[OpenJDK 2D-Dev] RFR(XS): 8213944: Fix AIX build after the removal of Xrandr.h and add a configure check for it

[Magnus Ihse Bursie]

On 2018-11-19 18:56, Volker Simonis wrote:
> Hi Phil,
>
> I'd like to kindly ask you to suggest how we can proceed with this issue.
>
> As I wrote before, Xrandr is not officially supported on AIX and there
> are no official packages available for it. There are some OpenSource
> sites for AIX which provide Xrandr, but they are all not compatible
> with the default native libraries (e.g. the open source Xrandr package
> depends on another open source package of Xrender.so.1 but the system
> only provides Xrender.so.0 natively). We can't compile the whole JDK
> (i.e. libawt_xawt.so) against some open source package of Xrender.so.1
> because that simply won't be available on the majority of systems.
>
> Remember that forcing people to install these open-source packages
> even as a build dependency is like expecting Linux users to install
> some non-official packages just to be able to build. Especially in
> corporate environments that's not easy. Moreover the benefit would be
> really minimal, because the Xrandr functionality won't be available at
> runtime anyway.
>
> So to cut a long story short, I see two options:
>
> 1. Go with my current patch (ugly but efficient)
>
> 2. Check-in in an AIX specific version of XRander.h/randr.h under
> src/java.desktop/aix (OK for me, but that would actually negate the
> initial purpose of "8210863: Remove Xrandr include files")
>
> Do you have a better proposal?
I think the change look good, and I vote for strategy 1. As Thomas 
suggested, if the AIX ifdefs look bad we can create a new define, but 
I'm not sure that's really helpful - after all, it's just on AIX we 
currently have no r&r. Having a define would mostly be needed if it was 
multiple OSes, or similar more complex situations, that would have/not 
have the r&r extension.

Yet another solution, to get rid of the ifdefs, is to move the relevant 
Xranrd dependent functions into a new, separate file, like 
awt_GraphicsEnv_randr.c, and then in the build exclude it on AIX (or, 
perhaps if it's worth the trouble, on all platforms where configure did 
not find Xrandr).

/Magnus

>
> Thank you and best regards,
> Volker
>
> On Fri, Nov 16, 2018 at 11:22 AM Volker Simonis
> <volker.simonis at gmail.com> wrote:
>> On Thu, Nov 15, 2018 at 6:01 PM Philip Race <philip.race at oracle.com> wrote:
>>> PS I am not sure why xrandr headers would not be available for AIX.
>>> They are a standard part of the xdistribution.
>>>
>> I'm not an X11 guru, but as far as I understand, xrandr is an
>> extension and as such it doesn't have to be supported by every
>> implementation. To the best of my knowledge (I've just started another
>> poll among some experts) AIX doesn't support Xrandr and does not have
>> the corresponding headers.
>>
>>> If true, think what you are going to have to do is add a
>>> --with-xrandr-include option
>>> and provide it that way.
>>>
>> What if there are no standard Xrandr headers on a platform? Do you
>> really want to force users to get them from some dubious sources just
>> for building the OpenJDK? Sorry, but I don't think that's a good
>> solution. Than I'd rather prefer the ugly ifdefs (or I check the
>> headers back in again in an AIX-specific directory :)
>>
>> Thank you and best regards,
>> Volker
>>
>>> -phil.
>>>
>>> On 11/15/18, 8:55 AM, Philip Race wrote:
>>>> Hmm. I don't like the ifdefs.
>>>>
>>>> Xrandr is a requirement for the build. If its not there at runtime
>>>> that's OK.
>>>>
>>>> -phil.
>>>>
>>>> On 11/15/18, 8:06 AM, Volker Simonis wrote:
>>>>> Hi,
>>>>>
>>>>> can I please have a review for the following small change:
>>>>>
>>>>> http://cr.openjdk.java.net/~simonis/webrevs/2018/8213944/
>>>>> https://bugs.openjdk.java.net/browse/JDK-8213944
>>>>>
>>>>> Change JDK-8210863 removed the Xrandr.h/randr.h headers from the
>>>>> OpenJDK sources but forgot to add a configure check for the Xrandr
>>>>> extension which is now a build dependency.
>>>>>
>>>>> The change also broke the AIX build. AIX never supported Xrandr, but
>>>>> that was only detected at runtime, when the JDK was unable to
>>>>> dynamically load libXrand.so. Now, without Xrandr.h/randr.h in the
>>>>> source tree any more, we have to conditionally compile some parts of
>>>>> src/java.desktop/unix/native/libawt_xawt/awt/awt_GraphicsEnv.c such
>>>>> that it doesn't require the definitions and declarations from
>>>>> Xrandr.h/randr.h any more.
>>>>>
>>>>> Thank you and best regards,
>>>>> Volker