Bug 81996 – Disable CSS_SHADERS in Apple builds

• Component: CSS
• Status: RESOLVED FIXED

[Dean Jackson]

We need to turn off shaders for Apple builds. They'll still be available with --enable-css-shaders in build-webkit (or by hardcoding yourself). We'll turn them back on soon.

[Dean Jackson]

<rdar://problem/11092888>

[Dean Jackson]

In fact, I'll move stuff out of FeatureDefines.xcconfig and put the ENABLE flag in Platform.h. This makes it hard to enable from the command line, but is a nicer long term solution.

[Dean Jackson]

Created attachment 133480 [details]
Patch

[Dean Jackson]

We could have used the runtime flag, but that would still mean the CSS parser accepts the shader input. That has the side effect that people can't author content that degrades nicely.

I'd like to hear from Alex before landing this.

[Alexandru Chiculita]

(In reply to comment #4)
> We could have used the runtime flag, but that would still mean the CSS parser accepts the shader input. That has the side effect that people can't author content that degrades nicely.
> 
> I'd like to hear from Alex before landing this.

There is some code that disables parsing for CSS custom() function at runtime.

Here is an extract from http://svn.webkit.org/repository/webkit/trunk/Source/WebCore/css/CSSParser.cpp in function  PassRefPtr<CSSValueList> CSSParser::parseFilter()

#if ENABLE(CSS_SHADERS)
            if (filterType == WebKitCSSFilterValue::CustomFilterOperation) {
                // Make sure parsing fails if custom filters are disabled.
                if (Document* document = findDocument()) {
                    Settings* settings = document->settings();
                    if (!settings || !settings->isCSSCustomFilterEnabled())
                        return 0;
                }
...

Anyway I think it is a good security measure to disable the compile time flag for now.

[Simon Fraser (smfr)]

Comment on attachment 133480 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=133480&action=review

> Tools/ChangeLog:6
> +        https://bugs.webkit.org/show_bug.cgi?id=81996
> +
> +        Reviewed by NOBODY (OOPS!).

This could use some explanation.

[Dean Jackson]

http://trac.webkit.org/changeset/111893