January 2019 - 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*be sure to audit all code that assigns a non-boolean value to m_2* because implicit type coercion into boolean is no longer in effect.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.

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Support "registerProtocolHandler" in WebKit2
by Gyuyoung Kim 20 Apr '20

20 Apr '20

Hello, I would like to listen what do you think to support 'registerProtocolHandler' in WebKit2. This feature is to execute web content through registered custom protocol. - For example, web content can register "mailto" custom protocol using this feature, <script> navigator.registerProtocolHandler("mailto", "https://mail.naver.com/", "Web Mail"); </script> <html> <head> <title>Web Protocol Handler Sample - Test</title> </head> <body> <p>Send an email : <a href="mailto://">this !</a></p> </body> </html> Besides this feature has been supported by Mozilla and Chromium (From Mozilla 3.0, Chromium 13). - https://developer.mozilla.org/en-US/docs/Web/API/Navigator/registerProtocol… - https://developer.mozilla.org/en/docs/Web-based_protocol_handlers The feature is included in the W3C recommendation 28 released on Oct. 2014. - W3C spec : http://www.w3.org/TR/html5/webappapis.html#custom-handlers IIRC, some WebKit1 ports supported this feature though, those ports were deprecated. Now WebKit port supports this feature no more. There is a very old bug to support this feature though, it wasn't maintained so far. Recently I updated it based on latest WebKit. - https://bugs.webkit.org/show_bug.cgi?id=92749 Feel free to give me any feedback about this feature. Gyuyoung.

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[CSSOM View] Smooth scroll behavior via CSS property / DOM scroll* API
by Frédéric Wang 13 Feb '20

13 Feb '20

Hi all, This email is to announce that I have started to work on (programmatic) smooth scrolling in WebKit from the CSSOM View specification [1]. To use this effect, web developers can pass a behavior parameter (auto, smooth, or instant) to Element.scroll, Element.scrollTo, Element.scrollBy, Element.scrollIntoView, Window.scroll, Window.scrollTo or Window.scrollBy [2]. When behavior is auto, the instant/smooth characteristic is actually taken from the value of a new CSS scroll-behavior property [3]. This new feature will be protected by a compile flag (enabled by default) and a runtime flag (an experimental feature). If you are interested, you can follow advancement on Bugzilla [4]. Incidentally (and since that was convenient to do it before) I also added some basic support for new ScrollIntoView options [5] [6] that allow to specify how you want the revealed element to be aligned with respect to its scrollable ancestors. Cheers, Frédéric [1] https://drafts.csswg.org/cssom-view [2] https://drafts.csswg.org/cssom-view/#dictdef-scrolloptions [3] https://drafts.csswg.org/cssom-view/#propdef-scroll-behavior [4] https://bugs.webkit.org/show_bug.cgi?id=188043 [5] https://bugs.webkit.org/show_bug.cgi?id=189258 [6] https://drafts.csswg.org/cssom-view/#dictdef-scrollintoviewoptions

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WebKit project in Coverity
by Carlos Alberto Lopez Perez 09 Jan '20

09 Jan '20

Hi, Coverity is an static analysis tool that allows to find bugs and vulnerabilities on the source code via static analysis. For open source projects, they offer free usage of their platform. The WebKit project is already registered there since a while. [1] To read the reports in detail or run new scans you have to be member of the WebKit project in Coverity. I happen to be one of the admins there, and I will happily grant you access to this platform if you are a WebKit committer (listed in contributors.json). So if you are interested in this, just send me an email requesting access. Regards ------- [1] https://scan.coverity.com/projects/webkit

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C++17 is here. Should we use it?
by JF Bastien 26 Jun '19

26 Jun '19

Hello WebKilters, Our Chrome-y friends are considering the use of C++14 <https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source…>. I have to say that C++14 in WebKit has been quite amazing, and we should consider using C++17: it has many wonderful new things <https://github.com/tvaneerd/cpp17_in_TTs/blob/master/ALL_IN_ONE.md>, some of which we already use through WTF’s re-implementation of library features. By now (table as witness <http://en.cppreference.com/w/cpp/compiler_support>) most C++17 languages features are in clang and GCC, and MSVC isn’t doing too bad either. Language things can just come through WTF if we really want them. So how about it? JF

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Re: [webkit-dev] [webkit-help] ResizeObserver
by Antonio Gomes 01 Apr '19

01 Apr '19

moved to webkit-dev, bcc'ing webkit-help +Cathie I know Cathie is working on it. Cathie, feel free to provide a status update. On Tue, Jan 22, 2019 at 4:06 PM Eric Gorr <ericgorr(a)gmail.com> wrote: > > Will do. > > Might be worth mentioning this feature on https://webkit.org/status ... ? > > On Tue, Jan 22, 2019 at 2:57 PM Simon Fraser <simon.fraser(a)apple.com> wrote: >> >> On Jan 22, 2019, at 11:46 AM, Eric Gorr <ericgorr(a)gmail.com> wrote: >> >> I was just wondering when we might expect the ResizeObserver ( https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver ) to be supported in webkit ? >> >> >> Please express your interest on https://bugs.webkit.org/show_bug.cgi?id=157743 >> >> I don't' have anything to share about a schedule for this feature. As always, we're taking patches! >> >> Simon >> > _______________________________________________ > webkit-help mailing list > webkit-help(a)lists.webkit.org > https://lists.webkit.org/mailman/listinfo/webkit-help

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Rename AtomicString to AtomString
by Darin Adler 04 Mar '19

04 Mar '19

So, did we reach consensus that we should rename AtomicString to AtomString? — Darin

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For your consideration: Naming scheme for fooIfExists/ensureFoo
by Darin Adler 22 Feb '19

22 Feb '19

Lets bike shed! For some time, functions with names like fooIfExists and ensureFoo have been bothering me. I find both names kind of opaque and unpleasant. Here’s an example: StyleResolver* styleResolverIfExists(); StyleResolver* ensureStyleResolver() What do you think of these names instead? StyleResolver* optionalStyleResolver(); StyleResolver& requiredStyleResolver(); I like them better. Note also that I think the requiredStyleResolver function should return a reference so nobody is tempted to do null checks. It seems like the C++ community likes the name optional for this concept; isn’t there some kind of std::optional template? -- Darin

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Reducing globals
by Alex Christensen 31 Jan '19

31 Jan '19

I am embarking on a journey to reduce the number of global variables and singletons we use instead member variables on the proper objects. Feel free to join! Specifically, I’m looking into reducing the number of members in the NetworkProcessCreationParameters structure. Many of them need to go to NetworkSessionCreationParameters instead. Could those maintaining the libsoup and libcurl networking implementations please lend a hand and move the members enclosed in USE(SOUP) or USE(CURL)? I have done similar moves in https://trac.webkit.org/changeset/238654/webkit and https://trac.webkit.org/changeset/238630/webkit if you would like a pattern to follow.

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libsoup and libcurl networking implementations
by Alex Christensen 20 Jan '19

20 Jan '19

TL; DR could someone get my patch from https://bugs.webkit.org/show_bug.cgi?id=193580 working on Linux and Windows? As part of the quest to reduce process-global state especially in the NetworkProcess, I’m moving NetworkStorageSession ownership from a static map to a member variable of the NetworkProcess object. To accomplish this I eliminated all calls to NetworkStorageSession::storageSession and NetworkStorageSession::defaultStorageSession in WebCore, replacing them by a client call to get a NetworkStorageSession from the WebKit/WebKitLegacy layer in https://trac.webkit.org/r240117 but I did not remove all such calls from the libsoup and libcurl networking implementations. The call to NetworkStorageSession::defaultStorageSession CurlResourceHandleDelegate.cpp and ResourceHandleCurl.cpp shouldn't be too hard to remove by asking the NetworkingContext for the storage instead of calling the static functions, but the calls in DNSResolveQueueSoup.cpp are a little bit trickier. On Cocoa platforms, DNS lookup relies on state that is more global than a NetworkSession. On Linux right now, it seems to use state on the default NetworkStorageSession, which is effectively global right now. I think the best solution that maintains the status quo right now would be to keep the default NetworkStorageSession global in WebKit2 right now, but that requires a little bit more work than I can do blindly and iteratively with EWS. I’d appreciate someone with a Linux development machine getting it working.

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