[webkit-dev] Easing printf based debugging in WebKit with an helper.

[Yong Li]

2012/7/19 Brady Eidson <beidson at apple.com>:
>
> On Jul 19, 2012, at 10:53 AM, Andreas Kling <kling at webkit.org> wrote:
>
> On Tue, Jul 10, 2012 at 4:52 PM, Brady Eidson <beidson at apple.com> wrote:
>>
>>
>> On Jul 10, 2012, at 5:25 AM, Alexis Menard <alexis.menard at openbossa.org>
>> wrote:
>>
>> > On Mon, Jul 9, 2012 at 6:53 PM, Brady Eidson <beidson at apple.com> wrote:
>> >>
>> >> On Jul 9, 2012, at 2:43 PM, Alexis Menard <alexis.menard at openbossa.org>
>> >> wrote:
>> >>
>> >>> Hi,
>> >>>
>> >>> For those who "secretly" use printf debugging :). I know the
>> >>> recommended way is to use a debugger and it's not the point of this
>> >>> discussion.
>> >>
>> >> A lot of us do this, and sometimes it's necessary.  I agree with the
>> >> gripe and support adding something easier.
>> >>
>> >>> So I propose wtf() and its stream operator.
>> >>>
>> >>> Usage :
>> >>>
>> >>> wtf()<<"Hello"<<"World"<<3<<4.53322323; will output : Hello World 3
>> >>> 4.53322
>> >>
>> >> There is no reason to bring in stream operators - that are willfully
>> >> absent from WebCore - just for debugging.
>> >>
>> >
>> > But it's really nice for that purpose, and somehow match std::cout
>>
>> And we quite purposefully don't use std::cout in the project.
>>
>> >> Overloading functions works just as well.
>> >
>> > I'm not sure to understand what you mean here…
>>
>> I mean relying on C++'s overloading of functions for the different types
>> you'd like to printf debug.
>>
>> void debug(WebCore::String&);
>> void debug(WebCore::Frame*);
>> void debug(WebCore::Node*);
>>
>> etc etc etc.
>>
>> debug(someFrame);
>> debug(someNode);
>> debug(someString);
>>
>> Especially that last one would help me from remembering how to type
>> "printf("%s", someString.utf8().data())" which is all I've ever really
>> wanted.
>
>
> Hello fellow printfers!
>
> While I'm just as ashamed of my printf habits as the next guy, I think it'd
> be great if we could move forward with this somehow.
>
> Coming from a background in Qt, the stream operator syntax looks perfectly
> normal to me, perhaps you could expand on why we want to avoid using these
> in WebKit. Is there a technical reason, or is it more of a language purity
> issue?
>
>
> A possible technical reason - that I am 100% theorizing about - is that it
> might bring in more libraries at link time or runtime since it would be the
> absolute first use of stream operators in the project.
>
> That possibility aside, the stronger part of my objection is language
> purity.  WebCore uses C++ as "C with classes" and I don't think it's worth
> it to confuse new (or existing) contributors about that going forward.
>

Can you elaborate why WebCore uses C++ as  "C with classes"?

We are using namespace, template, operator overloading, virtual
functions, multi-inheritance, scope object, and even
pointer-to-member. We prefer Vector<> to C array, and prefer
OwnPtr/RefPtr to C pointer. Where is C stuff?

> Regardless, adding a consistent set of debug(WebCore::MyCoolOverload)
> methods as suggested would still be massively useful.
>
>
> Definitely.
>
> ~Brady
>
>
> -Kling
>
>
>
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