug '20

I took this example - https://wiki.gnome.org/Projects/WebKitGtk/ProgrammingGuide/Tutorial - and ran it on my Linux Mint system. I program using GTK+. To the program at the above link, I added the following lines, and while it shows certain glyph from myfont, not all glyphs are displayed. WebKitSettings *wsettings = webkit_web_view_get_settings(webView); webkit_settings_set_default_font_family(wsettings, "myfont"); webkit_settings_set_monospace_font_family(wsettings, "myfont"); webkit_settings_set_serif_font_family(wsettings, "myfont"); webkit_settings_set_sans_serif_font_family(wsettings, "myfont"); How do I specify enabling a unicode range? I want it to have the ability to display everything from U+0001 to U+FFFF because I have some custom glyphs in many places which are spread across the range. I tried adding a css file with @font-face section in it and I tried loading it with gtk_css_provider_load_from_path and gtk_style_context_add_provider_for_screen, but I get a run time error message which says "unknown @ rule." My css file contains the following and nothing else: @font-face { font-family: 'myfont'; src: url('/home/marco/fontfiles/myfont.ttf') format("truetype"); unicode-range: U+0000-FFFF; } I tried this on Linux Mint 19 and I have libgtk-3-dev version 3.22.30 which it says is already at the newest version. Thanks for any response. ~marco

1 0

Request for position on Atomics.waitAsync
by Marja Hölttä 28 Aug '20

28 Aug '20

Hi Webkit-Dev, I would like to get an official position from Webkit on the Atomics.waitAsync JavaScript feature (TC39 Stage 3). Chrome is looking into shipping it in the near future. - Specification: https://tc39.es/proposal-atomics-wait-async/ - ChromeStatus: https://chromestatus.com/feature/6243382101803008 Regards, Marja Hölttä / V8 -- Google Germany GmbH Erika-Mann-Straße 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg Diese E-Mail ist vertraulich. Falls sie diese fälschlicherweise erhalten haben sollten, leiten Sie diese bitte nicht an jemand anderes weiter, löschen Sie alle Kopien und Anhänge davon und lassen Sie mich bitte wissen, dass die E-Mail an die falsche Person gesendet wurde. This e-mail is confidential. If you received this communication by mistake, please don't forward it to anyone else, please erase all copies and attachments, and please let me know that it has gone to the wrong person.

2 1

Request for position on Cookie Store API
by Ayu Ishii 28 Aug '20

28 Aug '20

Hi WebKit-dev, We would like to ask for WebKit's official position on the Cookie Store API. Cookie Store API aims to improve the complexity and performance issues of cookies today by providing an asynchronous alternative to document.cookie and exposing HTTP cookies to service workers. Its interface also encourages developers to make better decisions about security. More information can be found on the explainer below. Chrome has implemented what is currently in the spec, and is planning to ship that soon. - Specification: https://wicg.github.io/cookie-store/ - Explainer: https://github.com/WICG/cookie-store/blob/main/explainer.md - TAG Review: https://github.com/w3ctag/design-reviews/issues/469 - ChromeStatus: https://chromestatus.com/feature/5658847691669504 Thank you.

2 1

Request for Position on Native File System API
by Marijn Kruisselbrink 26 Aug '20

26 Aug '20

Hi Webkit-Dev, We would like to get an official position from webkit for the Native File System API (spec <https://wicg.github.io/native-file-system/>, explainer <https://github.com/WICG/native-file-system/blob/master/EXPLAINER.md>), a API that enables developers to build powerful web apps that interact with files on the user’s local device. It builds on File API for file reading capabilities, and adds new API surface to enable modifying files, as well as working with directories. Chrome has implemented what is currently in the spec, and is planning to ship that soon. Thank you.

2 1

Re: [webkit-dev] Status of custom paint?
by Chris Harrelson 25 Aug '20

25 Aug '20

(re-sending as chrishtr(a)chromium.org, which is actually on the webkit list) On Tue, Aug 25, 2020 at 1:36 PM Chris Harrelson <chrishtr(a)google.com> wrote: > Hi WebKit friends, > > I'm wondering about the status of the implementation of the CSS Painting > API <https://webkit.org/status/#specification-css-painting-api-level-1> > (a.k.a. Custom Paint). I think this > <https://bugs.webkit.org/show_bug.cgi?id=190217> is the tracking bug? > > My understanding is that it's mostly implemented, and the current > implementation is available in Tech Preview. Is it still being worked on? > > Thanks, > Chris >

2 1

EWS now sends email notifications for failures
by Aakash Jain 25 Aug '20

25 Aug '20

Hi Everyone, I am happy to announce another EWS feature: email notifications. From now on, whenever EWS detects any build or test failure caused by a patch, it will send email notification to the patch author. In case of build failure, email will contain the relevant error lines, so as to help in quickly identifying the issue. In case of test failure, email will contain the list of failing test, along with the link to test history. In case someone prefers not to receive these emails, they can unsubscribe either by emailing me or adding their email id to EMAIL_IDS_TO_UNSUBSCRIBE in Tools/BuildSlaveSupport/ews-build/emails.json These email notifications are added as per the feedback received in a survey we did earlier (in https://lists.webkit.org/pipermail/webkit-dev/2019-December/030980.html) Some more details in: https://bugs.webkit.org/show_bug.cgi?id=215220#c0 Please let me know if you notice any issue or have any feedback. Thanks Aakash

1 0