[Linuxsampler-devel] Load Instrument patch (was: LSCP event notification notes)

[Rui N. C. <rn...@rn...>]

Hi,

Myself wrote:
>
>   I'm sure, for the time being, we can fool things up on the server and,
> upon receiving a LOAD INSTRUMENT command, the server will do:
>
>   1) Check for file validity, by checking for it's existence and naively
> verify if it's of one of the supported formats (gig, dls or whatever).
>
>   2) If yes, send the "OK" response immediately to the client, and set the
> progress status variable to "0" (zero percent). Otherwise an error status
> value will be set (e.g. "ERR").
>
>   3) Load the instrument file as it would do normally, as is.
>
>   4) Right after the load completes, just update the status variable with
> a succesful "OK", or "ERR" otherwise. Let's face it, the error status may
> hold the actual final response to the LOAD INSTRUMENT command, as it was
> until now.
>
>   The value stored on this server channel status variable is exactly the
> one that will be held on the INSTRUMENT_STATUS field of the GET
> CHANNEL_INFO command. Clear?
>
>   Honestly, I think this isn't that hard to do on the server side. The
> actual progress threading and probable libgig changes can be just left to
> when Christians get back. Until then, everybody will be happier, me and
> qsampler :)
>

Not hard at all ;)

As a proof-of-concept, on attachment to this post, you may find a
diff-patch to the linuxsampler_0_2_0_cvs20040613 tarball on ls.org,
corresponding to the source tree just before the latest CVS revolution.
Maybe it's applicable to current CVS HEAD too, however I didn't tested it
yet myself.

Specifically, this patch makes the LOAD INSTRUMENT command to return
immediately, almost/always with an "OK" response, while spawning the
proper instrument file loading in the background.

The new INSTRUMENT_STATUS item from GET CHANNEL INFO inquiry command is
where one checks for a successfull load. The instrument status value holds
the load progress percentage if positive, currently only "0" and "100" ;)
Otherwise, in case of a load exception error, the instrument status
variable will hold a negative value.

As proposed, the instrument file load is considered successful and
complete when and only when INSTRUMENT_STATUS holds a "100" value.


>   If all this is OK, I can make the changes myself to the draft document.
> Yet again, it will bump to v.09. The summary preview of changes are:
>
>   4.4.1 LOAD INSTRUMENT slight semantics change;
>   4.4.9 GET CHANNEL INFO response new status field, INSTRUMENT_STATUS;
>   6.6 INSTRUMENT_LOADING event type simply vanishes away.
>

Just hoping this patch gets tested and reviewed, and ultimately found
applicable, I'll start making the document changes in no time.

Hope to hear from you.

Cheers.
-- 
rncbc aka Rui Nuno Capela
rn...@rn...