[pulseaudio-discuss] Expand the simple API?

[Tanu Kaskinen]

On Tue, 2013-03-19 at 09:40 +0100, David Henningsson wrote:
> I spent yesterday afternoon writing a small PulseAudio client using the 
> asynchronous API and found that it was a few things to setup; the 
> mainloop, the context, the stream, callbacks etc.
> 
> Just to recap, there are three strategies for feeding data to PulseAudio:
> 
>   * Blocking:
> 
>     pa_simple_write(data, length);
> 
>     or:
> 
>     while (length > 0) {
>         while (pa_stream_writable_size() == 0)
>            pa_mainloop_wait();
>         pa_stream_write(data, pa_stream_writable_size());
>         data += pa_stream_writable_size();
>         length -= pa_stream_writable_size();
>     }
> 
>   * Polling:
> 
>     every now and then do:
>         pa_stream_write(data, pa_stream_writable_size());
> 
> 
>   * Callback:
> 
>     pa_stream_set_write_callback(my_write_callback);
>     pa_mainloop_run();
> 
>     my_write_callback(size_t length) {
>         pa_stream_write(data, length);
>     }
> 
> 
> Looking at the client code, it seems very simple to add 
> pa_simple_writable_size() to the client API, and thus enable the polling 
> scenario for the simple API too.
> 
> Even the callback scenario - which is the most efficient one, I would 
> assume - seems not too difficult to implement in the simple API, as long 
> as the user is aware that the callback will be called from a separate 
> thread (as the simple API is based on a threaded mainloop).
> 
> Sure, more options makes a simple API less simple, but at least the 
> pa_simple_writable_size API wouldn't hurt to implement IMO. The 
> user-friendliness of providing this outweighs the possible lack of 
> simplicity. Or what do you think?

I'd be OK with adding pa_simple_writable/readable_size(). I believe the
multi-threading aspect of adding the write/read callbacks unavoidably
makes writing applications not-simple, so the simple API probably
shouldn't have those callbacks.

-- 
Tanu