[webkit-dev] Proposal for a new way to handle porting #ifdefs

[George Staikos]

On 5-May-09, at 10:49 AM, Darin Adler wrote:
> On May 4, 2009, at 7:45 PM, George Staikos wrote:
>
>> 1) In some cases some things apply to more than one OS so we have:
>> #if OS(x) || OS(y) || OS(z) ...
>> I think we should use:
>> #if OS(x,y,z)
>
> How? Macros don’t have overloading with the same macro but  
> different numbers of parameters.

    Hm I guess variable argument macros are not supported everywhere  
we need them.  Oh well.

On 5-May-09, at 11:16 AM, Maciej Stachowiak wrote:

>
> On May 4, 2009, at 7:45 PM, George Staikos wrote:
>
>>
>> I really like this and it goes in the direction that I was hoping  
>> for as well.  Hopefully we can get the WINCE port merged upstream  
>> before we make this change. :-)
>>
>> Some comments I have:
>>
>> 1) In some cases some things apply to more than one OS so we have:
>> #if OS(x) || OS(y) || OS(z) ...
>> I think we should use:
>> #if OS(x,y,z)
>
> I think using the "||" operator is more clear, except perhaps in  
> cases where there is a well-defined OS family, such as the Unix- 
> like family of operating systems, or the Windows family. In that  
> case, the OS family should get is own macro.

    Well my idea probably won't work anyway given that not enough  
compilers we need to support can handle it.

>> 1b) WINCE actually includes plenty of WIN but in some cases does  
>> things differently.  How to make this distinction without lots of  
>> && and ||?
>
> Perhaps we need another basic OS macro besides WINCE and WIN, which  
> would refer to only full/desktop versions of Windows. Or maybe WIN  
> should mean desktop Windows, and some new macro could represent the  
> facilities that are common to Windows and Windows CE. Then it's  
> just a matter of using the right ifdefs in the right place.

    So something like this (for example) in Platform.h?

#if OS(WINMOBILE)
#define WTF_OS_WINCE 1
#endif

#if OS(WINCE) || OS(WINDESKTOP)
#define WTF_OS_WIN 1
#endif

Then OS(WIN) would mean any Windows flavour, and OS(WINCE) would mean  
any flavour of Windows CE.


>> Again, fully support these changes and perhaps some more too.   
>> Just give us a bit of time to find the right way to merge the  
>> WINCE stuff in first please!
>
> I wouldn't expect us to start changing things next week, but since  
> generally I've heard support for these changes, I would expect in a  
> month or two at most we'll likely start on deploying them. Most  
> likely we will come up with a system that allows gradual migration.  
> At some point, we'll likely require new code to use new-style  
> macros only and not the old PLATFORM stuff.

    Great!  Well I'm ready to start packaging things up.  Will try to  
get the first (and most relevant) parts ready this week.

--
George Staikos
Torch Mobile Inc.
http://www.torchmobile.com/