Re: [Qemu-devel] [PATCH 3/3] configure: add '--disable-cocoa' switch

[Andrzej Zaborowski]

On 17 January 2012 12:06, Andreas Färber <address@hidden> wrote:
> Am 17.01.2012 00:46, schrieb Andrzej Zaborowski:
>> On 14 January 2012 01:42, Andreas Färber <address@hidden> wrote:
>>> Am 08.12.2011 01:41, schrieb Andreas Färber:
>>>> Am 10.11.2011 19:40, schrieb Pavel Borzenkov:
>>>>> When SDL support is disabled, there is no way to build QEMU without
>>>>> Cocoa support on MacOS X. This patch adds '--disable-cocoa' switch and
>>>>> allows to build QEMU without both SDL and Cocoa frontends.
>>>>>
>>>>> Signed-off-by: Pavel Borzenkov <address@hidden>
>>>>> ---
>>>>>  configure |    7 ++++++-
>>>>>  1 files changed, 6 insertions(+), 1 deletions(-)
>>>>>
>>>>> diff --git a/configure b/configure
>>>>> index 401d9a6..4720bb2 100755
>>>>> --- a/configure
>>>>> +++ b/configure
>>>>> @@ -670,6 +670,8 @@ for opt do
>>>>>    ;;
>>>>>    --enable-profiler) profiler="yes"
>>>>>    ;;
>>>>> +  --disable-cocoa) cocoa="no"
>>>>> +  ;;
>>>>>    --enable-cocoa)
>>>>>        cocoa="yes" ;
>>>>>        sdl="no" ;
>>>>
>>>> Tested-by: Andreas Färber <address@hidden>
>>>>
>>>>> @@ -980,7 +982,10 @@ echo "  --disable-sdl            disable SDL"
>>>>>  echo "  --enable-sdl             enable SDL"
>>>>>  echo "  --disable-vnc            disable VNC"
>>>>>  echo "  --enable-vnc             enable VNC"
>>>>> -echo "  --enable-cocoa           enable COCOA (Mac OS X only)"
>>>>> +if test "$darwin" = "yes" ; then
>>>>> +    echo "  --disable-cocoa          disable COCOA"
>>>>> +    echo "  --enable-cocoa           enable COCOA (default)"
>>>>> +fi
>>>>>  echo "  --audio-drv-list=LIST    set audio drivers list:"
>>>>>  echo "                           Available drivers: 
>>>>> $audio_possible_drivers"
>>>>>  echo "  --audio-card-list=LIST   set list of emulated audio cards 
>>>>> [$audio_card_list]"
>>>>
>>>> I see no prior art of any conditional help output in configure. Anthony?
>>>> Andrzej?
>>>
>>> Ping? Should we keep command line options a flat list with comments on
>>> applicability or start introducing tests like above?
>>>
>>> Me, I'd prefer not doing this since the switch cases above don't check.
>>
>> Perhaps --diable-cocoa should be allowed on any platform.  You're
>> right we don't have such checks now, but then it's hard to see
>> downsides of doing them, so I'm quite ambivalent.
>>
>> I still don't see the purpose of the following test in configure though:
>>       if test "$cocoa" = "no" ; then
>>         sdl=yes
>>       fi
>
> The reason is that SDL and Cocoa must not both be detected due to the
> way it is handled in vl.c. Given that Cocoa is enabled by default, SDL
> must not be detected in that case. If Cocoa is disabled, then detecting
> SDL is fine of course.
>
> The alternative would be to check for SDL and, if present, disable
> Cocoa. Still collides with Pavel's patch though - we need to sort out
> how to merge them.
>
>> With it in place and no --disable-cocoa there's no way to compile SDL.
>
>>  --enable-cocoa is also broken as fas as I can tell.
>
> I've been using it for historic reasons without noticeable problems.

The problem I see is that the handler touches the sdl variable, which
is also touched by --enable/disable-sdl.  So the order of the options
on the command line starts to matter.  I think the options should be
treated orthogonally, and then after parsing the command line the
script should bail out if two incompatible options are enabled.

Cheers