[Interest] Best practices for making a Qt facade for a C library

[Damian Ivanov]

Hi Dmitriy,

Wanted to ask if your stuff is open source and is available on github?

2015-01-14 0:26 GMT+01:00 Ian Monroe <ian at monroe.nu>:
> On Tue, Jan 13, 2015 at 10:57 AM, Dmitriy Purgin <dpurgin at gmail.com> wrote:
>>
>> Hello all,
>>
>> I'm developing a small Qt project for SailfishOS (a Linux distribution,
>> Meego descendant, Qt 5 based) and had to use some of PulseAudio (a sound
>> server for POSIX OSes) API functions which are pure C. I've wrapped them in
>> a couple of classes but it's evolving to something bigger now and I'm trying
>> to detach these into a shared library which seems to become a basic
>> PulseAudio binding. It's my first facading of a C library and I'm kind of
>> stuck on the architecture now and hope that someone can share ideas on that.
>
>
> Have you looked at the code generation done by QtGstreamer for glib stuff?
> Not sure if it's any good, just want to make sure you know of it:
> http://cgit.freedesktop.org/gstreamer/qt-gstreamer/tree/
>
>>
>> So with the problem stated, my question is: does anyone know any "good
>> practices" in designing this kind of relationships between classes or can
>> share similar designs to look at? There's no technical problem for me to
>> expose the inner parts of some classes to some other classes, I just
>> wondered if there's a subtle way of doing this.
>
>
> I wrap a C library and had a similar situation. My solution in this case
> would be to give QtPulseAudioSource a new base class named something like
> PulseAudioInterface. That class defines pa_context, it could possibly just
> be a void pointer. It has a member variable for it and a
> setPulseAudioContext method. Then QtPulseAudioContext would have a class
> called something likeblessPulseAudioInterface. QtPulseAudioSource could call
> it in its constructor.
>
> In this way it is pretty hidden from users of the library, and
> QtPulseAudioContext has zero deps on AudioSource.
>
> Ian
>
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