kdelibs/khtml/rendering

[Darin Adler]

On May 25, 2004, at 9:05 AM, Michael Matz wrote:

> On Mon, 24 May 2004, Leo Savernik wrote:
>
>> -    RenderCanvas* canvas() const;
>> +    // Cannot use static_cast because RenderCanvas depends on 
>> RenderObject.
>> +    // Thus, the class hierarchy cannot be known at this point.
>> +    RenderCanvas* canvas() const
>> +    { return 
>> reinterpret_cast<RenderCanvas*>(document()->renderer()); }
>
> Uhm, I've no idea about khtml's class hierarchy, but a 
> reinterpret_cast<>
> is probably the wrongest cast to use here.  What's the return type of
> renderer(), and what's it's relation to RenderCanvas?  It's dynamic 
> type
> _must_ be a RenderCanvas* if you ever hope the above to work, and in 
> that
> case at least dynamic_cast<> will work, unlike reinterpret_cast<> which
> for instance does no base adjustment.

I'm pretty sure that what the right thing to do is to change this back 
to static_cast, take this function definition out of the RenderObject 
class definition itself, and put the inline function outside the class 
body in render_canvas.h after the definition of RenderCanvas.

Then there's a requirement that anyone calling canvas() includes 
render_canvas.h, which is probably not onerous if they plan to call any 
functions on the result of canvas().

An alternative would be to make this a normal function rather than an 
inline, and put it in render_object.cpp, depending on whether that has 
any measurable code size or efficiency effects.

Keeping the reinterpret_cast is probably a bad idea.

     -- Darin